Clinical application of a new latex photometric immunoassay reagent, LPIA-GENESIS D-dimer, and its performance in patient-derived plasma samples

Introduction

We previously reported an antibody MIF‐220 that recognizes a specific structure induced on the surface of thrombin‐activated E‐domain of one fibrin molecule bound with the D‐domains of other fibrinogen/fibrin molecules. Utilizing MIF‐220, we produced a test kit for cross‐linked fibrin degradation products (XDP), LPIA‐GENESIS D‐dimer (LG‐DD), and evaluated basic performance characteristics for clinical application. We then attempted to apply LG‐DD to see its eligibility in clinical plasma samples.

Method

The characteristic performances requested for clinical use were studied including limit of quantitation, within‐run imprecision, day‐to‐day imprecision, antigen excess, interference study, and method comparison with LPIAACE‐Ddimer (ACE‐DD) available on the market.

Results

The performance characteristics were all satisfactory. Extraordinarily high concentrations of XDP are occasionally obtained by ACE‐DD in samples with collection problems, but not by LG‐DD, indicating that a certain XDP species present in the former was not measured by LG‐DD. Structural studies suggested that the “B‐b” set of polymerization sites must be involved as well in the maintenance of cross‐linked fibrin in vivo.

Conclusion

LG‐DD was able to measure a wide range of XDP, that is, 0.20‐35.0 μg FEU/mL that covers the levels of XDP in most of the clinical samples. LG‐DD was found to almost avoid false‐positive results noticed in samples as mentioned above, and this feature seems to be preferable to established kits for the measurement of XDP.

Rapid assay for plasma soluble E-selectin predicts the development of acute respiratory distress syndrome in patients with systemic inflammatory response syndrome

A newly developed rapid immunoassay method for plasma soluble E-selectin (sES) was examined to determine whether it can predict the development of acute respiratory distress syndrome (ARDS) in critically ill patients with systemic inflammatory response syndrome (SIRS). Plasma levels of sES were measured on admission (day 1) to the emergency unit. Development of various types of organ failures including ARDS was compared in the first 5 days of admission (from day 1 to day 5) between patients with normal plasma levels of sES and those with elevated plasma levels of sES. Plasma levels of sES were determined using a newly developed latex agglutination method that takes 20 min to obtain the test results. The normal range of the plasma sES level was 4.8-29.7 ng/mL with this method. Among the patients examined, 22 patients showed elevated sES levels (D(A)E group) and 28 showed normal sES levels (D(A)N group). Development of ARDS was significantly higher in the D(A)E group (15/22, 68.2%) than in the D(A)N group (4/28, 14.3%) (P < 0.001) and that of cardiovascular system failure, renal failure, and coagulation system failure was also significantly higher in the D(A)E group than in the D(A)N group. The mortality rate at 28 days after admission was higher in the D(A)E group (27.3%) than in the D(A)N group (0%) (P < 0.05). Determination of sES levels by this new rapid assay method might be useful for prediction of the development of ARDS in critically ill patients with SIRS, a pathologic condition that has the potential risk for development of multiple organ failure.

The changes occurring after the Putti-Platt procedure using magnetic resonance imaging

The purpose of this study is to evaluate the magnetic resonance imaging (MRI) following Putti-Platt procedure for recurrent anterior dislocation of the shoulder. Six shoulders of six patients who had received Putti-Platt procedure were evaluated by the MRI before and after operation. After the Putti-Platt procedure the subscapularis tendon was thickened and an increased signal area on T2-weighted images were observed in four patients. The area of subscapularis tendons after operation was increased maximally 3.46-fold and the volume was increased on average 1.51-fold. The course of subscapularis muscle fiber before operation was described as a mild arc, but changed to a straight line after the procedure in five patients. The findings in this study suggest that the Putti-Platt procedure leads to a remarkable increase in strength of subscapularis tendon and an improvement of laxity of subscapularis muscle. In conclusion, there is a good possibility that this procedure will increase the stability of the glenohumeral joint and be a successful treatment for recurrent anterior dislocation of the shoulder.

Incomplete tears of the subscapularis tendon associated with tears of the supraspinatus tendon: cadaveric and clinical studies

This study was undertaken to evaluate incomplete tears of the subscapularis tendon that occur in conjunction with small or medium-sized tears of the supraspinatus tendon. Fifty-two shoulders were examined in 26 embalmed cadavers. The average age at the time of death was 76.3 years. Rotator cuff tears were observed in 32 (61.5%) shoulders. Six (11.5%) shoulders had massive rotator cuff tears and were excluded from the study, leaving 46 shoulders for study. Twenty shoulders had a tear of the supraspinatus tendon, and 17 had a tear of the subscapularis tendon. All tears of the subscapularis tendon were articular-side incomplete tears. On histologic examination most pathologic changes of the subscapularis tendon were observed on the articular side of the upper portion. Lesions of the long head of the biceps brachii were identified in 14 (30.4%) shoulders. A statistically significant correlation was found between tears of the subscapularis tendon and the presence of lesions of the long head of the biceps brachii (P=.0014). In addition, the results of preoperative magnetic resonance imaging of 15 patients (average age, 62.9 years) with a surgically confirmed diagnosis of incomplete tears of the subscapularis tendon in conjunction with tears of the supraspinatus tendon were also evaluated. Incomplete tears of the subscapularis tendon could be identified on magnetic resonance imaging as an area of high signal intensity on axial T2-weighted images in all 15 shoulders studied.

Electromyographic analysis of shoulder joint function of the biceps brachii muscle during isometric contraction

Surface electromyography was performed for both heads of the biceps brachii in 11 healthy men while the muscles were under 30% maximum isometric shoulder flexion and abduction. Elbow related biceps activity was minimized by using a brace locked in neutral forearm rotation. Electromyographic activity was normalized as a percentage of maximal muscle contraction during 24 shoulder motions. Electromyographic activity was detected in all motions examined, suggesting that the biceps muscle acts as a flexor and an abductor of the shoulder. Both heads of the biceps muscle had higher activities during external rotation than during internal rotation for most motions. Activities of both heads increased with arm elevation, but showed little dependence on elbow position. The long head was still active during internal rotation of the shoulder. These findings also suggest that the biceps muscle is a flexor and an abductor of the shoulder, and that the long head can act as a humeral head stabilizer in superior and anterior directions. Muscle fatigue of the biceps and the deltoid muscle also was determined at 30% of maximum isometric flexion. All muscles had significantly decreased mean power frequency and turns count, and increased amplitude and integrated electromyography. The rate of decrease in mean power frequency was larger for the biceps than for the deltoid muscle, and the rate of increase in amplitude was larger for the long head of the biceps than for the short head or for the deltoid muscle. These findings suggest that the long head of the biceps must increase its mechanical output to keep the arm in elevation to a greater extent than do the short head and the deltoid muscle. This may be one of the causes of tendinitis or rupture of the long head.

Morphologic changes in long head of biceps brachii in rotator cuff dysfunction

Morphologic changes in the long head of the biceps brachii (LHB) and bicipital groove associated with cuff tears were studied in 170 cadavers. In specimens with minimum or moderate cuff tears, the primary finding was relative stenosis at the bicipital groove induced by enlargement of the LHB. However, this stenosis was not apparent in specimens with massive cuff tears and in these specimens, the medial wall of the groove exhibited wear and tear, a potential cause of LHB instability. We suggest that the long head of the biceps brachii muscle can potentially compensate for inadequate rotator cuff function. This increasing activity could lead to enlargement of the tendon and cause deterioration of the bicipital gliding mechanism.

[Anatomical study on the atrophy of supraspinatus muscle belly with cuff tear]

We dissected the 76 shoulders in 38 cadavers to investigate changes in the supraspinatus muscle with a cuff tear and correlated these with age. We made a transverse section in the supraspinatus muscle and stained the section by the van Gieson method. Then we analyzed the changes in the supraspinatus muscle belly with the cuff tear, and by age, measuring the short and long diameter of a slice of the muscle belly and the area of tendon fiber. In the group with a normal cuff, there was a negative correlation between age and the short diameter of the slice of the supraspinatus muscle but no significant correlation between the age and the long diameter of the slice. In the group with a cuff tear, not only the short diameter but also the long diameter of the slice of the supraspinatus muscle decreased with increase in the length of the cuff defect. We concluded that measuring the long diameter of the slice of the supraspinatus muscle was more efficient than measuring the short diameter to evaluate muscle atrophy with a cuff tear. The area of the tendon in the slice increased with the length of cuff defect. The increased area of the tendon may have been responsible for reducing the elasticity in the supraspinatus muscle with a cuff tear.

Rapid quantitative evaluation of plasma D-dimer levels in thrombotic states using an automated latex photometric immunoassay

To evaluate a recently developed latex photometric immunoassay (LPIA) that which can measure 40 samples quantitatively within 30 minutes, we measured D-dimer levels in blood samples obtained from patients with disseminated intravascular coagulation (DIC). Linearity of D-dimer determination was shown over the range from 0.5 to 36 micrograms/ml, and recovery studies demonstrated 94 to 108% recovery. The intra-assay and inter-assay coefficients of variation ranged from 0.6 to 11.3% at plasma D-dimer levels of 0.54 to 30.1 micrograms/ml. No interference by lipids, bilirubin, haemoglobin, rheumatoid factor, or gamma-globulin was noted. The normal D-dimer range was less than 0.5 microgram/ml in healthy ambulatory subjects, while the level in elderly subjects with atherosclerosis (14%) or in immobilized subjects (38%) was well above this limit. There was a strong correlation between plasma and serum D-dimer levels (r = 0.993). D-dimer levels measured by this LPIA showed a good correlation with those determined using two kinds of ELISA. The LPIA D-dimer levels were elevated in some subjects with diseases predisposing to DIC, but remained below 10.0 micrograms/ml. On the other hand, the LPIA D-dimer levels in DIC subjects were almost always above 10.0 microgramS/ml. Our study showed that a hypercoagulable state should be suspected when the LPIA D-dimer level is greater than 0.5 microgram/ml and that DIC should be diagnosed when the level is greater than 10.0 micrograms/ml in the presence of an appropriate underlying disease. This LPIA system can rapidly evaluate the presence of a hypercoagulable state as accurately as any ELISA, and thus seems potentially valuable for both emergency and routine laboratory use.

[Evaluation of clinical usefulness of a rapid quantitative measurement of D dimer (cross-linked fibrin degradation products)]

In order to evaluate precisely the fibrinolytic states in clinical disorders, plasma levels of D dimer (cross-linked fibrin degradation products) were measured by a newly developed, rapid quantitative method based on the latex photometric immunoassay in patients with hematological malignancies, diabetes mellitus, collagen disease, liver disease, thrombotic disease and disseminated intravascular coagulation (DIC). Plasma levels of D dimer were elevated in a variety of diseases, especially in DIC. Patients with hematological malignancies, liver disease and thrombotic disease also had relatively high levels of D dimer. On the whole, D dimer values were positively correlated with plasmin-alpha 2-plasmin inhibitor complex and thrombin-antithrombin III complex. In addition, plasma D dimer was measured during fibrinolytic therapy with urokinase or tissue-type plasminogen activator; its elevation was detected in some patients. These findings indicate that accelerated fibrinolysis is frequently observed in a variety of diseases, and that a rapid quantitative measurement of D dimer would be valuable for the precise assessment of fibrinolysis in these disease states.

Recalcitrant chronic adhesive capsulitis of the shoulder. Role of contracture of the coracohumeral ligament and rotator interval in pathogenesis and treatment

Seventeen patients who had recalcitrant chronic adhesive capsulitis were operated on between 1979 and 1986 and were followed for an average of 6.8 years. At operation, the major cause of the restricted glenohumeral movement was found to be contracture of the coracohumeral ligament and rotator interval. Release of the contracted structures relieved pain and restored motion of the shoulder in all patients. Histological study showed fibrosis, hyalinization, and fibrinoid degeneration in the contracted connective tissues, as well as fibrosis of the subsynovial tissue and an absence of the synovial cell layer on the joint side of the rotator interval. The contracture of the coracohumeral ligament and rotator interval appears to be the main lesion in chronic adhesive capsulitis. Resection of these structures, combined with appropriate exercise, will relieve pain and restore motion to the shoulder.