Electromyographic study on the sternocleidomastoid and pectoralis major muscles during respiratory activity in humans

Introduction: This study aimed to evaluate the simultaneous and maximum activities ofthe sternocleidomastoid (SCM) and pectoralis major (PM) muscles, to determine how the two types of breathing patterns (normal and forced) can affect these activities , and to verify which of these muscles could be used to establish an evaluation protocol for patients undergoing mechanical ventilation. Methods: Eleven healthy men, aged 18 to 25 years, participated in this study. The individuals remained in supine position using a respiratory belt to monitor both inspiratory and expiratory phase during shifts in the rib cage, performing three repetitions for the normal and forced respiratory movements, while keeping the breathing rhythm with a standard metronome. Electromyographic signals were captured using bipolar surface electrodes placed on the lower third of the SCM muscle and on the lower PM muscle fibers. Electromyographic signals were analyzed and the root mean square (RMS) values were calculated for a complete respiratory cycle. The EMG values were analyzed using the Bonferroni test for multiple comparisons. The homogeneity of variances was verified using the logarithmic transformation (LOG). The level of statistical significance was set at 5% (SPSS 19.0). Results: The values showed that there are signiicant differences between the EMG values of the SCM muscle during normal and forced respiration and the EMG values of the ECM and PM muscles during forced respiration. Conclusion: These results showed that the SCM muscle can be an indicator for the development of parameters to be used in the analysis of patients with respiratory failure.

Nerve innervation of the hand and associated nerve dominance aggregates in the somatosensory cortex of a primate (squirrel monkey)

The cutaneous innervation territories of the median, ulnar, and radial nerves to the hand were determined from neurophysiological recordings of peripheral mechanoreceptor axons in adult squirrel monkeys. These territories were then related to cutaneous receptive fields of cortical area 3b neurons to determine how low-threshold inputs from each hand nerve map onto the primary somatosensory cortex. The results indicate that mechanoreceptor axons in each nerve innervate a continuous skin territory covering about 40% of the hand surface. The total territory of each nerve contains subregions of skin that are either autonomously innervated by that nerve or that receive overlapping innervation from more than one nerve. The autonomous, overlap, and total territories of each nerve are relatively constant from hand to hand. In the area 3b cortex, low-threshold afferents from each nerve provide inputs to aggregates of cortical neurons. The cortical aggregates relating to the median and ulnar nerves are arranged as continuous, rostrocaudally oriented bands, whereas aggregates relating to the radial nerve are discontinuous and more patch-like. Similar patterns of bands and patches, and similar compression ratios of skin/cortical area, are seen across different monkeys. These findings demonstrate that the primary somatosensory cortex of normal adult primates contains bands or patches of neurons that are dominantly activated by low-threshold inputs from specific hand nerves. This approach of delineating nerve territories and their related cortical dominance aggregates provides a useful means of analyzing cortical images of nerves and of quantitating peripheral and central patterns of deprivation after nerve injury.

The grid-blot: a procedure for screening large numbers of monoclonal antibodies for specificity to native and denatured proteins

This report describes a procedure referred to as a grid-blot for simultaneously testing up to 30 monoclonal antibodies for specificity with an equivalent number of different proteins on a single sheet of nitrocellulose paper. Only 150 microliters of hybridoma culture supernatant is required for the screening and the entire procedure can be completed in less than five hours. This assay was developed to quickly identify those hybridoma cultures producing antibodies that preferentially recognize the native form of a protein and those that also recognize the SDS denatured form and were optimal for use in Western blots. Monoclonal antibodies raised against two distinct proteins, myofibril C-protein (120 antibodies) and the catalytic subunit of cyclic-AMP dependent protein kinase (240 antibodies) were tested. The grid-blot results indicated that 85 of the C-protein antibodies and 55 of the catalytic subunit antibodies were monospecific. Only 4 of the C-protein and 9 catalytic subunit antibodies showed a preferential staining for the appropriate native protein. The antibodies that stained the denatured protein most intensely in the grid-blot corresponded with those that produced the best immunostain in the Western blot. Finally, a version of the grid-blot was found to be an efficient means of determining antibody isotypes.

The influence of stimulated peritoneal feeder cells and mitogens upon antibody secreting hybridomas

Peritoneal exudate cells from mice injected with immunostimulatory agents were evaluated for their ability to promote hybridoma growth. Peritoneal cells from mice receiving peritoneal injections of either Freund's incomplete adjuvant or pristane, seven days prior to harvesting, produced the greatest number of antibody-producing hybridomas. Freund's incomplete adjuvant produced 16 fold more peritoneal cells than unstimulated mice, thus reducing the number of mice needed to supply feeder cells for the hybridoma cultures. In separate experiments a number of B-lymphocyte stimulating lectins and factors were tested for their ability to promote hybridoma growth. 2-mercaptoethanol (25 microM) routinely increased the number of antibody producing hybridomas by 5 to 15 fold. 2-mercaptoethanol had a varying ability to increase the numbers of hybridoma colonies. The cloning efficiency, rate of cell growth and antibody production of hybridoma cell lines, previously produced in the absence of 2-mercaptoethanol could also be increased when this reducing agent was added to the culture medium.