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Biomedical subjects

S N Novikov

Publications and source records attributed to S N Novikov.

At least 19 recordsLinked to original sources
PubMed2004

Mn interstitial diffusion in (ga,mn)as.

We present a combined theoretical and experimental study of the ferromagnetic semiconductor (Ga,Mn)As which explains the remarkably large changes observed on low-temperature annealing. Careful control of the annealing conditions allows us to obtain samples with ferromagnetic transition temperatures up to 159 K. Ab initio calculations, in situ Auger spectroscopy, and resistivity measurements during annealing show that the observed changes are due to out diffusion of Mn interstitials towards the surface, governed by an energy barrier of 0.7-0.8 eV. Electric fields induced by Mn acceptors have a significant effect on the diffusion.

Journal Article↗
PubMed2004

[Methodology of bone marrow imaging in diagnosis of skeletal metastatic involvement in cancer patients].

The cost-effectiveness of visualization techniques for the entire hemopoietic bone marrow (BM) in diagnosis of tumor involvement of the skeleton was evaluated in 1,200 cancer patients. BM involvement was diagnosed in 199. Generalized involvement detectable by imaging any skeletal region was reported in 72 (31.6%) patients. Focal BM involvement was registered in 127 (68.4%): pelvis--51, femur--29, sternum--25, cervical or sternal region--25 and lumbar--15. When pelvis, sternum, femur and cervico-thoracic spine were imaged, tumors were detected in 90%, 3 regions--62.3-80.1%, 2--50.5-71.1% and 1--38.2-54.6%.

Adult↗
PubMed2002

[Clinical course and treatment of Hodgkin's disease with concomitant bone marrow lesions].

Fifty patients with confirmed local multiple lesions of bone marrow were selected by 99mTc scintigraphy, magnetic resonance imaging and morphologically-supported trepan biopsy from 155 cases of Hodgkin's disease stage II-IVAB. Bone marrow lesions were relatively more common in younger patients 1-11 months after primary tumor detection (an average of 6.5 months). They were detected within 12-156 months (an average of 48 months) among relapsing patients with nodal sclerosis and mixed-cell tumors stage III-IVAB, mostly concomitant with anemia and lymphopenia. Standard combination chemotherapeutical regimens for primary patients (MOPP, ABVD and LOPP) and relapsing ones (CCNU-OPP and ABVD) were effective in those with bone marrow lesions. Side-effects (myelodepression) did not exceed normal levels, provided human recombinant interleukin-1 beta (beta-leukin) was administered for protection and leukopoietic stimulation.

Adolescent↗
PubMed2002

[The role of indirect lower lymphoscintigraphy for radiotherapy planning in Hodgkin's lymphoma].

The feasibility of application of indirect lower lymphoscintigraphy (ILLSG) was assessed in 202 patients with Hodgkin's disease. Its high diagnostic potential was demonstrated by comparison with direct X-ray contrast lymphography: ILLSG's sensitivity was 91.5%, specificity--76.1% and overall accuracy--88.4%. The procedure used for topometric preparation prior to exposure of paraaortal and ileaco-inguinal lymph nodes proved instrumental in designing individual irradiation fields: their boundaries were altered in 21.6% on the basis of ILLSG data.

Feasibility Studies↗
PubMed2002

[Role of radionuclide imaging of bone marrow and spleen in choice of therapy and topometric preparation for radiotherapy of patients with Hodgkin disease].

Use of radionuclide methods of bone marrow (BM) and spleen visualization was assessed in 176 patients with primary Hodgkin's disease and 116 relapsing cases. The study was intended to help design treatment modality and carry out topometric measurements for exposure to radiation. Stage of tumor was revised in 19 primary patients as a result of BM scintigraphy, and this factor was responsible for major changes in the treatment modality in 11 patients (6.2%). This factor played a similar role in designing irradiation field boundaries in another 18 primary patients (10.2%). Similarly, the choice of treatment modality was revised in 33 relapsing patients (27.5%). The standard roentgenometric data on the anatomical reference points of the spleen and those of radionuclide-assisted visualization were compared in 37 patients. In 17 (45.9%), part of the spleen was shown by scintigraphy to be outside the irradiation boundaries delineated by the roentgenometric procedure. Roentgenometry located the spleen well inside the irradiation fields in 8 patients (21.6%). However, due to scintigraphy, their boundaries were altered to cut down the exposure of the left kidney (5) or the left lung (3). Complete agreement between roentgenometric and scintigraphic measurements were reported in 12 patients (32.4%) only.

Bone Marrow↗
PubMed2001

[Risk factors for bone marrow involvement in Hodgkin's disease].

The significant factors of risk for bone marrow involvement in Hodgkin's disease included age over 40 yrs, such unfavorable histological features as lymphoid exhaustion and nodular sclerosing stage II, symptoms of intoxication, an ESR of more than 50 mm/h, increased fibrinogen (> 5.0 g/l), blood-plasma alkaline phosphatase (> 130 units), leukocyte concentration (> 10,000 per min) and decreased hemoglobulin (< 100 g/l). Despite the reliable correlation between bone marrow involvement and said factors, relevant data did not provide a similarly reliable basis for accurate prognosis of tumor dissemination. However, our findings pointed to two categories of Hodgkin's disease patients characterized by minimal risk of tumor dissemination--patients under 20, with stage I-II AB and IIIA tumors,--and patients with similar tumors and such favorable histological patterns of major pathology as high lymphocytic ratio and nodular sclerosing stage I.

Adult↗
PubMed2001

[The problem of restoring bone marrow, irradiated during radiotherapy of Hodgkin's disease patients].

The results of bone marrow (BM) visualisation of 663 irradiated regions were analysed. In all cases BM absorbed doses varied between 10-40 Gy. Active accumulation of 99mTc-colloids was observed in 48 out of 60 regions irradiated within 20 Gy. This pattern proved the possibility of effective and rapid hematopoietic regeneration after low-dose radiotherapy. On the contrary, during the first 6 months after BM irradiation with doses over 25 Gy we detected prominent depression of tracer uptake in 86.2% of all regions. It was shown that intensity of BM regeneration reached its peak during the second half-year after irradiation within 25-40 Gy. BM recovery during this period was dose dependent and was detected in 47.7% areas irradiated with 30 Gy and 24.7%--with 40 Gy. Regression analysis revealed significant correlation of postradiotherapy hematopoietic status with the value of BM absorbed dose and the time after the end of radiotherapy. Scintigraphic patterns of BM regeneration were registered in 69 of 89 (77.5%) regions irradiated within 25-30 Gy and only in 96 out of 231 (41.6%)--within 35-40 Gy.

Bone Marrow↗
PubMed2001

[Post-radiation compensatory peripheral expansion of hemopoiesis in Hodgkin's disease patients].

Development of peripheral expansion (PE) of hematopoiesis provides a basic mechanism of compensation for radiation-related damage to the bone marrow (BM) in radiation-treated patients with Hodgkin's disease. Radio nuclide visualization of BM established a significant correlation between PE degree and extent of BM damage. Among other things, it was found that hematopoiesis PE does not increase significantly until 35% of BM is involved and not until 12-24 months after radiotherapy; after 25 months and later, PE starts to subside. In patients under the age of 15, PE was triggered on at an earlier stage than in adults (within the first 12 months) and there was no correlation between the volume of exposed.

Adolescent↗
PubMed2001

[Comparative analysis of data from trepanobiopsy and radionuclide visualization of bone marrow].

Scintigraphy of the bone marrow was tested as a noninvasive procedure of hemopoiesis evaluation in 79 cancer patients. Scintigraphy and trepanobiopsy of the marrow of iliac bones were carried out in all patients. The results matched in 88.6% (70 out of 79) pointing to a significant correlation (p < 0.01). A similar correlation (p < 0.05) (80% matching) was observed in cases of irradiation of ilioinguinal nodes. Besides, the coefficient of correlation of the data of quantitative and semiquantitative analysis of marrow scintigraphs was 0.7725 (p < 0.01). To summarize, the significant correlation between the findings of scintigraphic and morphological examination pointed to the potential of the former as an noninvasive procedure for evaluation of hemopoiesis.

Biopsy↗
PubMed2000

[Role of bone marrow scintigraphy in defining the therapeutic approach for some malignant tumors in children] .

The data on scintigraphic examinations of the bone marrow (BM) carried out in 76 patients, aged 2-16, are evaluated. Focal, multi-focal and diffuse lesions were identified. Metastases to BM were detected in 6 out of 28 (21%) patients with Hodgkin's disease. Scintigraphic evidence played a role in working out treatment modalities in 4 cases. Metastatic foci located outside primary tumor were detected in 3 out of 26 (11.5%) patients with Ewing's sarcoma and scintigraphic findings were considered in all 3 cases when scope of radiotherapy and chemotherapy intensity were elaborated. Also, lesions to BM were found in 9 out of 22 (41%) patients with neuroblastoma. Radiotherapy was ruled out in 4 cases of multi-focal and diffuse lesions while all 5 patients with focal ones received it.

Adolescent↗
PubMed2000

[Comparison of diagnostic significance of bone and bone marrow scintigraphy in patients with Hodgkin disease].

Diagnosis of skeletal tumors in patients with Hodgkin's disease is of paramount importance for precise staging of tumor process, prognosis and choice of optimal treatment. At present, according to the International Union Against Cancer (UICC), scintigraphy of bones and bone marrow is not regarded as a standard examination procedure for this pathology. We believe, however, that the sensitivity, specificity and overall accuracy of this procedure for bone marrow examination are 91.4; 94.8 and 92.9%, while those of osteoscintigraphy--49.1; 97 and 80.6%, respectively. According to our statistics (based on chi-square-test), the sensitivity and overall accuracy of osteoscintigraphy were significantly lower (p < 0.05) than those of bone marrow scintigraphy. The specificity (100%) of bone marrow trepanobiopsy is beyond doubt. However its sensitivity (36%) and overall accuracy (70.7%) were significantly lower (p < 0.05) than those of bone marrow scintigraphy (based on chi-square-test). Therefore, since the results of bone marrow scintigraphy are comparable to those of MRT which, like bone marrow trepanobiopsy, is a component of the diagnostic standard procedure approved by the UICC, bone marrow scintigraphy should be recommended for assaying the extent of involvement in Hodgkin's disease.

Adult↗
PubMed1997

[Experience with low-field magnetic resonance tomography for the diagnosis of bone marrow lesions].

Metastatic lesions of the bone marrow (BM) in cancer patients are instrumental in making prognosis and selecting optimal treatment modality. Recent evidence has pointed to insufficient sensitivity of morphological, X-ray and osteoscintigraphic diagnostic procedures to deal with focal alterations in BM. Vistas in application of low-field magnetic resonance tomography for detection and differential diagnosis of localized lesions in BM are discussed.

Adolescent↗
PubMed1997

[Clinical experience of bone marrow scintigraphy in cancer patients].

129 patients with various malignant tumors and 10 persons from the control group were examined by BM scintigraphy with radio-colloids. The following scintigraphic signs were associated with neoplastic bone marrow pathology: 32 patients with BM metastasis had focal or multifocal defects on BM scans, 8-localized areas of increased tracer accumulation ("hot spots"), 5-diffusely diminished tracer uptake. There were no correlations between survival and grade of peripheral expansion of tracer uptake (scintigraphic sign of hematopoietic peripheral expansion) and the probability of bone marrow BM involvement by tumor cells.

Adolescent↗
PubMed1993

The genetics of pheromonally mediated intermale aggression in mice: current status and prospects of the model.

A genetic model of pheromonally mediated aggression in laboratory male mice, which has been developed over the past decade, is reviewed and integrated with recent developments in the neurobiology of olfaction and the chemistry of pheromones in Mus musculus. Experimental data strongly support the possibility of enzymatic activation of aggression promoting and inhibiting pheromones by beta-glucuronidase (EC 3.2.1.31). These findings introduce important questions as to the involvement of beta-GLU genes (Gus and Eg on chromosomes 5 and 8, respectively) in the determination of urine odor profiling. The discovery of two neuroanatomically, and functionally distinct, olfactory structures in 1975 led the way for direct selection of olfactory bulb relay neurons, medial amygdala nucleus neurons and TIDA-neurons for analysis of the genetic mechanisms involved in pheromonal action on aggressive and other olfactory mediated social behaviors in rodents.

Aggression↗
PubMed1989

[Corticosteroid response and indolamine content of the mouse brain under the action of a pheromone, disrupting spermatogenesis].

The volatile components of adult male urine from laboratory mice of CBA/LacSto strain inhibited spermatogenesis in CBAB6F1 30-day old mice. There were no significant responses in hypothalamic and olfactory bulb indolamine systems, neither in the blood corticosterone level of the mice during experimental treatment. A prolactin mechanism of the pheromone inhibition of testicular function is suggested.

Animals↗