Soft tissue adhesive composed of modified gelatin and polysaccharides

Although fibrin glue has been clinically used as a surgical adhesive, hemostatic agent, and sealant, it has the risk of virus infection because its components, fibrinogen and thrombin, are obtained from human blood. To circumvent this problem, we employed bioabsorbable gelatin and polysaccharides to prepare a safer hemostatic glue. Gelatin was modified with ethylenediamine using water-soluble carbodiimide to introduce additional amino groups into the original gelatin, while dextran and hydroxyethyl-starch were oxidized by sodium periodate to convert 1,2-hydroxyl groups into dialdehyde groups. Upon mixing of the two polymer components in aqueous solution, Schiff base was formed between the amino groups in the modified gelatin and the aldehyde groups in the modified polysaccharides, which thus resulted in intermolecular cross-linking and gel formation. The fastest gel formation took place within 2 s, and its bonding strength to porcine skin was about 225 gf cm(-2) when 20 wt% of an amino-gelatin (55% amino) and 10 wt% of aldehyde-HES (>84% dialdehyde) aqueous solutions were mixed. In contrast, the gelation time and bonding strength of fibrin glue was 5 s and 120 gf cm(-2), respectively.

Effects of light and darkness on cell deaths in damaged retinal ganglion cells of the carp retina

Effects of light and darkness on the apoptosis of retinal ganglion cells (RGCs) in young carp were measured by TUNEL method after transection of the optic nerve. Following the operation, the fish were kept under one of four regimens; constant darkness (DD), constant light (LL), 12 hr light and 12 hr dark (LD) and 3 hr of flickering light followed by 21 hr in the dark (FL). On day 3, the highest ratio of apoptotic RGCs was seen under conditions of DD, followed by LL, LD, and FL. On day 6, the percentages of apoptotic RGCs were lower under every experimental condition than what they had been earlier on day 3, but the same ranking order was maintained. Immunohistochemically it could be shown that phosphorylated ERKs were more intensively localized in FL rather than DD retinas. The results suggest that illumination regimens, and in particular cyclic diurnal light/dark changes, have an influence on the degree of apoptosis of damaged RGCs, and that inhibition of apoptosis is correlated with the higher expression of phosphorylated ERKs.

Detection and analysis of Bacillus subtilis growth with piezoelectric quartz crystal impedance based on starch hydrolysis

A piezoelectric quartz crystal (PQC) impedance method based on the alpha-amylase-catalyzed hydrolysis of starch present in a culture medium has been developed for in situ monitoring of the whole growth process of Bacillus subtilis and the variation in the activity of alpha-amylase during bacterial growth. An S-shaped response behavior was observed for Deltaf(0), and simultaneously inverse S-shaped responses were found for DeltaR(1) and DeltaL(1). The ratio of DeltaR(1) to Deltaf(0) or DeltaL(1) coincided well with that calculated from Martin's equations reflecting the solution density-viscosity effect, suggesting that the continuing change in liquid loading onto the PQC surface causes significant variation in Deltaf(0), DeltaR(1), and DeltaL(1). Bacterial growth equations were derived from the kinetics of the enzyme-catalyzed hydrolysis of starch, which fit well with the experimental responses of Deltaf(0), DeltaR(1), and DeltaL(1). Kinetic parameters of bacterial growth, including the asymptote (A), the maximum specific growth rate (microm), and the lag time (lambda), were obtained and were in good agreement with those obtained from the pour plate count method. The variation in the activity of alpha-amylase exhibited peak-type behavior with its maximum value at the later stage of the log phase. In addition, the influence of initial bacterial concentration was also investigated.

[A comparative study on chlorophyll content, chlorophyll fluorescence and diurnal course of leaf gas exchange of two ecotypes of banyan]

The morphological differences, chlorophyll contents, fluorescence and diurnal course of leaf gas exchange between terrestrial banyan and amphibious banyan were compared with pot culture. The amphibious banyan possesses well developed aerial and hydro-adventitious roots, and wider leaf with inclination of evolution toward mesophytic traits. The chlorophyll content of terrestrial banyan was higher than that of amphibious banyan. The diurnal course of leaf gas exchange indicated that net photosynthetic rate of terrestrial banyan was slightly higher than that of amphibious banyan grown in water, but much higher than that grown in soil. The amphibious banyan grown in water had the highest transpiration rate, the terrestrial banyan had a lower one, and the amphibious banyan grown in soil had the lowest. Linear regression analysis showed a positive correlation between net photosynthetic rate and stomatal conductance, implying that the stomatal conductance was dominant factor controlling the gas exchange. In this study, the term of intrinsic water use efficiency (net photosynthetic rate/stomatal conductance ratio, Intrinsic WUE) was applied to describe the photosynthesis and water properties, and the result showed that it was a more suitable measure compared to the usual WUE(net photosynthetic rate/transpiration rate). Among the three banyan plants examined, the amphibious banyan had the highest intrinsic WUE.

[Changes of type I collagen in the lungs of rats with hypoxic pulmonary hypertension]

The changes of type I collagen in the lung tissues of rats with hypoxic pulmonary hypertension (HPH) and its relationship to the mean pulmonary arterial pressure (mPAP) were investigated. The blood dynamic indexes of pulmonary circulation were measured by using Swan-Ganz. The distribution of type I collagen in pulmonary arteries, bronchi and plumonary interstitial was observed by using streptavidin peroxidase method (SP). The morphologic changes of small pulmonary arteries and the level of type I collagen were determined by image pattern analysis technique and gray scale scanning, respectively. The results showed, compared with the controls, mPAP of the hypoxic rats elevated (from 2.12 +/- 0.25 to 3.95 +/- 0.43 kPa, P < 0.01), their small pulmonary arteries, walls thickened (MT% from 16.35 +/- 2.64 to 35.83 +/- 3.55, MA% from 26.83 +/- 3.40 to 59.68 +/- 4.90, P < 0.01) and lumen narrowed. The distribution of type I collagen was mainly in the external layer of pulmonary arterial walls; the positive degrees of gray scale scanning increased and had a positive linear relationship to the mPAP and MT%. These findings suggest that the increase of type I collagen contents in pulmonary arteries is closely related to the development of HPH.

A highly ordered structure in V(D)J recombination cleavage complexes is facilitated by HMG1

Central to understanding the process of V(D)J recombination is appreciation of the protein-DNA complex which assembles on the recombination signal sequences (RSS). In addition to RAG1 and RAG2, the protein HMG1 is known to stimulate the efficiency of the cleavage reaction. Using electrophoretic mobility shift analysis we show that HMG1 stimulates the in vitro assembly of a stable complex with the RAG proteins on each RSS. We use UV crosslinking studies of this complex with azido-phenacyl derivatized probes to map the contact sites between the RAG proteins, HMG1 derivatives and the RSS. We find that the RAG proteins make contacts at the nonamer, heptamer and adjacent coding region. The HMG1 protein by itself appears to localize at the 3' side of the nonamer, but a cooperative complex with the RAG proteins is positioned at the 3' side of the heptamer and adjacent spacer in the 12RSS. In the complex with RAG proteins, HMG1 is positioned primarily in the spacer of the 23RSS. We suggest that bends introduced into these DNA substrates at specific locations by the RAG proteins and HMG1 may help distinguish the 12RSS from the 23RSS and may therefore play an important role in the coordinated reaction.

Isolation and identification of poly-alpha-(1-->4)-linked 3-O-methyl-D-mannopyranose from a hot-water extract of Mycobacterium vaccae

A polysaccharide around 3.6 kDa has been identified as the major carbohydrate moiety of a antineoplastic protein-polysaccharide complex (PS4A) obtained by boiling intact cells of Mycobacterium vaccae in water. 1H and 13C NMR spectra of this polysaccharide suggested it was a highly homogeneous polymer composed substantially of one monomer, probably an alpha-linked O-methylated mannose. Comparison of the COSY spectra of the original and acetylated polymer indicated that the glycosidic linkage and the methyl ether were interchangeable, at O-3 and O-4. Further study demonstrated that the benzyolated hydrolysate of the polymer was 1,2,4,6-tetra-O-benzoyl-3-O-methyl-beta-mannopyranose. The hydrolysate was 3-O-methyl-alpha, beta-mannopyranose and the polymer was therefore poly-alpha-(1-->4)-linked 3-O-methyl-D-mannopyranose. This conclusion was further confirmed with an authentic sample of the monomer, which had spectral data identical to those of the hydrolyzate and co-eluted from an ion-exchange HPLC with the major sugar in the hydrolysate.

Preparation of Shell-Core Cu(2)O-Cu Nanocomposite Particles and Cu Nanoparticles in a New Microemulsion System

Shell-core Cu(2)O-Cu nanocomposite particles and metal Cu nanoparticles are synthesized in a new microemulsion system which consists of saturated Cu(2+) salt aqueous solution dispersed in isopropanol and stabilized by polyvinylalcohol (PVA). The size of the composite particles and the thickness of the Cu(2)O shell layer can be controlled by the volume ratio of isopropanol to H(2)O (the ratio is defined as R). When R >/= 1000, it is available to obtain metal Cu nanoparticles. Copyright 1999 Academic Press.

A RAG1 and RAG2 tetramer complex is active in cleavage in V(D)J recombination

During V(D)J recombination two proteins, RAG1 and RAG2, assemble as a protein-DNA complex with the appropriate DNA targets containing recombination signal sequences (RSSs). The properties of this complex require a fairly elaborate set of protein-protein and protein-DNA contacts. Here we show that a purified derivative of RAG1, without DNA, exists predominantly as a homodimer. A RAG2 derivative alone has monomer, dimer, and larger forms. The coexpressed RAG1 and RAG2 proteins form a mixed tetramer in solution which contains two molecules of each protein. The same tetramer of RAG1 and RAG2 plus one DNA molecule is the form active in cleavage. Additionally, we show that both DNA products following cleavage can still be held together in a stable protein-DNA complex.

Separation of C/EBPalpha-mediated proliferation arrest and differentiation pathways

Cell proliferation and terminal differentiation are mutually exclusive in most cell lineages. The b-zip transcription factor CCAAT/enhancer-binding protein alpha (C/EBPalpha) induces proliferation arrest and differentiation in many cell types, suggesting that both activities are linked. Here we show that C/EBPalpha-mediated proliferation arrest and differentiation pathways can be separated by the E7 oncoprotein of the "high-risk" human papilloma virus 16. The E7 oncoprotein overrides C/EBPalpha-mediated cell cycle withdrawal without compromising the transactivation activity of C/EBPalpha or its ability to participate in differentiation. Uncoupling of both pathways depends on the casein kinase II site of the oncoprotein but not on its ability to neutralize pocket proteins or the cyclin-dependent kinase inhibitor protein p21. Our results suggest a bifurcation of C/EBPalpha-mediated proliferation arrest and differentiation pathways.

RAG1 and RAG2 cooperate in specific binding to the recombination signal sequence in vitro

An essential step in the development of the vertebrate immune system is the DNA level rearrangement of the antigen receptor genes. This process, termed "V(D)J recombination," begins with DNA cleavage at the appropriate sites mediated by the two proteins RAG1 and RAG2. We report here that the two proteins cooperate to bind DNA with significantly higher specificity than either protein alone. Gel purification of the triple complex is performed in the absence of any cross-linking agents. Both proteins remain present in the complex, and UV cross-linking using iodouridine-containing probes shows that RAG1 makes close contacts in both the heptamer and nonamer motifs. The two proteins are also shown to associate with each other in the absence of any DNA. These findings refine our understanding of the protein-DNA interactions that accompany cleavage at the recombination signals.

[Effect of tetrandrine on the collagen contents of lungs in rats with chronic hypoxia]

OBJECTIVE

To investigate the effect of tetrandrine (Tet) on the collagen contents of lung tissues in rats with chronic hypoxic pulmonary hypertension.

METHOD

Using colorimetric method after oxidized by chloramine T to determine hydroxyproline contents of lung tissues and extrapulmonary arteries, using Masson method, image pattern analysis technique and gray scale scanning to observe the changes of collagen distribution in extrapulmonary arteries and lung tissues in rats with hypoxia and the effect of treatment with Tet.

RESULT

Tet could remarkably reduce the mean pulmonary arterial pressure and pulmonary vascular resistance in rats with hypoxic pulmonary hypertension and could inhibit the increase of collagen contents in lung tissues and extrapulmonary arterial wall.

CONCLUSION

Tet may be used as one of the main drugs in the treatment of chronic hypoxic pulmonary hypertension due to its action of reducing mPAP and collagen contents.

[Effect of electro-acupuncture and transcutaneous electric nerve stimulation on experimental diabetes and its neuropathy]

In this paper, the experimental diabetic rats induced by streptozotocin (STZ, i.p. 50 mg/kg) were divided into three groups, electro-acupuncture (EA group, n = 8), transcutaneous electric nerve stimulation (TENS group, n = 8), at bilateral Shenshu and Zusanli points for 20 minutes once every 2-3 days for five weeks, and without any treatment (DM group, n = 6) respectively. As compared with the DM group, the increased plasma glucose levels was lowered significantly in EA group (P < 0.05) and slightly in TENS group (P > 0.05) by the end of the sixth week. And the symtoms of polyphagia, polydipsia and polyuria were attenuated in EA group. The motor nerve conduction velocity slowing was prevented or corrected after a course of four and six weeks treatment in EA and TENS group respectively. In the DM and TENS groups the pain threshold was lowered at 6-20 days after injection of STZ, but elevated in EA group, their differences were of significance (P < 0.05). In general, the efficiency of EA treatment on experimental diabetes and its neuropathy was better than that of TENS therapy.

Clinical studies on the mechanism for acupuncture stimulation of ovulation

Ovulatory dysfunction is commonly seen in gynecology clinic. It may cause infertility, amenia, functional uterine bleeding and a variety of complications. This research according to TCM theory records treating with acupuncture 34 patients suffering from ovulatory dysfunction. Changes in clinical symptoms and some relative targets are reported, plus findings in animal experiments. The effect of acupuncture in improving ovulation and the rationale are discussed. According to TCM theory concerning the generative and physiologic axis of women, this research involved the following points: Ganshu (UB 18), Shenshu (UB 23), Guanyuan (Ren 4), Zhongji (Ren 3), and Sanyinjiao (Sp 6). The reinforcement and reduction of acupuncture enables it to strengthen liver and kidney. Through the Chong and Ren channels it nourishes uterus to adjust the patient's axis function and recover ovulation. Treated on an average of 30 times, the patients' symptoms improved to varying degrees. The marked effective rate was 35.29%, the total effective rate being 82.35%. BBT, VS, CMS, and B ultrasonic picture all improved to some degree. The results also showed that acupuncture may adjust FSH, LH, and E2 in two directions and raise the progesterone level, bringing them to normal. The animal experiments confirmed this result. Results showed that acupuncture may adjust endocrine function of the generative and physiologic axis of women, thus stimulating ovulation. The results of this research will provide some scientific basis for treating and further studying this disorder.