A revised estimate of twin concordance in systemic lupus erythematosus

OBJECTIVE

Based on a small clinical series and previously published case reports, concordance for systemic lupus erythematosus (SLE) among monozygous (MZ) twins has been reported to be as high as 69%. Using a larger and less biased sample, we provide another estimate of this percentage.

METHODS

We established a registry of twins with SLE, based upon self-reports and information provided by the patients' physicians. We used DNA fingerprinting to validate the reported zygosity in a sample of these twins.

RESULTS

Of 107 twin pairs meeting the American College of Rheumatology 1982 revised criteria for the diagnosis of SLE, 24% of 45 MZ pairs and 2% of 62 dizygous (DZ) pairs were concordant. The frequency distributions of diagnostic criteria and disease symptoms in the SLE patients were similar to those in other published reports of SLE patients. Zygosity was confirmed by DNA fingerprinting in a subsample of 15 self-described MZ twins and 7 self-described DZ twins. All individuals had correctly predicted their zygosity.

CONCLUSION

MZ concordance for SLE is similar to that for other autoimmune diseases and is much lower than previously believed.

Genetic diversity within Cryptosporidium parvum and related Cryptosporidium species

To assess the genetic diversity in Cryptosporidium parvum, we have sequenced the small subunit (SSU) rRNA gene of seven Cryptosporidium spp., various isolates of C. parvum from eight hosts, and a Cryptosporidium isolate from a desert monitor. Phylogenetic analysis of the SSU rRNA sequences confirmed the multispecies nature of the genus Cryptosporidium, with at least four distinct species (C. parvum, C. baileyi, C. muris, and C. serpentis). Other species previously defined by biologic characteristics, including C. wrairi, C. meleagridis, and C. felis, and the desert monitor isolate, clustered together or within C. parvum. Extensive genetic diversities were present among C. parvum isolates from humans, calves, pigs, dogs, mice, ferrets, marsupials, and a monkey. In general, specific genotypes were associated with specific host species. A PCR-restriction fragment length polymorphism technique previously developed by us could differentiate most Cryptosporidium spp. and C. parvum genotypes, but sequence analysis of the PCR product was needed to differentiate C. wrairi and C. meleagridis from some of the C. parvum genotypes. These results indicate a need for revision in the taxonomy and assessment of the zoonotic potential of some animal C. parvum isolates.

Neuropsychiatric syndromes in lupus: prevalence using standardized definitions

OBJECTIVE

The San Antonio Lupus Study of Neuropsychiatric Disease is a longitudinal study designed to characterize the spectrum of and important risk factors for specific neuropsychiatric systemic lupus erythematosus (NPSLE) syndromes.

METHODS

Subjects must meet criteria for SLE and must be at least 18 years of age. A standardized medical history, neurologic, rheumatologic, and psychiatric examinations, computerized neuropsychological evaluation, and serologic testing are performed.

RESULTS

This report is based on the first 128 subjects (120 women and 8 men) who completed the initial study visit. Data from this initial study visit were evaluated for the prevalence of NPSLE using the American College of Rheumatology case definitions for 19 NPSLE syndromes. One or more NPSLE syndromes were present in 80% of subjects: cerebrovascular disease (2, 2%; ischemic stroke); headaches (73, 57%); mononeuropathy (9, 8%; median 8, ulnar 1); movement disorder (1, 1%; chorea); neuropathy, cranial (2, 2%; trigeminal); polyneuropathy (29, 22%; sensorimotor); seizures (21, 16%; partial); anxiety disorder (27, 24%); major depressive-like episode (37, 28%); mood disorder with depressive features (21, 19%); mood disorder with manic features (3, 3%); mood disorder with mixed features (1, 1%); psychosis (6, 5%). In a subset of 67 patients who received standardized neuropsychological testing, 21% had normal results. In the remainder, the following levels of impairment were seen: 43% mild, 30% moderate, and 6% severe.

CONCLUSIONS

The prevalence of NPSLE was high in this cohort of unselected patients with SLE. Headaches, cognitive dysfunction, and psychiatric disorders were the most common NPSLE syndromes seen. These results will be easily comparable to other studies also using standardized diagnostic criteria. However, the lack of ethnicity and language-matched normative neuropsychological data may make comparisons of cognitive dysfunction in SLE populations difficult.

High incidence of cardiovascular events in a rheumatoid arthritis cohort not explained by traditional cardiac risk factors

OBJECTIVE

To compare the incidence of cardiovascular (CV) events in persons with rheumatoid arthritis (RA) with that in people from the general population, adjusting for traditional CV risk factors.

METHODS

Two hundred thirty-six consecutive patients with RA were assessed for the 1-year occurrence of 1) CV-related hospitalizations, including myocardial infarction, stroke or other arterial occlusive events, or arterial revascularization procedures, or 2) CV deaths. Both outcomes were ascertained by medical records or death certificates. For comparison, we used CV events that occurred during an 8-year period among participants in an epidemiologic study of atherosclerosis and CV disease who were ages 25-65 years at study entry. We calculated the age- and sex-stratified incidence rate ratio (IRR) of CV events between the 2 cohorts and used Poisson regression to adjust for age, sex, smoking status, diabetes mellitus, hypercholesterolemia, systolic blood pressure, and body mass index.

RESULTS

Of the 236 RA patients, 234 were observed for 252 patient-years, during which 15 CV events occurred. Of these, 7 incident events occurred during the 204 patient-years contributed by patients ages 25-65 years, for an incidence of 3.43 per 100 patient-years. In the comparison cohort, 4,635 community-dwelling persons were followed up for 33,881 person-years, during which 200 new events occurred, for an incidence of 0.59 per 100 person-years. The age- and sex-adjusted IRR of incident CV events associated with RA was 3.96 (95% confidence interval [95% CI] 1.86-8.43). After adjusting for CV risk factors using Poisson regression, the IRR decreased slightly, to 3.17 (95% CI 1.33-6.36).

CONCLUSION

The increased incidence of CV events in RA patients is independent of traditional CV risk factors. This suggests that additional mechanisms are responsible for CV disease in RA. Physicians who provide care to individuals with RA should be aware of their increased risk of CV events and implement appropriate diagnostic and therapeutic measures.

Dagenais GR, Gerstein HC, Holman R, Budaj A, Escalante A, Hedner T, Keltai M, Lonn E, McFarlane S, McQueen M, Teo K, Sheridan P, Bosch J, Pogue J, Yusuf S. Effects of ramipril and rosiglitazone on cardiovascular and renal outcomes in people with impaired glucose tolerance or impaired fasting glucose: results of the Diabetes REduction Assessment with ramipril and rosiglitazone Medication (DREAM) trial

OBJECTIVE

Impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) are risk factors for diabetes, cardiovascular disease (CVD), and kidney disease. We determined the effects of ramipril and rosiglitazone on combined and individual CVD and renal outcomes in people with IGT and/or IFG in the Diabetes REduction Assessment With ramipril and rosiglitazone Medication (DREAM) trial.

RESEARCH DESIGN AND METHODS

A total of 5,269 people aged >or=30 years, with IGT and/or IFG without known CVD or renal insufficiency, were randomized to 15 mg/day ramipril versus placebo and 8 mg/day rosiglitazone versus placebo. A composite cardiorenal outcome and its CVD and renal components were assessed during the 3-year follow-up.

RESULTS

Compared with placebo, neither ramipril (15.7% [412 of 2,623] vs. 16.0% [424 of 2,646]; hazard ratio [HR] 0.98 [95% CI 0.84-1.13]; P = 0.75) nor rosiglitazone (15.0% [394 of 2,635] vs. 16.8% [442 of 2,634]; 0.87 [0.75-1.01]; P = 0.07) reduced the risk of the cardiorenal composite outcome. Ramipril had no impact on the CVD and renal components. Rosiglitazone increased heart failure (0.53 vs. 0.08%; HR 7.04 [95% CI 1.60-31.0]; P = 0.01) but reduced the risk of the renal component (0.80 [0.68-0.93]; P = 0.005); prevention of diabetes was independently associated with prevention of the renal component (P < 0.001).

CONCLUSIONS

Ramipril did not alter the cardiorenal outcome or its components. Rosiglitazone, which reduced diabetes, also reduced the development of renal disease but not the cardiorenal outcome and increased the risk of heart failure.

How much disability in rheumatoid arthritis is explained by rheumatoid arthritis?

OBJECTIVE

To measure the proportion of disability explained by disease manifestations compared with nondisease factors in rheumatoid arthritis (RA).

METHODS

A hypothetical model of the disablement process specific for RA was constructed using the demographic, sociocultural, and clinical characteristics of a consecutive cohort of RA patients. Disability was measured with the modified Health Assessment Questionnaire (M-HAQ) and the physical function scale of the Medical Outcomes Study Short Form 36 (SF-36) questionnaire. Independent variables, grouped according to their position in the RA disablement process model, were sequentially entered in a series of hierarchical regression models. The proportion of variance in disability explained by each group of variables was measured by the group's incremental R2.

RESULTS

The overall proportion of disability explained by the full model was 59%. Factors in the main disease-disability pathway explained 33%, of which 3% was explained by disease duration, 5% by the Westergren erythrocyte sedimentation rate, 14% by articular signs and symptoms, and 11% by performance-based functional limitations. External modifiers and contextual variables explained 26% of the variance in disability, of which age and sex accounted for 2%, formal education 4%, psychological status 17%, and symptoms of depression 3%.

CONCLUSION

Both the main disease-disability pathway and factors external to this pathway contribute significantly to disability in RA. These findings provide evidence of the relative influence of psychosocial factors, compared with disease manifestations, on the disability of patients with RA.

Neurological manifestations of antiphospholipid antibody syndrome

Thrombosis, thrombocytopenia, recurrent fetal loss and a variety of non-thrombotic neurological disorders have all been associated with antiphospholipid antibodies (aPL). Cerebral ischemia associated with aPL is the most common arterial thrombotic manifestation. Depression, cognitive dysfunction, depression and psychosis have all been associated with aPL. The presumed pathophysiologic mechanism underlying these manifestations is thought to be a result of cerebral ischemia in some, but not all cases. Seizures, chorea and transverse myelitis all appear to be associated with aPL. An interaction between aPL and central nervous system cellular elements rather than aPL-associated thrombosis seems to be a more plausible mechanism for these clinical manifestations. Migraine on the other hand, does not appear to be associated with aPL in either lupus or non-lupus populations. Neuroimaging studies show an increased frequency of brain abnormalities in patients with aPL, but none appear to be specific. The best treatment strategy for preventing neurological manifestations of aPL is not fully defined. For thrombotic manifestations, both antiplatelet and anticoagulant therapies have been suggested. In some patients, immunosuppressant therapy has been used. For non-thrombotic manifestations, some combination of immunosuppressant therapy and symptomatic treatment may be warranted.

Recipients of hip replacement for arthritis are less likely to be Hispanic, independent of access to health care and socioeconomic status

OBJECTIVE

To compare the proportion of Hispanics among recipients of hip replacements for primary articular disorders, recipients of knee replacements for the same reason, and persons hospitalized for other reasons.

METHODS

Twelve of the 17 accredited hospitals in Bexar County, Texas, in which hip or knee replacement surgery is performed permitted us to review their medical records. From 1993 through 1995, 3,100 elective, non-fracture-related, hip or knee replacements were performed. These individuals were matched by age, sex, hospital, and month of admission with 4,604 persons hospitalized for other reasons. Age, sex, ethnic background, type of medical insurance, median household income by zip code of residence, joint replaced, and surgical diagnosis were abstracted from the medical records. The validity of variables abstracted from the medical records was tested by comparison with self-report data in 115 patients interviewed prior to elective hip or knee replacement surgery.

RESULTS

During the study period, 2,275 subjects had a total knee replacement and 825 had a total hip replacement. Recipients of hip replacements were significantly less likely to be Hispanic than were recipients of knee replacements (19.5% versus 29.9%; odds ratio [OR] 0.57, 95% confidence interval [95% CI] 0.46-0.71; P < or = 0.001) or persons hospitalized for other reasons (29.4% Hispanic; OR 0.67, 95% CI 0.55-0.81). The under-representation of Hispanics was more pronounced among persons undergoing hip replacement for osteoarthritis compared with recipients of knee replacements for the same disease (OR 0.48, 95% CI 0.37-0.62). This pattern persisted after adjusting for age, sex, type of medical insurance, and median household income by the zip code of residence. Concordance between medical records and self-report data on ethnic background was high (kappa = 0.93).

CONCLUSION

Recipients of hip replacement are less likely to be Hispanic than are other hospitalized persons with a similar level of access to care. The reasons for this under-representation probably involve factors in addition to lack of access to health care and low socioeconomic status. Further research is needed to understand the nature of such factors.

Accuracy of anticardiolipin antibodies in identifying a history of thrombosis among patients with systemic lupus erythematosus

OBJECTIVE

To measure the accuracy of anticardiolipin antibodies (aCL) in identifying a history of thrombosis among patients with systemic lupus erythematosus (SLE) or the primary antiphospholipid syndrome (PAPS).

PATIENTS AND METHODS

Patients with SLE or PAPS who attended our rheumatology clinic between April 1992 and March 1994 were included in a retrospective analysis of the relationship between thrombotic events and aCL. All aCL measurements were performed in the same laboratory by enzyme-linked immunosorbent assay, blinded as to the presence or absence of thrombosis. The diagnostic accuracy of IgG, IgM, and IgA aCL was quantified by means of the receiver operating characteristic area under the curve (ROC AUC) for each isotype. Stratum-specific likelihood ratios and their 95% confidence intervals were calculated to define strata with optimal discriminant power.

RESULTS

During the period of study, aCL was measured in 117 patients (113 SLE and 4 PAPS), of whom 24 (20.5%) had experienced thrombotic events. The ROC AUC +/- the standard error for IgG aCL was 0.81 +/- 0.05, signifying an 81% accuracy in the identification of a history of thrombosis. In contrast, the accuracy of the IgM and IgA aCL was significantly lower (0.60 +/- 0.08 and 0.54 +/- 0.07, respectively, P < 0.05). Using stratum-specific likelihood ratios, we defined three strata in the IgG aCL scale that discriminate between patients with low, indeterminate, and high probabilities of thrombosis. For IgG aCL levels below 21.4 IgG phospholipid (GPL) U/mL, the posttest probability of thrombosis was 0.07, whereas for IgG aCL levels > or = 65.1 GPL U/mL, the posttest probability of thrombosis was 0.75. For IgG aCL values between 21.4 and 65.0 GPL U/mL, the probability of thrombosis was 0.20, equivalent to the entire cohort.

CONCLUSIONS

The IgG aCL determinations perform well in the identification of thrombosis in SLE or PAPS, while the IgM and IgA aCL have poor diagnostic accuracy. These findings may have implications for management of these patients.

Lactic acid bacterial diversity in the traditional mexican fermented dough pozol as determined by 16S rDNA sequence analysis

The lactic acid bacteria diversity of pozol, a Mexican fermented maize dough, was studied using a total DNA extraction and purification procedure and PCR amplification of 16S rDNA for gram-positive and related bacterial groups. Thirty-six clones were obtained and sequenced to 650 nucleotides. These partial sequences were identified by submission to the non-redundant nucleotide database of NCBI. The identified sequences were aligned with reference sequences of the closest related organisms. This analysis indicated that only 14 sequences were unique clones and these were identified as Lactococcus lactis, Streptococcus suis, Lactobacillus plantarum, Lact. casei, Lact. alimentarium, and Lact. delbruekii and Clostridium sp. Two non-ribosomal sequences were also detected. Unlike other environments analyzed with this molecular approach where many unidentified microorganisms are found, the identity of most sequences could be established as lactic acid bacteria, indicating that this is the main group among the gram-positive bacteria in pozol. Use of this molecular method permitted detection of lactic acid bacteria different from those previously isolated and identified by culture techniques

Inhibitory action of various 5-HT1B receptor agonists on rat masculine sexual behaviour

The systemic administration of the 5-HT1B receptor agonists, RU 24969 (0.25 and 0.5 mg/kg), TFMPP (0.25 and 0.5 mg/kg) and mCPP (0.75 and 1.0 mg/kg) resulted in an inhibition of rat masculine sexual behaviour reflected as a reduction in the proportion of copulating animals. Additionally, the analysis of the sexual behaviour of the animals obtaining ejaculation revealed that RU 24969 and TFMPP administration resulted in an increase in the number of mounts and in a prolongation of the intromission and ejaculation latencies and of the postejaculatory interval. Administration of mCPP increased the number of mounts preceding ejaculation. None of these changes could be attributed to a motor coordination impairment since none of these drugs, at the doses tested, produced changes in a treadmill test. The administration of the 5-HT1A agonist, ipsapirone (2.5, 5 and 10 mg/kg) resulted in a facilitation of the sexual behaviour expressed as a reduction in the number of intromissions preceding ejaculation accompanied by a shortening of the ejaculation latency. Present data show a differential action of 5-HT1A and 5-HT1B receptor subtypes in the control of rat masculine sexual behaviour. The hypothesis that the endogenous serotonin inhibitory action on copulation is mediated via the 5-HT1B receptor subtype is proposed.

HLA-DRB1 alleles associated with susceptibility or resistance to rheumatoid arthritis, articular deformities, and disability in Mexican Americans

OBJECTIVE

To study the genetics (HLA-DRB1 allele associations) of rheumatoid arthritis (RA) susceptibility and severity among Mexican Americans, an important, but understudied, US population.

METHODS

HLA-DRB1 alleles were compared between 141 Mexican American patients with RA and 54 unrelated Mexican Americans without RA, and the association of these alleles with articular deformities and disability was examined. HLA-DRB1 alleles were typed using polymerase chain reaction-sequence-specific primer amplification and were classified according to the 1996 World Health Organization nomenclature.

RESULTS

Of the 141 patients, 105 (74%) had at least 1 copy of the shared epitope (SE) sequence, compared with 29 (54%) of the 54 controls (P = 0.007). A significant gene-dose effect was observed, with 31 patients (22%) being homozygous for the SE compared with 1 (2%) of the controls (P = 0.004). In terms of disease severity, only 3% of RA patients who were "null" for the SE were outliers in the rate of development of articular deformities, compared with 10% of heterozygotes and 27% of homozygotes (P = 0.002). Patients who were DRB1*08 positive had significantly fewer deformities per year of disease and a slower rate of development of disability than did patients with other DRB1 alleles.

CONCLUSION

HLA-DRB1 alleles containing the SE are associated with susceptibility to RA in Mexican Americans, and may also be associated with a more rapid development of articular deformities and disability. HLA-DRB1*08 appears to have a protective influence on RA susceptibility and disease severity in Mexican Americans.

Molecular genetics of speciation and human origins

The major histocompatibility complex (MHC) plays a cardinal role in the defense of vertebrates against parasites and other pathogens. In some genes there are extensive and ancient polymorphisms that have passed from ancestral to descendant species and are shared among contemporary species. The polymorphism at the DRB1 locus, represented by 58 known alleles in humans, has existed for at least 30 million years and is shared by humans, apes, and other primates. The coalescence theory of populations genetics leads to the conclusion that the DRB1 polymorphism requires that the population ancestral to modern humans has maintained a mean effective size of 100,000 individuals over the 30-million-year persistence of this polymorphism. We explore the possibility of occasional population bottlenecks and conclude that the ancestral population could not have at any time consisted of fewer than several thousand individuals. The MHC polymorphisms exclude the theory claiming, on the basis of mitochondrial DNA polymorphisms, that a constriction down to one or few women occurred in Africa, at the transition from archaic to anatomically modern humans, some 200,000 years ago. The data are consistent with, but do not provide specific support for, the claim that human populations throughout the World were at that time replaced by populations migrating from Africa. The MHC and other molecular polymorphisms are consistent with a "multiregional" theory of Pleistocene human evolution that proposes regional continuity of human populations since the time of migrations of Homo erectus to the present, with distinctive regional selective pressures and occasional migrations between populations.

Symptoms of depression and psychological distress among hispanics with rheumatoid arthritis

OBJECTIVE

To explore the roles played by Hispanic ethnic background and acculturation to the mainstream English language culture of the United States in the depressive symptoms and mental health of rheumatoid arthritis (RA) patients.

METHODS

Members of a consecutive cohort of patients with RA were studied cross-sectionally. All underwent a comprehensive clinical and psychosocial evaluation. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression Scale (CES-D), and psychological distress was measured with the Medical Outcomes Study Short Form 36 (SF-36) mental health scale.

RESULTS

Two hundred thirty-six patients were studied. Women had significantly higher median CES-D scores than men (19 versus 14, P = 0.0004), Hispanics scored higher than non-Hispanics (14 versus 8, P = 0.0002), and foreign-born scored higher than US-born patients (14 versus 10, P = 0.009). Compared with those who were fully acculturated, patients who were partially acculturated were more likely to have a score > or = 16 on the RA-adjusted CES-D (odds ratio [OR] = 1.79, 95% confidence interval [95% CI] 1.37 to 2.35, P < or = 0.001). Among unacculturated patients, the likelihood of a score > or = 16 increased 6-fold (OR = 6.68; 95% CI 3.50 to 12.72; P < or = 0.001). A similar, inverse pattern was observed for the SF-36 mental health scale. In multivariate models accounting for age, sex, education, income, articular pain, deformity, and the level of disability, low acculturation was independently associated with high depressive symptoms, and a Hispanic background was independently associated with lower SF-36 mental health.

CONCLUSIONS

In this consecutive series of RA patients, Hispanics, particularly those who are not fully acculturated to the mainstream Anglo society, had more depressive symptoms and psychological distress than did non-Hispanics.

Disaggregating pain and its effect on physical functional limitations

BACKGROUND

Pain is a common impairment that limits the abilities of older persons. The purposes of this article are to: (i) describe the distribution of pain location using the McGill Pain Map (MPM) in a community-based cohort of aged subjects; (ii) investigate whether individual areas of pain could be sensibly grouped into regions of pain; (iii) determine whether intensity, frequency, and location constitute independent dimensions of pain; and (iv) determine whether these three pain dimensions make differential contributions to the presence of self-reported physical functional limitations.

METHODS

A total of 833 Mexican American and European American subjects, aged 65-79 years, were enrolled in the San Antonio Longitudinal Study of Aging and were interviewed in their homes between 1992 and 1996. A total of 373 (46%) of the subjects reported having pain in the past week. Physical functional limitations were ascertained using the nine items from the Nagi scale. Three composite scales were created: upper extremity, lower extremity, and total. Pain intensity and frequency were ascertained using the McGill Pain Questionnaire. Pain location was ascertained by using the MPM.

RESULTS

Pain was reported in every area of the MPM. Using multiple groups confirmatory factor analysis, the 36 areas were grouped into 7 regions of pain: head, arms, hands and wrists, trunk, back, upper leg, and lower leg. Among persons with pain, pain frequency, intensity, and location were weakly associated with each other. Pain regions were primarily independent of each other, yet weak associations existed between 6 of the 21 pair-wise correlations between regions. Pain regions were differentially associated with individual physical functional limitations. Pain in the upper leg was associated with 8 of the 9 physical tasks. In multivariate analyses, age, gender, and ethnic group accounted for only 2-3% of the variance in physical tasks. In multivariate analyses, age, gender, and ethnic group accounted for only 2-3% of the variance in physical functional limitations. Pain intensity accounted for 5-6% of the variance in the composite scores of functional limitation. Pain frequency accounted for 4-5% of the variance in upper extremity limitations but did not contribute to the modeling of lower extremity limitations. In contrast, pain location accounted for 9-14% of the variance in physical functional limitations.

CONCLUSIONS

We tested a method for ascertaining pain location and clearly demonstrated that pain location is an important determinant of self-reported physical functional limitations. The MPM methodology may be used in population-based studies or in clinical samples that focus on specific impairments and seek to control for pain frequency and intensity. Future studies can link specific diseases with the common impairment of pain and tease out the pathways that lead to other impairments (e.g., weakness), functional limitations, and disability.

Prevalence of point mutations in the dihydrofolate reductase and dihydropteroate synthetase genes of Plasmodium falciparum isolates from India and Thailand: a molecular epidemiologic study

Pyrimethamine-sulfadoxine (PS) is used as a second-line treatment for P. falciparum malaria patients who fail to respond to chloroquine. Resistance to these drugs has been shown to encode with point mutations in dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) genes. Our aim was to assess the comparative rate of point mutation occurring in DHFR and DHPS genes among P. falciparum isolates from India and Thailand where the use of PS is at a different rate. We used the mutation-specific polymerase chain reaction (PCR) technique and mutation-specific restriction digestion to determine the prevalence of DHFR and DHPS gene mutations at codons 16, 51, 59, 108, 164 and at 436, 437, 581 and 613, respectively. In the 89 clinical isolates from India, in the case of the DHFR gene, we found 71 of S108N, 10 of N51I, 28 of C59R and four of I164L types. Among the 50 isolates from Thailand the rate of point mutations in the DHFR gene was higher at four codon positions. We found 47 of S108N, 18 of N51I, 23 of C59R and 12 of I164L types. None of the isolates from either country possessed the paired mutations S108T and A16V. Mutations of the DHPS gene were less frequent among the Indian isolates: 4.5% showed DHPS gene mutation, two of S436F, A437G, A613T and two of S436F, A613T; whereas 66% (33/50) of the Thai isolates had mutated at codons 436, 437, 581 and 613 which include 13 of S436F, 15 of A437G, 19 of A581G and 25 of A613S/T, ranging from single to quadruple mutant types. Among the Indian isolates, DHFR point mutations were very frequent and 85/89 had a wild type DHPS genetic profile. The pattern of mutations in the samples from Thailand was different, as most were associated with point mutations in DHFR and DHPS genes.

Lower limb arterial incompressibility and obstruction in rheumatoid arthritis

BACKGROUND

Despite increased cardiovascular morbidity and mortality in rheumatoid arthritis, the peripheral arteries remain understudied.

OBJECTIVE

To examine the lower limb arteries in age and sex matched, non-smoking subjects with and without rheumatoid arthritis.

METHODS

The ankle-brachial index (ABI) was measured at the posterior tibial and dorsal pedal arteries. Arteries were classified as obstructed with ABI < or =0.9, normal with ABI >0.9 but < or =1.3, and incompressible with ABI >1.3. Multinomial logistic regression was used to estimate differences in ABI between patients and controls, adjusting for cardiovascular risk factors, rheumatoid arthritis manifestations, inflammation markers, and glucocorticoid dose.

RESULTS

234 patients with rheumatoid arthritis and 102 controls were studied. Among the rheumatoid patients, 66 of 931 arteries (7%) were incompressible and 30 (3%) were obstructed. Among the controls, three of 408 arteries (0.7%) were incompressible (p = 0.002) and four (1%) were obstructed (p = 0.06). At the person level, one or more abnormal arteries occurred among 45 rheumatoid patients (19%), v five controls (5%, p = 0.001). The greater frequency of arterial incompressibility and obstruction in rheumatoid arthritis was independent of age, sex, and cardiovascular risk factors. Adjustment for inflammation markers, joint damage, rheumatoid factor, and glucocorticoid use reduced rheumatoid arthritis v control differences. Most arterial impairments occurred in rheumatoid patients with 20 or more deformed joints. This subgroup had more incompressible (15%, p< or =0.001) and obstructed arteries (6%, p = 0.005) than the controls, independent of covariates.

CONCLUSIONS

Peripheral arterial incompressibility and obstruction are increased in rheumatoid arthritis. Their propensity for patients with advanced joint damage suggests shared pathogenic mechanisms.

Prognostic indicators of chronic chagasic cardiopathy

After 104 patients with positive serology for Chagas' disease had been followed for a decade, a selection of 66 patients was made from this number and a total of 25 variables obtained from clinical and paraclinical findings were analyzed, with the purpose of knowing which of these variables may be of help, in time, in determining prognosis. The information was analyzed using the Cox regression model. The patients were classified into groups according to the results in the invasive and noninvasive studies: those with a normal electrocardiogram without heart disease (14 patients) or with early segmental abnormalities of the left ventricle (9 patients); those with an abnormal electrocardiogram and advanced myocardial damage but without signs of congestive heart failure (26 patients); and those with an abnormal electrocardiogram together with congestive heart failure (17 patients). Of these patients, those with electrocardiographic abnormalities correspond to stages of the disease where advanced myocardial damage is proven. There was a 42% mortality during the follow-up of these patients. According to the regression model, the value of the systolic blood pressure is a good predictor of mortality (P = 0.0380) in those with congestive heart failure. When we analyzed jointly the patients with an abnormal electrocardiogram, we found that several variables (systolic blood pressure, the presence of atrial fibrillation, the radiologic cardiothoracic index, and left ventricular end-diastolic volume obtained by the ventriculogram), were negatively correlated with regard to survival. This last model has a chi-square of 11.36 (P = 0.0228). These models allow us to predict the prognosis in this group of patients with Chagas' disease and advanced myocardial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of presynaptic serotonergic receptors on the mechanism of action of 5-HT1A and 5-HT1B agonists on masculine sexual behaviour: physiological and pharmacological implications

In order to establish whether the 5-HT1A or the 5HT1B agonists, 8-OH-DPAT or TFMPP, produce their facilitatory or inhibitory actions on masculine sexual behaviour via a mechanism involving: (a) the serotonin synthesis or release; (b) the stimulation of presynaptic receptors, or (c) the stimulation of somatodendritic receptors, three series of experiments were performed. The administration of the serotonin synthesis inhibitor, p-chlorophenylalanine (p-CPA, 300 mg/kg x 3 days), facilitated sexual behaviour but does not interfere neither with the inhibitory nor with the facilitatory effects of TFMPP (0.5 mg/kg) or 8-OH-DPAT (0.5 mg/kg), respectively. The icv or the intraraphé administration of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), slightly stimulated masculine sexual behaviour and produced a decrease in serotonin and its metabolite levels. In lesioned animals TFMPP (0.5 mg/kg) resulted in an inhibitory effect reflected as a prolongation of the ejaculation latency. The inhibitory effect of this drug on mounting behaviour was not observed in 5,7-DHT treated rats. In lesioned animals 8-OH-DPAT (0.5 mg/kg) produced the same facilitatory effect. Present data indicate that serotonergic postsynaptic receptors mediate both the inhibitory and the facilitatory actions of TFMPP or 8-OH-DPAT in copulation. All data further support the idea that endogenous serotonin acts via the stimulation of 5-HT1B receptors to induce its inhibitory effects on masculine sexual behaviour.

Validating a computerized neuropsychological test battery for mixed ethnic lupus patients

Patients with systemic lupus erythematosus (SLE) often show cognitive impairment on traditional neuropsychological tests; however, many of these tests are unsuitable for use with mixed ethnic populations. Computer-administered cognitive tests are promising, but have not been validated against traditional tests or with predominantly Hispanic samples. We gave 67 lupus patients a computer-administered test battery (Automated Neuropsychological Assessment Metrics--ANAM) and a battery of traditional neuropsychological tests. The two batteries were compared using correlation and multiple regression analyses. All patients were fluent in English, 54% were Hispanic and 13% were bilingual. Non-Hispanic patients were predominantly European American (37%). About 80% of patients were rated as impaired on traditional tests. Hispanics were younger, had less education and more current SLE disease activity than non-Hispanics; but did not differ in lifetime SLE-related organ damage or current steroid use. Hispanics and younger patients were more impaired on many of the traditional tests, while ANAM was not affected by Hispanic ethnicity or education. ANAM tests were moderately correlated with analogous traditional tests. Age and selected ANAM scores accounted for about 60% of the variance in the traditional battery. These results replicate the high prevalence of cognitive deficits in SLE found by others and suggest that computer-administered tests like ANAM may be useful for assessment of cognitive impairment in mixed-ethnic samples. Confounding variables such as age, education, English language fluency and prior experience with tests were identified and need to be controlled statistically or with comparison groups in future studies.

Enzymes involved in carbohydrate metabolism and their role on exopolysaccharide production in Streptococcus thermophilus

The role of the enzymes uridine-5'-diphospho-(UDP) glucose pyrophosphorylase and UDP galactose 4-epimerase in exopolysaccharide production of Gal- ropy and non-ropy strains of Streptococcus thermophilus in a batch culture was investigated. Growth of the ropy and non-ropy strains was accompanied by total release of the galactose moiety from lactose hydrolysis in modified Bellinker broth with lactose as the only carbon source. This was associated with a greater exopolysaccharide production by the ropy strain. The polymer produced by both strains in cultures with lactose or glucose as carbon sources contained glucose, galactose and rhamnose, indicating that glucose was used as a carbon source for bacterial growth and for exopolysaccharide formation. UDP-glucose pyrophosphorylase activity was associated with polysaccharide production during the first 12 h in a 20 h culture in the ropy strain, but not in the non-ropy strain. UDP-galactose 4-epimerase was not associated with exopolysaccharide synthesis in any strain. The evidence presented suggests that the glucose moiety from lactose hydrolysis is the source of sugar for heteropolysaccharide synthesis, due to a high UDP-glucose pyrophosphorylase activity.

Determinants of hip and knee flexion range: results from the San Antonio Longitudinal Study of Aging

OBJECTIVE

We analyzed data from the San Antonio Longitudinal Study of Aging, a neighborhood-based study of community-dwelling elderly people, to identify factors that determine the flexion range (FR) of hips and knees.

METHODS

The FR of hips and knees was measured in a cohort of 687 subjects aged 65 to 79 years. We used multivariate models to examine the associations among the FR of hips and knees, and between these and age, gender, ethnicity, body mass index (BMI), pain and its location, self-reported arthritis, and diabetes mellitus. The functional relevance of hip and knee FR was tested by measuring its association with 50-foot walking velocity.

RESULTS

More than 90 degrees of flexion in both hips and both knees was observed in 619 subjects (90.1%). Correlations among the FR of hips and knees ranged from 0.54 to 0.80 (P < 0.001 for Spearman r values). Multivariate analysis revealed a pattern of significant associations between each of the joints and its contralateral mate and ipsilateral partner joints that was consistent for both hips and both knees. Using each individual joint as the unit of analysis, the following variables were independently associated with hip or knee FR in multivariate models: rising BMI and female sex with reduced FR of both hips and knees, a Mexican American ethnic background with decreased hip FR, and knee pain with decreased knee FR. The functional importance of the FR of these two important joints was supported by its significant association with walking velocity in a model that adjusted for age, gender, ethnic background, BMI, and hip or knee pain.

CONCLUSIONS

Most community-dwelling elderly people have a FR of hips and knees that can be considered functional. The ipsilateral and contralateral hip or knee are significant independent determinants of the FR of each of these joints. Obesity, a health problem potentially amenable to preventive and therapeutic interventions, is a factor significantly associated with decreased FR of hips and knees.

Cardiac compression in rheumatoid pericarditis

Rheumatoid pericarditis occurs in approximately one third of rheumatoid arthritis (RA) patients. However, clinically apparent rheumatoid pericarditis is infrequent. The authors found clinical pericarditis in 12 of 960 patients admitted for RA, 5 of whom had manifestations of cardiac compression. These 5 had longer duration of RA, worse functional class, and more extraarticular features than the patients without cardiac compression. Presenting features of cardiac compression included dyspnea, edema, chest pain, and pulsus paradoxus. Treatment of patients with cardiac compression due to rheumatoid pericarditis may include a trial of systemically administered corticosteroids, but this should not delay surgical intervention for impending tamponade. Pericardiocentesis should only be performed as an emergency, life-saving procedure. It may be followed by intrapericardiac injection of corticosteroids, but this does not prevent recurrence. Longer-lasting benefit is obtained by surgical decompression. Two-year mortality in patients with cardiac compression was 100%. The literature on the subject is reviewed.

What do self-administered joint counts tell us about patients with rheumatoid arthritis?

OBJECTIVE

This report presents data from two sources showing that a self-administered joint count (SAJC) suitable for use in clinical settings provides information comparable with that of observer-assessed joint counts.

METHODS

Patients were tested with a 1-page form containing a 40-joint mannequin on which they could mark their painful or swollen joints. The first sample of 110 patients was used to compare the SAJC with the tender or swollen joint counts (TJC or SJC) performed by a rheumatologist and to a battery of clinical and laboratory measurements. The second sample consisted of 240 rheumatoid arthritis (RA) patients enrolled in a cohort study of RA outcomes, in whom the relationship between the SAJC and health-related quality of life measures was examined.

RESULTS

Test-retest reliability of the SAJC was excellent (ri = 0.89), as was its agreement with the observer-assessed TJC (ri = 0.78). The SAJC was significantly correlated (P < or = 0.01) to pain on a 10-point scale (r = 0.33), the McGill Pain Questionnaire (r = 0.27), the pain subscale of the Arthritis Impact Measurement Scales (AIMS) (r = 0.32), the duration of morning stiffness (r = 0.27), and to the AIMS subscales of physical function (r = 0.20), impact (r = 0.31), and global health (r = 0.29). The SAJC was inversely related to formal education (r = -0.32), but did not correlate significantly with the modified Health Assessment Questionnaire, walking velocity, grip strength, or erythrocyte sedimentation rate. The responsiveness of the SAJC was comparable with that of other measures commonly employed to assess RA outcomes. Either the SAJC or the TJC could be included alternatively in multivariate models to explain 7 of the 8 subscales of the Medical Outcomes Study Short Form-36 (SF-36) questionnaire.

CONCLUSION

The SAJC is a reliable and responsive measure that agrees highly with the observer-assessed TJC and is significantly associated to the health-related quality of life of patients with RA. Given its low cost and ease of administration, it is suggested that SAJC be included in future studies of RA outcome in routine clinical practice.

Epidemiology and impact of rheumatic disorders in the United States Hispanic population

The emergence of a sizable Hispanic population in the US is a relatively recent historical phenomenon, and thus much is still unknown about this group of North Americans. Data from national surveys suggest small differences between Hispanic and non-Hispanic white populations in the age-adjusted prevalence of self-reported arthritic conditions. However, the rate of activity-limitation attributable to arthritis is higher among Hispanic patients. This likely reflects the poorer socioeconomic conditions and lack of health insurance that prevail among Hispanic populations, which may limit their access to rheumatologic care. Osteoporotic vertebral and hip fractures are less frequent, and proximal femoral mineral density is higher, in Hispanic individuals than in non-Hispanic white individuals. The mechanisms for these observations are currently under investigation. There have been no studies of the prevalence of osteoarthritis, rheumatoid arthritis, or systemic lupus erythematosus among Hispanic populations. However, important immunogenetic, clinical, and psychosocial differences between Hispanic and non-Hispanic patients in regard to rheumatoid arthritis and systemic lupus erythematosus have been reported. There is no published information on the prevalence or characteristics of other rheumatic diseases in the US Hispanic population. Emerging evidence suggests considerable underuse of certain health services for arthritis among Hispanic patients, likely due in part to socioeconomic factors. Further research is needed to determine whether biologic, cultural or psychosocial factors contribute to underuse as well. There is clearly a need for data on the prevalence and characteristics of arthritis and other rheumatic and musculoskeletal diseases in this emerging US population.