Dimerization of recombinant horseradish peroxidase in a reversed micellar system

Recombinant horseradish peroxidase reactivated from E. coli inclusion bodies was studied in a reversed micellar system of AOT in octane. The ability of the recombinant enzyme, in contrast to native horseradish peroxidase, to form a dimeric structure was found. The existence of the dimer was proved by results of sedimentation analysis. Dimer/monomer ratio in the enzyme-containing micelles and dimer catalytic activity were found to depend on the substrate used (pyrogallol, guaiacol, o-dianisidine, o-phenylenediamine). Computer modelling was used to describe possible structures of the dimeric recombinant horseradish peroxidase.     

Current problems of occupational medicine in mining enterprises of the North

The article deals with causes of occupational diseases (including those due to complex factors) among miners in Far North and other regions of CIS. The authors present main principles for more healthy work conditions with considerations of climate surroundings.     

Interrelationship between differently spaced neurons in the auditory and motor zones of the cerebral cortex in cats

Multineuronal activity was studied in unrestrained cats with bundles of seven electrodes (tips dia. 50 mcm) chronically implanted in the auditory and motor cortex. Spikes of the highest and lowest amplitude were isolated from each neurogram by an amplitude discriminator. Functional connections between neurones located under different electrodes at a distance of up 540 mcm were defined by statistical dependence of the isolated spike series. In the auditory cortex, the distance at which it was possible to detect connections between high amplitude neurones (H-H) did not exceed 450 mcm, while between low amplitude neurones (L-L) it was 270 mcm. In the motor cortex, dependent relations for similar pairs of neurones (H-H) and (L-L) were found at all the studied distances up to 540 mcm. For mixed neuronal pairs (H-L and L-H) functional connections at different distances were differently expressed at various distances.     

Delayed cytogenetics effects of chronic irradiation of South Ural population

The aim of this study was to assess the referral pattern and the impact on long-term survival of postoperative radiotherapy in patients with adenocarcinoma of the endometrium stage I. This was a retrospective study performed in a regional cancer registry which covers a population of approximately 1,000,000 persons. All 724 patients registered between 1975 and 1992 in the Comprehensive Cancer Centre South, Eastern Section, The Netherlands, were analysed. All patients had received surgery as primary treatment which was performed in one of the seven community hospitals of the region. Radiotherapy was given in one regional department. All pathology reports were checked for data on tumour differentiation and myometrial invasion. Almost half the patients (45%) were referred for postoperative radiotherapy. The depth of myometrial invasion and the degree of tumour differentiation were the main factors (P < 0.0001) influencing referral for postoperative radiotherapy. The referral pattern varied between the different hospitals, but became more similar during 1985-1988, to diverge again in recent years. In patients younger than 60 years, the depth of myometrial invasion was significantly (P = 0.01) correlated with survival. In patients older than 60 years, tumour differentiation (P = 0.05) and age (P < 0.001) were correlated with survival, but not the depth of myometrial invasion. After adjustment for known prognostic factors, a survival benefit of postoperative radiotherapy could not be established. The studied group had an excess death rate over the normal Dutch female population. This excess death rate did not decrease during follow-up, as even after 10 years an excess death rate was found. A prospective randomised trial is ongoing in The Netherlands.     

Relapsing cutaneous polyarteritis nodosa associated with streptococcal infections

BACKGROUND: Polyarteritis nodosa is an aggressive, often fatal form of vasculitis associated with multi-organ involvement. Cutaneous polyarteritis nodosa is purported to be a more benign form of this disorder with involvement limited to the skin. METHODS: The identification of a female patient from childhood to adulthood documenting repeated episodes of cutaneous polyarteritis nodosa following bouts of recurrent streptococcal pharyngitis. RESULTS: Repeated bouts of streptococcal pharyngitis at ages 11, 28, and 33 years were followed by episodes of cutaneous polyarteritis nodosa, documented by histopathologic skin changes and clinical presentation, and confirmed by therapeutic management. CONCLUSIONS: Various infectious and non-infectious conditions have been linked both to the initiation and relapse of this disease. We describe a patient with recurrent episodes of cutaneous polyarteritis nodosa spanning a period of over 20 years with each episode appearing to be linked to a prior streptococcal infection.     

Computer-based smoking cessation interventions in adolescents: description, feasibility, and six-month follow-up findings

The impact of adolescent smoking cessation clinics has been disappointing due to low participation rates, high attrition, and low quit rates. This paper describes two computerized self-help adolescent smoking cessation intervention programs: 1) a program utilizing the expert system which is based on the transtheoretical model of change and 2) a popular action-oriented smoking cessation clinic program for teens which was modified for computer presentation. High participation rates in the program among 132 smokers demonstrate the high feasibility and acceptability of the programs. Quit rates of up to 20% were observed during the intervention, and an additional 30% made unsuccessful quit attempt(s). The 6-month follow-up findings indicated that adolescents were poorly prepared to maintain abstinence.