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Chih-Hung Lin

Publications and source records attributed to Chih-Hung Lin.

32 records · Page 2Linked to original sources
PubMed2004

Expression of metallothionein gene during embryonic and early larval development in zebrafish.

Metallothionein (Mt) has been considered as a molecular marker of metal pollution in aquatic ecosystems. Less is known about the expression of mt gene during embryogenesis. Here, we report the cloning, sequencing, and the expression pattern of mt gene during developmental stages in zebrafish. The zebrafish embryogenesis when takes place in a medium containing a dosage of 1000 microM zinc resulted in high mortality, indicating the deleterious effect of zinc on development. The zebrafish mt gene consists of three exons encoding 60 amino acids with 20 conserved cysteine residues. RT-PCR result indicates the maternal contribution of Mt transcripts. Using digoxigenin (DIG)-labeled anti-sense RNA probe, whole-mount in situ hybridization was performed to observe the expression pattern of zebrafish mt gene during embryonic and early larval stages. Stronger as well as ubiquitous expression of mt gene during early embryonic stages narrowed to specific expression after hatching. The mt promoter region contains seven copies of putative metal-responsive elements (MREs), which are shown to be important for the high level activity by deletion analysis. The expression of mt gene during embryogenesis implies its significant role on development.

Amino Acid Sequence↗
PubMed2004

Cloning and characterization of metallothionein gene in ayu Plecoglossus altivelis.

Metallothionein (MT) has been used widely as a potential molecular marker to detect the deleterious effects of heavy metals in aquatic ecosystem. Here we exposed ayu, Plecoglossus altivelis, to zinc (Zn) and tested the distribution as well as the induction of MT in various tissues such as liver, kidney, intestine and stomach. MT induction was significant in liver tissue, followed by kidney and intestine, whereas no induction was detected in stomach. The gene encoding ayu MT was successfully cloned and characterized. Complete nucleotide sequencing and analysis of the 4.5 kb DNA fragment containing the ayu MT gene revealed that the gene has three exons interrupted by two introns, a 5'-flanking region of about 2.5 kb and about 1.6 kb of 3'-flanking region. In grouper heart and kidney cells, the 2.5 kb promoter containing eight metal responsive elements (MREs), two hepatic nuclear factor 5 responsive elements (HNF5REs) and one cAMP responsive element (CRE) had the highest reporter activity.

Amino Acid Sequence↗
PubMed2004

A comparison between primary and secondary toe-to-hand transplantation.

Although primary toe-to-hand transplantation is performed with increasing frequency, its use is still controversial because of the lack of any comparative studies documenting its safety and efficacy. Between August of 1990 and December of 1993, 175 consecutive toe-to-hand transplantations for crush and avulsion injuries were performed in 122 patients. The average interval between injury and primary reconstruction was 7 days, and the average interval between injury and secondary reconstruction was 10.7 months. Follow-up ranged from 18 to 91 months, with an average follow-up of 58 months. There were 31 primary transplantations and 144 secondary transplantations. The survival rate was 96.8 percent (30 of 31) for primary reconstruction and 96.5 percent (139 of 144) for secondary reconstruction. Intraoperative anastomotic revision was necessary in 3.2 percent (one of 31) of primary transplantations and 7.6 percent (11 of 144) of secondary transplantations. Three primary toe-to-hand transplantations (9.7 percent) and 17 secondary toe-to-hand transplantations (11.8 percent) were re-explored in the postoperative period. Each group had one superficial infection. The infection rate was 6.5 percent and 0.7 percent in the primary and secondary groups, respectively. Other complications included partial skin loss, which occurred in one patient (3.2 percent) in the primary group and six patients (4.2 percent of 144 transplantations) in the secondary group. Secondary procedures to improve function were necessary in six secondary transplantations (4.2 percent) and in none of the primary transplantations. There was no statistical difference between the two groups in terms of survival, intraoperative anastomotic revision, re-exploration, future secondary procedure, infection, and complications. This series demonstrates that primary toe-to-hand transplantation can be performed in the suitable candidate safely with as much success as secondary reconstruction. Primary toe transplantation can potentially reduce the overall period of recovery and rehabilitation, allowing the patient to return to work sooner. Further study to evaluate and compare the final functional outcome and return to work time between primary and secondary toe-to-hand transplantation is needed.

Adult↗
PubMed2004

One-stage reconstruction of composite bone and soft-tissue defects in traumatic lower extremities.

Management of bone loss that occurs after severe trauma of open lower extremity fractures continues to challenge reconstructive surgeons. Sixty-one patients who had 62 traumatic open lower extremity fractures and combined bone and composite soft-tissue defects were treated with the following protocol: extensive debridement of necrotic tissues, eradication of infection, and vascularization of osteocutaneous tissue for one-stage bone and soft-tissue coverage reconstruction. The mechanism of injury included 49 motorcycle accidents (80.3 percent), five falls (8.2 percent), three crush injuries (4.9 percent), two pedestrian-automobile accidents (3.3 percent), and two motor vehicle accidents (3.3 percent). The bone defects were located in the tibia in 49 patients (79 percent; one patient had bilateral open tibial fractures), in the femur in seven patients (11.3 percent), in the calcaneus bone in four patients (6.5 percent), and in the metatarsal bones in two patients (3.2 percent). The size of soft-tissue defects ranged from 5 x 9 cm to 30 x 17 cm. The average length of the preoperative bony defect was 11.7 cm. The average duration from injury to one-stage reconstruction was 27.1 days, and the average number of previous extensive debridement procedures was 3.4. Fifty patients had vascularized fibula osteoseptocutaneous flaps, six had vascularized iliac osteocutaneous flaps, and five patients had seven combined vascularized rib transfers with serratus anterior muscle and/or latissimus dorsi muscle transfers. One patient received a second combined rib flap because the first combined rib flap failed. The rate of complete flap survival was 88.9 percent (56 of 63 flaps). Two combined vascularized rib transfers with serratus anterior muscle and latissimus dorsi muscle flaps were lost totally (3.2 percent) because of arterial thrombosis and deep infection, respectively. Partial skin flap losses were encountered in the five fibula osteoseptocutaneous flaps (7.9 percent). Postoperative infection for this one-stage reconstruction was 7.9 percent. Excluding the failed flap and the infected/amputated limb, the primary bony union rate after successful free vascularized bone grafting was 88.5 percent (54 of 61 transfers). The average primary union time was 6.9 months. The overall union rate was 96.7 percent (59 of 61 transfers). The average time to overall union was 8.5 months after surgery. Seven transferred vascularized bones had stress fractures, for a rate of 11.5 percent. Donor-site problems were noted in six fibular flaps, in two iliac flaps, and in one rib flap. The fibular donor-site problems were foot drop in one patient, superficial peroneal nerve palsy in one patient, contracture of the flexor hallucis longus muscle in two patients, and skin necrosis after split-thickness skin grafting in two patients. The iliac flap donor-site problems were temporary flank pain in one patient and lateral thigh numbness in the other. One rib flap transfer patient had pleural fibrosis. Transfer of the appropriate combination of vascularized bone and soft-tissue flap with a one-stage procedure provides complex lower extremity defects with successful functional results that are almost equal to the previously reported microsurgical staged procedures and conventional techniques.

Accidental Falls↗
PubMed2004

Microcirculation study of rabbit ear arterial and venous flow-through flaps using a window chamber model.

Venous flaps are used widely for finger reconstruction because they provide thin tissue, and the flap harvest is associated with less donor-site morbidity. The viability of the venous flap, however, is not as good as that of the ordinary perfused skin flap, and its microcirculation is questionable according to various indirect observations and hypotheses in the literature. Using a window chamber model in a rabbit ear, both arterial and venous flow-through flaps were studied. Factors evaluated were flap viability, flap weight, flap circulation as assessed by laser Doppler flowmetry, and direct observation of the microcirculation. Statistical analysis was performed using the two-sample t test. There was no statistically significant difference in viability between arterial and venous flow-through flaps (p = 0.661). The arterial flow-through flap had better perfusion than thevenous flow-through flap, as measured by laser Doppler perfusion studies (10.40 perfusion units [PU] vs 4.50 PU). However, no statistically significant difference was noted (p = 0.0717). Flap weight assesseed 1 week after surgery and oxygen saturation measured immediately after surgery showed significant differences between the arterial and venous flow-through flaps (p = 0.0001 and 0.0279). These datasuggest that the arterial flow-through flap is subjected to more congestion becauseof the abnormal flow pattern seen, andpossibly because of a superior inflow or nutritional status found in these flaps. Using vital microscopy, direct evaluation of the microcirculation was performed. A to-and-fro phenomenon was noted in both arterial and venous flow-through flaps,which was followed by a reversed direction of flow in part of the microvasculature. With both types of flaps, the blood was directed eventually from the postcapillary venules to the capillaries, through the terminal arterioles, and then to the arterioles. These findings may be explained partially by the normal physiologic pressure gradients present in the microvasculature of these flaps. In this study, direct observation of the microcirculation was used as well as other objective measures to determine the flow patterns and clinical behaviors found in these types of flaps. A model in a rabbit ear for the study of venous and arterial flow-through flaps is described, and clinical correlations are discussed.

Animals↗
PubMed2004

Composite palmaris longus-venous flap for simultaneous reconstruction of extensor tendon and dorsal surface defects of the hand--long-term functional result.

Soft tissue loss in the dorsum of the hand resulting from trauma often involves the extensor mechanism due to its thin skin coverage. When such composite skin and extensor tendon defects occur, the wound could be reconstructed with an ipsilateral forearm venous flap with accompanying palmaris longus tendon. Eighteen dorsal finger defects in 12 patients underwent composite venous flap and tendon transfers in the acute stage. We used both Buck-Gram-cko and Tubiana's methods for objective functional assessments. With the former method, the average composite flexion, extension deficit, and total active motion were 207.2 degrees, 39.0 degrees, and 164.7 degrees, respectively. The average score was 12.1 points, which qualified for a "good" result. With Tubiana's method, the average active flexion was 4.9, and the average extension defect was 2.3. The average score was 7.2 point, which also qualified for a "good" result. Thus, a one-stage composite forearm venous flap could be used to reconstruct dorsal skin and tendon defects of the finger with a predictably good functional outcome.

Acute Disease↗
PubMed2004

Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts.

Traumatic limb injuries requiring free tissue transfer for coverage, often lack healthy recipient vessels adjacent to the defect. In these patients, vein grafts are required to bridge the gap of either the artery, vein or both. For the latter situation, a temporary arteriovenous fistula (AVF) can be created and allowed to mature and then divided and used as recipient artery and veins for the free flap. These cases are challenging and several variables including vein graft length, vein graft diameter, and arterial inflow affect the patency of the vessels and the final outcome of the reconstruction. Sixty-five defects were reconstructed with free tissue transfers using vein grafts of significant length (>20 cm for the arterial gap). The ipsilateral or contralateral great saphenous veins were used for vessel lengthening in all cases. Inflow arteries were either major arteries (superficial femoral, popliteal or brachial), or lesser arteries (sural, anterior or posterior tibial, thoracodorsal, or superior gluteal). The patients were divided into those that underwent AVF followed by free tissue transfer in two stages (n = 6), AVF followed by free tissue transfer in one stage (n = 28) and patients that underwent vein grafting for the arterial defect only with (n = 6) or without (n = 25) a simultaneous bypass graft for lower limb revascularization. In the two-stage AVF group, the rate of occlusion of the graft after AVF creation was 50% (3/6); re-exploration rate was 33.3% (2/6); free flap failure rate was 33.3% (2/6); and limb salvage rate was 83.3% (5/6). In the one-stage AVF group: re-exploration rate was 28.6% (8/28); free flap success rate was 89.3% (25/28); and limb salvage rate was 92.9% (26/28). In the long vein graft group for arterial defects only: re-exploration rate was 25.8% (8/31); free flap success rate was 96.8% (30/31); and limb salvage rate was 87.1% (27/31). In patients where the graft was anastomosed to a major artery the re-exploration rate and free flap failure rate were 22.4% (11/49) and 8.2% (4/49). In patients where the graft was anastomosed to a lesser artery, the re-exploration rate and free flap failure rate were 43.4% (7/16) and 12.5% (2/16). The limb salvage rate was comparable in both groups (89.8%, 44/49, versus 87.5%, 14/16). In all groups, patients undergoing re-exploration were noted to have a an arterial gap of 31.78 cm as compared with the patients that did not require re-exploration which had an arterial gap of 26.26 cm. Vein grafting for bridging vascular defects is a safe procedure when proper indications and techniques are followed. Although a longer graft length seemed to be associated with a higher re-exploration rate, there was no statistical significance. One-stage AVFs can be used with good results, however, two-stage AVFs are associated with a high graft occlusion rate, wound failure rate and limb amputation rate. In all cases, a large caliber graft such as the great saphenous vein provided a large (relatively low resistance) conduit for bridging the defect.

Adolescent↗
PubMed2004

Endoscopically assisted removal of tumors in the frontal region.

BACKGROUND: Advancements in endoscopic surgery, due in part to patient demands and in part to provision of superior medical care by surgeons, have significantly contributed to improvements in patients' quality of life. An endoscopic operation is minimally invasive, associated with faster recovery, and produces less postoperative morbidity. It is a well-accepted procedure in the field of plastic surgery. By applying the principle of endoscopic surgery used in facelift operations, we performed tumor excision in the forehead region. METHODS: Two 1.5-cm slit incisions were made in the anterior hairline. One incision was to allow access for the 4.0-mm, 30 degrees endoscope, and the other was for surgical instrumentation. These incisions, determined by the plane of dissection, were more superficial and below the subgaleal layer for soft tissue tumors and deeper into the subperiosteal layer for bone tumors. With good illumination and magnified monitor viewing, the tumors could clearly be visualized and were completely excised. RESULTS: Seven patients with either dermoid cysts (3), osteomas (2), or lipomas (2) underwent endoscopically assisted procedures. In all cases, tumors were successfully excised with no acute or chronic complications. The average postoperative follow-up period was 7 months. No incidence of tumor recurrence was reported. All patients were satisfied with the resultant forehead contour and surgical scars. CONCLUSIONS: The main advantage of this procedure is the fact that it is minimally invasive, thus reducing the incidence of injury to the neurovascular structures of the forehead as well as minimization of scar visibility. In conclusion, an endoscope-assisted approach is a good alternative method for managing benign soft-tissue and bone tumors in the forehead and brow region.

Adolescent↗
PubMed2003

The similarities and diversities of signal pathways leading to consolidation of conditioning and consolidation of extinction of fear memory.

It is generally believed that consolidation of long-term memory requires activation of protein kinases, transcription of genes, and new protein synthesis. However, little is known about the signal cascades involved in the extinction of memory, which occurs when the conditioned stimulus is no longer followed by the unconditioned stimulus. Here, we show for the first time that an intra-amygdala injection of transcription inhibitor actinomycin D at the dose that blocked acquisition failed to affect extinction of a learned response. Conversely, protein synthesis inhibitor anisomycin blocked both acquisition and extinction. Extinction training-induced expression of calcineurin was blocked by anisomycin but not by actinomycin D. NMDA receptor antagonist, phosphatidylinositol 3-kinase (PI-3 kinase), and MAP kinase inhibitors that blocked the acquisition also blocked the extinction of conditioned fear. Likewise, PI-3 kinase inhibitor blocked fear training-induced cAMP response element-binding protein (CREB) phosphorylation as well as extinction training-induced decrease in CREB phosphorylation, the latter of which was associated with calcineurin expression and could be reversed by a specific calcineurin inhibitor. Thus, molecular processes that underlie long-term behavioral changes after acquisition and extinction share some common mechanisms and also display different characteristics.

Acoustic Stimulation↗
PubMed2003

Identification of calcineurin as a key signal in the extinction of fear memory.

Memory extinction refers to a gradual decrease of the previously acquired response when exposed to conditional stimulus without pairing with unconditional stimulus. Here we show for the first time that fear training-induced phosphorylation of specific substrates in the rat amygdala is reduced after extinction trials and is accompanied by an increase in the protein level and enzymatic activity of calcineurin. In parallel, calcineurin inhibitors prevented extinction-induced protein dephosphorylation as well as extinction of fear memory. Thus, extinction training increased phosphatase activity likely via an expression of calcineurin. Calcineurin then created a negative-feedback loop and directly or indirectly dephosphorylated specific substrates, which, in their phosphorylated state, were required for memory consolidation. Accordingly, in our experimental condition, extinction could be ascribed at least in part to a weakening of the original signaling.

Amygdala↗
PubMed2002

Technique and strategy in anterolateral thigh perforator flap surgery, based on an analysis of 15 complete and partial failures in 439 cases.

The free anterolateral thigh flap is becoming one of the most preferred options for soft-tissue defect reconstruction. Between June of 1996 and August of 2000, 672 anterolateral thigh flaps were used in 660 patients in Chang Gung Memorial Hospital. A total of 439 flaps were cutaneous or fasciocutaneous flaps based on musculocutaneous perforators. The analysis of the flap failures was done only in this perforator series. In six cases, no suitable skin vessel was found during the dissection of the flaps. The complete success rate was 96.58 percent (424 of 439). Of the 15 failure cases, eight were complete and seven were partial (10 percent to 60 percent of the flap). Thirty-four flaps were reexplored, and 19 (56 percent) were salvaged. In this study, some of the reasons for the flap failure, unique to the anterolateral thigh perforator flap, were identified. They include inadvertent division of perforator at the fascial plane as a result of inadequate knowledge of perforator anatomy, inadvertent injury to the perforator during intramuscular dissection (noted by the surgeon or ignored) as a result of inexperience, and twisting of the pedicle during inset of the flap at the recipient site. Technical pearls in the harvest of the anterolateral thigh perforator flap are as follows: mapping of the skin vessels with a Doppler probe before flap design, meticulous dissection of the perforator under surgical loupe or even lower-magnification microscope, inclusion of a small fascia cuff around the perforator, and intermittent topical use of Xylocaine during the intramuscular dissection of the perforators. During reexploration, one must search for twisting of the pedicle and small bleeders from the branches of the intramuscular perforators.

Adolescent↗