厦门港区残存鼠群落结构的研究

目的 对厦门港区4种类型码头即集装箱码头，散货码头，煤码头和客运码头的残存鼠群落结构进行研究。以探索防制对策。方法 夹夜法。结果 集装箱码头和散货码头残存鼠群落结构相似。为自JuQing 褐家鼠 黄胸鼠；煤码头为臭JuQing 黄胸鼠 黄毛鼠；客运码头以臭JuQing为主。臭JuQing是港区的优势鼠种。结论 不同类型码头的残存鼠生物多样性指数各不相同。以集装箱码头最高。集装箱码头和散货码头鼠类群落间相似性指数最高。     

辽宁省家栖鼠种类组成与数量动态的研究

本文以1985～1991年城乡家栖鼠鼠情监测资料为主要依据,揭示了辽宁省城乡家栖鼠种类组成与数量的月变动及七年来年变动趋势。城乡1年内均有两个数量商峰,城市数量高峰为4～5月与9～10月,农村数量高峰为3～4月与10～11月。城市家鼠数量明显呈下降趋势,鼠密度被控制在1%以下;农村鼠密度也下降,但平均密度高于2%。     

绥芬河公路口岸附近地区鼠类EHF IgG抗体调查报告

目的 了解绥芬河公路口岸附近EHF亚在鼠类中的流行动态。方法 对鼠类进行EHF IgG抗体监测。结果 检测142只、5种鼠类的血样，检出EHF IgG抗体阳性29例，阳性率为20．42％。其中黑线姬鼠的移抗体IgG抗体阳性率较高，为30．95％。结论 EHF宿主是属于多源性动物宿主，而黑线姬鼠是主要贮存宿主和传染源，提示我们要注意防鼠、灭鼠。     

吉林省七年鼠情监测结果分析

吉林省经七年来的鼠情监测,基本查清与人们接触密切的鼠类,特别是传播疾病的主要鼠类的分布规律,分析出我省家鼠有两个高峰(6月和10～11月),野鼠也有两个高峰(6月和10月),这与我省流行性出血热两个高峰相吻合,鼠峰在病峰之前。1986年以后,由于我省开展大规模灭家鼠活动,家鼠高峰已不存在规律性。通过几年来的灭鼠活动,使家鼠密度呈下降趋势,城镇褐家鼠和小家鼠构成比发生变化。城镇未爆发家鼠型流行性出血热。鼠情监测为灭鼠防病工作提供了科学依据。     

溴敌隆灭动物园害鼠效果观察

用0.5%溴敌隆母液配制的0.005%毒饵,采用7天饱和投饵,取得了100%的灭效;0.025%敌鼠钠盐以同样方法投饵,灭效为93.33%。从而证实,溴敌隆是目前在灭鼠效力、适口性、安全性方面较好的抗凝血灭鼠剂之一。     

Granulocyte Colony-stimulating Factor Supports Liver Regeneration in a Small-for-size Liver Remnant Mouse Model

Experimental partial hepatectomy of more than 80% of the liver weight bears an increased mortality in rodents, due to impaired hepatic regeneration in small-for-size liver remnants. Granulocyte colony-stimulating factor (G-CSF) promotes progenitor cell expansion and mobilization and also has immunomodulatory properties. The aim of this study was to determine the effect of systemically administered G-CSF on liver regeneration and animal survival in a small-for-size liver remnant mouse model. Mice were preconditioned daily for 5 days with subcutaneous injections of 5 μg G-CSF or aqua ad injectabile. Subsequently, 83% partial hepatectomy was performed by resecting the median, the left, the caudate, and the right inferior hepatic lobes in all animals. Daily sham or G-CSF injection was continued. Survival was significantly better in G-CSF-treated animals (P < 0.0001). At 36 and 48 h after microsurgical hepatic resection, markers of hepatic proliferation (Ki67, BrdU) were elevated in G-CSF-treated mice compared to sham injected control animals (P < 0.0001) and dry liver weight was increased (P < 0.05). G-CSF conditioning might prove to be useful in patients with small-for-size liver remnants after extended hepatic resections due to primary or secondary liver tumors or in the setting of split liver transplantation. Presented at the Forty-seventh Annual Meeting of The Society for Surgery of the Alimentary Tract, Los Angeles, CA, May 14–19, 2006 (poster presentation).     

Subthreshold oscillations generated by TTX-sensitive sodium currents in dorsal cochlear nucleus pyramidal cells

During intracellular recordings in rodent brainstem slice preparations, dorsal cochlear nucleus (DCN) pyramidal cells (PCs) exhibit characteristic discharge patterns to depolarizing current injection that depend on the membrane potential from which the responses are evoked. When depolarized from hyperpolarized potentials, PCs can respond with a short-latency action potential followed by a long silent interval (pauser) or a train of action potentials with a long latency (buildup). During the silent intervals in a pauser or a buildup response, the membrane potential slowly depolarizes towards spike threshold, often exhibiting distinct voltage oscillations of 1–2 mV before the first spike. The subthreshold voltage oscillations were investigated using whole cell recordings from DCN PCs in rat pup (P10–14) brainstem slices. The oscillations were unaffected by excitatory and inhibitory neurotransmitter antagonists, and were not temporally locked to the onset of the depolarization. The oscillations typically became larger as spike threshold was approached, and had a characteristic frequency between 40 and 100 Hz. In the presence of tetrodotoxin (TTX, 500 nM), the oscillations were significantly suppressed, and could not be evoked at any voltage below or above spike threshold. The oscillations were not blocked by phenytoin or Cd²⁺, but they were affected by prior activity in the neuron for approximately 1 s. We conclude that voltage-gated Na⁺ channels are required to generate membrane oscillations during the buildup phase. We suggest that the subthreshold oscillations play a role in controlling spike timing in PCs when the membrane potential slowly approaches, or hovers near, spike threshold.     

Diet salinity and vasopressin as reproduction modulators in the desert-dwelling golden spiny mouse (Acomys russatus)

The time for reproduction in mammals largely depends on the availability of water and food in their habitat. Therefore, in regions where rains are limited to definite seasons of the year, mammals presumably will restrict their breeding correspondingly. But while mammals living in predictable ecosystems would benefit by timing their season to an ultimate predictable cue, such as photoperiod, in unpredictable ecosystems (e.g., deserts) they will need to use a more proximate signal. We suggest a mechanism by which water shortage (low water content in plants) could act as a proximate cue for ending the reproductive season. The golden spiny mouse (Acomys russatus), a diurnal rodent living in extreme deserts, may face an increased dietary salt content as the summer progresses and the vegetation becomes dry. Under laboratory conditions, increased diet salinity lead to reproductive hiatus in females, notable in imperforated vagina, and a significant decrease in the ovaries, uteri, and body masses. In females treated with vasopressin (VP), a hormone expressed during water stress, the uteri and body masses have decreased significantly, and the ovaries exhibited an increased number of atretic follicles. VP has also led to a significant decrease in relative medullary thickness (RMT) of the kidney. It is thus suggested that VP could act as a modulator linking the reproductive system with water economy in desert rodents, possibly through its act on the energetic pathways.     

Structural and replicative forms of mitochondrial DNA in tissues from adult and senescent BALB/c mice and Fischer 344 rats

Age-related changes in the structure and replication of mitochondrial DNA (mtDNA) were investigated in different organs from young adult (9–10 months' old) and senescent (28–29 months' old) BALB/c mice and Fischer 344 rats. Total mtDNA from brain, heart, kidney and liver was isolated by centrifugation in ethidium bromide—CsCl gradient and examined for the occurrence of complex forms and replicative intermediates by electron microscopy. The frequency of catenated mtDNA (interlinked molecules containing two or more circular units) varied from about 2.5% to 5% in adult tissues and showed a small increase in the majority of senescent organs. The frequency of double-sized circular molecules, or circular dimers, was very low in adult tissues, with an average of about 0.04% in mice and 0.1% in rats. The frequency of circular dimers increased with aging to 1.9% in mouse brain and 1.5% in rat kidney, with smaller increases (0.4% and 0.7%) in heart mtDNA from both species; there was no significant increase in the other organs. It is suggested that the increase in the frequency of circular dimer mtDNA reflects an overall deterioration of tissue physiology rather than intrinsic senescent changes in the mitochondria. The frequencies and types of the various replicative forms of mtDNA varied significantly according to tissue but not according to species or donor age. The only exception was a significant increase in the frequency of larger replicative forms in senescent mouse liver, to about 20% compared with 12% in adult liver, suggesting an age-related change in the rate of mtDNA replication and/or turnover in this organ.     

Long-term treatment with anti-alpha 4 integrin antibodies aggravates colitis in G alpha i2-deficient mice

Targeted deletion of the heterotrimeric G protein, Galphai2, in mice induces lethal colitis closely resembling ulcerative colitis. In chronic colitis, migration of circulating leukocytes into the intestinal mucosa is partially dependent on alpha4 integrins. In previous studies, short-term administration of anti-alpha4 integrin antibodies has been shown to attenuate intestinal inflammation, and here we elucidate the effect of long-term administration of anti-alpha4 integrin antibodies on colitis in Galphai2(-/- )mice. Long-term blockade of alpha4 integrin significantly increased the severity of colitis in Galphai2(-/-) mice. The inflammation was confined to the colon, associated with increased cancer in situ, destruction of crypt architecture, and increased production of IL-1beta, TNF-alpha and IFN-gamma. Blockade of alpha4 integrin reduced the recruitment of activated T cells to the small intestine. In strong contrast, there were significantly higher numbers of activated T cells in the colonic lamina propria and epithelium, most probably due to in situ proliferation. Furthermore, treatment with alpha4 integrin antibodies induced decreased levels of total IgA and IgG in sera, whereas total IgM levels were unchanged. These new findings may have implications in the understanding of the progression of chronic intestinal inflammation.