Free transfer of expanded parascapular, latissimus dorsi, and expander "capsule" flap for coverage of large lower-extremity soft-tissue defect

The coverage of large soft-tissue defects usually requires a large flap transfer, especially in a combination and expanded form. However, some large soft-tissue defects still cannot be covered by such flaps. In this article, we present a case of a civil war injury in a patient from Afghanistan who had severe trauma to the right knee, lower thigh, and upper leg and a marked soft-tissue defect. This large soft-tissue defect was covered with a large combined free flap of the expanded parascapular and latissimus dorsi muscle, including a large retrograde hinge flap of the tissue expander capsule and a complementary skin graft. The defect was covered completely, and the final result was excellent.     

阿舍利大石片的生产方式与策略

阿舍利技术的两个核心要素在于剥取大石片以及制作手斧等定型化大型工具。目前,国内有关手斧工业的研究中,关注较多的是大型工具的加工与制作,而对于大石片生产的方式与策略则缺乏系统的研究和介绍。本文重点介绍和综述了目前国外发现和报道的大石片生产技术,并对每种技术的具体特点进行了分析和阐释。根据剥片复杂程度的不同,阿舍利大石片生产技术可细分为三类;第一类指砾石初级剥片技术,是利用原料的自然特征,选择合适台面和剥片角度进行单次剥片;第二类包括两面剥片技术、板状石核剥片技术和昆比哇技术,是在了解原料特征的基础上,对石核进行有计划的剥片,以便连续生产出多个大石片;第三类包括奇尔基技术、塔拜勒巴拉-塔奇恩基特技术和西维多利亚技术,是在较为复杂的剥片流程引导下,通过对石核的预制,获取具有相对稳定形态的大石片。在此基础上,初步分析了广西百色盆地发现的大型石核和大石片标本,探讨其在深入认识该地区石器工业面貌方面的作用和意义。     

Mutational analysis of delta antigen: effect on assembly and replication of hepatitis delta virus.

Hepatitis delta virus requires a helper function from hepatitis B virus for packaging, release, and infection of hepatocytes. The assembly of large delta antigen (HDAg) is mediated by copackaging with the small surface antigen of hepatitis B virus (HBsAg), and the assembly of small HDAg requires interactions with large HDAg. To examine the molecular mechanisms by which small HBsAg, large HDAg, and small HDAg interact, we have established a virion assembly system in COS7 cells by cotransfecting plasmids encoding the small HBsAg, the small HDAg, and large HDAg mutants. Results indicate that sequences within the C-terminal 19-amino-acid domain flanking the Cxxx isoprenylation motif are important for the assembly of large HDAg. In addition, a large HDAg mutant bearing extra sequences separating the C-terminal 19-amino-acid domain from the common regions of the small and large HDAgs is capable, like the wild-type large HDAg, of copackaging with small HBsAg. The ability of assembly is also demonstrated for a large HDAg mutant from which nuclear localization signals have been removed. Furthermore, a cryptic signal within the N-terminal 50 amino acid residues other than the putative N-terminal coiled-coil structure and a subdomain between amino acid residues 50 and 65 of the large HDAg are important for the assembly of small HDAg as well as the trans-dominant negative regulation of large HDAg in hepatitis delta virus replication.     

Identification of a Core Bacterial Community within the Large Intestine of the Horse

The horse has a rich and complex microbial community within its gastrointestinal tract that plays a central role in both health and disease. The horse receives much of its dietary energy through microbial hydrolysis and fermentation of fiber predominantly in the large intestine/hindgut. The presence of a possible core bacterial community in the equine large intestine was investigated in this study. Samples were taken from the terminal ileum and 7 regions of the large intestine from ten animals, DNA extracted and the V1-V2 regions of 16SrDNA 454-pyrosequenced. A specific group of OTUs clustered in all ileal samples and a distinct and different signature existed for the proximal regions of the large intestine and the distal regions. A core group of bacterial families were identified in all gut regions with clear differences shown between the ileum and the various large intestine regions. The core in the ileum accounted for 32% of all sequences and comprised of only seven OTUs of varying abundance; the core in the large intestine was much smaller (5-15% of all sequences) with a much larger number of OTUs present but in low abundance. The most abundant member of the core community in the ileum was Lactobacillaceae, in the proximal large intestine the Lachnospiraceae and in the distal large intestine the Prevotellaceae. In conclusion, the presence of a core bacterial community in the large intestine of the horse that is made up of many low abundance OTUs may explain in part the susceptibility of horses to digestive upset.     

Identification and Precipitation of the Polyribosomes in Chlamydomonas reinhardi Involved in the Synthesis of the Large Subunit of d-ribulose-1,5-bisphosphate Carboxylase

The size classes of polyribosomes involved in the synthesis of ribulose-1,5-bisphosphate carboxylase large subunit were determined by binding radioiodinated specific antibodies to polyribosomal preparations from Chlamydomonas reinhardi. Antibodies specific to the denatured large subunit and to the native enzyme bound primarily to small polyribosomes (N = two to five ribosomes). The binding of antibodies to small polyribosomes was unexpected since the large subunit is a large polypeptide (molecular weight 55,000) coded for by a corresponding large mRNA (12-14S). Control experiments showed that this unexpected pattern of antibody binding was not a result of messenger RNA degradation, "run-off" of ribosomes from polyribosomes, or adventitious binding of the completed enzyme to a selected class of polyribosomes. In addition, polyribosomes bearing nascent large subunit chains have been immunoprecipitated from small polyribosome fractions. A large RNA species that can direct the synthesis of large subunit in vitro was extracted from small polyribosomes.     

Structural basis for the inactivation of retinoblastoma tumor suppressor by SV40 large T antigen

Inactivation of the retinoblastoma (Rb) tumor suppressor by Simian virus 40 (SV40) large T antigen is one of the central features of tumorigenesis induced by SV40. Both the N-terminal J domain and the LxCxE motif of large T antigen are required for inactivation of Rb. The crystal structure of the N-terminal region (residues 7-117) of SV40 large T antigen bound to the pocket domain of Rb reveals that large T antigen contains a four-helix bundle, and residues from helices alpha2 and alpha4 and from a loop containing the LxCxE motif participate in the interactions with Rb. The two central helices and a connecting loop in large T antigen have structural similarities with the J domains of the molecular chaperones DnaJ and HDJ-1, suggesting that large T antigen may use a chaperone mechanism for its biological function. However, there are significant differences between large T antigen and the molecular chaperones in other regions and these differences are likely to provide the specificity needed for large T antigen to inactivate Rb.     

Thermoelectric Freezing for Attaching Nitrocellulose Blocks to the Microtome Stage

The routine production of large sections and of a few sections from a large number of blacks of tissue embedded in nitrocellulose often presents difficulties, large blocks often loosen if cemented to an intermediate carrier in the routine manner.     

Three-dimensional structure of the nickel-containing hydrogenase from Thiocapsa roseopersicina.

The three-dimensional structure of the nickel-containing hydrogenase from Thiocapsa roseopersicina has been determined at a resolution of 2 nm in the plane and 4 nm in the vertical direction by electron microscopy and computerized image processing on microcrystals of the enzyme. The enzyme forms a large ring-shaped complex containing six each of the large (62-kDa) and small (26-kDa) subunits. The complex is very open, with six well-separated dumbbell-shaped masses surrounding a large cylindrical hole. Each dumbbell is interpreted as consisting of one large and one small subunit.     

Assessing the functional importance of large‐bodied invertebrates in experimental headwater streams

Recent theoretical advances in food web ecology emphasize the importance of body size disparities among species for the structure, stability and functions of ecosystems. Experimental confirmations of the functional importance of large species, independent of their trophic position, are scarce. We specifically examine the multiple ecological roles of large invertebrates from two distinct trophic levels in headwater streams. We experimentally manipulated the presence of large predatory invertebrates (two Perlid stoneflies) or detritivores (a limnephilid caddisfly and a Pteronarcys stonefly) in a two‐by‐two design in stream channels open to immigration/emigration of smaller biota. We assessed treatment effects on the trophic structure of the benthic invertebrate community, dynamics of basal resources (benthic algae and leaf litter of cedar and alder), and stability of litter decomposition rates against an experimental pulse perturbation (fine sediment input). The presence of the large invertebrates was associated with a ten‐fold decrease in the biomass of invertebrate filterers whereas other trophic groups were unaffected by the large species. The biomass of benthic algae was lower and the rate of mass loss of alder litter was higher in channels lacking the large predators, thus revealing trophic cascades operating along both algal‐based and detritus‐based food chains. The large predators had no detectable effect on the decomposition of cedar whereas both cedar and alder disappeared faster in the presence of the large detritivores. Furthermore, the large predators and large detritivores interactively influenced the decomposition of the cedar–alder mixture through a litter diversity effect and the variability of the rate of alder decomposition after a pulse of fine sediment. Because the large invertebrates affected multiple ecosystem properties, and as their absence was not rapidly compensated for by small immigrant species, our findings support the notion that large species could be critically important in controlling ecosystem structure and functioning.     

Life history variation in a dobsonfly, Protohermes grandis (Megaloptera: Corydalidae): effects of prey availability and temperature

SUMMARY. 1. The life cycle of a predatory insect, Protohermes grandis (Megaloptera: Corydalidae), was compared in four streams in central Japan. The effects of annual temperature regime and prey availability on life history characteristics were also assessed.
2. The larval period was 2 years and small adults emerged in the Morito River, where summer water temperature was high and large prey scarce.
3. In the Nagura River, rich in large prey, the larval period was also 2 years in spite of slightly lower temperature, and the adult size was largest among the streams.
4. In Anado Fork with a low summer temperature, the larval development took 3 years, and large adults emerged. Large prey were abundant in this stream.
5. Seasonal abundance of large prey also affected the time large larvae left the stream to pupate. Larvae emigrated earlier in streams where the density of large prey sharply decreased after spring, than in streams where large prey were available throughout the year.     

Ultrastructural and histochemical study of previtellogenic oogenesis in the desert lizard Scincus mitranus (Squamata,Sauropsida)

The structure of the granulosa in reptilian sauropsids varies between groups. We investigated the follicle development in the desert lizard Scincus mitranus. In the germinal bed, oogonia, and primary oocytes were identified and found to be interspersed between the epithelial cells. Previtellogenesis was divided into three stages: early, transitional, and late previtellogenic stages. During the early previtellogenic stage (diplotene), the oocyte is invested by small epithelia cells that formed a complete single layer, which may be considered as a young follicle. The transitional previtellogenic stage was marked by proliferation and differentiation of the granulosa layer from a homogenous layer consisting of only small cells to a heterogeneous layer containing three cell types: small, intermediate, and large cells. The late previtellogenic stage was marked by high-synthetic activity of large cells and the initiation of cytoplasmic bridges between large granulosa cells and the oocyte. Small cells were the only type of granulosa cells that underwent division. Thus, these cells may be stem cells for the granulosa cell population and may develop into intermediate and subsequently large cells. The intermediate cells may be precursors of large cells, as suggested by their ultrastructure. The ultrastructure of the large granulosa was indicative of their high synthetic activity. Histochemical analysis indicated the presence of cholesterol and phospholipids in the cytoplasm of large cells, the zona pellucida, among the microvilli, in the bridges region, and in the cortical region of the oocyte cytoplasm. These materials may be transferred from large cells into the oocyte through cytoplasmic bridges and provide nutritive function to large cells rather than functioning in steroidogenesis or vitellogenesis.     

Differential phosphorylation of cytoplasmic and nuclear variants of simian virus 40 large T antigen encoded by simian virus 40-adenovirus 7 hybrid viruses.

The phosphorylation patterns of cytoplasmic and nuclear forms of simian virus 40 large T antigen encoded by simian virus 40-adenovirus 7 hybrid viruses were analyzed by two-dimensional peptide mapping. The PARA(cT) mutant which encodes a large T antigen defective for nuclear transport was used as source for cytoplasmic large T antigen. The data suggest that the large T antigen is phosphorylated in a sequential manner at a subset of sites in the cytoplasm and at additional sites in the nucleus.     

Patterns of wing size variation in seeds of the lily Cardiocrinum cordatum (Liliaceae)

We examined the patterns of variation in wing-loading and its related characteristics in Cardiocrinum cordatum to clarify the factors that determine the variation in seed dispersal ability in this species. The square root of wing-loading of a seed of a plant was not significantly correlated with basal stem diameter of a plant, indicating that large plants did not necessarily produce seeds with high dispersal ability. This result was inconsistent with the hypothesis that large plants produce seeds with high dispersal ability to avoid high mortality of seeds and seedlings in the vicinity of the parents. On the other hand, the square root of wing-loading of a seed of a fruit was negatively dependent on seed number of a fruit. Thus, many-seeded fruits produced seeds with high dispersal ability. This was because the projected surface area per seed was large in large fruits and large fruits contained large numbers of seeds. The cost per seed of producing fruit structures was small for many-seeded fruits. Thus, high dispersal ability of seeds in many-seeded fruits may be a result of an effective resource allocation pattern in which a high proportion of resources are allocated to those many-seeded fruits, enabling seeds to develop large wings and thus reducing the structural cost of fruits per seed.     

Isolation and properties of two classes of low-density vesicles from Saccharomyces cerevisiae.

A mixture of small (0.43-mum diameter) and large (0.62-mum diameter) low-density vesicles from spheroplasts of Saccharomyces cerevisiae was fractionated by rate centrifugation in a gradient of 0 to 8% (wt/vol) Ficoll to yield fractions rich (90 to 95%) in small or large vesicles. The large, but not small, vesicles swelled when diluted into mannitol solutions containing less than 0.4 M mannitol. The pH-electrophoretic mobility curve of the large vesicles showed that they are probably enclosed in a phospholipid-protein membrane. The dyes neutral red and toluidine blue, accumulated into large vesicles by intact cells and spheroplasts, were largely lost from large vesicles when these were separated from stained spheroplasts. Sudan black III stained small and large vesicles, both classes of vesicle retaining the stain on separation. Fractions rich in large vesicles contained proportionately more phospholipid and less free sterols, diacylglycerols, and free fatty acids compared with those enriched in small vesicles. The two classes of vesicles contained about the same proportions of esterified sterols and triacylglycerols. The free fatty acids in both small and large vesicles were free from unsaturated fatty-acyl residues; diacylglycerols and triacylglycerols contained appreciable proportions of unsaturated fatty-acyl residues. Small vesicles were richer in lipase activity, whereas the larger vesicles contained greater beta-glucanase and alpha-mannosidase activities. Phospholipase activity could not be detected in any of the fractions.     

Thermoelectric Freezing for Attaching Nitrocellulose Blocks to the Microtome Stage

The routine production of large sections and of a few sections from a large number of blacks of tissue embedded in nitrocellulose often presents difficulties, large blocks often loosen if cemented to an intermediate carrier in the routine manner.     

Personnel available in Histochemistry

The routine production of large sections and of a few sections from a large number of blacks of tissue embedded in nitrocellulose often presents difficulties, large blocks often loosen if cemented to an intermediate carrier in the routine manner.     

The DnaJ domain of polyomavirus large T antigen is required to regulate Rb family tumor suppressor function.

Tumor suppressors of the retinoblastoma susceptibility gene family regulate cell growth and differentiation. Polyomavirus large T antigens (large T) bind Rb family members and block their function. Mutations of large T sequences conserved with the DnaJ family affect large T binding to a cellular DnaK, heat shock protein 70. The same mutations abolish large T activation of E2F-containing promoters and Rb binding-dependent large T activation of cell cycle progression. Cotransfection of a cellular DnaJ domain blocks wild-type large T action, showing that the connection between the chaperone system and tumor suppressors is direct. Although they are inactive in assays dependent on Rb family binding, mutants in the J region retain the ability to associate with pRb, p107, and p130. This suggests that binding of Rb family members by large T is not sufficient for their inactivation and that a functional J domain is required as well. This work connects the DnaJ and DnaK molecular chaperones to regulation of tumor suppressors by polyomavirus large T.     

Removal of serine phosphates from simian virus 40 large T antigen increases its ability to stimulate DNA replication in vitro but has no effect on ATPase and DNA binding.

The effect of phosphorylation on the ability of simian virus 40 large T antigen to stimulate DNA synthesis in vitro was tested. Treatment of affinity-purified large T antigen with calf intestinal alkaline phosphatase resulted in the removal of 70 to 80% of the phosphate residues. Only serine-bound phosphate residues were affected. Phosphatase-treated large T antigen stimulated in vitro DNA synthesis fourfold over the untreated control. The stimulation was strongest at early times of DNA replication. At later times, DNA replication proceeded at equal rates with dephosphorylated and untreated large T antigen. The ATPase activity of large T antigen was not affected by phosphatase treatment. The origin-binding activity of large T antigen was tested over a wide range of large T antigen to DNA ratios, including DNA excess, and in the presence and absence of carrier DNA. Under no condition was an effect of dephosphorylation of large T antigen on its DNA-binding activity observed. These findings might indicate that phosphorylation at serine residues modulates the interaction of large T antigen with cellular factors. During DNA synthesis large T antigen was substantially rephosphorylated by kinases in the HeLa cell extract. As shown by two-dimensional peptide mapping, this phosphorylation occurred at all known in vivo sites. No phosphatase and protease activities were detectable in the HeLa cell extract.     

Synthesis and assembly of large subunits into ribulose bisphosphate carboxylase/oxygenase in chloroplast extracts

We have developed a new system for the in vitro synthesis of large subunits and their assembly into ribulose bisphosphate carboxylase oxygenase (Rubisco) holoenzyme in extracts of higher plant chloroplasts. This differs from previously described Rubisco assembly systems because the translation of the large subunits occurs in chloroplast extracts as opposed to isolated intact chloroplasts, and the subsequent assembly of large subunits into holoenzyme is completely dependent upon added small subunits. Amino acid incorporation in this system displayed the characteristics previously reported for chloroplast-based translation systems. Incorporation was sensitive to chloramphenicol or RNase but resistant to cycloheximide, required magnesium, and was stimulated by nucleotides. The primary product of this system was the large subunit of Rubisco. However, several lower molecular weight polypeptides were formed. These were structurally related to the Rubisco large subunit. The initiation inhibitor aurintricarboxylic acid (ATA) decreased the amount of lower molecular weight products accumulated. The accumulation of completed large subunits was only marginally reduced in the presence of ATA. The incorporation of newly synthesized large subunits into Rubisco holoenzyme occurred under conditions previously identified as optimal for the assembly of in organello-synthesized large subunits and required the addition of purified small subunits.     

Studies on the assembly of large subunits of ribulose bisphosphate carboxylase in isolated pea chloroplasts

Ribulose bisphosphate carboxylase consists of cytoplasmically synthesized "small" subunits and chloroplast-synthesized "large" subunits. Large subunits of ribulose bisphosphate carboxylase synthesized in vivo or in organello can be recovered from intact chloroplasts in the form of two different complexes with sedimentation coefficients of 7S and 29S. About one-third to one-half of the large subunits synthesized in isolated chloroplasts are found in the 7S complex, the remainder being found in the 29S complex. Upon prolonged illumination of the chloroplasts, newly synthesized large subunits accumulate in the 18S ribulose bisphosphate carboxylase molecule and disappear from both the 7S and the 29S large subunit complexes. The 29S complex undergoes an in vitro dissociation reaction and is not as stable as ribulose bisphosphate carboxylase. The data indicate that (a) the 7S large subunit complex is a chloroplast product, the (b) the 29S large subunit complex is labeled in vivo, that (c) each of these two complexes can account quantitatively for all the large subunits assembled into RuBPCase in organello, and that (d) excess large subunits are degraded in chloroplasts.