Estimation of the congestion area volume in potential living donor remnant livers

BACKGROUND

Living donor liver transplantation is widely performed in adult patients. One of the problems in this setting is a small-for-size graft, which results in dysfunction and poor prognosis of a transplantation. A right liver graft was devised to overcome this problem; furthermore, inclusion of the middle hepatic vein (MHV) has been suggested to greatly improve recipient outcomes. However, extended right hepatectomy involves a surgical risk for the living donor in terms of congestion of the left paramedian sector. The volume of the venoocclusive region of a living donor liver possibly varies depending on the collateral patterns of veins draining the cranial part of segment 4 (S4).

PATIENTS AND METHODS

We were analyzed the normal livers of 50 patients who underwent triphasic contrast-enhanced multidetector row computed tomography during preoperative and postoperative examinations. The patient pathologies consisted of gastric cancer (n = 25), colon cancer (n = 1), or renal cancer (n = 24). We calculated the volume of the entire liver as well as those of the right graft and left remnant lobes for comparison with the drainage volume of each hepatic vein and its branches.

RESULTS

On the basis of the anatomic venous drainage of the cranial part of S4 (V4sup), we classified hepatic veins as group A (n = 31), the V4sup joined the left hepatic vein or the MHV distal to the vein draining S8 area (MV8), or group B (n = 19), V4sup joined the MHV proximal to MV8. The mean volume of the congested area was 6.9% in group A and 15.9% in group B. The venoocclusive areas in the remnant livers were estimated to be larger in group B (P < .001).

CONCLUSION

The collateral pattern of V4sup and MV8 as well as preoperative volumetric analysis are important for graft selection to decide the line of transection.

[An approach to solving the problem of missing data: identifying and dealing with mechanisms adequately]

Being confronted with missing data, the most important step is the knowledge of the underlying mechanism. In consequence of this, modern missing data techniques in contrast to past techniques are presented and compared, which can deal with more common situations. Finally, concrete instructions for the correct treatment of missing data are given.

Hydrodynamic delivery of plasmid DNA encoding human FcγR-Ig dimers blocks immune-complex mediated inflammation in mice

Therapeutic use and function of recombinant molecules can be studied by the expression of foreign genes in mice. In this study, we have expressed human Fcgamma receptor –Ig fusion molecules (FcγR-Igs) in mice by administering FcγR-Ig plasmid DNAs hydrodynamically and compared their effectiveness to purified molecules in blocking immune-complex (IC) mediated inflammation in mice. The concentration of hydrodynamically expressed FcγR-Igs (CD16A^F-Ig, CD32A^R-Ig and CD32A^H-Ig) reached a maximum of 130 μg/ml of blood within 24 h after plasmid DNA administration. The in vivo half-life of FcγR-Igs was found to be 9-16 days and Western blot analysis showed that the FcγR-Igs were expressed as a homodimer. The hydrodynamically expressed FcγR-Igs blocked 50-80% of IC-mediated inflammation up to 3 days in a reverse passive Arthus reaction model. Comparative analysis with purified molecules showed that hydrodynamically expressed FcγR-Igs are more efficient than purified molecules in blocking IC-mediated inflammation and had a higher half-life. In summary, these results suggest that the administration of a plasmid vector with a FcγR-Ig gene can be used to study the consequences of blocking IC-binding to FcγRs during the development of inflammatory diseases. This approach may have potential therapeutic value in treating IC-mediated inflammatory autoimmune diseases such as lupus, arthritis and autoimmune vasculitis.

Pantothenate kinase-associated neurodegeneration in Korea: recurrent R440P mutation in PANK2 and outcome of deep brain stimulation

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the mutation status of PANK2 among Korean patients with pantothenate kinase-associated neurodegeneration (PKAN) and to document the outcome of pallidal deep brain stimulation (DBS).

METHODS

Direct sequencing and deletion/duplication analysis of PANK2 were conducted in 12 patients (11 unrelated) with PKAN, diagnosed on the basis of extrapyramidal dysfunction and the 'eye-of-the-tiger sign' on brain magnetic resonance imaging (MRI). Pallidal DBS was conducted in four patients, and the outcomes were measured using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS).

RESULTS

A PANK2 mutation was identified in both alleles in all patients. The most prevalent mutation was c.1319G>C (p.R440P) in 8/22 mutated alleles (36%). An intragenic deletion ranging from exons 2 to 4 was found in one allele (1/22, 4.5%) using deletion/duplication analysis. The outcome of pallidal DBS was favorable in two patients with atypical PKAN and moderate severity of dystonia. However, two patients with typical PKAN and relatively severe symptoms showed variable responses.

CONCLUSIONS

The c.1319G>C (p.R440P) mutation appears to be a founder genotype among Korean patients with PKAN. Furthermore, this study provides additional data for the recent international effort to evaluate the efficacy of pallidal DBS in the treatment of patients with PKAN.

Psidin, a conserved protein that regulates protrusion dynamics and cell migration

Dynamic assembly and disassembly of actin filaments is a major driving force for cell movements. Border cells in the Drosophila ovary provide a simple and genetically tractable model to study the mechanisms regulating cell migration. To identify new genes that regulate cell movement in vivo, we screened lethal mutations on chromosome 3R for defects in border cell migration and identified two alleles of the gene psidin (psid). In vitro, purified Psid protein bound F-actin and inhibited the interaction of tropomyosin with F-actin. In vivo, psid mutations exhibited genetic interactions with the genes encoding tropomyosin and cofilin. Border cells overexpressing Psid together with GFP-actin exhibited altered protrusion/retraction dynamics. Psid knockdown in cultured S2 cells reduced, and Psid overexpression enhanced, lamellipodial dynamics. Knockdown of the human homolog of Psid reduced the speed and directionality of migration in wounded MCF10A breast epithelial monolayers, whereas overexpression of the protein increased migration speed and altered protrusion dynamics in EGF-stimulated cells. These results indicate that Psid is an actin regulatory protein that plays a conserved role in protrusion dynamics and cell migration.

Laparoscopy-assisted hepatic lobectomy using hilar Glissonean pedicle transection

Although many reports have described laparoscopic minor liver resections, major hepatic resection, including right or left lobectomy, has not been widely developed because of technical difficulties. This article describes a new technique for performing laparoscopy-assisted right or left hepatic lobectomy using hilar Glissonean pedicle transection. Laparoscopic mobilization of the right or left hepatic lobe is performed, including dissection of the round, faliciform, triangular, and coronary ligaments. The right or left Glissonean pedicle is encircled and divided laparoscopically. A parenchymal dissection is then performed though the upper median or right subcostal incision, through which the resected liver is removed. We successfully performed this procedure in 6 patients without blood transfusion or serious complications. Laparoscopy-assisted hepatic lobectomy using hilar Glissonean pedicle transection can be feasible and safe in highly selected patients.

Optical coherence microscopy for the evaluation of a tissue-engineered artificial cornea

A transparent artificial cornea derived from biological material is the ultimate goal of corneal research. Attempts at artificial corneal constructs produced from synthetic polymers have proved unsuccessful due to lack of biocompatibility and ability to integrate into the tissue. We have designed a corneal model derived from collagenous biological materials that has several advantages: it has low antigenicity and therefore small chance of eliciting an immune reaction, it can be broken down by the body's own cells and gradually replaced over time by natural materials, and it may contain signaling information for native cells, thereby inducing normal phenotype and behavior. In addition, a transparent corneal model has the potential to be used for testing of novel ophthalmic drugs or gene therapy approaches, eliminating the need for animal testing. We have used an optical coherence microscope (OCM) to evaluate both the structure of our tissue constructs over time in culture and the optical properties of the tissue itself. This imaging technique promises to be an important diagnostic tool in our efforts to understand the influence of mechanical forces, cell phenotype, and soluble factors on the transparency of corneal tissue.

PLCgamma is enriched on poly-phosphoinositide-rich vesicles to control nuclear envelope assembly

Nuclear envelope assembly is an essential event in each cell cycle but the proteins and lipids involved in its regulation remain mostly unknown. Assembly involves membrane fusions but neither specific SNAREs nor Rab GTPases have been identified in its control. We report that a precursor membrane population (MV1) required for NE assembly has a unique lipid composition consisting prominently of poly-phosphatidylinositides. The lipid composition was determined by adapting HPLC electrospray ionisation tandem mass spectrometry to phosphoinositide analysis, revealing the capacity of this technique to document dynamic lipid transitions of functional importance in natural membrane populations. MV1 is >100-fold enriched in endogenous PLCgamma and >25-fold enriched in the PLC substrate phosphatidylinositol bisphosphate (PtdInsP2) compared to the second membrane population, derived largely from endoplasmic reticulum (ER), that contributes most of the NE. During NE formation PLCgamma becomes transiently phosphorylated at the tyrosine 783 site indicative of its activation. In addition specific inhibition of PLCgamma blocks nuclear envelope formation. In vivo, PLCgamma is concentrated on vesicles of similar size to purified MV1. These associate with nuclei during the period of NE formation and are distinct from ER membranes. The unprecedented concentration of PLCgamma and its substrate PtdInsP2 in a subset of membranes that binds to only two regions of the nucleus, and activation of PLCgamma by GTP during initial stages of NE formation provide a mechanism for temporal control of NE assembly and offer an explanation for how such a process of membrane fusion can be spatially regulated.