Quantitative analysis of P16 gene CpG methylation in Uyghur patients with cervical squamous cell carcinoma and its relationship with HPV16 infection.

The methylation of CpG sites in the promoter region of the P16 gene in Uyghur patients with cervical squamous cell carcinoma (CSCC) was quantitatively analyzed and its relationship with human papillomavirus 16 (HPV16) infection was explored. Cervical samples were collected from 20 Uyghur patients with CSCC and 20 Uyghur controls. Matrix-assisted laser desorption ionization-time of flight mass spectrometry was applied to detect methylation of CpG sites in the promoter region of the P16 gene; polymerase chain reaction was performed to assess HPV16 infection in the 2 groups. Among the 16 CpG sites in the P16 gene promoter region, the methylation level of the CpG1-2 and CpG 6 sites, as well as the HPV16 infection rate, was higher in the CSCC group than in the control group (P<0.05). There was no significant correlation between P16 CpG methylation and HPV16 infection in Uyghur patients with CSCC. The P16 gene CpG1-2 and CpG 6 hypermethylation and HPV16 infection, which are independent of each other, play an important role in cervical squamous cell carcinogenesis in Uyghur patients.

[Genotype distribution and behavioral risk factor analysis of human papillomavirus infection among Kazak women in Xinjiang Uygur Autonomous Region].

Objective: To investigate the prevalence and genotype distribution of high-risk human papillomavirus (HR-HPV) and the correlation between cervical lesions and analyze the risk factors for HR-HPV infection. Methods: In June 2018, a population-based study for cervical cancer screening in Tuoli county of Xinjiang Uygur Autonomous Region was conducted. A total of 2 000 Kazak women aged 25-64 years were included in the study. Three cervical exfoliated cells samples were collected from them for careHPV, PCR HPV, p16(INK4a), and liquid-based cytology (LBC) tests. Women with any positive test were referred for colposcopy with biopsies taken at abnormal sites. Histo-pathological diagnoses were used as the gold standard. Results: The overall prevalence of HPV was 14.55%, among which the infection rate of HR-HPV was 12.90%, which was even higher in the 50-54 years age group. The most prevalent genotypes of HR-HPV were HPV16 (2.80%), HPV51(2.35%), HPV52 (1.70%), HPV56 (1.50%), and HPV39 (1.20%). The most common HPV infection was a single infection (71.48%). In the age group of 50-54 years, the multiple infection rates were higher, with the majority of double infection (69.88%), and HPV42 and 56 were the most common co-infection types. HPV16 (31.82%), HPV51 (27.27%) and HPV18 (13.64%) were higher in cervical intraepithelial neplasia grade 1, HPV16 (57.14%) was higher in cervical intraepithelial neplasia grade 2, and HPV16 (55.56%) and HPV18 (33.33%) were higher in cervical intraepithelial neplasia grade 3 or worse. Results from the multivariate logistic regression analysis showed that higher education, menopause, and syphilis infection increased the HPV infection. Conclusions: The most common prevalence genotypes of HR-HPV among Kazak women were HPV16, HPV51, and HPV52. The infection rate of HR-HPV among Kazak women was correlated with education level, menopausal status, and syphilis infection. Measures should be taken targeting high-risk factors. This result suggests that STD patients and women aged 50 and above should be encouraged for screening.

[Survey on Toxoplasma gondii infections among three types of populations in Wuxi City].

OBJECTIVE: To investigate the seroprevalence of Toxoplasma gondii infections among patients with rheumatoid arthritis, malignant tumors and schizophrenia in Wuxi City, so as to provide data support for the control of toxoplasmosis in these patients. METHODS: A total of 205 cases with definitive diagnosis of rheumatoid arthritis, 257 cases with definitive diagnosis of malignant tumors and 235 cases with definitive diagnosis of schizophrenia were recruited, while 250 healthy volunteers served as controls. The demographic features were captured from the study subjects and serum samples were collected. The serum IgG and IgM antibodies against T. gondii were detected using an enzyme-linked immunosorbent assay (ELISA) in all study subjects, and the positive rates of anti-T. gondii IgG and IgM antibodies were compared between the patients and controls. RESULTS: The seroprevalence of the anti-T. gondii IgG antibody was 20.98%, 24.12% and 24.68% in patients with rheumatoid arthritis, malignant tumors and schizophrenia, which were all significantly greater than in healthy controls (χ2 = 31.54, 42.12 and 42.98, all P values < 0.01), and the seroprevalence of the anti - T. gondii IgM antibody was 1.46%, 2.72% and 1.70% among patients with rheumatoid arthritis, malignant tumors and schizophrenia, which were all significantly higher than in healthy controls (χ2 = 0.06, 1.52 and 0.21, all P values > 0.05). CONCLUSIONS: The patients with rheumatoid arthritis, malignant tumors and schizophrenia present with higher seroprevalence of the anti-T. gondii IgG antibody than healthy controls in Wuxi regions. Screening of T. gondii infections among the patients with rheumatoid arthritis, malignant tumors and schizophrenia should be intensified to prevent the damages caused by T. gondii infections.

A calpain-10 gene polymorphism is associated with reduced muscle mRNA levels and insulin resistance.

Previous linkage studies in Mexican-Americans localized a major susceptibility locus for type 2 diabetes, NIDDM1, to chromosome 2q. This evidence for linkage to type 2 diabetes was recently found to be associated with a common G-->A polymorphism (UCSNP-43) within the CAPN10 gene. The at-risk genotype was homozygous for the UCSNP-43 G allele. In the present study among Pima Indians, the UCSNP-43 G/G genotype was not associated with an increased prevalence of type 2 diabetes. However, Pima Indians with normal glucose tolerance, who have a G/G genotype at UCSNP-43, were found to have decreased rates of postabsorptive and insulin-stimulated glucose turnover that appear to result from decreased rates of glucose oxidation. In addition, G/G homozygotes were found to have reduced CAPN10 mRNA expression in their skeletal muscle. A decreased rate of insulin-mediated glucose turnover, or insulin resistance, is one mechanism by which the polymorphism in CAPN10 may increase susceptibility to type 2 diabetes mellitus in older persons.

Mapping a new genetic locus for X linked retinitis pigmentosa to Xq28.

We have defined a new genetic locus for an X linked form of retinitis pigmentosa (RP) on chromosome Xq28. We examined 15 members of a family in which RP appeared to be transmitted in an X linked manner. Ocular examinations were performed, and fundus photographs and electroretinograms were obtained for selected patients. Blood samples were obtained from all patients and an additional seven family members who were not given examinations. Visual acuity in four affected individuals ranged from 20/40 to 20/80+. Patients described the onset of night blindness and colour vision defects in the second decade of life, with the earliest at 13 years of age. Examined affected individuals had constricted visual fields and retinal findings compatible with RP. Based on full field electroretinography, cone function was more severely reduced than rod function. Female carriers had no ocular signs or symptoms and slightly reduced cone electroretinographic responses. Affected and non-affected family members were genotyped for 20 polymorphic markers on the X-chromosome spaced at 10 cM intervals. Genotyping data were analysed using GeneMapper software. Genotyping and linkage analyses identified significant linkage to markers DXS8061, DXS1073, and DXS1108 with two point LOD scores of 2.06, 2.17, and 2.20, respectively. Haplotype analysis revealed segregation of the disease phenotype with markers at Xq28.

Anti-Clq antibodies in patients with chronic hepatitis C infection.

OBJECTIVE: Extrahepatic autoimmune features of HCV infection include autoantibody production and the development of mixed cryoglobulinemia. Anti-Clq antibody, detected with high frequency in systemic lupus erythematosus and hypocomplementemic urticarial vasculitis, may have a direct pathogenic role in complement mediated autoimmune diseases. In this study, we investigate the prevalence of anti-Clq antibody in a population of patients with chronic HCV infection. METHODS: Serum was obtained from a group of 50 patients with chronic HCV infection and control groups comprised of patients with SLE, rheumatoid arthritis (RA), scleroderma (PSS), Sjögren's syndrome (SS), mixed connective tissue disease (MCTD), and healthy individuals. RESULTS: Anti-Clq antibody was detected in 38% of HCV patients compared with 2% of healthy controls (p < 0.0001). Levels were also significantly elevated in patients with SLE (61%), RA (20%), PSS (15%), SS (15%) and MCTD (15%). CONCLUSION: In addition to numerous other autoantibodies, patients with chronic HCV infection exhibit increased production of anti-Clq IgG antibodies. This observation may have implications for the pathogenesis of the mixed cryoglobulinemic vasculitis syndrome.

Angiotensin I-converting enzyme gene polymorphism is associated with myocardial infarction, but not with retinopathy or nephropathy, in NIDDM.

OBJECTIVE: To clarify the relationship between the angiotensin I-converting enzyme (ACE) gene polymorphism and diabetic micro- and macroangiopathy in patients with non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: We examined 267 NIDDM patients with various stages of diabetic retinopathy, 61 patients with myocardial infarction (MI), and 136 patients without MI. An insertion/deletion polymorphism of the ACE gene was typed by polymerase chain reaction. RESULTS: Although no association was found between ACE gene polymorphism and diabetic retinopathy or nephropathy, this polymorphism was associated with MI in the patients with NIDDM. Homozygotes for the deletion polymorphism (DD genotype) were found more frequently in diabetic patients with MI (31.1%) than in diabetic patients without ischemic heart disease (16.9%), with a relative risk of 2.22 (95% confidence interval 1.11-4.46, P = 0.024). CONCLUSION: These data indicate that ACE gene polymorphism is associated with MI, but not with retinopathy or nephropathy, in patients with NIDDM and suggest that the ACE gene confers susceptibility to diabetic macroangiopathy but not to microangiopathy.

Asp905Tyr polymorphism of the gene for the skeletal muscle-specific glycogen-targeting subunit of protein phosphatase 1 in NIDDM.

OBJECTIVE: To clarify the contribution of the Asp905Tyr polymorphism of the muscle-specific glycogen-targeting subunit of protein phosphatase 1 (PP1G) to insulin resistance and related diseases. RESEARCH DESIGN AND METHODS: We investigated the Asp905Tyr polymorphism of the PPP1R3 gene, which encodes the muscle-specific glycogen-targeting subunit of PP1G, in 259 Japanese patients with NIDDM and 194 healthy control subjects. RESULTS: No significant difference was found in the genotype distribution between NIDDM patients (N = 259; Asp/Asp = 0.10, Asp/Tyr = 0.44, Tyr/Try = 0.46) and healthy control subjects (n = 194; Asp/Asp = 0.13, Asp/Tyr = 0.37, Tyr/Tyr = 0.50) or between patient groups subdivided by the mode of treatment: NIDDM patients with insulin therapy (Asp/Asp = 0.14, Asp/Tyr = 0.46, Tyr/Tyr = 0.40) and those without insulin therapy (Asp/Asp = 0.07, Asp/Tyr = 0.43, Tyr/Tyr = 0.50). However, NIDDM patients with the Tyr allele, which was previously reported to be associated with insulin resistance, tended to have lower BMIs than those without this allele (Asp/Asp: 24.5 +/- 1.1 kg/m2, Asp/Tyr: 22.6 +/- 0.4 kg/m2, Tyr/Tyr: 22.8 + 0.3 kg/m2, P = 0.06 by analysis of variance). CONCLUSIONS: These data suggest that the Asp905Tyr polymorphism of the PPP1R3 gene is not associated with NIDDM or high BMI, both of which are known to be insulin-resistant states, in the Japanese population.

Asp905Tyr polymorphism of protein phosphatase 1 G subunit gene in hypertension.

A possible pathogenic polymorphism in the gene for the G subunit of the glycogen-associated regulatory form of protein phosphatase 1 (PP1 G subunit), causing an Asp-to-Tyr substitution at codon 905 (Asp905Tyr), has been reported to be associated with insulin resistance and hypersecretion of insulin in the white population. Since marked heterogeneity has been reported in the association of mutations of candidate genes with essential hypertension between Japanese and other ethnic groups, we investigated the association of Asp905Tyr with essential hypertension in Japanese subjects. The frequency of the Tyr allele in Japanese control subjects (0.70) was much higher than that in the Danish population (0.10, P<1x10(-8)), indicating that the Tyr allele, previously reported as a rare variant in white subjects, is a common allele in our population. The genotype distribution in Japanese hypertensive patients (n=109; Asp/Asp=0.09, Asp/Tyr=0.39, Tyr/Tyr=0.52) was not significantly different (chi2=0.7, df=2, P>.6) from that in normotensive control subjects (n=148; Asp/Asp=0.12, Asp/Tyr=0.36, Tyr/Tyr=0.52). Among subjects with different PP1 G subunit genotypes, there was no difference in blood pressure, serum cholesterol, plasma glucose and insulin levels, and glucose disposal rate estimated by the euglycemic hyperinsulinemic clamp test. These data indicate that the Asp905Tyr polymorphism of the PP1 G subunit is not associated with essential hypertension, nor with insulin resistance and/or hyperinsulinemia in Japanese patients with essential hypertension, suggesting that the polymorphism plays little if any role in susceptibility to insulin resistance or hypertension.

Purification and immunocharacterization of human brain glutamine synthetase and its detection in cerebrospinal fluid and serum by a sandwich enzyme immunoassay.

A modified procedure employing a single chromatographic step to purify glutamine synthetase from human brain is described. The enzyme was characterized by native, denaturing, and two-dimensional gel electrophoresis and immunoblotting. Yield and purity were assessed by enzyme activity assay and a newly developed sandwich enzyme immunoassay using a mouse monoclonal antibody against native sheep brain glutamine synthetase. The immunoassay detected glutamine synthetase protein in samples where the enzyme had been inactivated by repeated cycles of freezing and thawing, and in serum and cerebrospinal fluid where glutamine synthetase was undetectable by the enzyme activity assay. Native glutamine synthetase from human brain occurred as an octamer with an estimated molecular weight of 360-400 kDa. Under reducing and denaturing conditions, the enzyme dissociated into monomeric subunits with an estimated molecular weight of 44 kDa. The monomers were recognized by the monoclonal antibody on immunoblots but not in the sandwich enzyme immunoassay, suggesting that the antigenic site occurs once on each subunit. Both human and sheep brain glutamine synthetases were composed of three and four different types of subunits with isoelectric points ranging from 7.0-7.2 and 6.8-7.0, respectively.

Hepatocyte nuclear factor-1alpha gene and non-insulin-dependent diabetes mellitus in the Japanese population.

Recently, hepatocyte nuclear factor-1alpha(HNF-1alpha, which is encoded by the TCF1 gene) mutations were reported in a subset of patients with maturity onset diabetes of the young (MODY3). We studied the contribution of TCF1 to genetic susceptibility to common non-insulin-dependent diabetes mellitus (type 2) in Japanese subjects by investigating allelic association with type 2 diabetes use of three markers. We also studied the frequency of the G191D mutation, the only mutation of TCF1 reported so far in late-onset type 2 diabetes. A total of 356 subjects were studied. There were no significant differences in allele frequency of the three markers between patients with type 2 diabetes and control subjects. A G191D mutation was not found in the subjects studied, giving a frequency of less than 0.4% in common type 2 diabetes. The lack of association of type 2 diabetes with three markers in and near TCF1 suggests that mutations in TCF1 derived from a limited number of founders are not a major cause of common type 2 diabetes even in the genetically homogeneous Japanese population. The data also indicate that the G191D mutation in TCF1 plays little, if any, role in susceptibility to common type 2 diabetes in the Japanese.

Brillouin scattering study of salol: exploring the effects of rotation-translation coupling.

Brillouin scattering in liquids composed of optically and mechanically anisotropic molecules is affected by coupling between rotational and translational dynamics. While this effect has been extensively studied in depolarized (VH) scattering where it produces the "Rytov dip," recent theoretical analyses by Pick, Franosch show that it should also produce observable effects in polarized (VV) scattering [Eur. Phys. J. B 31, 217 (2003)]; 31, 229 (2003)]]. To test this theory, we carried out Brillouin scattering studies of the molecular glassformer salol in the temperature range 210-380 K, including VH-backscattering, VH-90 degrees, and VV-90 degrees spectra. The data were analyzed consistently to determine the effects of rotation-translation coupling on both the polarized and depolarized spectra. A previously unanticipated feature predicted by these authors was observed: a narrow negative region in the q -dependent part of the 90 degrees VV spectra, which we designate as the "VV dip." It is an analog of the Rytov dip observed at high temperatures in the 90 degrees VH spectra, which is also accurately described by this theory. Analysis of the 90 degrees VV spectra was carried out both with and without inclusion of translation-rotation coupling in order to determine quantitatively the role this coupling plays.

The prediction of coronary atherosclerosis employing artificial neural networks.

BACKGROUND: Atherosclerosis is a complex histopathologic process that is analogous to chronic inflammatory conditions. Several factors have been shown to correlate with the extent of atherosclerosis. Whereas hypertension, obesity, hyperlipidemia, diabetes, smoking, and family history are all well documented, recent literature points to additional associated factors. Thus, antibodies to oxidized low-density lipoprotein (oxLDL), cytomegalovirus (CMV), Chlamydia pneumonia, Helicobacter pylori, as well as homocysteine and C-reactive protein (CRP) levels have all been implicated as independent markers of accelerated atherosclerosis. HYPOTHESIS: In the current study we attempted to formulate a system by which to predict the extent of coronary atherosclerosis as assessed by angiographic vessel occlusion. METHODS: The 81 patients were categorized as having single-, double-, triple-, or no vessel involvement. The clinical data concerning the "classic" risk factors were obtained from clinical records, and sera were drawn from the patients for determination of the various parameters that are thought to be associated with atherosclerosis. RESULTS: Using four artificial neural networks, we have found the most effective parameters predictive of coronary vessel involvement were (in decreasing order of importance) antibodies to oxLDL, to cardiolipin, to CMV, to Chlamydia pneumonia, and to beta 2-glycoprotein I (beta 2GPI). Although important in the prediction of vessel occlusion, hyperlipidemia, hypertension, CRP levels, and diabetes were less accurate. CONCLUSION: The results of the current study, if reproduced in a larger population, may establish an integrated system based on the creation of artificial neural networks by which to predict the extent of atherosclerosis in a given subject fairly and noninvasively.

Four SNPS on chromosome 9p21 confer risk to premature, familial CAD and MI in an American Caucasian population (GeneQuest).

Genome-wide association studies have separately identified four single nucleotide polymorphisms (SNPs) on chromosome 9p21 that confer susceptibility to coronary artery disease (CAD) and myocardial infarction (MI). This study presents the first analysis of these SNPs (rs10757274, rs2383206, rs2383207, and rs10757278) in a premature, familial CAD/MI population (GeneQuest). We performed a case-control analysis of the GeneQuest Caucasian population with 310 cases with premature CAD and MI (average age at onset of 40.3 +/- 5.1) and 560 non-CAD controls to determine if these SNPs are associated with risk of CAD using both the population-based and family-based association study designs. The four SNPs are significantly associated with premature and familial MI and CAD in the GeneQuest Caucasian population (allelic P= 6.61 x 10(-7) to 1.87 x 10(-8)). Sib-TDT analysis showed that three of the four SNPs could confer significant susceptibility to premature CAD and MI. These results indicate that the four SNPs on chromosome 9p21 are also associated with premature, familial CAD.

Flow cytometric assessment of anti-neuronal antibodies in central nervous system involvement of systemic lupus erythematosus and other autoimmune diseases.

The objective of this study is to evaluate the association between anti-neuronal antibody (anti-NA) and central nervous system (CNS) manifestations of systemic lupus erythematosus (SLE) and other rheumatic diseases using a flow cytometric method. Anti-NA was measured by flow cytometry in serum and cerebrospinal fluid (CSF) samples from patients with SLE (n=44 for serum, n=17 for CSF), other rheumatic diseases (n=64 for serum, n=21 for CSF) and from healthy controls (n=65 for serum, n=18 for CSF). Serum anti-NA was more frequently observed in SLE (31.8%, 14/44) than in other rheumatic diseases (4.7%, 3/64, P<0.001) or in healthy controls (0%, 0/65, P<0.00001). In SLE patients, the frequency of serum anti-NA was significantly higher in CNS-SLE (76.5%, 13/17) than in non CNS-SLE (3.7%, 1/27, P<0.000001). CSF anti-NA was detected in 88.2% (15/17) of CNS-SLE and was more frequently detected in CNS-SLE (15/17, 88.2%) than in other rheumatic diseases with CNS involvement (1/21, 4.8%, P<0.000001) or in healthy controls (0/18, P<0.000001). In conclusion, serum anti-NA was more frequently found in CNS-SLE than in non CNS-SLE, other rheumatic diseases or in healthy controls. The frequency of CSF anti-NA in CNS-SLE was significantly higher than in other rheumatic diseases with CNS involvement or in healthy controls.

[Report of 4 cases for treating optic nerve inflammation through total ethmoidectomy under nasal endoscope].

OBJECTIVE: The curative effect of treating optic nerve inflammation through total ethmoidectomy under nasal endoscope is evaluated. METHOD: The operations through total ethmoidectomy under nasal endoscope for 4 patients who had optic nerve inflammation has been done. RESULT: Two patients have apparent effect while the other two patients are effective, and the symptoms such as snuffle, eye distension and headache are well remitted. CONCLUSION: Towards the sufferer who had both optic nerve inflammation and intercurrent nasosinusitis, when conservative treatment was invalid or the patient was relapsed after surgery, it is necessary to do the operation in season and its effective rate is satisfactory. Total ethmoidectomy under nasal endoscope is safety and reliable.

Synthesis of SnSe in various alkaline media under mild conditions.

The synthesis of SnSe was systematically investigated in various alkaline media and at various temperatures with SnCl2.2H2O and selenium as source materials. The basicity of the alkaline media and the reaction temperature are two key factors considered in our process. The synthesis of SnSe in sodium hydroxide solution and aqueous ammonia is limited to a narrow temperature range, while the synthesis in hydrazine hydrate and ethylenediamine proceeds over a wider range. The final products were characterized by X-ray diffraction pattern (XRD), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM). TEM results showed a variation of crystal morphology of SnSe obtained in different media. Two simple chemical mechanisms for the formation of SnSe are presented.

The association of antinuclear antibodies with organ involvement and survival in systemic sclerosis.

OBJECTIVES: To study the frequency and specificity of antinuclear antibodies (ANA) and their association with internal organ involvement and survival in systemic sclerosis (SSc). METHODS: Sera from 276 SSc patients were analysed by an indirect immunofluorescence (IIF) technique with HEp-2 cells as a substrate to categorize centromeric (ACA), nucleolar, speckled and homogeneous nuclear IIF patterns. Specific ANA were determined as follows: anti-DNA topoisomerase I (anti-topo I) by double immunodiffusion, anti-U1 RNP by passive haemagglutination, anti-RNA polymerase I, II and III (anti-RNAP) and anti-histone (AHA) antibodies by enzyme immunoassays. During the follow-up of 7.0+/-4.5 (mean+/-S.D.) yr the occurrence of clinical manifestations and internal organ involvement was registered. RESULTS: ANA were present in 84% of the patients. The most common patterns of the IIF were speckled (41%), homogeneous (25%), nucleolar (24%) and centromeric (18%). A nucleolar pattern was associated with pulmonary fibrosis (P < 0.01) and cardiomegaly (P < 0.05). ACA were related to organic vasculopathy (P < 0.05) and renal involvement (P < 0.01), but not to pulmonary fibrosis (P < 0.01). Anti-topo I were present in 9.4%, anti-U1 RNP in 21%, anti-RNAP in 22% and AHA in 16% of the patients. Pulmonary involvement was more common in patients with anti-topo I (P < 0.05), whereas AHA-positive patients were characterized by cardiac (P < 0.05), pulmonary (P < 0.05) and renal (P < 0.05) involvement. A nucleolar IIF pattern and AHA were both associated with a decreased survival [relative risk of death 1.71 (P < 0.05) and 2.36 (P < 0.01), respectively]. CONCLUSIONS: AHA and a nucleolar HEp-2 cell pattern may indicate critical organ involvement and predict a reduced survival in SSc patients.

Silicate antibodies in women with silicone breast implants: development of an assay for detection of humoral immunity.

Silicon, in the form of sodium silicate (Na2SiO3), adsorbed onto bovine serum albumin (BSA)-precoated plates served as the solid-phase antigen in an enzyme immunoassay to detect silicate-reactive antibodies in the plasma of 40 symptomatic women with silicone breast implants, 91 asymptomatic women with silicone breast implants, 50 healthy control women, and 52 women with rheumatic diseases and without silicone breast implants, Silicate-reactive antibodies of immunoglobulin G (IgG) or IgM isotypes were detected in the plasma of 30% (12 of 40) of the symptomatic women with silicone breast implants; 9% (8 of 91) of the asymptomatic women with silicone breast implants; 5% (1 of 20) of the women without implants who had systemic lupus erythematosus; and 0% (0 of 32) of the women without implants who had either Sjögren syndrome, scleroderma, or rheumatoid arthritis. Only 2% (1 of 50) of the sera from the healthy control women contained silicate-reactive antibodies. Preincubation of sera with silicate and eight other metal compounds (including SiO2) demonstrated that the IgG and IgM antibodies bound specifically to silicate, because preincubation with Na2SiO3 inhibited more than 90% of the activity, whereas CrO3, Li2SO4, MgSO4, NiSO4, HgCl2, ZrOCl2, BeSO4, and SiO2 failed to inhibit the IgG or IgM antibody binding to the silicate-BSA plates. Furthermore, the F(ab')2 portion and not the Fc portion of the silicate-reactive IgG was reactive with BSA-bound silicate in the enzyme immunoassay. The assay for silicate-reactive antibodies was quantified by assigning arbitrary units to a standard curve composed of serial twofold dilutions of high-positive (ten times higher than the cutoff) silicate antibody sera. This novel assay is a useful method for detecting and quantifying humoral immune response to silicate.