Dissociation and recombination between ligands and heme in a CO-sensing transcriptional activator CooA. A flash photolysis study

CooA from Rhodospirillum rubrum is a transcriptional activator in which a heme prosthetic group acts as a CO sensor and regulates the activity of the protein. In this study, the electronic relaxation of the heme, and the concurrent recombination between ligands and the heme at approximately 280 K were examined in an effort to understand the environment around the heme and the dynamics of the ligands. Upon photoexcitation of the reduced CooA at 400 nm, electronic relaxation of the heme occurred with time constants of 0.8 and 1.7 ps. The ligand rebinding was substantially completed with a time constant of 6.5 ps, followed by a slow relaxation process with a time constant of 173 ps. In the case of CO-bound CooA, relaxation of the excited heme occurred with two time constants, 1.1 and 2.4 ps, which were largely similar to those with reduced CooA. The subsequent CO recombination process was remarkably fast compared with that of other CO-bound heme proteins. It was well described as a biphasic geminate recombination process with time constants of 78 ps (60%) and 386 ps (30%). About 10% of the excited heme remained unligated at 1.9 ns. The dynamics of rebinding of CO thus will help us to understand how the physiologically relevant diatomic molecule approaches the heme binding site in CooA with picosecond resolution.

[Primary Sjögren's syndrome with pulmonary hypertension]

A 50-year-old woman was admitted to our hospital because of dyspnea on exertion. A chest X-ray film showed cardiomegaly and echocardiography revealed right-heart overload. Right heart catheterization studies revealed pulmonary hypertension and no signs of pulmonary embolism or vasculitis. The patient had complained of Raynaud's phenomenon since 6 years before admission. She did not notice eye or mouth dryness, but examination of a lip-biopsy specimen showed infiltration of lymphocytes into the salivary glands. Laboratory findings showed hypergammaglobulinemia and hemolytic anemia. Primary Sjögren's syndrome with pulmonary hypertension was diagnosed. Her general condition improved with steroid pulse therapy followed by oral administration of corticosteroids and cyclophosphamide.

Cystic pulmonary metastases of endometrial stromal sarcoma of the uterus, mimicking lymphangiomyomatosis: a case report with immunohistochemistry of HMB45

A case of endometrial stromal sarcoma (ESS) showed cystic pulmonary metastases mimicking lymphangiomyomatosis (LAM). A 58-year-old female, who had undergone total hysterectomy for low-grade ESS 16 years previously, had repeated bouts of pneumothorax. Multiple thin-walled cysts in the peripheral lung were revealed by radiological examinations. In an open-lung biopsy specimen, cystic lesions were surrounded by layers of spindle-shaped cells of varying thickness that resembled LAM. However, in addition to subtle histologic differences from LAM, HMB45 (antimelanoma antibody) showed positive in LAM (n = 3), but was negative in ESS (n = 2) and the cystic lesions of this case. Using myogenic markers (desmin and alpha-smooth muscle actin), metastatic ESS could be immunohistochemically differentiated from mesenchymal cystic hamartoma (n = 1). HMB45 immunohistochemistry is useful in the differential diagnosis of cystic pulmonary lesions.

[Cardiac sarcoidosis]

To analyze the clinical features of cardiac sarcoidosis, we reviewed case reports and clinical investigations from Japan and other countries. Female patients were more frequently affected in this disease in Japan. Cardiac sarcoidosis is characterized by a high incidence of complete atrioventricular block, right bundle branch block, and ventricular arrhythmias on the electrocardiogram. Echocardiography often reveals left ventricular dilatation with systolic dysfunction and wall thickening or thinning. Radionuclide testings, such as, thallium-201, gallium-67 or technetium-99m pyrophosphate, are useful for detecting cardiac involvement and evaluating efficacy of corticosteroid therapy in patients with sarcoidosis. Most of the patients died due to recurrent or refractory heart failure. It is noteworthy that cases of sudden death during stable cardiac function have become infrequent.

Bilateral giant bullae with rapidly increasing fluid in the right bulla following operation: report of a case

A 33-year-old Japanese male was admitted to our hospital for the treatment of left pneumothorax. He was found to have bilateral giant bullae. Retention of fluid was observed in the right giant bulla. The fluid accumulated rapidly directly after bullectomy and excision of the left giant bullae. This suggested the existence of some mechanisms of fluid retention other than an infection of the bulla alone after operation.

Pleural lipoma: report of a case

We report herein the unusual case of a 45-year-old Japanese man whose chest X-rays revealed an abnormal shadow, increasing in size. A chest wall tumor was suspected, based on the findings of computed tomography (CT) of the thorax, the CT number of which was -137, chest roentgenogram, and an echograph. An open biopsy was performed to establish the final diagnosis. The resected tumor was a pedunculated pleural mass, yellowish in color, the pathological diagnosis of which confirmed a lipoma. Intrathoracic lipomas are rare, but pleural lipomas are seen even less frequently. CT, echography, and percutaneous needle biopsy have been found useful for diagnosing intrathoracic lipomas, but these examinations are not always adequate for confirming the final diagnosis. Consequently, tumor resection is essential for obtaining a pathological diagnosis.

[Oxygen-conserving delivery system]

Three methods for improving oxygen delivery efficiency--transtracheal oxygen therapy (TTO), reservoir cannula, and demand-pulse oxygen delivery--are currently available. We discuss our experiences of TTO and its characteristics compared with the other two methods. Since 1988, we have tried to apply TTO to the candidates for home oxygen therapy (HOT) fulfilling the following criteria: 1) good activity and enthusiasm to daily life, 2) high oxygen flow rate with nasal cannula, 3) complicating nasal disorders such as chronic sinusitis, or 4) suffering complications from nasal cannula therapy. We used a disposable 8-Fr feeding tube for a trnastracheal catheter. Patients were taught to change their catheters themselves every day by simply removing the old and reinserting the new catheter. We have experienced nine patients on HOT with TTO. A half to a third of the flow rate of nasal cannular was required with TTO to achieve an equivalent PaO2 level. In cases with hypercapnea, a persistent significant increase of PaCO2 was not found. We measured arterial blood gases, changing the distance from the tract opening to the catheter tip, and it was suggested that in each case there may be an optimum distance to achieve the highest PaO2 level. Seven cases received TTO for more than 18 months, a mean of 30.2 months (range 19.3-48.9) and HOT for a mean of 26.6 months. They all maintained a high degree of enthusiasm for TTO. Two cases could return to work. Five cases enjoyed active daily lives, such as shopping, going out for recreation, travelling, and attending concerts.(ABSTRACT TRUNCATED AT 250 WORDS)

[Assessment of the permeability of the pulmonary microvasculature using radiotracers in a case of adult respiratory distress syndrome]

A 48-year-old man with small cell lung cancer developed ARDS, and massive pulmonary edema fluid was obtained with the fiberoptic bronchoscopy. The pulmonary edema fluid to serum ratios of total protein and albumin were 0.72 and 0.85 respectively. The ratio of LDH was higher (2.71), while that of cholesterol was lower (0.11) than that of total protein. Simultaneously, isopropyl N [I-123] p iodoamphetamine (I-123 IMP) and I-131 human serum albumin (I-131 HSA) were injected into this patient. Samples of blood and pulmonary edema fluid were collected to measure the clearance through the pulmonary microvasculature. The time activity curves of I-123 IMP and I-131 HSA in his blood samples revealed almost constant radioactivity from 5 minutes to 120 minutes after injection, while both radioactivity levels in pulmonary edema fluid samples increased with time. The clearance ratio of I-123 IMP to I-131 HSA was constant at each sampling time (mean +/- SD, 1.51 +/- 0.32). The linear correlation between I-123 IMP clearance and I-131 HSA clearance (r = 0.95, p less than 0.01) suggested that the clearance ratio of exudative plasma components may remain unchanged even if pulmonary microvasculature permeability has changed.

[Double filtration plasmapheresis in case of Goodpasture's syndrome]

This article describes a case of Goodpasture's syndrome controlled by double filtration plasmapheresis (DFPP) combined with steroid and immunosuppressant therapy. A 48-year-old male, clerk, complaining of fever, dry cough and macroscopic hematuria, was admitted to our hospital. Microscopic hematuria was first pointed out at age 40 on an annual check up. His laboratory data on admission revealed severe anemia, azothemia, macroscopic hematuria and proteinuria. His chest radiograph and CT revealed diffuse nodular densities in bilateral lung fields. Specimens obtained by transbronchial lung biopsy and open renal biopsy revealed linear deposition of IgG by direct immunofluorescent antibody methods. Circulating antiglomerular basement membrane antibody level determined with radioimmunoassay was 1.8% on admission, but one week later it elevated to 5.6% with progression of dyspnea, hypoxemia, and renal failure. Steroid pulse therapy and a total of 6 double filtration plasmaphereses were performed in the first month. Subsequently hypoxemia and dyspnea disappeared, and the chest radiograph of the 40th hospital day showed no abnormal shadows. Two months later recurrence of pulmonary hemorrhage was noticed. Immunosuppressant administration (Cyclophosphamide 100 mg/day) and a total of 10 DFPP procedures were performed with success. By DFPP, circulating anti-GBM antibody fell rapidly to within normal ranges, and anti-GBM antibody level elevated in removed plasma. We think DFPP is effective to remove circulating anti-GBM antibody in Goodpasture's syndrome.

[Distribution of N-isopropyl-p-[I-123]iodoamphetamine among the peripheral blood components: an in vitro study]

With the purpose to clarify dynamics of N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP) in the blood stream its binding to the peripheral blood components was determined by in vitro experiment. I-123 IMP was added to the peripheral venous blood obtained from healthy volunteers to be incubated for different length of time (0-30 min) at 37 degrees C. The blood was then separated into blood cells and plasma. From the latter platelet rich plasma were separated. Radioactivity in each blood component was counted in a well type scintillation counter respectively. To evaluate the affinity of I-123 IMP to red blood cell the component containing blood cells were washed repeatedly with salines. It was found that the fraction of radioactivity in the blood cell component was 68.0 +/- 6.3% (m +/- 1 S.D.), which was higher than that in the plasma (32.0% +/- 6.3%). The radioactivity in the platelet-rich plasma was only 1.7 +/- 1.1% of the total I-123 IMP activity. This percentage did not change by the incubation time. When Tc-99m DTPA was incubated with blood, radioactivity in the blood cell component was only 22.5%, which is further lowered by 32 +/- 2.1% after each washing to reach 6.8% after three times washing. In contrast the radioactivity of I-123 IMP in blood cell component remained as high as 31.1% after eight times washing. Almost constant fraction (8.20 +/- 0.57%) of radioactivity was freed into supernate by each washing. These findings suggest that a certain specific binding mechanism is involved in the binding of I-123 IMP to red blood cells.

[A study on the intrapulmonary kinetics of N-isopropyl-p-[I-123]-iodoamphetamine in patients with interstitial lung diseases--assessment of disease activity by dynamic scintigraphy and regional clearance curve]

Aiming at clinical application of N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) to lung diseases intrapulmonary kinetics of I-123 IMP was studied. Dynamic lung scintigraphy was performed after intravenous injection of 3 MBq I-123 IMP in six normal volunteers and twenty patients with interstitial lung diseases. Simultaneously data were acquired in a data processor with 60-sec intervals over the period of 60 min. Time-activity curves of two areas of each lung field were obtained to calculate k values by monoexponential fitting method. In patients with interstitial lung diseases k values were significantly decreased (p less than 0.001) (0.995 X 10(-2) +/- 0.26 X 10(-2) as compared with those (1.602 X 10(-2) +/- 0.24 X 10(-2) in normal volunteers. For the assessment of capillary blood volume in the lung Tc-99m Sn colloids (SN) were given i.v. before I-123 IMP in 16 patients. There was a high correlation between regional uptake ratio of I-123 IMP and Tc-99m Sn colloids (SN) both at 1 min (n = 64; r = 0.91) and 25 min (n = 64; r = 0.93) after injection. The k values of IMP clearance curves were correlative to diffusing capacity at rest for CO (DLCO) (r = 0.71, p less than 0.01), vital capacity (r = 0.53, p less than 0.05) and forced expiratory volume in 1 sec (r = 0.58, p less than 0.05). These results suggest that the lung clearance of I-123 IMP reflect the severity of the endothelial cell injury which cause decrease in the capillary blood volume in interstitial lung diseases. Dynamic lung scintigraphy with I-123 IMP should prove useful for monitoring disease activity of interstitial lung diseases providing a new parameters to assess a non-respiratory lung function.

[An early stage case of pulmonary lymphangiomyomatosis]

A 35-year-old unmarried woman was admitted to our hospital because of right pneumothorax. Pulmonary lymphangiomyomatosis was suspected from CT and transbronchial lung biopsy findings. The diagnosis was confirmed histologically by open lung biopsy. As her biopsy specimen showed positive findings for both estrogen and progesterone receptor, tamoxifen administration was started. The CT revealed multiple cystic lesions (5-10 mm in diameter) but otherwise normal vascular structures and normal lung density. The plain chest radiograph showed no abnormalities. CT is very useful for the early detection of pulmonary lymphangiomyomatosis.