Prediction of presence and absence of two- and three-amino-acid sequences of human monoamine oxidase from its amino acid composition according to the random mechanism

Three probabilistic procedures are used to analyse the human monoamine oxidase B (MAO-B). (1) Each kind of two-, three- and multi-amino-acid sequences is counted along MAO-B from one terminal to the other and their frequencies and probabilities are calculated. (2) The amino-acid sequences in MAO-B are compared with the theoretical amino-acid sequences and the present or absent theoretical amino-acid sequences in MAO-B are determined. (3) The random principle is used to predict the frequencies of presence and absence of amino-acid sequences in MAO-B from its amino acid composition and the comparison is made between predicted and counted frequencies. The results show the random principle can predict the presence of 99 two-amino-acid sequences in MAO-B and the absence of 38 and 7506 kinds of theoretical two- and three-amino-acid sequences from MAO-B.

Intraneuronal N-acetylaspartate supplies acetyl groups for myelin lipid synthesis: evidence for myelin-associated aspartoacylase

Despite its growing use as a radiological indicator of neuronal viability, the biological function of N-acetylaspartate (NAA) has remained elusive. This is due in part to its unusual metabolic compartmentalization wherein the synthetic enzyme occurs in neuronal mitochondria whereas the principal metabolizing enzyme, N-acetyl-L-aspartate amidohydrolase (aspartoacylase), is located primarily in white matter elements. This study demonstrates that within white matter, aspartoacylase is an integral component of the myelin sheath where it is ideally situated to produce acetyl groups for synthesis of myelin lipids. That it functions in this manner is suggested by the fact that myelin lipids of the rat optic system are well labeled following intraocular injection of [14C-acetyl]NAA. This is attributed to uptake of radiolabeled NAA by retinal ganglion cells followed by axonal transport and transaxonal transfer of NAA into myelin, a membrane previously shown to contain many lipid synthesizing enzymes. This study identifies a group of myelin lipids that are so labeled by neuronal [14C]NAA, and demonstrates a different labeling pattern from that produced by neuronal [14C]acetate. High performance liquid chromatographic analysis of the deproteinated soluble materials from the optic system following intraocular injection of [14C]NAA revealed only the latter substance and no radiolabeled acetate, suggesting little or no hydrolysis of NAA within mature neurons of the optic system. These results suggest a rationale for the unusual compartmentalization of NAA metabolism and point to NAA as a neuronal constituent that is essential for the formation and/or maintenance of myelin. The relevance of these findings to Canavan disease is discussed.

Tetrahydrobiopterin levels regulate endothelial cell proliferation

Vascular abnormalities, including altered angiogenesis, are major factors contributing to the morbidity and mortality of diabetes. We hypothesized that impaired angiogenesis in diabetes results from decreased tetrahydrobiopterin (BH4)-dependent synthesis of nitric oxide (NO) by endothelial cells (EC). To test this hypothesis, we utilized EC from spontaneously diabetic BB (BBd) and nondiabetes-prone BB (BBn) rats to investigate the link between BH4 and EC proliferation. There were significant decreases in the proliferation rate and expression of proliferating cell nuclear antigen in BBd versus BBn EC, with no evidence of apoptosis in either group. Sepiapterin (a precursor of BH4 via the salvage pathway) increased BH4 synthesis and enhanced proliferation of BBd EC. The stimulating effect of sepiapterin on EC proliferation was attenuated by NG-monomethyl-L-arginine, a NO synthase inhibitor. Reducing BH4 concentrations in BBn EC caused a decrease in proliferation, which was attenuated by a long-acting NO donor. Our results suggest that BH4 levels regulate proliferation of normal EC and that a BH4 deficiency impairs NO-dependent proliferation of BBd EC.

Elevated arginase I expression in rat aortic smooth muscle cells increases cell proliferation

Arginase, which exists as the isoforms arginase I and II, catalyzes the hydrolysis of arginine to ornithine and urea. Ornithine is the principal precursor for production of polyamines, which are required for cell proliferation. Rat aortic smooth muscle cells (RASMC) contain constitutive arginase I, and arginase inhibitors cause inhibition of cell proliferation. The objective of this study was to determine whether the elevated expression of arginase I in RASMC causes increased cell proliferation. RASMC were stably transfected with either rat arginase I cDNA or a beta-galactosidase control expression plasmid. Western blots and arginase enzymatic assays revealed high-level expression of cytosolic arginase I in arginase I-transfected RASMC. Moreover, this observation was associated with the increased production of urea and polyamines and higher rates of RASMC proliferation. The two selective inhibitors of arginase, N(G)-hydroxy-l-arginine and S-(2-boronoethyl)-l-cysteine, inhibited arginase and decreased the production of urea and polyamines in arginase I-transfected RASMC, all of which were associated with the inhibition of cell proliferation. This study demonstrates that elevated arginase I expression increases RASMC proliferation by mechanisms involving increased production of polyamines. These observations suggest that arginase I plays a potentially important role in controlling RASMC proliferation.

Ornithine aminotransferase messenger RNA expression and enzymatic activity in fetal porcine intestine

In most neonatal animals, the small intestinal epithelium is responsible for endogenous arginine production. The ability of neonatal enterocytes to synthesize arginine immediately after birth suggests that the enzymes involved are present prenatally. Pyrroline-5-carboxylate is the common intermediate in the intestinal pathways for the synthesis of citrulline and arginine from both glutamine and proline and is interconverted into ornithine by ornithine aminotransferase (OAT). In this study, OAT enzymatic activity and mRNA expression in the intestine of fetal pigs from 30 to 110 d of gestation were determined. Enzymatic activity (nanomoles per minute per milligram of protein) peaked at d 45 of gestation and increased again between d 60 and 110 of gestation. At 30 and 35 d of gestation, OAT mRNA expression was detected throughout the mucosal epithelium of the small intestine. Throughout the remainder of gestation, OAT expression was notably higher in the villus epithelium than in the crypt epithelium. The presence of OAT in the small intestinal epithelium throughout gestation suggests that the porcine small intestine is capable of interconverting ornithine and pyrroline-5-carboxylate during fetal development. This capability may be important for synthesis of arginine, proline, ornithine, and polyamines for development and metabolic activity of the intestine during gestation or for somatic growth of the fetus.

Distinct effect of orphanin FQ in nucleus raphe magnus and nucleus reticularis gigantocellularis on the rat tail flick reflex

The aim of the present study is to investigate the effects of orphanin FQ (OFQ) microinjected into the nucleus raphe magnus (NRM) and the nucleus reticularis gigantocellularis (NGC) on pain modulation. The tail-flick latency (TFL) was used as a behavioral index of nociceptive responsiveness. The result showed microinjection of OFQ into the NRM significantly increased the TFL, whereas microinjection of OFQ into the NGC decreased the TFL, suggesting the analgesic effect of OFQ in the NRM and the hyperalgesic effect of OFQ in the NGC. As there are three classes of putative pain modulating neurons in the rostral ventromedial medulla (RVM), the hyperalgesic or analgesic effect of OFQ in the RVM might depend upon the different class of the neurons being acted.

Capsaicin responses in heat-sensitive and heat-insensitive A-fiber nociceptors

The recently cloned vanilloid receptor (VR1) is postulated to account for heat and capsaicin sensitivity in unmyelinated afferents. We sought to determine whether heat and capsaicin sensitivity also coexist in myelinated nociceptive afferents. Action potential (AP) activity was recorded from single A-fiber nociceptors that innervated the hairy skin in monkey. Before intradermal injection of capsaicin (10 microg/10 microl) into the receptive field, nociceptors were classified as heat-sensitive (threshold, </=53 degrees C, 1 sec) or heat-insensitive afferents and as mechanically sensitive (von Frey threshold, <6 bar) or mechanically insensitive afferents. All heat-sensitive afferents (n = 16) were insensitive to mechanical stimuli but responded to the intradermal injection of capsaicin (69 +/- 7 APs in 10 min). Responsiveness to mechanical stimuli, thermal stimuli, and capsaicin varied in their receptive fields; the majority of receptive field sites (24 of 36) were responsive to only one or two stimulus modalities, whereas only eight sites responded to all three modalities. For most heat-insensitive afferents, the activity induced by the capsaicin injection did not exceed the activity induced by needle insertion alone. However, the largest response to capsaicin (314 +/- 98 APs in 10 min) was observed for five afferents that were insensitive to heat as well as mechanical stimuli and therefore may be classified as cutaneous chemoreceptors. These results suggest that A-fiber nociceptors play a role in the pain and hyperalgesia associated with capsaicin injection. Our finding that a subgroup of capsaicin-sensitive A-fiber nociceptors are insensitive to heat predicts the existence of heat-insensitive capsaicin receptors.

Peroxidase self-inactivation in prostaglandin H synthase-1 pretreated with cyclooxygenase inhibitors or substituted with mangano protoporphyrin IX

Self-inactivation imposes an upper limit on bioactive prostanoid synthesis by prostaglandin H synthase (PGHS). Inactivation of PGHS peroxidase activity has been found to begin with Intermediate II, which contains a tyrosyl radical. The structure of this radical is altered by cyclooxygenase inhibitors, such as indomethacin and flurbiprofen, and by replacement of heme by manganese protoporphyrin IX (forming MnPGHS-1). Peroxidase self-inactivation in inhibitor-treated PGHS-1 and MnPGHS-1 was characterized by stopped-flow spectroscopic techniques and by chromatographic and mass spectrometric analysis of the metalloporphyrin. The rate of peroxidase inactivation was about 0.3 s(-)1 in inhibitor-treated PGHS-1 and much slower in MnPGHS-1 (0.05 s(-)1); as with PGHS-1 itself, the peroxidase inactivation rates were independent of peroxide concentration and structure, consistent with an inactivation process beginning with Intermediate II. The changes in metalloporphyrin absorbance spectra during inactivation of inhibitor-treated PGHS-1 were similar to those observed with PGHS-1 but were rather distinct in MnPGHS-1; the kinetics of the spectral transition from Intermediate II to the next species were comparable to the inactivation kinetics in each case. In contrast to the situation with PGHS-1 itself, significant amounts of heme degradation occurred during inactivation of inhibitor-treated PGHS-1, producing iron chlorin and heme-protein adduct species. Structural perturbations at the peroxidase site (MnPGHS-1) or at the cyclooxygenase site (inhibitor-treated PGHS-1) thus can influence markedly the kinetics and the chemistry of PGHS-1 peroxidase inactivation.

[Subtotal laryngectomy reconstructed by platysma myocutaneous flaps]

OBJECTIVE

To study the feasibility, surgical techniques and the results of laryngeal function preservation during subtotal laryngectomy in laryngeal carcinoma.

METHODS

A retrospective review was made of 13 patients treated by subtotal laryngectomy and laryngeal reconstruction from 1991 to 1996. Eleven patients were male and 2 were female. The age ranged from 46 to 72 years, with a mean of 53.25. All cases were of stage IV. The essence of this operation is to reconstruct the new larynx with two platysma myocutaneous flaps following subtotal laryngectomy.

RESULTS

The success rate of voice rehabilitation was 100%. Among them, the acceptability rating scores in 11 cases were 7 and the intelligibility scores ranged from 95% to 98%. The other two cases had acceptability 5 and intelligibility form 90% to 94%. The three-year survival rate was 84.6% (11/13), 5-year survival rate was 76.9% (10/13).

CONCLUSION

This form of laryngeal reconstruction in subtotal laryngectomy is helpful to restore laryngeal function and decrease the rate of total laryngectomy. The procedure is easy, safe and applicable to patients treated by subtotal laryngectomy.

Effects of acupuncture on humoral immunologic function and trace elements in 20 cases of Behcet's disease

Acupuncture therapy could normalize both increased light chain K value of IgM and lowered trace element Zn content in patients with Behcet's disease with statistically significant differences, suggesting that acupuncture therapy can elevate humoral immunologic function and improve metabolism of the trace element in these patients.

[A study on DPPH free-radical scavengers from Xylaria nigripes]

The DPPH free-radical scavengers from the fungal Chinese medicine 'Wulingshen' (Xylaria nigripes) were studied. After separation using silica gel colunm chromatography, MPLC and HPLC, 20 DPPH free-radical scavengers with purity higher than 85% and yield more than 2 mg were screened, in which compound B4-16 had relatively higher yield and stronger free radical scavenging activity. The formula of compound B4-16 was determined to be C10H10O4 (MW: 194) based on its FAB-MS, 1H-NMR, 13C-NMR, 1H-13C HMBC, IR spectra, and its structure was elucidated. It was identical with 5,8-dihydroxy-3-methyl-3,4-dihydroisocoumarin. At the concentration of 20 mumol/L, its DPPH free\|radical scavenging activity was as 1.67 times as that of vitamin C or 2.10 times as that of Vitamin E.

Amino acid concentrations in fluids from the bovine oviduct and uterus and in KSOM-based culture media

Amino acids in bovine oviductal and uterine fluids were measured and compared with those in modified simplex optimized medium (KSOM) supplemented with either fetal calf serum or Minimum Essential Medium amino acids in addition to bovine serum albumin, fetal calf serum or polyvinyl alcohol. Concentrations of cysteine, threonine, tryptophan, alanine, aspartate, glycine, glutamate, proline, beta-alanine, and citrulline were higher in oviductal fluids than in KSOM-based culture media. Nonessential and essential amino acids were present in ratios of 5:1 and 2:1 in oviductal and uterine fluids, respectively. Concentrations of alanine (3.7 mM), glycine (14.1 mM) and glutamate (5.5 mM) were high in oviductal fluids, comprising 73% of the free amino acid pool. Of the amino acids measured in uterine fluids, alanine (3.1 mM), glycine (12.0 mM), glutamate (4.2 mM), and serine (2.7 mM) were highest in concentration, and the first three comprised 43% of the free amino acid pool. In conclusion, amino acid concentrations in the bovine reproductive tract were substantially higher than those in embryo culture media. Certain amino acids, particularly alanine, glutamate, glycine and taurine, are present in strikingly high concentrations in both oviductal and uterine fluids, suggesting that they might play important roles in early embryo development. The particular pattern of amino acid concentrations may be an important factor to be considered for the improvement of embryo culture media.

Adenovirus-mediated transfer of type IV collagen alpha5 chain cDNA into swine kidney in vivo: deposition of the protein into the glomerular basement membrane

Gene therapy of Alport syndrome (hereditary nephritis) aims at the transfer of a corrected type IV collagen alpha chain gene into renal glomerular cells responsible for production of the glomerular basement membrane (GBM). A GBM network composed of type IV collagen molecules is abnormal in Alport syndrome which leads progressively to kidney failure. The most common X-linked form of the disease is caused by mutations in the gene for the alpha5(IV) chain, the alpha5 chain of type IV collagen. Full-length human alpha5(IV) cDNA was expressed in HT1080 cells with an adenovirus vector, and the recombinant alpha5(IV) chain was shown to assemble into heterotrimers consisting of alpha3(IV) and alpha4(IV) chains, utilizing a FLAG epitope in the recombinant alpha5(IV) chain. The results indicate that correction of the molecular defect in Alport syndrome is possible. Previously, we had developed an organ perfusion method for effective in vivo gene transfer into glomerular cells. In vivo perfusion of pig kidneys with the recombinant adenovirus resulted in expression of the alpha5(IV) chain in kidney glomeruli as shown by in situ hybridization and its deposition into the GBM was shown by immunohistochemistry. The results strongly suggest future possibilities for gene therapy of Alport syndrome.

Oxidative damage induced by the injection of HIV-1 Tat protein in the rat striatum

Oxidative stress has been hypothesized to play a role in the pathogenesis of different neurodegenerative disorders, including HIV-related dementia. Tat, a nonstructural protein of HIV, is implicated in potentiation of neuronal apoptosis by mechanisms involving the disruption of calcium homeostasis and oxidative stress. The injection of Tat caused an increase of protein carbonyl formation in the rat striatum. Increased oxidative modification of proteins occurred early after Tat injection and preceded Tat-mediated astrogliosis. Immunostaining of brain sections demonstrated that an area of prominent protein carbonyl immunoreactivity surrounded an injection site in the striatum of Tat-injected rats. Intense protein carbonyl immunoreactivity was localized in cell bodies. Our study suggests that increased protein oxidation may be an important part of the mechanism of Tat neurotoxicity.

Atomic carbon as a terminal ligand: studies of a carbidomolybdenum anion featuring solid-state (13)C NMR data and proton-transfer self-exchange kinetics

Anion [CMo(N[R]Ar)(3)](-) (R = C(CD(3))(2)CH(3) or (t)Bu, Ar = 3,5-C(6)H(3)Me(2)) containing one-coordinate carbon as a terminal substituent and related molecules have been studied by single-crystal X-ray crystallography, solution and solid-state (13)C NMR spectroscopy, and density functional theory (DFT) calculations. Chemical reactivity patterns for [CMo(N[R]Ar)(3)](-) have been investigated, including the kinetics of proton-transfer self-exchange involving HCMo(N[R]Ar)(3), the carbidomolybdenum anion's conjugate acid. While the Mo triple bond C bond lengths in [K(benzo-15-crown-5)(2)][CMo(N[R]Ar)(3)] and the parent methylidyne, HCMo(N[R]Ar)(3), are statistically identical, the carbide chemical shift of delta 501 ppm is much larger than the delta 282 ppm shift for the methylidyne. Solid-state (13)C NMR studies show the carbide to have a much larger chemical shift anisotropy (CSA, 806 ppm) and smaller (95)Mo--(13)C coupling constant (60 Hz) than the methylidyne (CSA = 447 ppm, (1)J(MoC) = 130 Hz). DFT calculations on model compounds indicate also that there is an increasing MoC overlap population on going from the methylidyne to the terminal carbide. The pK(a) of methylidyne HCMo(N[R]Ar)(3) is approximately 30 in THF solution. Methylidyne HCMo(N[R]Ar)(3) and carbide [CMo(N[R]Ar)(3)](-) undergo extremely rapid proton-transfer self-exchange reactions in THF, with k = 7 x 10(6) M(-1) s(-1). Besides being a strong reducing agent, carbide [CMo(N[R]Ar)(3)](-) reacts as a nucleophile with elemental chalcogens to form carbon-chalcogen bonds and likewise reacts with PCl(3) to furnish a carbon-phosphorus bond.

Observation of wounding characteristics in dogs wounded by super velocity projectile

OBJECTIVE

To understand wounding characteristics in dogs wounded by super velocity projectile with a purpose of providing a basis for prevention and treatment of such wounds.

METHODS

A specially-made explosive gun was used to shoot aluminium bullet weighing 3.0 g and 1.4 g to injure both legs of dogs at velocities of 2330 m/s, 3200 m/s and 4250 m/s, respectively, and the soap specially made was also shot. At the same time, steel ball of 1.03 g was shot with a Type 53 smooth chamber gun at a speed of 1280 m/s. Within 30 min after wounding, debridement and pathological anatomy were performed and specimens were taken for light microscope observation.

RESULTS

When the dogs were wounded by the 3 g bullet at speed of 2330 m/s, the entrance of the left leg was penetrated explosively with a defect area of 225 cm(2), and the femur trunk was also injured and the residual femur had comminution fracture. The exit of the right leg was blindly wounded with a defect area of 63 cm(2), but only the skin was not penetrated. Both testes and part pelvis were injured too. Under light microscope, degenerative myofibers and bleeding of the spatium between the myofibers could be found at the place 4 cm away from the wounding track. Furthermore, serious bleeding of the bladder and blood vessels of the brain could be observed. The lungs showed changes of blast injury. Vacuolar change was presented in the cytoplasm of hepatocytes. Injuries of the animals in other two experimental groups were similar to those described above, but the defect area of the wounded track was 124 cm(2) in the group of 4250 m/s. Injuries caused by the steel ball were milder than caused by the explosive gun. The volume of the residual cavity in the soap was 5000 ml.

CONCLUSIONS

The super-velocity projectile causes destructive damage to the local tissues and multi-organ injuries. Therefore, the practical medical care needs not only amputation but also management of multi-organ injuries.

Cyclosporine therapeutic and toxic effects may be related to different cyclosporine concentration zones in plasma

Different cyclosporine concentration zones can exist in plasma due to the temperature dependency in distribution and association, therefore cyclosporine therapeutic and toxic effects may partially be related to these concentration zones.

The role of 5-hydroxytryptamine1A and 5-hydroxytryptamine1B receptors in modulating spinal nociceptive transmission in normal and carrageenan-injected rats

Single unit extracellular recordings from the dorsal horn neurons were obtained with glass micropipettes in pentobarbital-anesthetized rats. A total of 115 wide dynamic range (WDR) neurons were studied in 94 rats. In normal rats, the size of nociceptive receptive fields (RFs) of WDR neurons was approximately 123.3 +/- 8.21 mm2 (n = 88). Following carrageenan-induced inflammation, the RFs were markedly enlarged (332.4 +/- 30.1 mm2, n = 27, P < 0.001). The frequency of background activity of the WDR neurons in carrageenan-injected rats (11.3 +/- 2.1 imp/s, n = 27) was greater than that in normal rats (7.1 +/- 0.8 imp/s, n = 88, P < 0.05). In 82% of WDR neurons in normal rats, there was a separation between the A- and C-responses. In contrast, in 67% of the neurons in carrageenan-injected rats, the response to suprathreshold electrical stimuli was a long train with no separation between the A- and C-responses. In carrageenan-injected rats, the magnitude and duration of the nociceptive responses were significantly increased compared to those in normal rats, and the average C-response threshold (7.7 +/- 1.1 mA, n = 27) was lower than that in normal rats (10.4 +/- 0.7 mA, n = 88, P < 0.05). Intrathecal injection of the 5-hydroxytryptamine(1A) (5-HT1A) receptor agonist 8-hydroxy-DPAT hydroxybromide (8-OH-DPAT) (0.305, 1.525, 3.05, and 15.25 mM) dose-dependently increased Adelta- and C-responses and post-discharge in most of the WDR neurons. Following carrageenan-induced inflammation, the 8-OH-DPAT-induced facilitatory effect on Adelta- and C-responses and post-discharge was significantly enhanced (P < 0.05). Intrathecal injection of the 5-hydroxytryptamine1B (5-HT1) receptor agonist CGS12066A (0.222, 1.11, 2.22, and 11.1 mM) dose-dependently enhanced the C-response and post-discharge without influencing the Adelta-response. In carrageenan-injected rats, CGS12066A not only enhanced the facilitatory effect on the C-response and post-discharge, but also facilitated the Adelta-response. Intrathecal injection of the 5-HT(1A) receptor antagonist NAN-190 (0.2 mM) alone did not influence Adelta- and C-responses and post-discharge of WDR neurons in normal rats. When 0.2 mM NAN-190 was co-administered with 3.05 mM 8-OH-DPAT, the facilitatory effect of 8-OH-DPAT on Adelta- and C-responses and post-discharge was completely antagonized, whereas CGS12066A-induced facilitation on the C-response and post-discharge was not influenced by co-administration of 0.2 mM NAN-190 and CGS12066A. These data suggest that 5-HT1A and 5-HT1B receptor subtypes mediate the facilitatory effect of 5-HT on nociceptive processing in the spinal cord of rats. The excitability of dorsal horn WDR neurons and the sensitivity of the neurons to intrathecal 5-HT1A and 5-HT1B receptor agonists might increase following carrageenan-induced inflammation.

Muscular Asthenopia and Eccentric Ablation After Photorefractive Keratectomy

PURPOSE

To investigate the relationship between muscular asthenopia and eccentric ablation after photorefractive keratectomy (PRK).

METHODS

Sixteen eyes of eight myopic patients whose muscular asthenopia was corrected by subjectively accepted spectacle prism after PRK, with visual acuity better than 0.8, were followed for 6 to 14 months. On the basis of preoperative and post-operative data and corneal topography, we calculated the total corrected corneal power using the Holladay formula and then measured the ablation eccentricity (h, millimeters) and its direction. According to the formula delta approximately equals Dh, the prism effective value (delta) caused by the eccentric ablation was computed and compared with the objectively accepted spectacle prism.

RESULTS

The subjectively accepted spectacle prisms were similar to calculated values from the formula. Mean difference was 0.10 +/- 0.25delta. The direction of the subjectively accepted prism was in the direction of the ablation deviation.

CONCLUSIONS

Eccentric ablation is an important cause of muscular visual asthenopia after PRK. The asthenopia may be corrected by spectacle prism. The spectacle prism value may be estimated by the formula delta approximately equals Dh.

Effects of dopaminergic agents on carrageenan hyperalgesia after intrathecal administration to rats

The present study explored the role of dopaminergic transmission in spinal cord in a model of carrageenan-induced inflammatory pain by examining the effects of selective agonists and antagonists of dopamine receptors. The results were as follows: (1) trans-(-)-4aR-4,4a,5,6,7,8,8a,9-octahydro-5-propyl-1H-pyrazolo[3,4-g] quinoline hydrochloride (LY171555), a dopamine D(2) receptor agonist, produced anti-hyperalgesia (150 and 300 nmol) or hypoalgesia (300 nmol) in the inflamed hindpaws and non-inflamed hindpaws, respectively; spiperone hydrochloride (8-[4-(4-fluorophenyl)-4-oxobutyl]-1-phenyl-1,3,8-triazaspiro[4,5]decan-4-one hydrochloride), a dopamine D(2) receptor antagonist, decreased the pain threshold of non-inflamed hindpaws (300 nmol). (2) (+/-)-SKF38393 hydrochloride ((+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride), a dopamine D(1) receptor agonist, had no effect on either hindpaw, even at a higher dose (300 nmol); R(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (R(+)-SCH23390 hydrochloride), a dopamine D(1) receptor antagonist, induced anti-hyperalgesia in the inflamed hindpaws (300 nmol). The present results suggest that the dopaminergic system in the spinal cord is involved in the central modulation of inflammatory hyperalgesia, and that the different effects are probably induced by different receptors.

Early onset of spontaneous activity in uninjured C-fiber nociceptors after injury to neighboring nerve fibers

Ligation and transection of the L5 spinal nerve in the rat lead to behavioral signs of pain and hyperalgesia. Discharge of injured nociceptors has been presumed to play a role in generating the pain. However, A fibers, but not C fibers, in the injured L5 spinal nerve have been shown to develop spontaneous activity. Moreover, an L5 dorsal root rhizotomy does not reverse this pain behavior, suggesting that signals from other uninjured spinal nerves are involved. We asked if abnormal activity develops in an adjacent, uninjured root. Single nerve fiber recordings were made from the L4 spinal nerve after ligation and transection of the L5 spinal nerve. Within 1 d of the lesion, spontaneous activity developed in approximately half of the C fiber afferents. This spontaneous activity was at a low level (median rate, seven action potentials/5 min), originated distal to the dorsal root ganglion, and was present in nociceptive fibers with cutaneous receptive fields. The incidence and level of spontaneous activity were similar 1 week after injury. The early onset of spontaneous activity in uninjured nociceptive afferents could be the signal that produces the central sensitization responsible for the development of mechanical hyperalgesia. Because L4 afferents comingle with degenerating L5 axons in the peripheral nerve, we hypothesize that products associated with Wallerian degeneration lead to an alteration in the properties of the adjacent, uninjured afferents.

The control of body orientation and center of mass location under asymmetrical loading

This study examined how whole body center of mass (COM) in the medial-lateral direction and spatial orientation of body segments changed during quiet stance when a weight was loaded on asymmetrically on the right side of the pelvis. The load corresponded to 10 and 30% of body weight (BW) of each individual subject, and the stance width was varied from narrow (7.6 cm) to normal (20 cm) and to wide (33 cm). A total of 10 healthy young subjects (18-30 years of age) participated in the study. The results indicated that the COM location was significantly shifted towards the loaded side (about 1.2 cm with a 10% BW load and 3 cm with a 30% BW load). In addition, COM was closer to the center with a narrow stance (0.38 cm to the right of the center) than both normal and wide stance (about 1 cm to the right). However, the COM shifts for all test conditions were smaller (<50%) than that of the theoretically predicted values. The smaller shift in COM position appeared to be mostly due to the change in spatial orientation of the pelvis and lower extremity (about 2.5 degrees change with a 10% BW load, and 4.5 degrees change with a 30% BW load), while maintaining the upper body orientation relatively unchanged (less than 2 degrees with a 30% BW load). This strategy may allow increased stability of the upright stance with minimal amount of muscle activation.

Cantilever-based optical deflection assay for discrimination of DNA single-nucleotide mismatches

Characterization of single-nucleotide polymorphisms is a major focus of current genomics research. We demonstrate the discrimination of DNA mismatches using an elegantly simple microcantilever-based optical deflection assay, without the need for external labeling. Gold-coated silicon AFM cantilevers were functionalized with thiolated 20- or 25-mer probe DNA oligonucleotides and exposed to target oligonucleotides of varying sequence in static and flow conditions. Hybridization of 10-mer complementary target oligonucleotides resulted in net positive deflection, while hybridization with targets containing one or two internal mismatches resulted in net negative deflection. Mismatched targets produced a stable and measurable signal when only a four-base pair stretch was complementary to the probe sequence. This technique is readily adaptable to a high-throughput array format and provides a distinct positive/negative signal for easy interpretation of oligonucleotide hybridization.

Exploiting pattern and sustainable development of marginal lands in the Three Gorge Reservoir Areas

This paper studied the distribution and utilization status, reasonable exploitation patterns and potential productivity, and sustainable development of marginal lands in the Three Gorge Reservoir Areas. It has been pointed that problems of the soil fertility degradation, poor productivity in crop lands, natural disasters and environmental deterioration existed in all the exploited marginal lands. In order to maintain the sustainability of the marginal lands, following measure have been proposed: prohibiting cultivation in the crop lands with a slope more than 25 degrees, restoring vegetation in the slope more than 25 degrees, strengthening the basic agricultural construction, establishing the production base of woody feeds and oils, establishing a multi-dimensional management model with reasonable structure and optimum function for forestry, agriculture and fishing.