Effect of ageing on the regulation of motor unit force in rat medial gastrocnemius muscle

The influence of ageing on the regulation of force through the firing rate (force-frequency relationship) and motor unit contractile output were investigated in three types of motor unit (MU): FF, FR and S, in the medial gastrocnemius muscle. A control group of young (5-10 months) Wistar rats was compared to three groups of older (20-21, 24-25 and 28-30 months) animals. The optimal tetanus characterized by the maximum contractile output (force-time area - FTA - per single pulse) was determined. During ageing, the steep part of the force-frequency relationship of medial gastrocnemius MUs shifted towards lower stimulation rates. However, in all MU types of the oldest rats, the opposite shift (towards higher rates) was observed. Ageing induced a substantial increase in the maximal FTA per pulse, particularly in S and FF units, but only subtly altered the fusion index of the optimal tetanus of MUs. Moreover, a transient increase in the mean forces of FF MUs was revealed in the groups of 20-21 and 24-25 months rats, and a significant decrease in the fatigue resistance of FR MUs accompanied ageing. These findings increase our understanding of the functional mechanisms responsible for changes in rate coding and alterations in muscle fatigability during ageing.     

Expression of extracellular matrix metalloproteinase (MMP-9), E-cadherin and proliferation-associated antigen Ki-67 and their reciprocal correlation in canine mammary adenocarcinomas

BACKGROUND: The purpose of the present study was to determine the expression of the proteins related to tumour metastatic potential, including matrix metalloproteinase (MMP)-9 and E-cadherin, in correlation with the expression of proliferation-associated antigen (Ki-67) in canine mammary adenocarcinomas. MATERIALS AND METHODS: Material for the studies was obtained during surgery from 35 dogs of various breeds, aged 7 to 16 years. Neoplastic tumours were verified by a pathologist. The studied proteins were detected by immunohistochemical reactions. The microphotographs of the studied tumours were subjected to computer-assisted image analysis using MultiScaneBase V 14.02 software. RESULTS: Expression of MMP-9 was noted in almost 83% of the tumours, expression of E-cadherin in 77% of tumours, while expression of Ki-67 antigen was detected in fewer than 26% of studied tumours. CONCLUSION: The positive correlation (r=0.375) between expressions of MMP-9 and Ki-67 and negative correlations between E-cadherin and Ki-67 (r=-0.383) as well as between MMP-9 and E-cadherin (r=-0.45) could suggest that expression and biological significance of the studied markers in mammary adenocarcinomas in dogs resembles the pattern noted in ductal carcinoma, i.e. in the most frequent histological type of malignant tumour in humans. This may point to suitability of the animal model in studies on mechanism of neoplasia and metastases in humans.     

Sequences homologous to ribosomal insertions occur in the Drosophila genome outside the nucleolus organizer

Many repeating units of Drosophila melanogaster rDNA contain a DNA sequence within the gene for 28S rRNA that does not code for rRNA. This sequence has been called the ribosomal insertion [Wellauer, P. K. & Dawid, I. B. (1977) Cell 10, 193-212]. We report here that members of the same sequence family occur outside the ribosomal locus. "Non-rDNA insertion DNA" was separated from rDNA by density gradient centrifugation, and sequences homologous to the ribosomal insertion were detected by hybridization with restriction endonuclease fragments derived from a cloned rDNA repeating unit. Pure insertion sequences from cloned rDNA separated from main band DNA and behaved like a component with high G + C content. Non-rDNA components hybridizing to the insertion also separated from main band DNA but less so than pure insertion sequences, suggesting that non-rDNA insertion sequences are linked to DNA of different nucleotide composition. Restriction endonuclease analysis of non-rDNA insertion DNA showed many fragments of different sizes. The patterns obtained were similar in embryonic, larval, pupal, and adult DNA and DNA from cultured cells (Schneider cell line 3). Non-rDNA insertion sequences account for about 0.2% of the genome or about 400 kbases of DNA per haploid complement.     

In-vitro immunomodulatory effects of haloperidol and perazine in schizophrenia.

There are some reports describing concurrent changes in lymphocytic and monocytic activities in schizophrenia. In this study we investigated T cell activity in schizophrenic patients by measuring the release of interleukin-2 (IL-2) and soluble interleukin-2 receptor (sIL-2R) by T cells and the percentages of CD4+ and CD8+ cells in blood. The release of IL-2 and sIL-2R by T cells was evaluated in dilute whole blood after in-vitro stimulation with phytohemagglutinin. IL-2 levels and the percentage of CD4-cells tended to decrease and sIL-2R levels decreased significantly in schizophrenic patients. Haloperidol and perazine significantly decreased IL-2 levels and increased sIL-2R levels and the percentage CD4-cells. IL-2 and sIL-2R levels were lower in patients with a predominance of positive symptoms. The neuroleptic-induced increase in sIL-2R levels was higher in patients with a predominance of positive symptoms compared with those in whom both positive and negative symptoms were severe. The study has shown that T-cell activity is reduced in schizophrenia and that neuroleptics may have immunomodulatory properties.     

Analysis of Tool Geometry for the Stamping Process of Large-Size Car Body Components Using a 3D Optical Measurement System

The paper presents a method for checking the geometry of stamped car body parts using a 3D optical measurement system. The analysis focuses on the first forming operation due to the deformation and material flow associated with stall thresholds. An essential element of the analysis is determining the actual gap occurring between the forming surfaces based on the die and punch geometry used in the first stamping operation. The geometry of car body elements at individual production stages was analyzed using an optical laser scanner. The control carried out in this way allowed one to correctly position the tools (punch and die), thus introducing the correction of technological parameters, having a fundamental influence on the specific features of the final product. This type of approach has not been used before to calibrate the technological line and setting of shaping tools. The influence of the manufactured product geometry in intermediate operations on the final geometry features was not investigated.     

High-Performance Method of Recovery of Metals from EAF Dust—Processing without Solid Waste

A highly effective method of the processing of steelmaking dust in an arc-resistant furnace has been presented. The aim of the research was to investigate the possibility of processing steelmaking dust in terms of waste minimization and selective recovery of valuable components. For this purpose, an electric arc resistance furnace was used. Granulated steelmaking dust with reducer (coal dust) was the input material. The products of the process are zinc oxide, iron alloy and slag, with properties meeting high ecological requirements. The technology does not generate solid waste. Zinc recovery is over 99% and iron recovery over 98%. The content of heavy metals (Zn + Pb + Cu) in glassy slag is below 0.2%, which ensures very low leachability.     

Plasma Levels of Cortisol,Progesterone, Oestradiol‐17β and Prostaglandin F2α Metabolite After ACTH (Synacthen Depot®) Administration in Ovariectomized Gilts

In order to elucidate the effect of stress on reproductive hormones, the present study was designed to investigate the effect of adrenocorticotropic hormone (ACTH) on the plasma levels of cortisol, progesterone, oestradiol‐17 β and prostaglandin F_2α metabolite in ovariectomized gilts. Ovariectomy and cannulation of the jugular vein were performed within 1 week of oestrous detection, under general anaesthesia. Approximately 1 week after surgery, two gilts were each administered ACTH (Synacthen Depot®) intravenously, at a dose of 0.01 mg/kg body weight, and one gilt was given saline solution (5 ml). The reverse was performed on the following day. The administration of ACTH was followed by a concomitant elevation of cortisol, progesterone and prostaglandin F_2α metabolite but not of oestradiol‐17β. Peak cortisol, progesterone and prostaglandin F_2α metabolite levels were reached at 80 ± 10.0, 80 ± 10.0 and 46.6 ± 13.3 min after ACTH administration and the durations of the peaks were 181.8 ± 19.8, 308.1 ± 49.7 and 181.8 ± 7.9 min, respectively. The total area under the curve for cortisol, progesterone and prostaglandin F_2α metabolite was significantly higher in the ACTH than in the control group. The present results indicate that during stress, cortisol, progesterone and prostaglandin F_2α levels are elevated while the level of oestradiol‐17β is less affected. It can be concluded that the administration of ACTH to ovariectomized gilts, results in the elevation of cortisol, progesterone and prostaglandin F_2α metabolite but not of oestradiol‐17β.     

Atorvastatin and fenofibric acid differentially affect the release of adipokines in the visceral and subcutaneous cultures of adipocytes that were obtained from patients with and without mixed dyslipidemia

In this study, we compared the effects of atorvastatin and fenofibric acid, which were administered alone or in combination, on the secretory function of human adipocytes that were obtained from the visceral and subcutaneous adipose tissues of 19 mixed dyslipidemic patients and 19 subjects with a normal lipid profile. The adipocytes were incubated in vitro in the presence of atorvastatin and/or fenofibric acid. The secretory function of the cells was determined using ELISA assays. The visceral adipocytes released significantly more adiponectin and IL-6 and less PAI-1 than those that were obtained from subcutaneous tissue. The levels and patterns of adipokine release differed between the patients with or without lipid abnormalities and between the adipocytes that were obtained from visceral or subcutaneous adipose tissue. The culture that contained hypolipidemic drugs resulted in the significant changes of the release of adipokines. The effects of atorvastatin and fenofibric acid on the hormonal function of human adipocytes may be, in part, responsible for the clinical efficacy of these drugs in the prevention and treatment of dyslipidemia-related cardiovascular and metabolic disorders. The study supports the concept that the pleiotropic effects of fenofibrate and atorvastatin may be, in part, a result of their impact on the secretory function of adipocytes.     

Papillary endothelial hyperplasia presenting as recurrent malignant glioma

The initial management of patients with malignant gliomas depends on accurate histologic diagnosis which, in turn, directs appropriate treatment planning. However, the diagnosis of recurrent disease is often based solely on radiological data which can occassionally be misinterpreted as showing recurrent tumor. Lack of awareness of conditions that mimic recurrent tumor and potentially confound radiological diagnosis can lead to inappropriate therapeutic decisions. We report the case of a patient whose imaging studies suggested recurrence of malignant glioma; however, surgical resection of the lesion guided by MRI scans resulted in the correct diagnosis of papillary endothelial hyperplasia and led to appropriate management of this condition that mimicked tumor recurrence. In this report, we provide a comprehensive review of this rare entity and emphasize the importance of adequately pursuing appropriate diagnostic considerations prior to making definitive treatment decisions.