Intersession Interval and Reductions in Frontalis EMG During Biofeedback Training

Subjects were given practice in reducing frontalis EMG using biofeedback procedures with either Short, Medium, or Long intervals between practice sessions. After 10 sessions there were significant differences among the groups in decreasing EMG amplitude.     

The significance of the interrelationship between the intensity of the contractile state and the velocity of relaxation in adapting cardiac muscle to function at high work loads.

The relationship between the amplitude of contraction and the velocity of relaxation has been studied, using papillary muscles isolated from rats and from guinea-pigs. Under isotonic conditions and with varying preloads an increase in the amplitude of contraction is followed by a proportionate increase in the velocity of relaxation. This same relationship was observed in experiments performed under isotonic conditions with different afterloads, provided that the contractile force did not exceed 60% of the maximal isometric value. This correlation disappeared at high work loads under isometric conditions, when the resting length exceeded a critical value. A positive correlation between developed ventricular pressures and the velocity of relaxation was also found in anaesthetized dogs and rats, when the developed pressure increased in response to an increased resistance in the outflow tract.When the frequency at which isolated guinea-pig papillary muscles was stimulated to contract was increased, the velocity of relaxation increased, the increase being proportional to the product of the amplitude and frequency of contraction. This relationship may reflect the existence of an autoregulatory mechanism that preserves the diastolic pause. The cellular basis of this autoregulatory mechanism is probably associated with the overloading of the heart with Ca²⁺; it is impaired by conditions which result in hypertrophy, hypothermia or a raised myoplasmic Ca²⁺.     

肺癌的MRI定量研究

目的：评价信号强度及驰豫时间测量对肺癌的诊断价值。材料和方法：测量了９５例肺癌之癌实体、转移淋巴结及肿瘤继发改变的驰豫时间及信号强度，并将各值用脂肪及肌肉相关值标准化，以评价各变量对肺癌的诊断价值。结果：Ｔ１ＷＩ及Ｔ２ＷＩ第一回波上的信号强度在脂肪或肌肉标准化前后对各种病变均无鉴别意义：Ｔ２ＷＩ后三个回波信号强度及组织驰豫时间在标准化前后均有一定鉴别作用，能够区分的组织主要是胸水、肿瘤坏死及纤维化。对于各种不同组织类型的癌实体之间，癌实体与转移淋巴结之间，癌实体与其继发改变之间几乎每个变量都无法鉴别。但通过信号变化曲线尤其是长回波图像上的信号特点，可以使各病变的差别更直观的表现出来，提高鉴别诊断的可能性。结论：信号强度及驰豫时间的测量虽然可以区分肺癌及部分继发病变，但测量耗时费力且不能提供比肉眼观察更多的诊断信息，临床工作中不宜常规采用，应用价值有限。     

A novel non-adrenergic,non-cholinergic nerve-mediated relaxation of the pig bladder neck: An examination of possible neurotransmitter candidates

Electrical field stimulation of the isolated pig bladder neck preparation initiated rapid non-adrenergic, non-cholinergic nerve-mediated relaxations. A wide range of substances were examined as possible candidates for the neurotransmitter involved. Of these, only 5-hydroxytryptamine, vasoactive intestinal polypeptide, adenosine and adenosine 5′-triphosphate produced relaxations. Noradrenaline, acetylcholine, substance P, bradykinin and angiotensin II caused contraction, while neurotensin, somatostatin, bombesin and γ-amino butyric acid were without effect. The nerve response was not blocked by methysergide, ketanserin, chymotrypsin, apamin or 8-phenyltheophylline, although methysergide antagonised the responses to 5-hydroxytryptamine, chymotrypsin blocked the responses to VIP, and 8-phenyltheophylline antagonised the responses to adenosine and ATP.     

Magnetic resonance imaging of the brain in Wilson's disease

Summary Fifteen patients with Wilson's disease were examined, using spin-echo (SE) and gradient-echo (GE) sequences with 0.5 T and 1.5 T magnetic resonance (MR) imagers. They fell into three groups: groups 1 and 2 were examined retrospectively after 3–18 years of treatment, while group 3 was examined prospectively from the start of treatment, after recommencement of treatment, or inadequate treatment. MRI was sensitive to changes in the basal ganglia at sites typical of Wilson's disease and was useful for documenting the effects of treatment. It was found necessary to estimate the relaxation times T1 and T2, to better assess improvement or transient worsening of the disease in the prospective group. Residual cavitation and gliosis could be distinguished in the retrospective group using a subtraction technique.     

Relaxation transfer in electrodermal activity as affected by a new minor tranquillizer (4306CB)

Four groups (n=6) were taken through two sessions of aversive instructed conditioning. Shocks (UCS) were administered by the subjects themselves each time the second-hand of a clock facing the S passed 6 and 12. The second-hand (CS) became visible 10 sec before the points of shock-administration. 45 min before the first session groups I and III received a placebo capsule, groups II and IV a 4306CB capsule. At the second session, group I was shifted to 4306CB and group II to placebo, while the other two groups received the same treatment as on session 1. Electrodermal reactivity was assessed in Log micro Mho units through phasic skin resistance response magnitudes (OR/CR, AR, UCR). In comparing the reactivity between the drug and placebo conditions of the first session, greater reactivity was found in the AR and UCR for the drug group. The shifted groups tended to increase their reactivity from session 1 to 2, while the non-shifted groups showed a corresponding tendency towards reduction of reactivity. This result suggests that the shift in treatment induces dissociative interference with relaxation transfer between sessions.This research was supported by a grant from the Social Science Research Council of Sweden.     

Studies on the distensibility characteristics of capacitance and resistance vessels of the isolated rabbit ear

Summary Using a plethysmographic technique, the distensibility characteristics of capacitance and resistance vessels at varying vasal tone were determined simultaneously in the rabbit's ear, which represents a uniform vascular bed of skin vessels. The pressure-volume curves of the capacitance vessels showed hysteresis loops. The hysteresis became greater at increasing venous tone. Stress-relaxation occurred with repeated congestion and could be demonstrated by the pressure-volume curves. At high venous tone stress-relaxation could be shown also by a decrease of the venous pressure-gradient indicating an increase of the venous cross section area. The distensibility characteristics of the resistance vessels resembled those of the capacitance vessels showing the same dependency on vasal tone. However, stress-relaxation could not be demonstrated in these vessels.This investigation was supported by Contract F 61052-68-C-0069 of the USAF School of Aerospace Medicine, European Office of Aerospace Research (OAR), U.S. Air Force.     

On the mechanism of histamine action in cardiac muscle.

The effect of histamine on electrical and mechanical properties of guinea-pig ventricular muscle fibers was investigated. It was found that the drug decreased in rate of tension development, the rate of fall of the twitch and decreased the time to peak tension. The height of the plateau of the action potential was increased by histamine and this seems to explain, at least, part of the drug action on heart contractility. The uptake and efflux of 45Ca were both increased by the drug. The positive inotropic action of histamine is largely dependent on the external calcium concentration and temperature and is abolished in low Na solution. It was found that histamine has a marked relaxing action which is probably related to increased Ca sequestration by the sarcotubular system. The drug also produced a decrease in post-extrasystolic potentiation.     

Inhibition of cyclic-3′,5′-nucleotide-phosphodiesterase as a possible mode of action of papaverine and similarly acting drugs

Naunyn-Schmiedeberg's Archives of Pharmacology -     

Further observations on species-determined differences in the calcium-accumulating activity of cardiac microsomal fractions.

The possible existence of a species-determined difference in the ability of cardiac microsomes to accumulate and release Ca²⁺ has been further investigated, by using a dual beam spectrophotometric method to detect rapid changes in Ca²⁺ flux. Guinea pig, rat and rabbit microsomal fractions were used. When incubated in an oxalate-free reaction mixture the rat, rabbit and guinea pig fractions accumulated approximately the same amount of Ca²⁺ but the rat microsomes accumulated this Ca²⁺ at a faster (P < 0.001) rate than did either of the other two species. Ca²⁺ was released sooner (P < 0.001) at a faster rate (P < 0.001) from the rat microsomes than from either of the other two species. If an oxalate-containing incubation medium was used the rat microsomes accumulated Ca²⁺ at a faster (P < 0.001) rate than did either of the other two species. Even when oxalate was present Ca²⁺ was rapidly released from the rat (13.65 ± 1.40 n mol Ca²⁺/mg protein/min) microsomes, reflecting the relative inability of these microsomes to retain Ca²⁺.These results are discussed in terms of the hypothesis that some of the peculiar contractile behaviour which is exhibited by rat heart muscle may reflect a peculiarity in the ability of its sarcoplasmic reticulum to accumulate and release Ca²⁺, rather than to the presence of a relatively active Ca²⁺-stimulated myofibrillar ATPase enzyme.