The caudate processus hepatic vein: a boundary hepatic vein between the caudate lobe and the right liver.

OBJECTIVE: This study was conducted to find the boundary vein indicating the intersegmental plane between the caudate lobe and the adjacent liver segments. SUMMARY BACKGROUND DATA: Major hepatic veins of the human liver commonly run through the intersegmental plane and are widely used for the landmarks to define the boundary of both sides of liver segments. As the caudate lobe is a small independent unit of the liver separate from the right and left livers, the existence of the boundary hepatic vein to the adjacent liver segments has been expected. METHODS: Fifty-four adult cadaveric livers were minutely dissected to elucidate the correlation between the portal vein branches and the hepatic veins on both the caudate lobe and the adjacent liver segments. RESULTS: Among the hepatic veins of the caudate lobe, the caudate processus hepatic vein entering the inferior vena cava at hepatic hilum runs in the segmental plane between the caudate processus and the right liver. Three types of the caudate processus hepatic vein directly entering the inferior vena cava and 1 type of the exceptional hepatic vein that was the tributary of the right hepatic vein were observed. They drained the blood of the caudate processus and a part of the right liver, respectively. CONCLUSIONS: The caudate processus hepatic vein is one of the candidates of the hepatic vein indicating the boundary between the caudate lobe and the adjacent liver segments. New procedures will be developed on the liver surgeries by acquiring the anatomic features of this vein.

Close relation between the inferior vena cava ligament and the caudate lobe in the human liver.

BACKGROUND/PURPOSE: This study was conducted to clarify the real relation between the inferior vena cava (IVC) ligament and the caudate lobe in the human liver and also to elucidate their surgical importance in liver surgery. METHODS: Specimens obtained from 20 adult cadaveric livers were submitted for the study. Histological structures of the IVC ligament and its relationship to the caudate lobe and the IVC were microscopically investigated. RESULTS: The IVC ligament was a broad membranous connective tissue bridging the left and right side edges of the caval groove in which the IVC was embedded. At both edges of the caval groove, the IVC ligament was continuously transformed from the Glisson's capsules of the caudate and right lobes. The component of the portal triad, which originated from that of caudate lobe, and lymphatics were distributed in the IVC ligament without exception and ectopic hepatocytes existed in it in 4 of the 20 cases. CONCLUSIONS: A close relation between the IVC ligament and the caudate lobe was confirmed. The findings suggested that the IVC ligament is a kind of degenerated hepatic tissue. When dissecting it, surgeons should manipulate it carefully to prevent unexpected bleeding and bile leakage.

Zebrafish protocadherin 10 is involved in paraxial mesoderm development and somitogenesis.

Here, we present the first report of the molecular cloning of zebrafish protocadherin 10 (Pcdh10, OL-protocadherin) and describe its functional analyses in the development of segmental plate. Epitope-tagged Pcdh10 expressed in embryos was localized on cell peripheries of adjacent cells. In situ hybridization showed that pcdh10 was expressed in the paraxial mesoderm (PAM) and developing somites, and in the pineal body, the diencephalon, and the vicinity of otocysts. Expression in PAM increased in the last few presumptive somites, reached the maximum level in the latest segmenting somites, and decreased thereafter during somite maturation. These expression patterns suggested that Pcdh10 is involved in development of PAM and somites. This was confirmed by morpholino knockdown and dominant-negative inhibition of Pcdh10 in embryos, which disturbed movements of PAM cells and somite segmentation. Comparative studies showed that pcdh10 expression lasted up to approximately three times longer in maturing somites than that of paraxial protocadherin (pcdh8). They also indicated that the adaxial cells expressed pcdh8 but not pcdh10. We propose that Pcdh10 is involved in the morphogenic movements of PAM cells and somite segmentation and that differential adhesion of Pcdh8 and Pcdh10 plays a role in the morphogenic machinery of somites and adaxial cells.

Morphogenesis of an anomalous ligamentum venosum terminating in the superior left hepatic vein in a human liver.

BACKGROUND/PURPOSE: We aimed to clarify the morphogenesis of an anomalous ligamentum venosum terminating in the trunk of the superior left hepatic vein, because the ligamentum venosum ordinarily terminates into the root of the left hepatic vein or directly into the inferior vena cava. METHODS: We examined an anomalous ligamentum venosum found in the cadaveric liver of an 84-year-old Japanese woman. RESULTS: The ligamentum venosum in this liver was not found in the usual course, the fissure for the ligamentum venosum. It lay on the posterior surface of the liver, connecting the left branch of the portal vein and the trunk of a small left hepatic vein. The small left hepatic vein draining the cranio-dorsal part of the lateral segment of the liver was revealed to be a superior left hepatic vein. This type of anomaly was found only in this 1 liver, among 125 cadaveric livers that were dissected. CONCLUSIONS: Taking previous reports into consideration, the morphogenesis of the anomalous ligamentum venosum in the present case may be explained as being due to the persistence of the right half of the subdiaphragmatic anastomosis, which receives the blood from the ductus venosus in the embryonal period.

Clusters of VIP-36-positive vesicles between endoplasmic reticulum and Golgi apparatus in GH3 cells.

The vesicular integral membrane protein VIP36 belongs to the family of animal lectins and may act as a cargo receptor trafficking certain glycoproteins in the secretory pathway. Immunoelectron microscopy of GH3 cells provided evidence that endogenous VIP36 is localized mainly in 70-100-nm-diameter uncoated transport vesicles between the exit site on the ER and the neighboring cis-Golgi cisterna. The thyrotrophin-releasing hormone (TRH) stimulation and treatment with actin filament-perturbing agents, cytochalasin D or B or latrunculin-B, caused marked aggregation of the VIP36-positive vesicles and the appearance of a VIP36-positive clustering structure located near the cis-Golgi cisterna. The size of this structure, which comprised conspicuous clusters of VIP36, depended on the TRH concentration. Confocal laser scanning microscopy confirmed the electron microscopically demonstrated distribution and redistribution of VIP36 in these cells. Furthermore, VIP36 colocalized with filamentous actin in the paranuclear Golgi area and its vicinity. This is the first study to show the ultrastructural distribution of VIP36 in the early secretory pathway in GH3 cells. It suggests that actin filaments are involved in glycoprotein transport between the ER and cis-Golgi cisterna by using the lectin VIP36.

Localization of VIP36 in the post-Golgi secretory pathway also of rat parotid acinar cells.

VIP36 (36-kD vesicular integral membrane protein), originally purified from Madin-Darby canine kidney (MDCK) epithelial cells, belongs to a family of animal lectins and may act as a cargo receptor. To understand its role in secretory processes, we performed morphological analysis of the rat parotid gland. Immunoelectron microscopy provided evidence that endogenous VIP36 is localized in the trans-Golgi network, on immature granules, and on mature secretory granules in acinar cells. Double-staining immunofluorescence experiments confirmed that VIP36 and amylase co-localized in the apical regions of the acinar cells. This is the first study to demonstrate that endogenous VIP36 is involved in the post-Golgi secretory pathway, suggesting that VIP36 plays a role in trafficking and sorting of secretory and/or membrane proteins during granule formation.

Plectin tethers desmin intermediate filaments onto subsarcolemmal dense plaques containing dystrophin and vinculin.

Plectin is a versatile cytoskeletal linker protein that preferentially localizes at interfaces between intermediate filaments and the plasma membrane in muscle, epithelial cells, and other tissues. Its deficiency causes muscular dystrophy with epidermolysis bullosa simplex. To better understand the functional roles of plectin beneath the sarcolemma of skeletal muscles and to gain some insights into the underlying mechanism of plectin-deficient muscular dystrophy, we studied in vivo structural and molecular relationships of plectin to subsarcolemmal cytoskeletal components, such as desmin, dystrophin, and vinculin, in rat skeletal muscles. Immunogold electron microscopy revealed that plectin fine threads tethered desmin intermediate filaments onto subsarcolemmal dense plaques overlying Z-lines and I-bands. These dense plaques were found to contain dystrophin and vinculin, and thus may be the structural basis of costameres. The in vivo association of plectin with desmin, (meta-)vinculin, dystrophin, and actin was demonstrated by immunoprecipitation experiments. Treatment of plectin immunoprecipitates with gelsolin reduced actin, dystrophin, and (meta-)vinculin but not desmin, implicating that subsarcolemmal actin could partly mediate the interaction between plectin and dystrophin or (meta-)vinculin. Altogether, our data suggest that plectin, along with desmin intermediate filaments, might serve a vital structural role in the stabilization of the subsarcolemmal cytoskeleton.

Reproposal for Hjortsjo's segmental anatomy on the anterior segment in human liver.

BACKGROUND: A minimum, but necessary amount, of cancer-containing liver tissue is to be excised in patients who have poor liver function. To achieve that goal of excision, a limited hepatic resection has been carried out. However, performing subsegmentectomy of the anterior segment according to the conventional segmental anatomy introduced by Healey and Schroy or Couinaud is difficult. Because the transverse border between segments 5 and 8 was drawn as an imaginary line through the right portal vein, there is no anatomical structure indicating this border. HYPOTHESIS: Hjortsjo divided the anterior segment into 2 vertical segments according to the fissure in which a hepatic vein coursed. By including Hjortsjo's concept of segmental anatomy, new procedures will be added to hepatic surgery. DESIGN: Sixty-five cadaveric livers were dissected to confirm Hjortsjo's concept of segmental anatomy by investigating the vertical fissure that divides the anterior segment into 2 areas, concerning the relation between portal segmentation and the hepatic venous system of the anterior segment. RESULTS: The territories of the third-order portal branches of the anterior segment were divided into 2 (ventral and dorsal) areas with a vertical fissure and in its intersubsegmental plane, an independent hepatic vein, or a first-order branch of the middle or the right hepatic vein coursed. CONCLUSIONS: These findings confirmed the certainty of Hjortsjo's concept of segmental anatomy of the anterior segment. This is relevant for developing new procedures in hepatic surgery. Its reproposal is opportune for adding it as another concept to the conventional segmental anatomy.