Characteristics and mechanisms of the interhemisphere synchronization in the rat motor cortex

Synchronised activity of the callosal cells was studied in the rat motor cortex. Cross-correlation analysis revealed narrow symmetrical peaks (less than 20 ms) and intermediate ones (30-80 ms). Common neuron(s) located in one hemisphere reciprocally connected callosal cells can play the role of a "common input" that synchronises discharges of the cells in both hemispheres. The narrow and intermediate peaks seem to be mediated by mono- and polysynaptic connections, resp.     

American military dentists as prisoners-of-war in the Pacific theatre during World War II

Fifty-three American Military dentists were held by the Japanese as Prisoners-of-War during World War II. Throughout 40 months of captivity these men served their fellow prisoners providing dental treatment in an austere environment with "jury-rigged" equipment and supplies. A brief overview of their experiences is presented in this paper.     

Combustion chemistry of ternary blends of hydrogen and C<Subscript>1</Subscript>–C<Subscript>4</Subscript> hydrocarbons at atmospheric pressure

Interest in the combustion chemistry of multifuel blends is motivated by the need to study the combustion of natural gas, which is known to be a mixture of alkanes. The present study performed using molecular beam mass spectrometry and numerical modeling has shown that the width of the zones of hydrogen and methane consumption in the H₂/CH₄/C₃H₈/O₂/Ar flame and the width of the zones of methane and propane consumption in the CH₄/C₃H₈/C₄H₁₀/O₂/Ar flame differ significantly from each other. The causes of this phenomenon were determined by analyzing the modeling results. It has been found that in the presence of heavier compounds, lighter fuels, such as H₂ and CH₄, are formed, which reduces the total rate of their consumption and, hence expands the zone of their consumption in the flame. The influence of the presence of hydrogen in the fuel mixture on the concentration of C₂ hydrocarbons has also been studied. It has been established that the addition of hydrogen reduces the maximum concentration of ethane, ethylene, and acetylene in the flame, and the fraction of unsaturated C₂ hydrocarbons with respect to saturated ones also decreases.     

Parameter constraints in a theoretical model for trial-body motion in a satellite experiment designed to refine the gravitational constant

Constraints are analyzed for a model for the relative motion of trial bodies interacting gravitationally in a satellite, which lead to a given low level of systematic error and enable one to refine the gravitational constant by two orders of magnitude by measuring the relative motion. Constraints are considered that are related to ignoring relativistic corrections in describing the Earth's gravitational field and neglecting zonal harmonics in the expansion of the Earth's gravitational potential above a certain harmonic number and also neglecting the effects from the lunar and solar tidal potentials.Translated from Izmeritel'naya Tekhnika, No. 12, pp. 3–6, December, 1993.     

Gastrojejunostomy in proximal resection of the stomach

Correlations between specific binding of labeled adrenoligands in the frontal cortex and hypothalamus and peripheral blood plasma testosterone were studied in BALB/cLac, CBA/Lac, and S57BL/6J male mice. A negative correlation was detected between blood testosterone and the extent of specific binding of 3H-clonidine, a 1.6 nM alpha 2-adrenoceptor agonist, in the hypothalamus. No correlations were revealed between specific binding of 3H-clonidine in the frontal cortex and binding of the rest radioligands (0.4 nM alpha 1-adrenoceptor antagonist 3H-prazosin and 1.6 nM beta-adrenoceptor antagonist 3H-dihydroalprenolol) in both brain segments and blood testosterone level. Further experiments in six mouse strains (A/He, BALB/cLac, CBA/Lac, C57BL/6J, DD, and YT) revealed a reliable negative genotypic correlation between hypothalamic maximal specific binding of 3H-clonidine and testosterone level. The detected feedback may be an important regulatory mechanism of the hypothalamo-hypophyseo-gonadal system in male mice.     

Long-term atrovent treatment of chronic obstructive bronchitis

AIM: The study of effects of long-term ipratropium bromide on the course of chronic obstructive bronchitis. MATERIALS AND METHODS: A 3-month atrovent monotherapy (3-6 doses daily) was performed in 19 patients with verified chronic obstructive bronchitis of moderate severity. Monitoring consisted of symptoms registration, pickflowmetry (two times a day), external respiration measurements. RESULTS: Atropen produced a positive trend in all the clinical symptoms, course of viral infections, exercise tolerance, bronchial permeability, respiratory capacity. The highest atrovent efficacy was recorded in patients with chronic bronchitis of smokers and chronic bronchitis in tracheobronchial diskinesia. No side effects were observed. CONCLUSION: Basic atrovent monotherapy modifies the course of chronic obstructive bronchitis and can be recommended for secondary prophylaxis of this disease.     

Microbiological examination of bandage soft contact lenses used in laser refractive surgery

BACKGROUND: Disposable soft contact lenses are known to be colonized by bacteria and play a key role in bacterial keratitis pathogenesis. Such lenses, commonly used after laser refractive surgery procedures in which postoperative corneal infiltrations are sometimes observed, are potentially a substrate for bacterial inoculation. This study evaluates the extent of such a contamination. METHODS: Sixty disposable lenses collected from 60 eyes of patients who underwent photorefractive keratectomy (PRK), photoastigmatic refractive keratectomy (PARK), or laser in situ keratomileusis (LASIK) for the treatment of myopia or hyperopia were collected under sterile conditions over 4 months and cultured in various media. Results were statistically analyzed and the correlation with clinical and epidemiological data was examined. RESULTS: Eleven (18.3%) of the examined lenses were contaminated with Staphylococcus epidermidis. No other bacteria or fungi were found. Contamination was significantly more common among female patients (P = .036). Correlation with the other clinical or operative parameters examined was statistically insignificant. CONCLUSIONS: Contamination was independent of the surgical procedure and females who were frequent users of eyelid cosmetics displayed higher contamination frequencies, suggesting that bacteria possibly originate from eyelid flora. The isolation of Staphylococcus epidermidis requires close postoperative surveillance, since it is a known cause of keratitis. Prophylactic postoperative treatment with tobramycin, gentamycin, or sulphonamides could be indicated.     

Radiofrequency catheter ablation of an incessant supraventricular tachycardia initiated by a Hisian parasystole

The coexistence of a parasystolic focus, tachycardia dependent right bundle branch aberrancy, and an AV accessory pathway is reported here. This condition was present in a 40-year-old man, which led to an incessant AV reciprocating tachycardia. Further electrophysiological study revealed that the parasystolic focus was located somewhere in the His bundle; endocardial mapping disclosed a right posterior accessory pathway. Radiofrequency current was delivered at the atrial level of the right posterolateral AV groove and successfully ablated the accessory pathway, leading to a dramatic improvement in cardiac function. In conclusion, the recognition of the electrophysiological mechanism of incessant supraventricular tachycardia was of crucial importance for the therapy decision. A definitive intervention using radiofrequency catheter ablation should be considered early and not postponed in patients with tachycardia-induced cardiomyopathy.