Interaction of amphiphilic chlorin-based photosensitizers with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine monolayers

The drawbacks of the presently used photosensitizers include their relatively low selectivity toward cancer cells, and long-lasting accumulation in healthy tissues. Our recent results indicate that conjugating a photosensitizer with folic acid both enhances the active uptake by cells, and decreases the accumulation in healthy tissue. Here, the interaction between 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers used as model membranes, and three different photosensitizers were studied; the derivatives were the non-conjugated meta-tetrahydroxyphenylchlorin (m-THPC, CHL1) and tris(3-hydroxyphenyl)-4-carboxyphenylchlorin (CHL2), as well as a folic acid-conjugated m-THPC-like molecule (CHL3). The results obtained indicate that the folate moiety present in the conjugated derivative CHL3 is involved in the interaction with the phospholipid polar heads. This interaction may be responsible for a better miscibility of CHL3 with the DPPC films compared to CHL1 and CHL2, while elimination of CHL3 from the tissue may be due rather to specific, biological processes and not to its polarity.     

Rhythmic arm swing enhances long latency facilitatory effect of transcranial magnetic stimulation on soleus motoneuron pool excitability

The purpose of this study was to investigate whether rhythmic arm swing modulates the long latency effect of transcranial magnetic stimulation (TMS) on soleus motoneuron pool excitability. Ten healthy humans rhythmically swung the left arm back and forth in a sitting position. The soleus H-reflex was evoked when the arm was in the backward swing phase. Conditioning TMS was delivered over the motor cortex 8?ms before the soleus H-reflex was evoked. The soleus H-reflex amplitude in both legs was depressed by the rhythmic arm swing. In contrast, rhythmic arm swing enhanced the facilitatory effect of conditioning TMS over the motor cortex contralateral to the arm swing side on the soleus H-reflex ipsilateral to the arm swing side. This finding indicates that rhythmic arm swing enhances some polysynaptic facilitatory pathways from the motor cortex contralateral to the arm swing side to the soleus motoneuron pool ipsilateral to the arm swing side.     

Physical contact while handling is not necessary to reduce fearfulness in the rabbit

Rabbits handled around nursing time during the first week after birth show reduced fear response toward humans. Our earlier attempt to reduce the duration of daily treatment necessary to achieve this effect showed that even a minimal human contact, characteristic of animal caretaking in intensive rabbitries, results in reduced fearfulness. Being descendants of a nocturnal mammal species, olfactory cues are of central importance in rabbits, especially just after parturition, when the other sensory organs are undeveloped. In the present experiment, we investigated whether exposing newborn rabbit pups to human smell at nursing time is sufficient to reduce fear of humans in rabbits. For this, we exposed rabbit pups to one of the following handling treatments in the first week of life: (1) full handling, within 0.5 h after nursing, which consisted of removing the pups from the nest and weighing them (about 5 min/litter), (2) exposing rabbit pups to the smell of humans for about 5 min/litter, without touching them, (3) untreated controls. At 28 days of age, the timidity of the pups was measured in a 5 min approach test. Pups that were either handled or exposed to human smell appeared to be equally less fearful as they approached the experimenter's hand with a lower latency and more frequently than untreated controls. This indicates that olfactory exposure during handling results in imprinting even without a human contact in rabbits.     

Isolation and Structure of Protodestruxin from Metarrhizium anisopliae

µ-Calpain quickly split the α-connectin in myofibrils into β-connectin, and then produced a 1700-kDa component. Cathepsin D also split α-connectin into β-connectin, further degrading it to fragments smaller than the 1700-kDa component with increasing incubation time. The action of cathepsin D on the connectin molecule was distinctly different from that of, µ-calpain in terms of the splitting rate and manner. When freshly excised muscle was exposed to a temperature of 37°C, complete disappearance of connectin (α, β and 1700-kDa component) was observed within 36h. In contrast, at 2°C, about 75% of connectin was retained as β-form even after 3 weeks. The present data suggest that the degradation of connectin in muscle might be caused by, µ-calpain in the early stage of aging, and then with time, this action is replaced by m-calpain or cathepsin D. However, the possibility of other intrinsic proteases participating in the degradation of connectin still remains.     

Bismuth-inhibitory effects on bacteria and stimulation of fungal growth in vitro

Bismuth salicylate was found to inhibit the growth of a range of bacteria and yeast, “Candida albicans”. In general the growth of bacteria did not result in increase in bismuth solubilisation, in contrast, bismuth solubilisation increased following the growth of C. albicans. A significant increase in the biomass (dry weight) of Aspergillus niger and Aspergillus oryzae occurred in vitro when these fungi were grown in the presence of bismuth salicylate. Biomass increase occurred over a range of bismuth compound additions, which in the case of A. oryzae was associated with increase in the solubilisation of the insoluble bismuth compounds.     

A new method for temperature compensation of electrical conductivity using temperature-fold dependency of fresh water

A new method for temperature compensation of electrical conductivity (EC) is proposed. A relationship between temperature and EC was investigated in detail by a simple experiment using natural and artificial fresh water. Results showed that the temperature dependency of EC varied from 0.03 to 0.02, with temperature increasing from 3°C to 35°C. This means that a traditional method for compensating for EC using a constant coefficient is invalid, so that a temperature-fold dependency must be taken into consideration to standardize EC to a common temperature.     

经皮穴位电刺激辅助全身麻醉减少镇痛药及其副作用的随机对照研究

目的:1.为了明确经皮穴位电刺激是否可以减少择期乳腺癌根治术麻醉药的用量,产生针刺镇痛效应,并且缩短患者苏醒和拔管时间;2.经皮穴位电刺激是否可以明显的减少术后恶心呕吐、眩晕及皮肤瘙痒等麻醉相关并发症的发生;3.探讨电针镇痛效应是否与患者体内β-内啡肽、游离皮质醇有关。方法:选择60例进行择期乳腺癌根治术的患者,随机分为对照组(CON组)、经皮穴位电刺激组(TEAS组),每组30人。入手术室后TEAS组选择双侧合谷穴(LI4),内关穴(PC6)和足三里(ST36)作为穴位刺激30分钟,刺激频率为疏密波2/30 Hz,强度以患者所能承受为限(6-8 m A),对照组患者则仅将电极贴片贴于穴位,不给予电刺激。术中行Narcotrend脑电监测仪监测麻醉深度,记录术中血流动力学参数,采集外周静脉血行皮质醇和β-内啡肽检测。首要观察指标是术中瑞芬太尼用量,次要观察指标是麻醉苏醒质量和麻醉相关副作用。结果:TEAS组瑞芬太尼用量(0.063±0.026μg·kg-1·min-1)相比对照组(0.091±0.032μg·kg-1·min-1)减少了30%。两组间术中血流动力学和血浆β-内啡肽、皮质醇水平无显著差异(P0.05)。然而,拔管和苏醒时间在对照组分别为17(5)和14(8)min显著长于TEAS组(P0.05),TEAS组术后24小时眩晕和皮肤瘙痒发生率显著低于对照组(P0.05)。结论:经皮穴位电刺激确实产生了针刺镇痛效应,大大减少了全麻术中瑞芬太尼用量并降低术后麻醉相关并发症的发生率,是一种值得推广的辅助麻醉方法。     

Cortical Influences on Neurons of the Lateral Reticular Nucleus Responding to Noxious Stimuli

The effect of frontoparietal sensorimotor (FPSM) cortex stimulation on both the spontaneous and the noxious evoked activity of neurons in the lateral reticular nucleus (LRN) was tested in barbiturate-anesthetized rats. Ninety-three LRN neurons that responded to a noxious heat stimulus (HS) were recorded (72% antidromically fired from the cerebellum). Of these, 66 neurons altered their spontaneous firing rates in response to cortical stimulation. Two patterns of responses were found: either an excitation followed by a suppression of spontaneous activity (52 neurons), or a pure suppression of spontaneous activity lasting 50-400 msec (14 neurons). In 46 of these neurons, it was found that cortical stimulation reduced HS-evoked activity to near the baseline level. Furthermore, it was found that when applied after a prolonged cortical stimulation, the HS was ineffective. It is concluded that FPSM cortex can influence nociceptive information in LRN neurons that respond to its stimulation, possibly interfering with the mechanisms underlying stimulation-produced analgesia (SPA). In this context, it is proposed that the cortex can modulate the activity of LRN neurons that activate, through local loops, a descending antinociceptive system and also a separate projection system to the cerebellum.     

Stimulation of transepithelial sodium and chloride transport by ascorbic acid. Induction of Na+ channels is inhibited by amiloride

Ascorbic acid increases the short circuit current (I_sc) across the amphibian cornea when it is present at either surface of this epithelium. These effects were additive. The effect was greater when it was on the tear side. The response returned to baseline levels when the ascorbic acid was washed from the bathing media. The effect of ascorbic acid on I_sc when it was on the aqueous humor side of the cornea could be blocked by bumetanide but that due to the vitamin's presence on the tear side was unchanged. The ascorbic acid could enter the tissue and crossed the cornea at similar rates in either direction. When the cornea was bathed by a Cl^?-free solution or exposed to bumetanide, the rise in I_sc observed with ascorbic acid on the tear side was equivalent to an increased Na⁺ flux from the tear to the aqueous humor side. In normal (Cl^? present) Conway solution the rise in the I_sc seen with ascorbic acid on the aqueous humor side was equal to an increased flux of Cl^? from the aqueous to the tear surface. However, when ascorbic acid was present on the opposite, tear, side the increased I_sc reflected a rise in both Cl^? and Na⁺ transport, aqueous-to-tear side, and tear-to-aqueous side, respectively. Thiol reagents (tear side), including reduced glutathione (10^?5 M), blocked the effect of ascorbic acid (10^?3 M) providing they were added to the bathing solution prior to the vitamin. However, they had no effect once the response had been established. The effect of the reduced glutathione appeared to be of a non-competitive nature. Oxidized glutatione (10^?4 M) (and cystamine) blocked the effect of ascorbic acid (10^?3 M) when present on the tear side prior to the vitamin. However, they also increased the rate of decline of the response when added subsequently to the ascorbic acid. Amiloride (as low as 5·10^?9 M), on the tear side but not the aqueous humor side, prevented the response to ascorbic acid but could not reverse it, once it was established. The possible nature of the effect of ascorbic acid is discussed in relation to its pharmacological interactions with thiol and disulfide reagents and amiloride.