Upper extremity limb salvage with microvascular reconstruction in patients with advanced sarcoma

Limb salvage is a viable alternative to amputation in many cases of advanced sarcoma. The authors examined their experience with microvascular reconstruction of upper extremity defects after sarcoma resection, focusing on oncologic and functional outcomes. A retrospective analysis yielded 17 patients who underwent 18 free flap procedures and met the inclusion criteria. Most patients (71 percent, n = 12) had recurrent sarcoma at presentation to the authors' institution. Malignant fibrous histiocytoma was the most common pathologic subtype (n = 6). High-grade tumors were present in 94 percent of patients (n = 16). The free flap survival rate was 100 percent. The rectus abdominis flap was the most common free flap used (39 percent; n = 7). Local recurrence occurred in nine flaps (50 percent), and five patients ultimately required amputations. Six patients (35 percent) had distant recurrence. The mean Enneking score for limb function was 73 percent of the maximum (21.9 of 30). The 5-year disease-specific survival rate was 61.3 percent. In select patients with advanced upper extremity sarcoma undergoing limb salvage, microvascular flap reconstruction can provide reliable, safe coverage with reasonable preservation of function.     

Uterine extracellular matrix components are altered during defective decidualization in interleukin-11 receptor α deficient mice

Background

Implantation of the embryo and successful pregnancy are dependent on the differentiation of endometrial stromal cells into decidual cells. Female interleukin-11 receptor α (IL-11Rα) deficient mice are infertile due to disrupted decidualization, suggesting a critical role for IL-11 and its target genes in implantation. The molecular targets of IL-11 in the uterus are unknown, but it is likely that IL-11 signaling modifies the expression of other genes important in decidualization. This study aimed to identify genes regulated by IL-11 during decidualization in mouse uterus, and to examine their expression and localization as an indication of functional significance during early pregnancy.

Methods

Decidualization was artificially induced in pseudopregnant wild type (IL11Ra^+/+) and IL-11Rα deficient (IL11Ra^-/-) littermates by oil injection into the uterine lumen, and gene expression analyzed by NIA 15K cDNA microarray analysis at subsequent time points. Quantitative real-time RT-PCR was used as an alternative mRNA quantitation method and the expression and cellular localization of the protein products was examined by immunohistochemistry.

Results

Among 15,247 DNA probes, 13 showed increased and 4 decreased expression in IL11Ra^-/- uterus at 48 h of decidualization. These included 4 genes encoding extracellular matrix proteins; collagen III α1, secreted acidic cysteine-rich glycoprotein (SPARC), biglycan and nidogen-1 (entactin). Immunohistochemistry confirmed increased collagen III and biglycan protein expression in IL11Ra^-/- uterus at this time. In both IL11Ra^-/- and wild type uterus, collagen III and biglycan were primarily localized to the outer connective tissue and smooth muscle cells of the myometrium, with diffuse staining in the cytoplasm of decidualized stromal cells.

Conclusion

These data suggest that IL-11 regulates changes in the uterine extracellular matrix that are necessary for decidualization.

     

Nitric oxide and Fenton/Haber-Weiss chemistry: nitric oxide is a potent antioxidant at physiological concentrations

We have examined the action of nitric oxide (NO) on the ability of Fenton's reagent (ferrous iron and hydrogen peroxide), to oxidize a number of organic optical probes. We found that NO is able to arrest the oxidation of organic compounds at concentrations of NO found in brain, in vivo. We present evidence that Fenton's reagent proceeds via a ferryl intermediate ([Fe[double bond]O]2+), before the generation of hydroxyl radical *OH. NO reacts rapidly with this ferryl, blocking the production of *OH. We propose that NO has an important role in protecting biological tissues, and the brain in particular, from Fenton chemistry.     

Mechanism of pressure-induced thermostabilization of proteins: studies of glutamate dehydrogenases from the hyperthermophile Thermococcus litoralis

In this study, we investigated the effect of pressure on protein structure and stability at high temperature. Thermoinactivation experiments at 5 and 500 atm were performed using the wild-type (WT) enzyme and two single mutants (D167T and T138E) of the glutamate dehydrogenase (GDH) from the hyperthermophile Thermococcus litoralis. All three GDHs were stabilized, although to different degrees, by the application of 500 atm. Interestingly, the degree of pressure stabilization correlated with GDH stability as well as the magnitude of electrostatic repulsion created by residues at positions 138 and 167. Thermoinactivation experiments also were performed in the presence of trehalose. Addition of the sugar stabilized all three GDHs; the degree of sugar-induced thermostabilization followed the same order as pressure stabilization. Previous studies suggested a mechanism whereby the enzyme adopts a more compact and rigid structure and volume fluctuations away from the native state are diminished under pressure. The present results on the three GDHs allowed us to further confirm and refine the proposed mechanism for pressure-induced thermostabilization. In particular, we propose that pressure stabilizes against thermoinactivation by shifting the equilibrium between conformational substates of the GDH hexamer, thus inhibiting irreversible aggregation.     

Stable and transient expression of chimeric peroxisomal membrane proteins induces an independent "zippering" of peroxisomes and an endoplasmic reticulum subdomain

Peroxisomal ascorbate peroxidase (APX) (EC 1.11.1.11) was shown recently to sort through a subdomain of the ER (peroxisomal endoplasmic reticulum; pER), and in certain cases, alter the distribution and/or morphology of peroxisomes and pER when overexpressed transiently in Nicotiana tabacum L. cv. Bright Yellow 2 (BY-2) cells. Our goal was to gain insight into the dynamics of peroxisomal membrane protein sorting by characterizing the structure and formation of reorganized peroxisomes and pER. Specifically, we test directly the hypothesis that the observed phenomenon is due to the oligomerization of cytosol-facing, membrane-bound polypeptides. a process referred to as membrane "zippering". Results from differential detergent permeabilization experiments confirmed that peroxisomal APX is a C-terminal "tail-anchored" (Cmatrix-Ncytosol) membrane protein with a majority of the polypeptide facing the cytosol. Transient expression of several APX chimeras whose passenger polypeptides can form dimers or trimers resulted in the progressive formation of "globular" peroxisomes and circular pER membranes. Stable expression of the trimer-capable fusion protein yielded suspension cultures that reproducibly maintained a high degree of peroxisomal globules but relatively few detectable pER membranes. Electron micrographs revealed that the globules consisted of numerous individual peroxisomes, seemingly in direct contact with other peroxisomes and/or mitochondria. These peroxisomal clusters or aggregates were not observed in cells transiently expressing monomeric versions of APX. These findings indicate that the progressive, independent "zippering" of peroxisomes and pER is due to the post-sorting oligomerization of monomeric, cytosol-facing polypeptides that are integrally inserted into the membranes of "like" organelles. The dynamics of this process are discussed, especially with respect to the involvement of the microtubule cytoskeleton.     

Reconstructive management of contralateral breast cancer in patients who previously underwent unilateral breast reconstruction

When a patient who has had unilateral breast reconstruction presents with a new cancer on the opposite side, the reconstructive management of the second breast can be unclear. This study was performed to determine whether reconstruction of the second breast is oncologically reasonable and to evaluate the reconstructive options available to these patients.Patients who had mastectomy with unilateral breast reconstruction between 1988 and 1994 and who had a minimal follow-up of 5 years from the initial breast cancer were reviewed. Of 469 patients reviewed, 18 patients (4 percent) were identified who developed contralateral breast cancer. Mean age at the initial breast cancer presentation was 43 years (range, 26 to 57 years), and mean age at presentation with contralateral breast cancer was 48 years (range, 36 to 67). The mean interval between the initial and contralateral breast cancer presentations was 5 years (range, 1 to 10 years). Mean follow-up from the time of contralateral breast cancer was 5 years (range, 1 to 9 years). In most cases, contralateral breast cancer presented at an early stage (13 of 18 patients; 72 percent), and a shift to an earlier stage at presentation of the contralateral cancer was evident compared with the initial breast cancer. Of the 18 patients who developed contralateral breast cancer, 16 (89 percent) had no evidence of disease, one was alive with disease, and one died. Reconstructive management after the initial mastectomy included 16 transverse rectus abdominis myocutaneous flaps (seven free and nine pedicled), one latissimus dorsi myocutaneous flap with implant, and one superior gluteal free flap. Surgical management of the second breast after contralateral breast cancer included breast conservation in two patients, mastectomy without reconstruction in four, and mastectomy with reconstruction in 12. Reconstruction of the second breast included one free transverse rectus abdominis myocutaneous flap, three extended latissimus dorsi flaps, two latissimus dorsi myocutaneous flaps with implants, three implants alone, two Rubens flaps, and one superior gluteal free flap. No major complications were noted after the reconstruction of the second breast. The best symmetry was obtained when similar methods and tissues were used on both sides.The incidence of contralateral breast cancer after mastectomy and unilateral breast reconstruction is low. In most cases, contralateral breast cancer presents at an earlier stage compared with the initial breast cancer, and the prognosis is good. In patients who develop a contralateral breast cancer after mastectomy and unilateral breast reconstruction, the reconstruction of the second breast after mastectomy is oncologically reasonable and should be offered to provide optimal breast symmetry and a better quality of life. The best result is obtained when similar methods and tissues are used on both sides.     

Postoperative morphine requirements of free TRAM and DIEP flaps

In a review of the charts of 158 patients who had undergone breast reconstruction with free transverse rectus abdominis musculocutaneous (TRAM) or deep inferior epigastric perforator (DIEP) flaps and who were treated for postoperative pain with morphine administered by a patient-controlled analgesia pump, the total dose of morphine administered during hospitalization for the flap transfer was measured. Patients whose treatment was supplemented by other intravenous narcotics were excluded from the study. The mean amount of morphine per kilogram required by patients who had reconstruction with DIEP flaps (0.74 mg/kg, n = 26) was found to be significantly less than the amount required by patients who had reconstruction with TRAM flaps (1.65 mg/kg; n = 132; p < 0.001). DIEP flap patients also remained in the hospital less time (mean, 4.73 days) than did free TRAM flap patients (mean, 5.21 days; p = 0.026), but the difference was less than one full hospital day. It was concluded that the use of the DIEP flap does reduce the patient requirement for postoperative pain medication and therefore presumably reduces postoperative pain. It may also slightly shorten hospital stay.