Leaf senescence under various gravity conditions: relevance to the dynamics of plant hormones.

Effects of simulated microgravity and hypergravity on the senescence of oat leaf segments excised from the primary leaves of 8-d-old green seedlings were studied using a 3-dimensional (D) clinostat as a simulator of weightlessness and a centrifuge, respectively. During the incubation with water under 1-g conditions at 25 degrees C in the dark, the loss of chlorophyll of the segments was found dramatically immediately after leaf excision, and leaf color completely turned to yellow after 3-d to 4-d incubation. In this case kinetin (10 micromolar) was effective in retarding senescence. The application of simulated microgravity conditions on a 3-D clinostat enhanced chlorophyll loss in the presence or absence of kinetin. The loss of chlorophyll was also enhanced by hypergravity conditions (ca. 8 to 16 g), but the effect was smaller than that of simulated microgravity conditions on the clinostat. Jasmonates (JAs) and abscisic acid (ABA) promoted senescence under simulated microgravity conditions on the clinostat as well as under 1-g conditions. After 2-d incubation with water or 5-d incubation with kinetin, the endogenous levels of JAs and ABA of the segments kept under simulated microgravity conditions on the clinostat remained higher than those kept under 1-g conditions. These findings suggest that physiological processes of leaf senescence and the dynamics of endogenous plant hormone levels are substantially affected by gravity.

Growth and development in higher plants under simulated microgravity conditions on a 3-dimensional clinostat.

Growth and development of etiolated pea (Pisum sativum L. cv. Alaska) and maize (Zea mays L. cv. Golden Cross Bantam) seedlings grown under simulated microgravity conditions were intensively studied using a 3-dimensional clinostat as a simulator of weightlessness. Epicotyls of etiolated pea seedlings grown on the clinostat were the most oriented toward the direction far from cotyledons. Mesocotyls of etiolated maize seedlings grew at random and coleoptiles curved slightly during clinostat rotation. Clinostat rotation promoted the emergence of the 3rd internodes in etiolated pea seedlings, while it significantly inhibited the growth of the 1st internodes. In maize seedlings, the growth of coleoptiles was little affected by clinostat rotation, but that of mesocotyls was suppressed, and therefore, the emergence of the leaf out of coleoptile was promoted. Clinostat rotation reduced the osmotic concentration in the 1st internodes of pea seedlings, although it has little effect on the 2nd and the 3rd internodes. Clinostat rotation also reduced the osmotic concentrations in both coleoptiles and mesocotyls of maize seedlings. Cell-wall extensibilities of the 1st and the 3rd internodes of pea seedlings grown on the clinostat were significantly lower and higher as compared with those on 1 g conditions, respectively. Cell-wall extensibility of mesocotyls in seedlings grown on the clinostat also decreased. Changes in cell wall properties seem to be well correlated to the growth of each organ in pea and maize seedlings. These results suggest that the growth and development of plants is controlled under gravity on earth, and that the growth responses of higher plants to microgravity conditions are regulated by both cell-wall mechanical properties and osmotic properties of stem cells.

[Traumatic cardiac tamponade due to the nail stabbing].

A 45-year-old man was admitted to our hospital complaining of mild chest pain. The stab wound on the chest was very small and the nail had been completely buried under the skin. Emergency operation was mandatory for cardiac tamponade by the nail stabbing. Contused right ventricular wall was repaired using Teflon felt under cardiopulmonary bypass. It was important to have a suspicion as cardiac tamponade, when the patient showed uncertain hypotension.

Surgical repair of a solitary deep femoral arterial aneurysm: report of two cases.

We report herein two cases of a solitary deep femoral arterial aneurysm that were successfully treated by aneurysmectomy and ligation of the deep femoral artery. The patients were a 69-year-old man and a 73-year-old man, both of whom presented with localized pain and a pulsatile mass in the femoral area showing rapid enlargement. Ultrasonography and arteriography confirmed the diagnosis and revealed no evidence of aneurysm or occlusive disease in the other arteries. Aneurysmectomy and ligation of the deep femoral artery were performed, and no ischemic symptoms or thrombus developed postoperatively in either patient. Preoperative arteriography is essential to delineate not only the state of the aneurysm, but also that of the distal arterial tree. An emergency operation is also mandatory due to the rapid enlargement of this type of aneurysm, even if rupture occurs.

STS-95 space experiment for plant growth and development, and auxin polar transport.

The principal objective of the space experiment, BRIC-AUX on STS-95, was the integrated analysis of the growth and development of etiolated pea and maize seedlings in space, and the effect of microgravity conditions in space on auxin polar transport in the segments. Microgravity conditions in space strongly affected the growth and development of etiolated pea and maize seedlings. Etiolated pea and maize seedlings were leaned and curved during space flight, respectively. Finally the growth inhibition of these seedlings was also observed. Roots of some pea seedlings grew toward the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles which were germinated and grown under microgravity conditions in space were significantly low. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and extremely promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

Growth and development, and auxin polar transport in higher plants under microgravity conditions in space: BRIC-AUX on STS-95 space experiment.

The principal objectives of the space experiment, BRIC-AUX on STS 95, were the integrated analysis of the growth and development of etiolated pea and maize seedlings in space and a study of the effects of microgravity conditions in space on auxin polar transport in these segments. Microgravity significantly affected the growth and development of etiolated pea and maize seedlings. Epicotyls of etiolated pea seedlings were the most oriented toward about 40 to 60 degrees from the vertical. Mesocotyls of etiolated maize seedlings were curved at random during space flight but coleoptiles were almost straight. Finally the growth inhibition of these seedlings in space was also observed. Roots of some pea seedlings grew toward to the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles, which were germinated and grown under microgravity conditions in space, were significantly low as compared with those grown on the ground of the earth. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

Pedicle transposition of the greater omentum for sternal osteomyelitis and mediastinitis after cardiac operation.

Three patients underwent pedicle transposition of the greater omentum for sternal osteomyelitis and mediastinitis after cardiac operation. These patients were previously operated on with coronary artery bypass grafting, aortic valve replacement and redo Fontan operation in each. This procedure was carried out on 4, 6, 8, and 14th postoperative day. The complications cured within about one month after the procedure in all cases. It is suggested that this maneuver is effective for obtaining healing osteomyelitis and mediastinitis following cardiac operation.

[Acute ventricular septal perforation in a patient with autoimmune hemolytic anemia].

A 71-year-old woman with autoimmune hemolytic anemia underwent an emergency endocardial patch repair for ventricular septal perforation after acute myocardial infarction. Use of washed red blood cells was effective in averting hemolytic crisis throughout perioperative period. In spite of improvement of her hemodynamics, liver dysfunction which had been present preoperatively deteriorated after the operation. Finally she died of hepatic failure on the 21st postoperative day. Deterioration of liver function could not be associated with autoimmune hemolytic anemia. To date, little information is available concerning the influence of cardiopulmonary bypass on hemolysis in patients with autoimmune hemolytic anemia. Therefore, prudent management and use of washed red blood cells transfusion would prevent hemolytic aggravation even in open heart surgery.

[A surgical case of aortic valve stenosis associated with systemic lupus erythematosus].

A 46-year-old woman was hospitalized for aortic valve stenosis (AS) associated with systemic lupus erythematosus (SLE) on April 12, 1996. She had a syncopal episode six months before admission. She was found to have thrombocytopenia, and was diagnosed with SLE by further examination. Irregular genital bleeding was also seen on admission while her SLE was being controlled with steroid therapy. Aortic valve replacement was performed after the steroids had been reduced to avoid excessive bleeding. The aortic valve was the bicuspid with raphe. There was much calcification on the cusps and the annulus, but there were no degenerative changes. The postoperative course was uneventful, and her SLE has been in remission two years after the operation. The management of steroid therapy for SLE patients complicated with cardiovascular disease is discussed.

[Retrieval of intravascular catheter fragment remaining for 15 years--a case report].

A 66-year-old woman was operated on aortic valve replacement, mitral valve replacement, and tricuspid annuloplasty. Retrieval of remaining Swan-Ganz Thermodilution catheter in the superior vena cava and the right atrium for 15 years was also made. Fortunately, contamination and embolism have not occurred for 15 years. Extracted catheter showed to be stiff due to the degradation. It was suggested that the cause of remaining was the thread for closing the left atrium on the previous operation. The explanation to patient and one's recognition are most important. We recommend that retrieval of remaining catheter for a long time and/or after open heart surgery should be made under extracorporeal circulation because that remaining catheter may be involved with the intima, and preventing from bleeding.

Right atrial mural thrombus associated with pericarditis.

A 33-year-old man was hospitalized with right heart failure. He was diagnosed as having right atrial mural thrombus complicated with pericarditis on echocardiography, thoracic computed tomography, and cardiac catheterization. Pericardiectomy and thrombectomy with a partial resection of the right atrial wall were performed under extracorporeal circulation. It was suggested that the cause of right atrial thrombus was congestion, atrial fibrillation, and pericarditis. The cause of pericarditis could not be determined by pathologic examination and laboratory data. Surgical treatment should be performed as soon as possible to prevent pulmonary embolism.

[Perforation and localized dissection of the left common iliac artery during the modified Bentall procedure: a case report].

We performed the modified Bentall procedure for annuloaortic ectasia in a 41-year-old man with Marfan's syndrome. Approximately 15 minutes after initiation of cardiopulmonary bypass with an arterial delivery via the left common femoral artery, perfusion volume gradually decreased and the abdomen of the patient was distended. Retrograde dissection was strongly suggested. Perforation and localized dissection of the left common iliac artery were recognized. Following repair of the lesion, the modified Bentall operation was carried out. Postoperative course was uneventful. The patient has been well for 22 months after the operation.

Prolongation of liposome circulation time by various derivatives of polyethyleneglycols.

New lipid derivatives of polyethyleneglycol (PEG) have been synthesized and tested for the ability to allow liposomes to evade uptake by the reticuloendothelial system (RES) and to prolong the circulation time of liposomes in mice. Liposomes were prepared from distearoylphosphatidylcholine (DSPC) and cholesterol (CH) (1:1, m/m) containing 6 mol% of various PEG-derivatives. The activity of the CH derivative of PEG (CH-PEG) in prolonging the circulation time of liposomes was proportional to the average molecular weight of PEG, i.e., 4800 > 2600 > 1700 > 800. alpha-Methoxy-omega-(1,2-dioctadecenoyloxy glyceryl)polyoxyethylene (DO-PEG) 1000 and alpha-methoxy-omega-(1,2-ditetradecenoyloxy glyceryl) polyoxyethylene (DT-PEG) 1000, in which PEG is directly linked to glycerol, prolonged the circulation time as effectively as distearoylphosphatidyl-N-(methoxy polyoxyethylene succinyl)-ethanolamine (DSPE-PEG). PEG-derivatives with a functional group at the PEG terminal, such as distearoyl-phosphatidyl-N-(3-carboxypropionyl polyoxyethylene succinyl)ethanolamine (DSPE-PEG-COOH) and alpha-(dipalmitoylphosphatidyl)-omega-hydroxypolyoxyethylene (DPP-PEG-OH), effectively prolonged the circulation time of liposomes. Incorporation of PEG-derivatives did not change membrane fluidity even after treatment with serum. Furthermore, incorporation of PEG-derivatives into liposomes decreased uptake by J774 cells, a murine macrophage-like cell line, in vitro. The newly synthesized PEG-derivatives seem to prevent or reduce the interactions of liposomes with serum protein and macrophages, resulting in enhanced stability and a prolonged circulation time.

[Re-do Fontan operation--a case report].

A 32-year-old woman developed heart failure. She had received Glenn operation 26 years ago and Fontan operation using valved conduit (Björk-Shiley: 21 mm) seven years ago for tricuspid atresia type 1b. She underwent extirpation of the struck prosthetic valve. Neither graft stenosis nor pressure gradient between the right atrium and the pulmonary artery were observed on postoperative right arteriography. Sternotomy on redo Fontan operation should be carefully performed for preventing breaking down the implanted valved conduit. Though the prosthetic valve was not necessary on redo Fontan operation, anticoagulation after operation should be done.

[Surgical results of valve replacement with porcine bioprostheses].

We evaluated the 80 cases of porcine valve replacement, accomplished between April 1975 and December 1980. There were 48 males and 32 females aged between 16 and 60 years old with a mean of 37.4 +/- 11.4. Ten patients underwent aortic valve replacement (AVR), 63 mitral valve (MVR), and 7 AVR plus MVR. Twenty-seven Hancock valves (H) were implanted in aortic (3) and mitral (24) position and 61 Carpentier-Edwards valves (CE) were used in aortic (14), mitral (46), and tricuspid (1) position. The mean duration of follow-up was 9.3 years (0.2-19.2 years) and cumulative follow-up was 747.2 patient years (py). The late mortality was 3.3%/py (25 patients). Actuarial survival rates for all patients at 10 and 15 years were 67%, and 49% respectively. The linearized rates (LR) of structural valve deterioration (SVD) was 7.0%/py. The freedom from SVD for all patients at 10, and 15 years were 47.1%, and 12.4% respectively. There were no differences of free rates of SVD between H and CE. between valve sites implated, and among age at operation. The incidence of occurrence of SVD was gradually increased 6 years after operation. The LR of thromboembolism (TE), anticoagulant-related hemorrhage (ACH), prosthetic valve endocarditis (PVE), nonfunctional valve dysfunction (NVD), and reoperation (RO) were 0.7%/py, 0.1%/py, 0.3%/py, 0.1%/py and 7.4%/py, respectively. The freedom from TE, ACH, PVE, NVD, and RO for all patients at 15 years were 91.3%, 98.1%, 95.6%, 80%, and 6.5%, respectively. The surgical results of glutaraldehyde-preserved porcine bioprostheses was excellent during the first 5 years after operation. A high incidence of SVD has been occurred thereafter. According the indication for valve replacement with bioprotheses is now strictly limited for elderly, child bearing female case, contraindition for therapy of anticoagulants, and some social condition.

[Use of the omentum for infected sternal dehiscence after aortic valve replacement--a case report].

A 68-year-old man had prosthetic valve replacement for aortic stenosis. Unfortunately, sternal dehiscence with osteomyelitis occurred on the fifth postoperative day. Implantation of the pedicled omentum to the wound was carried out three days later. The result was excellent. This is the worthy method to try to such wound of infected sternum with dehiscence. From the point of view of anatomy and physiology, the omentum has a great benefit to repair the infected space and promote the wound healing process.

Targetability of novel immunoliposomes modified with amphipathic poly(ethylene glycol)s conjugated at their distal terminals to monoclonal antibodies.

Distearoyl-N-(3-carboxypropionoyl poly(ethylene glycol) succinyl)phosphatidylethanolamine (DSPE-PEG-COOH) was newly synthesized and used to prepare novel immunoliposomes carrying monoclonal antibodies at the distal ends of the PEG chains (Type C). Liposomes were prepared from egg phosphatidylcholine (ePC) and cholesterol (CH) (2;1, m/m) containing 6 mol% of DSPE-PEG-COOH, and a monoclonal IgG antibody, 34A, which is highly specific to pulmonary endothelial cells, was conjugated to the carboxyl groups of DSPE-PEG-COOH to give various amounts of antibody molecules per liposome. Other immunoliposomes with PEG coating (Type B) or without PEG coating (an earlier type of immunoliposome, Type A) were prepared for comparison. The average molecular weight of PEG in Type B or C immunoliposomes was 2000. Type B and Type C liposomes without antibodies showed prolonged circulation time and reduced reticulo-endothelial system (RES) uptake owing to the presence of PEG. These three different types of 34A-immunoliposomes with 30-35 antibody molecules per vesicle were injected into mice to test the immunotargetability to the lung. The efficiency of lung binding of 34A-Type B was one-half of that of 34A-Type A, though a large amount of 34A-Type B remained in the blood circulation for a long time, suggesting that the steric hindrance of PEG chains reduced not only the immunospecific antibody-antigen binding, but also the RES uptake. The degree of lung binding of 34A-Type C was about 1.3-fold higher than that of 34A-Type A, indicating that recognition by the antibodies attached to the PEG terminal was not sterically hindered and that the free PEG (i.e., that not carrying antibody) was effective in increasing the blood concentration of immunoliposomes by enabling them to evade RES uptake. The latter phenomenon was confirmed by using nonspecific antibody-Type C immunoliposomes (14-Type C), which showed a high blood level for a long time. Our approach provides a simple means of conjugating antibodies directly to the distal end of PEG which is already bound to the liposome membrane, and should contribute to the development of superior targetable drug delivery vehicles for use in diagnostics and therapy.

[Nonsurgical retrieval of intravascular catheter fragments].

The incidence of catheter fragment induced by iatrogenic accident has been increasing because of frequent use of intravenous catheters and catheterization in daily practice. Migrated intravascular fragments from broken catheters were retrieved transcutaneously in four cases. All fragments were removed safely using biotome, multipurpose grasping forceps and basket catheter. But in a case which the fragment was lodged in the pulmonary artery, retrieval was not easy and it took many times. Fragments lodged in the right ventricle and in the pulmonary artery cause many complications including deaths. So broken fragments should be removed as soon as possible, before it migrated to there.

Enhanced delivery and antitumor activity of doxorubicin using long-circulating thermosensitive liposomes containing amphipathic polyethylene glycol in combination with local hyperthermia.

Enhanced delivery of doxorubicin (DXR) to a solid tumor subjected to local hyperthermia was achieved by using long-circulating, thermosensitive liposomes (TSL) composed of dipalmitoyl phosphatidylcholine (DPPC)/distearoyl phosphatidylcholine (DSPC) (9:1, m/m) and 3 mol% amphipathic polyethylene glycol (PEG) in colon 26-bearing mice. Inclusion of 3 mol% of distearoyl phosphatidylethanolamine derivatives of PEG (DSPE-PEG, amphipathic PEG) with a mean molecular weight of 1000 or 5000 in DPPC/DSPC liposomes resulted in decreased reticuloendothelial system (RES) uptake and a concomitant prolongation of circulation time, affording sustained increased blood levels of the liposomes. Concomitantly, DXR levels in blood were also kept high over a long period. The presence of amphipathic PEG did not interfere with the encapsulation of DXR by the pH gradient method (> 90% trapping efficiency) or with the temperature-dependent drug release from the liposomes. The optimal size of these liposomes was 180-200 nm in mean diameter for thermosensitive drug release and prolonged circulation time. The DXR levels in the tumor after injection of long-circulating TSL (DXR-PEG1000TSL or DXR-PEG5000TSL, at a dose of 5 mg DXR/kg) with local hyperthermia were much higher than after treatment with DXR-TSL lacking PEG or with free DXR, reaching 7.0-8.5 DXR micrograms/g tumor (approximately 2 times or 6 times higher than that of DXR-TSL or free DXR, respectively). Furthermore, the combination of DXR-PEGTSL and hyperthermia effectively retarded tumor growth and increased survival time.(ABSTRACT TRUNCATED AT 250 WORDS)