Fertilization and early embryology: Intracytoplasmic sperm injection does not overcome an oocyte defect in previous fertilization failure with conventional in-vitro fertilization and normal spermatozoa

A cohort comprising a total of 447 oocyte aspirations due tomale factors (n±258) or to previous fertilization failureby IVF in the presence of normal sperm parameters (n±189)was studied. We found a significantly reduced implantation andpregnancy rate per transfer in the group with previously failedIVF attempts compared to the male factor group (P <0.001).No differences were found in age, number of oocytes retrieved,number of embryos transferred or quality of embryos scored atthe time of transfer. However, the fertilization and cleavagerates were found to be reduced in the group with previous failedIVF cycles. It is therefore concluded that previous fertilizationfailure despite normal sperm parameters in an 1VF cyde may notbe alleviated by the intracytoplasmlc sperm injec tion (ICSI)procedure. These patients might suffer from oocyte defects aswell.     

Effects of oxytocin and a derivative (Z-prolyl-D-leucine) on morphine tolerance/withdrawal are mediated by the limbic system

Recent data indicate that the neurohypophyseal hormone oxytocin (OXT) and Z-prolyl-D-leucine (Z-Pro-D-Leu), a synthetic dipeptide derived from the C-terminal part of OXT, attenuate the development of tolerance to and dependence on morphine in the mouse. Biochemical and behavioral data raise the possibility that these effects of the peptides might be associated with their effects on the central nervous system and in particular on limbic brain structures. The present results confirm this hypothesis, since intracerebroventricular (i.c.v., 50 ng) and local (0.5 ng) injections of OXT and Z-Pro-D-Leu into the dorsal hippocampus and the mesolimbic nucleus accumbens attenuate morphine tolerance/dependence, similarly to systemic injections of these peptides in higher amounts (5-50 micrograms). Local injections of these peptides into other brain sites (e.g. the nucleus caudatus, ventral tegmental area and the external cortical surface) are without effect. Lesion of the nucleus accumbens by the catecholaminergic neurotoxin 6-hydroxydopamine (6-OHDA) completely prevents the effects of Z-Pro-D-Leu and partially those of OXT on morphine tolerance/dependence. The data point to the role of limbic structures as mediators of the effects of neuropeptides on morphine addiction.     

The Effects of Activation or Inhibition of the Subthalamic Nucleus on the Metabolic and Electrophysiological Activities Within the Pallidal Complex and Substantia Nigra in the Rat

The changes in local cerebral glucose utilization (LCGU) and neuronal unit activities in the subthalamic nucleus and its major target structures (the pars reticulata of the substantia nigra, the globus pallidus and the entopeduncular nucleus) following microinjection of a GABAergic antagonist (bicuculline methiodide, 0.08 nmol) or agonist (muscimol, 0.2 nmol) into the subthalamic nucleus were determined. The metabolic effect was assessed by measuring LCGU by quantitative [14C]-2-deoxyglucose autoradiography in ketamine-anaesthetized rats. Bicuculline methiodide induced increased LCGU in the ipsilateral globus pallidus, the entopeduncular nucleus and the substantia nigra pars reticulata. In contrast, muscimol decreased LCGU in these structures. The neuronal activities in the subthalamic nucleus and related structures increased following injection of bicuculline and decreased after injection of muscimol. The changes in LCGU within the structures directly related to the subthalamic nucleus were correlated with the changes in the unit activity either in the subthalamic nucleus and/or its projection structures. However, the amplitude of the relative changes in neuronal unit activity were greater than the changes in LCGU. Nevertheless, the results emphasize the functional role of the subthalamic nucleus as an activating structure within the basal ganglia.     

胞内精子注射法制备转基因爪蟾的研究

目的研究爪蟾胞内精子注射法(intracytoplasmic sperm injection,ICSI)转基因技术的可行性。方法取成熟雄蛙的睾丸分离纯化精子,用毛地黄皂甙(digitonin)崩解精细胞膜并制备精子浓缩液,然后与线性化报告基因载体pCMV-EGFP-N1共处理,最后将处理后的精子注射入从雌性爪蟾体内取出的未受精卵中,培养并观察。结果制备的精子质量较高,稀释的精子注射入未受精卵后,卵的受精率为10%,受精卵活过神经胚的比率为20%,但都略微有点畸形。其中,绿色荧光报告基因EGFP的整合率为81%,但镜下未见绿色荧光蛋白的表达。结论ICSI法是制备转基因爪蟾的简便可行的新途径。     

Characterization of mRNA responsible for induction of functional sodium channels in Xenopus oocytes

When Xenopus laevis oocytes were microinjected with poly(A)+ mRNA isolated from adult rat brains or electric organs of Electrophorus electricus, the oocytes developed functional sodium channels. Upon application of veratrine, the microinjected oocytes exhibited transient depolarization, resulting in spontaneous repetitive spikes in some occasions, and action potentials. These responses were mediated mainly by external Na ions, prolonged by scorpion toxin, completely blocked by tetrodotoxin, and suppressed by local anesthetics. Thus the mRNA-induced sodium channels exhibited essentially all the functional properties expected for native sodium channels in nerve and muscle membranes. Rat brain mRNA was fractionated into 4 fractions by sucrose gradient centrifugation. Each fraction and various combinations of them were examined for the efficiency in inducing functional sodium channels in Xenopus oocytes. A fraction corresponding to mRNA of approximately 30S to 46S was found to contain all mRNA necessary for the expression of the channels, indicating that mRNA of smaller sizes expected to code for smaller polypeptides may not be required.     

II. Examination of spinal monoamine receptors through which brainstem opiate-sensitive systems act in the rat

Microinjection of morphine (5 μg) through stereotaxically implanted microinjection cannulas into the periaqueductal gray (104 sites), medial (n. raphe magnus; 26 sites) and paramedial (n. reticulogigantocellularis; 49 sites) medulla resulted in an increase in the latency of supraspinally (hot-plate) and spinally (tail-flick)-mediated responses evoked by thermal stimuli. This effect of intracerebral morphine on both hot-plate and tail-flick was dose-dependent, and reversed by systemically administered naloxone as well as by naloxone administered by microinjection into the same site. On the basis of frequency of occurrence, time of onset and magnitude of effect of the minimum effective dose, we could demonstrate no difference between the efficacy of morphine acting at sites in the periaqueductal gray, n. raphe magnus or n. reticulogigantocellularis on the supraspinally mediated response. In all areas examined, morphine was able to produce the maximum elevation in response latency. The microinjection of morphine into the periaqueductal gray frequently produced a total block of the thermally evoked spinally mediated tail-flick reflex. Unlike the periaqueductal gray, the systems through which opiates act in the n. raphe magnus or the n. reticulogigantocellularis to suppress spinal reflex activity displayed a clear plateau in their physiological effects. Microinjections of morphine into the n. raphe magnus or n. reticulogigantocellularis never produced a complete block of the spinal reflex. Further increases in inhibition could not be achieved by either a 3-fold increase in dose or bilateral injections into the paramedial medulla. The failure to block spinal reflex activity often occurred at sites where morphine would completely block the hot-plate response. These observations indicate that opiate receptor-linked systems in the mesencephalon and medulla can significantly attenuate the coordinated escape behavior otherwise evoked by a high-intensity thermal stimuli. We find there is no difference in the physiological efficacy of morphine acting in those regions on supraspinally mediated measures of pain responding. The differential effect on spinally mediated reflex function suggests that these several opiate linked systems produce their effect by discriminable mechanisms.     

Non-opiate analgesia induced by carbachol microinjection into the pontine parabrachial region of the cat

These studies investigated the effect of microinjection of the cholinergic agonist carbamylcholine (carbachol) into various sites of the dorsolateral pontine tegmentum of the cat. Carbachol microinjection into an area surrounding the lateral half of the brachium conjunctivum (parabrachial region, PBR) produced profound suppression of nociceptive responses. In the dorsal part of PBR, carbachol microinjection produced no generalized sensory, emotional or motor deficits, indicating that nociceptive transmission was primarily affected. Carbachol microinjection into the ventral part of PBR resulted in slight suppression of motor responses in addition to profound nociceptive suppression. Carbachol-produced analgesia (CPA) observed within PBR blocked supraspinally as well as spinally integrated responses normally elicited by either phasic or tonic noxious stimuli. Atropine sulfate, but not mecamylamine hydrochloride, significantly antagonized CPA, indicating that muscarinic receptors mediate this phenomenon. The opiate antagonist naloxone, systemically administered either prior to or after carbachol microinjection, did not reliably attenuate CPA. Microinjection of morphine into the sites from which CPA had previously been obtained did not produce significant effects on nociceptive responses. Thus, opiate mechanisms appear not to be necessary either for the activation of this system or for the production of the resultant analgesia. These findings indicate that the neural population examined in the present study is anatomically and pharmacologically distinct from previously identified opiate-mediated pain inhibitory systems. Results are discussed in light of other recent evidence indicating the existence of endogenous non-opiate pain inhibitory systems.     

随机模糊神经网络在DNA微注射量信息融合控制中的应用

气压电控式DNA微注射量单因素控制方案中存在准确性较差的问题。本研究提出了一种基于随机模糊神经网络的微注射量多信息融合的控制方案，实现了注射压力、注射时间，以及微注射针尖端径等多种参数的信息融合控制。实验结果表明，较之单因素控制方案，本法的控制精度得到较大改善，而且对于参数测量中存在的噪声污染由较强的抗干扰能力。     

GAP-43高表达转基因小鼠的建立

目的构建GAP-43(growth associated protein-43)高表达转基因小鼠,为进一步研究GAP-43对神经发生及损伤修复的作用机制提供基础。方法构建pCEP4-PDGF-GAP-43转基因构件,通过原核显微注射方法将线性化、纯化后的外源质粒pCEP4-PDGF-GAP-43注射入C57小鼠受精卵中,胚胎移植至同期发情的假孕受体母鼠输卵管内,获得子代小鼠。用PCR方法检测子代鼠尾基因组DNA,通过Western blotting法检测GAP-43基因表达,并通过免疫荧光的方法对GAP-43表达位置进行定位。结果经PCR方法检测得到转基因阳性鼠,Western blotting结果显示GAP-43蛋白的表达量高于同胞对照组的小鼠且差异有统计学意义,免疫荧光染色结果显示GAP-43阳性反应物弥散分布于大脑皮质和海马中,且特异性存在于神经元中。结论外源基因GAP-43在小鼠基因组中得到整合并稳定遗传,为神经损伤修复及神经发育的相关研究提供了有价值的动物模型。     

Influences of entopeduncular nucleus stimulation upon electromyogram activity of masticatory muscles

Influences of stimulation of the entopeduncular nucleus (Ep) upon electromyogram (EMG) activity of masticatory muscles were examined. In the rat lightly anesthetized with halothane, high frequency (HF) microstimulation (trains of 20, 333-Hz cathodal pulses at 30-60 muA) and GABA microinjection (0.2-0.6 mul of 10 mM GABA dissolved in physiological saline) were performed in the Ep by using a three-barreled microelectrode. EMG activity was recorded from the anterior digastrics and the anterior superficial masseter muscles by using two fine enamel-insulated copper wires. The EMG activity was also evoked by the GABA microinjection. The effect of the GABA microinjection was negated by the microinjection of bicuculline prior to the GABA microinjection. The EMG activity was classified into the tonic spike-type, burst-type, or mixed type on the basis of the waveform. In each rat, the location of the microelectrode tip was estimated by observing a series of serial frontal sections through the whole rostrocaudal extent of the Ep. The present data suggested that Ep neurons involved in elicitation of tonic spike-type activity in the jaw muscles might be located mainly in the rostral third of the Ep, and that Ep neurons implicated in provocation of burst-type activity in jaw muscles might be located in the caudal third of the Ep. Possible neuronal pathways from the Ep to motoneurons innervating the masticatory muscles were discussed. The present data shed new light on the control mechanisms of the basal ganglia upon jaw movements.