AB0619 PROGNOSTIC FACTORS OF PATIENTS WITH ANTI-MDA5 ANTIBODY-POSITIVE DERMATOMYOSITIS COMPLICATED WITH INTERSTITIAL PNEUMONIA -A JAPANESE SINGLE CENTER STUDY-

Background:

Anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5 Ab)-positive dermatomyositis (DM) is frequently associated with rapidly progressive interstitial pneumonia (RPIP), whose prognosis is assumed to be poor[1]. Although outcome of DM-RPIP has been reported to be improved by early immunosuppressive therapy, we still experience the cases with severe outcome. Only several reports mentioned the prognostic factors and they have not been fully elucidated.

Objectives:

To identify the predictors of prognosis in patients with anti-MDA5 Ab-positive DM associated with interstitial pneumonia (DM-IP).

Methods:

Anti-MDA5 Ab-positive DM-IP patients admitted to Fujita Health University Hospital between January 2010 and October 2019 were consecutively included and stratified into 2 groups, the survived and the deceased groups. DM was diagnosed according to the criteria proposed by Bohan and Peter[2]. Clinically amyopathic DM was diagnosed according to the criteria proposed by Sontheimer [3]. Diagnosis of IP was based on findings of high resolution CT scan (HRCT). The definition of RPIP was rapid exacerbation of hypoxemia or HRCT findings in a period of days to one month after the onset. Clinical features and prognosis of the patients were collected retrospectively and compared between groups. Candidates of predictors are extracted by the univariable analysis using Fisher’s exact test for dichotic parameters and Wilcoxon signed-rank test for continuous parameters and multivariable analysis using logistic regression analysis. Receiver operating characteristic (ROC) curve analysis was examined to obtain the cut-off level. Survival was examined using Kaplan-Meier method and Log-rank test.

Results:

Twenty-one patients were involved. Eight were deceased and 13 were survived. The deceased group had a higher ratio of male (75% versus 25%, p= 0.018). All deceased cases were with RPIP and 67 % in the survived cases. Levels of serum ferritin (4490 versus 646 ng/mL, p = 0.0026), CRP (2.1 versus 0.9 mg/dL, p = 0.0490), CK (1150 versus 290 U/L, p = 0.017), AST (194 versus 108 U/L, p = 0.025) and LDH (674 versus 368 U/L, p = 0.011) were higher in the deceased group. Interestingly, skin ulcers were tended to be more frequent (12.5% versus 87.5%, p= 0.0587), and anti-SS-A antibody was also more frequently detected (14.3% versus 85.7%, p=0.0072) in the survived group. Using ROC analysis cut-off values were 963 ng/mL for serum ferritin level (sensitivity 100%, specificity 83%), 0.7 mg/dL for CRP (sensitivity 75%, specificity 69%), 308 U/L for CK (sensitivity 88%, specificity 77%), 62 U/L for ALT (sensitivity 100%, specificity 62%), and 454 U/L for LDH (sensitivity 88%, specificity 77%). Patients were divided into two groups based on these cut-offs or based on dichotic parameters and survival was examined between 2 groups. Except CRP and anti-SS-A antibody, survival was significantly worse in parameter-positive or higher groups. Interestingly, anti-SS-A antibody-positive group had better outcome compared with those without.

Conclusion:

In our analysis, novel candidates such as serum CK, AST, and LDH levels were newly extracted and parameters previously reported was also included and those were also associated with the clinical outcome. In addition, anti-SS-A antibody was identified as a novel protective factor associated with a good outcome.

References:

[1]Nakashima R, Hosono Y, Mimori T. Clinical significance and new detection system of autoantibodies in myositis with interstitial lung disease. Lupus 2016;25:925-33.

[2]Bohan A, Peter JB. Polymyositis and dermatomyositis. N Eng J Med 1975;292:344-7.

[3]Sontheimer RD. Dermatomyositis: an overview of recent progress with emphasis on dermatologic aspects. Dermatol Clin 2000;20:387-408.

Disclosure of Interests:

None declared

Precise let-7 expression levels balance organ regeneration against tumor suppression

The in vivo roles for even the most intensely studied microRNAs remain poorly defined. Here, analysis of mouse models revealed that let-7, a large and ancient microRNA family, performs tumor suppressive roles at the expense of regeneration. Too little or too much let-7 resulted in compromised protection against cancer or tissue damage, respectively. Modest let-7 overexpression abrogated MYC-driven liver cancer by antagonizing multiple let-7 sensitive oncogenes. However, the same level of overexpression blocked liver regeneration, while let-7 deletion enhanced it, demonstrating that distinct let-7 levels can mediate desirable phenotypes. let-7 dependent regeneration phenotypes resulted from influences on the insulin-PI3K-mTOR pathway. We found that chronic high-dose let-7 overexpression caused liver damage and degeneration, paradoxically leading to tumorigenesis. These dose-dependent roles for let-7 in tissue repair and tumorigenesis rationalize the tight regulation of this microRNA in development, and have important implications for let-7 based therapeutics.

DOI:http://dx.doi.org/10.7554/eLife.09431.001

The development of animals is guided by the expression of certain genes at critical moments. Many different mechanisms control development; in one of them, the expression of genes can be decreased by molecules called microRNAs. In particular, the group of microRNAs called let-7 has been intensively studied in roundworms and fruit flies. Although mammals have extremely similar let-7 microRNAs they seem to be more important during adulthood.

Previous studies using cells grown in the laboratory have shown that mammalian let-7 microRNAs decrease cell proliferation and cell growth. Furthermore, in mouse models of various cancers, let-7 microRNAs often reduce tumour growth when they are supplied to adult mice. Therefore, overall the let-7 group has been classified as genes that act to suppress tumors, and thus protect mice (and most likely humans too) from cancers. However, in-depth analysis of let-7 microRNAs was still missing.

Wu and Nguyen et al. have now studied mice with liver cancer using strains where they were able to regulate the levels of let-7. These mice overproduce a strong cancer-inducing gene in the liver; half were used as controls and the other half were further engineered to have moderately elevated levels of let-7 expression. Most of the control mice got large cancerous tumors, but only a few mice in the other group developed cancers and the tumors were smaller. This confirmed that let-7 hinders tumor formation.

Wu and Nguyen et al. also observed that the protected mice were less able to regenerate their liver tissues. Further experiments showed that deleting just two out of ten let-7 microRNAs enhanced the mice’s ability to regenerate liver tissue after injury. These findings indicate that let-7 microRNAs slow down the growth of both cancerous and normal cells. Lastly, when let-7 levels were raised to very high levels for a prolonged amount of time this actually led to liver damage and subsequent tumor formation.

This last observation may have important consequences for possible cancer therapies. Some scientists have shown that providing extra let-7 can slow or even reverse tumour growth, but the findings here clearly point out that too much let-7 could actually worsen the situation. Since the let-7 family comprises a handful of microRNAs in mammals, in the future it will also be important to find out to what extent these molecules play overlapping roles and how much they differ.

DOI:http://dx.doi.org/10.7554/eLife.09431.002

Amino Acid Sequences of Trypsin Inhibitors from Oriental Pickling Melon (Cucumis melL. var.ConomonMakino) Seeds

Three inhibitors (CMCTI-I, II, and III) were isolated from oriental pickling melon (Cucumis melo L. var. Conomon Makino) seeds by acetone precipitation, gel filtration, and reversed phase chromatography. The amino acid sequences of these inhibitors were: [table; see text] The reactive sites (P1 and P1' sites) of these inhibitors are presumed to be the Lys-Ile indicated by an arrow, comparing them with other squash family inhibitors. All three inhibitors can inhibit lysyl endopeptidase and trypsin at the enzyme-inhibitor ratio of 1:1.

A network of heterochronic genes including Imp1 regulates temporal changes in stem cell properties

Stem cell properties change over time to match the changing growth and regeneration demands of tissues. We showed previously that adult forebrain stem cell function declines during aging because of increased expression of let-7 microRNAs, evolutionarily conserved heterochronic genes that reduce HMGA2 expression. Here we asked whether let-7 targets also regulate changes between fetal and adult stem cells. We found a second let-7 target, the RNA binding protein IMP1, that is expressed by fetal, but not adult, neural stem cells. IMP1 expression was promoted by Wnt signaling and Lin28a expression and opposed by let-7 microRNAs. Imp1-deficient neural stem cells were prematurely depleted in the dorsal telencephalon due to accelerated differentiation, impairing pallial expansion. IMP1 post-transcriptionally inhibited the expression of differentiation-associated genes while promoting the expression of self-renewal genes, including Hmga2. A network of heterochronic gene products including Lin28a, let-7, IMP1, and HMGA2 thus regulates temporal changes in stem cell properties.

DOI:http://dx.doi.org/10.7554/eLife.00924.001

Stem cells are found throughout the body, and play key roles in promoting tissue growth during fetal development, and in maintaining tissues in the adult. When stem cells divide, they can either give rise to more stem cells, or they can generate specialized cells required for tissue function. However, the properties of stem cells must change over time to match the changing growth and regeneration demands of tissues.

A previous study by Nishino et al. has shown that expression of a micro RNA molecule called let-7 increases throughout adulthood, and this reduces the activity of stem cells in older animals. Now, Nishino et al. report that let-7, and other genes it regulates, also control the dramatic changes that occur in the properties of stem cells between fetal development and adulthood. Whereas stem cells in the fetal forebrain undergo rapid division and are capable of generating many different cell types, stem cells in the adult forebrain divide less often and can generate only a few specific types of cell. While Nishino et al. performed their study on stem cells in the brain, their results are likely to apply also to stem cells in other tissues.

Nishino et al. show that let-7 regulates the production of an RNA binding protein called IMP1. Mice with stem cells that lack IMP1 have a smaller cerebral cortex than normal mice because their stem cells undergo fewer rounds of division before committing to become brain cells. Additional experiments revealed that IMP1 inhibits the expression of genes that trigger stem cells to commit to specific fates and promotes the expression of genes related to self-renewal.

These results indicate that the gene that encodes IMP1 is expressed in fetal neural stem cells, but not in adult neural stem cells, and that the reduced production of this protein contributes to the developmental switch from highly proliferative neural stem cells in the fetus to the more quiescent stem cells found in adults. Further studies are likely to identify many more targets of let-7 that enable stem cells to adapt their properties to the changing needs of the organism over time.

These results are interesting because let-7-regulated networks were first discovered based on their ability to regulate the timing of developmental transitions in worms. This suggests that the mechanisms employed by mammalian tissue stem cells to regulate changes in their properties over time, are at least partly evolutionarily conserved mechanisms inherited from invertebrates.

DOI:http://dx.doi.org/10.7554/eLife.00924.002

Oxide Quantum Structures for Future Electro-Photonics

We show our recent development on the epitaxial growth of oxide thin films by laser molecular beam epitaxy directed towards a possible new field of electro-photonics based on metal-oxide quantum structures. Examples of quantum structures include superlattices and tunnel junctions (2-dimensional), superconducting quantum wire arrays (1-dimensional), and quantum dots for photonic application (O-dimensional). For fabricating such structures, it is vitally important to prepare the substrate surface and to understand the growth dynamics. Such electro-phptonic functions as Josephson effect in high Tc tunnel junctions and excitonic UV-laser operation at room temperature in self-organized hexagonal nanocrystal ZnO films are presented.

Neutrophil CD64 expression in the diagnosis of local musculoskeletal infection and the impact of antibiotics

We examined the usefulness of neutrophil CD64 expression in detecting local musculoskeletal infection and the impact of antibiotics on its expression. Of 141 patients suspected of musculoskeletal infection, 46 were confirmed by microbiological culture to be infected and 95 had infection excluded. The median CD64 count of patients with localised infection was 2230 molecules per cell (interquartile range (IQR) 918 to 4592) and that of the patients without infection was 937 molecules per cell (IQR 648 to 1309) (p < 0.001). The level of CD64 correlated with the CRP level in patients with infection, but not in those without infection (r = 0.59, p < 0.01). Receiver operator characteristic curve analysis revealed that CD64 was a good predictor of local infection. When the patients were subdivided into two groups based on the administration of antibiotics at the time of CD64 sampling, the sensitivity for detecting infection was better in those who had not received antibiotics.

These results suggest that measurement of CD64 expression is a useful marker for local musculoskeletal infection.

Hmga2 promotes neural stem cell self-renewal in young but not old mice by reducing p16Ink4a and p19Arf Expression

Stem cells persist throughout life in diverse tissues by undergoing self-renewing divisions. Self-renewal capacity declines with age, partly because of increasing expression of the tumor suppressor p16(Ink4a). We discovered that the Hmga2 transcriptional regulator is highly expressed in fetal neural stem cells but that expression declines with age. This decrease is partly caused by the increasing expression of let-7b microRNA, which is known to target HMGA2. Hmga2-deficient mice show reduced stem cell numbers and self-renewal throughout the central and peripheral nervous systems of fetal and young-adult mice but not old-adult mice. Furthermore, p16(Ink4a) and p19(Arf) expression were increased in Hmga2-deficient fetal and young-adult stem cells, and deletion of p16(Ink4a) and/or p19(Arf) partially restored self-renewal capacity. let-7b overexpression reduced Hmga2 and increased p16(Ink4a)/p19(Arf) expression. Hmga2 thus promotes fetal and young-adult stem cell self-renewal by decreasing p16(Ink4a)/p19(Arf) expression. Changes in let-7 and Hmga2 expression during aging contribute to the decline in neural stem cell function.

Hmga2 promotes neural stem cell self-renewal in young but not old mice by reducing p16Ink4a and p19Arf Expression

Stem cells persist throughout life in diverse tissues by undergoing self-renewing divisions. Self-renewal capacity declines with age, partly because of increasing expression of the tumor suppressor p16(Ink4a). We discovered that the Hmga2 transcriptional regulator is highly expressed in fetal neural stem cells but that expression declines with age. This decrease is partly caused by the increasing expression of let-7b microRNA, which is known to target HMGA2. Hmga2-deficient mice show reduced stem cell numbers and self-renewal throughout the central and peripheral nervous systems of fetal and young-adult mice but not old-adult mice. Furthermore, p16(Ink4a) and p19(Arf) expression were increased in Hmga2-deficient fetal and young-adult stem cells, and deletion of p16(Ink4a) and/or p19(Arf) partially restored self-renewal capacity. let-7b overexpression reduced Hmga2 and increased p16(Ink4a)/p19(Arf) expression. Hmga2 thus promotes fetal and young-adult stem cell self-renewal by decreasing p16(Ink4a)/p19(Arf) expression. Changes in let-7 and Hmga2 expression during aging contribute to the decline in neural stem cell function.

CYP26A1 and CYP26C1 cooperatively regulate anterior-posterior patterning of the developing brain and the production of migratory cranial neural crest cells in the mouse

The appropriate regulation of retinoic acid signaling is indispensable for patterning of the vertebrate central nervous system along the anteroposterior (A-P) axis. Although both CYP26A1 and CYP26C1, retinoic acid-degrading enzymes that are expressed at the anterior end of the gastrulating mouse embryo, have been thought to play an important role in central nervous system patterning, the detailed mechanism of their contribution has remained largely unknown. We have now analyzed CYP26A1 and CYP26C1 function by generating knockout mice. Loss of CYP26C1 did not appear to affect embryonic development, suggesting that CYP26A1 and CYP26C1 are functionally redundant. In contrast, mice lacking both CYP26A1 and CYP26C1 were found to manifest a pronounced anterior truncation of the brain associated with A-P patterning defects that reflect expansion of posterior identity at the expense of anterior identity. Furthermore, Cyp26a1-/-Cyp26c1-/- mice fail to produce migratory cranial neural crest cells in the forebrain and midbrain. These observations, together with a reevaluation of Cyp26a1 mutant mice, suggest that the activity of CYP26A1 and CYP26C1 is required for correct A-P patterning and production of migratory cranial neural crest cells in the developing mammalian brain.

Regulation of retinoic acid distribution is required for proximodistal patterning and outgrowth of the developing mouse limb

Exogenous retinoic acid (RA) induces marked effects on limb patterning, but the precise role of endogenous RA in this process has remained unknown. We have studied the role of RA in mouse limb development by focusing on CYP26B1, a cytochrome P450 enzyme that inactivates RA. Cyp26b1 was shown to be expressed in the distal region of the developing limb bud, and mice that lack CYP26B1 exhibited severe limb malformation (meromelia). The lack of CYP26B1 resulted in spreading of the RA signal toward the distal end of the developing limb and induced proximodistal patterning defects characterized by expansion of proximal identity and restriction of distal identity. CYP26B1 deficiency also induced pronounced apoptosis in the developing limb and delayed chondrocyte maturation. Wild-type embryos exposed to excess RA phenocopied the limb defects of Cyp26b1(-/-) mice. These observations suggest that RA acts as a morphogen to determine proximodistal identity, and that CYP26B1 prevents apoptosis and promotes chondrocyte maturation, in the developing limb.

Meteorin: a secreted protein that regulates glial cell differentiation and promotes axonal extension

Glial cells are major components of the nervous system. The roles of these cells are not fully understood, however. We have now identified a secreted protein, designated Meteorin, that is expressed in undifferentiated neural progenitors and in the astrocyte lineage, including radial glia. Meteorin selectively promoted astrocyte formation from mouse cerebrocortical neurospheres in differentiation culture, whereas it induced cerebellar astrocytes to become radial glia. Meteorin also induced axonal extension in small and intermediate neurons of sensory ganglia by activating nearby satellite glia. These observations suggest that Meteorin plays important roles in both glial cell differentiation and axonal network formation during neurogenesis.

Effects of selected metal oxides on the dechlorination and destruction of PCDD and PCDF

OCDD and OCDF spiked silica/graphite based model fly ash containing various copper compounds and metal oxides were thermally treated under oxygen deficient conditions. All copper compounds tested showed a considerable dechlorination/hydrogenation reaction at 260 degrees C. After 30 min at 340 degrees C, less than 1% of the spiked OCDD and OCDF was recovered as T4CDD/F to OCDD/F. Other compounds tested demonstrated a lower rate of dechlorination compared to the copper compounds. However, all other metal oxides showed a small dechlorination effect at 260 degrees C, which was considerably increased at 340 degrees C. The model fly.ash containing the different copper compounds or metal oxides showed comparable PCDD and PCDF isomer patterns after thermal treatment. However, small differences were observed among the different tested compounds. The PCDD and PCDF isomer patterns on the model fly ashes were similar to patterns found during dechlorination experiments on fly ashes from waste incineration processes. Model fly ash containing Ca(OH)2 exhibited the highest destruction potential, but a low dechlorination potential. In contrast, model fly ash containing any of the remaining compounds tested, was found to predominantly dechlorinate the spiked OCDD and OCDF.

The binocular accommodative response in uncorrected ametropia

PURPOSE

To measure the changes in astigmatism and in the degree of anisometropia when ametropes respond to accommodative stimulation.

METHODS

The accommodative responses of ametropes were binocularly measured with an improved photorefractometer (PR-1100), which objectively measured binocular refraction in all meridians simultaneously, when a visual fixation target was shown in natural space at 5 and 0.5 m.

RESULTS

(1) Changes of astigmatism and anisometropia occur during binocular accommodation. (2) Changes of astigmatism mainly result from lag of accommodation in the horizontal meridian. (3) Changes of anisometropia result from the effort to focus. (4) The interaction of both eyes is suggested as the cause of the changes of astigmatism and anisometropia with accommodation. (5) In the majority of strong anisometropes (nonoverlapping group in this paper), the magnitude of anisometropia decreases (approaching isometropia) with accommodation.

CONCLUSION

Changes in astigmatism and anisometropia can occur during accommodation, and these interactions of both eyes with accommodation may contribute to the development and maintenance of binocular function.

Digital subtraction angiogram registration method with local distortion vectors to decrease motion artifact

We have been investigating registration methods for improving digital subtraction angiography (DSA) images to extract blood vessels by reducing artifacts due to body motion, such as rotation, contraction, and dilation. In this paper, we propose a new and simple DSA registration algorithm with local distortion vectors to reduce artifacts. According to the results, the proposed method works well for vascular system around the nasal cavity and the orbit of the head and neck DSA images, which cannot be observed clearly by conventional methods. Additionally, we have applied the proposed method to abdominal and leg DSA images.

The retinoic acid-inactivating enzyme CYP26 is essential for establishing an uneven distribution of retinoic acid along the anterio-posterior axis within the mouse embryo

Retinoic acid (RA), a derivative of vitamin A, plays a pivotal role in vertebrate development. The level of RA may be determined by the balance between its synthesis and degradation. We have examined the role of CYP26, a P450 enzyme that may degrade RA, by generating mutant mice that lack CYP26. CYP26(-/-) mice exhibited anomalies, including caudal agenesis, similar to those induced by administration of excess RA. The concentration of endogenous RA, as revealed by marker gene activity, was markedly increased in the tailbud of the mutant animals, in which CYP26 is normally expressed. Expression of T (Brachyury) and Wnt3a in the tailbud was down-regulated in CYP26(-/-) mice, which may underlie the caudal truncation. The lack of CYP26 also resulted in homeotic transformation of vertebrae as well as in misspecification of the rostral hindbrain associated with anterior expansion of RA-positive domains. These results suggest that local degradation of RA by CYP26 is required for establishing an uneven distribution of RA along the anterio-posterior axis, which is essential for patterning the hindbrain, vertebrae, and tailbud.

Two-step regulation of left-right asymmetric expression of Pitx2: initiation by nodal signaling and maintenance by Nkx2

Pitx2 is left--right (L--R) asymmetrically expressed initially in the lateral plate and later in primordial visceral organs. The transcriptional regulatory mechanisms that underlie L--R asymmetric expression of Pitx2 were investigated. Mouse Pitx2 has a left side-specific enhancer (ASE) that mediates both the initiation and maintenance of L--R asymmetric expression. This element contains three binding sites for the transcription factor FAST. The FAST binding sites function as Nodal-responsive elements and are sufficient for the initiation but not for the maintenance of asymmetric expression. The maintenance requires an Nkx2-5 binding site also present within the ASE. These results suggest that the left-sided expression of Pitx2 is directly initiated by Nodal signaling and is subsequently maintained by Nkx2. Such two-step control may represent a general mechanism for gene regulation during development.

Pharmacokinetic/pharmacodynamic relationship of eptazocine, a narcotic-antagonist analgesic, in rats

The relationship between the pharmacokinetics and the pharmacodynamics of eptazocine, a narcotic-antagonist analgesic, was investigated in rats. The analgesic effect of eptazocine (2.5, 5 and 10 mg/kg) following intravenous (i.v) administration was evaluated by both the Randall-Selitto method and the D'Amour-Smith method. The analgesic effects were determined before and at designed intervals for a period of 120 min after eptazocine administration, and are expressed as area under the effect-time curve (AUC(E)). The plasma concentration of eptazocine was determined by fluorescence HPLC and was analyzed with a two compartment open model using the nonlinear least-squares method. Eptazocine produced a dose-dependent analgesic effect. It was demonstrated that eptazocine has a linear relationship between AUC(E) and the area under the plasma concentration-time curve (AUC) following i.v. administration for three different doses ranging from 2.5 to 10 mg/kg.

Accommodation causes with-the-rule astigmatism in emmetropes

PURPOSE

To measure the changes in astigmatism when bilateral emmetropes accommodate.

METHODS

Bilateral emmetropes accommodative responses were measured with an improved photorefractometer PR-1100, which measured binocular refraction in all meridians simultaneously as a fixation target was shown in natural space.

RESULTS

The accommodative responses in the vertical meridian are greater than those in the horizontal meridian. In the horizontal meridian, the accommodative responses are less than the accommodative stimulus.

CONCLUSIONS

When accommodating the majority of bilateral emmetropes show with-the-rule astigmatism and lag of accommodation in the horizontal meridian.

Total elbow arthroplasty with use of a nonconstrained humeral component inserted without cement in patients who have rheumatoid arthritis

BACKGROUND

Most total elbow prostheses that are currently in use require cement for fixation of each component. We developed a new (type-5) prosthesis that does not need cement for fixation.

METHODS

The humeral component is made of cobalt-chromium alloy, and its stem is porous-coated with a plasma spray of titanium alloy. There are two options for the ulnar component: an all-polyethylene type and a metal-backed type with a porous-coated stem. Forty-three elbows in thirty-seven patients who had rheumatoid arthritis were treated with total elbow replacement arthroplasty with use of the type-5 prosthesis. The humeral component was implanted without cement in all elbows, whereas the ulnar component was implanted without cement in eleven elbows and was fixed with cement in the remaining thirty-two. The elbows were followed for an average of three years and ten months (range, two years and six months to five years and six months).

RESULTS

The clinical results were assessed according to a modification of the Mayo Clinic Performance Index. At the time of the latest follow-up, the overall result was excellent for six elbows, good for thirty-one, and fair for six. All elbows had been rated as poor before the operation. There was almost complete relief of pain in twenty-nine elbows and mild or occasional pain in the remaining fourteen. Flexion increased markedly, from an average of 104 degrees preoperatively to an average of 133 degrees postoperatively; this difference was highly significant (p < 0.001, Student t test). In contrast, extension (flexion contracture) worsened slightly, from an average of 38 degrees preoperatively to an average of 42 degrees postoperatively; this difference was significant (p < 0.05). There was one postoperative dislocation of the elbow, and ectopic bone formed in another, with recurrence of ankylosis. Both elbows had a reoperation, and a good result eventually was obtained. There were no instances of postoperative infection or neuropathy of the ulnar nerve. Radiographically, there were no radiolucent lines at the bone-metal interface of any of the humeral or ulnar stems that had been implanted without cement, suggesting solid fixation by osseointegration.

CONCLUSIONS

The results of total elbow arthroplasty with use of this prosthesis appear promising. There was a high rate of relief of pain as well as of restoration of adequate function in patients in whom the elbow was severely affected by rheumatoid arthritis.

GFR alpha3, a component of the artemin receptor, is required for migration and survival of the superior cervical ganglion

GFR alpha3 is a component of the receptor for the neurotrophic factor artemin. The role of GFR alpha3 in nervous system development was examined by generating mice in which the Gfr alpha3 gene was disrupted. The Gfr alpha3-/- mice exhibited severe defects in the superior cervical ganglion (SCG), whereas other ganglia appeared normal. SCG precursor cells in the mutant embryos failed to migrate to the correct position, and they subsequently failed to innervate the target organs. In wild-type embryos, Gfr alpha3 was expressed in migrating SCG precursors, and artemin was expressed in and near the SCG. After birth, SCG neurons in the mutant mice underwent progressive cell death. These observations suggest that GFR alpha3-mediated signaling is required both for the rostral migration of SCG precursors and for the survival of mature SCG neurons.

Transepithelial transport of organic anions across the choroid plexus: possible involvement of organic anion transporter and multidrug resistance-associated protein

Transport characteristics of 17beta-estradiol 17beta-D-glucuronide (E217betaG), a dual substrate of the transporters for cellular uptake (organic anion-transporting polypeptide 1 or oatp1) and cellular excretion (multidrug resistance-associated protein 1or MRP1), in the rat choroid plexus were studied in vivo and in vitro. The uptake of E217betaG into isolated choroid plexus was mediated by an energy-dependent system with a Km of 3.4 microM. Together with the previous finding that oatp1 is localized on the apical membrane of choroid plexus, these results suggest that oatp1 is responsible for the uptake of this ligand. After intracerebroventricular administration, elimination of E217betaG from cerebrospinal fluid was probenecid sensitive and much more rapid than that of inulin; less than 2% of the administered E217betaG and 40 to 50% of inulin remained in the cerebrospinal fluid 20 min after intracerebroventricular administration. In addition, the amount of E217betaG associated with choroid plexus at 20 min was negligible, suggesting the presence of an efficient excretion system on the basolateral membrane of choroid plexus. Expression of MRP1 was detected in choroid plexus. Semiquantitative reverse transcription-polymerase chain reaction and Western blot analyses indicated that the expression level of MRP1 in choroid plexus is about four or five times higher than that in the lung, one of the tissues exhibiting high expression of MRP1. Together with the in vivo vectorial transport of E217betaG, these results can be accounted for by assuming that there is basolateral localization of MRP1 in choroid plexus. Combined, oatp1 and MRP1 may synergistically mediate the efficient transcellular transport of E217betaG across choroid plexus.

Pharmacokinetics of pentazocine and its occupancy of opioid receptors in rat brain

In order to assess quantitatively the pharmacodynamic process of pentazocine (PTZ), time courses of its plasma concentration and of the occupation of specific opioid receptors in the brain were investigated after intravenous (i.v.) administration of PTZ to rats. The plasma concentration of PTZ was determined by HPLC and the pharmacokinetic parameters were analyzed using nonlinear least-squares analysis. Measurement of ex vivo receptor occupation was made by comparing the specific [3H]naloxone (opioid receptor antagonist) binding in vitro to the crude P2-synaptosomal fractions between vehicle-treated rats (control) and PTZ-treated rats. Following the i.v. administration of PTZ, the occupancy of specific opioid receptors decreased rapidly until 10 min, depending on the two pharmacological doses (2.5 and 10 mg/kg). The results strongly suggest the fast binding kinetics of PTZ in terms of its association with and dissociation from specific opioid receptor sites in the brain in addition to its fast rate of disappearance from the brain compartment. Furthermore, we demonstrated that the time profile of receptor occupancy correlated well (r = 0.8650) with that of the unbound concentration in plasma until 120 min after the i.v. administration of PTZ to rats.

An anomalous side reaction of the Lys303 mutant aromatic L-amino acid decarboxylase unravels the role of the residue in catalysis

Aromatic L-amino acid decarboxylase (AADC) in which the pyridoxal 5'-phosphate (PLP)-binding residue Lys303 was replaced by an alanine residue is virtually inactive as a catalyst. On reaction of the normal substrate L-dopa with this mutant AADC, the absorption at around 330 nm gradually increased with concomitant decrease of the absorption of the free PLP molecule at 390 nm. Analysis of the 330-nm absorbing species on HPLC and spectrophotometry showed that it is a 1:1 adduct of PLP and dopamine, probably the Pictet-Spengler type adduct formed from the PLP-dopamine Schiff base. The product dopamine was not found outside of the enzyme, showing that the PLP-dopamine Schiff base undergoes adduct formation rather than yields product dopamine. The Pictet-Spengler adduct of PLP with L-dopa was not detected, whereas the corresponding adduct was formed when the carboxylate group of L-dopa was esterified with a methyl group to block the decarboxylation reaction. This suggests that the PLP-L-dopa Schiff base may undergo the Pictet-Spengler reaction, but its rate is much smaller than that of decarboxylation. These results indicate that Lys303 is not essential for the decarboxylation step, but has an important role in the product release, and possibly the transaldimination process.

Functionally important residues of aromatic L-amino acid decarboxylase probed by sequence alignment and site-directed mutagenesis

To identify functional residues of rat liver L-aromatic amino acid decarboxylase (AADC), we aligned the sequences of 13 group II amino acid decarboxylases and performed mutational analysis on the residues that were invariant or conservatively substituted. Replacements of His192, Asp252, Asp271, Ser296, Lys303, Tyr332, and Arg355 with alanine residues decreased the AADC activity (kcat/K(m)) by more than 10(4)-fold. Conservative replacements of [Asp252-->Glu], [Lys303-->Arg], and [Tyr332-->Phe] also resulted in decreases in activity by more than 10(4)-fold, indicating that both the chemical properties and the shape of these residues are essential for catalysis. The presence of a Schiff base between the amino group of Lys303 and the coenzyme pyridoxal 5'-phosphate is important for catalysis, probably at the transaldimination step. The enzyme activity was essentially unaffected by conservative mutation of [Arg355-->Lys], showing that the presence of a basic group at position 355 is necessary and sufficient for the catalysis. Replacement of [Thr246-->Ala], [His269-->Ala], and [Trp363-->Leu] yielded mutant enzymes that were 1-8% as active as the wild-type enzyme; these residues are not essential for the catalysis but are considered to contribute to the activity through conformational or other effects. The roles of the catalytically important residues of the group II amino acid decarboxylases probed in this study were discussed in the light of their relationship with the residues of other pyridoxal enzymes.

Cementless or hybrid total elbow arthroplasty with titanium-alloy implants. A study of interim clinical results and specific complications

Twenty-six patients (32 elbows) with rheumatoid arthritis had a total elbow arthroplasty with insertion of a cementless prosthesis. The humeral component was made of titanium alloy and it was fixed without cement in all elbows. The patients were followed for an average of 3 years 1 month (range, 2 years 2 months to 4 years 4 months). A good result was seen in 25 elbows, a fair result in 2, and a poor result in 5. The reason for the poor results was a breakage of the humeral component at the junctional portion of its stem. In all five of these elbows a marked resorption of bone mass within the condylar portion of the humeral component was observed on the lateral radiograph. The five elbows with a poor result had a revision operation, and in each of these black staining of the soft tissues within the joint was seen. This tissue metallosis due to wear debris of the titanium alloy was responsible for the osteolysis within the condylar portion. It became clear from this study that even in a non-weight-bearing joint, such as the elbow, titanium alloy may wear and result in tissue metallosis when used as a bearing surface of the implant. However, it was also found that in the majority of the elbows an establishment of the biologic fixation of the porous-coated stem could be achieved by use of this alloy.

Fibroblast attachment to Arg-Gly-Asp peptide-immobilized poly(gamma-methyl L-glutamate)

The attachment of MRC-5 human fibroblasts was investigated on poly(gamma-methyl L-glutamate) (PMLG), and upon cell adhesion peptides Arg-Gly-Asp-Ser (RGDS)- and Gly-Arg-Gly-Asp-Ser (GRGDS)-immobilized PMLG (RGDS-PMLG and GRGDS-PMLG). The peptides were immobilized by their N-terminal amine to activated PMLG surfaces. Prior to peptide immobilization, the aminolysis of PMLG surfaces was performed with hydrazine hydrate (HA), ethylenediamine (EDA), and hexamethylenediamine (HMDA) and was followed by the activation with hexamethylene diisocyanate. Surface characterization of these films was carried out by means of a Fourier transform IR (FT-IR) spectrometer equipped with an attenuated total reflectance (ATR) attachment. The amount of immobilized RGDS could be controlled by the reaction time of the aminolysis. The effects of HA, EDA, and HMDA as a spacer on the cell attachment were also investigated, and it was suggested that a longer spacer promoted the cell attachment via specific receptor-ligand interaction.

A novel class of enkephalinase inhibitors containing a C-terminal sulfo group

A new series of sulfonic acids were synthesized and tested for their enkephalinase inhibitory activity. Among them, the most potent was N-(2-benzyl-3-mercaptopropionyl)metanilic acid 10i with an IC50 value of 0.27 nM. Several other analogues (10a,b,j,n,o,gg,hh) showed the inhibitory activity comparable to or greater than thiorphan (IC50 = 2.6 nM), a C-terminal carboxyl-containing inhibitor of enkephalinase. Thus compounds containing a C-terminal sulfo group, instead of the C-terminal carboxyl group, were found to show a remarkably high level of inhibition of enkephalinase. The analgesic activity of 10b, (S)-10b, and (R)-10b was also evaluated by the phenylbenzoquinone writhing test.

Meniscal suture. An experimental study in the dog

A longitudinal tear was made and then sutured in the peripheral quarter of the medial meniscus of 43 dogs. The sutured menisci were examined using histologic and microangiographic techniques at regular intervals during a 12-week period. Biomechanical tests were also performed. The healing process was promoted not only by the synovial blood supply but also by the peripheral blood supply. Even at the end of 12 weeks, the healing tissue was mainly composed of fibrous tissue, but chondrocytelike cells were also found. The tensile forces were calculated and compared with the opposite leg. The maximum tensile strength reached 80% of that of the opposite side at the end of the 12-week period.