Generation of interspecies limited chimeric nephrons using a conditional nephron progenitor cell replacement system

Animal fetuses and embryos may have applications in the generation of human organs. Progenitor cells may be an appropriate cell source for regenerative organs because of their safety and availability. However, regenerative organs derived from exogenous lineage progenitors in developing animal fetuses have not yet been obtained. Here, we established a combination system through which donor cells could be precisely injected into the nephrogenic zone and native nephron progenitor cells (NPCs) could be eliminated in a time- and tissue-specific manner. We successfully achieved removal of Six2+ NPCs within the nephrogenic niche and complete replacement of transplanted NPCs with donor cells. These NPCs developed into mature glomeruli and renal tubules, and blood flow was observed following transplantation in vivo. Furthermore, this artificial nephron could be obtained using NPCs from different species. Thus, this technique enables in vivo differentiation from progenitor cells into nephrons, providing insights into nephrogenesis and organ regeneration.

The transplantation of tissue-specific progenitor cells may be an approach in organ regeneration. Here the authors show that the nephron progenitor population of a developing mouse kidney, when ablated, can be replaced by exogenously supplied rat nephron progenitors, generating interspecies nephrons.

Comparative study of the physiological properties of collagen, gelatin and collagen hydrolysate as cosmetic materials

The cell biological properties of collagen, gelatin and collagen hydrolysate (<15 000 Da) were studied using murine keratinocytes. Keratinocyte culture experiments demonstrated that only collagen had significant effects on cell attachment and proliferation, but the results of cells cultured on gelatin and collagen hydrolysate showed the rates of adhesion and proliferation were similar to those of cells cultured on plastic as a control. It is concluded that collagen has better physiological effects than those of gelatin and collagen hydrolysate as skin-care cosmetic materials.

Perioperative outcomes for elective open abdominal aortic aneurysm repair since the adoption of endovascular grafting procedures

OBJECTIVES

The objective of this study was to evaluate and compare our perioperative outcomes for open abdominal aortic aneurysm (AAA) between the pre-endovascular aneurysm repair (pre-EVAR) and EVAR eras and to analyse whether the AAA that was excluded from EVAR could affect the perioperative outcome.

MATERIALS AND METHODS

The Kurume University Hospital vascular registry was reviewed to identify all patients undergoing an elective open AAA repair from January 2004 through November 2006 (pre-EVAR era, n = 99) and from December 2006 through June 2010 (EVAR era, n = 125). The early clinical outcomes between the two groups were compared.

RESULTS

In the EVAR era, the proportion of EVAR in all elective AAA repairs was 43.4%. The EVAR era had a significantly higher proportion of very elderly patients over 80 years of age (23.2% vs. 11.1%, P = 0.0391). The morbidity rates were similar between the two groups (22.3% vs. 24,8%) and the mortality rate was 0% for both.

CONCLUSION

Despite the increased complexity of OAR in the EVAR era, we believe that OAR remains a valid procedure for AAA repair.

Ability of anaerobic microorganisms to associate with iodine: 125I tracer experiments using laboratory strains and enriched microbial communities from subsurface formation water

Iodine-129 ((129)I) is a fission product with a half-life of 15.7 million years. Because of its long half-life, high mobility, and high affinity to the human body, (129)I is considered as one of the most problematic radionuclides in nuclear waste disposals in deep geological formation. In this study, 16 strains of anaerobic microorganisms, including nitrate-reducing bacteria, iron-reducing bacteria, sulfate-reducing bacteria, and methanogens, were cultured anaerobically with a radioiodine tracer ((125)I) to determine whether they possess the ability to associate with iodine. We evaluated it by association efficiency, that was determined by measuring the decrease in (125)I activity in the culture supernatant. It was found that the efficiency of about half of the strains was below detection limit (1.0%), and that of the remaining strains varied from 1.0% to 6.3%, although it was not statistically significant. Similar experiments were conducted by using anaerobic microbial communities inhabiting the iodine-rich subsurface formation water collected from the Minami-kanto gas field in Japan. The specific uptake of iodine by the microbial communities was estimated to be 0.71-2.0 microg g(-1) dry weight of biomass, indicating that the association ability was, if present, very limited. These results suggest that anaerobic microorganisms, in contrast with aerobic microorganisms, neither enhance nor repress the mobility of (129)I, in the case of discharge of this radionuclide from disposal facilities into the surrounding environment.

Association between expression of vascular endothelial growth factor C, chemokine receptor CXCR4 and lymph node metastasis in colorectal cancer

OBJECTIVES

Lymph node metastasis is one of the determining factors of a poor prognosis for colorectal cancer. Recent studies have reported that cancer cells can promote lymphangiogenesis and that chemokine receptors expressed by cancer cells might play a role in metastasis. In this study, we examined the correlation between the expression of vascular endothelial growth factor (VEGF) C, the chemokine receptor CXCR4 and lymph node metastasis in colorectal cancer.

METHODS

One hundred and sixty-one consecutive patients who underwent resection at our department were studied. Lymph node metastasis was observed in 69 cases (43%) and lymphatic involvement was present in 105 cases (65%). Immunohistochemical staining was performed using antibodies for VEGF-C and CXCR4. Moreover, lymphatic vessel density (LVD) was evaluated within the tumor by immunostaining with a D2-40 antibody.

RESULTS

VEGF-C expression was found in 81 cases (50%) and CXCR4 expression in 87 cases (54%). Regarding the correlation between nodal metastasis and the expression of CXCR4 and VEGF-C, the incidence of nodal metastasis was significantly (p < 0.01) higher in patients with CXCR4-positive tumors than in those with CXCR4-negative tumors. In addition, a significant correlation was observed between CXCR4 and VEGF-C expression and lymphatic invasion (p < 0.01). LVD was significantly higher in VEGF-C-positive tumors compared with VEGF-C-negative tumors. However, there was no significant correlation between LVD and CXCR4 expression. Using multivariate analysis, VEGF-C, CXCR4, lymphatic invasion and wall invasion were found to be independent risk factors for lymph node metastasis.

CONCLUSIONS

This study suggests that although the mechanism that promoted lymph node metastasis was different between VEGF-C and CXCR4, both VEGF-C and CXCR4 contributed to lymphatic involvement and nodal metastasis in colorectal cancer.

Assessment of muscle blood flow volume in elderly poststroke hemiplegic patients using near-infrared spectroscopy

This study assessed the changes in blood flow volume in elderly hemiplegic patients before and after rehabilitation training. Total hemoglobin accumulation (blood flow volume) was measured using near-infrared spectroscopy (NIRS) in both the affected and unaffected gastrocnemius muscles before and after walking. In the gastrocnemius on the affected side, the blood flow volume was larger during the recovery period than during the rest period, and the blood flow volume did not decrease during the recovery period after the subjects walked a corridor. By contrast, the blood flow volume recovered faster on the unaffected side than on the affected side. After the subjects walked the stairs, the blood flow volume increased in the gastrocnemius muscles on both sides. These results suggested that the level of training involved in walking a corridor was too light for the unaffected side, although it was effective for the affected side. In our subjects, walking the stairs was effective rehabilitation training for both the unaffected and affected sides. Our results suggested that NIRS was an objective tool useful for planning rehabilitation training.

N-methyl-D-aspartate receptors play important roles in acquisition and expression of the eyeblink conditioned response in glutamate receptor subunit delta2 mutant mice

Classical eyeblink conditioning has been known to depend critically on the cerebellum. Apparently consistent with this, glutamate receptor subunit delta2 null mutant mice, which have serious morphological and functional deficiencies in the cerebellar cortex, are severely impaired in delay paradigm. However, these mutant mice successfully learn in trace paradigm, even in '0-trace paradigm,' in which the unconditioned stimulus starts just after the conditioned stimulus terminates. Our previous studies revealed that the hippocampus and the muscarinic acetylcholine receptors play crucial roles in 0-trace paradigm in glutamate receptor subunit delta2 null mutant mice unlike in wild-type mice, suggesting a large contribution of the forebrain to 0-trace conditioning in this type of mutant mice. In the present study, we investigated the role of N-methyl-D-aspartate receptors in 0-trace eyeblink conditioning in glutamate receptor subunit delta2 null mutant mice. Mice were injected intraperitoneally with the noncompetitive N-methyl-d-aspartate receptor antagonist (+)MK-801 (0.1mg/kg) or saline, and conditioned with 350-ms tone conditioned stimulus followed by 100-ms periorbital shock unconditioned stimulus. Glutamate receptor subunit delta2 null mutant mice that received (+)MK-801 injection exhibited a severe impairment in acquisition of the conditioned response, compared with the saline-injected glutamate receptor subunit delta2 null mutant mice. In contrast, wild-type mice were not impaired in acquisition of 0-trace conditioned response by (+)MK-801 injection. After the injection solution was changed from (+)MK-801 to saline, glutamate receptor subunit delta2 null mutant mice showed a rapid and partial recovery of performance of the conditioned response. On the other hand, when the injection solution was changed from saline to (+)MK-801, glutamate receptor subunit delta2 null mutant mice showed a marked impairment in expression of the pre-acquired conditioned response, whereas impairment of the expression was small in wild-type mice. Injection of (+)MK-801 had no significant effects on spontaneous eyeblink frequency or startle eyeblink frequency to the tone conditioned stimulus in either glutamate receptor subunit delta2 null mutant mice or wild-type mice. These results suggest that N-methyl-D-aspartate receptors play critical roles both in acquisition and expression of the conditioned response in 0-trace eyeblink conditioning in glutamate receptor subunit delta2 null mutant mice.

Damage of yeast cells induced by pulsed light irradiation

DNA damage, such as formation of single strand breaks and pyrimidine dimers was induced in yeast cells after irradiation by pulsed light, which were essentially the same as observed with continuous ultraviolet (UV) light. The UV-induced DNA damage is slightly higher than seen with pulsed light. However, increased concentration of eluted protein and structural change in the irradiated yeast cells were observed only in the case of pulsed light. A difference in the inactivation effect between pulsed light and UV light was found and this suggested cell membrane damage induced by pulsed light irradiation. It is proposed that pulsed light can be used as an effective sterilizing method for the yeast Saccharomyces cerevisiae.

Hepatoblastoma associated with Beckwith-Wiedemann syndrome and hemihypertrophy

Both Beckwith-Wiedemann syndrome (BWS) and hemihypertrophy (HH) have been recognized to be overgrowth syndromes associated with an increased risk of cancer. We report an infant with hepatoblastoma associated with both BWS and HH in whom high serum alpha-fetoprotein (AFP) levels persisted even after complete tumor resection with no tumor recurrence. This phenomenon might be partly due to the nature of the proliferative disease. It is important to recognize that in some infants with BWS prolonged high serum AFP levels mimic the existence of a tumor, and that treatment should be based not only on AFP measurement, but also on repeated radiologic imaging.

Surgery for primary cardiac tumors. Clinical experience and surgical results in 60 patients

BACKGROUND

We reviewed our clinical experience with primary cardiac tumors, attempting to clarify the surgical management of these rare entities.

METHODS

Between October 1978 and November 1999, we experienced 60 surgical cases of primary cardiac tumors. There were 23 male and 37 female patients (age range, 7 months to 84 years). Tumors included the following 3 groups: myxomas (n=49), nonmyxoma benign tumors (n=3), and malignant tumors (n=8). We reviewed the presenting symptoms, diagnostic data, anatomical findings, and surgical techniques, and evaluated the surgical RESULTS. Late follow-up was 95% complete (mean follow-up, 7.7+/-7.1 years).

RESULTS

Tumors produced obstructive, embolic, and/or constitutional symptoms in most cases. Generally, echocardiography alone gave sufficient information for operation. Full-thickness excision was performed in 42 patients with myxoma. Complete excision was achieved in all of the nonmyxoma benign tumors and in none of the malignancies. Early mortalities in the 3 groups were 8.2% (4/49), 0% (0/3), and 12.5% (1/8), respectively. Late mortalities were 9.5% (4/42), 0% (0/3), and 100% (7/7), respectively. One patient with myxoma had recurrence, the cause of which was likely to be inadequate resection. The late deaths in patients with malignancies were due to metastasis or local recurrence.

CONCLUSIONS

Benign tumors are generally curable if surgically excised. Preoperative refractory cardiac dysfunction or embolism should be avoided by the accurate evaluation on echocardiography. The prognosis of malignant tumors is poor if they are only debulked. However, aggressive surgery that can palliate obstruction and allow time for adjuvant therapy should be carried out.

Obstruction of St Jude medical valves in the aortic position: a consideration for pathogenic mechanism of prosthetic valve obstruction

Between 1995 and 2000, 8 patients with St. Jude Medical (SJM) valves in the aortic position required 9 redo valve replacement for prosthetic valve obstruction. Obstruction of the prosthetic valve was diagnosed by simultaneous echocardiography and cineradiography, and process of restricted leaflet movement that progressed to hemodynamic impairment was observed by serial studies in three recent patients. An oral anticoagulation was considered to be adequate in all patients except one patient who had withdrawal of warfrain. Pannus was the sole cause of valve obstruction in seven events in 6 patients, and both thrombus and pannus in 2 patients. Pannus overgrowth was found on the inflow aspect of the SJM valve, and involved the ends of the straight edge of the leaflets over pivot guards. These results suggest that pannus might play the primary role in development of obstruction of aortic SJM valves in patients on adequate oral anticoagulation.

[Long-term results of aortic root replacement for Marfan syndrome]

Between January 1974 and December 2000, aortic root replacement was performed for 46 patients with Marfan syndrome. The hospital mortality rate amounts to 8.6% (4 patients out of 46). Fifteen (35.7% of survivor) of 42 survivor died during the period of follow-up. Eighteen of 42 survivor were developed cardiovascular events of 21 times and 11 patients had to be reoperated on at least once for a total of 12 reoperations. Nine of 15 late death patient died in relation to aortic dissection and pseudoaneurysm of distal anastomosis and coronary anastomosis. Actuarial survival rate was satisfactory for 10 years after aortic root replacement, but sharply decreased after postoperative 10 years. The use of non-sealed graft, classical Bentall method, reoperation and inclusion technique were risk factors for the late death.

Postoperative intussusception after incidental appendicectomy

Postoperative intussusception of the appendiceal stump is a rare complication of appendicectomy. We report an infant who developed an intussusception of the appendiceal stump 2 days following an appendicectomy performed during a right inguinal herniotomy as a day case. The intussusception was diagnosed on ultrasonography and was to be treated laparoscopically, but spontaneous reduction occurred during induction of general anesthesia.

High-dose cimetidine reduces proinflammatory reaction after cardiac surgery with cardiopulmonary bypass

BACKGROUND

Cimetidine, which is usually used for gastric ulcer, enhances cellular immunity. The effect of cimetidine on perioperative proinflammatory response after cardiac surgery with cardiopulmonary bypass was investigated.

METHODS

Elective coronary artery bypass graft cases in which CPB was performed were placed randomly in a cimetidine (C) group (n = 20) or a no-treatment (N) group (n = 20). The time course of plasma levels of neutrophil elastase, interleukin (IL)-6 and IL-8, leukocyte counts, lymphocyte recovery ratio, C-reactive protein, creatine-kinase-MB, and oxygenation index were analyzed.

RESULTS

The plasma levels of neutrophil elastase and IL-8 were inhibited in the C groups at 2 hours after CPB termination. In a comparison of the two groups, the C group demonstrated higher lymphocyte recovery ratio and lower C-reactive protein on postoperative day 5 and shorter intubation time. No intergroup differences were observed in IL-6, leukocyte counts, creatine-kinase-MB levels, or oxygenation index.

CONCLUSIONS

Cimetidine may reduce surgical stress and augment the immune system after cardiac surgery with cardiopulmonary bypass.

Cytomegalovirus enteritis after autologous peripheral blood stem cell transplantation

A 61-year-old male with non-Hodgkin's lymphoma (peripheral T-cell lymphoma, unspecified, clinical stage IVb) received autologous peripheral blood stem cell transplantation (PBSCT) during first remission. He was seropositive for cytomegalovirus (CMV) prior to autologous PBSCT. His posttransplant clinical course was complicated by refractory CMV enteritis, which manifested persistent abdominal pain, diarrhea, and bloody stool. Generally, gastrointestinal CMV disease is relatively rare after autologous PBSCT. However, our case indicates that CMV infection must be considered as a differential diagnosis in cases of unexplained hemorrhagic enteritis following autologous PBSCT.

Peripheral ameloblastoma with potentially malignant features: report of a case with special regard to its keratin profile

A peripheral ameloblastoma with atypical features occurring on the left maxillary alveolar ridge of 40-year-old man is described, along with an immunohistochemical profile of its cytokeratin (CK). The lesion apparently originated from the surface gingival epithelium. The tumor nests or strands were highly cellular with a variable degree of squamous differentiation and microcyst formation. Occasional mitotic figures and dystrophic calcification, both of which are not seen in conventional ameloblastomas, were also observed. The tumor infiltrated deep into the alveolar mucosa, including the periodontal ligament, and showed histological and topographical evidence of atypism, resulting in resorption of the underlying alveolar bone. On the CK immunohistochemistry, CK19 was demonstrated in all the types of neoplastic epithelia, including microcyst-forming cells, densely packed round or spindle cells within the tumor nests, cells with squamous metaplasia, and peripheral tall columnar cells. The CK immunohistochemical findings suggest the lesion's cell of odontogenic origin; they may reflect an immature phenotypic expression of cell differentiation in the odontogenic epithelia during the tumor growth in the gingival mucosa.

Aortic dissections complicating open cardiac surgery: report of three cases

Between June 1991 and February 1999, three patients suffered ascending aortic dissection as a complication of cardiopulmonary bypass operations with aortic cannulation at our hospital. The dissection occurred during the operation in two of the three patients and several months after the operation in one. Among a total of 2207 cardiac operations performed during this period, the incidence of perioperative ascending aortic dissection was 0.14%. In addition to visual inspection and palpation, either epicardial or transesophageal echocardiography proved extremely useful for establishing an intraoperative diagnosis of ascending aortic dissection as a complication of open cardiac operation. One of the three patients underwent closed plication but subsequently died of vital organ ischemia. In this case, failure of reapproximation of the injured intima by closed plication might have led to extension of the dissection. Despite prolonged cardiopulmonary bypass and myocardial ischemic time, graft replacement of the ascending aorta was successfully carried out in the other two patients. Thus, we believe that graft replacement of the ascending aorta should be performed for patients with extensive aortic dissection complicating an open cardiac operation.

Repair of left ventricular rupture following mitral valve replacement concomitant with left atrial reduction procedure--intracardiac patch and extracardiac buttress suture

Rupture of the posterior wall of the left ventricle after mitral valve replacement is a dire complication associated with a very high mortality. This study reports a successful repair of type I left ventricular rupture, which occurred after mitral valve replacement concomitant with a left atrial reduction procedure, by combination of an intracardiac patch and an extracardiac buttress suture. In a case such as this, in which hemostasis is quite difficult to establish, this combination technique is particularly effective.

Surgical treatment of prosthetic valve endocarditis with left ventricular-aortic discontinuity: reconstruction of the left ventricular outflow tract with a xenopericardial conduit

BACKGROUND AND AIM OF THE STUDY

Aortic prosthetic valve endocarditis (PVE) with annular destruction presents a challenge that requires techniques to eradicate the infection and correct the hemodynamic abnormality.

METHODS

Between July 1, 1996 and March 31, 2000, six patients with native or PVE of the aortic valve and aortic annular destruction underwent surgical treatment. Of these patients, three (two men, one woman; mean age 71.0 years) had circumferential annular destruction of the aortic annulus, and formed the basis of this study. The microorganisms responsible for the infection were Streptococcus spp. in two patients and Staphylococcus aureus in one patient. In addition to aggressive debridement of the infected tissue, repair was achieved by reconstruction of the left ventricular outflow tract with a xenopericardial conduit and fixation of the new prosthetic valve to the conduit.

RESULTS

One patient with ventricular septal perforation, multiple systemic embolism and sepsis died of low cardiac output syndrome soon after surgery. Two operative survivors were followed up for 9 and 51 months, with no late deaths. No patient has experienced recurrent infection, pericardial patch aneurysm, or prosthetic valve detachment.

CONCLUSION

These operative procedures provide easy and secure fixation of the pericardial patch to the healthy tissue under excellent operative view, as well as a sturdy structure for the fixation of the new prosthesis, and complete exclusion of the abscess cavity from the blood stream.

Triple valve replacement with bileaflet mechanical valves: is the mechanical valve the proper choice for the tricuspid position?

A more durable mechanical valve may be a better choice for the tricuspid position than a bioprosthesis when the patient already has mechanical prosthesis in the left side of the heart. Eleven cases of triple valve replacement (total follow-up period, 49.5 patient years), all with mechanical valves, are reviewed to assess optimal valve selection. Nine patients had undergone a total of 12 previous cardiac surgeries. Three patients died in hospital (27.3%), but there were no late deaths among the survivors. Two cases of valve thrombosis in the tricuspid position occurred (linearized incidence: 4.04%/patient years) and 1 of these required reoperation. Because of this high incidence of valve thrombosis, the bileaflet mechanical valve is not considered to be the best choice. Even if mechanical valves are implanted in the left side of the heart, a bioprosthesis may be a better choice at the tricuspid position.

Left ventricular myxoma: report of a case

Although recent advances in echocardiography have made it easier to detect cardiac tumors, left ventricular myxomas are still rare and often not found until the patient presents with a history of syncopal episodes or systemic embolization. Left ventricular myxomas are usually benign and curable; however, unreliable excision of the myxoma due to poor visualization of the left ventricular cavity can result in recurrence. To prevent recurrence, it is necessary to select the most appropriate surgical approach to excise the myxoma completely. We report herein the case of a patient in whom surgical excision of a left ventricular myxoma arising from the posterior wall of the left ventricle was successfully performed.

Surgical treatment for graft stenosis after repair of an interrupted aortic arch: report of two cases

We report herein two cases of patients who underwent successful reoperation for graft stenosis after repair of an interrupted aortic arch (IAA). The first patient was a 10-year-old girl who suffered from upper limb hypertension 9 years after her initial operation. Cardiac catheterization revealed a pressure gradient of 55 mmHg across the repaired arch. At reoperation, a left subclavian turndown anastomosis was performed, following which the hypertension resolved and a cardiac catheterization done 5 years later demonstrated sufficient growth of the restored arch with no significant gradient. The second patient was a 17-year-old boy who suffered from general fatigue and intermittent hypertension 12 years after his initial operation. Cardiac catheterization revealed a gradient of 60 mmHg across the repaired arch. He underwent an extraanatomic ascending to descending aortic bypass employing an additional 18-mm graft, and a postoperative cardiac catheterization showed no gradient between the ascending and descending aorta. Our experience has shown that IAA should be repaired without prosthetic grafts if possible. Although extraanatomic bypass is useful for reducing the operative risks at reoperation, a large graft should be used to avoid the need for a third operation. For young children expected to outgrow a second graft, performing an endogenous anastomosis, such as a left subclavian turndown anastomosis, should be considered as an alternative.

Cardio-aortic operation in octogenarians

OBJECTIVE

Aging of the population is a current phenomenon in Japan, and life expectancy at 80 years old is getting longer. So we reviewed cardio-aortic operations on octogenarians at our institution.

SUBJECTS AND METHODS

Thirty-three consecutive octogenarian patients who had undergone cardio-aortic operations from 1992 to 1998 were studied. There were 14 men and 19 women. The mean age was 81.9 years. Of the 33, 19 patients (58%) were in New York Heart Association class IV, and 21 patients (64%) were operated on urgently or in emergency. The procedures undergone were operation for coronary artery disease in 17 patients, operation for valvular disease in 7 patients, operation for thoracic-aorta in 7 patients, and others in 2 patients.

RESULTS

The hospital mortality rate was 27% (9 patients). However, 89% of patients experiencing hospital death were in New York Heart Association class IV preoperatively and had required an emergency/urgent operation. On the other hand, there was only one hospital death (1/12, 8.3%) among the elective patients. The statistically significant risk factors for hospital death were renal insufficiency, shock, New York Heart Association class IV, intra-aortic balloon pumping, and longer cardiopulmonary bypass time. The one-, three-, and five-year-survival rate was 73%, 68%, and 55%, respectively. Of the survivors, 77% were in class I or II.

CONCLUSION

Although octogenarians' hospital mortality was still very high, the mid-term results were acceptable and the survivors' quality of life was satisfactory. These data suggested that we should operate on cardio-aortic patients before they reach a very serious state, especially in octogenarians.

Cerebral protection selection in aortic arch surgery for patients with preoperative complications of cerebrovascular disease

OBJECTIVE

Retrograde perfusion is gaining acceptance as a means of cerebral protection, but it remains unclear how long the brain is protected and whether it is effective in patients with preoperative cerebrovascular disease.

METHODS

From January 1989 to August 1999, 205 patients--118 male and 87 female patients who ranged 12 to 86 years old, mean: 65.5 years old--underwent surgery at our hospital for aortic arch aneurysm using cerebral protection. We focused on mortality, stroke incidence and perioperative risk factor between 2 groups--selective cerebral and retrograde cerebral perfusion--also studying patients with preoperative cerebrovascular disease that influenced postoperative stroke.

RESULTS

The hospital mortality was 11.7% (selective cerebral perfusion group: 12%, retrograde group: 10.9%). Stroke occurred in 11 patients (5.3%), 4.7% in the selective cerebral perfusion group and 7.3% in the retrograde group. Preoperative cerebrovascular disease does not appear to be a risk factor for postoperative brain damage in aortic arch surgery. Regarding total replacement of the aortic arch, the incidence of postoperative brain damage in the retrograde group with preoperative cerebrovascular disease was higher than that in another group (p = 0.072). Cardiopulmonary bypass time and selective cerebral perfusion time in the patients with postoperative stroke were significantly longer than that in non-stroke group.

CONCLUSIONS

Preoperative cerebrovascular disease did not appear to be a risk factor in postoperative neurological deficit in the selective cerebral perfusion group. Prolonged selective cerebral perfusion time and cardiopulmonary bypass time may, however, lead to brain edema and cause neurological deficit.

Tricuspid valve replacement with the St. Jude Medical valve: 19 years of experience

OBJECTIVE

The choice of the valve substitute in the tricuspid position remains controversial. A St. Jude Medical valve is a choice of valve substitute and its lower thrombogenicity and excellent hemodynamic performance have been reported even in the tricuspid position. However, little is known of the long-term durability of the St. Jude Medical valve in the tricuspid position. Our long-term experience of tricuspid valve replacement showed the higher thrombogenicity than we had expected, therefore, this study was done to reconsider our strategy for valve choice.

METHODS

This study reviewed 23 patient who underwent 25 tricuspid valve replacements with the St. Jude Medical valves from 1980 to 1997. The mean age was 40 years. Eleven patients (48%) were men. There were four in-hospital deaths (17%). The remaining 19 patients were all alive and followed from 2.2 to 19.0 years (mean 11.8 years).

RESULTS

The overall survival, including hospital mortality, was 83%, 10 and 15 years after surgery. Valve thrombosis occurred in six patients. Freedom from valve thrombosis was 78 and 70%, 10 and 15 years after surgery, respectively. The linearized rate of the valve thrombosis was 2.9%/patient-years. Six patients required reoperation. The mean interval to reoperation was 9.5 years. Freedom from reoperation was 83% and 75%, 10 and 15 years after surgery, respectively. The linearized rate of the reoperation was 2.8%/patient-years. No structural valve deterioration was found. Echocardiographic study showed that the function of the St. Jude Medical valve without valve-related complications was well maintained.

CONCLUSIONS

The higher thrombogenicity of the St. Jude Medical valve in the tricuspid position altered our choice of valve substitutes from the St. Jude Medical valve to a bioprosthesis which is lack of need for anticoagulant therapy except for juvenile patients who are able to maintain potent anticoagulant therapy.

Cerebral tissue oxygen saturation during percutaneous cardiopulmonary support in a canine model of respiratory failure

Percutaneous cardiopulmonary support (PCPS) has come to be applied for cardiopulmonary resuscitation and in the management of severe respiratory failure as well as severe heart failure. We investigated cerebral tissue oxygen saturation during PCPS in a canine model of respiratory failure using near-infrared spectroscopy. Animals were mechanically ventilated with 10% oxygen to make a respiratory failure model. Perfusion with PCPS was performed via the left femoral artery and switched to that via the right axillary artery. Cerebral tissue oxygen saturation was 54.2 +/- 3.4% during PCPS via the femoral artery and was 82.3 +/- 4.6% during PCPS via the axillary artery (p = 0.001). Hepatic tissue oxygen saturation was not significantly different. LV dP/dt max increased significantly after switching to the axillary blood supply (p = 0.001). Conventional PCPS may not have the capability of supporting cerebral circulation under severe respiratory failure without organic heart disease.

Eccentric roller type total artificial heart creating interatrial shunt

Creating an interatrial shunt to achieve left-right flow balance and modification of the blood chambers to improve the basic performance of the device were performed in developing an eccentric roller type total artificial heart (ERTAH). Smaller blood chambers reduce friction loss and increase durability and energy efficiency. We changed the left blood chamber volume of 60 ml to 40 ml and the right blood chamber volume of 53 ml to 35 ml compared with previous types. Designs of inlet and outlet ports were modified to prevent backflow. In the mock circulatory system, redesigning the blood chambers resulted in a 20% increase in energy efficiency, about a two-fold increase of cardiac output and improved durability compared to the previous type. In an animal experiment, the ERTAH operated at a driving rate of 160 rpm with a left flow rate of 6.0 L/min and a right flow rate of 5.4 L/min. Interatrial shunt flow rate was 250-400 ml/min.

Biocompatibility of heparin-coated extracorporeal bypass circuits: new heparin bonded bioline system

Biocompatibility of a new type of heparin-coated cardiopulmonary bypass equipment, the Bioline, was evaluated in coronary artery bypass surgery cases. The heparin-coated (H) group (n = 15; Quadrox Bioline oxygenator/reservior and Carmeda BioMedicus BP-80 centrifugal pump) was compared with the nonheparin-coated (N) group (n = 12; uncoated, otherwise similar oxygenator, centrifugal pump, tubing, and filter set). Both groups used full systemic heparinization. The peak values of neutrophil elastase, C3a, IL-6, and IL-8 at 2 h after cardiopulmonary bypass (CPB), and C3a levels at the end of CPB and at 2 h after CPB were significantly reduced in the H group compared with those of the N group. However, no statistically significant intergroup differences were observed in thrombin-antithrombin complex, D-dimer, beta-thromboglobulin, or platelet factor-4. No significant differences were observed in hemostasis time, postoperative 12 h blood loss, required amount of blood transfusion, or intubation time. In conclusion, the Bioline demonstrated partially improved biocompatibility, in terms of leukocyte and complement activation, and proinflammatory cytokine production. However, it did not improve platelet activation, coagulation, or fibrinolysis cascade under full systemic heparinization. As a result, the clinical beneficial impact seemed to be the minimum.

Obstruction of St Jude Medical valves in the aortic position: significance of a combination of cineradiography and echocardiography

BACKGROUND

Obstruction of the St Jude Medical valve (St Jude Medical, Inc, St Paul, Minn) is a rare but serious complication.

METHODS

Cineradiographic and echocardiographic evaluations of aortic St Jude Medical valves were simultaneously performed on 54 patients, with no signs of prosthetic valve dysfunction late after surgery.

RESULTS

Although closing angles of the leaflets corresponded closely with the manufacturer data, restricted opening of the leaflets (opening angle >/= 20 degrees ) was found in 16 (group D) of the 54 patients by means of cineradiography. The opening angles were equal to or less than 14 degrees in the other 23 patients (group N) and between 15 degrees and 19 degrees in the remaining 15 (group M). Doppler-derived transprosthetic pressure gradients were significantly higher (P =.03) and the velocity index was significantly lower (P =.003) in group D than in group N. However, no significant differences were found in those values between group N and group M. Replacement of the aortic St Jude Medical valves was performed in 5 of the 16 patients, and the remaining 11 have been followed up because of relatively low pressure gradients. The cause of restricted leaflet movement was pannus formation without thrombosis in 4 patients and valve thrombosis with pannus formation in one.

CONCLUSIONS

Reduced valve orifice area and restricted opening of the leaflets resulting from excess growth of pannus probably led to obstruction of the aortic St Jude Medical valves. A combination of cineradiography and echocardiography makes it possible to provide an accurate and detailed diagnosis of obstruction of the valve.

Plasma exchange for hyperbilirubinemia following implantation of a left ventricle assist system: a case report

A 49-year-old patient with end-stage dilated cardiomyopathy underwent implantation of a left ventricular assist system (LVAS). Although the systemic circulation seemed to be improved, the serum total bilirubin (Tbili) level increased sharply in the early postoperative period (preoperative Tbili, 5.7 mg/dl; postoperative day 3, 33.6 mg/dl). Plasma exchange (PE) was performed 7 times from postoperative day 4, and the Tbili level decreased to 16.3 mg/dl by postoperative day 11. Thereafter, serum Tbili normalized concomitant with improved circulatory condition. The cause of the hyperbilirubinemia was considered to be temporary right ventricular dysfunction or hepatic sinusoid endothelial dysfunction. The liver function was recoverable, so PE had been effective in this case. Unfortunately, the patient suffered a midbrain infarction and ultimately died. From this experience, PE is recommended if it is judged that liver function can be preserved and circulation is adequate, but its implementation should not be delayed. It is essential that LVAS is implanted before damage occurs to end-organ function and thus prevent hyperbilirubinemia.

ATS prosthetic valve motion: an in vitro analysis

BACKGROUND AND AIM OF THE STUDY

We have reported clinical findings that normally functioning open pivot ATS valves did not open completely. In order to analyze features of the ATS valve motion more precisely, in vitro tests were conducted.

METHODS

Opening angles and pressure gradients of the ATS valve were measured and compared with those of the St. Jude Medical (SJM) valve under steady flow, but with various outlet configurations. Second, opening angles of the two valves were measured under pulsatile conditions in two different outflow configurations: (i) a 'straight outlet' where the leaflets did not extend into the tapering outflow chamber, and (ii) an 'abrupt enlargement outlet' where the leaflets extended directly into the enlarged outflow space. Third, flow visualization studies were made under steady flow conditions in the straight and abrupt enlargement outlet conduits, respectively.

RESULTS

Under steady flow conditions, opening of the ATS valve was restricted in most outflow configurations; only when the outlet angle was 0 degrees did the valve open fully. The SJM valve opened completely in all downstream configurations. Despite restricted opening in the ATS valve, the pressure gradient was similar in both valves. Under pulsatile conditions, both valves opened fully in the straight outlet; however, in the abrupt enlargement outlet the ATS valve opened incompletely and the SJM valve completely. Substantial turbulent flow was observed at the outside of the leaflet and corners of the conduit, notably with the ATS valve.

CONCLUSION

This study showed that the ATS valve did not open fully except when the outflow was straight, and the leaflet did not extend into an enlarged downstream chamber. Structural features of the ATS, such as its axis being located close to the straight edge and its leaflets extending further downstream from the ring orifice, may cause this unique valve behavior.

[Hemodynamic assessment of the Carpentier-Edwards pericardial valve compared with the St. Jude Medical valve in the aortic position using dobutamine-stress echocardiography]

To assess the hemodynamic performance of the prosthetic valve in the aortic position, we examined dobutamine-stress echocardiography (DSE) to the patients underwent AVR with CEP valve or SJM valve. In 23 mm size, there were no significant differences between CEP group and SJM group in Peak velocity of the aortic jet (PV), peak pressure gradient (PPG) and effective orifice area (EOA). On the other hand, in 21 mm size, PV and PPG of the CEP group were significantly lower than those of the SJM group after DSE. The EOA of the CEP group was significantly larger than that of the SJM group after DSE. Our results suggest that the hemodynamic function of the CEP valve is superior to that of the SJM valve especially in small aortic annuli.

A case report of surgical treatment of quadricuspid aortic valve associated with regurgitation

A case of a 65-year-old woman who had a quadricuspid aortic valve associated with aortic regurgitation is reported. The patient had severe aortic regurgitation and four equally divided aortic cusps. The valve abnormality was detected by a transesophageal echo and an aortography. The incomplete aortic valve was excised and replaced by a St. Jude Medical prosthesis. Although this case had no coronary abnormality, a coronary displacement is often reported in quadricuspid aortic valve cases. In order to perform an operation safely, accurate information which is obtained by a non-invasive examination of the transesoph-ageal echo is quite valuable as it can indicate the need for further preoperative examinations of the coronary arteries.

Characterization by denaturing gradient gel electrophoresis of bacterial communities in deep groundwater at the Kamaishi Mine, Japan

Bacterial communities in groundwater collected from five different sites at the Kamaishi Mine were investigated by using denaturing gradient gel electrophoresis (DGGE). The bacterial cells in groundwater were collected on Millipore filters, and their nucleic acid was extracted by freeze-thaw cycles. A partial 16S rRNA gene was amplified by using a universal primer set by PCR. The PCR products were analyzed by DGGE. The band pattern of DGGE was essentially identical between two samples obtained from different depths in the same borehole (KH-1). Samples from the other sites differed from one another. The partial sequences of 16S rRNA genes (about 350 base pairs) isolated from bands were determined and analyzed for phylogenetic position. Almost half the sequences from two samples of the KH-1 belonged to the cluster of spore-forming, gram-positive sulfate reducer, Desulfotomaculum. The other bands also were related to those of obligate anaerobes. This suggests that the environment in both sites of KH-1 was highly anaerobic. Although only a few sequences were retrieved from the other sites, they were phylogenetically distanced from known isolates.

Newly designed eccentric roller type total artificial heart

We have produced an eccentric roller type total artificial heart (ERTAH). As the first step in the development of this ERTAH, we conducted simulations such as a numerical simulation, a mock test, and an acute animal experiment using DeBakey roller pumps to analyze the left-right balance during its operation. The next step was redesigning the blood chambers to improve energy efficiency and implanting the ERTAH with an interatrial shunt into an animal for evaluation of the in vivo performance of the device. In the simulations, shunt flow through the bronchial arteries was approximately 500-600 ml/min, and the interatrial resistance was varied from 2.9-7.7 mmHg.min/liter. Redesigning the blood chambers resulted in the mock test in a 20% increase in energy efficiency, about a two-fold increase in cardiac output and improved durability compared to the previous type in the mock test. In the animal experiment the ERTAH operated with a left flow rate of 6.0 liters/min and a right flow rate of 5.4 liters/min. The interatrial shunt flow rate was 250-400 ml/min. Creating an interatrial shunt is a useful method for balancing the blood flow between the left and right heart of the ERTAH. A decrease in friction resistance and the prevention of backward flow resulted in an increase in energy efficiency, cardiac output, and improved durability, in spite of downsizing the blood chambers.

Concentric wear of the Delrin disc in a Bjork-Shiley heart valve prosthesis: report of two cases

We report herein the cases of two patients who received replacement of aortic Bjork-Shiley Delrin (BSD) valves that had been implanted for over 20 years following the development of aortic regurgitation (AR) resulting from wear of a Delrin disc. Case 1 was a 61-year-old woman in whom echocardiography revealed marked left ventricular dilatation and moderate AR 23 years after an aortic valve replacement (AVR) with a 21-mm BSD valve. Case 2 was a 51-year-old woman in whom echocardiography revealed marked dilation of the right atrium and moderate AR 23 years and 8 months after an AVR with a 21-mm BSD valve, as well as a mitral valve replacement with a 3M Starr-Edwards (SE) ball valve and tricuspid annuloplasty. In both patients, the BSD valves were replaced with other mechanical valves at reoperation. Examination of the explanted BSD valves showed that the Delrin discs contained increases in the radial gaps and strut indentation grooves on the inflow and outflow surfaces. The type and magnitude of the wear on the Delrin discs in these valves were consistent with data reported in the literature for this valve design after similar implant duration.

MR findings in degenerated ovarian leiomyoma

Leiomyoma is one of the rarest solid tumours of the ovary. We report a case of a degenerated ovarian leiomyoma associated with pregnancy. MR findings are identical to those of degenerated uterine leiomyoma and it is difficult to differentiate between them. Ovarian leiomyoma should therefore be included in the differential diagnosis of subserosal uterine leiomyoma.

Simultaneous repair of cardiovascular disorders and pectus deformity in a patient with Sprintzen-Goldberg syndrome: A case report

We report a 12-year-old girl with Sprintzen-Goldberg syndrome (SGS) who was complicated with annuloaortic ectasia with aortic regurgitation, mitral valve prolapse with mitral regurgitation, and a severe pectus excavatum. In this patient, aortic root replacement, mitral valve replacement, and sternal elevation were simultaneously performed, and a version of Ravitch's procedure that was technically modified to support the sternum was used for sternal elevation. This modified sternal elevation technique gave excellent operative exposure, and maintained chest wall stability after the operation.

Aortic valve replacement for aortic regurgitation caused by aortitis

Between January 1984 and December 1998, 19 patients (16 with Takayasu's arteritis, 3 with non-Takayasu's aortitis) underwent surgical treatment for aortic regurgitation resulting from the aortitis. Of the 19 patients, 14 had aortic valve replacement (AVR) and 5 had aortic root replacement. One patient (5.3%) died of graft infection during the hospital stay. During the follow-up period, 1 (5.6%) of the 18 postoperative patients died of paravalvular leakage due to valve detachment, which also required redo-operations in 2 patients with non-Takayasu's aortitis. Both patients were operated on during the active phase of the inflammation without perioperative steroid therapy. Although transmural pledgeted sutures were used for replacement of the detached prosthetic valve in 1 of these 2 patients, disruption of the aortic wall resulted in recurrence of valve detachment. In the other patient, aortic root replacement was successfully performed with the Cabrol technique in the second operation. Perioperaitve steroid therapy plays an important role in preventing complications after AVR when the valve replacement is carried out during the active phase of the inflammation, and for patients with non-Takayasu's aortitis, aortic root replacement should be considered to reduce the tension on the suture line and the native aortic valve annulus.

Surgical treatment of a coronary artery fistula with concomitant saccular coronary artery aneurysm: a case report

An extremely rare case of a coronary artery fistula with a concomitant saccular aneurysm is presented. A 65-year-old woman, who had a history of chest bruising 5 years earlier, suffered from chest pain, which was diagnosed as being due to left coronary artery-pulmonary artery fistulae concomitant with a giant saccular coronary artery aneurysm. Suture closure of the afferent coronary artery to the aneurysm, aneurysmorrhaphy, and transpulmonary closure of coronary artery-pulmonary artery fistulae were performed. The postoperative course was uneventful and the patient was well at 3 months after the operation. Because the risk of surgery appears to be less than the potential development of fatal complications, it is recommended for the treatment of coronary artery fistula with a concomitant saccular aneurysm.

Recovery from lymphocytopenia following extracorporeal circulation: simple indicator to assess surgical stress

This study investigated whether the lymphocyte count is a useful indicator to assess surgical damage following extracorporeal bypass. In Study 1, to investigate the correlation between extracorporeal circulating time (ECCT) and lymphocyte counts, 40 elective CABG patients were studied retrospectively. The lymphocyte recovery ratio (LRR), which represented the actual lymphocyte count divided by the preoperative lymphocyte count, was determined preoperatively, and on postoperative day (POD) 1, POD 3, and POD 5. In Study 2, the correlation between the interleukin-8 (IL-8) level and LRR was examined prospectively in elective CABG patients (n = 20). We measured the LRR and serum IL-8 levels preoperatively and during extracorporeal circulation (ECC) at 5 min, at the end of ECC, and 1, 3, and 12 h following ECC termination. Study 1 showed that the LRR decreased until POD 1 and gradually increased thereafter. The LRR had a negative correlation with the ECCT. In Study 2, the IL-8 level demonstrated a time course opposite to that of the LRR; it increased until 3 h after ECC termination and declined thereafter. There was a significant negative correlation between the LRR on POD 3 and the IL-8 level at 3 h after ECC termination. In summary, long-term ECC induced significant and prolonged lymphocytopenia. The LRR had a negative correlation with IL-8. These results indicated that the LRR may represent the degree of surgical stress following ECC; therefore, the counting of lymphocytes can be a quite useful bedside monitor to assess surgical damage and prognosis.

Constrictive pericarditis following hemopericardium due to ascending aortic dissection: A case report

A 79-year-old woman, who had had no history of trauma, tuberculosis, or collagen diseases, was referred for examination of general fatigue and shortness of breath on exertion. Physical examination revealed engorged neck veins, hepatomegaly, and ascites with abdominal distention. On chest x-ray the cardiac shadow was slightly enlarged and bilateral pleural effusion was present. An electrocardiogram showed low voltage of the QRS complex. Computed tomographic scans revealed two lumens in the remarkably dilated ascending aorta and the severely thickened pericardium. Cardiac catheterization showed elevated right atrial pressure and elevated right and left ventricular end-diastolic pressures, in addition to a pressure record of early diastolic dip and end-systolic plateau in the right ventricle. Aortography demonstrated aortic dissection localized to the ascending aorta. On the basis of these findings, the diagnosis of chronic ascending aortic dissection complicated with constrictive pericarditis was made. After subtotal pericardiectomy, graft replacement of the ascending aorta and proximal aortic arch was performed with successful results. Her postoperative recovery was uneventful. Histological studies of the pericardium showed fibrosis and marked infiltration of the inflammatory cells. No findings of specific pericarditis such as tuberculosis or collagen diseases were detected.