Yoshikazu Inoue

Evaluation of serum KL-6 levels in patients with pulmonary tuberculosis

SETTINGnKL-6, a human MUC-1 mucin preferentially expressed on type II pneumocytes, is a sensitive serum marker for evaluating alveolar damage of interstitial pneumonia and pulmonary fibrosis. Some patients with pulmonary tuberculosis develop severe respiratory dysfunction caused by extensive pulmonary fibrosis, compensatory emphysema and fibrous pleural thickening.nnnOBJECTIVEnTo evaluate the clinico-pathological significance of KL-6 in pulmonary tuberculosis.nnnDESIGNnSerum KL-6 levels were measured in sera from 57 patients with active pulmonary tuberculosis and 38 healthy controls by a sandwich-type enzyme-linked immunosorbent assay. Immunohistochemistry was performed by an avidin-biotin-peroxidase complex method.nnnRESULTSnKL-6 levels were significantly higher in the patients than in the healthy controls (518 +/- 693 [SD] vs 227 +/- 91 U/ml, P < 0.001) and increased significantly according to the extent of pulmonary lesions evaluated by chest X-ray (P < 0.001). There was a significant negative correlation between serum KL-6 levels and % vital capacity (VC) (r = 0.642, P < 0.05). KL-6 was strongly expressed on proliferated type II pneumocytes and cuboidal epithelial cells adjacent to thickened intralobular septa and pleura.nnnCONCLUSIONSnIn pulmonary tuberculosis, serum KL-6 originates from proliferated type II pneumocytes and cuboidal epithelial cells, and is a useful marker presenting the degree and extent of pulmonary fibroproductive lesions.

Evaluation of soluble IL-6 receptor concentration in serum and epithelial lining fluid from patients with interstitial lung diseases.

We measured soluble IL‐6 receptor (sIL‐6R) levels in serum and bronchoalveolar lavage fluids (BALF) from patients with interstitial pneumonia of unknown etiology (IP) (n= 17), sarcoidosis (n= 8) and normal control subjects (n= 10), to investigate its role in pulmonary diseases. Soluble IL‐6R was determined by an ELISA. The volume of epithelial lining fluid (ELF) in BALF was estimated using an urea method. We found that levels of sIL‐6R in serum, BALF, and ELF from patients with IP or sarcoidosis were significantly higher than those from normal subjects. Furthermore, levels of sIL‐6R in BALF or ELF were significantly correlated with those of albumin, indicating that sIL‐6R, together with albumin, may enter ELF as a result of the increased permeability caused by pulmonary inflammation. Thus most of the sIL‐6R in ELF would be from serum, and relatively small amounts of it might be produced locally. However, sIL‐6R levels in ELF, but neither serum nor BALF, were significantly correlated with levels of C‐reactive protein in patients with IP. These results suggest that both systemic and local production of sIL‐6R are increased, and raised sIL‐6R is involved in the modulation of systemic and local inflammatory responses in patients with IP and sarcoidosis.

Effect of SQ29,852, a new angiotensin converting enzyme (ACE) inhibitor with a phosphonic acid group, on the activity of angiotensin converting enzyme from human kidney

1. An in vitro experiment was carried out to compare the inhibitory effect of SQ29,852 on human renal angiotensin converting enzyme (ACE) with those of captopril, enalapril and enalaprilat. 2. SQ29,852 strongly inhibited human renal ACE; its IC50 value was 1.5 x 10(-8) M. In terms of the IC50, SQ29,852s efficacy was about 1/10 of that of captopril and 1/28 of that of enalaprilat, but it was about 14 times more potent than enalapril. 3. SQ29,852 showed no inhibitory effects on cathepsin D, urinary kallikrein, renal renin, pepsin, trypsin and chymotrypsin. Its ACE-specificity was higher than that of captopril. 4. ACE inhibition by SQ29,852 was shown to be competitive, as revealed by Lineweaver-Burk plots. The affinity of SQ29,852 to ACE was shown to be high by a Ki value of 1.2 x 10(-8) M.

Direct radioimmunoassay of angiotensin-converting enzyme in sera from patients with pulmonary diseases

The concentration of angiotensin-converting enzyme (ACE) was measured in the sera of 47 normal subjects and 108 patients with various pulmonary diseases by radioimmunoassay (RIA) using antiserum to human kidney ACE and homogeneous human kidney ACE as a tracer. The immunologic identity of ACE in the sera from a normal subject and a patient with active sarcoidosis was demonstrated by parallel logit-log transformation of displacement curves in the RIA. The activity and the enzyme concentration in normal and clinical samples correlated well (r=0.78,P<0.001). The mean concentration of ACE in normal serum was 320.9±105.2 ng/ml (mean ±1 SD, n=47). Serum ACE concentration in patients with active sarcoidosis (823.4±209.7, n=13) and in patients with silicosis (569.5±183.8, n=21) was significantly higher than in normals, and the ACE activity in the serum of both groups increased parallel to the concentration. In contrast, patients with active pulmonary tuberculosis (508.5±159.4, n=11) and with lung cancer (481.1±169.5, n=12) had significantly higher serum ACE concentrations (P<0.005) although the serum ACE activity did not increase. The specific activity of both groups (40.4±7.0 and 39.6±7.1 µmol/min/mg, respectively) was lower than that of normal subjects (50.0±12.8). A low ACE activity and a normal ACE concentration in patients with diffuse panbronchiolitis (n=8) and chronic bronchitis (n=6) resulted in a significantly low specific activity (37.4±13.0 and 36.2±7.3, respectively).

Immunohistologic Characterization of Angiotensin Converting Enzyme in the Human Kidney Using Monoclonal and Polyclonal Antibodies

Angiotensin converting enzyme (ACE; EC 3.4.15.1), or kininase II, plays an important role in the regulation of blood pressure by converting angiotensin I to the vasopressor angiotensin II, and by inactivating the depressor substance bradykinin (Erdos, 1976). The enzyme is mainly localized on the luminal surface of vascular endothelial cells of the lung or other tissues (Caldwell et al.,1976; Ryan et al., 1976; Takada et al., 1982). In addition to the endothelial localization, the enzyme is present on other types of cells including epithelial cells of renal proximal tubule, small intestine and testis, and neuroepithelial cells of the brain (Caldwell et al.,1976; Ryan et al.,1976; Takada et al., 1982; Defendini et al.,1983). Recent studies have demonstrated that testis of the rabbit and brain of the rat contain isoforms of ACE (El-Dorry et al., 1982; Strittmatter et al., 1985). Recently, we have developed monoclonal antibodies against human kidney ACE. In the present study, we examined the binding specificity of monoclonal antibody to ACE in the human kidney and lung by immunofluoresent method in comparison with that of the polyclonal antibody against human kidney ACE.

Radioimmunoassay of glandular kallikrein in human plasma after partial purification by immunoaffinity column

Glandular kallikrein in human plasma was partially purified by immunoaffinity column (1.0 X 2.0 cm) and was measured by a radioimmunoassay (RIA). Plasma (5-10 ml) was diluted with an equal volume of 10 mmol/l sodium phosphate buffer, pH 7.4, containing 0.9% NaCl (PBS) and was applied to an immunoaffinity column from which glandular kallikrein was eluted with 3 mol/l NaSCN (20 ml). The enzymic fraction was concentrated with an Amicon PM 10 filter and dialyzed against PBS. The final recovery of the enzyme was 51.6 +/- 1.6% (mean +/- SD), determined by using [125I]kallikrein. The usable range of the standard curve covered 2.5-100 ng/tube. The coefficient of variation within the series was 5.9%, and the coefficient of variation between the series was 7.6%. In healthy controls (n = 25), the plasma content of glandular kallikrein was 1.36 +/- 0.39 ng/ml. In patients with acute pancreatitis (n = 6), the plasma concentration was 8.02 +/- 6.15 ng/ml, significantly different from the control group (p less than 0.01).