Sj-FABPc fatty-acid-binding protein of the human blood fluke Schistosoma japonicum: structural and functional characterization and unusual solvent exposure of a portal-proximal tryptophan residue

Sj-FABPc of the blood fluke of humans, Schistosoma japonicum, is a member of the FABP/P2/CRBP/CRABP family of beta-barrel cytosolic fatty-acid-binding and retinoid-binding proteins. Sj-FABPc has at least eight different variants encoded by a single-copy polymorphic gene. In fluorescence-based assays, recombinant Sj-FABPc was found to bind 11-(dansylamino)undecanoic acid (DAUDA), inducing a shift in peak fluorescence emission from 543 to 493 nm. A similar spectral change was observed in dansyl-amino-octanoic acid (in which the dansyl fluorophore is attached at the alpha-carbon rather than the omega-carbon of DAUDA), indicating that the ligand enters entirely into the binding site. Sj-FABPc also bound the naturally fluorescent cis-parinaric acid, as well as oleic acid and arachidonic acid, by competition, but not all-trans-retinol. Dissociation constants were, for cis-parinaric acid, K(d)=2.5+/-0.1 microM (mean+/-S.E.M.) and an apparent stoichiometry consistent with one binding site per molecule of Sj-FABPc and, for oleic acid, K(i) approximately 80 nM. A deletion mutant from which alpha-II was absent failed to bind ligand. Sj-FABPc modelled well to known structures of the protein family; an unusually solvent-exposed Trp side chain was evident adjacent to the presumptive portal through which ligand is thought to enter and leave. Intrinsic fluorescence analyses of Sj-FABPc and of the deletion mutant (from which Trp-27 is absent) confirmed the unusual disposition of this side chain. Virtually all members of the FABP/P2/CRBP/CRABP protein family have prominent hydrophobic side chains in this position, with the exception of liver FABP and ileal FABP, which instead have charged side chains. Liver FABP is known to be distinct from other members of the protein family in that it does not seem to contact membranes to collect and deposit its ligand. It is therefore postulated that the unusually positioned apolar side chains in Sj-FABPc and others in the family are important in interactions with membranes or other cellular components.

Characterisation and expression of a cDNA encoding the 80-kDa large subunit of Schistosoma japonicum calpain

We describe the cloning of a full length calpain-encoding cDNA constructed from two truncated cDNAs isolated from a cDNA library prepared with mRNA isolated from adult worms of the Philippine strain of Schistosoma japonicum. The cDNA sequence is 2.456 kb in length and predicts a protein of 758 residues with a molecular mass of 86.61 kDa and an isoelectric point of 5.34. Probes spanning the entire calpain cDNA hybridised to multiple bands in genomic DNAs of Philippine (SjP) and Chinese (SjC) S. japonicum, with some restriction fragment length polymorphisms evident between the two strains. Northern hybridisation analysis indicated that the cDNA codes for a single RNA transcript between 2.6 and 3.6 kb in size in the SjP and SjC genomes. After subcloning in the QIA express vectors pQE-31 and pQE-40 and subsequent expression, the recombinant protein was purified and shown to bind calcium. The availability of recombinant S. japonicum calpain will allow its future evaluation as a vaccine candidate, especially in light of recent work with the S. mansoni homologue which has provided evidence that this protein may be a target of protective immunity.

Risk of mortality following clinical fractures

To examine the risk of mortality following all clinical fractures, we followed 6459 women age 55-81 years participating in the Fracture Intervention Trial for an average of 3.8 years. All fractures and deaths were confirmed by medical record or death certificate. Clinical fractures were fractures that came to medical attention. Fracture status was used as a time-dependent covariate in proportional hazards models. The 907 women who experienced a fracture were older, had lower bone mineral density and were more likely to report a positive fracture history. A total of 122 women died over the course of the study with 23 of these deaths occurring after a clinical fracture. The age-adjusted relative risk (95% confidence intervals) of dying following a clinical fracture was 2.15 (1.36, 3.42). This primarily reflected the higher mortality following a hip fracture, 6.68 (3.08, 14.52); and clinical vertebral fracture, 8.64 (4.45, 16.74). Results were similar after adjusting for treatment assignment, health status and specific common comorbidities. There was no increase in mortality following a forearm or other fracture (non-hip, non-wrist, nonvertebral fracture). In conclusion, clinical vertebral fractures and hip fractures are associated with a substantial increase in mortality among a group of relatively healthy older women.

A low-cost approach to prospective identification of impending high cost outcomes

OBJECTIVES

The overall objective of this study was to define and evaluate patterns of use of medical services in the care of patients with chronic illness that represent circumstances which, if modified, might lead to reduction in risk of acute-level care.

METHODS

This was a retrospective observational study. The study population consisted of Kaiser Permanente enrollees at four sites during January 1993 through June 1995, who were 20 to 64 years of age and had two of three chronic diseases (diabetes, circulatory disorders, obstructive pulmonary disorders). Using logistic regression, the effect of primary care visit patterns and therapeutically risky drug combinations on likelihood of hospital admission in a subsequent 3-month period is adjusted for age, gender, and disease state in the prior 12-month period.

RESULTS

Enrollees with visits to three or more different primary care physicians were 46% more likely to be admitted than expected (P < 0.01) according to their age, gender, and disease state, and those with therapeutically risky drug combinations were 34% more likely to be admitted (P < 0.01).

CONCLUSIONS

The risk adjustment models evaluated in this study defined care processes associated with increased risk of subsequent acute-level services. Those processes may represent nascent acute disease states or suboptimal organization of care delivery. The results of these models can be used to inform changes in organization and delivery of outpatient care that might improve patient outcomes.

Osteoarthritis and risk of falls, rates of bone loss, and osteoporotic fractures. Study of Osteoporotic Fractures Research Group

OBJECTIVE

To examine the association between osteoarthritis (OA), as defined by radiographic evidence and self report, and osteoporotic fractures, falls, and bone loss in a cohort of elderly white women.

METHODS

A cohort of 5,552 elderly women from the Study of Osteoporotic Fractures was followed up prospectively for a mean of 7.4 years. Self-reported, physician-diagnosed OA was recorded at interview, and radiologic OA of the hip and hand were defined from pelvis and hand radiographs obtained at baseline by validated techniques. Prevalent and incident vertebral fractures were detected by vertebral morphometry, and data on incident fractures and falls were collected by postcard surveys; fractures were confirmed by radiography. Bone mineral density (BMD) was measured on 2 occasions at the hip, lumbar spine, and calcaneus, and rates of bone loss were calculated.

RESULTS

Women with radiographic hip OA had a reduced risk of recurrent falls in the first year (relative risk [RR] 0.7, 95% confidence interval [95% CI] 0.5-0.95). However, those with self-reported OA had an increased risk of falls (RR 1.4, 95% CI 1.2-1.5). Radiographic hip OA was associated with reduced bone loss in the femoral neck compared with controls (mean +/- SD -0.29+/-0.09%/year versus -0.51+/-0.03%/year; P = 0.018). However, radiographic hip OA showed nonsignificant trends toward increased bone loss at the calcaneus and lumbar spine. There was no significant association between self-reported OA or radiographic hand OA with bone loss. No definition of OA was associated with incident nonvertebral fracture, hip fracture, or vertebral fracture.

CONCLUSION

Despite having increased BMD compared with controls, subjects with OA did not have a significantly reduced risk of osteoporotic fracture, although there was a trend toward a reduced risk of femoral neck fractures in subjects with severe radiographic OA. The failure of the observed increase in BMD to translate into a reduced fracture risk may be due, in part, to the number and type of falls sustained by subjects with OA. Patients with OA should not be considered to be at a lower risk of fracture than the general population. Physicians should be aware that a high BMD in patients with OA may be falsely reassuring.

Serum vitamin D levels and incident changes of radiographic hip osteoarthritis: a longitudinal study. Study of Osteoporotic Fractures Research Group

OBJECTIVE

The purpose of this study was to determine the relationship of serum levels of 25-vitamin D and 1,25-vitamin D to incident changes of radiographic hip osteoarthritis (OA) among elderly white women.

METHODS

Baseline and followup hip radiographs of 237 subjects were obtained an average of 8 years apart. Hips were scored for individual radiographic features (IRF) and assigned a summary grade based on the number and type of IRF present. Serum 25- and 1,25-vitamin D levels from baseline samples were analyzed by radioimmunoassay. Logistic and linear regression were used to examine the association of 25- and 1,25-vitamin D levels with radiographic changes, adjusting for age, health status, physical activity, weight, vitamin D supplement use, and calcaneal bone mineral density.

RESULTS

The risk of incident hip OA defined as the development of definite joint space narrowing was increased for subjects who were in the middle (odds ratio [OR] 3.21, 95% confidence interval [95% CI] 1.06, 9.68) and lowest (OR 3.34, 95% CI 1.13, 9.86) tertiles for 25-vitamin D compared with subjects in the highest tertile. Vitamin D levels were not associated with incident hip OA defined as the development of definite osteophytes or new disease according to the summary grade. No association between serum 1,25-vitamin D and changes in radiographic hip OA was found.

CONCLUSION

Low serum levels of 25-vitamin D may be associated with incident changes of radiographic hip OA characterized by joint space narrowing.

Telemedicine in Micronesia

Distance and isolation profoundly affect the delivery of health care in the islands of Micronesia. The lack of specialty services on most of the islands has led to a costly off-island referral system that strains health care budgets. Care providers there have incorporated advances in telecommunications to create a telemedicine network amongst themselves and with a tertiary care hospital in Hawaii. They developed an interactive video conferencing system, a still-image transmission network, and a data transfer network for use principally in patient care and continuing education. Patients now receive earlier evaluation by off-island specialists as part of an effort to improve the appropriateness of off-island referrals. Regularly scheduled medical lectures are broadcast from Pohnpei, a main island, to physicians in several more remote locations. Transmission costs are kept low by using, when possible, preexisting public-service satellites, such as the PEACESAT system that serves the entire Pacific basin. The telemedicine system is evolving, and its success depends greatly on the cooperative relationships among the partners.

Recreational physical activity and the risk of osteoarthritis of the hip in elderly women

OBJECTIVE

The relationship between recreational physical activity and the risk of osteoarthritis (OA) of the hip in women is uncertain. We examined the cross sectional association of radiographic OA of the hip and past recreational and sports related physical activity in elderly women who are participants in the Study of Osteoporotic Fractures.

METHODS

An anteroposterior pelvic radiograph of 5818 subjects was assessed for hip OA using reliable measurements of individual radiographic features. Hips were graded on a summary scale of 0 (no findings) to 4 (severe OA) based on the number and type of radiographic features present. Logistic regression was used to examine the association of self-reported recreational physical activity (times/week) as a teenager, at age 30, and at age 50 with hip OA. All analyses were adjusted for age and body mass index at age 25 years.

RESULTS

The risk of moderate to severe radiographic hip OA in elderly women was modestly increased in elderly women who were in the highest quartile for all physical activities performed as a teenager (odds ratio 1.7, 95% confidence interval 1.1, 2.4), at age 50 (OR 1.4, 95% CI 1.0, 1.9) and weight bearing activities at age 30 (OR 1.4, 95% CI 1.0, 1.9) compared to women in the lowest quartile of activity. The risk of symptomatic hip OA (grade > or =2 hip OA + hip pain) was modestly increased in women who were in the highest quartile for all physical activities as a teenager (OR 2.0, 95% CI 1.2, 3.4), at age 50 (OR 1.6, 95% CI 1.0, 2.4), and weight bearing activities at age 30 (OR 1.6, 95% CI 1.0, 2.4) compared to women in the lowest quartile of activity.

CONCLUSION

Recreational physical activities performed by women before menopause may increase the risk of radiographic and symptomatic hip OA.

Molecular cloning and functional expression of a cDNA encoding the major endoplasmic reticulum-associated calcium-binding protein, calreticulin, from Philippine strain Schistosoma japonicum

We describe the cloning of a full length calreticulin (CR)-encoding cDNA clone isolated by immunoscreening of a cDNA library prepared with mRNA from adult worms of the Philippine strain of Schistosoma japonicum, the cause of Asian schistosomiasis. The sequence of the cDNA is presented, and its molecular characterisation and functional expression as a Ca2+-binding protein described. The potential role of CR in inducing protective immunity in the schistosomes is discussed.

Identification of novel 70-kDa heat shock protein-encoding cDNAs from Schistosoma japonicum

A diverse range of organisms respond to a variety of chemical, physiological and temperature-associated stresses by a rapid and transient increase in the synthesis of heat shock proteins. We immunoscreened a Uni-ZAP XR cDNA library, prepared from mRNA isolated from the Philippine strain of the Asian bloodfluke, Schistosoma japonicum, using hyperimmune rabbit sera raised against soluble adult S. japonicum proteins. Six 70-kDa heat shock protein-encoding cDNA clones were identified which, upon further analysis, were separated into two distinct protein groups within the 70-kDa heat shock protein family, the 70-kDa heat shock proteins and the immunoglobulin heavy chain-binding proteins/glucose-related proteins (Grp78). A representative from both groups was fully sequenced and compared with homologous sequences available in the GenBank/EMBL database as the first stage in determining the role of their expression products in the regulation of S. japonicum development, in the induction of immunity, and whether they act as molecular chaperones capable of modulating the correct folding or repair of proteins within this species of schistosome.

Characterization of the rat adrenal medulla cultured in vitro

A wide variety of experimental animal models have been used to investigate the mechanisms of synthesis, storage, and release of catecholamines. Whereas in vivo experimental models are situated at one end of the spectrum, cell culture models are situated at the other end. In the present study, we have characterized various aspects of the rat adrenal medulla cultured in vitro as a whole tissue, aiming to establish a new experimental model in between in vivo animal models and cell culture models. We adapted a bottle rotator system commonly used for culturing rodent whole embryos. Changes in histology, activities and mRNA levels of catecholamine-synthesizing enzymes, and concentrations of catecholamines in the adrenal medulla were studied. In addition, the effects of cholinergic stimulation on catecholamine release from the adrenal medulla were examined. Overall the results indicate that various aspects of the adrenal medulla become stable after 4 d of culture and the adrenal medulla at this stage releases catecholamines in response to cholinergic stimulation. The whole adrenal medulla culture system may be a useful tool for investigating catecholamine-related functions dependent on intercellular reactions or communications.

Effect of alendronate on risk of fracture in women with low bone density but without vertebral fractures: results from the Fracture Intervention Trial

CONTEXT

Alendronate sodium reduces fracture risk in postmenopausal women who have vertebral fractures, but its effects on fracture risk have not been studied for women without vertebral fractures.

OBJECTIVE

To test the hypothesis that 4 years of alendronate would decrease the risk of clinical and vertebral fractures in women who have low bone mineral density (BMD) but no vertebral fractures.

DESIGN

Randomized, blinded, placebo-controlled trial.

SETTING

Eleven community-based clinical research centers.

SUBJECTS

Women aged 54 to 81 years with a femoral neck BMD of 0.68 g/cm2 or less (Hologic Inc, Waltham, Mass) but no vertebral fracture; 4432 were randomized to alendronate or placebo and 4272 (96%) completed outcome measurements at the final visit (an average of 4.2 years later).

INTERVENTION

All participants reporting calcium intakes of 1000 mg/d or less received a supplement containing 500 mg of calcium and 250 IU of cholecalciferol. Subjects were randomly assigned to either placebo or 5 mg/d of alendronate sodium for 2 years followed by 10 mg/d for the remainder of the trial.

MAIN OUTCOME MEASURES

Clinical fractures confirmed by x-ray reports, new vertebral deformities detected by morphometric measurements on radiographs, and BMD measured by dual x-ray absorptiometry.

RESULTS

Alendronate increased BMD at all sites studied (P<.001) and reduced clinical fractures from 312 in the placebo group to 272 in the intervention group, but not significantly so (14% reduction; relative hazard [RH], 0.86; 95% confidence interval [CI], 0.73-1.01). Alendronate reduced clinical fractures by 36% in women with baseline osteoporosis at the femoral neck (>2.5 SDs below the normal young adult mean; RH, 0.64; 95% CI, 0.50-0.82; treatment-control difference, 6.5%; number needed to treat [NNT], 15), but there was no significant reduction among those with higher BMD (RH, 1.08; 95% CI, 0.87-1.35). Alendronate decreased the risk of radiographic vertebral fractures by 44% overall (relative risk, 0.56; 95% CI, 0.39-0.80; treatment-control difference, 1.7%; NNT, 60). Alendronate did not increase the risk of gastrointestinal or other adverse effects.

CONCLUSIONS

In women with low BMD but without vertebral fractures, 4 years of alendronate safely increased BMD and decreased the risk of first vertebral deformity. Alendronate significantly reduced the risk of clinical fractures among women with osteoporosis but not among women with higher BMD.

Differential antigen-stimulated proliferation of human mononuclear cells by recombinant Schistosoma japonicum antigens in a Chinese population

Peripheral blood mononuclear cells (PBMC) from 117 individuals living on two islands in an area (Dongting Lake) endemic for schistosomiasis japonica in China, and 15 control individuals from a non-endemic area of China, were assessed for antigen-stimulated proliferation against five recombinant Schistosoma japonicum antigens of recognized interest in the development of immunity to schistosomiasis. Two recombinant antigens, paramyosin and 28-kD glutathione-S-transferase, stimulated cellular proliferation (stimulation index > or = 3.0) in 38.5% and 42.5% of subjects, respectively, a level similar to that induced by a soluble whole parasite extract (51.3%). In contrast, three other recombinant antigens tested--a fatty acid binding protein, 22-kD tegumental membrane-associated antigen, and glyceraldehyde-3-phosphate dehydrogenase--stimulated PBMC proliferation in only 3-8% of subjects. Moreover, we also identified a positive association between the degree of exposure, and cellular proliferation following stimulation with recombinant paramyosin or whole parasite extract. Highly significant differences in antigen-stimulated proliferation were also observed between the two islands, Niangashan and Qingshan. The whole parasite extract stimulated proliferation in 90% of subjects from Niangashan island compared with only 42.1% of subjects from Qingshan island (chi2 = 16.88, P = 0.00004), while glutathione-S-transferase stimulated proliferation in 77.3% of subjects from Niangashan island compared with only 34.7% of subjects from Qingshan island (chi2 = 13.09, P = 0.003). A similar, but not significant, trend was observed for paramyosin and the fatty-acid binding protein. The identification of differential cellular proliferative responses to specific schistosome antigens within an infected human population may have important practical implications for vaccine development against schistosomiasis japonica.

Mapping of linear B-cell epitopes on the 14-kDa fatty-acid binding protein of Chinese Schistosoma japonicum

The 14-kDa fatty-acid binding protein (FABP) of schistosomes is of recognised importance as a potential vaccine and/or drug target against schistosomiasis, but little is known of its antigenicity. In this study, we have identified and compared linear B-cell epitopes present on the FABP of Chinese strain Schistosoma japonicum, using sera obtained from experimentally infected mice, or from mice immunised with the functionally active recombinant antigen (rSjFABP). Sera from three strains of mice, CBA, C57BL/6 and BALB/c, representing different genetic backgrounds, were reacted with a series of overlapping peptides in epitope-scanning studies. Sera from experimentally infected mice reacted predominantly with peptides 9-12, encoding amino acids 91-132, in the C-terminal region of the molecule. This was in contrast to sera from mice immunised with rSjFABP, which reacted predominantly with peptides 4-9, encoding amino acids 41-101, in the central portion of the molecule. The results presented here describing the epitope mapping of this molecule may prove important in research aimed at further defining immune responses to schistosomal antigens. They indicate that epitopes recognised during vaccination with functionally active rSjFABP, at least in the murine model, differ from those recognised during natural infection.

Gene expression of catecholamine synthesizing enzymes and beta adrenoceptor subtypes during rat embryogenesis

Timed-pregnant Sprague-Dawley rats were killed between gestational day (GD) 8 and 10, and embryos were explanted and separated into developmental stages according to a modified Theiler's system. Total RNA from each stage was isolated and subjected to reverse transcription-polymerase chain reaction (RT-PCR) assays to examine gene expression of catecholamine synthesizing enzymes and three subtypes of beta adrenoceptors. Expression of these genes was detected at much earlier stages than previously reported, and each enzyme and receptor subtype showed a different pattern of gene expression. For example, mRNA for tyrosine hydroxylase, the rate-limiting enzyme for catecholamine synthesis, was detected as early as stage 10a, late GD 8, before the neural crest cells appear (stage 12, mid GD 10). This contradicts the common belief that catecholamines are produced only in the cells of sympathoadrenal lineage which originate from the neural crest cells and the cells of central nervous system. Results from the present study indicate that catecholamine synthesis is not limited to the cells of sympathoadrenal lineage.

DNA-based vaccination using Schistosoma japonicum (Asian blood-fluke) genes

We have examined the efficacy of nucleic acid vaccination in inducing immunity to the multicellular parasite, Schistosoma japonicum, a trematode worm responsible for causing schistosomiasis in humans and other mammalian species. A panel of Schistosoma japonicum cDNAs were cloned into eukaryotic expression vectors, injected into animals, and tested for immunogenicity. The cDNAs tested encoded 26- and 28-kDa glutathione-S-transferases, calreticulin, glyceraldehyde-3-phosphate dehydrogenase, a 22.6 kDa membrane-associated antigen, a 14 kDa fatty-acid binding protein, fragments of paramyosin, full-length paramyosin, and a novel gene comprising the 26 kDa glutathione-S-transferase fused to a fragment of paramyosin cDNA. The paramyosin gene constructs, including the fusion, were all able to induce anti-paramyosin antibodies; with the fragments of paramyosin these were of the IgG1, IgG2a and IgG2b isotypes. In contrast, none of the other schistosome cDNAs tested were able to induce detectable antibody responses. The anti-paramyosin antibodies did not protect mice challenged with cercariae of S. japonicum.

Kaiser Colorado's Cooperative Health Care Clinic: a group approach to patient care

A Kaiser Permanente pilot project demonstrates that managing health status with patients on a group basis versus one-on-one office visits can improve health care delivery services and reduce unnecessary resource utilization. Kaiser's Cooperative Health Care Clinic (CHCC) in Denver, Colorado, uses a multidisciplinary team to successfully provide care to elderly members with chronic conditions.

Molecular genetic analysis of human cystic hydatid cases from Poland: identification of a new genotypic group (G9) of Echinococcus granulosus

We have used nuclear (ribosomal ITS1) and mitochondrial (ND1) sequences to characterize human and pig isolates of Echinococcus granulosus collected by fine needle aspiration biopsy (FNAB) in Poland. The data indicate clearly that the Polish patients were not infected with the common sheep strain (G1 genotype) of E. granulosus, normally associated with human cystic hydatid infection. Instead, the hydatid parasite infecting the Polish patients shares very similar ND1 sequence with the previously characterized pig (G7) genotype but it also exhibits some clear differences. In particular, E. granulosus DNA from the Polish patients amplified a single ITS1 fragment in PCR and distinct ITS1-RFLP patterns were obtained after restriction digestion. The form of hydatid isolated from the Polish patients appears, therefore, to represent a distinct, previously undescribed genotype (designated G9) of E. granulosus.

Validity of self-reported rheumatoid arthritis in elderly women

OBJECTIVE

To determine the validity of a self-reported physician diagnosis of rheumatoid arthritis (RA) in elderly women.

METHODS

Women with self-reported RA were contacted and permission requested to contact their physician. Physicians were mailed a questionnaire requesting information on the subject's arthritic condition. Hand radiographs obtained at study entry were read for changes of RA.

RESULTS

The self-reported diagnosis of RA could be confirmed in 26 (21%) individuals.

CONCLUSION

The positive predictive value of self-reported RA was low in this cohort. Caution needs to be exercised in the use and interpretation of self-report data concerning arthritic conditions in epidemiologic studies.