Structure and enzymatic properties of genetically truncated forms of the water-insoluble glucan-synthesizing glucosyltransferase from Streptococcus sobrinus.

Glucosyltransferase-I (GTF-I: 175 kDa) of a cariogenic bacterium, Streptococcus sobrinus 6715, mediates the conversion of water-soluble dextran (alpha-1,6-glucan) into a water-insoluble form by making numerous alpha-1,3-glucan branches along the dextran chains with sucrose as the glucosyl donor. The structures and catalytic properties were compared for two GTF-I fragments, GTF-I' (138 kDa) and GS (110 kDa). Both lack the N-terminal 84 residues of GTF-I. While GTF-I' still contains four of the six C-terminal repeats characteristic of streptococcal glucosyltransferases, GS lacks all of them. Electron microscopy of negatively stained samples indicated a double-domain structure for GTF-I', consisting of a spherical head with a smaller spherical tail, which was occasionally seen as a long extension. GS was seen just as the head portion of GTF-I'. In the absence of dextran, both fragments simply hydrolyzed sucrose with similar K(m) and k(cat) values at low concentrations (<5 mM). At higher sucrose concentrations (>10 mM), however, GTF-I' exhibited glucosyl transfer activity to form insoluble alpha-1, 3-glucans. So did GS, but less efficiently. Dextran increased the rate and efficiency of the glucosyl transfer by GTF-I'. On removal of the C-terminal repeats of GTF-I' by mild trypsin treatment, this dextran-stimulated transfer was completely lost and the dextran-independent transfer became less efficient. These results indicate that the N-terminal two-thirds of the GTF-I sequence are organized as a structurally and functionally independent domain to catalyze not only sucrose hydrolysis but also glucosyl transfer to form alpha-1,3-glucan chains, although not efficiently; the C-terminal repeat increases the efficiency of the intrinsic glucosyl transfer by the N-terminal domain as well as rendering the whole molecule primer-dependent for far more efficient insoluble glucan synthesis.

[Classification of pulmonary-function tests by principal component analysis].

The structure of pulmonary-function data obtained from 468 randomly selected subjects was analyzed. The subjects included patients with chronic bronchitis, bronchial asthma, chronic pulmonary emphysema, diffuse panbronchiolitis, and idiopathic interstitial pneumonitis, and normal health adults. From among the many possible indices of pulmonary function, 19 were chosen and were used as variables in principal component analysis. Six significant principal components (PCs) were extracted. The first three PCs accounted for 70% of the total information and were termed "ventilation," "volume," and "diffusion." The second three PCs accounted for 17% of the information and were termed "small airway," "lower airway," and "shape." Indices of ventilatory unevenness were not separated from indices of airway obstruction, and were included in the first PC. No other, unknown PC was detected with these pulmonary-function indices. The relationship among indices is displayed in a factor loading matrix, and pulmonary-function tests are classified statistically.

[Prognosis of idiopathic interstitial pneumonia].

Idiopathic interstitial pneumonia (IIP) is characterized by chronic inflammation and fibrosis of the lung. It carries a poor prognosis and the treatment for IIP has not yet been established. We evaluated 116 cases of IIP retrospectively, and analyzed possible prognostic factors, such as the mode of detection, clinical symptoms, chest X-ray findings, pulmonary function tests, blood chemistry, bronchoalveolar lavage (BAL), and treatments. The 5-year survival rate from the onset was 39.5% and the 10-year survival rate was only 12.7%. The 5-year survival rate from the appearance of dyspnea on exertion was 23.2% and 10-year survival rate was 9.0%. According to the results of the Kaplan-Meier analysis, patients with low% FVC (< 70%), those with high values of ESR, those with high values of CRP, and those with advanced chest X-ray shadows did not survive as long as other patients. Multivariate analysis with a proportional hazards model revealed that a high percentage of eosinophils in BALF was associated with a poor prognosis. Analysis with a logistic model revealed that being male having a low %DLCO were associated with a poor prognosis.

[A case of multiple broncholithiasis caused by mucus retention].

The patient was a 57-year-old male with long-standing bronchiectasis who developed severe respiratory failure and died in 1991. Autopsy revealed multiple broncholithiasis in both lungs, but no calcified lymph nodes in the hilar region. Since histological examination of the broncholiths showed only stratified structures but no tissue structure, most likely cause was considered to be calcification of mucus in the bronchi. Analysis of the stone components revealed 78% calcium and 22% protein. This patient represents a case of multiple broncholithiasis caused by mucus retention, which is thought to be very rare.

[Prediction formulas for pulmonary function tests expressed in linear and exponential form for healthy Japanese adults].

We studied 21 parameters of pulmonary function in 172 healthy Japanese adult smokers and non-smokers ranging from 18 to 83 years of age. Prediction formulas for each parameter were calculated in both linear and exponential form using multiple regression analysis with regard to sex, age, height and weight. The exponential form was superior to the linear form for V25, V50, PEF, FVC, VC, FEV1.0, FEV1.0%, TLC, DLCo and DL/VA, namely, the parameters whose predictive value decreases with aging. In particular for V25, only the exponential form of the predictive formula could be applied for subjects with advanced age. For PMI, LCI, IDI, pulmonary N2 clearance delay, and single breath delta N2, indices for unevenness of intrapulmonary gas distribution, there has been no previous report about their predictive formulas and ours is the first. These predictive formulas all showed increasing values with aging, and showed higher predictive values in females than in males, except for delta N2. These parameters require further study with respect to their normal value ranges and differences between males and females.

[Study of influence of respiratory rate to airway resistance in patients with pulmonary emphysema].

Application of the panting method is very difficult for patients with pulmonary emphysema (PE). We attempted to measure airway resistance (Raw) during quiet breathing and changing respiratory rate step by step in patients with PE using a pressure-type body plethysmograph system (BX-82) correcting measured values by temperature and humidity. Influence of the respiratory rate to Raw was studied at 0.5l/sec of inspiratory and expiratory flow. Whenever the respiratory rate was going up, the Raw increased in spite of the increase of the thoracic gas volume. Raw (2Hz) was about one and a half times as high as Raw (quiet breathing). On the other hand, when the respiratory rate was going up, elevation of the peak flow was always able to be recognized. It seemed that the state of the airway varied during the panting method. The Raw measured during 0.5 Hz breathing (nearly quiet breathing) had small variability. Because the airway state during 0.5 Hz breathing was nearly the same as that during quiet breathing, measurement of Raw (0.5Hz) can be regarded as a practical method in patients with PE.

A new D-stereospecific amino acid amidase from Ochrobactrum anthropi.

A new D-stereospecific amino acid amidase has been partially purified from Ochrobactrum anthropi SCRC SV3, which had been isolated and selected from soil. The Mr of the enzyme was estimated to be about 38,000, and its isoelectric point was 5.3. The enzyme catalyzes the stereospecific hydrolysis of D-amino acid amide to yield D-amino acid and ammonia. The major substrates included D-phenylalanine amide, D-tyrosine amide, D-tryptophan amide, D-leucine amide, and D-alanine amide.