Organization of the lipoprotein lipase gene of red sea bream Pagrus major

Lipoprotein lipase (LPL) is a key enzyme of lipid deposition and metabolism. To investigate the mechanism of lipid deposition in fish, as a first step, we have characterized the LPL gene of a marine teleost red sea bream Pagrus major by cDNA and genomic structure analysis. The red sea bream LPL gene encodes 511 amino acids and spans approximately 6.3 kb of the genome. The coding region is organized into ten exons and nine introns. In comparison with the LPL of other animals, the deduced amino acid sequence shows a high degree of similarity with a conservation of functional domains, e.g. catalytic triad, N-glycosylation sites, lipid and heparin binding regions. The 1.1 kb of 5' flanking region contains two CCAAT, sequences homologous to Oct-I site and response elements for hormones including glucocorticoid, insulin and thyroid hormone. The results of the present study will facilitate further study of the function and regulation of the LPL in non-mammalian vertebrates.

Possible involvement of endothelin-1 and nitric oxide in the pathogenesis of proliferative diabetic retinopathy

BACKGROUND

Overproduction of endothelin-1 (ET-1) and nitric oxide (NO) in the retina is demonstrated in experimental diabetic animals. To clarify the possible involvement of ET-1 and NO in the pathogenesis of diabetic retinopathy, the authors examined the vitreous levels of these principal endothelium-derived vasoactive substances in patients with proliferative diabetic retinopathy (PDR).

METHODS

Vitreous fluid was taken from patients with PDR (ET-1, n = 12; NO, n = 12) and from patients with macular holes as controls (ET-1, n = 10; NO, n = 10) at vitreous surgery. Endothelin-1 and NO metabolites were measured by radioimmunoassay and high-performance liquid chromatography based on the Griess method, respectively.

RESULTS

Endothelin-1 levels (mean +/- SE) were 21.5 +/- 1.7 pg/mL in the vitreous of patients with PDR and 16.7 +/- 0.7 pg/mL in the vitreous of patients with macular hole. There was a significant difference between patients with PDR and controls (P = 0.009, Mann-Whitney). Nitrate (NO3) was 49.8 +/- 5.0 micromol/L in patients with PDR and 24.2 +/- 2.8 micromol/L in patients with macula hole; it was also significantly elevated in patients with PDR (P = 0.004, Mann-Whitney), whereas nitrite (NO2) was not detected in this study.

CONCLUSION

These results indicate that ET-1 and NO may be related in the pathogenesis of PDR.

A male and hermaphrodite specific RAPD marker for papaya ( Carica papayaL.)

The random amplified polymorphic DNA (RAPD) technique was used to determine the sex of a dioecious species, Carica papayaL., with three sex types, male, female and hermaphrodite. A 450 bp marker fragment, named PSDM(Papaya Sex Determination Marker), exists in all male and hermaphrodite plants but not in the female plants so far analyzed. The DNA sequence of PSDM exhibited no significant similarity to previously reported sequences. A sequence-characterized amplified region (SCAR) marker, SCARps, was developed from PSDM to determine the sex of papaya. Southern hybridization, using PSDM as a probe, showed that PSDM exists in the male and hermaphrodite genomes, but not in the female genome. This result strongly suggests that PSDM is located on the chromosome region that is specific to the male and the hermaphrodite. SCARps is a suitable marker for the precise and rapid diagnosis of sex in papaya.

The effects of feeding condition and dietary lipid level on lipoprotein lipase gene expression in liver and visceral adipose tissue of red sea bream Pagrus major

The effects of feeding condition and dietary lipid level on lipoprotein lipase (LPL) gene expression in the liver and visceral adipose tissue of red sea bream Pagrus major were investigated by competitive polymerase chain reaction. Not only visceral adipose tissue but also liver of red sea bream showed substantial LPL gene expression. In the liver, starvation (at 48 h post-feeding) drastically stimulated LPL gene expression in the fish-fed low lipid diet, but had no effect in the fish fed high lipid diet. Dietary lipid level did not significantly affect the liver LPL mRNA level under fed condition (at 5 h post-feeding). In the visceral adipose tissue, LPL mRNA number per tissue weight was significantly higher in the fed condition than in the starved condition, irrespective of the dietary lipid levels. Dietary lipid levels did not affect the visceral adipose tissue LPL mRNA levels under fed or starved conditions. Our results demonstrate that both feeding conditions and dietary lipid levels alter the liver LPL mRNA levels, while only the feeding conditions but not dietary lipid levels cause changes in the visceral adipose LPL mRNA level. It was concluded that the liver and visceral adipose LPL gene expression of red sea bream seems to be regulated in a tissue-specific fashion by the nutritional state.

Modified ultrafiltration may improve postoperative pulmonary function in children with a ventricular septal defect

To evaluate the effectiveness of modified ultrafiltration (MUF) on ventricular septal defect (VSD) repair in children, we retrospectively examined 10 patients who underwent VSD repair with MUF at the Kinki University School of Medicine hospital between June 1998, and December 1998 (MUF group). These patients were compared with 14 patients who underwent the same procedure without MUF (control group) between January 1997 and June 1998. Systolic blood pressure and hematocrit values increased significantly during MUF. By the time of postoperative transfer to the intensive care unit, PaO2 was higher in the MUF group than in the control group (503.3 +/- 112.2mmHg vs 376.3 +/- 149.2mmHg; P = 0.0491), whereas A-aDO2 was lower in the MUF group than in the control group (171.9 +/- 109.2mmHg vs 301.1 x 150.4mmHg; P = 0.0449). These findings demonstrate that MUF had a beneficial effect on pulmonary function in children who underwent surgery to repair a VSD.

Onset of complete atrioventricular block 15 years after ventricular septal defect surgery

A 4-month-old girl with a ventricular septal defect underwent cardiac surgery. During the operation, complete atrioventricular block (CAVB) occurred, but on postoperative day 16 it converted to normal sinus rhythm with persistent complete right bundle branch block and left anterior hemiblock. Fourteen years after the operation, second-degree atrioventricular block was detected, but her general condition was good. Fifteen years after the operation, CAVB occurred. The intracardiac electrophysiologic recording revealed A-H and H-V block. A permanent pacemaker was implanted, and following the implantation she completely recovered.

Should the supplemental vein graft be anastomosed upstream or downstream of the internal thoracic artery (ITA) for ITA hypoperfusion?

BACKGROUND

This study was designed to compare internal thoracic artery (ITA) flow in different settings of supplemental vein grafting for ITA hypoperfusion.

METHODS

Fourteen dogs each received two coronary bypass grafts to the circumflex artery (CFX), using left ITA and vein grafts, and then the proximal CFX was ligated. The animals were divided into two groups. G-I dogs receiving the vein graft proximally to the ITA graft and G-II receiving the vein distally. ITA flow was evaluated regarding 1) effects of competition from the vein graft, and 2) pharmacological or physiological effects on the ITA's contribution to distal perfusion. Flow is expressed as a mean (ml/min).

RESULTS

ITA flow was 44.2+/-5.9 in G-I, and 45.7+/-6.5 in G-II (p=ns), when the vein graft was occluded. With a vein graft open, ITA flow decreased to 7.5+/-1.6 in G-I, and 6.8+/-1.8 in G-II (p=ns), and ITA's contribution to total perfusion requirements was 18% in G-I and 16% in G-II. Adenosine (0.2 mg/min/kg) increased the ITA flow in both groups, 18.4+/-3.2, and 16.3+/-3.8, respectively (p=ns), and ITA's contribution to distal perfusion was increased to 32% in G-I and 27% in G-II. In contrast, phenylephrine (0.003 mg/min/kg) decreased ITA flow and ITA's contribution to distal flow in both groups (6.1+/-1.1, 11% vs 6.2+/-1.4, 11%, p=ns), but increased vein flow significantly. Cardiac pacing (150 bpm) increased the ITA flow and ITA's contribution to distal perfusion equally in both groups (8.4+/-1.5, 16% vs 7.6+/-2.6, 15%, p=ns).

CONCLUSIONS

Supplemental vein grafting, whether it is placed distally or proximally, limits ITA flow and ITA's contribution to distal perfusion both in the resting heart and during the increased myocardial oxygen demand.

Optic cup enlargement followed by reduced optic nerve head circulation after optic nerve stimulation

PURPOSE

To investigate changes in optic nerve head (ONH) circulation, visual evoked potentials (VEPs), and ONH cupping after stimulation of the optic nerve.

METHODS

Electrodes were fixed above the optic chiasma in rabbits under general anesthesia. Screw-type electrodes for VEP recording were fixed on the dura. ONH circulation, intraocular pressure (IOP), and blood pressure (BP) were measured after the passage of a current of 0.1 mA for 0.1 second (weak stimulation), 1 mA for 1 second (moderate), 5 mA for 10 seconds (strong), or 25 mA for 10 seconds (severe). Normalized blur (NB), indicative of tissue blood flow and velocity, was measured in the ONH after each stimulation, by using a laser speckle circulation analyzer. Changes in VEP and ocular fundus were also recorded. The ratio of cup area (CA) to disc area (DA) was measured before and 4 weeks after stimulation. After all experiments, the ONH was histologically examined.

RESULTS

Weak stimulation increased NB in ONH for 10 minutes, whereas strong or severe stimulation significantly decreased NB for a longer time, in a dose-dependent manner. BP showed no significant change, except with severe stimulation. IOP was not significantly changed. VEP amplitude was reduced 30 minutes after strong stimulation. The CA-to-DA ratio was significantly increased 4 weeks after strong stimulation. In some rabbits, disc hemorrhage occurred, followed by enlargement of disc cupping, with slight gliosis.

CONCLUSIONS

Electrical stimulation of the optic nerve changed ONH circulation and VEPs and increased disc cupping. This technique warrants further investigation as an experimental model for normal-tension glaucoma.

Total cavopulmonary connection using a pedicled pericardial conduit for a patient with apicocaval juxtaposition

A 5-year-old boy, with a double inlet solitary ventricle, pulmonary atresia, and apicocaval juxtaposition underwent an extracardiac total cavopulmonary connection. A pedicled pericardial conduit was placed behind the ventricle to make a straight pathway between the inferior vena cava and pulmonary artery. This report presents a solution for managing patients with complicated heart defects with apicocaval juxtaposition during the completion of a total cavopulmonary connection.

Surgical treatment of pacemaker induced left innominate vein occlusion using a spiral vein graft

Superior vena cava syndrome due to transvenous pacing leads is an uncommon but potentially life-threatening complication. This case involves a 54-year-old man who developed left innominate vein occlusion due to a pacemaker lead. This complication induced a progressive swelling on the left side of his face, neck, arm, and upper chest. The left innominate vein occlusion was surgically treated using a composite spiral saphenous vein graft. Postoperatively, the patient has received anticoagulation therapy with warfarin to prevent thrombosis and, thereby, the long-term patency of the graft. He has undergone follow-up on a regular outpatient basis without showing any recurrence of clinical symptoms.

Follow-up study of coronary artery bypass grafting in patients with Kawasaki disease

BACKGROUND

The purpose of this study was to assess the long-term clinical outcome of coronary artery bypass grafting in pediatric patients with Kawasaki disease.

METHODS

Six patients (mean age, 9.3 +/- 1.6 years) underwent coronary artery bypass grafting between September 1985 and December 1992. The number of bypass grafts placed was 1 to 2 per patient (mean 1.3 +/- 0.5). The left internal mammary artery (IMA) was used as a bypass graft in 3 patients, bilateral IMA in 1, and saphenous vein in 3. All patients underwent postoperative evaluations after 1 month and between 5 and 10 years.

RESULTS

Follow-up ranged between 9 and 16 years (mean 12.6 +/- 2.7 years). Stress myocardial scintigraphy identified 2 patients with transient ischemia, one of whom died suddenly after 16 postoperative years. Coronary angiography demonstrated that the grafts of 5 patients were patent at both the short- and long-term follow-up. However, in 1 patient, the IMA that was grafted to the diagonal artery was occluded 1 month after surgery. Five survivors are in good health, without clinical angina.

CONCLUSIONS

We consider that coronary revascularization with bilateral IMA grafts may provide a more favorable prognosis in patients with severe Kawasaki coronary artery disease. Stress myocardial scintigraphy and echocardiography can be used effectively to follow such patients.

Disseminated cholesterol embolism after coronary artery bypass grafting

Blue toe syndrome caused by cholesterol emboli is a relatively benign disease. However, disseminated cholesterol embolism is a life-threatening condition. We describe here the case of a 71-year-old female admitted because of anterior chest pain and intermittent claudication. Following cardiac catheterization, warfarin potassium was administered. However, the patient's toes soon darkened bilaterally, and BUN and creatinine levels increased from the normal value. Skin discoloration and renal failure were improved after stopping warfarin potassium administration. The patient underwent coronary artery bypass grafting and left femoropopliteal bypass. Cerebral infarction and renal failure occurred postoperatively due to disseminated cholesterol embolism. The patient died from renal failure on the 16th postoperative day without regaining consciousness following surgery. For high risk patients, interventional procedures to the ascending aorta must be avoided. When CABG cannot be avoided for coronary revascularization, off-pump bypass and use of arterial grafts are recommended.

Antipruritic and antidermatitic effect of extract and compounds of Impatiens balsamina L. in atopic dermatitis model NC mice

We examined the effects of a 35% ethanol extract (IB) from the petals of Impatiens balsamina L. and the principal active compounds from IB on chronic and serious pruritus and the development of dermatitis using NC mice, a model of atopic dermatitis. IB at 100 mg/kg significantly inhibited serious scratching behaviour in the NC mouse with established dermatitis when administered i.v. 1 h before, or p.o. 24 h before the measurement. A 10 microg/kg dose of kaempferol 3-rutinoside and 2-hydroxy-1,4-naphthoquinone (lawsone) isolated from IB also inhibited scratching behaviour in the NC mouse with established dermatitis. When 4-week-old NC mice with no symptoms were administered orally 100 mg/kg/day of IB until 13 weeks of age, protection was also noted against scratching behaviour during the development of dermatitis. IB was effective for the prevention and treatment of atopic dermatitis.

Platelet-derived growth factor-BB: a survival factor for the retinal microvasculature during periods of metabolic compromise

PURPOSE

The aim of this study was to test the hypothesis that platelet-derived growth factor (PDGF) reduces ischemia-induced damage to cells in the retinal microvasculature.

METHODS

As a model of ischemia, pericyte-containing microvessels freshly isolated from the adult rat retina were exposed to the inhibitors of ATP synthesis, iodoacetate and antimycin A. Cell viability was assayed by trypan blue exclusion.

RESULTS

PDGF-BB significantly reduced cell death induced by chemical ischemia. The half-maximally effective concentration was approximately 15 pM. In contrast to PDGF-BB, which is the specific ligand for PDGF-beta receptors, ischemic death was not reduced by PDGF-AA, which does not activate the beta-receptors. The protective effect of PDGF-BB was blocked by tolbutamide, which is an inhibitor of ATP-sensitive potassium (K(ATP)) channels and mimicked by the K(ATP) channel opener, pinacidil. Nifedipine, which blocks voltage-gated calcium channels (VGCC's), also mimicked the protective effect of PDGF-BB. Consistent with PDGF-BB and nifedipine preventing cell death via a common mechanism, i.e., reducing VGCC activity, the maximal effects of this growth factor and the calcium channel blocker were not additive.

CONCLUSIONS

Our results indicate that PDGF-BB significantly reduces the vulnerability of retinal microvessels to damage caused by profound ischemia. During episodes of metabolic compromise, it appears likely that the opening of K(ATP) channels via activation of PDGF-beta receptors initiates an adaptive mechanism to enhance the survival of the retinal microvasculature.

Ischemic preconditioning and nicorandil pretreatment improve donor heart preservation

The present study investigated the effects of ischemic preconditioning (IPC) and nicorandil pretreatment on myocardial storage in a donor heart preservation model. Isolated rat hearts were separated into groups: group 1, non-preconditioned control group; group 2, 2.5 min of normothermic ischemia followed by 15 min of normothermic Langendorff perfusion (one IPC cycle); and group 3, 2 cycles of IPC. All hearts were subsequently stored in University of Wisconsin solution at 4 degrees C for 2, 4 and 6h, and the concentrations of high-energy phosphate metabolites were measured for each time point. Heart function parameters (aortic flow, coronary flow and cardiac output) were measured when the heart was reperfused following the 2, 4 or 6 h of preservation. The effects of nicorandil, an ATP-sensitive potassium channel opener, on heart function following preservation were also evaluated. Nicorandil was injected intravenously before heart harvesting. The results showed that the energy status was well preserved in the IPC groups. The 2-cycle IPC group showed better recovery of heart function following preservation. Pretreatment with nicorandil also improved functional recovery of the heart following preservation. The present study showed that IPC of the rat heart resulted in improved myocardial energy metabolism and functional recovery after hypothermic preservation, and that nicorandil has potential for pharmacological preconditioning in heart preservation for transplantation.

[Two-cusp plasty using a pedicled auto pericardial patch for the right ventricular outflow tract in complete repair of tetralogy of Fallot]

BACKGROUND

Pulmonary stenosis (PS) and regurgitation (PR) are major concerns late after transannular patching for tetralogy of Fallot (TOF). In this study, we reviewed the TOF patients undergoing transannular patching to reveal whether the valvuloplasty technique (two cusp plasty) improved long-term results. We also reviewed potential for grow of the pedicled autopericardial patch.

METHODS AND RESULTS

Since 1977, 151 patients underwent corrective surgery for TOF. Transannular patching was required in 58 (38.4%). PS and PR in the postoperative long-term period of these 59 cases were reviewed. 25 patients had the standard transannular patching (S-TAP), and 33 had two-cusp plasty (TCP). Pedicled autologous pericardial patch were used in 9 patients of TCP. Actuarial freedom from PS at 7 years was 70.8 +/- 9.2% in S-TAP and 79.2 +/- 8.3% in TCP, and there was no significant difference. Incidence of severe PR was significantly higher in S-TAP (7/24) than TCP (1/24) (p < 0.05). Actuarial freedom from PR at 7 year was 69.6 +/- 9.6% in the former and 95.8 +/- 4.2% in the later, respectively. The diameter of the pulmonary arterial annuals was augmented with the somatic growth in 6 patients with the pedicled pericardial patch.

CONCLUSIONS

Two cusp plasty was more effective to prevent PR in the postoperative long-term period, comparing to S-TAP. As the material of the patch, pedicled autologous pericardium showed satisfactory outcome.

Diabetes-induced disruption of gap junction pathways within the retinal microvasculature

PURPOSE

Microvascular damage caused by diabetes is a leading cause of visual loss. Identifying events early in the course of diabetic retinopathy may help in understanding and, perhaps, preventing this disorder. The hypothesis that cell-to-cell communication within the retinal microvasculature may be affected soon after the onset of diabetes was tested.

METHODS

Streptozotocin was used to induce diabetes in rats. To assess cell-to-cell coupling the gap junction-permeant tracer, Neurobiotin, was delivered via patch pipettes into pericytes located on microvessels freshly isolated from the retinas of diabetic and control animals. Subsequently, immunohistochemical methods revealed the extent of the intercellular spread of the tracer. Electrophysiological methods were also used to detect intercellular communication.

RESULTS

In retinal microvessels of control rats, Neurobiotin spread hundreds of micrometers from the tracer-loaded pericytes. However, within days after the onset of diabetes, this cell-to-cell coupling was dramatically reduced. In contrast, microvessels of insulin-treated diabetic rats showed no significant loss of intercellular communication. Consistent with protein kinase C (PKC) playing a role in the diabetes-induced inhibition of gap junction pathways, exposure of microvessels to a PKC activator (phorbol myristate acetate) markedly reduced tracer coupling.

CONCLUSIONS

Within retinal microvessels there is extensive cell-to-cell coupling, which is markedly reduced soon after the onset of streptozotocin-induced diabetes. The closure of gap junction pathways disrupts the multicellular organization of retinal microvessels and may contribute to vascular dysfunction.

Treatment of deep infection following thoracic aorta graft replacement without graft removal

Deep infection following thoracic aortic replacement constitutes an extremely serious and life-threatening complication, and its treatment remains a challenge to surgeons. We report our experience involving five patients in whom deep infection occurred around the graft. Four of the five patients were treated by emergency surgery and one was treated by elective surgery. Surgical procedures performed including hemiarch replacement in one case, total arch replacement in one case, suspension of aortic valve and ascending aorta replacement in one case, Bentall procedure in one case, and descending aorta re-replacement in one case. Methicillin-resistant Staphylococcus aureus was detected in four patients, methicillin-resistant Staphylococcus epidermidis in one, and Aspergillus in one patient from purulent discharge at the operative site. Reoperative debridement and irrigation drainage were carried out at an early phase of infection. Intermittent irrigation following the reoperation was performed in all cases. In addition, muscle flap filling or omental translocation was carried out in three patients. Although the reported principle of treatment for arterial graft infection is extraanatomical bypass or rereplacement after removal of the infected graft, such procedures may be technically difficult and have a high risk at the thoracic level. Local anti-septic irrigation, administration of antibiotics, and vascular-rich tissue filling are useful procedures, and it appears that it is not always necessary to remove prosthetic grafts.

Analysis of microsatellite instability and loss of heterozygosity in uterine endometrial adenocarcinoma

Microsatellite instability (MSI) and loss of heterozygosity (LOH) were examined in 60 cases of uterine endometrial adenocarcinoma, using 13 microsatellite markers. In non-Smad-related regions, MSI and LOH were noted in 13 of 60 (21.7%) and in 20 of 60 (33.3%) cases, respectively. Genetic alternation of TGF-beta RII was noted in 1 of 60 cases (1.7%). The frequency of MSI and LOH was highest in Stages III and IV, respectively. Cases with G2 carcinoma showed the highest frequency, but LOH frequency did not differ among G1, G2, and G3 carcinoma cases. In Smad-related microsatellite regions, MSI and LOH were noted in 10 of 60 (16.7%) and in 12 of 60 (20.0%) cases, respectively. The frequency of MSI and LOH was highest in Stages III and IV, respectively. LOH was seen only in the Smad2 gene but not in the Smad4 gene. Our results suggest that the alterations in MSI and LOH were associated with middle and late stages of carcinogenesis of endometrial carcinoma. Both MSI and LOH tended to show an association with moderate to severe atypia of carcinoma. Our results also suggest that genetic alteration of the Smad2 gene is more responsible for endometrial carcinogenesis than that of the Smad4 gene. However, the TGF-beta type II receptor gene was considered a minor target of genetic instability in endometrial carcinogenesis.

Crystal structure of a depsipeptide, Boc-(Leu-Leu-Lac)3-Leu-Leu-OEt

A sequential polydepsipeptide, Boc-(Leu-Leu-Lac)3-Leu-Leu-OEt (1) (Lac = L-lactic acid residue) has been synthesized by the segment condensation method. The sequential unit of 1, -Leu-Leu-Lac-, is consisted of two amino acid residues and one hydroxy acid residue. X-ray diffraction measurement with an imaging plate detector and a direct-methods procedure of Shake-and-Bake successfully revealed the crystal structure of 1. In the solid state, the 11-mer depsipeptide, 1, have clear alpha-helical conformation even with the three ester linkages.

Experimental heterotopic heart transplantation without cardiopulmonary bypass: auxiliary support for the recipient heart

BACKGROUND

Auxiliary cardiac support using heterotopic heart transplant is of considerable interest, but the outcome is not known. To investigate technical feasibility and the possibility of using auxiliary support from heterotopic heart transplantation without cardiopulmonary bypass, we evaluated hemodynamics including the pressure-volume relationship in experimental animals.

METHODS

In heterotopic heart transplantation, we tailored the donor heart by removing the pulmonary and tricuspid valves, and by wide removal of the inter-atrial septum. Next, we anastomosed the descending aorta and left atrium of the donor heart to the descending aorta and left atrium of the recipient, without using cardiopulmonary bypass. Consequently, declamping the recipient's descending aorta allowed the donor heart to fill with blood and to start beating. We performed hemodynamic assessments including the effects of adrenergic stimulation. We measured the pressure and volume relationship of the recipient heart by closing and opening inflow of the donor left atrium to change the pre-load of the donor left ventricle.

RESULTS

The donor left ventricle produced a systolic blood pressure that was augmented by the recipient blood pressure and responded to adrenergic stimulation. When inflow of the donor left atrium was opened, the pressure-volume loop of the recipient heart shifted to the left and pressure-volume area decreased. Simultaneously, the mechanical efficiency and E(max) (the slope of the end-systolic pressure-volume relationship) of the recipient heart increased when inflow of the donor left atrium was opened.

CONCLUSIONS

This transplant model, without cardiopulmonary bypass, is feasible and can be applied to transplant investigations as a working heart model on the basis of the response of adrenergic stimulation. The increased pre-load of the donor left atrium from the recipient left atrium resulted in a recipient leftward shift of the pressure-volume relationship, suggesting that this transplant model with adequate pre-load acts as auxiliary assistance in the recipient intrathoracic cavity.

Postischemic reperfusion injury can be attenuated by oxygen tension control

Oxygen-derived free radicals cause cytotoxic damage during reperfusion after a period of ischemia and the production of these free radicals may be proportionate to oxygen tension (PO2). The present study tested the hypothesis that oxidative damage may be limited by maintaining a more physiologic PO2 following ischemia. An experimental study in Wistar rats were mounted on a Langendorff apparatus was conducted to estimate baseline aortic flow (AF), coronary flow (CF), cardiac output (CO), systolic pressure (SP), heart rate (HR), and the rate-pressure product (RPP: HRxSP). The hearts were divided into 3 groups (n=7, hearts/group): group 1, hypoxic (PO2=300+/-50 mmHg) reperfusion; group 2, middleoxic (PO2=500+/-50 mmHg) reperfusion; and group 3, hyperoxic (PO2=700+/-50 mmHg) reperfusion. Following 30 min of warm ischemia, hearts in all groups were reperfused at each oxygen pressure. The recovery of cardiac function of each heart was measured at the end of reperfusion. Concentrations of lactate (LAC), lactate dehydrogenase (LDH), and creatine kinase (CK) in the coronary perfusate during reperfusion were measured. The recovery rate of CO, SP, and RPP in group 2 were all significantly better than in the other 2 groups. CK leakage in group 2 was significantly lower than in group 3. A clinical study was also conducted during elective coronary artery bypass grafts in 16 consecutive patients who underwent either hyperoxic (n=8, PO2=450-550 mmHg) or more physiologic (n=8, PO2=200-250 mmHg) cardiopulmonary bypass after aortic unclamping. The clinical study assessed CK-MB, LDH, LAC, and malondialdehyde (MDA) in patient blood prior to starting the surgical procedure and at 30 min and 3, 9, and 21 h after unclamping. Cardiac index (CI), central venous pressure, pulmonary capillary wedge pressure, systolic arterial pressure, and the dose of cathecholamines were also measured. Although no significant differences were present in the dose of cathecholamines, the CI in the more physiologic oxygen tension group was significantly higher than in the hyperoxic group at 3 and 6 h after unclamping. The levels of MDA in the more physiologic PO2 group was significantly lower at 30 min after aortic unclamping than in the hyperoxic group. The present results suggest that in the experimental as well as in the clinical study, high PO2 leads to myocardial reperfusion damage; however, maintaining a more physiologic PO2 during reperfusion following ischemia may attenuate reperfusion injury.

A case of Standford type B aortic dissection involving a right-sided aortic arch with mirror-image branching and right-sided descending aorta

Isolated right aortic arch with mirror-image branching is a rare congenital anomaly. To date, no case has been reported for aortic dissection involving a right aortic arch with mirror-image branching. We report here on a case involving a 58-year-old man in whom expanding type B aortic dissection was demonstrated in the right aortic arch with mirror-image branching and a right descending aorta. The patient was successfully treated by interposition of a prosthetic graft via a right posterolateral thoracotomy approach. We also reviewed the literature.