Hyperbaric oxygen therapy in plastic surgery: a review article

The most important effects of hyperbaric oxygen (HBO), for the surgeon, are the stimulation of leukocyte microbial killing, the enhancement of fibroblast replication, and increased collagen formation and neovascularization of ischemic tissue. Preoperative hyperbaric oxygen induces neovascularization in tissue with radionecrosis. Refractory osteomyelitis and necrotizing fasciitis appear to respond to adjunctive hyperbaric oxygen. Crush injury and compartment syndrome appear to benefit through preservation of ATP in cell membranes, which limits edema. Hyperbaric oxygen in burn injury permits shorter hospital stays, a reduced number of surgeries, and less fluid replacement. Skin grafts and flaps are reported to take more completely and more rapidly. The same mechanisms may apply in ischemic problem wounds such as infected diabetic extremities. Contraindications and side effects are described. Hyperbaric oxygen will not heal normal wounds more rapidly but may, under certain circumstances, induce problem wounds to heal more like normal ones.     

四川省西部鱼类寄生粘孢子虫——1.粘体虫属六新种(粘孢子纲:双壳目)

本文报导四川省西部鱼类寄生粘孢子虫粘体虫属六新种,即异型粘体虫,新种Myxosoma disparis sp.nov.,四川粘体虫,新种Myxosoma sichuanensis sp.nov.,光唇粘体虫,新种Myxosoma acrossochilusi sp.nov.鳅粘体虫,新种Myxosoma nemachilusi sp.nov.斜囊粘体虫,新种Myxosoma obliqua sp.nov.,雅安粘体虫,新种Myxosoma yaanensis sp.nov.。     

关于苦马豆属学名的讨论

本文根据国内外豆科研究文献的考证,讨论了苦马豆属(Sphaerophysa DC.)及其近缘属的区别,重新确认了国产苦马豆属和苦马豆的学名。     

Temporal events of gypsy moth vitellogenesis and ovarian development

Abstract The vitellogenic period of gypsy moth ovarian development starts on day 3 of the pupal stage and continues through adulthood. During this period, rapid increases occur in follicle size, protein content, and wet weight of the ovary. Patency is observed on day 3 of the pupal stage.
Pre-vitellogenic follicles are formed in the last larval stadium. Newly formed follicles detach from the germarium on day 4, and increase rapidly to 140 per ovariole at the end of the last larval stadium. The pre-vitellogenic follicles are uniformly around 50 um in diameter. No vitellogenin is incorporated into the oocytes until the pupal stage.
Polyacrylamide gel electrophosesis (PAGE) in the presence of sodium dodecylsulphate (SDS) analysis of male and female haemolymph samples and vitellogenic ovaries demonstrates the presence of two female-specific subunits of vitellogenin of 180 kD and 160 kD. These proteins are detected only in haemolymph and ovarian extracts of vitellogenic females. The molecular weight of the native protein determined by size exclusion chromatography is approximately 400–420 kD.
A highly sensitive double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed to monitor the temporal changes in vitellogenin titre in haemolymph. Vitellogenin production starts on day 2 of the last larval stadium, reaching a maximum level by day 6 of the last larval stadium, and decreasing in the late pupal stage as vitellogenin was internalized into the oocytes. This is the first report of vitellogenin production occurring in the larval stage of a holometabolous insect. The fact that vitellogenin production and uptake occur during different stages of development in the gypsy moth, opens up some interesting questions concerning the underlying regulatory mechanisms controlling each process.     

Seasonal cycles of reserves in relation to reproduction inSebastes

Synopsis Seasonal cycles of reserve deposition and utilization in many fishes, amphibians and reptiles alleviate temporal mismatches of energy supply and demand. Utilization of reserves can be related to maintenance during periods of reduced food supply, to reproduction, particularly during periods of poor food availability, and to migration. Published data on the seasonal cycles of reserves and reproduction inSebastes suggest that reserves are important for maintenance during wintertime periods of low food availability. Unlike many other ectothermic vertebrates, some species ofSebastes deposit fat reserves at the same time as gametogenesis, a pattern consistent with the longevity and iteroparity evident in the genus. Other species ofSebastes have similar seasonal timing of fat cycles, but since reproduction takes place later in the year, the decline in reserves during winter coincides with the main period of reproductive activity. The significance of this is not clear. Interspecific differences in amounts of reserves may be related to geographical differences in the seasonality or abundance of food. Intraspecific variation in reserves, marked most strongly by allometry of reserves with regard to fish legth, bears further study, since it may link the proces of sexual maturation and the responses of repeat spawners to variability in food supply and other environmental factors.     

消炎痛及PGF_(2α)对在体培养人子宫内膜出血的影响

利用甾体激素撤退方法造成移植在地鼠颊囊内人子宫内膜出血的动物模型,研究消炎痛和PGF_(2a)对内膜出血的作用。结果表明,注射三种不同剂量消炎痛并不能完全抑制内膜出血,但对内膜出血时间有延缓作用。用两种不同剂量的PGF_(2a)采取缓慢释放给药方法,虽然地鼠在给药后外周血液中PGF_(2a)水平比给药前显著增高,但内膜出血并不出现在撤退甾体激素之前。结果提示,PGF_(2a)对内膜血管破裂无直接作用,而纤溶活性变化可能是触子宫内膜出血更直接的原因。     

蟾蜍卵母细胞的Na~+/H~+交换

应用pH选择性徽电极和普通檄电极测量了蟾蜍卵母细胞内的pH值(pHi)。当用含NH_4~+而不含HCO_3~-的溶液培灌卵母细胞时,pHi逐渐下降,在停止培灌后,pHi恢复到对照值。这个pHi恢复过程是一个H~+的主动转运,用胆碱离子取代培灌液中的Na~+可以抑制pHi的恢复,这种抑制作用是可逆的。伴随着细胞内pH值的恢复,细胞内Na~+活度(Na_1~+)呈现暂时性增加,而细胞内Cl-活度(Cl_1~+)不变或稍有增加。实验结果提示在蟾蜍卵母细胞膜上存在着Na~+/H~+的交换。     

Adaptation of Aquatic Microbial Communities to Quaternary Ammonium Compounds

The effects of long-chain (C₁₂ to C₁₈) quaternary ammonium compounds (QACs) on the density, heterotrophic activity, and biodegradation capabilities of heterotrophic bacteria were examined in situ in a lake ecosystem. Monoalkyl and dialkyl substituted QACs were tested over a range of concentrations (0.001 to 10 mg/liter) in both acute (3 h) and chronic (21 day) exposures. In general, none of the QACs tested had significant adverse effects on bacterial densities in either acute or chronic studies. However, significant decreases in bacterial heterotrophic activity were noted in acute studies at QAC concentrations from 0.1 to 10 mg/liter. Chronic exposure of lake microbial communities to a specific monoalkyl QAC resulted in an adaptive response and recovery of heterotrophic activity. No-observable-effect level in the adapted populations was >10 mg/liter. Chronic exposure also resulted in significant increases in the number and activity of bacteria capable of biodegrading the material. The increase in biodegradation capability was observed at low (microgram per liter) concentrations which are approximately the same as realistic environmental levels. In general, our studies indicated that exposure of lake microbial communities to QACs results in the development of adapted communities which are less sensitive to potential toxic effects and more active in the biodegradation of these materials.     

Cloning and expression of a tylosin resistance gene from a tylosin-producing strain of Streptomyces fradiae

Summary A gene conferring high-level resistance to tylosin in Streptomyces lividans and Streptomyces griseofuscus was cloned from a tylosin-producing strain of Streptomyces fradiae. The tylosin-resistance (Tyl^r) gene (tlrA) was isolated on five overlapping DNA fragments which contained a common 2.6 Kb KpnI fragment. The KpnI fragment contained all of the information required for the expression of the Tyl^r phenotype in S. lividans and S. griseofuscus. Southern hybridization indicated that the sequence conferring tylosin resistance was present on the same 5 kb SalI fragment in genomic DNA from S. fradiae and several tylosin-sensitive (Tyl^s) mutants. The cloned tlrA gene failed to restore tylosin resistance in two Tyl^s mutants derived by protoplast formation and regeneration, and it restored partial resistance in a Tyl^s mutant obtained by N-methyl-N-nitro-N-nitrosoguanidine (MNNG) mutagenesis. The tlrA gene conferred resistance to tylosin, carbomycin, niddamycin, vernamycin-B and, to some degree, lincomycin in S. griseofuscus, but it had no effect on sensitivity to streptomycin or spectinomycin, suggesting that the cloned gene is an MLS (macrolide, lincosamide, streptogramin-B)-resistance gene. Twenty-eight kb of S. fradiae DNA surrounding the tlrA gene was isolated from a genomic library in bacteriophage Charon 4. Introduction of these DNA sequence into S. fradiae mutants blocked at different steps in tylosin biosynthesis failed to restore tylosin production, suggesting that the cloned Tyl^r gene is not closely linked to tylosin biosynthetic genes.     

Microsomal flavonoid 3'-monooxygenase from maize seedlings

Identification of flavonoid 3′-monooxygenase establishes another reaction in the biosynthesis of flavonoid compounds in maize (Zea mays L.). The flavonoid 3′-hydroxylase was obtained as a microsomal enzyme preparation by buffer extraction of 5 day old maize seedlings and ultracentrifugation. Seedlings were exposed to light 24 hours prior to enzyme extraction. The extraction buffer required the addition of sucrose or glycerin and dithiothreitol to obtain an active hydroxylase that retained its activity on storage at −70°C. Enzymic activity required O₂ and NADPH, was optimum at pH 8.5 and 30°C, and could be inhibited 79% by carbon monoxide. Carbon monoxide inhibition could be reduced to 21% by irradiation of the samples with 450 nanometer light during incubation. Kaempferol, a flavonol; naringenin, a flavanone; and apigenin, a flavone, all served as substrates for the hydroxylase. Treatment of the microsomal enzyme preparation, previously reduced with sodium dithionite, with carbon monoxide gave a 455 nanometer absorption peak which disappeared on oxidation of the preparation with the formation of a 420 nanometer peak. These results suggest a cytochrome P-450 type monooxygenase enzyme. The concentration of cytochrome P-450 was 0.21 nanomoles per milligram protein. Identification of the monooxygenase provides further biochemical information about a biosynthetic sequence for which the genetics have been studied intensely.