Functional modulation of human macrophages through CD46 (measles virus receptor): production of IL-12 p40 and nitric oxide in association with recruitment of protein-tyrosine phosphatase SHP-1 to CD46

Human CD46, formerly membrane cofactor protein, binds and inactivates complement C3b and serves as a receptor for measles virus (MV), thereby protecting cells from homologous complement and sustaining systemic measles infection. Suppression of cell-mediated immunity, including down-regulation of IL-12 production, has been reported on macrophages (Mphi) by cross-linking their CD46. The intracellular events responsible for these immune responses, however, remain unknown. In this study, we found that 6- to 8-day GM-CSF-treated peripheral blood monocytes acquired the capacity to recruit protein-tyrosine phosphatase SHP-1 to their CD46 and concomitantly were able to produce IL-12 p40 and NO. These responses were induced by stimulation with mAbs F(ab')(2) against CD46 that block MV binding or by a wild-type MV strain Kohno MV strain (KO; UV treated or untreated) that was reported to induce early phase CD46 down-regulation. Direct ligation of CD46 by these reagents, but not intracellular MV replication, was required for these cellular responses. Interestingly, the KO strain failed to replicate in the 6- to 8-day GM-CSF-cultured Mphi, while other MV strains replicated to form syncytia under the same conditions. When stimulated with the KO strain, rapid and transient dissociation of SHP-1 from CD46 was observed. These and previous results provide strong evidence that CD46 serves as a signal modulatory molecule and that the properties of ligands determine suppression or activation of an innate immune system at a specific maturation stage of human Mphi.

A novel beta-catenin-binding protein inhibits beta-catenin-dependent Tcf activation and axis formation

beta-Catenin is efficiently phosphorylated by glycogen synthase kinase-3beta in the Axin complex in the cytoplasm, resulting in the down-regulation. In response to Wnt, beta-catenin is stabilized and translocated into the nucleus where it stimulates gene expression through Tcf/Lef. Here we report a novel protein, designated Duplin (for axis duplication inhibitor), which negatively regulates the function of beta-catenin in the nucleus. Duplin was located in the nucleus. Duplin bound directly to the Armadillo repeats of beta-catenin, thereby inhibiting the binding of Tcf to beta-catenin. It did not affect the stability of beta-catenin but inhibited Wnt- or beta-catenin-dependent Tcf activation. Furthermore, expression of Duplin in Xenopus embryos inhibited the axis formation and beta-catenin-dependent axis duplication, and prevented the beta-catenin's ability to rescue ventralizing phenotypes induced by ultraviolet light irradiation. Thus, Duplin is a nuclear protein that inhibits beta-catenin signaling.

Microvascular anastomoses using an Nd-YAG laser

The authors performed anastomoses of small vessels with the Nd-YAG laser, comparing these with conventional suture anastomoses. Some arteries were sutured with 10-0 nylon with about eight suture sites, and others were held by stay sutures at three points with laser irradiation performed between them. Two surgeons performed the anastomoses in the same way. The first was well-trained and experienced, and the second was technically inexperienced. The authors evaluated clamping time, patency rate, and endoscopic and histologic findings. The patency rate of the first surgeon was 100 percent (30/30) in the suture anastomoses and was 97 percent (29/30) in the laser anastomoses. For the second surgeon, the rates were 60 percent (18/30) in the suture group and 80 percent (24/30) in the laser group. On histologic examination, the suture group showed inflammatory cells around the suture site at the fourth week after the operation. In the laser group, an inflammatory reaction around the suture material was observed, but the other areas recovered. For the experienced surgeon, the patency rate and clamping time of the laser anastomosis provided no statistically significant difference to those of the suture anastomosis. On the other hand, for the inexperienced surgeon, the patency rate of the laser anastomosis was superior to that of the suture anastomosis, and the clamping time of the laser anastomosis was shorter than that of the suture anastomosis. Therefore, the authors concluded that the Nd-YAG laser anastomosis is useful for small vessels.

Effects of rat Axin domains on axis formation in Xenopus embryos

Wnt signaling plays an important role in axis formation in early vertebrate development. Axin is one Wnt signaling regulator that inhibits this pathway. The effects of the injection of mRNA of several rat Axin (rAxin) mutants on axis formation in Xenopus embryos were examined. It was found that rAxin mutants containing only a regulation of G-protein signaling (RGS) domain fragment or with deletion of the RGS domain induced axis formation. Because the RGS domain is a major adenomatous polyposis coli gene product (APC)-binding domain, APC association with glycogen synthase kinase 3beta (GSK3beta) on the Axin molecule may be important in inhibition of axis formation. The ventralizing activities of wild-type rAxin and a mutant in which the Dishevelled and Axin (DIX) domain was deleted (deltaDIX mutant) were examined. Histological examination and gene expression revealed that the ventralizing activity of the deltaDIX mutant was weaker than that of wild-type rAxin. This finding suggests that the C-terminus of rAxin contributes to the inhibition of Wnt signaling in Xenopus embryos. Furthermore, an rAxin mutant that contained both the RGS and GSK3beta-binding domains affected both the dorsal and ventral sides of blastomeres, mediated ectodermal fate and induced expansion of notochord and/or endoderm, but did not induce axis formation.

A reverse ulnar hypothenar flap for finger reconstruction

A reverse-flow island flap from the hypothenar eminence of the hand was applied in 11 patients to treat palmar skin defects, amputation injuries, or flexion contractures of the little finger. There were three female and eight male patients, and their ages at the time of surgery averaged 46 years. A 3 x 1.5 to 5 X 2 cm fasciocutaneous flap from the ulnar aspect of the hypothenar eminence, which was located over the abductor digiti minimi muscle, was designed and transferred in a retrograde fashion to cover the skin and soft-tissue defects of the little finger. The flap was based on the ulnar palmar digital artery of the little finger and in three patients was sensated by the dorsal branch of the ulnar nerve or by branches of the ulnar palmar digital nerve of the little finger. Follow-up periods averaged 42 months. The postoperative course was uneventful for all patients, and all of the flaps survived without complications. The donor site was closed primarily in all cases, and no patient complained of significant donor-site problems. Satisfactory sensory reinnervation was achieved in patients who underwent sensory flap transfer, as indicated by 5 mm of moving two-point discrimination. A reverse island flap from the hypothenar eminence is easily elevated, contains durable fasciocutaneous structures, and has a good color and texture match to the finger pulp. This flap is a good alternative for reconstruction of palmar skin and soft-tissue defects of the little finger.

Spontaneous thyroid-containing teratoma associated with impaired development in the African clawed frog, Xenopus laevis

Teratomas are rare in amphibians and the neoplasm described here, which had a significant thyroid carcinoma component, is the first tumour of this type to be reported in Xenopus laevis. The thyroid component contained moderately to well-differentiated acinar glands showing much hyperplasia, dysplasia, and reduced and distorted colloid reservoirs. Cartilaginous, neural, muscular, mesenchymal and gut-like epithelial components were also observed in this ventral mediastinal neoplasm, indicating aberrant proliferation from all three germ layers. This teratoma was only one abnormality in a complex of developmental changes, followed for 28 months, which appeared in a single generation of sibling 2-week-old Xenopus larvae. Two hundred larvae produced by an apparently normal adult pair initially showed ocular defects, including microphthalmia, anophthalmia and tumours projecting near the eyes. During further development up to 28 months, mediastinal tumours developed in nine frogs; these tumours were associated with reduced growth, the frogs reaching only 13-20% of normal weight, and greatly enhanced ventral pigmentation.

Progenitor endothelial cells on vascular grafts: an ultrastructural study

The morphology of progenitor endothelial cells on vascular graft surfaces is addressed in this report. Such cells were seen to attach to intima-expressed CD34 and Flk-1 antigen and showed positive 5-bromo-2-deoxyuridine (BrdU) uptake. We examined CD34 and Flk-1 antigen-expressing endothelial progenitor cells three-dimensionally using confocal laser scanning microscopy (CLSM). Under detailed CLSM observation, through an ameboid-form cell, these progenitor endothelial cells changed from a globular to a flattened form. We also investigated these morphological changes using scanning electron microscopy. From these results, progenitor endothelial cells were observed not only near the advancing edge of endothelium, but also around the developing intimal site. Their form also changed from globular to flattened as observed in the CLSM results. These morphological changes were seen more frequently near the advancing edge and around the developing intimal site. They attached directly to vascular prosthesis fibers and likewise covered the graft luminal surface. Progenitor endothelial cells in any form had a common surface structure. We conclude from our results that progenitor endothelial cells can attach to graft fibers directly without clotting and directly cover the graft luminal surfaces.

Dobutamine stress echocardiography for the diagnosis of myocardial viability: assessment of left ventricular systolic velocities in longitudinal axis by pulsed Doppler tissue imaging

Dobutamine (DOB) stress two-dimensional echocardiography is an established method for the detection of viable myocardium, but conventional assessment of wall motion is subjective. We measured quantitatively the left ventricular systolic velocities along the longitudinal axis by pulsed Doppler tissue imaging (DTI). In 30 patients with previous myocardial infarction, pulsed DTI focused on the infarct area was performed from an apical two- or four-chamber view before and during DOB (10 microg/kg/min) stress one day before coronary angioplasty. We calculated peak systolic velocity (S), regional pre-ejection period (PEP, the time interval from the onset of QRS to the onset of systolic wave) and regional ejection time (ET). Left ventriculography was obtained before and 3 months after coronary angioplasty to assess regional wall motion. Improvement of abnormal wall motion was observed in 19 patients (group P) but not in 11 (group N). Group P had significantly larger S and smaller PEP/ET than group N during DOB stress, although there were no significant differences in these indices between the groups at baseline. As a consequence, group P had a significantly larger percent change in S and a smaller percent change in PEP/ET than group N (164+/-39 vs 117+/-20% and 88+/-17 vs 116+/-29%, respectively, p < 0.01). It is suggested that the quantitative measurement of longitudinal systolic velocities during DOB stress by DTI is useful for the precise assessment of myocardial viability.

[Relationship between obesity, total plasma cholesterol and blood pressure in male adults]

I investigated the relationship between the percentage of body fat, Body Mass Index (BMI) and total plasma cholesterol and blood pressure. The percentage of body fat was measured by the bioelectrical impedance method. The subjects investigated were 2,955 men aged from 23 to 59 years, who were working in a company making machinery. They were divided into four groups as follows. The normal group were within the normal BMI range (< 24) and body fat percentage range (< 20%). The seemingly obese group were over the normal BMI (> or = 24) and normal percentage of body fat range. The occult obesity group were within the normal BMI range and over the normal percentage of body fat range (> or = 20%). The obese group were over the BMI and percentage of body fat range. In each group, those who had high total plasma cholesterol and blood pressure were counted. The number of those who had high total plasma cholesterol was significantly larger in the obese group than in the seemingly obese group and the normal group, and larger in the occult obesity group than in the seemingly obese group and normal group and larger in the seemingly obese group than in the normal group. The number of those who had high systolic blood pressure was significantly larger in the obese group than in the occult obesity group, the seemingly obese group and the normal group, larger in the occult obesity group than in the normal group and larger in the seemingly obese group than in the normal group. The number of those who had high diastolic blood pressure was significantly larger in the obese group than in the occult obesity group, and the seemingly obese group and the normal group, larger in the occult obesity group than in the normal group, and larger in the seemingly obese group than in the normal group. These results suggest that measurement of percent body fat is useful in preventing adult diseases in employees with a high percentage of body fat, but who show no sign of abnormality in medical examinations, and those who are considered to be obese according to their BMI or percentage of body fat have a high risk of adult diseases.

Free and island flap transfer for soft tissue defects in the hand and forearm

Two hundred twenty patients with soft tissue defects in the hand and forearm were treated with 226 free and island flap transfers. Reconstructed sites involved the thumb in 74 cases, the fingers in 117, the hand in 30, and the forearm in 5. Seventy-nine patients received 82 free flaps, and 141 patients received 144 island flaps. Fifty-six finger reconstruction cases and 73 of 74 thumb reconstruction cases had sensory flap transfers. In the free flap transfer group, 77 flaps survived (93.9%), and 5 failed. In the island flap transfer group, 140 flaps survived (97.2%), and 4 failed. Of the five-failures in the free flap transfers, four were dorsalis pedis flaps, two of which were on patients with an arteriovenous fistula. Of the four failures in the island flap transfers, two were posterior interosseous flaps and two were digital island flaps. All four were reverse-flow island flaps.

Expression of the Xenopus GTP-binding protein gene Ran during embryogenesis

The Ran gene family encodes small GTP binding proteins that are associated with a variety of nuclear processes. We isolated a Xenopus Ran cDNA and analyzed the pattern of expression of this gene during embryogenesis. Ran is expressed maternally and later in the CNS, neural crest, mesenchyme, eyes, and otic vesicles. However, expression is not detected in the somites or the notochord.

XSIP1, a member of two-handed zinc finger proteins, induced anterior neural markers in Xenopus laevis animal cap

We characterized Xenopus SIP1 (XSIP1), Smad interacting protein, from activin-treated animal caps by differential screening. The XSIP1 is very similar to mouse SIP1 in the protein coding region including the zinc finger domain and homeodomain. The expression pattern was analyzed by RT-PCR and whole mount in situ hybridization. XSIP1 expression was initially restricted to the dorsal marginal zone in the late gastrula and was subsequently expressed at the lateral edge of neural plate and, in the tailbud stage, in the forebrain, neural tube, and eye. Overexpression of XSIP1 at the animal caps resulted in activation of anterior neural markers without mesodermal markers. Ectopic expression of XSIP1 induced enlargement of neural cells and disordered eye formation. In addition to abnormal head phenotypes, many embryos were short-tailed. Our findings suggest that XSIP1 is a transcriptional repressor, which may be involved in the activin-dependent signal pathway.

The role of serum imbibition for skin grafts

Numerous studies of grafted skin suggest that full-thickness skin grafts are nourished by exudate from the recipient bed called a serum imbibition. However, whether serum imbibition by itself is sufficient for nourishment of skin grafts has not been shown definitely and directly. To clarify the role of serum imbibition, we performed a comparative study between 20 skin grafts and 20 musculocutaneous flaps. The nourishment of the cell in the skin graft is by serum imbibition. That in musculocutaneous flaps is mainly derived from blood supply. We evaluated the nourishment by means of the unique characteristics of the cell cycle. Once cells are put into a synthetic phase, they cannot reverse or stop the progress of the cell cycle. To take advantage of this characteristic of the cell cycle, prewounding methods (40 flaps were lifted once and put back to the original sites prior to the evaluation) were intended for the cells in pre-elevated skin to turn into a proliferating phase. Cells were examined by antibody against proliferating cell nuclear antigen immunohistologically, to determine whether they had turned into the proliferating phase or not. After 3 days, all flaps were reelevated; half (20 flaps) had their muscle layer and the neurovascular bundle removed to make a full-thickness skin graft. The rest (20 flaps) were only lifted. They were sutured back to the original sites. Ten skin grafts and musculocutaneous flaps each were harvested at 3 hours (1st day) and at 11 days (11th day) after the second operation. Bromodeoxyuridine, which is a thymidine analog and is taken into the cells in the synthetic phase, was introduced intraperitoneally 2 hours before the harvest. All flaps and grafts were evaluated histologically and immunohistologically. Proliferating cell nuclear antigen analysis showed that the prewounding method induced the cells of skin grafts and musculocutaneous flaps to proliferate before the implantation. Regarding the bromodeoxyuridine uptake, no significant differences could be seen between skin grafts and musculocutaneous flaps irrespective of their different nourishment. No structural changes, such as degenerative or necrotic, could be seen at the hair follicle and other glands even at the 11th day. Almost all of the layers of skin grafts survived as long as they were checked by light microscopy (hematoxylin and eosin stain). No differences could be seen between musculocutaneous flaps and skin grafts or between the 1st and 11th days in this study. We concluded that serum imbibition is sufficient for nourishment of skin grafts, just as blood supply is sufficient for nourishment of musculocutaneous flaps.

Activin incorporation into vitellogenic oocytes of Xenopus laevis

Activin uptake into Xenopus oocytes was studied by several complementary methods. Immunocytochemistry of adult ovary localized activin and follistatin in the cytoplasm of vitellogenic oocytes and surrounding follicle cells. Surface plasmon resonance analysis of protein interaction kinetics indicated that while follistatin or a complex of activin-follistatin bound to yolk vitellogenin, activin alone did not. Radioactive tracer analysis measured specific incorporation of activin by viable oocytes in vitro. Together, the results suggest that vitellogenic oocytes can import activins from follicle cells and that follistatin may act as a chaperone for binding activin to vitellogenin in yolk platelets.

Natural killer cell subpopulations and cytotoxicity for infertile patients undergoing in vitro fertilization

PROBLEM

We evaluated the participation of the lymphocyte subpopulations in the endometrium and peripheral blood on in vitro fertilization and embryo transfer (IVF-ET) outcomes.

METHOD OF STUDY

Peripheral blood samples were analyzed for the expression of CD3, CD4, CD8, CD16, and CD56, using a FACScan, and for natural killer (NK) cell cytotoxicity, using a 51Cr assay. Endometrial samples obtained at a previous phase of the IVF cycle were analyzed for the expression of CD16 and CD56, using a FACScan.

RESULTS

The percentages of CD56+ cells and CD16+CD56+ cells in the peripheral blood on the day of ET were significantly higher in the failed group than in the implanted group. In the endometrial tissue, the increase of the percentage of CD16+CD56dim cells and the decrease of the percentage of CD16-CD56bright cells in the aborted group were significant when compared with the those of the delivered group.

CONCLUSIONS

The increase of cytotoxic NK cells in the peripheral blood and the endometrium may affect the therapeutic results of IVF-ET. It was suggested that modifications of NK cytotoxicity or of NK subpopulations might contribute to the improvements of IVF outcomes.

Elevated circulating levels and cardiac secretion of soluble Fas ligand in patients with congestive heart failure

The circulating levels of soluble Fas ligand was increased in patients with advanced congestive heart failure. This study also indicates that the failing heart may contribute to the increased concentration of soluble Fas ligand in patients with congestive heart failure.

Molecular remodeling of complement regulatory proteins for xenotransplantation

In pig-to-human discordant xenotransplantation, human complement is a major barrier against long survival of xenografts. Human complement regulatory proteins expressed on xenografts have been adapted as safeguards against host-induced hyperacute rejection of xenografts. For successful xenotransplantation, there have been many attempts to generate molecules with potent human complement regulatory activity but without activities related to harmful functions such as infection, immunosuppression and signal transduction devastating cellular homeostasis. Here, we summarize the strategy by which molecules for xenotransplantation should be designed and propose a GPI-anchored form of monomeric human C4bp as a candidate for efficient protection of swine xenografts from human complement attack.

Transfer of a pedicled venous flap containing perivenous areolar tissue and nerve: an experimental study

In this paper, we evaluated experimentally the feasibility of transferring a pedicled venous flap with perivenous areolar tissue into an ectopic site and investigated the role of each vein, the perivenous areolar tissue and nerve in the viability of pedicled venous flaps. Three groups of flaps were created using a rabbit-ear model: Group 1 (n = 11), containing perivenous areolar tissue and a draining vein; Group 2 (n = 10), perivenous areolar tissue, a draining vein and nerve; Group 3 (n = 10), only perivenous areolar tissue. Macroscopic, angiographic and histological assessments were performed 14 days after transfer. The total survival areas including superficial necrosis of Groups 1, 2 and 3 were 52.7%, 82.5% and 0%, respectively. There were significant differences in mean survival area and mean total survival area including superficial necrosis between Group 1 and Group 2 (P < 0.05). In contrast, all flaps in Group 3 became necrotic. These data suggest that a preserved vein is the necessary condition, and additional arterial flow through the preserved nerve and a small vascular network within the areolar tissue may play an important role in flap survival.

Evidence that far-infrared radiation promotes growth of Xenopus laevis

In most ectotherms, environmental temperature has differential effects on growth and differentiation. For example, amphibian size at maturity decreases with increasing temperature. To address how radiant heat in the form of far-infrared radiation (FIR) may affect development of the aquatic ectotherm Xenopus laevis, we continuously irradiated swimming larvae as they developed into young adults. Here we report evidence that FIR promotes growth of these organisms in an aqueous environment.

Effect of mutations at the residues R25, D27, P69, and N70 of B95a-MCP on receptor activities for the measles viruses Nagahata wild-type strain and CAM vaccine strain

Human membrane cofactor protein (MCP, CD46) is a regulator of complement activation and also serves as a receptor for measles virus (MV). We recently isolated an MCP homolog from B95a, an Epstein-Barr virus-transformed marmoset B-lymphoblastoid cell line, which is 76% identical to human-MCP. B95a-MCP acts as an MV receptor for CAM, a vaccine strain of MV, but not for Nagahata, wild-type MV strain. The four residues in human-MCP (Asp27, Lys29, Arg69, and Asp70) are reportedly MV binding sites, and these are changed in B95a-MCP (Glu27, Asp29, Pro69, and Asn70). In the present study, we constructed B95a-MCP mutants by replacing the four residues with those in human-MCP, and tested whether the Chinese hamster ovary (CHO) transfectants expressing B95a-MCP mutants become susceptible to the Nagahata strain. The CHO transfectants expressing B95a-MCP mutants formed syncytium with the CAM strain but not with the Nagahata strain. The binding of the hemagglutinin (H) of MV with B95a-MCP mutants was observed with the CAM strain but not with the Nagahata strain. These results suggest that the failure of B95a-MCP as the MV receptor for the Nagahata strain is not due simply to the natural mutations at these four residues. The critical residues for MV binding in an MCP molecule seem to differ depending upon the structure of the MV H protein.

Reducing multiple pregnancies by restricting the number of embryos transferred to two at the first embryo transfer attempt

Though the multiple pregnancy rate in in-vitro fertilization-embryo transfer must be reduced, strict and uniform regulation of the number of embryos transferred may make it impossible for women with little natural fecundity to carry children. We therefore restricted the number of embryos per transfer. In the first half of the observation period (n = 100), we limited the number of embryos transferred to three regardless of the number of previous transfers. In the second half (n = 137), we strictly regulated the number of embryos transferred to two at the first attempt and three in the second and later attempts. The multiple pregnancy rate per pregnancy was significantly lower (P < 0.005) in the second period (20.4%) than in the first period (52.9%), while the clinical pregnancy rate and the implantation rate per transfer were similar in both observation periods. 60.7% (17/28) of the multiple pregnancies arose from the first embryo transfer attempt, and 17.9% (5/28) of them arose from a second attempt. The 18 multiple pregnancies in the first period involved six sets of triplets, while the 10 multiple pregnancies that arose in the second period all involved twins. The implantation rate per transfer at the first attempt was significantly higher than that at the second or later attempts. The criterion for determining the number of embryos transferred should be simple to minimize errors of judgement. We believe that our method of restricting the numbers of embryos transferred may be one method of reducing multiple pregnancies without eliminating the possibility of having children for women with low fecundity.

Histologic findings in polyacrylamide-coated polytetrafluoroethylene (PTFE) arterial grafts in the rat abdominal aorta

To improve cell attachment without inducing thrombogenesis, the authors coated the inner surface of polytetrafluoroethylene (PTFE) prostheses (I.D.: 1 mm; length: 10 mm; wall thickness: 0.5 mm; fibril length: 30 microm) with polyacrylamide (PAA), known to have a strong antithrombotic effect (PAA-PTFE). They implanted the prostheses into the abdominal aorta of rats, and retrieved them at intervals of up to 9 months. Graft healing was observed under light and scanning electron microscopy. All the inner surfaces of the grafts examined were barely covered with fibrin or platelets. The PAA-coated fibers had many projections, in contrast to the original PTFE prostheses. Neo-endothelium was observed to be directly attached to these structural fibers of the PAA-PTFE grafts. Restoration of the neointima was also observed in these vascular prostheses.

Subzero nonfreezing preservation in a murine limb replantation model

This study was designed to examine the most effective temperature for hypothermic storage, without freezing, to prolong ischemic tolerance in an amputated murine hindlimb model. We measured freezing points in the calf muscle and the subcutaneous tissue of the foot in the amputated limbs of Fisher 344 strain male inbred rats. The highest freezing point was -1.5 degrees C, which was recorded in the calf muscle. To prevent freezing in any of the tissues in the amputated limb, the temperature for the lowest nonfreezing preservation was defined as -1 degrees C. The amputated limbs were preserved at subzero nonfreezing temperature (-1 degrees C) and at 4 degrees C for 4, 8, 12, 24, 48, and 72 h, and were then transplanted to other inbred rats by microsurgical techniques. We evaluated the vascular patency of the anastomoses by direct observation and performed histological examinations on the seventh day after replantation. Subzero nonfreezing preservation of a limb at -1 degrees C for 72 h was significantly superior to hypothermic preservation at 4 degrees C for 72 h in terms of anastomotic patency rates (P < 0.05). The histology of skeletal muscles preserved at -1 degrees C for 8 h showed greater similarity to the normal situation than the histology of those preserved at 4 degrees C for 8 h. Bone viability with osteoblastic activity was maintained in grafted limbs preserved at -1 degrees C for 72 h, but in the limbs preserved at 4 degrees C for 72 h the bone was not viable, showing no osteoblastic activity. Clinically, the period of ischemia in major limb replantation at normal ambient temperatures is limited to about 6 h. In this study, the maximum ischemia time for replantation of a limb containing muscle tissue was prolong to 8 h at -1 degrees C, but the maximum ischemia time at 4 degrees C could not be prolonged to 8 h. Our results suggest that, in the major replantation of a limb containing muscular tissue, hypothermic preservation at -1 degrees C would be more useful than preservation at 4 degrees C.