Mental State Inferences Abilities Contribution to Verbal Irony Comprehension in Older Adults with Mild Cognitive Impairment.

OBJECTIVE: The present study examined mentalizing capacities as well as the relative implication of mentalizing in the comprehension of ironic and sincere assertions among 30 older adults with mild cognitive impairment (MCI) and 30 healthy control (HC) subjects. METHOD: Subjects were administered a task evaluating mentalizing by means of short stories. A verbal irony comprehension task, in which participants had to identify ironic or sincere statements within short stories, was also administered; the design of the task allowed uniform implication of mentalizing across the conditions. RESULTS: Findings indicated that participants with MCI have second-order mentalizing difficulties compared to HC subjects. Moreover, MCI participants were impaired compared to the HC group in identifying ironic or sincere stories, both requiring mental inference capacities. CONCLUSION: This study suggests that, in individuals with MCI, difficulties in the comprehension of ironic and sincere assertions are closely related to second-order mentalizing deficits. These findings support previous data suggesting a strong relationship between irony comprehension and mentalizing.

Cysteinyl-leukotrienes induce vascular endothelial growth factor production in human monocytes and bronchial smooth muscle cells.

BACKGROUND: Cysteinyl leukotrienes (cysLTs) are suggested to be implicated in the process of airway remodelling in asthma. OBJECTIVE: We investigated the potential for cysLTs to modulate vascular endothelial growth factor (VEGF) expression, a growth factor involved in the angiogenesis of airway remodelling. METHODS: VEGF mRNA and protein were quantified by real-time PCR and ELISA, respectively. VEGF promoter activation was assessed using luciferase gene-tagged promoter constructs. RESULTS: We found that LTD(4) induction of VEGF in human monocytes and bronchial smooth muscle cells is cysLT1 dependent. Stimulation of HEK293 cells stably expressing cysLT1 or cysLT2 with cysLTs showed a concentration-dependent activation of the VEGF promoter and a time-dependent increase in VEGF mRNA and protein. For the cysLT1-mediated response, mutations of hypoxia-induced factor-1 (HIF-1) sites failed to reduce cysLT-induced VEGF promoter activation and 5' deletions showed that the proximal region containing one AP-1 and four specificity protein 1 (Sp1) sites was necessary. Pretreatment with inhibitors of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), but not p38, and an overexpression of dominant negative forms of c-Jun, c-Fos or Ras suggested the implication of mitogen-activated protein kinases and AP-1. Mutation of the AP-1-binding element failed to prevent VEGF transactivation suggesting that AP-1 might not act directly on the promoter. Moreover, inhibition of Sp1-dependent transcription by mithramycin completely inhibited VEGF promoter transactivation and VEGF mRNA expression by LTD(4) . Finally, mutations of Sp1 binding elements prevented VEGF promoter transactivation. CONCLUSION AND CLINICAL RELEVANCE: Our data indicate for the first time that cysLTs can transcriptionally activate VEGF production via cysLT1 receptors, with the involvement of JNK, ERK, the AP-1 complex and Sp1. These findings suggest that cysLTs may be important in the angiogenic process of airway remodelling and potentially provide a previously unknown benefit of using cysLT1 receptor antagonists in the prevention or treatment of airway remodelling in asthma.

Clinical diagnoses in young offspring from eastern Québec multigenerational families densely affected by schizophrenia or bipolar disorder.

OBJECTIVE: The follow-up since 1989 of a large sample of multigenerational families of eastern Québec that are densely affected by schizophrenia (SZ) or bipolar disorder (BP) has permitted to look at the rates of DSM diagnoses in the young offspring of a SZ parent (HRSZ) and of a BP parent (HRBP) who had an extremely loaded family history. METHOD: The sample (average age of 17.5, SD 4.5) consisted of 54 high-risk offspring (HR) having one parent affected by a DSM-IV SZ or BP. The parents descended from 21 multigenerational families that constitute a quasi-total sample of such kindred in eastern Québec. The HRs were administered a lifetime best estimate DSM-IV diagnosis. RESULTS: We observed that the rates, the diversity of diagnoses, the high comorbidity, the severity and the age of onset of the clinical diagnoses tended to be similar with those already reported in the offspring of affected parents with a low familial loading. Although the sample size was small, HRSZ and HRBP also tended to show similarities in their clinical status. CONCLUSION: Overall, taking into account methodological limitations, the observation early in life of some shared characteristics among HRSZ and HRBP in terms of non-psychotic diagnosis may be congruent with the accumulating evidence that several phenotypic features are shared in adulthood by the two major psychoses.

Effects of novel manufacturing technology on blood and dialysate flow distribution in a new low flux "alpha Polysulfone" hemodialyzer.

The main target for low flux hemodialyzers is an efficient low molecular weight solutes clearance. Such efficiency is largely dependent on the optimization of diffusion between blood and dialysis solution. The diffusion process can be impaired if there is a mismatch between blood and dialysate flow distribution in the dialyzer. Thus optimized flow distribution both in the blood and dialysate compartment becomes quintessential for the maximal efficiency of the diffusion process within the hemodialyzer. The present paper describes the distribution of the blood and dialysate flows in a new low flux polysulfone hollow fiber hemodialyzer characterized by a specific undulation of the fibers and a new cutting technology of the fibers for an improved micro-flow condition in the blood compartment headers. Twelve Diacap alpha Polysulfone LO PS 15 (1.5 sqm) (B. Braun Medizintechnologie, Melsungen Germany) were employed for the study. Six were analyzed in vitro and six were studied in vivo. Blood flow distribution was studied in vitro by dye injection in the blood compartment during experimental extracorporeal circulation utilizing human blood with hematocrit adjusted at 33%. Sequential images were obtained with a helical scanner in a fixed longitudinal section of the dialyzer 1 cm thick. Average and regional blood flow velocities were measured utilizing the reconstructed imaging sequence. The method allowed the calculation of single fiber blood flow (SF Qb) and the mass transfer zone (MTR) definition in digitally subtracted images. The patterns 20-10 and 40-30 were utilized. The same technology was used to evaluate flow distribution in the dialysate compartment after dye injection in the Hansen's connector. Regional dialysate flow was calculated in central and peripheral sample areas of 1 cm2. Six in vivo hemodialysis treatments on patients with end stage renal disease were performed at three different blood flow rates (250-350 and 450 ml/min) in order to measure urea, creatinine and phosphate clearance. Macroscopic and densitometrical analysis revealed that flow distribution was homogeneous in the blood compartment while in the dialysate compartment a slight difference between the peripheral and central regions in terms of flow velocity was observed. This however was not generating channeling phenomena. Urea creatinine and phosphate clearances were remarkably high and so were the Kt/V observed in all sessions, especially in relation to the studied blood flows. In conclusion, a significant blood to dialysate flow match with optimized countercurrent flow condition was observed in the studied hollow fiber hemodialyzers. Such optimization might be due both to the improved dialyzer design at the level of the blood header and to the specific fiber undulation that prevents dialysate channeling.

Enhancing the educational achievement of at-risk youth.

This study examined a non-school program aimed at enhancing the educational performance of economically disadvantaged early adolescents who live in public housing. The educational enhancement program included discussions with adults, writing activities, leisure reading, homework, helping others, and games using cognitive skills. A three-arm research design juxtaposed program youth who received educational enhancements with comparison youth in affiliated facilities who did not receive the program and with control youth in other community programs without educational enhancements. From youths, follow-up data collected 2 1/2 years after baseline revealed uniformly positive outcomes for program youth on measures of reading, verbal skills, writing, and tutoring. Teacher reports at final follow-up favored program and comparison youth over controls on measures of reading, writing, games, overall school performance, and interest in class material. School grades were higher for program youth than for comparison and control youth for reading, spelling, history, science, and social studies. Overall grade averages were higher for program youth versus comparisons and controls, as was school attendance. Study data lend empirical support to the provision of educational enhancements in non-school settings for at-risk youths.

Relationship between lipoprotein- and oxidation-related variables and atheroma lipid composition in subjects undergoing coronary artery bypass graft surgery.

The relationship between atheroma lipid composition and serum lipoprotein and oxidation measurements has not been fully explored. To address this question, we studied serum, plasma, and aortic wall specimens from 66 subjects undergoing coronary artery bypass graft surgery. The lipid composition of aortic specimens was characterized in terms of cholesterol ester and cholesterol crystal plus phospholipid by using hot-stage polarizing light microscopy; tissue oxidation status was assessed by measuring conjugated dienes. Serum lipoprotein-related measurements included total cholesterol, triglyceride, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, apolipoproteins B and AI, and lipoprotein(a). Oxidation status was assessed by measuring LDL mobility, thiobarbituric acid-reactive substances, LDL conjugated dienes, and IgG and IgM autoantibodies against oxidized LDL. Fasting blood glucose was also determined. Lesion cholesterol crystal plus phospholipid content was associated inversely with serum HDL cholesterol levels (r=-0.279, P=0.029) and positively with fasting blood glucose (r=0.359, P=0.016), LDL mobility (0.276, P<0.05), and IgM autoantibodies against oxidized LDL (r=0.272, P=0.037). There was also a significant relationship between the level of aortic tissue conjugated dienes and plasma LDL mobility (r=0.332, P=0.007). In multivariate analysis, IgM autoantibodies against oxidized LDL, fasting blood glucose, and LDL mobility, in descending order of significance, together accounted for 35% of the variability in aortic lesion cholesterol crystal plus phospholipid content. These data support direct and independent roles for oxidation and hyperglycemia in the pathophysiology of atherosclerosis.

Effect of low-density lipoprotein (LDL) antigen source on an enzyme-linked immunosorbent assay for autoantibodies against oxidized LDL.

We examined the effect of antigen source on an enzyme-linked immunosorbent assay (ELISA) for autoantibodies against oxidized low-density lipoprotein (LDL). Serum samples from 20 subjects with systemic lupus erythematosus (SLE) and from 20 controls were assayed for immunoglobulin G (IgG) and immunoglobulin M (IgM) autoantibodies against oxidized LDL, using either a pooled or individual (n = 3) LDL preparation as antigen. For IgG autoantibodies against oxidized LDL there was a relationship (r approximately 0.5, P < 0.01) between data obtained using individual versus pooled antigen preparations. Bias plots demonstrated consistent inverse, concentration-dependent relationships (r approximately -0.6, P < 0.001). The difference in IgG autoantibodies against oxidized LDL levels between SLE patients and controls was underestimated (39-58%) when assays used individual rather than pooled LDL antigen. For IgM autoantibodies against oxidized LDL the direct relationships were stronger (r approximately 0.8, P < 0.001) and the concentration-dependent relationships weaker (r approximately -0.3, significance variable) than for IgG autoantibodies against oxidized LDL. Variations between LDL preparations suggested that a pooled antigen would give a more stable assay. Thus, LDL antigen source is important in assays for both IgG and IgM autoantibodies against oxidized LDL.

Prospective study of Chlamydia pneumoniae IgG seropositivity and risks of future myocardial infarction.

BACKGROUND: Chlamydia pneumoniae has been hypothesized to play a role in atherothrombosis. However, prospective data relating exposure to Chlamydia pneumoniae and risks of future myocardial infarction (MI) are sparse. METHODS AND RESULTS: In a prospective cohort of nearly 15 000 healthy men, we measured IgG antibodies directed against Chlamydia pneumoniae in blood samples collected at baseline from 343 study participants who subsequently reported a first MI and from an equal number of age- and smoking-matched control subjects who did not report vascular disease during a 12-year follow-up period. The proportion of study subjects with IgG antibodies directed against Chlamydia increased with age and cigarette consumption. However, prevalence rates of Chlamydia IgG seropositivity were virtually identical at baseline among men who subsequently reported first MI compared with age- and smoking-matched control subjects. Specifically, the relative risks of future MI associated with Chlamydia pneumoniae IgG titers >/=1:16, 1:32, 1:64, 1:128, and 1:256 were 1.1, 1.0, 1.1, 1.0, and 0.8, respectively (all probability values not significant). There was no association in analyses adjusted for other risk factors, evaluating early as compared with late events, or among nonsmokers. Further, there was no association between seropositivity and concentration of C-reactive protein, a marker of inflammation that predicts MI risk in this cohort. CONCLUSIONS: In a large-scale study of socioeconomically homogeneous men that controlled for age, smoking, and other cardiovascular risk factors, we found no evidence of association between Chlamydia pneumoniae IgG seropositivity and risks of future MI.

Analytical evaluation of particle-enhanced immunonephelometric assays for C-reactive protein, serum amyloid A and mannose-binding protein in human serum.

Against a background of growing interest in more sensitive assays for quantifying various acute phase proteins, we evaluated the performance of recently developed tests for C-reactive protein (CRP), serum amyloid A (SAA) and mannose-binding protein (MBP) on the Behring nephelometer II (BNII). Sample results outside the calibration ranges of 3.5 to 220 mg/L for CRP, 3.3 to 215 mg/L for SAA and 0.09 to 5.6 mg/L for MBP were automatically re-measured at another dilution. The lower limits of detection were 0.01, 0.7 and 0.01 mg/L for CRP, SAA and MBP, respectively. The coefficients of variation (CV) for intra- (n > or = 20) and inter- (n > or = 15) assay precision were < 5.2% and < 8.5%, respectively, for the three proteins at concentrations representing low, normal and high. Linearity for each method was within 5% of the expected values throughout the calibration range. We observed no significant interference from bilirubin (up to 300 mg/L) or haemoglobin (up to 10 g/ L) for the three tests. Method comparison studies performed for CRP and SAA yielded the following results: y (CRP on BNII) = 0.75x (ELISA, Hemagen) -0.25 mg/L (r = 0.981, Sy/x = 2.1 mg/L; y (SAA on BNII) = 1.44x (ELISA, Hemagen) -9.9 mg/L (r = 0.972, Sy/x = 6.9 mg/L), where ELISA is enzyme-linked immunosorbent assay. Reference intervals established in 261 adult blood donors (aged 36.2 +/- 9.0 years) were found to be log-normal with 2.5th, 50th, and 97.5th centiles of < 0.17, 1.00 and 10.1 mg/L for CRP, < 0.84, 2.10 and 9.70 mg/L for SAA; and 0.30, 1.28 and 4.10 mg/L for MBP. We observed no relationship with CRP concentration and age; however, SAA levels increased with age while MBP levels decreased. The BNII provides a simple, rapid and sensitive system for measuring CRP, SAA and MBP in human serum.

The relationship between apolipoprotein E and serum oxidation-related variables is apolipoprotein E phenotype dependent.

To examine the relationship between apolipoprotein E and serum oxidation status, we assayed apolipoprotein E level, apolipoprotein E phenotype, and levels of lipid peroxides and transition metal ions and their binding proteins in sera from apparently healthy individuals. The study group included 129 women aged 22-63 years and 53 men aged 22-56 years. Among subjects with apolipoprotein E 4/3 phenotype, lipid peroxide levels were higher compared with E 3/2 phenotype (786 +/- 182 nmol/l vs. 659 +/- 174 nmol/l, P = 0.015), and ceruloplasmin levels were slightly higher compared with apolipoprotein E 3/3 phenotype (0.28 +/- 0.08 mg/l vs. 0.26 +/- 0.06 mg/l, P = 0.035). In the study group as a whole, there were significant associations between serum apolipoprotein E level, and serum levels of ceruloplasmin (r = 0.266, P < 0.001) and ferritin (r = 0.2, P < 0.007). Among subjects with apolipoprotein E 4/3 phenotype, there was a significant association between serum apolipoprotein E and lipid peroxide levels (r = 0.470, P < 0.01), which was not apparent among subjects with E 3/3 or E 3/2 phenotypes. In multivariate analysis, apolipoprotein E phenotype was a small but significant independent contributor to variation in serum lipid peroxide levels. These data suggest that there may be heterogeneity among apolipoprotein E phenotypes in their relationships with serum lipid oxidation status.

Effects of conditioned media on porcine embryos at different stages of development.

The objective of our study was to determine the effect of conditioning media with homologous porcine uterine cells on the developmental rate of porcine embryos. Cell monolayers were prepared by selective dissection and digestion of sections from the uterus of prepuberal gilts that were primed with PMSG and hCG. Conditioned media were used with 2 type of embryos: 4-cell stage (Experiment 1) or blastocyst stage (Experiment 2). In Experiment 1, embryos were collected surgically by flushing the oviducts, 36 to 48 h following the first of 2 inseminations. Embryos were cultured in Whitten's medium containing 1.5% BSA as a protein source until they attained the 4-cell stage. Embryos at the 4-cell stage were cultured randomly in either Whitten's medium with 1.5% BSA or Whitten's medium with 1.5% BSA that was previously conditioned for 24 h with an endometrial epithelial cell monolayer. Embryos were cultured in 50-microl drops covered with oil in a 38.5 degrees C, 5% CO(2) in air incubator. There was no advantage to using the conditioned media with the 4-cell stage embryos. The embryos were less developed than those cultured in nonconditioned Whitten's medium (P <0.001). In Experiment 2, embryos were cultured at the blastocyst stage. They were recovered the same way as in Experiment 1 and then cultured in Whitten's medium containing 1.5% BSA until they reached the blastocyst stage. At the blastocyst stage (Day 6), embryos were randomly assigned to 1 of the 6 following treatments: Whitten's with 1.5% BSA or Whitten's plus 1.5% BSA that was previously conditioned with endometrial epithelial cell monolayer, TCM-199 containing 0.4% BSA or TCM-199 plus 0.4% BSA that was previously conditioned with endometrial epithelial cell monolayer, finally, TCM-199 containing 10% serum or TCM-199 plus 10% serum that was previously conditioned with endometrial epithelial cell monolayer. Results show that initiation of hatching was significantly enhanced by conditioning the Whitten's media.

Ureaplasma urealyticum infection of the placenta in pregnancies that ended prematurely.

OBJECTIVE: To investigate the relationship between Ureaplasma urealyticum infection of the placenta and premature onset of labor. METHODS: We studied 647 pregnancies that resulted in the live birth of an infant weighing less than 1501 g. The chorionic surface of the placenta was cultured for U urealyticum, Mycoplasma hominis, and group B streptococci. RESULTS: The rate of ureaplasma isolation increased with increasing interval between rupture of membranes and delivery. When analyses were limited to the 96 singleton pregnancies that ended within 1 hour of rupture of membranes and before the 29th week of gestation, U urealyticum was prominently associated with an increased risk of premature onset of labor (P = .008 unadjusted, and P = .05 when adjustment was made for all potential confounders). Ureaplasma infection rate was lowest in pregnancies terminated because of severe maternal preeclampsia or progressive fetal growth restriction. CONCLUSION: Ureaplasma urealyticum infection is associated with premature onset of labor and with increasing duration of time between rupture of membranes and delivery. Eradication of ureaplasmas from the urogenital tract of women and their partners, ideally before conception, should be considered.

Anti-oxidized LDL antibodies and antiphospholipid antibodies in healthy subjects: relationship with lipoprotein- and oxidation-related analytes.

IgG autoantibodies against malondialdehyde-modified LDL (alpha oxLDL), antiphospholipid antibodies (APA) and oxidation- and lipoprotein-related analytes were assayed in sera from healthy subjects (51 males, 115 females, aged 22-63 years). alpha OxLDL levels were associated (P < 0.03) with IgG alpha cardiolipin (r = 0.18), IgM alpha cardiolipin (r = 0.17) and IgM alpha phosphatidyl-serine (r = 0.16) but not with age, cholesterol, triglyceride, apolipoproteins B and AI, lipoprotein(a), lipid peroxides, ceruloplasmin, copper, ferritin, transferrin or iron. APA levels were inversely associated with levels of both oxidation- and lipoprotein-related analytes. Ferritin (3.5%) and alpha oxLDL (1.4%) contributed independently to variation in IgG alpha cardiolipin levels, and apo B (2%) to variation in IgM alpha cardiolipin levels. These associations are small, indicating that there are no major biological associations between the measured variables. The lack of association between alpha oxLDL and lipoprotein- or oxidation-related analytes suggests that the relevant antigen is not in serum.

Oxidation-related analytes and lipid and lipoprotein concentrations in healthy subjects.

The relations between oxidation-related analytes and lipoprotein risk factors for coronary heart disease are poorly understood. To address this issue, ceruloplasmin, copper, iron, ferritin, cotinine, lipid peroxides, cholesterol, triglyceride, apoB, apoA-I, and lipoprotein(a) levels were measured in sera from apparently healthy subjects (51 men and 115 women). Pairwise comparisons revealed strong positive associations (P < .001) of copper and ceruloplasmin with lipid peroxides, total cholesterol, triglycerides and apoB, of transferrin with apoA-I and cholesterol, and of ferritin with triglycerides. Serum levels of oxidation-related analytes did not differ between smokers and nonsmokers. In multivariate analysis, serum copper was the major independent determinant of serum lipid peroxide level, accounting for 15% of the variability in concentration (ferritin accounted for 1.6%). Copper and ceruloplasmin accounted for 20.5% of the variation in triglyceride levels; triglycerides and apoB accounted for 12% of the variability in ferritin levels; apoB and apoA-I accounted for 9% of the variability in transferrin levels. The data suggest that serum copper contributes to lipid peroxidation in vivo. There are significant associations between lipoprotein and transition metal-related analytes, and further work is needed to elucidate the physiological basis for these relations.

Further characterization of the plasma lipoprotein(a) distribution.

The plasma lipoprotein (a) [Lp(a)] distribution in caucasians is heavily skewed to the right, with evidence of bimodality. As there is a well-described inverse relationship between apolipoprotein(a) [apo(a)] size and Lp(a) concentration, it is likely that the presence of multiple apo(a) isoforms of differing frequency has a significant impact on the final distribution of Lp(a) concentrations. We have previously described an immunoblot method for examining the relationship between apolipoprotein(a) [apo(a)] size and lipoprotein(a) [Lp(a)] mass among samples heterozygous for apo(a) size, thus eliminating confounding by null or undetected apo(a) isoforms. In the present study, this method has been applied to examine the plasma Lp(a) distribution, independent of the effects of apo(a) isoform size and frequency. Seventy subjects heterozygous for apo(a) size were studied. To take into account the inverse relationship (P < 0.001) between apo(a) isoform size and Lp(a) concentration, Lp(a) data associated with each apo(a) isoform were normalized as multiples of the median Lp(a) concentration for that isoform. These apo(a) isoform-independent Lp(a) data demonstrated a strikingly multimodal distribution, with five major peaks. The relative frequencies of Lp(a) peaks 1-5 were 17.1%, 15.0%, 35.7%, 23.6%, and 8.6%, and associated median Lp(a) concentrations were 1.0, 6.2, 15.0, 21.8, and 39.6 mg/dL, respectively. Multivariate analysis demonstrated that apo(a) isoform size accounted for 23% and isoform-independent Lp(a) peaks for 59.5% of the variation in Lp(a) concentration. Further investigation of the characteristics of the apo(a) isoform-independent Lp(a) distribution is warranted.

ELISA of IgG antibody to oxidized low-density lipoprotein: effects of blocking buffer and method of data expression.

We describe an ELISA for serum IgG antibodies against malondialdehyde-modified low-density lipoprotein (mLDL). Optimal antigen concentration, serum dilution, and dilution of enzyme-conjugated second antibody were 25 mg/L, 1:250, and 1:5000, respectively, when 5 g/L human serum albumin was used for blocking. When data were expressed as mLDL/LDL (the ratio of IgG binding to mLDL vs LDL), within-run and between-run CVs were 7.0% and 8.9%, respectively. Antibody concentrations expressed as mLDL/LDL or as mLDL-LDL (the difference between IgG binding to mLDL and to LDL) were higher in women with systemic lupus erythematosus (n = 20) than in controls (n = 20) (P < 0.001). With bovine serum albumin or Superblock blocking buffers, only the mLDL-LDL data were significant. Thus, the choice of blocking agent and the method of data expression should be carefully considered when assaying IgG antibodies against mLDL.

Antibiotic susceptibilities of AIDS-associated mycoplasmas.

Because mycoplasmas may be a cofactor in the progression of human immunodeficiency virus infection to AIDS, their susceptibilities to antibiotics need to be known in the event that appropriate therapy is required. The mycoplasmas studied were a stock culture strain of Mycoplasma fermentans, two strains of M. fermentans isolated from patients with AIDS, M. fermentans var. incognitus, Mycoplasma penetrans, and Mycoplasma pirum. The antibiotics tested were doxycycline, tetracycline, clindamycin, ofloxacin, erythromycin, azithromycin, and clarithromycin at levels consistent with the attainable levels in serum. By the macrodilution metabolic inhibition method, all six mycoplasma strains were susceptible to doxycycline, tetracycline, clindamycin, ofloxacin, azithromycin, and clarithromycin. M. penetrans was susceptible to erythromycin. The M. fermentans strains and M. pirum were resistant to erythromycin. The macrodilution metabolic inhibition method results showed agreement with the Sensititre Gram Positive MIC Panel results for tetracycline, clindamycin, and erythromycin. MICs of clarithromycin for all six mycoplasma isolates tested were low, indicating susceptibility.

Apolipoprotein (a): a comparison of isoforms identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or by sodium dodecyl sulfate-agarose gel electrophoresis.

Lipoprotein(a) resembles low density lipoprotein in structure, except that a unique apolipoprotein (apo), apo(a), is linked to apo B-100. Variations in the number of sequence repeats in the apo(a) gene give rise to a range of isoforms. Depending on the method used, 6-30 apo(a) isoforms have been observed; however, the correspondence of these different isoforms has not been reported, making between-study comparisons difficult. In the present study we address this question by characterizing the apo(a) phenotypes of 48 sera using two previously reported separation methods, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, 3-12% gels) and SDS-agarose gel electrophoresis. In addition, the molecular weight of each isoform was estimated using haptoglobin 2-2 polymers as molecular weight standards. Among the 48 sera, 15 distinct apo(a) isoforms were separated by SDS-PAGE and 28 by SDS-agarose gel electrophoresis. There was excellent correlation between the two nomenclature systems (r = -0.97, p < 0.001, by rank correlation), and the ranges were totally overlapping, with the same two isoforms being identified as the largest and smallest by either method. The apparent molecular mass range for the isoforms was 294-624 kDa, which is in close agreement with the theoretical molecular mass range of 238-643 kDa, calculated from the sequence and carbohydrate content of recombinant apo(a). The disparity in number of isoforms between methods was expected, due to the poorer separation of apo(a) by SDS-PAGE; 3.1 +/- 1.7 (median, 2.0) SDS-agarose isoforms were combined for each SDS-PAGE isoform.(ABSTRACT TRUNCATED AT 250 WORDS)