Structure-refinement program for disordered carbons

An automated structure-refinement program has been developed for X-ray powder diffraction data collected on disordered carbons. The program minimizes the difference between the observed and calculated diffraction profiles in a least-squares sense by optimizing model parameters analogously to the popular Rietveld refinement method. Unlike the Rietveld method, which is designed for crystalline materials, this program allows the quantification of the finite size, strain and disorder present in disordered carbon fibers and cokes. For example, the structural model used includes the probability of a random translation parallel to adjacent carbon layers as a refinable parameter describing turbostratic disorder. Other parameters are used to describe finite size, fluctuations in the spacing between adjacent layers, average lattice constants, background and other important quantities. The structural model, combined with the refinement program, acceptably describes the diffraction patterns from disordered carbons such as pitch heated near 823 K, cokes, fibers, heat-treated cokes and synthetic graphite.

Antioxidant properties of fractions and polyphenol constituents from green, oolong and black teas

Green, oolong and black teas were extracted with water, and then the water extracts were extracted separately with three types of solvent, chloroform, ethyl acetate and butanol, to obtain eight fractions. Major flavanol was extracted by EtOAc, while most of the alkaloid was in the chloroform fraction. Thearubigin was greatest in the butanol fraction, and most of the amino acid remained in the water fraction. All fractions were systematically analyzed by UV spectrophotometer and reverse phase HPLC for those important components existing in green tea, oolong tea, and black tea. The pure compounds of (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), free theaflavin, theaflavin monogallate-A, theaflavin monogallate-B, and theaflavin digallate were separated by LH-20 chromatography and reverse phase HPLC. All fractions and pure compounds were assayed for antioxidant activity and lipoxygenase inhibition activity. Flavanol showed very strong antioxidant activity and lipoxygenase inhibition.

The risk of osteoarthritis with running and aging: a 5-year longitudinal study

Our purpose was to determine the 5-year longitudinal effects of running and aging on the development of radiographic and clinical osteoarthritis (OA) of the knees, hands and lumbar spine. Thirty-five running subjects and 38 controls, with a mean age of 63 years, were matched for age (+/- 2 years), years of education, and occupation; 33 matched pairs were constructed. All subjects underwent rheumatologic examination, completed questionnaires, and had radiographs taken of the hands, lateral lumbar spine, and knees in 1984 and in 1989. Five year radiographic results for both the runner and control groups showed OA progression for the knees, hands, and lumbar spine. In 1989, 10 (13%) of the 73 subjects fit American College of Rheumatology (ACR) criteria for clinical OA of the hand, and 9 subjects (12%) fit ACR criteria for OA of the knee. In summary, running did not accelerate the development of radiographic or clinical OA of the knees, but with aging, 13% of all subjects developed OA of the hands and 12% of all subjects developed OA of the knees.

Molecular mimicry of hepatitis B surface antigen by an anti-idiotype-derived synthetic peptide

Monoclonal antibody 2F10 is an "internal-image" anti-idiotype (anti-id) antibody capable of mimicking the group-specific "a" determinant of human hepatitis B surface antigen (HBsAg). By mRNA sequencing and computer-assisted molecular modeling of monoclonal antibody 2F10, we identified a 15-amino acid region of the heavy-chain hypervariable region that has partial residue homology with sequences of the "a" determinant epitopes of HBsAg. We have established that a linear 15-mer peptide from a contiguous region on the anti-id antibody can (i) generate anti-HBsAg-specific antibodies when injected into mice, (ii) prime murine lymph node cells for in vitro HBsAg-specific T-cell proliferative responses, and (iii) stimulate in vitro human CD4+ T cells that were primed in vivo to HBsAg by natural infection with hepatitis B virus or vaccination with a commercially available HBsAg vaccine. Significantly, this peptide could also stimulate CD4+ T cells of human hepatitis B virus carriers. We conclude that a 15-mer peptide derived from the anti-id sequence can duplicate the B- and T-cell stimulatory activity of the intact anti-id antibody and the antigen that is mimicked, HBsAg.

The effect of platelet activating factor on different phases of murine in vitro fertilization

PURPOSE

Our purpose was to examine the effect of platelet activating factor (PAF) in different phases of mouse in vitro fertilization and optimal parameters that would enhance the fertilization rate.

DESIGN AND SETTINGS

Various PAF concentrations (10(-7) to 10(-5) M) were selected to investigate its effect on three phases of mouse in vitro fertilization (i.e., sperm capacitation, sperm/oocyte coincubation, and preimplantation embryo growth) in three experimental groups: (I) with PAF treatment in the first phase, (II) with PAF treatment adopted in the first and second phases, and (III) with PAF treatment implemented in all three phases.

RESULTS

The improvement of the fertilization rate in PAF treatment groups over the control group ranges from 6.5 to 19.0% (P < 0.05-P < 0.001). The highest enhancement of fertilization rate was achieved under the condition of PAF treatment (10(-6) M) through sperm capacitation and sperm/oocyte coincubation phases.

CONCLUSION

The PAF concentration of 10(-6) M in sperm capacitation and sperm/oocyte coincubation yielded the greatest improvement in fertilization. However, continuing PAF treatment after sperm/oocyte coincubation had no beneficial effect on fertilization and preimplantation development.

Antioxidative effect of polyphenol extract prepared from various Chinese teas

METHODS. Twelve different types of Chinese teas, including green, semifermented, and black tea, were studied for their antioxidant activities and active components. Compositions of (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, and gallic acid were identified by fast atom bombardment-mass spectrometry and high-performance liquid chromatography-mass spectrometry and quantified by high-performance liquid chromatography. Antioxidant activities in lard were measured by the Rancimat method. RESULTS. The results showed that both yields of polyphenol extract and antioxidant activities varied with different tea processing methods. It was found that (-)-epigallocatechin gallate, (-)-epigallocatechin, and (-)-epicatechin gallate inhibited soybean lipoxygenase at the IC50 values ranging from 10 to 20 microM.

Characterization of a 54-nucleotide gap region in the 28S rRNA gene of Schistosoma mansoni

We have analyzed 572 bp in the 28S rDNA of the human blood fluke Schistosoma mansoni which correspond to expansion segment 5 of domain IV as defined by Clark et al. for the Xenopus laevis 28S rRNA. S1 nuclease mapping and primer extension analysis comparing this region with the mature 28S rRNA indicate that there are 54 nucleotides present in the 28S rDNA which are absent from the mature rRNA. This defines a gap that creates two 28S rRNA subunits (28S alpha and 28S beta). Comparison of the S. mansoni sequence with rDNAs of other organisms which contain gaps in their 28S rRNA shows that the overall features are conserved except that the S. mansoni gap is less A + T-rich. The conserved features include: (1) the location of the gap within the 28S rRNA; (2) the predicted secondary structure of the gap, containing a stem-loop with a UAAU sequence within the loop; and (3) a conserved CGAAAGGG on the 3' side of the gap.

[Anti-inflammatory effect of aconitines]

Aconitines are the total alkaloids isolated from the main root of Aconitum carmichaeli. They have marked suppressive effect on the swelling of rat's hind paw induced by injections of fresh egg protein, carrageenin, histamine and 5-HT, on the mouse's ear oedema induced by bimethylphenyl, on the exudate and proliferation of granulation tissue of granuloma pouch induced by croton oil, on the leukocyte migration and on the contents of PGE in the exudate of the swelling hind paw induced by injecting carrageenin. Aconitines have been found useful in inhibiting significantly such immune inflammations as reversible passive Arthus reaction, rat's delayed skin hypersensitivity and adjuvant arthritis. They have also a noticeable analgesic effect.

Effects of activating spinal alpha-adrenoreceptors on sympathetic nerve activity in the rat

The effects of several alpha-adrenoreceptor agonists and antagonists administered intrathecally at T10 level on renal sympathetic nerve activity (RSNA) were examined, in chloralose-urethane anaesthetised rats. Intrathecal noradrenaline (NA, 0.5-500 micrograms) produced one of 3 responses depending on dose, an inhibition of RSNA at low doses, an excitation of RSNA at high doses, or a biphasic effect. Intrathecal adrenaline (5-200 micrograms) was inhibitory in the main but some doses elicited poorly repeatable brief excitation followed by prolonged inhibition. Intrathecal methoxamine (ME; 2.5 ng-25 micrograms) caused a dose-dependent increase in RSNA (mean maximum response 27 +/- 0.5%). The excitatory effects of NA and ME were blocked (72% +/- 12%) by pretreatment with intrathecal prazosin (PRA, 20-200 ng) but not by yohimbine (YOH, 200 ng). Intrathecal guanabenz (GUA 3-15 micrograms) caused a dose-dependent inhibitory effect on RSNA (mean maximum 32% +/- 5%). The inhibitory effects of NA, adrenaline and GUA were blocked by pretreatment with intrathecal YOH (200 ng-2 micrograms). Intrathecal PRA (200 ng) had no effect on the inhibitory effects of NA and GUA. Intravenous administration of each of the adrenoreceptor agonists (apart from adrenaline), at similar doses to those given intrathecally, in most cases had no significant effect on RSNA; in a few cases the opposite effects to those produced by intrathecal administration were seen.