四川西部藏区包虫病流行病学研究Ⅱ.牲畜及野生动物两型包虫病感染状况调查

目的　明确四川西部地区石渠县、甘孜县牲畜和野生动物两型包虫病 (Hydatidosis,HD)的感染状况 ,为进一步开展防治工作做好基线调查。方法　采取捕杀、剖检、作病理切片等。结果　检查牦牛 42 9头 ,其中 2 19头感染细粒棘球蚴 (Cysticechinococcus,Ce)感染率为 5 0 8% ,3头感染多房棘球蚴 (Alveolarechinococcus,Ae)感染率为 0 7%。在啮齿类动物中 ,黑唇鼠兔 (Ochotonacurzoniae)Ae感染率为 5 6 % (13/2 33) ,灰尾兔 (Lepusoiostolus)Ae感染率为 7 1% (1/14) ,松田鼠 (PitymysireneThomas)Ae感染率为 2 5 % (3/12 ) 检查小家鼠 (Musmusculus) 70只未发现感染。终末宿主调查中 ,犬体内发现两种棘球绦虫感染 ,其中细粒棘球绦虫 (Echinococcusgranulosus,Eg)感染率为 13 2 % (7/16 ) ;多房棘球绦虫(Echinococcusmultilocularis,Em)感染率 16 98% (9/16 ) ,未发现混合感染犬。藏狐 (Vulpesferrilata)的Em感染率为 44 4%(76 /171)。结论　调查显示在该地区存在着较广泛的动物两型包虫病流行     

Spatial Learning Deficits in Adult Rats Exposed to ortho-Substituted PCB Congeners during Gestation and Lactation

Spatial learning and memory was assessed in rats following gestationaland lactational exposure to specific ortho-substituted PCBs.Time-mated Sprague-Dawley rats were exposed to PCB 28 (2,4,4'-trichlorobiphenyl),8 or 32 mg/kg/day, PCB 118 (2,3',4,4',5-pentachlorobiphenyl),4 or 16 mg/kg/day, PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl),16 or 64 mg/kg/day, or corn oil vehicle via gavage on GestationDays 10–16. Litters were culled to eight on Day 2 andweaned on Day 21. Beginning on Day 90, one male and one femalefrom each litter were tested on a working/reference memory taskon an eight-arm maze. For each rat, the same four arms werebaited throughout training. Animals were tested Monday-Friday,for seven consecutive weeks. No differences in working or referencememory errors were observed. The same animals were later testedon a T-maze delayed spatial alternation task. On each trial,the reinforcer was placed in the arm opposite that chosen bythe rat on the previous trial. Intertrial delays of 15, 25,or 40 sec appeared in counterbalanced order. Rats were testedMonday-Friday for three consecutive weeks. The higher dosesof all three congeners resulted in slower acquisition by femalerats. Males were not affected. PCB-exposed females were impairedat all delays and were not differentially more impaired at longerdelays, suggesting a learning or attentional deficit, ratherthan a mnemonic deficit. These findings demonstrate that perinatalexposure to ortho-substituted PCBs can result in long-lastingdeficits in learning and suggest that the effects of PCBs onlearning may be sex specific.     

Coexistence of slow and fast isoforms of contractile and regulatory proteins in human skeletal muscle fibres induced by endurance raining

The distribution of fast and slow isoforms of troponin C, I, and T components and myosin heavy chains was investigated in histochemically typed myofibrillar ATPase intermediate (IM) fibres, that is, fibres that stain after both acid and alkaline pre-incubation in stainings for myofibrillar ATPase. In addition to the previously described IM fibres of types II C and I B, fibres that displayed staining characteristics between types II C and I B were observed and termed type II C–I B. The IM fibres constitute less than 1% of the fibres in normal human limb and abdominal muscles. The IM fibres studied here resulted from extensive endurance training of human triceps brachii muscle (n= 6) and were induced by conversion of a proportion (130) of type II fibres. The immunohistochemical stains of serial sections with antibodies to slow isoforms of troponin I, T, C and myosin heavy chain showed no staining of type II fibres but intense staining of types I and I B fibres, whereas type II C fibres stained with intermediate intensity. The antibodies to fast isoforms of the troponin components and myosin heavy chain did not give rise to staining of type I fibres but dark staining of type II fibres. Type I B fibres stained with intermediate intensity and type II C was either as dark as type II or slightly lighter. Type II C-I B fibres showed staining intensities intermediate between those observed for types I B and IIC in the immunohistochemical stains. It is therefore concluded that training-induced myofibrillar ATPase intermediate human skeletal muscle fibres are characterized by the coexistence of slow and fast isoforms of contractile and regulatory proteins. Changes in the distribution of fast and slow isoforms of several of the myofibrillar proteins appeared to be induced in a co-ordinated manner.