Direct healthcare costs and predictors of costs in patients with primary Sjogren's syndrome.

OBJECTIVES: To analyse the healthcare usage, direct healthcare costs and predictors of cost in primary Sjögren's syndrome (PSS) in the UK and to compare the findings with the data from healthy control groups and rheumatoid arthritis (RA) patients. METHODS: A total of 129 patients with PSS (American-European criteria), 91 with RA and 92 controls, were included in the study. All groups were age-matched females and all completed questionnaires on health status (SF-36) and healthcare utilization (economic component of the Stanford Health Assessment Questionnaire). Annual direct healthcare costs were calculated (and expressed in 2004 UK pound sterling) and predictors of costs for each patient group were determined by regression analyses. Age, health status, disease duration and anti-Ro/La antibody positivity were used as potential predictor variables. RESULTS: Mean age was similar in the PSS (59.2 yrs, S.D. 11.6), RA (60.3 yrs, S.D. 10.5) and control groups (57.7 yrs, S.D. 12.5). The mean disease duration was 5.4 yrs (S.D. 4.8) in the PSS group and 13.4 yrs (S.D. 11.4) in the RA group. The mean annual total direct cost per patient [95% confidence interval (CI)] was 2188 pounds sterling (1831 and 2546 pounds sterling) in the PSS group, 2693 pounds sterling(2069 and 3428 pounds sterling) in the RA group and 949 pounds sterling (741 and 1156 pounds sterling) in the control group. The costs in the PSS group were greater than for the RA and control groups for visits to all healthcare professionals (total) as well as visits to the dentist, dental hospital and ophthalmologist. The costs in the PSS and RA groups were higher than in controls for diagnostic tests and visits to hospital and the accident and emergency (A&E) department. The PSS group also incurred higher costs than controls, but lower costs than the RA group, for visits to a rheumatologist, urine and blood tests, assistive devices and drug therapy. Regression analysis identified the SF-36 physical function subscale as the best predictor of costs in PSS patients as well as controls and the mental health subscale in RA patients. CONCLUSION: This is the first study to evaluate direct healthcare costs in patients with PSS. PSS has a significant impact on the healthcare system, similar to that of RA, by more than doubling costs compared with control patients.

The use of alternative medical therapies in patients with systemic lupus erythematosus. Trination Study Group.

OBJECTIVE: As part of an ongoing study of health resource utilization and diminished productivity in patients with systemic lupus erythematosus (SLE), the use of alternative medical therapies was assessed. METHODS: A cohort of 707 patients with SLE from 3 countries completed questionnaires on demographics, social support, health status (using the Short Form 36 health survey), satisfaction with health care, health resource utilization (conventional resources and alternative therapies), and time losses in labor market and non-labor market activities. Annual direct and indirect costs (1997 Canadian dollars) were calculated and compared for users and nonusers of alternative medical therapies. RESULTS: Among the 707 patients, 352 (49.8%) were found to use alternative therapies and at similar rates across Canada, the United States, and the United Kingdom. Users were younger and better educated than nonusers, exhibited poorer levels of self-rated health status and satisfaction with medical care, and had minimal to no objective evidence of worse disease (according to the revised Systemic Lupus Activity Measure instrument). The mean of log direct medical costs for conventional resources was higher for users of select alternative therapies compared with nonusers. In a logistic regression, neither the number of alternative therapies used nor the individual therapy increased the probability of incurring indirect costs. CONCLUSION: The use of alternative medical therapies is common in patients with SLE. Users of many alternative medical therapies accrue greater conventional medical costs compared with nonusers. The use of alternative medical therapy may be a marker for care-seeking behavior associated with higher consumption of conventional medical resources in the absence of demonstrable additional morbidity and should be considered in future cost analyses of patients with SLE.

A molecular description of mutations affecting the pollen component of the Nicotiana alata S locus.

Mutations affecting the self-incompatibility response of Nicotiana alata were generated by irradiation. Mutants in the M1 generation were selected on the basis of pollen tube growth through an otherwise incompatible pistil. Twelve of the 18 M1 plants obtained from the mutagenesis screen were self-compatible. Eleven self-compatible plants had mutations affecting only the pollen function of the S locus (pollen-part mutants). The remaining self-compatible plant had a mutation affecting only the style function of the S locus (style-part mutant). Cytological examination of the pollen-part mutant plants revealed that 8 had an extra chromosome (2n + 1) and 3 did not. The pollen-part mutation in 7 M1 plants was followed in a series of crosses. DNA blot analysis using probes for S-RNase genes (encoding the style function of the S locus) indicated that the pollen-part mutation was associated with an extra S allele in 4 M1 plants. In 3 of these plants, the extra S allele was located on the additional chromosome. There was no evidence of an extra S allele in the 3 remaining M1 plants. The breakdown of self-incompatibility in plants with an extra S allele is discussed with reference to current models of the molecular basis of self-incompatibility.

Molecular characterisation of a cDNA sequence encoding the backbone of a style-specific 120 kDa glycoprotein which has features of both extensins and arabinogalactan proteins.

Nicotiana alata has a style-specific hydroxyproline-rich glycoprotein (the 120 kDa glycoprotein) which has properties of both extensins and AGPs [19, 20]. The 120 kDa glycoprotein is a soluble component in the extracellular matrix of the transmitting tract of styles where it accounts for ca. 9% of the total buffer-soluble protein. Here we describe the molecular cloning of a cDNA representing the gene NaPRP5 which encodes the backbone of the 120 kDa glycoprotein. Expression of mRNA is restricted to styles, consistent with observations on the distribution of the 120 kDa glycoprotein. Levels of accumulation of the transcript encoding the 120 kDa protein backbone are not altered significantly by pollination with either compatible or incompatible pollen. The protein backbone of the 120 kDa glycoprotein, as predicted by the cDNA sequence, is composed of three distinct domains. The sequence of these domains, together with linkage analysis of the carbohydrate component of the 120 kDa glycoprotein, allows predictions of the likely distribution of substituent glycosyl chains along the protein backbone. The similarity of the C-terminal domains of the 120 kDa glycoprotein and GaRSGP, the galactose-rich style glycoprotein of N. alata, is consistent with the two molecules sharing a common antigenic domain in their backbones [31]. The sharing of domains between distinct hydroxyproline-rich glycoproteins suggests that identification of a glycoprotein of this class solely by its protein or carbohydrate epitope is not valid.

Molecular characterisation of an S-like RNase of Nicotiana alata that is induced by phosphate starvation.

We characterised a cDNA encoding an S-like RNase (RNase NE) from the styles of the self-incompatible plant, Nicotiana alata. RNase NE is 86% identical to an extracellular RNase from tomato cell cultures, RNase LE. DNA hybridisation experiments indicate that there are ca. 5-6 sequences related to RNase NE in the N. alata genome and that RNase NE is not linked to the self-incompatibility (S) locus. RNase NE is expressed in the styles, petals and immature anthers but not in the vegetative tissues of N. alata plants under normal growth conditions. Under phosphate-limited conditions, RNase NE expression is induced in roots but not leaves of N. alata. A transcript hybridising to RNase NE is also induced in N. plumbaginifolia cell cultures in response to phosphate starvation. RNase NE is likely to play a role in the response of N. alata to phosphate limitation, possibly by scavenging phosphate from sources of RNA in the root environment. We also discuss the evolutionary relationships between the S- and S-like RNase genes in plants.

Self-incompatibility in flowering plants.

Fertilization in flowering plants begins with a pollen grain bearing the male gametes landing on the female stigma. Several mechanisms enable the stigma to discriminate between the different types of pollen that it may receive, of which the best studied is self-incompatibility. The molecules that regulate self-incompatibility are well characterized in two plant families, the Solanaceae and Brassicaceae. This list has recently been extended to include candidates for self-incompatibility molecules from the Rosaceae, Papaveraceae and Poaceae. The information provided by the sequences of these molecules gives insight into the mechanisms and evolution of self-incompatibility in the different families of flowering plants.

Molecular cloning of cDNAs encoding the protein backbones of arabinogalactan-proteins from the filtrate of suspension-cultured cells of Pyrus communis and Nicotiana alata.

This paper reports the isolation of cDNAs encoding the protein backbone of two arabinogalactan-proteins (AGPs), one from pear cell suspension cultures (AGPPc2) and the other from suspension cultures of Nicotiana alata (AGPNa2). The proteins encoded by these cDNAs are quite different from the 'classical' AGP backbones described previously for AGPs isolated from pear suspension cultures and extracts of N. alata styles. The cDNA for AGPPc2 encodes a 294 amino acid protein, of which a relatively short stretch (35 amino acids) is Hyp/Pro rich; this stretch is flanked by sequences which are dominated by Asn residues. Asn residues are not a feature of the 'classical' AGP backbones in which Hyp/Pro, Ser, Ala and Thr account for most of the amino acids. The cDNA for AGPNa2 encodes a 437 amino acid protein, which contains two distinct domains: one rich in Hyp/Pro, Ser, Ala, Thr and the other rich in Asn, Tyr and Ser. The composition and sequence of the Pro-rich domain resembles that of the 'classical' AGP backbone. The Asn-rich domains of the two cDNAs described have no sequence similarity; in both cases they are predicted to be processed to give a mature backbone with a composition similar to that of the 'classical' AGPs. The study shows that different AGPs can differ in the amino acid sequence in the protein backbone, as well as the composition and sequence of the arabinogalactan side-chains. It also shows that differential expression of genes encoding AGP protein backbones, as well as differential glycosylation, can contribute to the tissue specificity of AGPs.

Isolation of the protein backbone of an arabinogalactan-protein from the styles of Nicotiana alata and characterization of a corresponding cDNA.

Arabinogalactan-proteins (AGPs) from the styles of Nicotiana alata were isolated by ion exchange and gel filtration chromatography. After deglycosylation by anhydrous hydrogen fluoride, the protein backbones were fractionated by reversed-phase HPLC. One of the protein backbones, containing mainly hydroxyproline, alanine, and serine residues (53% of total residues), was digested with proteases, and the peptides were isolated and sequenced. This sequence information allowed the cloning of a 712-bp cDNA, AGPNa1. AGPNa1 encodes a 132-amino acid protein with three domains: an N-terminal secretion signal sequence, which is cleaved from the mature protein; a central sequence, which contains most of the hydroxyproline/proline residues; and a C-terminal hydrophobic region. AGPNa1 is expressed in many tissues of N. alata and related species. The arrangement of domains and amino acid composition of the AGP encoded by AGPNa1 are similar to that of an AGP from pear cell suspension culture filtrate, although the only sequence identity is at the N termini of the mature proteins.

S-RNase gene of Nicotiana alata is expressed in developing pollen.

In the solanaceous plant Nicotiana alata, self-incompatibility is controlled by a single, multiallelic locus (S locus) expressed in both pollen and pistil. Previously, we have shown cosegregation between alleles of the S locus and alleles of a gene that encodes a glycoprotein with ribonuclease activity (S-RNase). Furthermore, expression of the S-RNase gene is apparently confined to the pistil and is correlated with the onset of self-incompatibility. In this paper, we report that the S-RNase gene is also expressed at low levels in developing pollen. A transcript in developing pollen hybridized to a cDNA encoding the S2-RNase allele of the parent plant and did not hybridize to cDNAs encoding other S-RNase alleles. Two cDNAs for the S2-RNase were cloned from a library derived from anthers of a plant homozygous for the S2 allele and both corresponded to the coding sequence of the S2-RNase. The product of the S-RNase gene was detected by immunocytochemistry in the intine of mature, hydrated pollen grains. These results are interpreted in the light of current knowledge of the structure of the S locus.