Force, speed, and oxygen consumption in thoroughbred and draft horses

Thoroughbred (TB) and draft horses (DH) have long been selected for tasks of very different intensities and force-speed relationships. To study their adaptations, we measured O2 consumption and related variables in three TB and four DH during progressive exercise tests on a level treadmill. The horses exerted a draft force of 0, 5, 10, 15, or 20% of their body weight at speeds that increased by 2 m/s every 3 min until they could not maintain that speed. We found that TB could exert the same draft forces as DH and, at each force, TB achieved about twice the speed, twice the external power, and twice the O2 consumption as DH; thus the two breeds had the same gross efficiencies. We also found maximal O2 consumption of TB to be about twice that of DH (134 vs. 72 ml . kg-1 . min-1, respectively), suggesting adaptations to high-intensity exercise. Peak efficiency was reached at lower speeds in DH than in TB, suggesting adaptations to high-force, low-speed exercise. These differences between TB and DH in force-speed and aerobic capacities and in speed for peak efficiency likely reflect different contraction velocities in locomotor muscles.     

Single- and dual-fractal analysis of hybridization binding kinetics: biosensor applications

The diffusion-limited hybridization kinetics of analyte in solution to a receptor immobilized on a biosensor or immunosensor surface is analyzed within a fractal framework. The data may be analyzed by a single- or a dual-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot. It is of interest to note that the binding rate coefficient and the fractal dimension both exhibit changes in the same direction for both the single-fractal and the dual-fractal analysis examples presented. For example, for a single-fractal analysis and for the hybridization of 10 nM 16CFl (oligonucleotide) to 16B immobilized via sulfosuccinimidyl-6-(biotinamido)hexanoate and streptavidin using chemical and thermal regeneration (Abel, A. P.; Weller, M. G.; Duveneck, G. L.; Ehrat, M. Widmer, H. M. Anal. Chem. 1996, 68, 2905-2912), an increase in the fractal dimension, Df from 1.211 (chemical regeneration) to 1.394 (thermal regeneration), leads to an increase in the binding rate coefficient, k, from 86.53 (chemical regeneration) to 100.0 (thermal regeneration). An increase in the degree of heterogeneity on the biosensor surface leads to an increase in the binding rate coefficient. When a dual-fractal analysis was utilized, an increase in the fractal dimension value from Df1 to Df2 leads to an increase in the binding rate coefficient value from k1 to k2. The fractional order of dependence of the binding rate coefficient, k1, on (a) the analyte (rRNA) concentration in solution and (b) on the fractal dimension, Df1, for the hybridization kinetics to detect Listeria species (Fliss, R.; St-Laurent, M.; Emond, E.; Simard, R. E.; Lemieux, R.; Ettriki, A.; Pandian, S. Appl. Microbiol. Biotechnol. 1995, 43, 717-724.) further reinforces the fractal nature of the system. The binding rate coefficient(s) expressions developed as a function of the analyte concentration in solution and the fractal dimension are of particular value since they provide a means to better control of biosensor or immunosensor performance.     

Effect of repetitive high-dose treatment with soluble complement receptor type 1 and cobra venom factor on discordant xenograft survival

Mice that are deficient in either the Pms2 or Msh2 DNA mismatch repair genes have microsatellite instability and a predisposition to tumours. Interestingly, Pms2-deficient males display sterility associated with abnormal chromosome pairing in meiosis. Here mice deficient in another mismatch repair gene, Mlh1, possess not only microsatellite instability but are also infertile (both males and females). Mlh1-deficient spermatocytes exhibit high levels of prematurely separated chromosomes and arrest in first division meiosis. We also show that Mlh1 appears to localize to sites of crossing over on meiotic chromosomes. Together these findings suggest that Mlh1 is involved in DNA mismatch repair and meiotic crossing over.     

Bacteriology of spirometer tubing and evaluation of methodology to prevent transmission of infection

Transmission of respiratory infection by a spirometer is a definite risk in countries like India where a majority of respiratory diseases are infective in nature. To assess this problem, scrapings and washing from a spirometer tube in regular use were taken for microbiological studies. Significant bacterial growth on culture included Aspergillus and acid fast bacilli. In order to check contamination, a segregation chamber was attached to the spirometer. Twenty-three patients used the spirometer with or without segregation chamber and a good correlation was shown between the two methods in forced expiratory volume in one second (r = 0.94), forced vital capacity (r = 0.92) and mid maximum expiratory flow rate (r = 0.90). It can be concluded that a spirometer may have significant growth of pathogenic bacteria and a segregation chamber may be used routinely with the spirometer in order to prevent its contamination.     

Studies on the mechanisms involved in antigen-evoked pleural inflammation in rats: contribution of IgE and complement

Immunoglobulin E (IgE) has been shown to play a critical role in the allergic late-phase reaction, which is marked by intense leukocyte infiltration and edema. In this study we assessed the allergic pleural inflammation triggered by intrapleural (i.pl.) challenge in sensitized rats. We examined pleural effluent from actively sensitized rats following anti-IgE monoclonal antibody (mAb) (MARE-1) provocation for protein exudation, neutrophil as well as eosinophil accumulation. Inflammatory changes triggered by antigen after passive sensitization with IgE mAb was also assessed for comparison. Total serum level of IgE was found to be about threefold increased 7-8 days post-active sensitization, remaining augmented for at least 30 days. Increased levels of peritoneal leukocyte-bound IgE and serum IgE with specificity to ovalbumin were also detected. Nevertheless, the anti-IgE challenge in 14-day actively sensitized was shown to be a weak stimulus of neutrophil and eosinophil accumulation, despite being able to cause intense protein extravasation. Similarly, antigen challenge of IgE-passively sensitized rats caused protein leakage that was comparable to that induced by anti-IgE mAb in actively sensitized rats but led to a much lower neutrophil/eosinophil infiltration. Also, blockade of complement with recombinant human soluble C receptor-1 (sCR1) treatment prevented actively sensitized rats from reacting to antigen with neutrophil and eosinophil recruitment without modifying protein extravasation. These data suggest that IgE and complement-mediated mechanisms probably account for the exudation and leukocyte infiltration that is characteristic of the pleural inflammatory response observed in actively sensitized rats.     

Formation, therapy and prevention of false aneurysm of the femoral artery following diagnostic and interventional heart catheterization

OBJECTIVE: As pseudoaneurysm of the femoral artery after catheter introduction is a frequent complication, its causes and therapeutic options were investigated in a large patient collective. PATIENTS AND METHODS: In a prospective study with colour-Doppler duplex sonography of 6928 patients after diagnostic and of 3764 after interventional cardiac catheterisation, pseudoaneurysms were diagnosed in 80 patients (0.75%), 46 after diagnostic (0.66%) and 34 after interventional (0.9%) catheterisation. RESULTS: The incidence was higher in women than men (1.33% vs 0.58%; P < 0.05). Anticoagulation after sheath removal was the leading risk factor (n = 55, 68.8%), especially after interventional coronary intervention 85.3 vs 56.5%, P < 0.05). Local compression under duplex sonography monitoring was undertaken in 69 patients (86.3%), achieving aneurysmal obliteration in 53 (76.8%). Spontaneous thrombosis occurred in 15 of the remaining 27 patients, and surgical closure became necessary in 12. CONCLUSIONS: These data indicate a risk profile for the occurrence of pseudoaneurysm after cardiac catheterisation which can be dealt with by preventive measures. Local compression under duplex sonographic monitoring was the treatment of choice with a high success rate and low incidence of complications.     

Sensitive patient-doctor communications relating to the breasts and prostate

The authors show case of lateral cervical cyst and carcinoma of the tonsil in woman 50 years, paying attention to large diagnostic and therapeutic difficulties. After operation of the lateral cervical cyst on the left side, metastasis of tumor followed, which was operated (after negative result of the thin-needle biopsy method) and histopathological examination of the tumor didn't prove atypical cells. In a few month after operation there followed tumorous infiltration in region angle of mandibula and in tonsillar region on the side and performed the thin-needle biopsy method showed planoepithelial carcinoma of the tonsil with transitional cells, which infiltrated the lingua, fundus of the oris and lymphonodes of the neck. Next the patient was sent to further treatment in the Oncological Hospital in Lodz. In connexion with advanced of the carcinoma, the using treatment (radiotherapy Co--60 and chemotherapy) was only the palliative treatment and prolongated life of the patient about 3 years.     

Domain structure analysis of elongation factor-3 from Saccharomyces cerevisiae by limited proteolysis and differential scanning calorimetry

Elongation-factor-3 (EF-3) is an essential factor of the fungal protein synthesis machinery. In this communication the structure of EF-3 from Saccharomyces cerevisiae is characterized by differential scanning calorimetry (DSC), ultracentrifugation, and limited tryptic digestion. DSC shows a major transition at a relatively low temperature of 39 degrees C, and a minor transition at 58 degrees C. Ultracentrifugation shows that EF-3 is a monomer; thus, these transitions could not reflect the unfolding or dissociation of a multimeric structure. EF-3 forms small aggregates, however, when incubated at room temperature for an extended period of time. Limited proteolysis of EF-3 with trypsin produced the first cleavage at the N-side of Gln775, generating a 90-kDa N-terminal fragment and a 33-kDa C-terminal fragment. The N-terminal fragment slowly undergoes further digestion generating two major bands, one at approximately 75 kDa and the other at approximately 55 kDa. The latter was unusually resistant to further tryptic digestion. The 33-kDa C-terminal fragment was highly sensitive to tryptic digestion. A 30-min tryptic digest showed that the N-terminal 60% of EF-3 was relatively inaccessible to trypsin, whereas the C-terminal 40% was readily digested. These results suggest a tight structure of the N-terminus, which may give rise to the 58 degrees C transition, and a loose structure of the C-terminus, giving rise to the 39 degrees C transition. Three potentially functional domains of the protein were relatively resistant to proteolysis: the supposed S5-homologous domain (Lys102-Ile368), the N-terminal ATP-binding cassette (Gly463-Lys622), and the aminoacyl-tRNA-synthase homologous domain (Glu820-Gly865). Both the basal and ribosome-stimulated ATPase activities were inactivated by trypsin, but the ribosome-stimulated activity was inactivated faster.