Electromyography interference pattern decomposition

Decomposition of an interference pattern enables examination of individual electromyography (EMG) motor units and their firing rates at more than minimal contraction forces. In this decomposition method, significant events with a constant occurrence (near motor unit action potentials) can be enhanced, and unwanted events (distant motor unit action potentials, artifacts) eliminated, by calculating the average accumulated change while sliding a fixed-width window along the digitized EMG interference pattern. Nonparametric statistical methods are then applied to these data to determine which information is significant at the .05 level. The exact duration of significant information is identified without the need for arbitrary thresholds and filters to eliminate unwanted information. Events are then classified into groups of similar events by comparing: (1) correlation coefficients, (2) point-to-point differences, (3) amplitudes, and (4) areas. The classification is further refined by the use of firing-rate information.

[Studies on chemical protectors against radiation. XXXIV. Survival effects of aqueous extracts of various Chinese traditional medicines on radiation injury]

In order to develop a nontoxic radioprotector, 60 kinds of Chinese traditional medicines were chosen, and their aqueous extracts tested for their survival effects against the lethal effect of X-irradiation in mice. Radiation factors used were as follows: soft X-rays, 2100R (5.418 x 10(-1) Ckg-1), 70 kVp, 10 mA, 10 mm acrylic filter, 70R (1.806 x 10(-2) Ckg-1)/min. Among 60 medicines tested by intraperitoneal injection immediately before the irradiation, 15 are shown to have the significant survival effect. These 15 effective medicines were also tested by intraperitoneal injection after the irradiation, and the survival effect was recognized in Keisi-syakuyaku-chimo-to, Keigai-rengyo-to, Simotu-to, Syakuyaku-kanzo-to and Hange-syasin-to. On the other hand, the survival effects of 25 medicines including the above-mentioned 15 medicines were investigated by the oral administration at various times before or after the irradiation. As the result of these studies, only Keigai-rengyo-to and Bukuryo-in are shown to have the significant survival effect when administered 2 h before the irradiation.

[Studies on chemical protectors against radiation. XXXIII. Protective mechanisms of various compounds against skin injury induced by radiation]

The radiation protective mechanisms on skin injury induced by soft X-irradiation were investigated by use of various radiation protective agents such as sulfur compounds (MEA, MEG, thiourea), nucleic acid constitutional compounds (adenosine, inosine), antioxidative compounds (sesamol, ferulic acid, ascorbic acid), crude drugs (Rosae Fructus, Anemarrhenae Rhizoma, Trapae Fructus, Forsythiae Fructus, Aloe arborescens). Scavenge action of activated oxygen, inhibitory effect of lipid peroxidation, induction of antioxidative protein and protective effect against damage of deoxyribonucleic acid and superoxide dismutase by X-irradiation were evaluated as the radiation protective mechanisms, and relationship between these results and protective effect of skin injury induced by radiation was studied.

[Studies on chemical protectors against radiation. XXXII. Protective effects of methanol extracts of various Taiwan crude drugs on radiation injuries]

This study is to investigate radioprotective effects of 23 Taiwan crude drugs on X-ray induced bone marrow death and skin injury in mice. Each methanol extract of these Taiwan crude drugs was injected intraperitoneally into ICR male mice at 6 weeks of age before irradiation. Mice were whole-body irradiated with a soft X-ray generator. Radiation factors of the two screening tests used were as follows: 70 kVp, 10 mA, 10 mm acrylate filter, 70R/min, 2100R for survival test, and 30 kVp, 10 mA, 190R/min, 1100R for protective test on skin injury. As a result of these studies, the survival effect was recognized in Solani Incani Herba and Orthosiphi Aristati Herba. On the other hand, Mimosae Herba, Canarii Radix, Bombacis Radix, Arecae Fructus, Hedyotidis Diffusae Herba and Cynomorii Caulis were shown to have significant protective potency on skin injury.

[Studies on chemical protectors against radiation. XXIX. Protective effects of methanol extracts of various Chinese traditional medicines on skin injury induced by X-irradiation]

In order to investigate useful protective medicines for the relief of skin injury induced by irradiation, 60 methanol extracts of Chinese traditional medicines were used in the test of protective potency on skin injury. ICR male mice at 6 weeks of age were whole-body irradiated with 1100R by using a soft X-ray generator (30 kVp, 10 mA, 190 R/min). Each methanol extract of these medicines was injected intraperitoneally into mice before or after irradiation. The degrees of skin injury were determined by a score system of skin reaction within the observation period from 21st to 40th day after irradiation. Protective potency of each medicine on skin injury was calculated from the maximum mean scores of administrated group and un-administrated group. As a result of these studies, the protective potency was detected in Unsei-in, Kumibinro-to, Keisi-syakuyaku-chimo-to, Keigai-rengyo-to, Gosyuyu-to, Koso-san, Saiko-seikan-to, Syo-kankyo-to, Syo-saiko-to, Syoma-kakkon-to, Sen-kan-meimoku-to, Zokumei-to, Sokei-kakketu-to, Bokuryo-in, Mao-to and Rikkunsi-to by intraperitoneal injection before irradiation. Of these effective medicines, only Unsei-in and Mao-to are shown to have a significant protective effect by intraperitoneal injection after irradiation.

[Studies on chemical protectors against radiation. XXVII. Survival effects of methanol extracts of various Chinese traditional medicines on radiation injury]

The survival effect of mice irradiated with a lethal dose of X-ray was studied by use of 60 kinds of Chinese traditional medicines. Methanol extracts of these medicines were prepared, and then each extract injected intraperitoneally into male mice before or after whole-body irradiation. As a result of these studies, the survival effects with Ogi-kentyu-to, Simotu-to, Sessyo-in, Zokumei-to and Boi-ogi-to were observed by intraperitoneal injection before irradiation. Of these effective methanol extracts, only Zokumei-to was shown to have a significant survival effect by intraperitoneal injection after irradiation.

Pro-convulsant actions of theophylline and caffeine in the hippocampus: implications for the management of temporal lobe epilepsy

The pro-convulsant actions of theophylline and caffeine have been investigated using the hippocampal slice preparation and rats administered kainic acid or Metrazol. Both theophylline and caffeine induced the generation of epileptiform activity in the CA3 region of the hippocampal slice with convulsive dose50 (CD50) values of 3 microM respectively. Kainic acid-induced bursting in hippocampal slices was enhanced by theophylline (0.3-30 microM) and caffeine (1-100 microM). Theophylline induced burst firing in response to electrical stimulation in hippocampal area CA3 but not area CA1. Theophylline (50 mg/kg) strongly potentiated the effect of the limbic convulsant kainic acid in vivo whilst a dose of 200 mg/kg was necessary to significantly lower the threshold dose of Metrazol required to induce generalized convulsions. We conclude that alkylxanthines, probably by antagonizing the effect of endogenous adenosine, exert a pro-convulsant action in the hippocampus which preferentially promotes limbic seizures.

L-proline depolarizes rat spinal motoneurones by an excitatory amino acid antagonist-sensitive mechanism

1 Isolated spinal cords prepared from neonatal rats were used to examine the effects of L-proline (L-Pro). 2 L-Pro (1-8 mM) depolarized ventral and dorsal roots in a dose-dependent manner with one sixth of the potency of L-glutamate (L-Glu). L-Pro was four times more potent than D-Pro. Prolonged application of L-Pro produced a plateau depolarization of motoneurones with no apparent fade. 3 Omission of calcium ions from the medium potentiated the depolarizing actions of L-Pro, L-Glu and quisqualate. 4 L-Pro was antagonized by concentrations of 2-amino-5-phosphonovalerate (25 microM), gamma-D-glutamylglycine (100 microM) and Mg2+ ions (1 mM) that depressed responses to N-methyl-D-aspartate (NMDA). The NMDA receptor-mediated component of the response to L-Pro was estimated to be 60-70%. 5 These data suggest that L-Pro should be considered as a possible excitatory neurotransmitter and that, because L-Pro is a neutral compound, excitatory amino receptors may not require an agonist to possess two anionic groups and one cationic group.

Baclofen suppresses bursting activity induced in hippocampal slices by differing convulsant treatments

Epileptiform activity was induced in area CA3 of hippocampal slices by superfusion of medium containing 50 microM bicuculline and 3.5 mM K, 50 microM bicuculline and 5 mM K, 50 nM kainic acid and 3.5 mM K, or 7 mM K. Burst potentials were recorded at rates between 5 and 44/min, depending on the convulsant treatment. Baclofen reduced the frequency of burst firing in all slices tested in a dose-dependent manner, with little change in the morphology of individual bursts. Thus baclofen primarily affected the initiation of epileptiform discharges. IC50 values varied between 27 and 500 nM and were positively correlated with the rate of bursting. These experiments indicate that baclofen, at concentrations present in the CSF of patients treated for spasticity, has an anticonvulsant-like effect in the hippocampal formation and suggest that its mode of action is to reduce the excitability of pyramidal cells.

Adenosine inhibits epileptiform activity arising in hippocampal area CA3

The ability of adenosine and structurally-related compounds to inhibit epileptiform activity induced by bicuculline in the CA3 region of the hippocampal slice of the rat was examined. Bath application of all purinoceptor agonists tested reduced the frequency of generation of burst potentials. Analysis of dose-response curves yielded the following IC50 values: adenosine, 1.5 microM; 2-chloroadenosine, 0.144 microM; 5'-(N-ethyl)carboxamidoadenosine, 30.2 nM; L-phenylisopropyladenosine, 12.1 nM; cyclohexyladenosine, 7.9 nM. Theophylline (30 microM) increased the rate of bursting and antagonized the effect of exogenous adenosine. Dipyridamole (0.03-1 microM) reduced the occurrence of burst firing. In slices untreated with bicuculline, theophylline (30 microM) and adenosine deaminase (10 micrograms ml-1) induced bursting activity. These results demonstrate that purinoceptor agonists can suppress epileptiform activity in the hippocampus and suggest that adenosine may act as an endogenous anticonvulsant.

[Clinical observation and preliminary study of termination of early pregnancy by administration of yellow daphne]

74 cases of early pregnancy with periods of amenorrhea of 36-69 days from the last menses were terminated by using a single dose intrauterine instillation of Wikstro-Emia Chamaedaphne Meisn Alcohol Solution (WCMAS). According to the dosages used, they were divided into 3 groups: 0.2gm, 0.4gm, and 0.6gm of WCMAS. The efficacy of the different dosages was evaluated. The most successful in the termination of early pregnancy (less than 56 days) was the 0.4gm group, the effective rate being 96.6%, and the complete abortion rate being 93.3%. The average duration of complete abortion in all was 21.3 hours, and the averge duration of vaginal bleeding was 10.9 days. Although amount of bleeding was regarded as a little greater than that of normal menstruation by some patients, yet there were no serious side effects occurring, except that some patients experienced some subjective lower abdominal pain and vomiting. Serum hCG and progesterone were determined by radioimmunoassay technique in 31 cases, and it was found that the hCG and progesterone levels both declined rapidly at 12 hours and fell to 35.5% and 46.4% respectively 24 hours after injection. Under microscopic examinations necrotic degeneration was observed in most of the chorionic villi, and marked necrosis and hemorrhage in the decidua. The granulocytes in the decidua also decreased in amount. 48 cases were followed up recently; no side effects were found and there was no interference with re-pregnancy.

Electrophysiological effects of antidepressants on mammalian hearts and crayfish giant axon

Cardiotoxicity is known to occur in patients with or without preexisting cardiac diseases during treatments with the tricyclic antidepressants, amitriptyline and imipramine. The antiarrhythmic action of tricyclics was also demonstrated in clinical studies and in animal experiments. Bupropion, a novel antidepressant, is being studied in man and to date has been found to be effective and devoid of cardiovascular toxicity. This study was intended to show the direct effect of tricyclic antidepressants on excitable membrane and to compare their potential toxicity with bupropion in isolated tissues. In crayfish giant axon, all antidepressants exhibited local anesthetic-like action by reducing the action potential amplitude and maximal rate of upstroke (dv/dt). The tricyclics slowed spontaneous sinus discharges in rat atrium and prolonged the duration of evoked action potential in guinea pig atrium with a concomitant decrease in dv/dt. A quinidine-like action of the tricyclic agents is displayed in the termination of spontaneous depolarization and the suppression of dv/dt of evoked action potential in canine Purkinje fibers. The membrane depressant action of antidepressants resulted in the reduction of dv/dt and increased membrane refractoriness in both atrial and ventricular tissues; excitation is blocked even when resting membrane potential remained fully polarized. The present results confirmed the direct quinidine-like action on cardic tissues, which is probably related to the antiarrhythmic and/or cardiotoxic manifestation in man and animals. On on excitable tissues studied, tricyclic antidepressants are the most potent in blocking membrane excitation, while bupropion is the least toxic on the molar basis.