Parenteral and enteral metabolism of anaplerotic triheptanoin in normal rats

A new chronic treatment for inherited disorders of long-chain fatty acid oxidation involves administering up to one-third of dietary calories as triheptanoin, a medium-odd-chain triglyceride (Roe CR, Sweetman L, Roe DS, David F, and Brunengraber H. J Clin Invest 110: 259-269, 2002). Heptanoate and C(5)-ketone bodies derived from its partial oxidation in liver are precursors of anaplerotic propionyl-CoA in peripheral tissues. It was hypothesized that increasing anaplerosis in peripheral tissues would boost energy production. In the present study, we tested the potential of a triheptanoin emulsion as an intravenous nutrient. Normal rats were infused with triheptanoin intravenously or intraduodenally at up to 40% of caloric requirement. The blood concentration ratio (heptanoate/C(5)-ketone bodies) was high with intravenous and low with intraduodenal triheptanoin infusion. During intravenous infusion of triheptanoin, lipolysis was stimulated but appeared compensated by fatty acid reesterification. During intraduodenal infusion of triheptanoin, lipolysis was not stimulated. Our data support the hypothesis that intravenous triheptanoin could be used to treat decompensated patients with long-chain fatty acid oxidation disorders.     

流感病毒的检测和分型技术研究进展

近年来,病毒性流感的不断流行和暴发已引起世界范围的广泛关注。为了更好地对流感病毒进行检测和分型,我们对目前流感病毒常用的血清学检测和分型方法、免疫荧光法、PCR方法、多重RT-PCR法、实时RT-PCR法、依赖核酸序列的扩增法、环介导等温扩增法、焦磷酸测序法、基因芯片技术分别进行了描述,并阐述了其优缺点。     

Comparison of gross visual and microscopic assessment of four anatomic sites to monitor Besnoitia tarandi in barren-ground caribou (Rangifer tarandus)

The objective of this study was to establish a standardized protocol to monitor Besnoitia tarandi prevalence and intensity in barren-ground caribou (Rangifer tarandus) herds by: 1) calculating the relative sensitivity and specificity of the gross visual assessment of four anatomical sites compared with microscopic evaluation, and 2) determining which of four anatomical sampling sites was the most sensitive for detecting B. tarandi cysts by microscopy. Sampled tissues consisted of the conjunctiva of the left eye and skin sections from the rostrum, metatarsus, and thigh from 312 harvested caribou. Diagnosis of infection with B. tarandi was based on observation of at least one cyst by microscopic examination. For each tissue, the maximal density of cysts (number of B. tarandi cysts/mm(2) in the section examined) was calculated for a measured area consisting of the dermis extending from the epidermis of the skin to the base of the hair follicles and adnexal structures. For the conjunctiva, the entire submucosa was evaluated. Gross visual evaluation markedly underestimated B. tarandi prevalence in caribou with a relative sensitivity ranging from 0.29 in the conjunctiva to 0.13 in the skin section from the thigh, whereas relative specificities ranged from 0.98 to 1.00. The metatarsus and rostrum skin sections had the highest probabilities of cyst detection of all four anatomical sampling sites. The metatarsus harbored significantly higher densities of B. tarandi cysts than the rostrum, thigh, or conjunctiva. In conclusion, microscopic evaluation of a skin section from the anterior aspect of the mid-third portion of the metatarsal region could be used as a standardized comparative indicator of density of B. tarandi infection in Rangifer.     

Video microsurgery: evaluation of standard laparoscopic equipment for the practice of microsurgery

Traditional microsurgery involves the use of bulky and expensive stereo microscopes that have limited portability. Recent advances in video technology have enabled the exploration of alternative visualization methods. The purpose of this study was to evaluate standard laparoscopic equipment for microvascular anastomoses. Eight surgeons completed anastomoses on rat femoral and synthetic vessels using stereo microsurgery and video microsurgery visualization systems. All surgeons had previous experience with stereo microsurgery and none had ever used video microsurgery. Data were collected on overall anastomosis and individual suture times. A sample of completed anastomoses was placed in a video database and evaluated by use of a quality rating scale (8 to 10, excellent; 6 to 7, adequate; less than 6, poor). All surgeons subjectively evaluated the video microsurgery system. A total of 48 anastomoses were completed. The average total anastomosis time for the stereo microsurgery was 1018.9 +/- 463.2 seconds versus 1738.9 +/- 460.1 seconds for the video microsurgery. The average individual suture placement time was 114.6 +/- 60.6 seconds for the stereo microsurgery versus 211.7 +/- 128.4 seconds for the video microsurgery (p < 0.05). Twenty-five of the anastomoses underwent quality review. The overall score of the stereo microsurgery group was 8.1 +/- 1.7, and the video microsurgery group had an overall score of 7.3 +/- 1.6. Survey results revealed that 75 percent of the participants thought that the video microsurgery would be useful for human operations and would improve surgeon comfort, but 87.5 percent would not use the present video microsurgery system over stereo microsurgery in their practice. Although significant differences exist in overall anastomosis and individual suture completion times, no difference was found in the overall quality. Video microsurgery could become a useful tool on the basis of surgeon ergonomics; however, optical parameters require further refinement.     

Global warming is changing the dynamics of Arctic host-parasite systems

Global climate change is altering the ecology of infectious agents and driving the emergence of disease in people, domestic animals, and wildlife. We present a novel, empirically based, predictive model for the impact of climate warming on development rates and availability of an important parasitic nematode of muskoxen in the Canadian Arctic, a region that is particularly vulnerable to climate change. Using this model, we show that warming in the Arctic may have already radically altered the transmission dynamics of this parasite, escalating infection pressure for muskoxen, and that this trend is expected to continue. This work establishes a foundation for understanding responses to climate change of other host-parasite systems, in the Arctic and globally.     

Caudal polymorphism and cephalic morphology among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae: Elaphostrongylinae) in Dall's sheep from the Mackenzie Mountains, Canada

We demonstrate polymorphism in the structure of the tail among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae). Two distinct larvae, both with a characteristic dorsal spine, include (1) a morphotype with a kinked conical tail marked by 3 distinct transverse folds or joints and a symmetrical terminal tail spike and (2) a morphotype with a digitate terminal region lacking folds or joints and with an asymmetrical, subterminal tail spike. These divergent larval forms had been postulated as perhaps representing distinct species of elaphostrongyline nematodes. Application of a multilocus approach using ITS-2 sequences from the nuclear genome and COX-II sequences from the mitochondrial genome confirmed the identity of these larvae as P. odocoilei. Additionally, based on scanning electron microscopy (low-temperature field emission), the cephalic region of these larvae consisted of a cuticular triradiate stoma surrounded by 6 single circumoral papillae of the inner circle, 10 papillae of the outer circle (4 paired and 2 single), and 2 lateral amphids. Our's is the first demonstration of structural polymorphism among larval conspecifics in the Metastrongyloidea and Strongylida. The basis for this polymorphism remains undetermined, but such phenomena, if discovered to be more widespread, may contribute to continued confusion in discriminating among first-stage larvae for species, genera, and subfamilies within Protostrongylidae.