A comparative study of the anatomy of rat and human livers.
ABSTRACT To compare the fundamental structure of the human liver, in relation to that of the rat a comparative study was performed, in which 20 rat livers and 78 human cadaver livers were examined. The rat livers had four lobes (left, middle, right, and caudate). The left and middle lobes formed a single lobe but the middle lobe had a deep notch to which the round ligament attached. The right lobe was split into two sub-lobes and the caudate lobe was divided into the paracaval portion and the Spiegel lobe, which was split into two sub-lobes. The left, right, and caudate lobes had one primary portal branch, whereas the middle lobe had two portal branches. The left and the right sub- and caudate lobes had one large hepatic vein each, whereas three large hepatic veins were observed in the middle lobe. Based on the ramifying patterns of the portal and hepatic veins, the rat middle lobe possessed left and right hepatic components and a main portal fissure. The following rat hepatic lobes were equivalent to the following human liver segments: the left lobe to segment II; the middle lobe to segments III, IV, V, and VIII; and the right lobe to segments VI and VII. The fundamental structures of rat and human livers were similar, and the findings demonstrated a new interpretation of the anatomy of the human liver.
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ABSTRACT: The development of microsurgery has been dependent on experimental animals. Microsurgery could be a very valuable technique to improve experimental models of liver diseases. Microdissection and microsutures are the two main microsurgical techniques that can be considered for classifying the experimental models developed for liver research in the rat. Partial portal vein ligation, extrahepatic cholestasis and hepatectomies are all models based on microdissection. On the other hand, in portacaval shunts, orthotopic liver transplantation and partial heterotopic liver transplantation, the microsuture techniques stand out. By reducing surgical complications, these microsurgical techniques allow for improving the resulting experimental models. If good experimental models for liver research are successfully developed, the results obtained from their study might be particularly useful in patients with liver disease. Therefore experimental liver microsurgery could be an invaluable way to translate laboratory data on liver research into new clinical diagnostic and therapeutic strategies.World journal of hepatology. 07/2012; 4(7):199-208.
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ABSTRACT: PURPOSE: Repeated hepatic resections are not uncommon during the surgical management of liver tumors. Postoperative adhesions induced by hepatectomies can have a significant negative impact on subsequent surgeries. We recently developed a new hepatectomy-induced postoperative adhesion animal model to evaluate the anti-adhesion efficacy of commercially available sheet materials (Seprafilm(®) and Interceed(®)) and the recently reported hyaluronan-based in situ cross-linkable hydrogels. METHODS: The median lobe (ML) and the left lateral lobe (LLL) of the liver (approximately 70 % of the total liver) of 43 male Sprague-Dawley rats were resected based on the classical procedure; anti-adhesion materials were then applied. A relaparotomy was performed 1 week later to evaluate the adhesions and histopathological findings. RESULTS: The rats without the application of anti-adhesion materials (n = 14) showed the most severe adhesions (grade 3) between the cut surface of the liver and the small bowel or omentum. All the barrier materials produced slight anti-adhesion effects. Adhesions between the liver surface and the diaphragm and adhesions around the hepatic hilum were less severe, but were not remarkably reduced, by the anti-adhesion materials. CONCLUSION: We successfully established a new hepatectomy-induced animal adhesion model, which may be useful for the development of new anti-adhesion materials.Surgery Today 03/2013; · 0.96 Impact Factor
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ABSTRACT: Ultrasound Nakagami parametric imaging is a useful tool for tissue characterization. Previous literature has suggested using a square with side lengths corresponding to 3 times the transducer pulse length as the minimum window for constructing the Nakagami image. This criterion does not produce sufficiently smooth images for the Nakagami image to characterize homogeneous tissues. To improve image smoothness, we proposed window-modulated compounding (WMC) Nakagami imaging based on summing and averaging the Nakagami images formed using sliding windows with varying window side lengths from 1 to N times the transducer pulse length in 1 pulse length step. Simulations (the number densities of scatterers: 2-16 scatterers/mm(2)) and experiments on fully developed speckle phantoms (the scatterer diameters: 20-106μm) were conducted to suggest an appropriate number of frames N and to evaluate the image smoothness and resolution by analyzing the full width at half maximum (FWHM) of the parameter distribution and the widths of the image autocorrelation function (ACF), respectively. In vivo ultrasound measurements on rat livers without and with cirrhosis were performed to validate the practical performance of the WMC Nakagami image in tissue characterization. The simulation results showed that using a range of N from 7 to 10 as the number of frames for image compounding reduces the estimation error to less than 5%. Based on this criterion, the Nakagami parameter obtained from the WMC Nakagami image increased from 0.45 to 0.95 after increasing the number densities of scatterers from 2 to 16 scatterers/mm(2). The FWHM of the parameter distribution (bins=40) was 13.5±1.4 for the Nakagami image and 9.1±1.43 for the WMC Nakagami image, respectively (p-value<.05). The widths of the ACF for the Nakagami and WMC Nakagami images were 454±5.36 and 458±4.33, respectively (p-value>.05). In the phantom experiments, we also found that the FWHM of the parameter distribution for the WMC Nakagami image was smaller than that of the conventional Nakagami image (p-value<.05), and there was no significant difference of the ACF width between the Nakagami and WMC Nakagami images (p-value>.05). In the animal experiments, the Nakagami parameters obtained from the WMC Nakagami image for normal and cirrhotic rat livers were 0.62±0.08 and 0.92±0.07, respectively (p-value<.05). The results demonstrated that the WMC technique significantly improved the image smoothness of Nakagami imaging without resolution degradation, giving Nakagami model-based imaging the ability to visualize scatterer properties with enhanced image quality.Ultrasonics 08/2014; 54(6):1448–1459. · 2.03 Impact Factor