Facilitation of mounting behavior in male rats by intracranial injections of luteinizing hormone-releasing hormone

Luteinizing hormone-releasing hormone (LH-RH) administration has been reported to facilitate male sex behavior. This laboratory has previously reported development of the ‘mounting test’, a paradigm which reflects sexual arousal mechanisms. We have used this test to study the interaction of LH-RH with the central components of male copulatory behavior in the rat.Sixty 90-day-old Long-Evans male rats were screened for sex behavior and divided into 5 treatment groups. For all mounting tests, a local anesthetic was applied to the penis and mounts were scored during a 15-min exposure to a stimulus female. The animals were given 3 successive weekly tests. By the final test, a significant decrement in mounting behavior was noted, and those males given 50 ng LH-RH i.c.v. displayed more mounting in this test than animals given either no treatment or saline ($\text{P < 0.01}$). A slight but significant ($\text{P < 0.05}$) enhancement of performance was also noted in peptide-treated rats in test I. There was no significant difference in any of the tests between animals given lateral cerebroventricular (i.c.v.) injections of 2 μl acidified saline and those given no treatment. When blood samples were taken from similarly treated animals and assayed by radioimmunoassay for luteinizing hormone and testosterone, plasma levels of these hormones were not different at either 30 min or 2 h after injection of saline or LH-RH.Thus, in animals with diminished genital sensory input, LH-RH administration increases mounting behavior without inducing measurable reproductive endocrine changes. It is proposed that this effect results from an interaction of this peptide with the neural substrates of the arousal mechanism.     

Cloned goats (Capra hircus) from adult ear cells

The average number of available oocytes recovered per ovary collected during the breeding season in dairy goats was 5.5 (1815/330). 66.17% (1201/1815) of oocytes extruded the first polar body after maturation in vitro for 20 h. 75.44% (906/1201) of matured oocytes with membrane evagination around the MⅡchromosomes were enucleated. Ear skin fibroblast cells were derived from an adult female Jining Grey goat (C. hircus). The cells were cryopreserved in liquid nitrogen after passage 2. Thawed cells were further cultured for 3-6 passages and were subjected to serum starvation by 0.5% FBS for 2-10 d, then used as donor cells for nuclear transfer. 98.12% (889/906) of the enucleated oocytes were reconstructed by intracytoplasmic injection of karyoplast. The reconstructed embryos were activated by 5 μmol/L ionomycin for 4.5 min and further activated by culturing with 6-dimethylaminopurine (6-DMAP) for 3 h. After 36 h of culture in mCR1aaBF, 76.69% (645/841) of the cloned embryos cleaved. There were no significant differences in development in vitro between the cloned embryos derived from donor cells precooled at 4℃ for 24 h and nonprecooled donor cells. The cleavage rates, 4-cell development, and blastocyst development of reconstructed embryos were 72.48% (79/109), 53.16% (42/79), and 19.05% (8/42) in precooled group; 68.5% (211/308), 59.72% (126/211), and 17.46% (22/126) in nonprecooled group, respectively. Eighteen cloned 4-cell embryos derived from precooled donor cells were transferred and one cloned kid was born. Eighty-four cloned 4-cell embryos derived from nonprecooled donor cells were transferred and no offspring were produced. Of 18 cloned morale from nonprecooled donor cells transferred, one kid was born. The results of microsatellite DNA analyses indicated that the two cloned kids were from the same donor fibroblast cell line derived from an adult goat ear skin.     

Determination of l-glutamate in various commercial soy sauce products using flow injection analysis with a modified electrode

A flow injection analysis (FIA) system with a modified electrode has been developed and optimized for determination of l-glutamate using l-glutamate oxidase (GLOD) (EC 1.4.3.11). GLOD was immobilized on controlled-pore glass using glutaraldehyde. The optimal potential applied on the working electrode was +700mV against a platinum (Pt) reference electrode. The optimal pH and flow rate of the carrier buffer were 7.4 and 1.5ml/min, respectively. A modified electrode was integrated into the FIA system in order to eliminate electroactive interference and it was used to determine l-glutamate in 39 samples of Thai commercial soy sauce products. The results obtained were compared with those obtained from enzymatic assay using glutamate dehydrogenase and those from a chromatographic assay using an amino acid analyser. Good correlations were observed amongst these methods. The results indicated that use of an FIA system with a modified electrode was able to eliminate electroactive interference and was applicable to the determination of l-glutamate in food samples. The modified FIA was faster and simpler than the more common methods of enzymatic and chromatographic analysis.     

Use of a micro-expanded bed containing immobilised lysozyme for cell disruption in flow injection analysis

A method for cell disruption in Flow Injection Analysis (FIA) systems has been developed. The principle involves on-line cell disruption by means of immobilised lysozyme followed by an ultrasonic treatment. In order to avoid flow problems in the analytical system, the lysozyme was immobilised to Streamline^reg that was used in an expanded bed in the flow system. Samples of suspensions of Micrococcus lysodeikticus were treated and the success of the treatment was evaluated in terms of released protein and as a decrease in the optical density at 450 nm. The new technology offers a powerful tool in flow injection analyses for quantification of intracellular compounds. The concept of integration, i.e. combining cell disruption with handling of cell debris and assay procedure in one continuous flow process facilitates its use and increases the probability of reaching reproducible and reliable results.     

A fluorescence-based fiber optic biosensor for the flow-injection analysis of penicillin

A penicillin fiber optic sensor is described. The sensor is based on co-immobilization of a pH indicator, fluorescein isothiocyanate (FITC), and penicillinase on a preactivated biodyne B membrane attached to the end of a bifurcated optical fiber. The characteristics of the sensor are investigated in conjunction with a flow injection analysis system. The proposed sensor is reversible and responds to penicillin in the concentration range of 1 x 10(-4) to 5 x 10(-2) mol/L. The application of this sensor to penicillin analysis in some pharmaceutical samples is demonstrated.     

A low temperature microbial biosensor using immobilised psychrophilic bacteria

A psychrophilic bacteria, Deinococcus radiodurans, was used to construct a biosensor to be used in a flow injection system. The transducer used was an O₂ electrode. The response of this cell-based electrode was studied towards a number of sugars. The temperature dependence of the electrode response correlated well with the behavior of the cells. Thus, the optimum temperature for measurement of glucose (0.55 mM) was about +5°C. Since the organism used is psychrophilic, a response time at this low temperature is similar to what is achieved with mesophilic organisms at room temperature. This is the first biosensor constructed using a psychrophilic microorganism.     

P物质在脊髓水平对心血管活动的影响

为阐明起源于延髓,下行达脊髓侧角的P物质(SP)纤维在心血管活动中的作用,我们在乌拉坦麻醉的大鼠上进行了以下实验:(1)在完整大鼠脊髓蛛网膜下腔注射(ith)SP(15nmol/10μl),观察到内脏交感神经放电、心率及平均动脉血压均有明显升高。(2)在颈_1(C_1)横断脊髓的大鼠,ith 相同剂量相同体积的SP 却引起内脏交感神经放电及平均动脉血压轻度下降,心率稍有增加。(3)C_1 横断脊髓的大鼠静脉注射相同剂量的SP 则引起平均动脉血压急速降低及内脏交感神经放电增加,提示SP 在脊髓水平的直接作用系通过抑制交感传出放电而引起血压降低。(4)用ith PS 的1/10剂量、1/5体积给完整大鼠脑池注射(ici),观察到血压及内脏交感神经放电增加,但心率没有变化。 上述结果表明,(1)SP 作用于脑和脊髓,对心血管功能可能有不同的作用。(2)ith SP对完整大鼠心血管功能的作用是多途径的。     

Determination in serum of some barbiturates using micellar liquid chromatography with direct injection

A procedure was developed for the determination of several barbiturates, amobarbital, barbital, hexobarbital, and secobarbital, using a C18 column (120 x 4.6mm) and micellar liquid chromatography (MLC) mobile phases containing sodium dodecyl sulfate (SDS) and propanol, butanol, or pentanol as a modifier, with UV detection at 230nm. After the application of an interpretative strategy of optimization, the four barbiturates can be resolved and determined in serum samples, allowing the direct injection in 0.10M SDS-4% (v/v) butanol, pH 7, with an analysis time below 8 min. In the proposed MLC procedure, linearities (r >0.999), limits of detection (ngmL(-1)) in the 30-70 range, repeatabilities, and intermediate precision below 1.8% are adequate for the quantification. The proposed method could be applied to the determination of barbiturates in serum samples with recoveries that agreed with the concentration added.     

Flow injection chemiluminescence determination of captopril based on its enhancing effect on the luminol–ferricyanide/ferrocyanide reaction

A new flow injection chemiluminescence method is described for the determination of captopril. It is based on the enhancing effect of captopril on the chemiluminescence reaction of luminol with potassium ferricyanide in alkaline solution in the presence of potassium ferrocyanide. The method allows the determination of captopril over 0.1–40 µg/mL range, with a relative standard deviation (SD) of 1.0% for the determination of 0.5 µg/mL captopril solution in 11 repeated measurements. The method was satisfactorily applied to the determination of captopril in commercial captopril tablets. The possible reaction mechanism is also discussed briefly. Copyright © 2002 John Wiley & Sons, Ltd.