Do screws and screw holes affect osteolysis in cementless cups using highly crosslinked polyethylene? A 7 to 10-year follow-up case-control study.

BACKGROUND: The use of screws and the presence of screw holes may cause acetabular osteolysis and implant loosening in cementless total hip arthroplasty (THA) using conventional polyethylene. In contrast, this issue is not fully understood using highly crosslinked polyethylene (HXLPE), particularly in large comparative study. Therefore, we performed a case-control study to assess the influence of screw usage and screw holes on: (1) implant fixation and osteolysis and (2) polyethylene steady-state wear rate, using cases with HXLPE liners followed up for 7-10 years postoperatively. HYPOTHESIS: The screw usage and screw holes adversely affect the implant fixation and incidence of wear-related osteolysis in THA with HXLPE. PATIENTS AND METHODS: We reviewed 209 primary cementless THAs performed with 26-mm cobalt-chromium heads on HXLPE liners. To compare the effects of the use of screws and the presence of screw holes, the following groups were established: (1) with-screw (n=140); (2) without-screw (n=69); (3) no-hole (n=27) and (4) group in which a cup with screw holes, but no screw was used (n=42). Two adjunct groups (no-hole cups excluded) were established to compare the differences in the two types of HXLPE: (5) remelted group (n=100) and (6) annealed group (n=82). Implant stability and osteolysis were evaluated by plain radiography and computed tomography. The wear rate from 1 year to the final evaluation was measured using plain X-rays and PolyWare Digital software. RESULTS: All cups and stems achieved bony fixation. On CT-scan, no acetabular osteolysis was found, but there were 3 cases with a small area of femoral osteolysis. The mean steady-state wear rate of each group was (1) 0.031±0.022, (2) 0.033±0.035, (3) 0.031±0.024, (4) 0.029±0.018, (5) 0.030±0.018 and (6) 0.034±0.023mm/year, respectively. A comparison of the effects of screw usage or screw holes found no significant between-group differences in the implant stability, prevalence of osteolysis [no acetabular osteolysis and 3/209 at femoral side (1.4%)] and steady-state wear rate. DISCUSSION: This study suggests that there are no adverse effects on the results of THA with HXLPE from the use of cups with screw holes and the use of screws for cup fixation. LEVEL OF EVIDENCE: Level III retrospective case-control study.

Proteolytic processing yields two secreted forms of sonic hedgehog.

Sonic hedgehog (Shh) is expressed in tissues with known signalling capacities, such as the notochord, the floor plate of the central nervous system, and the zone of polarizing activity in the limb. Several lines of evidence indicate that Shh is involved in floor plate induction, somite patterning, and regulation of anterior-posterior polarity in the vertebrate limb. In this report, we investigate the biochemical behavior of Shh in a variety of expression systems and embryonic tissues. Expression of mouse Shh in Xenopus oocytes, COS cells, and baculovirus-infected insect cells demonstrates that in addition to signal peptide cleavage and N-linked glycosylation, chicken and mouse Shh proteins undergo additional proteolytic processing to yield two peptides with molecular masses of approximately 19 kDa (amino terminus) and 27 kDa (carboxy terminus), both of which are secreted. In transfected COS cells, we show that the 19-kDa peptide does not accumulate significantly in the medium unless heparin or suramin is added, suggesting that this peptide associates with the cell surface or extracellular matrix. This retention appears to depend on sequences in the carboxy-terminal part of the peptide. Finally, detection of the 19-kDa product in a variety of mouse and chicken embryonic tissues demonstrates that the proteolytic processing observed in cell culture is a normal aspect of Shh processing in embryonic development. These results raise the possibility that amino- and carboxyl-terminal regions of Shh may have distinct functions in regulating cell-cell interactions in the vertebrate embryo.

Molecular cloning, expression, and characterization of the Drosophila 85-kilodalton TFIID subunit.

Transcription initiation factor TFIID is a multimeric protein complex that plays a central role in mediating promoter responses to various activators and repressors. To further understand the role of the 85-kDa TFIID subunit (p85), we have cloned the corresponding cDNA with a probe based on an amino acid sequence of the purified protein. The recombinant p85 interacts directly with both the TATA box-binding subunit (TFIID tau or TBP) and the 110-kDa subunit (p110) of TFIID, suggesting that p85 may play a role in helping to anchor p110 within the TFIID complex and, with other studies, that TFIID assembly and function may involve a concerted series of subunit interactions. Interestingly, the carboxy terminus of p85 contains eight of the WD-40 repeats found originally in the beta subunit of G proteins and more recently in other transcriptional regulatory factors. However, truncated p85 lacking all the WD-40 repeats maintained interactions with both TFIID tau and p110. These observations leave open the possibility of a distinct function for the WD-40 repeats, possibly in transducing signals by interactions with transcriptional regulators and/or other components of the basic transcriptional machinery.

Comparison of wear rate and osteolysis between second-generation annealed and first-generation remelted highly cross-linked polyethylene in total hip arthroplasty. A case control study at a minimum of five years.

BACKGROUND: There is no previous report that directly compared wear resistance of second-generation annealed highly cross-linked polyethylene with that of first-generation remelted highly cross-linked polyethylene. We therefore performed a retrospective study at a minimum of 5-year follow-up comparing second-generation annealed and first-generation remelted highly cross-linked polyethylene in order to: (1) assess wear rates and (2) compare the incidence of osteolysis between, (3) identify the frequency of complication related to the two types of highly cross-linked polyethylene. HYPOTHESIS: There is a difference in the linear wear rate and the incidence of osteolysis between the two types of highly cross-linked polyethylene in total hip arthroplasty. MATERIALS AND METHODS: In a single centre study, we reviewed 123 primary cementless total hip arthroplasties between 2010 and 2011 that were performed with 32mm alumina ceramic on second-generation annealed (X3) or first-generation remelted (Longevity) highly cross-linked polyethylene liner. There was no specific reason for the choice of the type of highly cross-linked polyethylene. There were no significant differences between the two groups in respect of gender, diagnosis, body mass index, pre- and post-operative functional and activity score, cup size, and cup orientation except the younger age in the X3 group. The mean wear rate and the incidence of osteolysis were evaluated at the latest follow-up. RESULTS: One hundred nine cases followed over 5 years post-operatively (88.6% in all consecutive cases) were evaluated. X3 and Longevity were used in 54 and 55 cases, respectively. The mean follow-up was 5.3 years in both groups. The mean linear wear rate of X3 and Longevity group was 0.045±0.023mm/year and 0.076±0.031mm/year, respectively (P<0.001). No osteolysis was found on plain X-rays in both groups and no specific complication was related to these highly cross-linked components. DISCUSSION: Excellent wear resistance of both types of highly cross-linked polyethylene liner was revealed in our study. The difference of wear rate between two materials should be monitored in a longer follow-up. LEVEL OF EVIDENCE: Level III retrospective case control study.

Comparison of wear rate and osteolysis between annealed and remelted highly cross-linked polyethylene in total hip arthroplasty. A case control study at 7 to 10 years follow-up.

BACKGROUND: Low polyethylene wear rate and low incidence of osteolysis after total hip arthroplasty using annealed and remelted highly cross-linked polyethylene have been reported. However, there is no previous report that directly compared both types of highly cross-linked polyethylene. We therefore performed a retrospective study on a series of highly cross-linked polyethylene, in order to: (1) compare wear rates and the incidence of osteolysis between annealed and remelted highly cross-linked polyethylene at 7-10 years; (2) identify the frequency of complication related to annealed and remelted highly cross-linked polyethylene. HYPOTHESIS: There is no difference in the linear wear rate and the incidence of osteolysis between the annealed and remelted highly cross-linked polyethylene in total hip arthroplasty. PATIENTS AND METHODS: Two hundred and sixteen cases of cementless total hip arthroplasties with annealed or remelted highly cross-linked polyethylene, which were performed between January 2003 and December 2006 in one institution, were followed for 7-10 years and received computed tomography scan, in addition to radiography at the latest follow-up. Annealed and remelted highly cross-linked polyethylene was used in 91 cases and 125 cases, respectively. A 26-mm cobalt-chromium head was used in all cases. Penetration rates from 1 year to the last evaluation were used to estimate the yearly linear wear rate. Existence of osteolysis was evaluated by plain radiography and computed tomography. RESULTS: There were no significant differences in patients' background between the two groups. The linear wear rate of annealed and remelted group was 0.031±0.022mm/year and 0.032±0.020mm/year, respectively (P=0.91). Two cases of small femoral osteolysis were found in the annealed group. Any complication related to highly cross-linked polyethylene was not found in both groups. DISCUSSION: There was no significant difference in the linear wear rate and the incidence of osteolysis between the annealed and remelted group at postoperative 7 to 10 years. Excellent results of both types of highly cross-linked polyethylene were revealed by this study. LEVEL OF EVIDENCE: Level III retrospective case control study.

Axin prevents Wnt-3a-induced accumulation of beta-catenin.

When Axin, a negative regulator of the Wnt signaling pathway, was expressed in COS cells, it coeluted with glycogen synthase kinase-3beta (GSK-3beta), beta-catenin, and adenomatous polyposis coli protein (APC) in a high molecular weight fraction on gel filtration column chromatography. In this fraction, GSK-3beta, beta-catenin, and APC were co-precipitated with Axin. Although beta-catenin was detected in the high molecular weight fraction in L cells on gel filtration column chromatography, addition of conditioned medium expressing Wnt-3a to the cells increased beta-catenin in the low molecular weight fraction. However, Wnt-3a-dependent accumulation of beta-catenin was greatly inhibited in L cells stably expressing Axin. Axin also suppressed Wnt-3a-dependent activation of Tcf-4 which binds to beta-catenin and acts as a transcription factor. These results suggest that Axin forms a complex with GSK-3beta, beta-catenin, and APC, resulting in the stimulation of the degradation of beta-catenin and that Wnt-3a induces the dissociation of beta-catenin from the Axin complex and accumulates beta-catenin.

Waveform changes of the first-order multifocal electroretinogram in patients with glaucoma.

PURPOSE: To investigate the relationship between the components of the first-order multifocal electroretinogram (M-ERG) and glaucomatous visual field loss. METHODS: Twenty-six eyes of 14 patients with primary open-angle glaucoma (POAG) were evaluated with the M-ERG techniques. Twenty-six eyes of 26 normal subjects also were tested as control subjects. To record the M-ERG, a stimulus matrix of 103 scaled hexagonal elements was displayed on a monitor driven at a 75-Hz frame rate according to a binary m-sequence. The M-ERG responses were averaged in each quadrant of the stimulus field and the peak-to-trough amplitudes and peak implicit times of the first trough (N1), the first peak (P1), and the second trough (N2) of the M-ERG were compared with the mean sensitivity values (dB) of the corresponding quadrant of the Humphrey static perimetric field. RESULTS: The changes in the peak latencies of P1 and N2 in the POAG group were small but significant compared with those in the normal group (P < 0.01). However, no significant differences in the amplitudes of (P1-N1) and (P1-N2) between the two groups were found. Significant negative correlations between the peak implicit times of N1, P1, and N2 and the mean sensitivity values (dB) of static perimetry were observed. The correlation coefficients were -0.20 (P < 0.05) for the N1, -0.41 (P < 0.001) for the P1, and -0.59 (P < 0.001) for the N2. No significant correlations were observed between the amplitudes (P1-N1 and P1-N2) and the mean sensitivity values. CONCLUSIONS: The present study findings suggest that the peak implicit times, but not the amplitudes, of the M-ERG increase as the glaucomatous visual field deteriorates. The amplitudes of the M-ERG did not decrease as the glaucomatous optic nerve dysfunction progressed.

Ethanol dissociates thiopental and GABA-receptor interaction.

The effect of ethanol on thiopental and GABA-receptor interaction was studied in hippocampal slice preparations and membrane fractions. The field potentials evoked in pyramidal neurons by stratum radiatum stimulation are inhibited by GABA 10(?4)-10(?3) M. Thiopental, 10(?5) M, enhanced the inhibitory effect. When ethanol, 35 mM, was included, no enhancement of GABA inhibition of the field potentials by thiopental was observed. This effect of ethanol was reversible. The dissociative effect of ethanol on thiopental and GABA-receptor interaction was observed also in [(3)H]GABA binding experiments. In slices from rats chronically administered ethanol (2 g/kg, b.i.d., 30 days), thiopental was without effect on GABA inhibition of the field potentials. The results are discussed in relation to phenomena underlying chronic barbiturate or ethanol intoxication.

Effect of thiopental on hippocampal GABA receptors in rat brain.

The effect of thiopental on rat brain hippocampal GABA receptors was studied in slice preparations and membrane fractions. In slice preparations, thiopental at a concentration of 10(?5) M enhanced the GABA (1?5 x 10(?4)M) inhibition of the field potentials evoked in pyramidal neurons by stratum radiatum stimulation. In hippocampal slices obtained from chronically barbital-administered (100 mg/kg, b.i.d., 10 days) rats, less enhancement of thiopental on GABA inhibition of the field potentials was observed. In binding experiments, two components of specific [(3)H]GABA binding to membrane fractions were observed. While thiopental was without effect on high-affinity sites, [(3)H]GABA binding with low affinity was enhanced by 80% in the presence of 10(?5) M thiopental. The results are discussed in relation to the phenomena underlying chronic barbiturate administration.

Effects of localized lesions in the lateral suprasylvian cortex on convergence eye movement in cats.

We evaluated the effects of electrolytic lesions in the extrastriate cortical area on the amplitudes and velocities of vergence eye movements in six alert cats that were trained to track a target moving in depth. Bilateral or unilateral lesions in the lateral suprasylvian (LS) cortex reduced the amplitudes and velocities of vergence eye movements, but the positive correlation between them was maintained. Furthermore, unilateral lesions changed the symmetry of eye movements. Movements of the left eye were decreased by lesions in the right LS cortex, resulting in asymmetric vergence eye movement with right eye predominance, and vice versa. These results support the hypothesis that the LS cortex plays an essential role in controlling vergence eye movement.

Coordinate induction of peroxisomal acyl-CoA oxidase and UCP-3 by dietary fish oil: a mechanism for decreased body fat deposition.

Rats fed dietary fats rich in 20- and 22-carbon polyenoic fatty acids deposit less fat and expend more energy at rest than rats fed other types of fats. We hypothesized that this decrease in energetic efficiency was the product of: (a) enhanced peroxisomal fatty acid oxidation and/or (b) the up-regulation of genes encoding proteins that were involved with enhanced heat production, i.e. mitochondrial uncoupling proteins (UCP-2, UCP-3) and peroxisomal fatty acid oxidation proteins. Two groups of male Fisher 344 rats 3-4 week old (n=5 per group) were pair fed for 6 weeks a diet containing 40% of its energy fat derived from either fish oil or corn oil. Epididymal fat pads from rats fed the fish oil diet weighed 25% (P < 0.05) less than those found in rats fed corn oil. The decrease in fat deposition associated with fish oil ingestion was accompanied by a significant increase in the abundance of skeletal muscle UCP-3 mRNA. The level of UCP-2 mRNA skeletal muscle was unaffected by the type of dietary oil, but the abundance of UCP-2 mRNA in the liver and heart were significantly lower (P < 0.05) in rats fed fish oil than in rats fed corn oil. In addition to inducing UCP-3 expression, dietary fish oil induced peroxisomal acyl-CoA oxidase gene expression 2-3 fold in liver, skeletal muscle and heart. These data support the hypothesis that dietary fish oil reduces fat deposition by increasing the expression of mitochondrial uncoupling proteins and increasing fatty acid oxidation by the less efficient peroxisomal pathway.

Studies on protein binding of antibiotics. I. Effect of cefazolin on protein binding and pharmacokinetics of cefoperazone.

The effect of cefazolin (CEZ) on the protein binding and the pharmacokinetics of cefoperazone (T-1551) was investigated. For the simultaneous determination of T-1551 and CEZ, high pressure liquid chromatography (HPLC) was used. The extent of protein binding, the number of binding sites and the association constant to human serum albumin were 90.4%, 0.87 and 2.16 X 10(4) in T-1551, and 89.2%, 0.78 and 2.46 X 10(4) in CEZ, respectively. T-1551 and CEZ appeared to bind to the same site on the protein, since each drug competitively inhibited the binding of the other to serum protein. The mode of the binding of T-1551 to serum protein was similar to that of CEZ. When T-1551 and CEZ were co-administered, the serum level of T-1551 was lower than that with the single administration, while, urinary excretion was higher. These results suggested that the concomitantly administered drugs influenced one another's binding to serum protein in vivo and subsequently an increase in the concentration of the unbound drug in the serum made the drug available for glomerular filtration. It seemed that the high protein binding of T-1551 to serum was an important factor affecting its pharmacokinetics.

Effect of ethanol on hippocampal GABA receptors in the rat brain.

The effect of ethanol on GABA receptors was studied in hippocampal slices and membrane preparations of the rat brain. In slice preparation, ethanol enhanced the GABA inhibition of the population spikes evoked in CA 1 pyramidal cells by Schaffer collateral stimulation. The effect of ethanol was dose-dependent being observed with minimal concentration of 70 mM. In 3H-GABA binding experiments, ethanol enhanced the binding to fresh membranes with no change in the affinity. Maximal stimulation was observed at ethanol concentration of 70 mM. In hippocampal slices or membrane preparations obtained from ethanol- or barbital-administered rats chronically, ethanol failed to enhance GABA function. Thus, the present study demonstrated the involvement of GABA in central effect of ethanol. Also suggested in GABA was the involvement in the development of cross-tolerance between ethanol and barbiturates.

Antibodies specific to outer membrane antigens of Moraxella catarrhalis in sera and middle ear effusions from children with otitis media with effusion.

OBJECTIVE: Recent studies have shown that bacterial DNA is present in a significant percentage of middle ear effusions, suggesting that persistent bacterial infection may be more important in pathogenesis and recurrence of otitis media with effusion (OME) than previously considered. Although Moraxella (M.) catarrhalis is one of the most common pathogens of otitis media, relatively little is known about immune response to the organism. The objective of the present study is to investigate how systemic and local immune activities against M. catarrhalis may be associated with severity of OME. METHODS: The antibody levels specific to outer membrane antigens of M. catarrhalis in sera and middle ear effusions (MEEs) from 59 children with OME were measured by enzyme-linked immunosorbent assay. Their ages ranged from 1 to 12 years with a median 5.0 years. The children were followed 1 year prospectively and classified into two groups with or without recurrent/persistent OME according to severity of OME during the follow-up 1 year. RESULTS: Serum IgG, IgM, and IgA antibodies specific to outer membrane antigens of M. catarrhalis were detected in all samples and the median levels were 35, 0.93, and 1.2 microg/ml respectively. The MEE IgG, IgM, IgA, and secretory IgA antibodies were detected in over 95% samples tested and the median levels were 371, 158, 20, and 50 ng/mg total protein respectively. A comparison between acute and subacute/chronic phases revealed that the median levels of MEE IgG and IgM antibodies were higher at the acute phase (692 vs. 340, P = 0.06; 35 vs. 10, P = 0.02, respectively); while the MEE secretory IgA antibody level was increased at the subacute/chronic phase (74 vs. 35, P = 0.02). Either serum or MEE IgG antibody level was significantly lower in recurrent/persistent OME group than that in nonrecurrent/non-persistent OME group (13 vs. 43 ,microg/ml, P = 0.009; 238 vs. 577 ng/mg protein, P = 0.006, respectively). CONCLUSIONS: These data provide additional information on the immunologic aspects of children with OME. Decreased serum and MEE IgG antibody levels specific to outer membrane antigens of M. catarrhalis may lead to failure to eliminate this organism, resulting in persistent and/or recurrent appearance of MEE.

Multifocal electroretinograms in patients with branch retinal artery occlusion.

PURPOSE: We recorded multifocal electroretinograms (M-ERG) in patients with branch retinal artery occlusion (BRAO) and compared the waveforms in the area of retinal artery occlusion with those in the normal area, to evaluate the influence of the damage to the inner retina shown by M-ERG responses. METHODS: Three patients who had normal visual acuity and visual field loss of more than one quadrant due to BRAO were examined. The central 50 degrees of ocular fundus was stimulated through dilated pupils by an array of 103 hexagonal elements for 4 minutes. The waveforms of the first order and second order kernel responses of M-ERG in the area of the retinal artery occlusion were compared with those of the vertically symmetrical, normally perfused area of the same eye. RESULTS: The amplitude of the averaged tracing decreased in the first negative wave (N1), first positive wave (P1), and second negative wave (N2) in the first order kernel responses in the area of retinal artery occlusion in comparison with the normally perfused area. Furthermore, prolongation of latency was noted for N1, P1, and N2 in the same area. Second order kernel responses were not detected in the area of the retinal artery occlusion. CONCLUSIONS: The damage to the inner retina affected parts of N1, P1, and N2 of the first order kernel responses, with N2 being the most seriously affected. Furthermore, second order kernel responses clearly reflected the condition of the inner retina.

[Multifocal electroretinograms in patients with branch retinal artery occlusion].

PURPOSE: We recorded multifocal electroretinograms (m-ERGs) in patients with branch retinal artery occlusion (BRAO) and compared the waveform in the area of retinal artery occlusion with that in the normal area, to evaluate the influence of the damage of the inner retina on the m-ERG. SUBJECTS AND METHODS: Three patients who had normal visual acuity and visual field loss of more than one quadrant due to BRAO were examined. The waveform of first-order and second-order kernel responses of m-ERG in the area of retinal artery occlusion were compared with those of the vertically symmetrical, normally perfused area of the same eye. RESULTS: Prolongation of latency and decrease of amplitude were noted for the first negative wave (N 1), the first positive wave (P1), and the second negative wave (N2) in the first-order kernel responses in the area of retinal artery occlusion in comparison with the normally perfused area. Second-order kernel responses were not detected in the area of retinal artery occlusion. CONCLUSIONS: The damage to the inner retina affected portions N1, P1, and N2 of the first-order kernel responses, and N2 was the most seriously affected. Second-order kernel responses appear to reflect more strongly the function of the inner retina.

[Multifocal electroretinogram in central serous chorioretinopathy].

PURPOSE: To assess retinal function topographically in the affected eyes with central serous chorioretinopathy (CSC). PARTICIPANTS AND METHOD: We recorded multifocal electroretimogram (mERG) in 5 patients with unilateral CSC, and analyzed the topographical properties in the central visual field (rings #1 + 2). RESULTS: mERG amplitudes in the CSC eyes were significantly reduced compared with the fellow eyes, for P 1-N 1 (58.5 +/- 23.5%, p < 0.05) and for P 1-N 2 (47.5 +/- 15.0%, p < 0.05). mERG latencies in the CSC eyes were significantly increased compared with those in the fellow eyes, for N 1 (by 9.0 +/- 8.1%, p < 0.05) and for P 1 (by 8.4 +/- 7.0%, p < 0.05). mERGs in the CSC eyes gradually recovered in the follow-up period. However, the responses did not recover to normal value during follow-up, even when the subretinal fluid disappeared ophthalmoscopically. CONCLUSIONS: These results show that a topographical analysis of the mERG is useful for clinical observation of CSC.

[Quantitative evaluation of nystagmus by an image-analysis system].

PURPOSE: We attempted to apply a newly developed image-analysis system for measurement and analysis of nystagmus. METHOD: Eye movements were recorded by digital video through a head-mounted charge coupled device (CCD) camera. The recorded movie was converted into black and white in order to detect the area of the pupil. Horizontal and vertical eye positions were determined by calculating the centroid of the pupil. Torsional angle was calculated using the iris striate pattern around the pupillary margin. RESULTS: The parameters (amplitude, cycle, etc.) of nystagmus were calculated easily by the new image-analysis system from the recorded images. As examples, the foveation period was measured accurately in a case of jerky-type congenital nystagmus. Very regular cycles of intorsional attack period were revealed in a case of superior oblique myokymia. A case of cork-screw-like nystagmus showed a characteristic combination of large and small cycles unassociated with torsion. CONCLUSION: This image-analysis system was useful for quantitative analysis of nystagmus, and especially for measurement of torsion. Detailed waveforms and specific rhythms of nystagmus, which could not be recognized by observation, were demonstrated by this system.

[Detection of isotype-specific autoantibodies to calpastatin in sera from patients with rheumatic diseases using heat-treated HeLa cell extract as an antigen source for immunoblotting].

To detect immunoglobulin isotype-specific autoantibodies to native human calpastatin in patients with rheumatic diseases, we performed immunoblot analysis using the heated HeLa cell extracts to enrich heat-resistant calpastatin. The calpastatin molecule that was apparently migrated to 110 kD by SDS-PAGE was confirmed to react with monoclonal anti-human calpastatin antibody in immunoblotting. IgG antibodies to calpastatin were detected in 22 of 48 sera (46%) from patients with RA, whereas only 20% (5/25), 11% (2/19) and 13% (2/15) of sera from SLE, SSc and PM/DM had IgG anti-calpastatin antibodies, respectively. IgM antibodies were also found in 40% (19/48) of RA and 12% (3/25) of SLE patients but not detected in sera from patients with other rheumatic diseases. IgA antibodies were found in only one RA and one SLE serum. In RA, 7 of 48 sera (15%) had IgM antibodies alone, but all SLE sera with IgM antibodies had IgG antibodies. Thus, anti-calpastatin autoantibodies were detected by using the native human calpastatin. Although these autoantibodies were found in patients with various rheumatic diseases, they were present in RA patients at the highest frequency. In particular, the presence of IgM antibodies appeared to be more specific in RA patients.