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Biomedical subjects

A A Nikonov

Publications and source records attributed to A A Nikonov.

At least 19 recordsLinked to original sources
PubMed2002

[Differential diagnostic criteria of lateral amyotrophic sclerosis].

Differential diagnostic criteria of lateral amyotrophic sclerosis (LAS) and lateral amyotrophic sclerosis syndrome were elaborated on the basis of complex investigation, including EMG and blood plasma trace element analysis. Fifty-two patients (25 with LAS, 27 with LAS syndrome) have been examined, the diagnoses being established according to the World Neurologist Federation criteria. LAS syndrome was stipulated by a vascular spinal cord lesion-discircular myelopathy; in some cases vascular deficit was combined with an inherent narrowness of spinal cord channel. All patients were followed-up with a 6-month interval. The results of the study allow to differentiate LAS and LAS syndrome of vascular genesis, already during the first medical examination.

Aged↗
PubMed2001

A photoaffinity-labeled green leaf volatile compound 'tricks' highly selective and sensitive insect olfactory receptor neurons.

The sex pheromone of the scarab beetle, Phyllopertha diversa, is emitted by females and specifically detected by olfactory receptor neurons in the male and female antennae. Single sensillum recordings showed that, in contrast to the less sensitive pheromone sensilla in females, olfactory receptor neurons in the male antennae had a low threshold (1 ng), which rivals those of moths. The male and female antennae also possessed olfactory receptor neurons specific for the detection of floral and green leaf volatile compounds. Detectors for the green leaf volatile (Z)-3-hexenyl acetate had a threshold (10 pg) far below the sensitivity of the pheromone-detecting machinery. In addition, these neurons showed a remarkable selectivity even when challenged with related compounds at 10000-fold higher concentrations. Surprisingly, a diazo analog, (Z)-3-hexenyl diazoacetate, elicited slightly higher nervous activity than the natural ligand in the neurons specific and selective for (Z)-3-hexenyl acetate. The inability of the green leaf volatile-detecting machinery to discriminate the photoaffinity-labeled compound from the natural product indicates that the synthetic ligand interacts with odorant-binding protein, odorant receptor and odorant-degrading enzyme as does the cognate ligand.

Acetates↗
PubMed2001

Electrophysiological evidence for a chemotopy of biologically relevant odors in the olfactory bulb of the channel catfish.

Extracellular electrophysiological recordings from single olfactory bulb (OB) neurons in the channel catfish, Ictalurus punctatus, indicated that the OB is divided into different functional zones, each processing a specific class of biologically relevant odor. Different OB regions responded preferentially at slightly above threshold to either a mixture of 1) bile salts (10(-7) to 10(-5) M Na(+) salts of taurocholic, lithocholic, and taurolithocholic acids), 2) nucleotides [10(-6) to 10(-4) M adenosine-5'-triphosphate (ATP), inosine-5'-monophosphate (IMP), and inosine-5'-triphosphate (ITP)], or 3) amino acids (10(-6) to 10(-4)M L-alanine, L-methionine, L-arginine, and L-glutamate). Excitatory responses to bile salts were observed primarily in a thin, medial strip in both the dorsal (100-450 microm) and ventral (900-1,200 microm) OB. Excitatory responses to nucleotides were obtained primarily from dorsal, caudolateral OB, whereas excitatory responses to amino acids occurred more rostrally in the dorsolateral OB, but continued more medially in the ventral OB. The chemotopy within the channel catfish OB is more comparable to that previously described by optical imaging studies in zebrafish than by field potential studies in salmonids. The present results are consistent with recent studies, suggesting that the specific spatial organization of output neurons in the OB is necessary for the quality coding/decoding of olfactory information.

Amino Acids↗
PubMed1998

[Relaparotomy].

For a period of 1987-1995 yrs. the operations on a peritoneal cavity organs were performed in 14,718 patients. In 87 reoperated patients 93 relaparotomies were conducted. After relaparotomy 36 (41.3%) patients died.

Gastrointestinal Diseases↗
PubMed1998

[Treatment of vertigo with betaserk in patients with vascular and traumatic cerebral injuries].

42 patients with discirculatory and posttraumatic encephalopathy were treated with betaserk. Ultrasonic dopplerography and acoustic evoked potentials were used for assessment of the treatment results. It was established that betaserk was quite effective both for arrest of acute vertigo attacks and for prophylaxis of vertigo relapses. A decrease in frequency of vertigo attacks (by 60%, on the average) as well as in their duration and intensity were accompanied by an increase in blood flow through the arteries of vertebro-basilar system and by normalization of the parameters of acoustic evoked potentials.

Arterial Occlusive Diseases↗
PubMed1993

[The use of NMR tomography for the dynamic observation of patients with disseminated sclerosis].

NMR-tomography data and clinical topographic parallels were followed up in 27 multiple sclerosis patients on treatment. Primary NMR tomography identified disseminated foci of more intensive signal in the brain and spinal cord of 78% of the patients. In 6 patients the diagnosis was not confirmed, in 21 patients there was tomographic evidence of various disorders: foci of hyperintensity associated with ventricular system enlargement, cerebral atrophy, hyperintensity zones. The number of more intensive signal foci correlated with the disease severity. Hemispheric foci of hyperintensity were clinically most important. Most of the foci were localized in periventricular region. Changes in the above parameters were observed only 1-2 years after the treatment. It is inferred that NMR tomography is both diagnostic and follow-up tool in multiple sclerosis.

Adult↗
PubMed1991

[Primary nodular lymphosarcoma of the breast].

A case of primary breast lymphosarcoma with axillary lymph node involvement and a local relapse after radical mastectomy has been described. The patient was a 43-year-old woman. Histologically, the primary tumour showed nodular (follicular) growth of prolymphocytes (centrocytes) and lymphoblasts (centroblasts) whereas the lymph node involved and relapsed tumour were characterized by diffuse proliferation of lymphoblasts (centroblasts). Immunocytochemistry revealed B-lymphocytic nature of the tumour cells. There were some difficulties in histological interpretation of this tumour due to both artificial structures and so-called lymphoepithelial lesions--remnants of ductal and lobular structures in the tumour tissue. The follicular type of growth of the primary breast lymphosarcoma is not in concordance with the current concept of histogenesis of the mucosa-associated lymphoid tissue lymphomas.

Adult↗
PubMed1990

[Discrepancies in the histological diagnosis of hyperplastic states and cancerous pathology of the endometrium].

Two hundred and seventy-two scrapings of the endometrium and histologic sections of seven removed uteri obtained from 30 hospitals of Leningrad were reviewed at the pathology departments of the Institute and Oncologic Dispensary. Disagreement in diagnostic conclusions (malignancy, border-line condition, other pathology or normal tissue) was registered in 51%. Disagreement ranged from 15% (hydatidiform mole) to 71% (atypical hyperplasia of the endometrium). The extent of disagreement between staff members of the two medical establishments and that between the said specialists and other consultants was of the same order.

Biopsy↗