Angiotensin-converting enzyme activity by canine pulmonary microvascular and central pulmonary artery endothelial cells exposed to hypoxia

To compare the amount of angiotensin-converting enzyme (ACE) activity in pulmonary artery endothelial cells from different sites and to examine the effect of severe hypoxia (less than 1% of O(2) in 5% CO(2) and 95% N(2)) on the ACE activity expressed by these cells, endothelial cells were harvested and cultured from canine main pulmonary artery by scraping the luminal surface of the artery and from canine pulmonary artery microvessels by infusing chilled buffer with microcarrier beads and 0.02% ethylenediamine tetraacetic acid (EDTA). ACE activity in cell lysates and culture medium was evaluated by fluorometric assay with hippuryl-L-histidyl-L-leucine as a substrate. ACE activity in cell lysates and postculture medium of pulmonary microvascular endothelial cells (PMVEC) was higher than in cell lysates and culture medium of central pulmonary artery endothelial cells (PAEC). However, hypoxia suppressed cellular ACE activity in both PAEC and PMVEC. The degree of suppression of ACE activity by hypoxia, which was determined as (ACE activity in normoxia - ACE activity in hypoxia)/ACE activity in normoxia x 100(%), was larger in PMVEC than in PAEC. The pulmonary microvasculature may be a greater source of ACE than central pulmonary artery, and the ACE activity of pulmonary microvascular endothelial cells seem to be sensitive to hypoxia, although the small diameter of the vessels improves conditions for interaction of blood-borne substance with endothelial enzymes.

Cardiac output measurement by thoracic electrical bioimpedance in a patient with ovarian hyperstimulation syndrome

A 31-year-old woman developed severe ovarian hyperstimulation syndrome (OHSS) after exogenous gonadotropin stimulation for an in vitro fertilization program. Because of refusal of invasive monitoring, thoracic electrical bioimpedance (TEB) was performed to evaluate cardiac function and volume status. TEB pointed out decreased cardiac output (CO: 4.23 liters/min), cardiac index (CI: 2.63) and stroke volume (SV: 57.5 ml/beat). Serial monitoring of hemodynamic variables was then performed. After the data were obtained, fluid management was performed, and the patient recovered from abnormal homeostasis in 3 days. The hemodynamic variables returned to the normal range (CO: 6.85 liters/min, CI: 4.25, SV: 100.5 ml/beat) within the first 24 h. There were no complications such as life-threatening multiple organ failure. We discuss the usefulness of TEB for the fluid management of severe OHSS, as well as its implications.

Arachidonic acid metabolites and glucocorticoid regulatory mechanism in cultured porcine tracheal smooth muscle cells

To elucidate the signal transduction system in the production of prostaglandin E2 (PGE2) by porcine tracheal smooth muscle cells in culture (PTSMC), we examined the pattern of arachidonic acid metabolites released from PTSMC and the relationship between bradykinin-stimulated rises in intracellular calcium concentration ([Ca2+]i) and PGE2 production by PTSMC. We next examined the effect of dexamethasone on these parameters. Bradykinin induced a dose-dependent increase in both the rise in [Ca2+]i and PGE2 production by PTSMC. The increase in [Ca2+]i paralleled an increase in PGE2 production. High-performance liquid chromatography (HPLC) revealed that dexamethasone-treated PTSMC were suppressed to release arachidonic acid metabolites such as PGE2 and prostaglandin F2 alpha (PGF2 alpha). Incubation of PTSMC with 10(-6)M dexamethasone for 24 h significantly suppressed both the rise in [Ca2+]i and PGE2 production by PTSMC in response to bradykinin, and also significantly suppressed bradykinin-stimulated release of radioactivity from PTSMC prelabeled with 3H-labeled arachidonic acid (3H-AA). When PTSMC pretreated with dexamethasone were incubated with 170 nM prostaglandin H2 (PGH2) or 20 microM arachidonic acid; PTSMC synthesized less PGE2 than control PTSMC. Results suggest that bradykinin stimulates PTSMC to produce PGE2 via the signal transduction system including Ca2+, and dexamethasone appeared to suppress PGE2 production by reducing the activity of cytosolic phospholipase A2 (cPLA2) and PGE2 synthase. However, we failed to demonstrate the suppression of the activity of cyclooxygenase in PTSMC by dexamethasone. Since the elevation of [Ca2+]i is necessary for the contraction of airway smooth muscles, dexamethasone seems to reduce the contraction of airway smooth muscles by suppressing the rise in [Ca2+]i and the release of arachidonic acid metabolites. Reduced production of arachidonic acid metabolites may also contribute to improvement in the bronchial inflammation.

Mathematical modeling of fetal organ growth using the Rossavik growth model: IV. Lung

Growth of the fetal lung has been monitored by left lung area (LLA), right lung area (RLA), and total lung area (TLA) from 14 to 41 weeks menstrual age in 116 normal Japanese fetuses. Growth of the fetal heart and chest has also been monitored by heart area (HA) and chest area (CA), respectively. Growth curves for these parameters have been determined by using a Rossavik growth model [p = c(t)k+s(t)]. R2 values of 95.3%, 90.3%, 89.0%, 88.7%, and 92.1% were obtained for CA, HA, LLA, RLA, and TLA, respectively. Variability analysis indicated a progressive increase in variability with fetal age for these five parameters. Variability data were used with the growth curve models to determine standard curves for these parameters. These standard curves provide a superior means for evaluating the normal fetal lung growth in the fetus and for identifying pulmonary hypoplasia in utero.

[Imipenem/cilastatin sodium alone or combined with amikacin sulfate in respiratory infections]

In the present study, we used the envelope method to divide patients with respiratory infections into two groups: a monotherapy group given imipenem/cilastatin sodium (IPM/CS) and a combination therapy group given imipenem/cilastatin sodium plus amikacin sulfate (AMK). We then compared the clinical efficacy and safety between groups. 1. Safety was evaluated in 83 patients in the IPM/CS group and 88 in the IPM/CS + AMK group while clinical efficacy was evaluated in 77 and 80 patients in the respective groups. 2. The overall efficacy rate was 84.4% in the IPM/CS group. Among the main infections, the efficacy rates were 82.7% in 52 cases of pneumonia (including lung abscess), 100% in cases of infected bronchiectasis, 66.7% in six cases of secondary infection of chronic respiratory disease, and 100% in four cases of chronic bronchitis. The overall efficacy rate was 83.8% in the IPM/CS + AMK group. Among the main infections, the efficacy rates were 88.1% in 59 cases of pneumonia (including lung abscess), 83.3% in 12 cases of infected bronchiectasis, and 60.0% in five cases of secondary infection of chronic respiratory disease. No significant differences in efficacies were seen between groups. 3. In the IPM/CS group, the efficacy rates were 92.3% for patients without prior antibiotic therapy in the IPM/CS group and 68.0% for those with prior therapy; in the IPM/CS + AMK group, the respective rates were 83.7% and 83.9%. In the IPM/CS group, there was a significant difference in the responses of patients with and without prior antibiotic therapy (P < 0.05). 4. Side effects were observed in six patients in the IPM/CS group (7.2%) and two patients in the IPM/CS + AMK group (2.3%). Abnormal laboratory test results were noted in 5 patients in the IPM/CS group (6.0%) and in 10 in the IPM/CS + f1p4group (11.4%). There was no significant difference in the incidence of side effects between groups and no severe adverse reactions in either group. These results indicate that IPM/CS alone produces of good response in moderate to severe respiratory infections while IPM/CS combined with AMK is useful in intractable respiratory infections.

Syosaiko-to and saiboku-to (Chinese-Japanese herbal medicine) suppress the release of arachidonic acid metabolites from cultured porcine pulmonary artery endothelial cells

The influences of Syosaiko-to and Saiboku-to, traditional Chinese-Japanese medicines, on the arachidonic acid metabolism of porcine pulmonary artery endothelial cells (PPAEC) in culture were investigated. 6-keto-PGF1 alpha, a stable end product of prostacyclin, released by PPAEC during a 48 h incubation period with 1000 micrograms/ml of Syosaiko-to or Saiboku-to was significantly decreased. Analysis of the eicosanoid profile by high performance liquid chromatography revealed that both cyclooxygenase and lipoxygenase derivatives were released in smaller than usual proportions from PPAEC during 24 h incubation periods with 500 micrograms/ml of Syosaiko-to or Saiboku-to. Clinically, Syosaiko-to is used for chronic hepatitis and Saiboku-to is prescribed for bronchial asthma. The experimental findings could explain the anti-inflammatory effect of Syosaiko-to and Saiboku-to from the perspective of their influences on arachidonic acid metabolic activity associated with PPAEC.

Mechanical characteristics of air bearings for supporting a flexible optical disk

A disk-supporting mechanism for a high-capacity 90-mm (3.5-in) flexible optical-disk system is studied for low-cost recording media and small drives. The mechanical characteristics are analyzed by a simple calculation of dynamic air pressure generated by pocket thrust bearings and by measurements of disk vibrations. The flexible disk rotates stably, supported by two thrust air bearings fabricated in a plastic cartridge, with disk tilt less than 5 mrad and disk acceleration less than 5 m/s(2) The feasibility of this system is confirmed by write-erase operations at a 2-µm track pitch.

Mononuclear cell-conditioned medium enhances thrombin-stimulated PGI2 production by human umbilical vein endothelial cells in culture

We investigated the effect of blood mononuclear cell-conditioned medium on prostacyclin (PGI2) production by human umbilical vein endothelial cells in culture (HUVEC), and compared the potency of the conditioned medium in PGI2 production with that of various cytokines and lipopolysaccharide (LPS). HUVEC which had been preincubated with LPS, interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor (TNF alpha), or interferon-gamma (IFN-gamma) produced more PGI2 than control cells in response to thrombin. However, the HUVEC preincubated with the conditioned medium made with mononuclear cells with or without LPS (LPS-Mo-CM, Mo-CM) produced more PGI2 than those preincubated with LPS, IL-1 alpha, IL-1 beta, TNF alpha, or IFN-gamma. Although the concentrations or IL-1 beta and TNF alpha in the post-culture medium of HUVEC treated with LPS-Mo-CM were much higher than those with Mo-CM, LPS-Mo-CM which was made with 13,000/ml of mononuclear cells and 1 microgram/ml of LPS did not significantly augment the subsequent PGI2 production by HUVEC as compared with Mo-CM made with the same numbers of mononuclear cells. PGI2 production by Mo-CM-treated HUVEC still exceeded that of control cells, even when an excess amount of antibody to TNF alpha and/or IL-1 alpha was added to the Mo-CM. It is possible that Mo-CM contains unknown cytokines besides IL-1 and TNF which stimulate the HUVEC to produce PGI2.

PGI2 production and angiotensin converting enzyme activity in cultured porcine pulmonary artery endothelial cells treated with paraquat

The herbicide paraquat (PQ) is known to cause acute pulmonary edema at toxic dose and to induce morphologic changes in alveolar epithelial cells, even in the early phase of toxicity. However, whether the pulmonary vascular endothelial cells are specifically vulnerable to PQ is still controversial. To investigate the direct toxic and metabolic effects of PQ on pulmonary vascular endothelial cells, cultured porcine pulmonary artery endothelial cells (PPAEC) were evaluated. A dose of 10(-4) M of PQ inhibited the growth of endothelial cells. The thrombin- and bradykinin-stimulated production of prostacyclin (PGI2) by PPAEC was significantly enhanced, and the angiotensin converting enzyme (ACE) activity of cell lysate of PPAEC was significantly suppressed after incubation for 24 h with 10(-4) M PQ. No further enhancement of PGI2 production in response to thrombin after 48 h of incubation was demonstrated. These alterations in arachidonic acid metabolism and ACE activity did not result from the cytotoxicity of PQ, because the release of lactate dehydrogenase (LDH) into the culture medium increased only after 72 h incubation with PQ. Incubation for more than 48 h induced an obvious toxis effect on PPAEC.

Data reliability evaluation of flexible optical disk system using accelerated test of dust density

The data reliability of a 90-mm flexible optical disk system with a phase-change rewritable disk is studied through accelerated tests of dust density for fabrication of low-cost, reliable flexible optical disks. A simple dust generator composed of a small loud speaker creates an extremely dusty environment in a chamber, with a dust density several times higher than in a normal environment. These accelerated tests indicate that a flexible optical disk contained in a semisealed cartridge will show no change in the number of errors over several years in a normal environment.

Flexible optical disk system with a sample servo format

A high-capacity 90-mm flexible optical disk system with a phase-change rewritable disk is studied, aiming at low-cost recording media and small drives. The flexible disk rotates stably and is supported by two thrust air bearings fabricated in a plastic cartridge with a disk tilt of less than 5 mrad. A radial tracking-control precision of 0.2 microm is attained with a sample servo system by using photographically replicated square servo marks on the disk. The feasibility of this system is confirmed by write-erase operations in a 2-microm track pitch.

[Arachidonic acid metabolism and angiotensin converting enzyme activity by cultured porcine pulmonary artery endothelial cells are affected with paraquat]

Paraquat is a herbicide known to cause pulmonary edema in its acute toxic phase. Many investigators showed that paraquat induces morphological changes of alveolar epithelial cells even in its early phase. Controversy still exists, however, as to whether pulmonary vascular endothelial cells are also morphologically vulnerable to paraquat. To test the direct toxicity and metabolic changes of pulmonary vascular endothelial cells after paraquat addition, porcine pulmonary artery endothelial cells (PPAEC) were cultured. Thrombin- or bradykinin-stimulated PGI2 production was enhanced significantly, and the angiotensin converting enzyme (ACE) activity of cell lysate of PPAEC was significantly suppressed after a 24-hour incubation with 10(-4) M of paraquat. No further thrombin-induced enhancement of PGI2 production was noted after a 48-hour incubation. The alterations in arachidonic acid metabolism and ACE activity mentioned above did not result from cytotoxicity of paraquat because LDH release into culture medium was not increased during 72 hours of incubation with paraquat. Longer incubation more than 48 hours, in turn, induces obvious toxic effects on PPAEC.

[Clinical studies on ciprofloxacin in chronic respiratory tract infection]

Ciprofloxacin (CPFX), a new pyridone carboxylic acid, was administered orally to the patients with chronic respiratory tract infection and its clinical efficacy and safety were studied in a multicenter open trial. The results and summarized as follows. 1. The efficacy rate for the patients with acute exacerbation as 52.5% (21/40) in 2 week-treatment, and 75.0% (24/32) in 4 week-treatment. 2. The efficacy rate for the patients with chronic phase was 23.1% (6/26) in 2 week-treatment, and 26.9% (7/26) in 4 week-treatment, but acute exacerbation was not observed in any of the patients. 3. CPFX was administered to 6 patients over 60 days for the prophylaxis of acute exacerbation. Only 2 patients had acute exacerbation in 2 and 3 months after the start of the therapy, respectively. 4. Bacteriological eradication rate was high except P. aeruginosa, for which the eradication rate was about 20%. 5. Side effects were observed in 3 patients, and abnormal findings of laboratory tests were observed in 5 patients, though they were not severe. These results show that CPFX is a useful antimicrobial agent for the treatment of chronic respiratory tract infections.

Paraquat depresses the activity of angiotensin converting enzyme expressed by human umbilical vein endothelial cells in culture

The activity of angiotensin converting enzyme (ACE) in cell lysate of cultured human umbilical vein endothelial cells (HUVEC) after a 24-hour incubation with 10(-3) and 10(-4)M of paraquat (PQ) was decreased. However, LDH released into the culture medium of HUVEC during the 24-hour incubation with PQ was not increased. Many investigators show that the change in serum ACE activity reflects the impairment of vascular endothelial cells. We showed in this report that ACE was decreased even at an early stage of endothelial injury induced by PQ, when LDH release is not yet increased.