Orientational tuning of visual cortex neurons to different stimulus intensities in the cat

The orientation tuning of field 17 neurons of the visual cortex was studied in immobilized and unanesthetized cats under different intensities of test light slits and constant light background. Orientation tuning of five neurons was invariant to stimulus intensity: their preferential orientation did not change. Thirteen cells were variable as during the change of the contrast they showed a statistically significant displacement of orientation tuning from 22 degrees to 90 degrees. Changes in other neurons were not significant. Invariant neurons differed from variable ones in several characteristics. The mechanisms of orientation tuning changes during contrast variations are discussed.     

Device for measuring paw edema in rats and mice

An unsophisticated highly precise mercuric electron-mechanic oncometer is proposed. It is intended for measuring paw edema in small laboratory animals during screening of new antiphlogistics. The device consists of two communicating vessels. The change in the mercury level after paw immersion transforms to the electrical signal by the induction technique. The controller of the displacement consists of a float, a ferromagnetic rod and a coil with windings. The movement of the rod changes mutual induction of the windings, amplitude modulation of the carrier frequency of the generator and unbalance of the differential diode bridge. The magnitude of the unbalance is recorded with the aid of appropriate units.     

The problem of indexation of left ventricular myocardial mass by body size in obese patients

AIM: To assess efficacy of different ECG-criteria of left ventricular myocardial hypertrophy (LVH) in hypertensive patients as regards body mass (obesity). MATERIAL AND METHOD: Data on 100 patients (42 males and 58 females, age 19-79 years) with diagnosis of hypertension of the first-second degree were analysed. ECG was registered in 12 leads. LVH was determined by ECG by the following criteria: Sokolov-Lion (S-L): Sv1+Rv5(v6) > 35 mm; Cornell voltage (Crn-V): R avL+Sv3 > 28 mm (> 20 mm for women); Cornell product (Crn-P). According to the body mass the patients were divided into 3 groups: with normal weight, overweight and obesity. Crn = P criterion was most sensitive in all the three groups. RESULTS: In the groups sensitivity of ECG criteria depends on several factors: on the method of indexation and on the gender and body mass index. CONCLUSION: Informative value of ECG criteria of LVH depends on the method of indexation and on the amount of the excessive body mass.     

Dynamic changes in the tuning of striate neurons to the shapes of cross-shaped figures

Time slice analysis was used to study the dynamics of tuning to the shapes of cross-shaped figures flashing in the receptive fields of 83 neurons in the primary visual cortex (field 17) of the cat brain. Tuning was assessed in terms of the numbers of spikes in the overall response and its sequential 20-msec fragments. Only 11.7% of neurons produced reproducibly developing spike responses to a given shape (defined as the angle between the lines), i.e., had a preferred cross-shaped figure. In the remaining cases (88.3%), tuning of neurons to the shape of the cross showed dynamic changes. In 7.2% of cases, changes in the preferred shape of the cross occurred monophasically; changes were biphasic in 27.0% of cases, while in the remaining 54.1% of cases, the dynamics in changes in the preferred cross shape were undulatory. The tuning of receptive field zones is assessed as the cause of these effects and their difference from the previously observed dynamics of preferred orientations of single bars and cross-shaped figures; the functional significance of these effects is also discussed.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 89, No. 10, pp. 1216–1225, October, 2003.     

The optimization of techniques complex of serologic diagnostics of connective tissue systemic diseases

The connective tissue systemic diseases originate from pathologic process following with antinuclear antibodies emergence. To detect these antibodies a significant number of diagnostic tests and techniques has been applied. Besides that, there is no conventional algorithm of antinuclear antibodies diagnostic. To detect antinuclear antibodies a two-fold diagnostic algorithm was applied In the capacity of screening techniques the indirect immunofluorescence technique was applied to the cells of line Hep-2 (antinuclear factor) and detection of antibodies to extractable nuclear antigen. The second stage of diagnostic included the detection of content of more specific antinuclear antibodies using the Lineblott method and the double-helical DNA antibodies. The blood serum from 981 patients with suspected connective tissue systemic diseases, 115 patients with systemic lupus erythematous and 57 healthy individuals was analyzed. The levels of antinuclear factor, nuclear antigen antibodies and double-helical DNA antibodies were detected. The antinuclear factor was detected in 84% and 86% of cases, double-helical DNA antibodies in 55% and 39% of cases depending of reagents using in detecting these characteristics. Among healthy individuals, antinuclear factor was detected in 5% (1/20) of blood serum samples in titers less than 1:160. In the group of patients with suspected connective tissue systemic diseases, antinuclear factor was detected in 48% (474/981) of cases and extractable nuclear antigen in 20% (326/981) of cases. The Lineblott test was positive in 33% (326/981) of patients with suspected connective tissue systemic diseases. Among antinuclear factor positive patients nuclear antigen antibodies were detected in 36% (171/474) and the Lineblott test was positive in 63% (298/474) of cases. Among antinuclear factor negative patients but positive under anti-nuclear antigen identification, the Lineblott test was positive in 6% (28/507) of cases. The two-fold algorithm of nuclear antigen testing is an effective technique to be applied in the clinical diagnostic laboratory. The results of effectiveness of this algorithm demonstrated that this method can ensure 33% of cost savings of testing individuals with higher incidence of diseases.     

Verotoxin as a major laboratory criterion for Escherichia coli O157-induced enteric infection complicated by hemolytic uremic syndrome in infants in the Omsk region

The paper presents the results of etiological interpretation of the outbreak of Escherichia coli O157-induced enteric infection complicated by hemolytic uremic syndrome in Omsk in spring 2009. Seventeen infants aged 5 months to 2.5 years were examined; of them 9 patients were on hemodialysis. The diagnosis was verified in 7 children, by isolating verotoxin after fecal enrichment on the concentrating nutrient RIDA Enrichment Bouillon medium containing bile salts and mitomycin C, E. coli O157:H7 cultures on the sorbitol medium and/or by identifying E. coli O157 DNA. Six (4 having verotoxin) infants were found to have rotavirus and noro-virus antigens or DNA/RNA, which may make a contribution into the development of mixed infection and increase the risk of complications.     

Effects of middle-ear surgical interventions of different types on peripheral audio reproduction part of the acoustic analyzer in patients with otitis media purulenta chronica

Different operations on the middle ear were performed in 86 patients with otitis media purulenta chronica (OMPC). Mean bone hearing thresholds in the high-pitched area (10,000-16,000 Hz) were determined and suprathreshold tests were made in 86 patients on day 10 and 6 months after surgery. Minimal changes seen only in early postoperative period occurred in canal wall up operations with tympanoplasty of type I-II. Canal wall down type of surgery had a negative effect on the function of the cochlear receptor system in the early postoperative period. All "open" types of ear surgery, even with tympanoplasty, provoked hearing deterioration with maximum elevation of the hearing thresholds in the high-pitched area (10,000-16,000 Hz). Middle ear surgery without forming a new tympanic cavity results in progressive deterioration of the peripheral part of the hearing receptor system.