部分背根切断对备用背根节NT-3表达的影响

目的　探讨部分去背根后备用背根节 (L6 )各类细胞NT 3及其mRNA的含量变化。　方法　对成年雄性猫行单侧部分背根切断术 (切除一侧L1 ～L5,L7～S2 DRG ,保留L6 为备用根 )。取正常组一侧和术后 3d及 7d组手术侧的L6 DRG制作 2 0 μm厚冰冻切片 ,分别用NT 3抗体及NT 3cRNA探针行免疫组织化学及原位杂交染色。观察NT 3及其mRNA在DRG各类细胞的分布 ,测定NT 3及其mRNA在神经元和卫星细胞的光密度值 ,所得数据用q检验进行统计分析。　结果　部分去背根后 ,各时相备用背根节大神经元内NT 3的光密度值较正常者进行性减少 ,(P <0 0 5 ) ,而NT 3mRNA的光密度值术后 3d减少 ,7d回升至近正常者水平。比较之 ,小神经元和卫星细胞NT 3及其mRNA的光密度值进行性增多 (P <0 0 5 )。　结论　部分背根切断对备用背根节各类细胞NT 3表达的影响不同 ,其功能意义可能与NT 3参与脊髓Ⅱ板层可塑性有关     

家兔内脏大神经传入神经元的节段分布

为探明内脏大神经传入神经元在后根节内的节段分布,本研究将家兔的左侧内脏大神经中枢侧断端浸泡于HRP溶液中。其HRP标记细胞的节段范围为胸_2——胸_(12)节,并以胸_5——胸_(11)节为多。91.2%HRP标记细胞的直径在34微米以下。     

Cannabinoid agonist, CP 55,940, facilitates intake of palatable foods when injected into the hindbrain

Cannabinoids have been shown to influence food intake, and until recently, the neural pathways mediating these effects have remained obscure. It has been previously shown that intracerebroventricular injection of delta-9-tetrahydrocannabinol (Δ⁹-THC) causes increased consumption of palatable foods in rats, and we postulated the involvement of the hindbrain in this cannabinoid-induced food intake. Cannulated rats (both female and male groups) trained to consume sweetened condensed milk received either lateral or fourth ventricle injections of CP 55,940 and were presented with sweetened condensed milk 15 min after injection. Rats were injected over a range of doses between 100 pg and 10 μg per rat. Milk intake was recorded for a total of 3 h. Lateral ventricle injection of CP 55,940 increased milk intake at doses in the microgram range. However, CP 55,940 was effective in increasing food intake at nanogram doses when injected into the fourth ventricle. Finally, male rats appeared to be more sensitive to CP 55,940 than female rats inasmuch as milk consumption was increased at the 1 ng dose in male rats, whereas only the 10 ng dose was effective in females. These results indicate that CP 55,940 may act in the hindbrain to influence feeding behavior in rats.     

Evidence for Presence of Types A and B of Beet Necrotic Yellow Vein Virus (BNYVV) in Iran

Rhizomania a viral disease, caused by beet necrotic yellow vein benyvirus (BNYVV), is now widely spread, throughout the sugar beet growing areas of Iran. Genomes of BNYVV are composed of five RNA molecules with specific functions. In this study sequence analyses were conducted on the major coat protein gene (CP21), and parts of RNA3 and RNA4 of an Iranian strain of BNYVV from the Fars province. Sequence alignments of Iran Fars CP21 with other isolates showed closed similarities at nucleotide and amino acid levels with BNYVV pathotype A isolates; S from Japan, and YU2 from Yugoslavia. These results suggest that Iran-Fars isolate probably originated from Asia or neighboring European countries rather than from Germany or France.     

Displaced retinal ganglion cells project to the accessory optic system in the chameleon ( Chamaeleo calyptratus)

Retinal ganglion cells were successfully labelled in the chameleon by retrograde axonal transport of dextran amines that were applied to the nucleus of the basal optic root (nBOR) in an in vitro preparation. Labelled ganglion cells were restricted to the contralateral eye. Many cells were completely stained including their dendritic trees. With few exceptions, all cells had displaced somata that were located at the inner margin of the inner nuclear layer. The labelled ganglion cells had two to six primary dendrites that branched frequently and formed large unistratified dendritic trees within sublamina 1 of the inner plexiform layer. There was extensive overlap of the dendritic trees of neighbouring cells leading to an estimated coverage factor of 2-4. The dendritic field areas varied in size according to the retinal position of the cells and were highest in the central retina around the fovea with a maximum of 0.14 mm(2) and reached a second maximum at the retinal margin with values of 0.08-0.1 mm(2). The smallest dendritic areas (0.04-0.06 mm(2)) were measured midway between the fovea and retinal margin. The size of the soma area was not correlated to the dendritic field size and increased from 100 to 150 microm(2) near the fovea to 150-300 microm(2) at the retinal margin. There was no evidence for a retinotopic organisation of ganglion cell fibres within the nBOR. All cells were of uniform morphology that was identical to the type of nBOR-projecting displaced ganglion cell (DGC) described previously for the bird retina. Similar to birds, the labelled DGCs were the only source of retinal projection to the nBOR. A small fraction of cells had orthotopic somata located in the ganglion cell layer but were otherwise identical to the labelled DGCs. The similarity of chameleon nBOR-projecting ganglion cells to those described in avian retinas mirrors the close phylogenetic relationship of birds and lizards.     

The three-dimensional microvascular arrangement around rat dorsal hairs as revealed by scanning electron microscopy

The three-dimensional microvascular arrangement around the dorsal hairs in vascular corrosion casts of adult Wistar rats was studied by scanning electron microscopy. Each anagen dorsal hair was surrounded by a basket-like capillary network, which was supplied by the branches of the subcutaneous artery and drained into the veins continuous with the subcutaneous vein. The capillary network surrounding the anagen dorsal hair was denser at its lower part, and became more sparse at its upper part. Transmission electron microscopy showed that the capillaries around the hair bulb possessed fenestrations. Our findings indicate that the microvascular arrangement around the anagen dorsal hair is so organized as to supply the hair bulb, which is the most important area for hair growth, with abundant blood. This study was presented at the 24th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Okayama, September 17–19, 1992.     

Ultrastructural identification of synaptic terminals from cortical axons and from collateral axons of geniculo-cortical relay cells in the perigeniculate nucleus of the cat

Summary Electron microscopic analysis of sections of the perigeniculate nucleus (PGN) of the cat processed with horseradish peroxidase (HRP) histochemistry after massive injections of this enzyme in the visual cortex showed two types of synaptic terminals labeled with HRP reaction products. One type (RLD terminals) is characterized by round synaptic vesicles, large size, dark mitochondria and asymmetrical synaptic contacts with somata and dendrites. The second type (RSD terminals) is characterized by round synaptic vesicles, small size, dark mitochondria and asymmetrical synaptic contacts with dendrites. The HRP + RSD terminals, which were also found in the dorsal lateral geniculate nucleus (LGN), are interpreted as terminals of cortical origin both in the PGN and LGN, since previous studies have identified cortical terminals as being of RSD type in the LGN and in other thalamic nuclei. The HRP + RLD terminals are interpreted as synaptic terminals of collaterals axons of geniculo-cortical relay cells in the PGN labeled by retrograde transport of HRP from the cortex. In addition, in semithin and ultrathin sections somata in the PGN were never found labeled with HRP products indicating the absence of a PGN projection to the visual cortex.     

外周神经损伤大鼠背根神经节中Ephrin B1及RYK 受体表达的变化

目的研究外周神经损伤后背根神经节细胞中Ephrin B1及其相关受体的表达变化。方法建立一侧坐骨神经夹伤的大鼠动物模型,通过免疫荧光组织化学方法检测受损侧背根神经节细胞中Ephrin B1及其相关受体Eph B1、Eph B2、Eph B3和Eph A4、RYK等的表达,并分析阳性细胞数和不同大小阳性细胞的构成比例。结果外周坐骨神经受损侧背根神经节细胞中Ephrin B1的表达明显减弱,而Eph B1、Eph B2、Eph B3和Eph A4受体的表达无明显变化,但RYK受体的表达则明显加强。结论Ephrin B1和RYK受体在一侧外周坐骨神经夹伤后的大鼠背根神经节细胞中表达的变化,说明它很有可能参与了损伤后的功能活动。     

Dihydropyridine inhibition of neuronal calcium current and substance P release

Dihydropyridine (DHP) calcium channel antagonists, which inhibit the slowly inactivating or L-type cardiac calcium (Ca) current, have been shown to be ineffective in blocking⁴⁵Ca influx and Ca-dependent secretion in a number of neuronal preparations. In the studies reported here, however, the antagonist DHP nifedipine inhibited both the L-type Ca current and potassium-evoked substance P (SP) release from embryonic chick dorsal root ganglion (DRG) neurons. These results suggest that, in DRG neurons. Ca entry through L-type channels is critical to the control of secretion. The inhibition of Ca current by nifedipine was both voltage and time-dependent, significant effects being observed only on currents evoked from relatively positive holding potentials maintained for several seconds. As expected from these results, nifedipine failed to inhibit L-type Ca current underlying the brief plateau phase of the action potential generated from the cell's normal resting potential; likewise, no significant effect of the drug was observed on action potential-stimulated SP release evoked by electrical field stimulation. The results of this work are discussed in terms of an assessment of the role of L-type Ca channels in neurosecretion.This work was supported by United States Public Health Service Grant NS16483 (KD) and by a USPHS Postdoctoral Fellowship (SGR)     

Adjunctive low-dose doxycycline therapy effect on clinical parameters and gingival crevicular fluid tissue plasminogen activator levels in chronic periodontitis

Objective and design: The present study examined effectiveness of low-dose doxycycline (LDD) in combination with nonsurgical therapy on gingival crevicular fluid (GCF) tissue plasminogen activator (t-PA) levels and clinical parameters in chronic periodontitis (CP) a over 12-month period. Methods: GCF samples were collected, probing depth (PD), clinical attachment level (CAL), gingival index (GI) and plaque index were recorded at baseline, 3, 6, 9 and 12 months. CP patients (n = 65) were randomized to LDD or placebo groups. LDD group received LDD (20 mg) b.i.d for 3-months plus and root planing (SRP), while placebo group was given placebo capsules b.i.d for 3-months plus SRP. GCF t-PA levels were determined by ELISA. Friedman, Wilcoxon and Mann-Whitney test was used for statistical analysis. Results: Significant improvement was observed in all clinical parameters in both groups over 12-month period (p < 0.01). LDD group had lower PD, CAL and GI scores than placebo group at 6, 9 and 12-months (p < 0.05). GCF t-PA levels reduced in both groups over 12-month period (p < 0.01). LDD group had lower GCF t-PA levels than placebo group at 6 and 9-months (p < 0.05). Conclusions: These results provide additional information about usefulness of LDD therapy as an adjunct to nonsurgical therapy in long-term management of periodontitis. Received 8 May 2006; returned for revision 13 June 2006; accepted by J. Di Battista 12 July 2006