The effect of SHF waves on the evoked potentials in the cat spinal cord

In experiments with adult cats there revealed a pronounced effect of SHF radiation on the electrogenesis of spinal cord, the beam density being 15 mW/cm2 and time of exposure 10 min. The estimates of the induced somatosensory brain potentials indicate that there is a phase of a 20 per cent response inhibition with the effect reaching maximum 2-3 h following irradiation. Subsequently, potential characteristics are exponentially restored to be the same with the control values. The evidence is presented that the synaptic neuron contacts within the reflex arc are highly susceptible to SHF radiation.     

长毛红山茶和长尾红山茶的核型分析

<正> 长毛红山茶(Camelliav uillosa Chang et S.Y.Liang)和长尾红山茶(C.longicaudata Chang et S.Y.Liang)均为张宏达教授定的新种,分别隶属于山茶属(Camellia)红山茶组(Sect.Camellia)的滇山茶亚组(Subsect.Reficulala)和光果红山茶亚组(Subsect.Lucidissima),前者分布在我国的湖南、广西和贵州,后者分布在广东和广西。 红山茶组共有33个种、1个亚种,7个变种。根据文献资料统计,该组作过染色体计数的有10个种,1个亚种和6个变种,作过核型分析的有4个种、1个亚种和2个变种。本文对该组的长毛红山茶和长尾红山茶的核型作首次报道,并与该组的10个种,1个亚种和6个变种的染色体数目或核型作了比较。     

The use of fetal mouse spinal cord-dorsal root ganglion explants to study the factors underlying selective connections in vitro

Dorsal root ganglion (DRG) afferents selectively project to dorsal spinal cord (SC) explants when grown in a medium containing serum or a serum-free medium (CDM) containing galactose compounds. SC-DRG explants grown in CDM retain their gross morphological characteristics over several months in vitro, greatly facilitating the mapping of the sensory afferents within given regions of the cord explant. Explants grown in CDM without the addition of galactose show no such selective preference for dorsal cord, and terminate equally throughout the cord. This lack of selectivity also occurs in galactose-grown SC-DRG provided tetrodotoxin (TTX) is added to the medium sufficient to block all recordable spontaneous bioelectric activity (SBA), viz., action potential discharges and slow waves. Gangliosides are galactose-containing compounds found in neural membranes which may be involved in cell-cell recognition/adhesion. The addition of a mixture of gangliosides to the CDM results in the preferential restriction of the sensory afferents within the dorsal cord regions even in the presence of TTX. It is concluded that gangliosides may be able to compensate for the absence of SBA during periods of development associated with the formation of selective interneuronal connections.     

Altered gene expression of NIDD in dorsal root ganglia and spinal cord of rats with neuropathic or inflammatory pain

Nitric oxide and nitric oxide synthases are key players in synaptic plasticity events in spinal cord (SC), which underlies the chronic pain states. To date, little is known about the molecular mechanisms regulating the activity of nitric oxide synthases in nociceptive systems. The present study was aimed at the determination of the gene expression of nNOS-interacting DHHC domain-containing protein with dendritic mRNA (NIDD), a recently identified protein regulating nNOS enzyme activity, in rat SC and dorsal root ganglia (DRG) and studying its regulation in states of nociceptive hypersensitivity in a rat model of neuropathic or inflammatory pain. It was found that NIDD mRNA was predominantly expressed in nociceptive primary neurons and in neurons of the spinal dorsal horn (DH) and the number of NIDD-positive neurons in the corresponding DRG or SC increased significantly following induction of chronic hyperalgesia. Meanwhile, remarkable changes of nNOS were detected under such pain conditions. Our data suggest a potential role for NIDD in the maintenance of thermal pain hypersensitivity possibly via regulating the nNOS activity. Meng-Ling Chen and Chun Cheng are contributed equally to this work.     

Chromosome number and modal karyotype in a polysomatic endangered orchid, Bulbophyllum auricomum Lindl., the Royal Flower of Myanmar

A detailed account is presented of attendant polysomatic variation in planta and elucidation of the modal karyotype in the difficult-to-study endangered orchid Bulbophyllum auricomum, known as the Royal Flower of Myanmar. The somatic chromosome number of B. auricomum (2n?=?38) is reported for the first time. Polysomaty was prevalent in all seed-derived plants studied except two (SC34 and SC42). It was noted that in addition to normal diploid cells occurring in different frequencies (60% in SC21 to 89% in SC22, SC35), root tip cells also showed chromosome numbers <38 (in 0?C37% metaphases) and >38 (in 0?C33% metaphases). The chromosomes of B. auricomum are very small (0.7?C2.7???m) in size. The karyotype of diploid B. auricomum showed 34 chromosomes with primary constriction (14?M?+?16?m?+?4sm) and 4 chromosomes with secondary constrictions (sm:sm). Of the 50 plants analyzed, 2 (SC34 and SC42) were polyploid, showing 70 and 62 chromosomes in the root tip cells. The polyploidization in seed-derived plants clearly indicates the heterogeneous nature of orchid seed stock. Early detection of polyploidization in in vitro?Cpropagated B. auricomum is valuable for conservation of this native endangered orchid species. On the other hand, the clonally propagated plants retained the chromosomal status of parent plants. This protocol could be exploited to protect this native endangered orchid species from natural extinction.     

Recent advances in production of succinic acid from lignocellulosic biomass

Production of succinic acid via separate enzymatic hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) are alternatives and are environmentally friendly processes. These processes have attained considerable positions in the industry with their own share of challenges and problems. The high-value succinic acid is extensively used in chemical, food, pharmaceutical, leather and textile industries and can be efficiently produced via several methods. Previously, succinic acid production via chemical synthesis from petrochemical or refined sugar has been the focus of interest of most reviewers. However, these expensive substrates have been recently replaced by alternative sustainable raw materials such as lignocellulosic biomass, which is cheap and abundantly available. Thus, this review focuses on succinic acid production utilizing lignocellulosic material as a potential substrate for SSF and SHF. SSF is an economical single-step process which can be a substitute for SHF — a two-step process where biomass is hydrolyzed in the first step and fermented in the second step. SSF of lignocellulosic biomass under optimum temperature and pH conditions results in the controlled release of sugar and simultaneous conversion into succinic acid by specific microorganisms, reducing reaction time and costs and increasing productivity. In addition, main process parameters which influence SHF and SSF processes such as batch and fed-batch fermentation conditions using different microbial strains are discussed in detail.     

Effect of electromagnetic fields of UHF range on dopamine-dependent behavior of rabbits

SHF radiation of low intensity does not influence on a stereotyped behaviour of rabbits induced by a dopamine receptor stimulator, apomorphine. However, 10% of animals exhibited a marked decrease in the test-response after SHF-irradiation (16 Hz) which was perhaps associated with the increased individual sensitivity of some animals to SHF-radiation.     

The effect of an SHF field on the dopamine-dependent behavior of rats

A study was made of the influence of SHF radiation (8 mW/cm2, carrier frequency 0.88 Hz, modulation frequency 16 Hz) on rotation of rats induced by apomorphine. A single exposure within an hour was shown to inhibit apomorphine-induced rotation by 21%. Daily one-hour exposure within 5 days caused a more pronounced inhibition of test-response. Different individual sensitivity to SHF radiation was noted.     

三种东亚冷杉植物的核型研究

首次报道了急尖长苞冷杉ＡｂｉｅｓｇｅｏｒｇｅｉＯｒｒｖａｒ．ｓｍｉｔｈｉｉ（ＶｉｇｕｉｅｅｔＧａｕｓｓｅｎ）Ｃｈｅｎｇｅｔ．Ｌ．Ｋ．Ｆｕ,臭冷杉Ａ．ｎｅｐｈｒｏｌｅｐｉｓ（Ｔｒａｕｒｖ．）Ｍａｘｉｍ和杉松,Ａ．ｈｏｌｏｐｈｙｌｌａｍａｘｉｍ等３种东亚冷杉植物的核型,它们的核型公式分别是Ｋ（２ｎ）＝２４＝１８ｍ（２ＳＣ）＋６ｓｍ,１８ｍ（６ＳＣ）＋６ｓｍ和１４ｍ（６ＳＣ）＋１０ｓｍ,染色体相对长度组     

Production of green biodegradable plastics of poly(3-hydroxybutyrate) from renewable resources of agricultural residues

This work describes potential opportunities for utilization of agro-industrial residues to produce green biodegradable plastics of poly(3-hydroxybutyrate) (PHB). Wheat straws were examined with good efficacy of carbon substrates using Cupriavidus necator. Production was examined in separate hydrolysis and fermentation (SHF) in the presence and absence of WS hydrolysis enzymes, and in simultaneous saccharification and fermentation (SSF) with enzymes. Results showed that production of PHB in SSF was more efficient in terms of viable cell count, cell dry weight, and PHB production and yield compared to those of SHF and glucose-control cultures. While glucose control experiment produced 4.6 g/L PHB; SSF produced 10.0 g/L compared to 7.1 g/L in SHF when utilizing enzymes during WS hydrolysis. Results showed that most of sugars produced during the hydrolysis were consumed in SHF (~98 %) compared to 89.2 % in SSF. Results also demonstrated that a combination of glucose and xylose can compensate for the excess carbon required for enhancing PHB production by C. necator. However, higher concentration of sugars at the beginning of fermentation in SHF can lead to cell inhibition and consequently catabolite repressions. Accordingly, results demonstrated that the gradual release of sugars in SSF enhanced PHB production. Moreover, the presence of sugars other than glucose and xylose can eliminate PHB degradation in medium of low carbon substrate concentrations in SSF.     

脊髓和周围神经可溶性酸性蛋白质的研究

 利用微型双向电泳、SDS电泳、免疫印迹法、DEAE-Sephadex色谱、高效液相色谱及氨基酸分析等方法,对牛脊髓(中枢神经)和马尾神经(周围神经)的可溶性酸性蛋白质进行了研究。结果表明在牛脊髓和马尾神经中有钙调素(CaM)、S-100蛋白和神经元特异烯醇化酶(NSE)等可溶性酸性蛋白质存在;脊髓中这些酸性蛋白质的含量远较马尾神经为高。     

The model of cupular dynamics in the case of the difference of the cupula and endolymph densities

The function of semicircular canals (SC) is based on the precise equality of densities of the cupula and endolymph. Otherwise the information provided by SC would depend on the orientation of both the gravity vector relative to canal plane and the axis of rotation. It would also depend on the distance between the axis of rotation and the center of the SC. We believe that the equality of densities is approximate and expect that due to the high sensitivity of the SC, even the small differences of densities (approximately 10(-4) g/cm3) can influence the SC dynamics, and this influence depends on the conditions of canal stimulation. The work aims to examine this hypothesis and analyze the parameters of the SC and mechanical stimulation under which the effect of the difference of densities on the SC functioning could be observed.     

Fine observation on nerves colonizing the regenerating tail of the lizard Podarcis sicula

During the regeneration of lizard tail, nerves sprouting from ganglia and the spinal cord invade the blastema as far as the apical epidermis. Electron microscopical observations reveal axons storing dense granules (dg) and dense core vesicles (dcv) which are concentrated in nerve terminals or in axoplasmatic regions. In the regenerating spinal cord (SC) these terminals resemble aminergic-peptidergic endings and grow as far as the distal portion of the SC, which is made up of irregularly arranged ependymal cells. Some axons storing dcv contact blastematic cells and other nerve terminals show a plasma membrane incomplete or broken. Whether this latter aspect is due to fixation artifacts or physiological rupture is unknown. Nerves containing dcv and a few dg also originate from spinal ganglia innervating the regenerating tail. The accumulation of material into these endings is probably slow and a possible trophic influence on the regeneration of lizard tail is discussed.     

Electrophysiologic study of cultured neurons dissociated from spinal cords and dorsal root ganglia of fetal mice

Spontaneously occurring action potentials and postsynaptic potentials were recorded intracellularly from mouse spinal cord (SC) neurons and dorsal root ganglion (DRG) neurons in mixed SC and DRG cell cultures. In some SC cells, excitatory postsynaptic potentials were evoked by electrical stimulation of a nearby SC or DRG cell. SC and DRG neurons had distinguishing morphologic and electrophysiologic properties. SC neurons usually were elliptical or stellate and had several branched processes whereas DRG cells were most commonly round and had on the average only one process, but occasionally 3 or 4. Calculations from cell measurements revealed that SC neurons had less soma surface area and more process surface area than DRG cells, with a similar total surface area for each class. Lower resting membrane potentials were recorded from SC neurons, but when the capability for action potential generation was tested at comparable steady membrane potentials, most SC and less than half of DRG neurons fired repetitively to electrical stimulation. During the depolarizing and repolarizing phases of SC cell action potentials the rates of change of membrane potential were lower than for DRG cells, which had rapidly rising action potentials and a markedly negative afterpotential. An initially delayed repolarization phase was characteristic of the DRG cell action potential. Cell cultures were prepared by trypsin dissociation of spinal cords with attached spinal ganglia from fetuses of 10, 11, 12, 13, 14, and 17 days gestational age. Cell cultures grown on plastic or collagen were studied electrophysiologically at times from 16 to 94 days.     

Spread of herpes simplex virus to the spinal cord is independent of spread to dorsal root ganglia

Levels of herpes simplex virus 1 (HSV-1) and HSV-2 DNA in dorsal root ganglia (DRG) and spinal cord (SC) were quantified after inoculation of guinea pig genitals and footpads. In genital infection, viral DNA reached SC and DRG simultaneously (at 2 to 3 days after inoculation) but was more abundant in SC than in DRG. After inoculation of footpads, which lack parasympathetic innervation, the viruses spread more efficiently to DRG than to SC. These results show important differences between genital and footpad infections, including independence of spread to DRG and SC, and imply that autonomic neurons may play an important role in the pathogenesis of viral latency after genital inoculation.     

Millimeter wave dosimetry of human skin

To identify the mechanisms of biological effects of mm waves it is important to develop accurate methods for evaluating absorption and penetration depth of mm waves in the epidermis and dermis. The main characteristics of mm wave skin dosimetry were calculated using a homogeneous unilayer model and two multilayer models of skin. These characteristics included reflection, power density (PD), penetration depth (delta), and specific absorption rate (SAR). The parameters of the models were found from fitting the models to the experimental data obtained from measurements of mm wave reflection from human skin. The forearm and palm data were used to model the skin with thin and thick stratum corneum (SC), respectively. The thin SC produced little influence on the interaction of mm waves with skin. On the contrary, the thick SC in the palm played the role of a matching layer and significantly reduced reflection. In addition, the palmar skin manifested a broad peak in reflection within the 83-277 GHz range. The viable epidermis plus dermis, containing a large amount of free water, greatly attenuated mm wave energy. Therefore, the deeper fat layer had little effect on the PD and SAR profiles. We observed the appearance of a moderate SAR peak in the therapeutic frequency range (42-62 GHz) within the skin at a depth of 0.3-0.4 mm. Millimeter waves penetrate into the human skin deep enough (delta = 0.65 mm at 42 GHz) to affect most skin structures located in the epidermis and dermis.     

3种北美冷杉的核型研究

本文首次报道３种北美冷杉Ａｂｉｅｓ ａｍａｂｉｌｉｓ、Ａ．ｇｒａｎｄｉｓ和Ａ．ｌａｓｉｏｃａｒｐａ的根尖体细胞核型、染色体参数及核型模式图。核型公式分别是Ｋ（２ｎ）＝２４＝１６ｍ（４ＳＣ）＋８ｓｍ、１４ｍ（２ＳＣ）＋１０ｓｍ和１８ｍ（４ＳＣ）＋６ｓｍ,染色体相对长度组成为２ｎ＝２４＝２Ｌ＋１２Ｍ２＋６Ｍ１＋４Ｓ、２Ｌ＋１２Ｍ２＋８Ｍ１＋２Ｓ和２Ｌ＋８Ｍ２＋１２Ｍ１＋２Ｓ。均为２Ａ核型类型。文中还讨     

Ablation of the secondary heart field leads to tetralogy of Fallot and pulmonary atresia

Recent studies in chick and mouse embryos have identified a previously unrecognized secondary heart field (SHF), located in the ventral midline splanchnic mesenchyme, which provides additional myocardial cells to the outflow tract as the heart tube lengthens during cardiac looping. In order to further delineate the contribution of this secondary myocardium to outflow development, we labeled the right SHF of Hamburger-Hamilton (HH) stage 14 chick embryos via microinjection of DiI/rhodamine and followed the fluorescently labeled cells over a 96-h time period. These experiments confirmed the movement of the SHF into the outflow and its spiraling migration distally, with the right side of the SHF contributing to the left side of the outflow. In contrast, when the right SHF was labeled at HH18, the fluorescence was limited to the caudal wall of the lengthening aortic sac. We then injected a combination of DiI and neutral red dye, and ablated the SHF in HH14 or 18 chick embryos. Embryos were allowed to develop until day 9, and harvested for assessment of outflow alignment. Of the embryos ablated at HH14, 76% demonstrated cardiac defects including overriding aorta and pulmonary atresia, while none of the sham-operated controls were affected. In addition, the more severely affected embryos demonstrated coronary artery anomalies. The embryos ablated at HH18 also manifested coronary artery anomalies but maintained normal outflow alignment. Therefore, the myocardium added to the outflow by the SHF at earlier stages is required for the elongation and appropriate alignment of the outflow tract. However, at later stages, the SHF contributes to the smooth muscle component of the outflow vessels above the pulmonary and aortic valves which is important for the development of the coronary artery stems. This work suggests a role for the SHF in a subset of congenital heart defects that have overriding aorta and coronary artery anomalies, such as tetralogy of Fallot and double outlet right ventricle.     

沙冬青属的细胞学研究

沙冬青属(Ammopiptanthus)植物仅两个种,即蒙古沙冬青(A.mongolicus)和新疆沙冬青(A.nanus),为第三纪残遗种,是中亚荒漠唯一的常绿阔叶植物,因珍稀,临危而被列为国家重点保护植物”。国内外对该属两个种的染色体数目的记载存在着差异。本文对沙冬青属两种植物的染色体数目和核型进行了分析研究,旨在为探讨该属植物的发生和系统发育,以及开展植物多样性保护和合理开发利用积累资料。     

Effects of stretch on work from fast and slow muscles of mice: damped and undamped energy release

Stretching active muscle increases the work performed during subsequent shortening. The effects of a preceding stretch on work done by the undamped or lightly damped series compliance (SC) and by the contractile component (CC), which includes cross bridges and damped elements, were assessed using mouse soleus (slow) and extensor digitorum longus (fast) muscles with limited tendon. Increasing stretch amplitude (0-10% fibre length) increased work done by the SC up to a limit, but did not effect work done by the CC. Increasing stretch velocity (10-100% Vmax) had almost no effect on work done by either component. Increasing the delay between the end of stretch and onset of shortening (0-60 ms) caused a decrease in SC work, with no effect on CC work. Recoil of the SC was responsible for 50-70% of the total work done during shortening after stretch. Usually only 10-40% of the energy imparted during the stretch was recovered as work during subsequent shortening; large stretches and long delays between stretch and shortening further reduced this recovery by one third to one fifth. Results are interpreted in the context of a loss of energy stored in the SC owing to forcible detachment of cross bridges with large stretches and cyclic detachment with long delays.