Incidence, diagnosis and pathophysiology of amniotic fluid embolism.

Amniotic fluid embolism (AFE) is a rare clinical entity, sometimes fatal. A review was conducted to describe the frequency, diagnosis and pathophysiology of AFE. The reported incidences ranged from 1.9 cases per 100,000 maternities (UK) to 6.1 per 100,000 maternities (Australia), which can vary considerably, depending on the period, region of study and the definition. Although the development of amniotic fluid-specific markers would have an impact on early diagnosis, definition of AFE based on these markers is not widely accepted. To date, immunological mechanisms, amniotic fluid-dependent anaphylactic reaction and complement activation, have been proposed as potential pathogenetic and pathophysiological mechanisms. Immune cell activation induced through complement activation may be associated with the mechanism that immediately initiates maternal death, only in susceptible individuals. This review will focus on advances in the field of AFE biology and discuss the prevalence, diagnosis and pathophysiology of AFE.

[Is emergency aortic root replacement combined with arch replacement safe?].

BACKGROUND: Aortic root replacement (ARR) combined with aortic arch replacement (AAR) is an invasive procedure even in elective cases. Nevertheless, such combined operations are often mandatory in acute type A aortic dissection. We examined whether emergency operation might have further incremental risks compared with elective surgery in this type of operations. METHODS: Forty-six cases of ARR combined with AAR were divided into 2 groups, the emergency (EM) group and the elective (EL) group. The EM group consisted of 10 cases of acute type A aortic dissection, whereas the EL group of 36:23 of chronic aortic dissection and 13 of true aneurysm. RESULTS: There were no statistical differences between the 2 groups in the durations of aortic crossclamp, selective cerebral perfusion and cardiopulmonary bypass. The incidences in the EM and EL groups were as follows:in-hospital death; 0 vs 3( 8%), respiratory failure; 4 (40%) vs 14 (39%), renal failure; 0 vs 6 (17%), IABP requirement; 1 (10%) vs 3 (8%), and cerebral infarction; 0 vs 1 (3%), respectively. CONCLUSION: Early surgical results of emergency ARR combined with AAR were almost equal to those in elective surgery.

Efficacy of perfusion cooling of the epidural space and cerebrospinal fluid drainage during repair of extent I and II thoracoabdominal aneurysm.

AIM: The aim of this study was to evaluate spinal cord injury and mortality resulting from repair of extent I and II thoracoabdominal aneurysm. The authors compared patients operated under mild hypothermia with or without epidural perfusion cooling (EPC) and cerebrospinal fluid drainage (CSFD). METHODS: From 1988 to 2007, 116 patients underwent replacement of the thoracoabdominal aorta; the procedure was performed in 38 patients with the aid of mild hypothermia alone (group A), and in 78 patients with the aid of EPC, mild hypothermia and CSFD (group B). Two catheters for epidural perfusion cooling were inserted in group B, in which one catheter was inserted into the epidural space to infuse chilled saline, and the other was inserted into the subdural space to drain the cerebrospinal fluid and to measure temperature and pressure. There were no significant differences in mean age, etiology of aortic disease, and aneurysm extent between the two groups. RESULTS: There were no significant differences in cardiopulmonary bypass time, the lowest nasopharyngeal temperature and operation time between the two study groups. The incidence of spinal cord injury in group A (16.2%) was significantly higher than in group B (3.8%, P=0.03). Hospital mortality in groups A and B was 10.5% and 2.6%, respectively (P=0.08). There was no significant difference in postoperative complications between the two study groups. CONCLUSION: The combination of EPC and CSFD was effective in lowering the incidence of postoperative spinal cord injury in the repair of extent I and II thoracoabdominal aortic aneurysm.

Human small Maf proteins form heterodimers with CNC family transcription factors and recognize the NF-E2 motif.

The transcription factor NF-E2, a heterodimeric protein complex composed of p45 and small Maf family proteins, is considered crucial for the regulation of erythroid gene expression and platelet formation. To facilitate the characterization of NF-E2 functions in human cells, we isolated cDNAs encoding two members of the small Maf family, MafK and MafG. The human mafK and mafG genes encode proteins of 156 and 162 amino acid residues, respectively, whose deduced amino acid sequences show approximately 95% identity to their respective chicken counterparts. Expression of mafK mRNA is high in heart, skeletal muscle and placenta, whereas mafG mRNA is abundant in skeletal muscle and is moderately expressed in heart and brain. Both are expressed in all hematopoietic cell lines, including those of erythroid and megakaryocytic lineages. In electrophoretic gel mobility shift assays binding to NF-E2 sites was found to depend on formation of homodimers or heterodimers with p45 and p45-related CNC family proteins. The results suggest that the small Maf family proteins function in human cells through interaction with various basic-leucine zipper-type transcription factors.

[Concomitant replacement of the complete aortic arch with coronary artery bypass grafting and ilio-femoral bypass grafting by means of selective cerebral and coronary perfusion technique].

A seventy-two-year-old male patient was diagnosed to have major three kinds of atherosclerotic disease including transverse aortic arch aneurysm, ischemic heart disease and stenosis of left external iliac artery. Complete graft replacement of aortic arch was performed concomitantly with the coronary arterial bypass grafting and iliofemoral bypass grafting under selective cerebral and coronary perfusion technique. In addition, the graft used for iliofemoral arterial reconstruction was tailored to have two branches, which facilitate the insertion of the inflow cannula for a bypass and the occlusion balloon catheter. His postoperative course was uneventful and was discharged under a satisfactory condition.

[Supra-annular mitral valve replacement for a patient with prosthetic valve endocarditis].

Supraanular mitral valve replacement with a 29 mm CarboMedics prosthetic valve was performed for a 58-year-old patient of prosthetic valve endocarditis. He has received mitral valve replacement 2 years ago, and was admitted because of high fever and severe heart failure diagnosed mitral regurgitation due to valve dehiscence. An annular abscess was observed and the new 29 mm CarboMedics prosthetic valve was sutured to the left atrial wall approximately 10 mm above the original annulus in order to secure the firm suturings for valve implantation and to left the infected annulus intact. The patient, however, underwent reoperation because of valve dehiscence from atrial wall 6 months after surgery. Infectious abscess at the native mitral annulau was observed to be completely cured, and a mitral prosthesis was implanted at the annulus. The patient is discharged under satisfactory condition.

[Aortobronchial fistula after replacement of descending thoracic aorta with ringed graft; report of a case].

A 79-year-old male patient complicated with aortobronchial fistula after replacement of descending thoracic aorta with ringed graft. He underwent replacement of the aortic arch using a four branched vascular graft and open stent grafting to replace the descending thoracic aorta after removing the ringed-graft through median sternotomy. This procedure is useful for patients as the left thoracotomy is risky and the distal anastomotic site of the descending thoracic aorta is too far to anastomose.

[Surgical treatment of thrombosed aortic dissection].

We have performed the graft replacement of descending thoracic aorta for 6 patients with aortic dissection having non-opacified false channel on their initial CT and aortography from April 1990 to January 1993. We report the findings obtained from preoperative CT and aortographic findings and from operation with these patients. We also report the microscopic study of aortic wall resected at operation. In all the six patients were found by CT and angiography performed at the admission non-opacified false channel. In one patient, a re-dissection occurred at the mid-descending aorta four weeks later and extended into the abdominal aorta. Intimal tears were found during operation both at distal to the left subclavian artery and at mid-descending aorta in this patient, and microscopically the outer media of aortic wall had been ruptured and the advential scarring were more conspicuous than usual. In the other 5 patients, the local opacification was gradually increased in size during the follow up period. The site of local opacification was at the distal to the left subclavian artery in 3 and at the mid-descending aorta in 2. The operation for these patients revealed the existence of intimal tear at the involved aorta but the false channel had been closed. Microscopically, the involved aorta formed pseudoaneurysm and false channel had been closed with the organized thrombus. From these findings we conclude that surgical treatment should be considered for the aortic dissection when re-dissection occurred or local opacification was increased in size during follow up period, even if initial CT and aortography showed non-opacified false channel.

[A case of visceral ischemia associated with acute type IIIb aortic dissection].

The case was a 61-year-old man who was transported to our hospital with complaining of severe chest and back pain of sudden onset and diagnosed as acute type IIIb aortic dissection. Inspite of intensive medical treatments, severe abdominal pain with abdominal distension and progressive metabolic acidosis appeared at around 11 hours after admission. Aortogram revealed obstruction of both superior and inferior mesenteric arteries suggesting visceral ischemia associated with acute type IIIb aortic dissection. Emergent operation consisting of bypass grafting for the superior and the inferior mesenteric arteries with saphenous vein, partial resection of small intestine, left hemicolectomy and construction of artificial anus was immediately carried out. The patient had no particular trouble after the operation and returned to the previous job.

[Clinical use of the multi-purpose circuit with a soft reservoir built in inflow side in replacement of the descending thoracic aorta].

The temporary bypass circuit under centrifugal pumping is generally applied for the assisted circulation of the operation for the aneurysm of descending aorta. The estimation of the bypass flow to the abdominal viscera, however, sometimes showed inadequate when excessive bleeding happened during operation. In order to keep constant flow to the lower body, we developed a new circuit, that has soft reservoir built in inflow side of the bypass line. In 8 subjects using this circuit, we studied the usefulness of the circuit and the choice of bypass route based on changes in the hemodynamics during bypass and operative complications in relation to bypass technique. During bypass, perfusion pressure to the lower body was 70-110 mmHg and flow was maintained at more than 21/min even if massive hemorrhage occurred. Comparing arterial bypass with LV bypass, the diastolic pressure in the upper limb was significantly depressed in arterial bypass with reading of 40-50 mmHg. Furthermore, in one case of arterial bypass involving the ascending aorta, false aneurysm is found in the site of cannulation. The rectal temperature dropped with the lapse of time from 35.5 +/- 0.8 degrees C to 33.5 +/- 0.4 degrees c in 120 min. These results indicate that multi-purpose circuit is capable of promptly supplying the circulating volume and is excellent means of providing adequate circulation to the lower body even if massive hemorrhage occurred. And LV bypass should be selected first, because arterial bypass has the hazard of depressing the diastolic pressure in the upper limb and involving complications associated with the insertion of cannula.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of hemothorax occurred two months after graft replacement of descending thoracic aorta with Hemashield arterial prosthesis].

A 70-year-old man performed graft replacement of descending thoracic aorta for chronic aortic dissection (DeBakey IIIb) with Hemashield arterial prosthesis. He also had coronary artery disease (LAD seg. 7.99% stenosis) and he had received PTCA prior to operation. He was administered anticoagulants such as Aspirin and Warfarin postoperatively. Two months after operation, he complained dyspnea and came back to our hospital. Chest X-ray showed left hemothorax. CT scan and aortogram could not revealed bleeding points such as pseudoanerysm at anastomosis site nor new dissection. He recovered after discontinued anticoagulants and drainage. If you need to use the anticoagulants after graft replacement with Hemashield, you should administer the anticoagulants about 14 days after operation. This is the first clinical report that hemothorax occurred two months after graft replacement with Hemashield.

Impaired megakaryopoiesis and behavioral defects in mafG-null mutant mice.

The small Maf proteins (MafG, MafK, and MafF), which serve as heterodimeric partner molecules of CNC family proteins for binding in vitro to MARE sites, have been implicated in the regulation of both transcription and chromatin structure, but there is no current evidence that the proteins fulfill these functions in vivo. To elucidate possible contributions of the small Maf proteins to gene regulation, we have ablated the mafG and mafK genes in mice by replacing their entire coding sequences with the Escherichia coli lacZ gene. mafG homozygous mutant animals exhibit impaired platelet formation accompanied by megakaryocyte proliferation, as well as behavioral abnormalities, whereas mafK-null mutant mice are phenotypically normal. Characterization of the mafG and mafK embryonic expression patterns show that their developmental programs are distinct and intersecting, but not entirely overlapping. These results provide direct evidence that the small Maf transcription factors are vital participants in embryonic development and cellular differentiation.

Effects of ultraviolet B irradiation on cell-cell interaction; implication of morphological changes and actin filaments in irradiated cells.

We studied the effects of ultraviolet B (UV-B) irradiation on cell-cell interactions using mouse lymphoma RMA cells and T cell hybridoma HTB-176.10. RMA cells act as stimulators by presenting H-2Kb surface antigens to HTB-176.10 cells, inducing IL-2 production in HTB-176.10 cells. Irradiating RMA cells with 1000J/m2 UV-B suppressed cell cluster formation between RMA and HTB-176.10 cells and reduced the level of IL-2 production in HTB-176.10 cells, although H-2Kb surface antigens of RMA cells were still expressed. Electron microscopic observations of irradiated RMA cells revealed that UV-B irradiation damaged cell structures, resulting in the disappearance of microvilli on the cell surface, destruction of mitochondria, vacuolation of cytoplasm and swelling of the perinuclear cisterna space. We found that these alterations were accompanied by polymerization of filamentous actin quantified by flow cytometry after NBD-phallacidin staining. Our results suggest that a target of UV-B-induced alterations is actin filaments, which support the cell morphology as the cytoskeleton, and that modification of filamentous actin inhibits interaction between RMA and HTB-176.10 cells. This underlying mechanism may account for the impaired interaction between antigen-presenting cells and T cells after transfusion with UV-B-irradiated allogeneic blood components.

Induction of murine intestinal and hepatic peroxiredoxin MSP23 by dietary butylated hydroxyanisole.

Feeding mice with 2(3)-t-butyl-4-hydroxyanisole (BHA) induces phase II detoxifying enzymes that inhibit the action of carcinogens. We have found that dietary BHA induces intestinal and hepatic MSP23 (also called peroxiredoxin I), a stress-inducible antioxidant, in a manner similar to the induction of glutathione S-transferases (GSTs). The levels of MSP23 in the proximal intestine and liver, estimated by immunoblotting, increased approximately 1.9- and 1.3-fold, respectively, in mice fed a diet containing 0.7% (w/w) BHA for 7 days. The level of MSP23 mRNA in these tissues also increased more than 2-fold after mice were fed BHA, suggesting that the induction of MSP23 is controlled at the transcription level. Immunostaining of the small intestine shows that MSP23 is expressed mainly in the columnar epithelial cells. The induction of MSP23 may be important to protect the cells and tissues against toxic electrophiles and reactive oxygen species.

Differential regulation of coproporphyrinogen oxidase gene between erythroid and nonerythroid cells.

Coproporphyrinogen oxidase (CPO) catalyzes the sixth step of the heme biosynthetic pathway. To assess the tissue-specific regulation of the CPO gene promoter, mouse genomic DNA clones for CPO were isolated. Structural analysis demonstrated that the mouse CPO gene spans approximately 11 kb and consists of seven exons, just like its human counterpart. Functional analysis of the promoter by transient transfection assays indicated that synergistic action between an SP-1-like element at -21/-12, a GATA site at -59/-54, and a novel regulatory element, CPRE (-GGACTACAG-) at -49/-41, is essential for the promoter activity in murine erythroleukemia (MEL) cells. In nonerythroid NIH3T3 cells, however, the GATA site is not required. Gel mobility shift assays demonstrated that specific DNA-protein complexes can be formed with each element, and that there are cell-specific differences in factors, which bind to the SP-1-like element between MEL and NIH3T3 cells. These results provide evidence for differential regulation of the promoter function of CPO gene between erythroid and nonerythroid cells.

Characterization of the murine mafF gene.

Small Maf proteins are obligatory heterodimeric partner molecules of mammalian Cap'n'Collar proteins that together control a wide variety of eukaryotic genes. Although both MafK and MafG are expressed in overlapping but distinct tissue distribution patterns during embryonic development, the physiological consequences of loss-of-function mutations in either gene are modest. This suggested that compensation by the third small Maf protein, MafF, might be a major reason for such mild phenotypes and that further analysis of MafF might therefore provide important insights for understanding small Maf regulatory function(s). We therefore cloned, mapped, transcriptionally and developmentally characterized, and finally disrupted the mafF gene. We show that murine mafF is transcriptionally regulated by three different promoters and is most abundantly expressed in the lung. The lacZ gene inserted into the mafF locus revealed prominent expression sites in the gut, lung, liver, outflow tract of the heart, cartilage, bone membrane, and skin but not in hematopoietic cells at any developmental stage. Homozygous mafF null mutant mice were born in a normal Mendelian ratio and displayed no obvious functional deficiencies, indicating that MafF activity may be dispensable even in tissues where the expression of other small Maf proteins is quite low.

Regulation of NF-E2 activity in erythroleukemia cell differentiation.

The erythroid transcription factor NF-E2 is an obligate heterodimer composed of two different subunits (p45 and p18), each containing a basic region-leucine zipper DNA binding domain, and it plays a critical role in erythroid differentiation as an enhancer-binding protein for expression of the beta-globin gene. We show here that dimethyl sulfoxide treatment of wild-type murine erythroleukemia cells, but not a mutant clone of dimethyl sulfoxide-resistant cells, increases NF-E2 activity significantly, which involves both up-regulation of DNA binding and transactivation activities. Both activities were reduced markedly by treatment of cells with 2-aminopurine but not by genistein. Activation of the Ras-Raf-MAP kinase signaling cascade increased NF-E2 activity significantly, but this was suppressed when MafK was overexpressed. Domain analysis revealed an activation domain in the NH2-terminal region of p45 and a suppression domain in the basic region-leucine zipper of MafK. These findings indicate that induction of NF-E2 activity is essential for erythroid differentiation of murine erythroleukemia cells, and serine/threonine phosphorylation may be involved in this process. In addition, they also suggest that a MafK homodimer can suppress transcription, not only by competition for the DNA binding site, but also by direct inhibition of transcription. Hence, MafK may function as an active transcription repressor.

[Advantages of combined antegrade/retrograde GIK cardioplegia for coronary artery bypass surgery].

We evaluated the advantages of combined antegrade and retrograde GIK cardioplegia in 65 patients undergoing CABG. Thirty seven patients were administered antegrade cardioplegia (Group A), whereas 28 patients were administered combined antegrade and retrograde cardioplegia (Group C). Enzyme release and hemodynamic data were obtained before the onset of CPB and at 1, 3, 6, 9, 12 and 24 hours after operation. Both groups were similar in age and incidence of diabetes, previous MI, PTCA, severity of coronary artery disease and emergent operation. In group A, antegrade cardioplegia produced poor anterior septal cooling in 17 patients (45%). To ensure adequate myocardial protection in these cases 9, patients were anastomosed saphenous vein graft first to LAD instead of IMA and perfused cardioplegic solution through the grafts. In group C, although adequate anterior septal cooling also could not be obtained with antegrade cardioplegia in 16 patients (57%), after retrograde cardioplegia, anterior septal temperature fell below 10 degrees C. The use of IMA graft was more practiced in group C. (79% in group C versus 32% in group A, p < 0.05) Enzyme release (CPK-MB, %CPK-MB, LDH) and hemodynamic data (CI, LVSWI, RVSWI, RVEF, RVEDVI) were similar in both group. Furthermore, no significant difference were noted in the incidence of post-operative LOS, PMI and ventricular arrhythmia. We concluded that the use of combined antegrade and retrograde cardioplegia is more effective than antegrade cardioplegia, because of adequate anterior septal cooling, and it will allow patients with severe and extent coronary artery disease to undergo safe IMA grafting.