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.

Role of the arginine-nitric oxide pathway in the regulation of vascular smooth muscle cell proliferation

The objective of this study was to elucidate the mechanisms by which nitric oxide (NO) inhibits rat aortic smooth muscle cell (RASMC) proliferation. Two products of the arginine-NO pathway interfere with cell growth by distinct mechanisms. N(G)-hydroxyarginine and NO appear to interfere with cell proliferation by inhibiting arginase and ornithine decarboxylase (ODC), respectively. S-nitroso-N-acetylpenicillamine, (Z)-1-[N-(2-aminoethyl)-N-(2-aminoethyl)-amino]-diazen-1-ium-1,2-diolate, and a nitroaspirin derivative (NCX 4016), each of which is a NO donor agent, inhibited RASMC growth at concentrations of 1-3 microM by cGMP-independent mechanisms. The cytostatic action of the NO donor agents as well as alpha-difluoromethylornithine (DFMO), a known ODC inhibitor, was prevented by addition of putrescine but not ornithine. These observations suggested that NO, like DFMO, may directly inhibit ODC. Experiments with purified, recombinant mammalian ODC revealed that NO inhibits ODC possibly by S-nitrosylation of the active site cysteine in ODC. DFMO, as well as the NO donor agents, interfered with cellular polyamine (putrescine, spermidine, spermine) production. Conversely, increasing the expression and catalytic activity of arginase I in RASMC either by transfection of cells with the arginase I gene or by induction of arginase I mRNA with IL-4 resulted in increased urea and polyamine production as well as cell proliferation. Finally, coculture of rat aortic endothelial cells, which had been pretreated with lipopolysaccharide plus a cytokine mixture to induce NO synthase and promote NO production, caused NO-dependent inhibition of target RASMC proliferation. This study confirms the inhibitory role of the arginine-NO pathway in vascular smooth muscle proliferation and indicates that one mechanism of action of NO is cGMP-independent and attributed to its capacity to inhibit ODC.

Rescue of contractile parameters and myocyte hypertrophy in calsequestrin overexpressing myocardium by phospholamban ablation

Cardiac-specific overexpression of murine cardiac calsequestrin results in depressed cardiac contractile parameters, low Ca(2+)-induced Ca(2+) release from sarcoplasmic reticulum (SR) and cardiac hypertrophy in transgenic mice. To test the hypothesis that inhibition of phospholamban activity may rescue some of these phenotypic alterations, the calsequestrin overexpressing mice were cross-bred with phospholamban-knockout mice. Phospholamban ablation in calsequestrin overexpressing mice led to reversal of the depressed cardiac contractile parameters in Langendorff-perfused hearts or in vivo. This was associated with increases of SR Ca(2+) storage, assessed by caffeine-induced Na(+)-Ca(2+) exchanger currents. The inactivation time of the L-type Ca(2+) current (I(Ca)), which has an inverse correlation with Ca(2+)-induced SR Ca(2+) release, and the relation between the peak current density and half-inactivation time were also normalized, indicating a restoration in the ability of I(Ca) to trigger SR Ca(2+) release. The prolonged action potentials in calsequestrin overexpressing cardiomyocytes also reversed to normal upon phospholamban ablation. Furthermore, ablation of phospholamban restored the expression levels of atrial natriuretic factor and alpha-skeletal actin mRNA as well as ventricular myocyte size. These results indicate that attenuation of phospholamban function may prevent or overcome functional and remodeling defects in hypertrophied hearts.

[Effect of thyroxine upon prevention of recurrence of Graves' disease treated with antithyroid drugs]

OBJECTIVE

To investigate the effect of thyroxine upon the prevention of recurrence of Graves disease after treatment by antithyroid drugs.

METHODS

Sixty patients newly diagnosed as Graves disease were treated with methimazole for 6 months and then randomly distributed into three groups. Patient in group A and group C received small dose of methimazole plus L-T(4) 50 microgram/d, and patients in group B were treated with methimazole in small dose only. Twenty four months later, only L-T(4) 50 microgram/d, without methimazole, was administered to the patients of group A; methimazole in maintenance dose was administered continuously to the patients of group B, and patients in group C were treated with methimazole in maintenance dose plus L-T(4) 50 microgram/d. Such treatments lasted 6 months. Post-treatment follow-up survey was conducted to the three groups.

RESULTS

The titers of thyroid-stimulating Ab (TSAb) in groups A and C were lower than that in group B. However, the recurrence rates among the three groups (4/20, 20%; 4/20, 25%; and 4/20, 20% respectively) were not significantly different.

CONCLUSION

Both treatment of Graves' disease with methimazole plus L-T4 and treatment with prolonged use of methimazole cannot reduce the recurrence rate more effectively than treatment with only methimazole. The level of TSAb is not the only factor that influences the recurrence of Graves disease.

Isolation and characterization of mouse MUC18 cDNA gene, and correlation of MUC18 expression in mouse melanoma cell lines with metastatic ability

The cell surface adhesion molecule human MUC18 (huMUC18 or Mel-CAM) has been postulated to play a key pathogenic role in metastatic melanoma progression. To establish an immunocompetent syngeneic mouse model that would greatly facilitate our understanding of the role of MUC18 in the metastatic behavior of melanoma, we cloned and characterized the mouse MUC18 (muMUC18) cDNA gene. The gene was amplified by RT-PCR and RACE of the poly(A)+RNA isolated from the mouse melanoma cell line B16F10/Queens. The cloned muMUC18 cDNA gene contained 28 nucleotides of 5'-UTR, 908 nucleotides of 3'-UTR, and an open reading frame (ORF) of 1947 nucleotides encoding a protein of 648 amino acids, which is two amino acids longer than huMUC18. The size of the muMUC18 mRNA is about 3 kb with a shorter 3'-UTR than the huMUC18 mRNA (about 3.3 kb). Besides, the sequence in the 3' UTR of the two mRNAs is diverse with only 31% identity. The 5'-UTR and coding sequences of the muMUC18 cDNA are 72.4 and 80.6% identical to those of huMUC18, respectively. The deduced amino acid sequence of the muMUC18 cDNA is 76.2% identical to that of huMUC18. The amino acid sequences deduced from MUC18 cDNA sequences from six other mouse melanoma cell lines are identical except one to three residues, suggesting that the muMUC18 cDNA sequence determined in this report is correct. The muMUC18 protein is predicted to be slightly more acidic than the human protein. The levels of muMUC18 mRNA and protein in nine mouse melanoma cell lines were directly proportional to their ability to establish metastatic colonies in lungs of syngeneic mice. Most biological functions of the muMUC18 may be similar to the huMUC18.

Head movement during sudden base translations as a measure of risks for falls in the elderly

OBJECTIVE

To determine whether head movement in response to a sudden platform translation differs between healthy young subjects and healthy elderly with and without, bipedal sensory loss.

DESIGN

A cross-sectional study with four-way comparison on subject grouping and three test conditions.

BACKGROUND

Head movement has been used as a measure of balance in the elderly during voluntary movements. Studies during involuntary movement, however, are limited. Moreover, it is not clear how head movement during involuntary activities relates to postural balance and susceptibility to falls.

METHODS

Head movement during a sudden base translation was measured in three subject groups: 9 healthy young, 10 healthy elderly adults and 10 elderly adults with vibratory sensation loss under the feet. The surface compliance of the supporting base, the direction of the base translation and the visual condition were all varied.

RESULTS

There were significant differences among the three groups in head range of excursion (5 degrees, 9 degrees, 13 degrees for the young, elderly, and elderly with severe vibratory sensation loss, respectively), onset time (120, 150, 180 ms), and the time from peak to peak (38, 29, 25 ms). A backward base movement increased the head movement more than a forward base movement.

CONCLUSIONS

During sudden base translation balance tasks, head movement is significantly increased in the elderly, especially in those elderly adults who are susceptible to falls. The results suggest that an increased head movement in the elderly might be an indication of increased risks for falls.