Biomedical subjects

R A Shaw

Publications and source records attributed to R A Shaw.

At least 19 recordsLinked to original sources

PubMed2006

Integration of microfluidics with biomedical infrared spectroscopy for analytical and diagnostic metabolic profiling.

We describe how infrared spectroscopy of dry films (IRDF) can provide diagnostic information, and how we expect integration with laminar fluid diffusion interface (LFDI) sample pre-processing to generate new analytical and diagnostic tests. LFDI pre-processing provides sample clean-up and analyte separation. The sensitivity of IRDF to certain analytes is enhanced through the depletion of sample constituents that otherwise obscure relevant spectral features, permitting the deposition of films with larger sample volumes and, hence, of greater effective optical pathlength for the targeted analytes. An integrated LFDI-IRDF technology holds promise both as a method for rapid point-of-care quantitative analysis of biological fluids and as the engine of discovery for a wide range of novel diagnostic methods based upon metabolic profiling. In particular, successful integration will provide a versatile and cost effective technology platform that will allow for the accurate quantification of low-concentration analytes that are otherwise inaccessible and will provide the basis for diagnostic and prognostic methods that would otherwise be impossible. The specific question addressed by the proof-of-concept study summarised here is whether the spectra of LFDI processed samples can provide analytical methods that are more accurate than otherwise possible without LFDI pre-processing. The enrichment of serum creatinine is accomplished, with subsequent enhancement of its spectral contribution permitting quantification of this clinically important analyte beyond that achievable with no pre-processing. Finally, to illustrate the potential in diagnostic applications, two recently initiated studies are outlined, one involving chronic kidney disease and the other for chronic and acute coronary artery disease.

Biomarkers↗

PubMed2005

Bioaccessibility of arsenic in soils developed over Jurassic ironstones in eastern England.

Jurassic ironstones outcropping over parts of eastern England give rise to soils with arsenic concentrations in excess of the UK soil guideline value of 20 mg kg(-1) for residential areas. Total arsenic concentrations were determined for 73 ironstone derived soils and bioaccessible arsenic determined using an in vitro physiologically based extraction test. The bioaccessible arsenic concentration for these soils was found to be well below the soil guideline value with a mean concentration of 4 mg kg(-1) and a range of 2-17 mg kg(-1). The bioaccessible fraction ranges from 1.2 to 33%. Data from a sequential extraction test based on the use of aqua regia as the main extractant is presented for a subset of 20 of the soils. Chemometric data reduction is used to demonstrate that the bioaccessible arsenic is mainly contained within calcium iron carbonate (sideritic) assemblages and only partially iron aluminosilicates, probably berthierine, and iron oxyhydroxide phases, probably goethite. It is suggested that the bulk of the non-bioaccessible arsenic is bound up with less reactive iron oxide phases.

Aluminum Silicates↗

PubMed2001

Analysis of pulmonary surfactant by Fourier-transform infrared spectroscopy following exposure to Stachybotrys chartarum (atra) spores.

Lung cells are among the first tissues of the body to be exposed to air-borne environmental contaminants. Consequently the function of these cells may be altered before other cells are affected. As gas exchange takes place in the lungs, changes in cellular function may have serious implications for the processes of oxygen uptake and carbon dioxide elimination. In order for these processes to occur, the lung must maintain a high degree of expandability. This latter function is accomplished in part by the pulmonary surfactant which is synthesized and released by alveolar type II cells. Earlier studies have shown that exposure to gas phase materials such as smoke or organic solvents can alter the composition and function of the surfactant. The present study examines the ability of highly toxigenic mold spores to alter surfactant composition. Stachybotrys chartarum spores suspended in saline were instilled into mouse trachea as described earlier. After 24 h, the lungs were lavaged and the different processing stages of surfactant isolated by repeated centrifugation. Intracellular surfactant was isolated from the homogenized lung tissue by centrifugation on a discontinuous sucrose gradient. Samples were extracted into chloroform-methanol, dried and analyzed by Fourier-Transform infrared spectroscopy (FTIR). Exposure to S. chartarum induced an overall reduction of phospholipid among the three surfactant subfractions. The intermediate and spent surfactant fractions in particular were reduced to about half of the values observed in the saline-treated group. The relative distribution of phospholipid was also altered by spore exposure. Within the intracellular surfactant pool, higher levels of phospholipid were detected after spore exposure. In addition, changes were observed in the nature of the phospholipids. In particular strong intramolecular hydrogen bonding, together with other changes, suggested that spore exposure was associated with absence of an acyl chain esterified on the glycerol backbone, resulting in elevated levels of lysophospholipid in the samples. This study shows that mold spores and their products induce changes in regulation of both secretion and synthesis of surfactant, as well as alterations in the pattern of phospholipid targeting to the pulmonary surfactant pools.

Animals↗

PubMed2000

Noninvasive assessment of cardiac ischemic injury using (87)Rb and (23)Na MR imaging, (31)P MR, and optical spectroscopy.

The aim of the study was to compare and analyze different noninvasive indices of cell damage in the isolated pig heart model of regional ischemia. We used (23)Na and (87)Rb MR imaging to evaluate Na(+)/K(+) balance, (31)P MR spectroscopy to measure energetics, and optical spectroscopy to assess oxymyoglobin (MbO(2)). Hearts were subjected to 120-min occlusion of the left anterior descending artery and were then reperfused for 120 min. Reperfusion resulted in an increase in (23)Na (37 +/- 18% of the posterior wall) and decrease in (87)Rb (55 +/- 15%) image intensities, partial recovery of PCr, ATP, the total phosphates, and MbO(2) in the anterior wall. The above changes are consistent with the irreversible cell damage in the anterior wall, confirmed by lack of staining with triphenyltetrazolium chloride. Changes in Na(+) and Rb(+) in the infarct area inversely correlated and their ratio is a more sensitive index of cell injury than either of them alone.

Animals↗

PubMed2000

In vivo optical/near-infrared spectroscopy and imaging of metalloproteins.

A number of medical applications of near-infrared spectroscopy are growing closer to clinical acceptance, and new techniques involving both spectroscopy and imaging are evolving rapidly. In vivo spectroscopy and, more recently, imaging techniques are largely based upon optical electronic transitions involving the metal centers of hemoglobin (blood), myoglobin (muscle) and cytochrome aa3 (mitochondria). The wide variety of near-IR based applications includes heart and stroke research, monitoring cerebral oxygenation of premature babies, and 'functional activation' (response of brain to mental tasks). All of these applications are founded upon changes in hemoglobin O2 saturation; these changes are monitored by following trends in the near-infrared absorptions of deoxyhemoglobin (760 nm) and oxyhemoglobin (920 nm). The same absorptions provide a basis for imaging regional variations in blood oxygenation. This report presents and discusses examples, both from the literature and from our recent work, of near-infrared spectroscopy and imaging in medical applications.

Animals↗

PubMed2000

Comparison of infrared spectroscopic and fluorescence depolarization assays for fetal lung maturity.

OBJECTIVE: Infrared spectroscopic analysis of amniotic fluid was recently shown to be a potential useful method for the determination of fetal lung maturity. Those studies used thin-layer chromatography as a reference method for the calibration of the infrared-based technique. However, thin-layer chromatography is compromised by large intra-assay and interlaboratory coefficients of variation. Therefore in this study we have used a reference method that is based on fluorescence depolarization, the TDx FLM II assay, to verify the sensitivity and precision of infrared spectroscopy for assessment of fetal lung maturity status. STUDY DESIGN: Samples of amniotic fluid were obtained by amniocentesis from 101 patients between the 24th and 40th weeks of pregnancy. Small volumes (35 microL) of amniotic fluid specimens were dried, and the infrared spectra were measured with a commercial infrared spectrometer. The fetal lung surfactant/albumin ratio was determined separately for each specimen with the TDx FLM II assay. The proposed infrared method was then calibrated and tested with a partial least-squares regression analysis to quantitatively correlate the infrared spectra with the surfactant/albumin ratios provided by the TDx FLM II assays. RESULTS: A total of 144 training spectra were used to build the partial least-squares calibration model. The correlation coefficient for the training set was excellent (r = 0.92), with an SE between infrared-predicted and reference surfactant/albumin ratios of 17 mg/g. The model was then validated on a set of 69 test spectra and yielded an SE of 14 mg/g (r = 0.86). The final partial least-squares model included the 900- to 1500-cm(-1) and 2800- to 3200-cm(-1) spectral ranges and 6 partial least-squares factors. CONCLUSION: Because the infrared-based fetal lung maturity measurements correlated well with assays from both of the current standard clinical techniques (thin-layer chromatography and fluorescence depolarization) and the procedure is less labor and training intensive, we concluded that infrared spectroscopy has the potential to emerge as the method of choice for prediction of fetal lung maturity from amniotic fluid analysis.

Albumins↗

PubMed2000

Calcium phosphate-containing precipitate and the carcinogenicity of sodium salts in rats.

Sodium saccharin, ascorbate and other sodium salts fed at high doses to rats produce urinary bladder urothelial cytotoxicity with consequent regenerative hyperplasia. For sodium salts that have been tested, tumor activity is enhanced when administered either alone or after a brief exposure to a known genotoxic bladder carcinogen. These sodium salts alter urinary composition of rats resulting in formation of an amorphous precipitate. We examined the precipitate to ascertain its composition and further delineate the basis for its formation in rat urine. Using scanning electron microscopy with attached X-ray energy dispersive spectroscopy, the principal elements present were calcium, phosphorus, minor amounts of silicon and sulfur. Smaller elements are not detectable by this method. Infrared analyses demonstrated that calcium phosphate was in the tribasic form and silicon was most likely in the form of silica. Small amounts of saccharin were present in the precipitate from rats fed sodium saccharin (<5%), but ascorbate was not detectable in the precipitate from rats fed similar doses of sodium ascorbate. Large amounts of urea and mucopolysaccharide, apparently chondroitin sulfate, were detected in the precipitate by infrared analysis. Chemical analyses confirmed the presence of large amounts of calcium phosphate with variably small amounts of magnesium, possibly present as magnesium ammonium phosphate crystals, present in urine even in controls. Small amounts of protein, including albumin and alpha(2u)-globulin, were also detected (<5% of the precipitate). Calcium phosphate is an essential ingredient of the medium for tissue culture of epithelial cells, but when present at high concentrations (>5 mM) it precipitates and becomes cytotoxic. The nature of the precipitate reflects the unique composition of rat urine and helps to explain the basis for the species specificity of the cytotoxic and proliferative effects of high doses of these sodium salts.

Animals↗

PubMed1999

Infrared spectroscopy of exfoliated cervical cell specimens. Proceed with caution.

OBJECTIVE: To determine whether diagnostic information may be recovered from the infrared spectra of exfoliated cell specimens by using a novel spectral feature extraction method, in conjunction with linear and quadratic discriminant analysis, for spectral classification. STUDY DESIGN: Over 800 infrared spectra were included in the study, with corresponding clinical diagnoses based upon cytology and, when available, histology reports. Three sets of classification trials were carried out with the aim of distinguishing the spectra corresponding to normal specimens from CIN 1, 2 and 3. For each of these three cases, the procedure was to: (1) develop a set of provisional classification models using only a "training" subset of the spectra, and (2) test each provisional model by its ability to correctly predict the diagnoses on the basis of the remaining spectra. RESULTS: For optimal classification trials, training set classification accuracies were 68% for normal/CIN 1, 73% for normal/CIN 2 and 81% for normal/CIN 3; for the corresponding test sets the classification accuracies were 60%, 60% and 67%, respectively. CONCLUSION: The infrared spectra of exfoliated cervical cells carry information regarding the presence or absence of dysplasia, and that information is recoverable--albeit imperfectly at this stage--from the spectra of "real life" cell preparations.

Algorithms↗

PubMed1998

Infrared spectroscopic analysis of biomedical specimens using glass substrates.

We report on the use of glass substrates for the infrared spectroscopic analysis of dried serum, amniotic fluid, and synovial fluid films. New analytical applications of infrared spectroscopy are emerging rapidly, spurred largely by ever-improving instrumentation, combined with the widespread availability of powerful chemometric methods. We have recently begun to focus upon potential applications in both clinical chemistry and medical diagnostics. For example, serum analysis, the determination of fetal lung maturity, and the differential diagnosis of arthritis have all recently been demonstrated to be feasible on the basis of the infrared spectra of films dried from the appropriate samples (serum, amniotic fluid, or synovial fluid). However, the transition from the laboratory into clinical usage hinges on the availability of IR-transparent substrates that are both inexpensive and readily obtainable. We have demonstrated in this study that despite limited transparency in the IR region, clinical analyses and diagnostic spectral classifications may nevertheless be carried out using glass as a substrate for the IR measurements.

Amniotic Fluid↗

PubMed1998

Multianalyte serum analysis using mid-infrared spectroscopy.

This study assesses the potential for using mid-infrared (mid-IR) spectroscopy of dried serum films as the basis for the simultaneous quantitation of eight serum analytes: total protein, albumin, triglycerides, cholesterol, glucose, urea, creatinine and uric acid. Infrared transmission spectra were acquired for 300 serum samples, each analysed independently using accepted reference clinical chemical methods. Quantitation methods were based upon the infrared spectra and reference analyses for 200 specimens, and the models validated using the remaining 100 samples. Standard errors in the IR-predicted analyte levels (Sy/x) were 2.8 g/L (total protein), 2.2 g/L (albumin), 0.23 mmol/L (triglycerides), 0.28 mmol/L (cholesterol), 0.41 mmol/L (glucose) and 1.1 mmol/L for urea, with correlation coefficients (IR vs reference analyses) of 0.95 or better. The IR method emerged to be less suited for creatinine (Sy/x = mumol/L) and uric acid (Sy/x = 140 mumol/L) due to the relatively low concentrations typical of these analytes.

Blood Chemical Analysis↗

PubMed1997

Infrared spectroscopy of human apolipoprotein fragments in SDS/D2O: relative lipid-binding affinities and a novel amide I assignment.

Infrared absorption spectra are reported for six apolipoprotein fragments in SDS/D2O. Five of the peptides correspond to proposed lipid-binding domains of human apolipoproteins [apoC-I(7-24), apoC-I(35-53), apoA-II(18-30)+, apoA-I(166-185), apoE(267-289)], and the sixth is the de novo lipid associating peptide LAP-20. The amide I infrared absorption patterns are generally consistent with predominantly helical structures (as determined previously by NMR spectroscopy and distance geometry calculations) and further suggest that apoA-I(166-185) and apoE(267-289) are bound to SDS relatively weakly in comparison to the other four peptides. The latter conclusion is also supported by the temperature dependence of the infrared spectra, as increasing temperature promotes a distinct increase in random coil structure only for apoA-I(166-185) and apoE(267-289). In addition to features readily ascribed to helices, the infrared spectra of all the peptides show absorptions in the spectral region 1630-1635 cm-1 that is usually associated with beta-structure, a motif that is clearly absent from the NMR-derived structures. Parallel difficulties also arose in the analyses of the circular dichroism spectra. We suggest that both the low-frequency infrared absorptions and the ambiguities in interpreting the CD spectra may be due to unusual structures at the peptide C-termini, involving C=O groups that form hydrogen bonds simultaneously either with two solvent molecules or with donors from the backbone (NH) and the solvent (OH). Analogous absorptions may be a general feature of solvent-exposed helices, which suggests a need for caution in assigning amide I bands below 1640 cm-1.

Amino Acid Sequence↗

PubMed1997

Natural behavior polymorphism due to a cGMP-dependent protein kinase of Drosophila.

Naturally occuring polymorphisms in behavior are difficult to map genetically and thus are refractory to molecular characterization. An exception is the foraging gene (for), a gene that has two naturally occurring variants in Drosophila melanogaster food-search behavior: rover and sitter. Molecular mapping placed for mutations in the dg2 gene, which encodes a cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). Rovers had higher PKG activity than sitters, and transgenic sitters expressing a dg2 complementary DNA from rover showed transformation of behavior to rover. Thus, PKG levels affected food-search behavior, and natural variation in PKG activity accounted for a behavioral polymorphism.

Animals↗

PubMed1997

Oxygen regulation of energy metabolism in isolated pig hearts: a near-IR spectroscopy study.

UNLABELLED: Intracellular pO2 in cardiac muscle is determined by the balance between its diffusion from vascular (VS) to intracellular space (IS) and uptake by mitochondria. Cessation of mechanical work decreases O2 demand and should reduce the O2 gradient between VS and IS. In this work, the effects of arterial pO2 (pO2a) on myoglobin (Mb) oxygenation, O2 uptake and lactate formation rates [V(O2) and V(Lac), micromol/min/g wet weight, respectively] in beating and KCl-arrested pig hearts were compared. pO2a was decreased stepwise (five steps, 10 min/step) from 528+/-24 to 54+/-19 mmHg by changing the ratio of O2/CO2 (95:5%) to N2/CO2 (95:5%) in the gas mixture from 100/0 through 50/50, 25/75, 10/90 to 0/100. While recording mechanical function, visible/near-infrared (near-IR) spectra (400-2500 nm) were acquired from the left ventricular wall every 45 s (32 scans) using a fiber-optic light guide connected to an NIRSystems spectrometer. Relative MbO2 in the epicardium + midmural layer and the epicardium was estimated from absorbance changes (second derivative) at 764 and 584 nm, respectively. In beating hearts, a decrease in pO2a resulted in a decrease in MbO2 (similar in both layers) and V(O2) (from 1.26+/-0.15 to 0.22+/-0.10) and an increase in V(Lac) from 0 to 2.43+/-0.76. In arrested hearts an increase in V(Lac) (0.55+/-0.24) was observed only at the lowest pO2a and the Mb oxygenation curve was shifted towards lower vascular pO2 [(pO2a+pO2v)/2] by ;160 mmHg. Oxygen consumption (oxygen flux) correlated linearly with calculated values of the oxygen gradients between the vascular and cytoplasmic spaces in both beating and arrested hearts. However, the diffusion rate constant was 3.5 times lower in arrested hearts. CONCLUSIONS: (1) hypoxia in KCl-arrested hearts results in only moderate activation of anaerobic glycolysis; (2) oxygenation of the epicardial and midmural LV layers is similar; and (3) a large pO2 gradient exists between VS and IS in beating and arrested crystalloid-perfused hearts.

Adenosine Triphosphate↗

PubMed1997

Abnormal thyroid function tests in infants with congenital hypothyroidism: the influence of soy-based formula.

OBJECTIVE: To assess the etiology of hyperthyroxinemia or hyperthyrotropinemia in infants with congenital hypothyroidism who are on replacement therapy with L-thyroxine. METHODS: These infants were treated with recommended doses of L-thyroxine following the diagnosis of congenital hypothyroidism. Because of hyperthyroxinemia (2 patients) and hyperthyrotropinemia (1 patient), medication compliance and dietary practice (formula type, age of introduction, and discontinuation or change of the formula) were assessed. Clinical evaluation was also performed. RESULTS: Elevated thyroxine level in 2 infants was associated with discontinuation of soy formula 4 weeks previously; reduction of L-thyroxine dose normalized serum levels in both of these infants. In the third infant, who received soy formula from 1 week of age, TSH remained elevated despite incremental L-thyroxine doses of 19 micrograms/kg/day; discontinuation of soy formula was followed by normalization of the TSH in 3 weeks and helped attain a subsequent decrement of L-thyroxine dose to 8.6 micrograms/kg/day. Neither the hyperthyroxinemia nor hyperthyrotropinemia in these infants was associated with any adverse behavioral-developmental consequence. CONCLUSION: When initiating soy-formula feeding in infants with congenital hypothyroidism, the L-thyroxine dose should be increased because of significant reduction in intestinal absorption: conversely, when soy feeding is discontinued, the L-thyroxine dose should be decreased.

Congenital Hypothyroidism↗

PubMed1996

Quantitation of protein, creatinine, and urea in urine by near-infrared spectroscopy.

OBJECTIVES: To determine the feasibility of near-infrared analysis for quantitating urea, creatinine, and protein in urine. Practical advantages of this method include ease of sample presentation and the absence of reagents or disposables. DESIGN AND METHODS: The near-infrared methods were developed by first measuring the spectra of 123 different urine samples and, using independent clinical analyses, determining the protein, creatinine, and urea levels in each. Calibration models relating near-infrared spectroscopic features to those independently determined concentrations were optimized, and each model then validated using a set of 50 additional samples. RESULTS: Standard errors of calibration were 14.4 mmol/L, 0.66 mmol/L, and 0.20 g/L, and standard errors of prediction 16.6 mmol/L, 0.79 mmol/L, and 0.23 g/L, respectively, for urea, creatinine, and protein. CONCLUSIONS: Near-infrared urea quantitation is as accurate as the reference method, enzymatic (urease) conductivity, used here for calibration. Creatinine analysis is slightly less accurate relative to the reference (Jaffe rate) method; however, these errors can be minimized by careful attention to factors affecting precision. The accuracy of the near-infrared protein analysis cannot approach that of the reference method; nevertheless, the technique is potentially useful for coarse screening and for quantifying protein levels above 0.3 g/L.

Calibration↗

PubMed1996

Turn conformations in peptides containing the -Xaa-Ser- sequence.

The conformations of the protected dipeptides Boc-L-Pro-L-Ser-NHMe, Boc-L-Pro-D-Ser-NHMe, Boc-L-Val-L-Ser-NHMe and Boc-L-Val-D-Ser-NHMe have been explored through interpretation of their infrared spectra in CH2Cl2, DMSO and D2O solution. In CH2Cl2 solution the formation of a ten-membered ring (beta-turn) for each compound is signaled by characteristic shifts in both the urethane C = O and the terminal NH stretching frequencies. For each peptide, differences in the amide I absorption patterns for LL and LD isomers are consistent with the formation of type I and type II beta-turns respectively in CH2Cl2 solution. The amide I absorptions suggest substantial disruption of intramolecular hydrogen bonding in DMSO, and no intermolecular hydrogen bonding whatsoever in aqueous solution. In CH2Cl2 solution the OH stretching vibration is consistent with the formation of a hydrogen bond to the C = O of the serine group; however, two additional absorptions at frequencies characteristic of "free' OH groups also appear in all spectra. Implications regarding the serine in stabilizing the beta-turn are discussed.

Absorption↗

PubMed1996

Infrared spectroscopy of dystrophic mdx mouse muscle tissue distinguishes among treatment groups.

Four groups of mdx mice (deflazacort, high dose of 1.5 mg/kg and low dose of 0.75 mg/kg; prednisone, 1.0 mg/kg; and a placebo) were examined in a double-blind protocol. The experiments tested the hypothesis that infrared spectroscopy can distinguish among gastrocnemius muscle tissues derived from dystrophic animals (n = 22) from different treatment groups and from control muscle tissue (n = 23). Results showed that muscle, inflamed muscle, and tendon can be distinguished on the basis of their infrared absorption patterns. Distinctions among the spectra of the four treatment groups were sought with automated pattern-recognition methods. These classification methods, based either on spectral regions (900-1,500 cm-1) or on principal-component analysis, were in close agreement, assigning 15 or 16, respectively, of 22 mdx spectra to the correct treatment group. Both trials cleanly separated the high-dose deflazacort from the placebo group of muscles, whereas the prednisone and low-dose deflazacort groups were persistently confused in these classifications. Changes in the histology of muscle inflammation paralleled the spectral-classification results. Thus the proposed method, combining infrared spectroscopy with pattern-recognition algorithms, can distinguish treatment effects on muscle tissue. Specific spectral features characteristic of tissue type, disease progression, and treatment effects are not yet elucidated.

Algorithms↗

PubMed1995

Arthritis diagnosis based upon the near-infrared spectrum of synovial fluid.

Synovial fluid aspirates have been characterized by measuring their visible/near-infrared spectra (400-2500 nm). The hypothesis tested in this study is that the spectra contain sufficient information to serve as an aid in the diagnosis and/or staging of arthritic disorders. The concentrations of all major constituents are carried implicitly in the spectra, and in this sense this approach is similar in spirit to conventional synovial fluid analysis. The distinguishing feature of this method is that we have not converted the raw data (spectra) explicitly to analytical information. Rather, we have used automated pattern recognition methods to identify significant characteristics of the spectra themselves. A total of 109 spectra were measured and split into three classes according to the disease (osteoarthritis, rheumatoid arthritis, or spondyloarthropathy) affecting the patient from whom the synovial fluid sample was taken. An automated classification method was then trained by correlating features derived from these spectra to the clinical diagnoses. The robustness of the classification was validated using the leave-one-out cross-validation method, i.e., by training on all but one of the spectra and using the resulting model to predict the classification for the spectrum that is left out. The result derived by following this procedure for each of the spectra was that 105 of the 109 predicted classifications correctly matched the clinical diagnosis. These results suggest that the near-infrared spectrum of synovial fluid is sufficient to allow diagnosis of the disease affecting the joint from which the aspirate is drawn.

Arthritis, Rheumatoid↗