Modification of Electrical Pain Threshold by Voluntary Breathing-Controlled Electrical Stimulation (BreEStim) in Healthy Subjects

Background

Pain has a distinct sensory and affective (i.e., unpleasantness) component. BreEStim, during which electrical stimulation is delivered during voluntary breathing, has been shown to selectively reduce the affective component of post-amputation phantom pain. The objective was to examine whether BreEStim increases pain threshold such that subjects could have improved tolerance of sensation of painful stimuli.

Methods

Eleven pain-free healthy subjects (7 males, 4 females) participated in the study. All subjects received BreEStim (100 stimuli) and conventional electrical stimulation (EStim, 100 stimuli) to two acupuncture points (Neiguan and Weiguan) of the dominant hand in a random order. The two different treatments were provided at least three days apart. Painful, but tolerable electrical stimuli were delivered randomly during EStim, but were triggered by effortful inhalation during BreEStim. Measurements of tactile sensation threshold, electrical sensation and electrical pain thresholds, thermal (cold sensation, warm sensation, cold pain and heat pain) thresholds were recorded from the thenar eminence of both hands. These measurements were taken pre-intervention and 10−min post-intervention.

Results

There was no difference in the pre-intervention baseline measurement of all thresholds between BreEStim and EStim. The electrical pain threshold significantly increased after BreEStim (27.5±6.7% for the dominant hand and 28.5±10.8% for the non-dominant hand, respectively). The electrical pain threshold significantly decreased after EStim (9.1±2.8% for the dominant hand and 10.2±4.6% for the non–dominant hand, respectively) (F_{[1, 10]} = 30.992, p = .00024). There was no statistically significant change in other thresholds after BreEStim and EStim. The intensity of electrical stimuli was progressively increased, but no difference was found between BreEStim and EStim.

Conclusion

Voluntary breathing controlled electrical stimulation selectively increases electrical pain threshold, while conventional electrical stimulation selectively decreases electrical pain threshold. This may translate into improved pain control.     

Pain Threshold Analysis in Patients with Osteoarthrosis of Hip

The pain threshold was measured in patients with osteoarthrosis of the hip. The pain threshold was significantly lower in patients who required surgery than in controls. After successful surgery the threshold rose to normal levels. In patients with few or no symptoms from their osteoarthritic hips the pain threshold was high. Insensitivity to pain does not predispose towards osteoarthrosis of the hip. Indeed, the severity of symptoms can be directly related to an increased sensitivity to pain in osteoarthritic subjects.     

Effects of Sensory Behavioral Tasks on Pain Threshold and Cortical Excitability

Background/Objective

Transcutaneous electrical stimulation has been proven to modulate nervous system activity, leading to changes in pain perception, via the peripheral sensory system, in a bottom up approach. We tested whether different sensory behavioral tasks induce significant effects in pain processing and whether these changes correlate with cortical plasticity.

Methodology/Principal Findings

This randomized parallel designed experiment included forty healthy right-handed males. Three different somatosensory tasks, including learning tasks with and without visual feedback and simple somatosensory input, were tested on pressure pain threshold and motor cortex excitability using transcranial magnetic stimulation (TMS). Sensory tasks induced hand-specific pain modulation effects. They increased pain thresholds of the left hand (which was the target to the sensory tasks) and decreased them in the right hand. TMS showed that somatosensory input decreased cortical excitability, as indexed by reduced MEP amplitudes and increased SICI. Although somatosensory tasks similarly altered pain thresholds and cortical excitability, there was no significant correlation between these variables and only the visual feedback task showed significant somatosensory learning.

Conclusions/Significance

Lack of correlation between cortical excitability and pain thresholds and lack of differential effects across tasks, but significant changes in pain thresholds suggest that analgesic effects of somatosensory tasks are not primarily associated with motor cortical neural mechanisms, thus, suggesting that subcortical neural circuits and/or spinal cord are involved with the observed effects. Identifying the neural mechanisms of somatosensory stimulation on pain may open novel possibilities for combining different targeted therapies for pain control.     

塔叶苔属（Schiffneria Steph.）（Hepaticae）的研究

塔叶苔属（Schiffneria Steph.）建立于1894年。作者在研究中国标本时,发现一新种——Schiffneria yunnanensis C. Gao &; W. Li sp. nov.。塔叶苔属的配子体为叶状体,生殖枝具茎叶返祖现象,应置于叶苔亚纲的叶状体无组织分化类群——带叶苔目（Pallaviciniales）之中。     

Studies on the Genus Schizopepon Maxim. (Cucurbitaceae)

The classical and numerical taxonomy, palynology and the geographical distribution of the Genus Schizopepon are dealt with in the present paper. Having commented on various opinions regarding the systematic position of the genus, the present authors consider that C. Jeffrey’s treatment of Schizopepon as a new and monogeneric tribe, Schizopeponeae, should be supported. The gross morphological characters in the genus are assessed from the taxonomic point of view. Some characters, such as stamens with an elongated connective or not, different insertions of ovules and various forms of ovaries and fruits, may be used for distinguishing subgenera. The pollen grains of all the species were observed under light microscope (LM) and scanning electron microscope (SEM). The results show that a strong differentiation has taken place in the pollen of the genus, and in consequence it may be regarded as an important basis for dividing subgenera and species. Especially it should be pointed out that degrees of development of colpi and positions of ora are positively correlated with the external characters used for distinguishing subgenera. According to the morphological and palynological characters, the genus Schizopepon may be divided into three subgenera and eight species: 1. Subgenus Schizopepon: 5 species, S. bryoniaefolius Maxim., S. monoicus A. M. Lu et Z. Y. Zhang, S. dioicus Cogn., S. longipes Gagnep. and S. macranthus Hand.-Mazz.; 2. Subgenus Rhynchocarpos A. M. Lu et Z. Y. Zhang: 1 species, S. bomiensis A. M. Lu et Z. Y. Zhang; 3. Subgenus Neoschizopepon A. M. Lu et Z. Y. Zhang: 2 species, S. bicirrhosus (C. B. Clarke) C. Jeffrey and S. xizangensis A. M. Lu et Z. Y. Zhang. The 8 OTU’s including all the species of this genus and 31 characters, of which 16 are morphological characters and 15 palynological characters, were used in the numerical taxonomic treatment. After standardization of characters, the correlation and distance matrices were computed. The correlation matrices are made to test the various clustering methods. At last, the UPGMA clustering method was selected and its result is shown in the form of phenogram. The result of numerical analysis is similar to that of the classical classification. Schizopepon Maxim. is a genus of East Asia-Himalayan distribution. China has all 8 species and 2 varieties, of which 6 species are endemic. Based on the statistics of spedies number, the distribution centre of the genus is considered to be in the Hengduan Mountains (Yangtze-Mekong-Salwin water divides) and the adjacent areas of the southwest China.     

Studies on the characterization of the Rho(D) antigen.

The Rho(D) antigen of red cell membranes was solubilized using ethylene-diamine tetraacetic acid (EDTA) and 2-mercaptoethanol. The solubilized antigen was partially separated from other solubilized membrane components using molecular filtration. The antigen was treated with various enzymes to learn some of the chemical characteristics. It was found that the activity of the antigen, as measured by hemagglutination inhibition, was not affected by bee venom phospholipase A, Clostridium welchii phospholipase C, calf-intestinal alkaline phosphatase, Vibrio cholerae neuraminidase, pig kidney leucine aminopeptidase, bovine pancreatic carboxypeptidase A, and pig pancreatic carboxypeptidase B. However, the proteolytic enzymes, pronase, trypsin, chymotrypsin and papain, did destroy Rho(D) activity as measured by hemagglutination inhibition. These results indicate that protein is an important part of the active determinant of the Rho(D) antigen. The experiments by other investigators have shown that lipid is important to maintain the Rho(D) activity in the intact membrane; lipid probably helps to maintain the structural conformation of the Rho(D) molecule in its natural environment. The solubilized Rho(D) molecules are apparently not dependent on lipid for their Rho(D) activity.     

Systematic Studies in Czernaevia Turcz. (Umbelliferae)

Czernaevia Turcz. is a monotypic genus in the Umbelliferae, tribe Peucedaneae, with the only species Cz. laevigata Turcz. occurring in northern East Asia. Although the species has often been included in Angelica L., and sometimes even in Ostericum Hoffm., the present study indicates that it is distinct not only in having dimorphic petals, but also in its fruit structure, pollen morphology and phytochemical components. The fruit has numerous, compressed vittae, the pollen grains are not constricted at the equatorial region with a small P/E ratio (1.7-2.1), and neither coumarins nor flavonoids have been found to be present at significant level in the species. It is taxonomically probably rather isolated and the monotypic genus Czernaevia is tenable.     

Studies of rhesus monkey (Macaca mulatta) hemoglobin.

One hemaglobin was found in the adult rhesus monkey (Macaca mulatta) by the technique of isoelectric focusing. In addition to the adult hemoglobin, one fetal hemaglobin was observed in neonates of the same species. The alpha and non-alpha globins of rhesus monkey hemoglobins showed similar electrophoretic mobilities as those of human hemoglobin A by cellulose acetate membrane electrophoresis. It appeared that the rhesus monkey hemoglobin system is a good model system for the study of human hemoglobin development.     

Studies on the Resin Glands of Azadirachta indica A. Juss. (Meliaceae)

The leafy shoots of Azadirachta indica have numerous, yellowresin glands, composed of a short stalk and sub-glandular tissuebeneath an epithelium-like 1-2-layered secretory tissue. Thefoot arises from the epidermis. The resin glands are derivedfrom a single papillate epidermal cell which functions as aresin gland initial. Histochemical localization using fluorescencemicroscopy confirmed the resinous nature of the secretion. Thegeneral structure of the glands shows similarity to extra-floralnectaries. Reports in the literature on the occurrence of extrafloralnectaries in Meliaceae should be confirmed by analysis of thesecretions if they are to be accepted. Azadirachta indica, resin glands, ontogeny, structure, secretion     

Taraxacum (Spectabilia) nordstedtii Dahlst. in Central Europe (Studies inTaraxacum)

The present study provides a survey of the variability, distribution, ecology and other features ofTaraxacum (sect.Spectabilia) nordstedtii Dahlst. in central Europe. Chromosome counts (hexaploid chromosome number?2n=48?has been confirmed) of the species are also given. A lectotype has been chosen of the syntypes. It is pointed out thatT. nordstedtii is likely to occur in Austria, Bavaria and Poland.