Biomedical subjects

V Belan

Publications and source records attributed to V Belan.

At least 19 recordsLinked to original sources

PubMed2005

In vitro study of astrocytic tumour metabolism by proton magnetic resonance spectroscopy.

In vivo magnetic resonance spectroscopy (MRS) studies of glial brain tumours reported that higher grade of astrocytoma is associated with increased level of choline-containing compounds (Cho) and decreased levels of N-acetylaspartate (NAA) and creatine and phosphocreatine (Cr). In this work, we studied the metabolism of glioma tumours by in vitro proton magnetic resonance spectroscopy (1H-MRS). 1H-MR spectra were recorded in vitro from perchloric acid extracts of astrocytoma (WHO II) and glioblastoma multiforme (WHO IV) samples. We observed differences between astrocytoma and glioblastoma multiforme in the levels of Cho, alanine, lactate, NAA, and glutamate/glutamine. In astrocytoma samples, we found higher MR signal of NAA and lower signal of Cho and alanine. MR spectra of glioblastoma samples reported significantly higher levels of lactate and glutamate/glutamine. In contrast, levels of Cr were the same in both tumour types. We also determined NAA/Cr and Cho/Cr ratios in the tumour samples. The NAA/Cr ratio was higher in astrocytomas than in glioblastomas multiforme. Conversely, the Cho/Cr ratio was higher in glioblastoma multiforme. The results indicate that MRS is a promising method for distinguishing pathologies in human brain and for pre-surgical grading of brain tumours.

Aspartic Acid↗

PubMed2001

Delayed orchiectomy after chemotherapy in patients with advanced testicular cancer.

INTRODUCTION: The therapeutic procedures in the management of testicular cancer are determined by histological findings in the removed testis and by the extent of the disease at the time of diagnosis. However, all advanced tumors could be treated by primary chemotherapy regardless of the histological findings. The current imaging techniques (ultrasound of the testis, abdominal and chest CT examination) and laboratory tests (determination of serum tumor markers AFP and hCG) provide sufficient evidence for the presence of cancer. When the diagnosis of advanced tumor is evident, it is possible to start the treatment without orchiectomy. The aim of this study was to evaluate the advantages of neo-adjuvant chemotherapy with delayed orchiectomy in the management of advanced testicular cancer. MATERIAL AND METHODS: A total of 36 patients with advanced germ cell testicular cancer underwent primary PVB or BEP chemotherapy without previous orchiectomy. Mean age of patients was 32 years. Detailed medical, surgical and urological examination showed pulmonary metastases and/or extensive abdominal tumorous masses imitating acute abdominal crisis and impaired drainage of the kidney due to ureteral obstruction. Searching for the origin, testicular tumor was detected. Eleven patients had a bulky disease in the retroperitoneum (Stage IIC), two had enlarged retroperitoneal lymph nodes (Stage IIB), two had enlarged mediastinal lymph nodes (Stage III) and other 16 patients had also pulmonary metastases, and 5 pts had pulmonary metastases only. The patients were treated with cisplatin-containing combination chemotherapy. Following completion of chemotherapy, orchiectomy was performed alone or simultaneously with retroperitoneal lymph node dissection (RPLND) and/or lung metastasectomy in cases with persistent residual mass. Following orchiectomy the patients were regularly checked and in cases with viable malignant tumor found in the testis sequential chemotherapy was administered. Similarly when the relapse of the disease was detected, the patients were treated with sequential chemotherapy. RESULTS: Complete disappearance of metastases was observed in 12 patients following chemotherapy alone. The residual mass persisted in 24 patients (in 22 out of them in the retroperitoneum and in two patients also in the lungs) and was removed surgically. The viable tumor in the removed tissue was found in one patient. Delayed orchiectomy was performed simultaneously with surgical removal of residual mass in the retroperitoneum in 24 patients and as a separate procedure in 12 patients who have been considered to be complete responders following chemotherapy alone. Residual viable tumor in testicular specimen was found in three patients, necrotic or fibrotic tissue in 18, and mature teratoma in 15 patients. Overall survival of the patients was 26/36 (72.7%) at mean of 56.9 months (range 7-145 months, median 50 months) since the start of the treatment. CONCLUSIONS: In patients with advanced germ cell testicular cancer preference must be given to the early beginning of intensive chemotherapy without the need of tissue diagnosis of primary tumor that should be obtained by orchiectomy. Benefit of this therapeutic approach is the timely management of acute abdominal and/or pulmonary symptoms of life-threatening distant metastases.

Adult↗

PubMed1998

Creatine kinase reaction rates in rat brain during chronic ischemia.

Creatine kinase reaction rates were measured by magnetisation transfer technique in the brain of healthy adult and aged rats and in the rats with mild or severe chronic cerebral ischemia. These measurements indicated that the rate constant of the creatine kinase reaction is significantly reduced in the case of chronic brain ischemia in aged rats. In contrast, occlusion of both carotid arteries in adult rats produced a slight increase in the reaction rate 4 weeks after occlusion. At the same time, corresponding conventional phosphorus magnetic resonance spectra showed negligible changes in signal intensities.

Aging↗

PubMed1998

Prognostic factors in clinical stage I nonseminomatous germ cell testicular tumors: rationale for different risk-adapted treatment.

OBJECTIVE: Surveillance after orchiectomy alone becomes popular for the management of clinical stage I nonseminomatous germ cell testicular tumours (CS I NSGCTT). Effort to identify patients at high risk of relapse leads to searching prognostic factors of CS I NSGCTT. The aim of this study was to identify those patients in whom a surveillance policy is less likely to be successful. PATIENTS AND RESULTS: Seventy-two CS I NSGCTT patients were stratified to different risk-adapted therapeutic approaches according to histopathologic findings of primary tumor removed by inguinal orchiectomy. Eighteen patients (group A) with vascular invasion and majority of embryonal carcinoma component in the primary tumor were treated with adjuvant BEP chemotherapy. None of them experienced disease progression after a median follow-up period of 36 months after orchiectomy. Five patients (group B) with vascular invasion and the majority of teratomatous elements in the primary tumor have been followed up 56 months after orchiectomy. They were treated with primary retroperitoneal lymph node dissection (RPLND). Two of them (40%) had pathologic stage II after RPLND and underwent subsequent chemotherapy. One of them died due to disease progression 29 months following orchiectomy. Another one lives with no evidence of disease (NED). Three patients in pathologic stage I are alive with NED. Forth-nine patients (group C) without vascular invasion have been followed up for a median duration of 37 months after orchiectomy. They were kept under close surveillance, consisted of regular follow-up with tumor markers, chest x-ray and CT of the retroperitoneum. Disease progression was observed in 7 (14.3%) patients after a median duration of 8 months after orchiectomy. They were treated with BEP chemotherapy and live with disease-free median survival of 22 months after completion of therapy. The overall survival rate of all 72 patients was 98.6%. The median survival for all patients was 37 months (range 7-73). CONCLUSIONS: The authors will continue to use surveillance policy only in patients without vascular invasion in the primary tumor.

Adolescent↗

PubMed1997

[Octreotide in the treatment of thyrotropin-secreting pituitary adenomas].

The authors detected in a 30-year-old patient a very rare type of hyperthyroidism caused by a thyrotropin secreting pituitary adenoma. Scintigraphic examination of the pituitary by means of 111In radiolabelled octreotide revealed an increased accumulation of the radiopharmaceutical preparation in the tumour, which confirmed the high density of somatostatin receptors. After onset of octreotide treatment (Sandostatin, Sandoz, Switzerland) 3 x 100 ug/day by the s.c. route a brisk decline and normalization of thyrotropin already after the first dose was recorded. The thyroxine concentration declined slowly to the upper range of normal values. After 5 months treatment despite the positive response to receptor scintigraphy diminution of the adenoma was not recorded. Again an increase of thyrotropin above the upper limit of the reference range and a marked rise of thyroxinaemia were observed. Six months after radical selective trans-sphenoidal adenomectomy normal pituitary function was confirmed.

Adenoma↗

PubMed1996

[Results of long-term follow-up of surgical treatment of pulmonary metastases of testicular germ cell tumors].

The authors analyse 34 cases of surgeries performed due to residual pulmonary metastases with germinative testicular tumours. Good results in the length of survival are ascribed to thoracotomy, or sternotomy with the resection of metastatic foci, i.e. the only method which reliably ascertains the biological nature of residual pulmonary lesion after chemotherapy. (Tab. 1, Fig. 2, Ref. 17.)

Adolescent↗

PubMed1996

The value of prognostic factors in the management of stage I nonseminomatous germ cell testicular tumors (NSGCTT).

The prospective study, carried out from February 1992 to January 1996, included 49 patients in clinical Stage I nonseminomatous germ cell testicular tumors (NSGCTT). They were aged 16-40 years (mean, 25 years). Patients were stratified to different risk-adapted therapeutic approaches according to histopathologic findings of primary tumor removed by inguinal orchiectomy. Eleven patients of the 1st group with vascular invasion and majority of embryonal carcinoma components in the primary tumor were treated with adjuvant chemotherapy (2 cycles of BEP). None of them had disease progression after the follow-up of 4-43+ months (mean, 20.9 months) after orchiectomy. Five patients of the 2nd group with vascular invasion and majority of teratoma elements in the primary tumor were treated with primary retroperitoneal lymph node dissection (RPLND). They were followed-up 29-45+ months (mean, 33.4 months) after orchiectomy. Two of them (40%) had pathologic Stage II after RPLND and underwent subsequent BEP chemotherapy. One of them died due to disease progression in disseminated stage 29 months after orchiectomy. The second one lives with no evidence of the disease (NED). Thirty three patients in the 3rd group without vascular invasion were kept under surveillance. They were followed-up 3-48+ months (mean, 22.3 months) after orchiectomy. Disease progression was observed in 5 of them (15.1%), 7-10 months (mean, 8.8 months) following orchiectomy. These patients were treated with BEP chemotherapy and live with NED 1-16+ months (mean, 9.2 months) after completion of the therapy. The overall survival rate in clinical Stage 1 patients was 97.9%. The authors recommend the surveillance policy only in clinical Stage I NSGCTT patients without vascular invasion in the primary tumor.

Adolescent↗

PubMed1996

Management of germ cell testicular cancer with pulmonary metastases.

Twenty eight patients with germ cell testicular cancer pulmonary metastases received primary chemotherapy including bleomycin, etoposide, and cisplatin (BEP). Complete response was achieved in 21 (75%) patients, in 11 of them CR was achieved following chemotherapy alone. Postchemotherapy surgery of residual mass was performed in 12 (42.9%) patients with normalized serum tumor markers. Retroperitoneal lymph node dissection was performed in one patient, pulmonary surgery in four, and both postchemotherapy treatments in 7 patients. Overall cure rate was 89.3%, 26 (92.9%) patients are still alive at a mean follow-up of 19.7+ months (range, 3-34+ months) after the treatment start. Two (7.1%) patients died: one of them due to disease progression during chemotherapy, and the second one due to postoperative complication (acute respiratory failure). Relapse of disease was observed in one patient 21 months following CR achievement, and sequential chemotherapy was introduced. Authors recommend surgical remove of all radiologically detected residual deposits, because the available imaging methods are not adequate for determining the histologic composition of residual mass, which is decisive for further therapy and has prognostic value.

Adolescent↗

PubMed1995

MR-guided stereotaxy in functional neurosurgery.

MR imaging enables the localization of the anteroposterior commissural line, but sometimes it is difficult to define the anterior commissure point. The corpus callosum is more easily identified in this case. We performed an MR imaging using the following methodology; a single transverse scan from which a coronal scan is planned with compensation. A sagittal scan is prescribed from the coronal slice, compensating for any misalignment of patient position. Finally the scan series are prescribed from the sagittal scan, following which we calculate MR distortion. This methodology was used for functional stereotaxy, and the results correlated well with the classical method.

Brain↗

PubMed1993

Chemotherapy of testicular cancer: 10-year experience.

A total of 250 patients with germ cell testicular tumors were treated by PVB chemotherapy between 1982 and 1992. Mean age of patients was 28.9 years (range 15-52). Thirty-four patients in clinical Stage II (11 patients IIA, 13 patients IIB, and 10 patients IIC) underwent primary retroperitoneal lymphadenectomy (RPL) with subsequent chemotherapy. They were followed-up for a mean of 106.3 months (range 85-125). CR was achieved in 30 patients (88.2%). Three patients relapsed. Twenty-seven patients (79.4%) are alive with no evidence of disease (NED) after a minimum of 5 years since the start of therapy. One hundred and twenty-two patients underwent primary chemotherapy for clinical Stages IM (15 patients), IIA (31 patients, IIB (48 patients) and IIC (28 patients) with RPL in cases with residual mass in the retroperitoneum. They were followed-up for a mean of 47.7 months (range 6-122). CR was achieved in 115 patients (92.7%) (75 of them received chemotherapy alone, 40 patients achieved CR following combined cytostatic-surgical treatment). Eleven patients relapsed. One hundred and nine patients (89.3%) are alive with NED. Ninety-four patients in Stages III and IV (8 patients III, 86 patients IV) underwent primary chemotherapy with additional surgical removal of residual metastases. They were followed-up for a mean of 50.5 months (range 6-125). CR was achieved in 65 patients (69.1%) (32 of them received chemotherapy alone, 33 patients achieved CR following combined cytostatic-surgical treatment). Eleven patients relapsed. Fifty-seven patients (60.6%) are alive NED. There were 11 patients with advanced germ cell testicular cancer (Stages IIC and IV) who underwent initial PVB chemotherapy without previous orchiectomy. Delayed orchiectomy was done simultaneously with surgical removal of residual mass in the retroperitoneum or in the lungs or at completion of chemotherapy alone. The toxicity of chemotherapy was moderate. There were drug-related deaths in ten patients (4%).

Adolescent↗

PubMed1993

[Generation and processing of digital images in radiodiagnosis].

The paper describes universal principles of diagnostic imaging. The attention is focused particularly on digital image generation in medicine. The methodology of display visualization of measured data is discussed. The problems of spatial relation representation and visual perception of image brightness are mentioned. The methodological issues of digital image processing (DIP) are discussed, particularly the relation of DIP to the other related disciplines, fundamental tasks in DIP and classification of DIP operations from the computational viewpoint. The following examples of applying DIP operations in diagnostic radiology are overviewed: local contrast enhancement in digital image, spatial filtering, quantitative texture analysis, synthesis of the 3D pseudospatial image based on the 2D tomogram set, multimodal processing of medical images. New trends of application of DIP methods in diagnostic radiology are outlined: evaluation of the diagnostic efficiency of DIP operations by means of ROC analysis, construction of knowledge-based systems of DIP in medicine. (Fig. 12, Ref. 26.)

Diagnostic Imaging↗

PubMed1993

[Use of the CA 19-9 tumor marker in the diagnosis of pancreatic carcinoma].

The contribution of the tumor marker CA 19-9 to differential diagnosis between malignant and nonmalignant diseases of the pancreas was assessed in a group of 120 patients. On using border values of CA 19-9 80 U/ml, its sensitivity was found to be 84.4% and its specificity 84.8% for carcinomas of the pancreas. Correlation of CA 19-9 values with results of computer tomography and endogenous retrograde cholangiopancreatography in the patients studied yielded an over 80% accordance. In the light of the obtained results, the authors consider determination of CA 19-9 levels to be a suitable method supplementing the imaging examination methods in suspect carcinoma of the pancreas.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed1992

Primary chemotherapy in the management of low stage (IIA and IIB) non-seminomatous germ cell testicular tumours.

In a prospective study a total of 65 patients in clinical stages IIA and IIB nonseminomatous testicular tumours were treated by primary chemotherapy followed by retroperitoneal lymphadenectomy in cases with residual disease. The patients were given a combination of cisplatin, vinblastine and bleomycin, or also etoposide. Sixty-two patients (95.4%) achieved complete response: 39 (60%) by chemotherapy alone and 23 (35.4%) following surgical removal of residual disease. Three patients died; there were two drug-related deaths during PVB chemotherapy, one patient had progression of disease following chemotherapy and died as a result of disease dissemination. Three patients relapsed from complete response following chemotherapy, two of them died within 19 and 29 months after the onset of therapy. The third patient received second-line chemotherapy and gained complete response again. Of the 65 patients, 60 (92.3%) survive with no evidence of disease. The follow-up period ranged from 6 to 79 months (mean 39.4 months, median 39 months).

Adolescent↗

PubMed1992

Stereotactic technique and pathophysiological mechanisms of neurotransplantation in Huntington's chorea.

In Huntington's chorea, embryonal brain tissue (striatum) was implanted in the caudate nucleus bilaterally, using stereotaxy assisted by CT. A special cannula allowed the placement into the brain of 3 or 4 grafts of embryonal tissue along the determined trajectory by one introduction of the cannula. The pathophysiological mechanism of neurotransplantation in Huntington's chorea is to compensate for the degenerated striatal tissue by embryonal striatum, so it is necessary to supply a quantity of embryonal striatal tissue which enables the whole functional integrity. Therefore, we use material from several embryos.

Brain Tissue Transplantation↗

PubMed1992

Monitoring of patients with non-seminomatous germ cell tumors of the testis by determination of alpha-fetoprotein and beta-human chorionic gonadotropin levels and by computed tomography.

The results of a 7-year monitoring of 230 patients with non-seminomatous testicular tumors are reported with respect to the employment of radioimmunoanalysis of alpha-fetoprotein and beta-human chorionic gonadotropin levels and CT examinations of retroperitoneum and lungs. Prior to orchiectomy, elevated levels of at least one of these markers were found in 79% of patients. After orchiectomy, tumor marker levels were in 70.4% of patients in agreement with the results of CT examinations. After the completion of chemotherapy, in more than a half of patients normal tumor marker levels and positive CT findings were observed. These results were most often due to the presence of mature teratoma. In Stage I patients the advantages of tumor marker determinations and CT examinations in the early detection of tumor progression have fully been confirmed.

Biomarkers, Tumor↗

PubMed1992

[Combined therapy in patients with testicular germ cell tumors in the dissemination stage (pulmonary metastasis)].

The efficacy of combined cytostatic-surgical treatment was evaluated in a prospective study involving 70 patients with germinal tumors of the testis metastasizing into the lungs. Complete remission was achieved in 50 (71.4%) patients, 30 of these received only chemotherapy. Thoracotomy was performed in 14 patients with residual pulmonary CT finding, 6 of them underwent bilateral operations. Of the total 21 operations of the lungs residual malignant tumor was found 4 times. After a mean follow up period of 29.8 months since onset of treatment 48 patients (68.6%) survived. Within a mean of 11.4 months after onset of treatment 22 patients (31.4%) died. The authors consider thoracotomy with resection of the metastatic focus to be the only method for determining reliably the biological nature of the residual pulmonary lesion after chemotherapy. The result of the procedure determines the further measures, i.e. sequential chemotherapy or regular check ups. (Tab. 1, Fig. 6, Ref. 15.).

Adolescent↗

PubMed1991

[Radical and selective removal of hyperfunctional hypophyseal adenomas using a transsphenoidal approach].

The authors investigated the possibility of radical removal of adenomas of the pituitary (AH), while preserving remnants of pituitary tissue, in 23 patients with primarily operated hyperfunctional AH producing PRL (14 patients), STH (8 patients) and ACTH (1 patient). Normalization of the pathologically elevated hormone level was achieved by the transsphenoid operation without supplementary treatment in 13 of 16 patients with defined and in 3 of 7 patients with invasively growing AH (PRL in 10, STH in 5 and ACTH in one patient), i.e. in 69.5% Identification and preservation of remnants of the pituitary was possible in 20 patients (in all 16 with defined and in 4 of 7 with invasive AH); 17 of them (73.9%) do not need hormonal substitution. Radical and at the same time selective adenomectomy was achieved in 14 patients (60.9%) incl. three patients with invasively growing tumours. The improved activity of the pituitary is manifested clinically after successful operation in particular in young patients by improved gonadal function.

Adenoma↗

PubMed1991

[Surgical treatment of residual pulmonary metastasis of testicular germ cell tumors after chemotherapy].

Advances in chemotherapy achieved a high percentage of complete remission after primary cytostatic treatment in germinal testicular tumours. In 30-40% of patients in the IVth stage of the disease supplementary surgery is, however, necessary--retroperitoneal lymphadenectomy or metastasectomy of the lungs. The authors give an account of initial results of surgical removal of metastases in the lungs in seven patients of 48 treated with cytostatics on account of a germinal testicular tumour. The low risk of thoracotomy, if correctly indicated, justifies us to describe this operation not only as auxiliary but therapeutic.

Adolescent↗