Axis formation is one of the most important events occurring at the beginning of animal development. In the ascidian egg, the antero-posterior axis is established at this time owing to a dynamic ...cytoplasmic movement called cytoplasmic and cortical reorganisation. During this movement, mitochondria, endoplasmic reticulum (ER), and maternal mRNAs (postplasmic/PEM RNAs) are translocated to the future posterior side. Although accumulating evidence indicates the crucial roles played by the asymmetrical localisation of these organelles and the translational regulation of postplasmic/PEM RNAs, the organisation of ER has not been described in sufficient detail to date owing to technical difficulties. In this study, we developed three different multiple staining protocols for visualising the ER in combination with mitochondria, microtubules, or mRNAs in whole-mount specimens. We defined the internally expanded “dense ER” using these protocols and described cisterna-like structures of the dense ER using focused ion beam-scanning electron microscopy. Most importantly, we described the dynamic changes in the colocalisation of postplasmic/PEM mRNAs and dense ER; for example,
macho-1
mRNA was detached and excluded from the dense ER during the second phase of ooplasmic movements. These detailed descriptions of the association between maternal mRNA and ER can provide clues for understanding the translational regulation mechanisms underlying axis determination during ascidian early embryogenesis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In many animal species, the body axis is determined by the relocalization of maternal determinants, organelles, or unique cell populations in a cytoskeleton-dependent manner. In the ascidian first ...cell cycle, the myoplasm, including mitochondria, endoplasmic reticulum (ER), and maternal mRNAs, move to the future posterior side concomitantly (called ooplasmic segregation or cytoplasmic and cortical reorganization). This translocation consists of first and second phases depending on the actin and microtubule, respectively. However, the transition from first to second phase, that is, translocation of myoplasmic components from microfilaments to microtubules, has been poorly investigated. In this study, we analyzed the relationship between these cytoskeletons and myoplasmic components during the first cell cycle and their role in morphogenesis by inhibitor experiments. Owing to our improved visualization techniques, there was unexpected F-actin accumulation at the vegetal pole during this transition period. When this F-actin was depolymerized, the microtubule structure was strongly affected, the myoplasmic components, including maternal mRNA, were mislocalized, and the anteroposterior axis formation was disordered. These results suggested the importance of F-actin during the first cell cycle and the existence of interactions between microfilaments and microtubules, implying the enigmatic mechanism of ooplasmic segregation. Solving this mystery leads us to an improved understanding of ascidian early development.
Treatment of empyema after pneumonectomy is challenging. We treated 4 patients with postpneumonectomy empyema using a free rectus abdominis myocutaneous flap together with a pedicled pectoralis major ...muscle flap. The pectoralis major flap was used to fill the apical portion of the cavity, while the rectus abdominis flap was used to fill the caudal portion and occlude any bronchial fistula present. All empyemas were treated successfully without recurrence. This method has the advantage of filling apical and caudal parts of the space at once, making effective use of the combined volume of the two flaps.
Autografting of fat pads has a long history in plastic and reconstructive surgery for augmentation of lost soft tissue. However, the results are disappointing because of absorption of the grafts with ...time. The fate of transplanted fat is linked to adipose precursor cells distributed widely in connective tissues. Adipocyte precursor cells can proliferate and mature into adipocytes even in the adult body depending on microenvironment. When reconstituted basement membrane, Matrigel, supplemented with more than 1 ng/ml bFGF was injected s.c. into 6-week-old mice, the neovascularization induced within 1 week was followed by migration of endogenous adipose precursor cells, and a clearly visible fat pad was formed. The pad grew until 3 weeks after the injection and persisted for at least 10 weeks. Such de novo adipogenesis was induced reproducibly by s.c. injection of Matrigel and bFGF over the chest, lateral abdomen, or head. Adipogenesis could be induced even in ear cartilage or in muscle. Thus, our results demonstrated that an abundant population of adipose precursor cells is distributed widely in connective tissues of the adult body and that they migrate into the neovascularized plug of Matrigel for proliferation and maturation. These results suggest a technique of augmenting lost soft tissue in plastic and reconstructive surgery.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
In this study, we examined salvage operations after reexploration in head and neck reconstruction and analyzed ways to solve problems. Free flap reconstruction of the head and neck lesion was carried ...out for 513 cases in our hospital over the past 12 years. Twenty‐one cases of reexploration were caused by postoperative thrombosis (4.1%). We could only salvage seven cases (33.3%) of 21 cases from flap thrombosis. All seven cases were included in the category of venous thrombosis, and they were undertaken within 3 days postoperatively. Our results have shown that once thrombosis occurs, there is little possibility of flap salvage, particularly 3 days after operation and in infectious cases. When no flow phenomena are observed and no flap salvage is deemed possible, aggressive treatment such as a second free flap or next pedicle flap should be chosen as soon as possible to avoid any delay in postoperative treatment.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In free-flap transfer, blood flow in the transferred flap contributes to wound healing and to resistance against infection in the recipient site. Successful reconstructions using free tissue ...transfers may be required to define and choose flaps with abundant blood flow in necessary cases. We investigated blood flow in the flap by transit-time ultrasound flowmeter in 58 free-flap transfers. Flow volume was compared between flap tissues as vascular resistance in the flap was calculated. Fasciocutaneous and osteocutaneous flaps had relatively low blood flow volume, myocutaneous flaps had more, and intraperitoneal flaps had still higher blood flow volume. These differences were statistically significant. Vascular resistance significantly decreased in the same order of comparison. Our findings will help in selecting the most suitable flaps for reconstructive surgery.
While the free fibular osteocutaneous flap is indispensable for mandibular reconstruction, reliable setting is often difficult because relative positions of the bone, skin island, and vascular ...pedicle are critical. We have an algorithm for donor-side selection of free fibular osteocutaneous flap. From July 2002 to March 2004, we performed 15 mandibular reconstructions using free fibular osteocutaneous flaps. We retrospectively classified these procedures as follows. In type I (flap harvested ipsilaterally to defect, n = 5), the skin island was fixed to the oral cavity, and the vascular pedicle emerged from the anterior aspect of the fibula. In type II (flap contralateral to defect, n = 5), the skin island was fixed to the oral cavity, and the vascular pedicle arose from the posterior aspect. In type III (flap contralateral to defect, n = 4), the skin island was fixed to the facial skin and the vascular pedicle arose from the anterior aspect. In type IV (flap ipsilateral to defect, n = 1), the skin island was fixed to the facial skin and the vascular pedicle arose from the posterior aspect. Flaps took completely except in 1 group II case with partial necrosis. Close attention to geometric characteristics of a free fibular osteocutaneous flap facilitates reconstruction of mandibular defects and selection of donor side.
The availability of reliable recipient vessels for free flap transfer in head and neck reconstruction may be limited in cases of prior neck dissection or radiation therapy. One solution is to use the ...internal mammary vessels as recipients for a free omental flap. Five patients were treated with free omental flap transfer using the internal mammary vessels as recipient vessels during head and neck reconstruction. Two patients presented with a pharyngocutaneous fistula, 1 had mandibular osteomyelitis, 1 had primary esophageal cancer, and 1 had bilateral cervical radiation ulcers. All patients had received radiation therapy previously (average dose, 75.4 Gy), and 4 had undergone neck dissection (3 bilateral and 1 ipsilateral). All patients were reconstructed using a free omental flap. Four patients had a second free flap combined with the free omental flap (3 free jejunal flaps and 1 free fibular osteocutaneous flap). The mean follow-up was 26.4 months. All free flaps took entirely, the only complication ileus requiring reoperation in 1 patient. The internal mammary vessels are reliable recipient vessels for a free omental flap in head and neck reconstruction. This procedure is a good option for patients in whom previous surgery or radiation therapy has compromised local recipient vessels.
The free vascularized fibular bone graft, first described in 1975, has become one of the most commonly used bone grafts. It is useful for reconstructing mandibular and traumatic long bone defects and ...defects following tumor resection. This flap, however, does not have a long pedicle and does not have very much volume. The authors report a solution to these problems through the use of an omental flap as a bridge.
Over a 3-year period, nine patients were treated by means of a free fibular osteocutaneous flap with an omental flap. These cases required bone reconstruction without suitable recipient vessels that existed near the defect. The nine patients had the following disorders: two femoral pseudoarthrosis, two tibial pseudoarthrosis, two malignant femoral tumors, one maxillary defect after tumor resection, and one femoral and tibial osteomyelitis.
All flaps were transferred successfully. In one case, an additional skin graft was performed because of partial omental necrosis that occurred within 2 weeks. Fibular synostosis developed in eight cases, but amputation was performed in one case because of failed fibular synostosis. In one case, femoral amputation was performed because the femoral artery became obstructed 3 months postoperatively.
An omental flap has a long pedicle for use as a bridge flap. It is useful as a vascular flap. A combined fibular osteocutaneous and omental flap is useful for bone reconstruction without satisfactory recipient vessels that exist near the defect. Furthermore, the flap is useful for infected wounds.
Cleavage of the extracellular matrix (ECM) by proteolysis unmasks cryptic sites and generates novel fragments with biological activities functionally distinct from those of the intact ECM molecule. ...The laminin G-like (LG)4-5 fragment has been shown to be excised from the laminin α4 chain in various tissues. However, the functional role of this fragment has remained unknown to date. To investigate this, we prepared α4 LG1-3 and α4 LG4-5 fragments by elastase digestion of recombinant α4 LG1-5, and examined their effects on de novo adipogenesis in mice at the site of injection of basement membrane extract (Matrigel) and fibroblast growth factor (FGF)-2. Although the addition of whole α4 LG1-5 suppressed adipogenesis to some extent, the α4 LG4-5 fragment could strongly suppress adipogenesis at a concentration of less than 20 n m. Addition of the α4 LG4 module, which contains a heparin-binding region, had a suppressive effect, but this was lost in mutants with reduced heparin-binding activity. In addition, antibodies against the extracellular domain of syndecan-2 and -4, which are known receptors for the α4 LG4 module, suppressed adipogenesis. Thus, these results suggest that the cryptic α4 LG4-5 fragment derived from the laminin α4 chain inhibits de novo adipogenesis by modulating the effect of FGF-2 through syndecans.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
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