Chloride ions evoke taste sensations by binding to the extracellular ligand-binding domain of sweet/umami taste receptors

Salt taste sensation is multifaceted: NaCl at low or high concentrations is preferably or aversively perceived through distinct pathways. Cl^- is thought to participate in taste sensation through an unknown mechanism. Here, we describe Cl^- ion binding and the response of taste receptor type 1 (T1r), a receptor family composing sweet/umami receptors. The T1r2a/T1r3 heterodimer from the medaka fish, currently the sole T1r amenable to structural analyses, exhibited a specific Cl^- binding in the vicinity of the amino-acid-binding site in the ligand-binding domain (LBD) of T1r3, which is likely conserved across species, including human T1r3. The Cl^- binding induced a conformational change in T1r2a/T1r3LBD at sub- to low-mM concentrations, similar to canonical taste substances. Furthermore, oral Cl^- application to mice increased impulse frequencies of taste nerves connected to T1r-expressing taste cells and promoted their behavioral preferences attenuated by a T1r-specific blocker or T1r3 knock-out. These results suggest that the Cl^- evokes taste sensations by binding to T1r, thereby serving as another preferred salt taste pathway at a low concentration.

Human Adrenal Cortical Zone Changes With Aging

Background: Previous adrenal morphological studies have shown that the zona reticularis (ZR) and the zona glomerulosa (ZG) decrease in size with aging. Although several lines of evidence indicate that the hypothalamic-pituitary-adrenal axis becomes hyperactive in elderly, little is known about age-related transformations of the adrenal zona fasciculata (ZF). Objectives: To investigate the morphological and functional changes of the adrenal cortex across the adult life span, with emphasis on: 1) the understudied ZF, and 2) potential sexual dimorphisms. Methods: We used immunohistochemistry to evaluate the expression of several cortical proteins: aldosterone synthase (CYP11B2), visinin-like protein 1 (VSNL1), 3β-hydroxysteroid dehydrogenase type II (HSD3B2), 11β-hydroxylase (CYP11B1) and cytochrome b₅ type A (CYB5A). The ZF area was estimated by subtracting the VSNL1-positive (a ZG marker) area from the HSD3B2-expressing area (ZG and ZF). All captured images were quantitated by ImageJ. In addition, we employed liquid chromatography-tandem mass spectrometry to quantify the morning serum concentrations of 6 steroids: cortisol, 11-deoxycortisol (11dF), 17α-hydroxyprogesterone (17OHP4), 11-deoxycorticosterone (DOC), corticosterone, and androstenedione (A4). The Mann-Whitney U test and Spearman’s rank correlation coefficients were used for statistical analysis, as appropriate. Results: We included 60 adrenal glands from 30 men and 30 women, with ages between 18–86 years. The total cortical area was positively correlated with age (r=0.34, p=0.008), and this association was significant only in men (p=0.02). Both the total (VSNL1-positive) and functional ZG (CYP11B2-positive) areas declined abruptly with aging in men (r=-0.57 and -0.76, p=0.001 and p<0.0001, respectively), but not women (p=0.06 and 0.27, respectively). The CYB5A-positive area, marking the ZR, correlated negatively with age (r=-0.76, p<0.0001) in both sexes. In contrast, the estimated ZF area showed a strong positive correlation with age both in men (r=0.59, p=0.0006) and women (r=0.49, p=0.007), while CYP11B1-positive area remained stable across ages (p=0.86). Finally, we measured morning levels of 6 steroids in 149 men and 149 women, with ages between 21–95 years, matched for age and body mass index. Serum cortisol, corticosterone, and DOC levels remained relatively stable across ages (p=0.38, 0.64 and 0.25, respectively), while 11dF levels increased slightly with age (r=0.16 and p=0.007), particularly so in men (p=0.005). Expectedly, 17OHP4 and A4 declined with aging (r=-0.37 and -0.37, p<0.0001 for both). Conclusions: In contrast with the ZG and ZR, the ZF and the total adrenal cortex area enlarge with aging. An abrupt decline of the ZG occurs with age in men, but not in women, possibly contributing to sexual dimorphism in cardiovascular risk.

The Age-Dependent Changes of the Human Adrenal Cortical Zones Are Not Congruent

BACKGROUND

While previous studies indicate that the zonae reticularis (ZR) and glomerulosa (ZG) diminish with aging, little is known about age-related transformations of the zona fasciculata (ZF).

OBJECTIVES

To investigate the morphological and functional changes of the adrenal cortex across adulthood, with emphasis on (i) the understudied ZF and (ii) sexual dimorphisms.

METHODS

We used immunohistochemistry to evaluate the expression of aldosterone synthase (CYP11B2), visinin-like protein 1 (VSNL1), 3β-hydroxysteroid dehydrogenase type II (HSD3B2), 11β-hydroxylase (CYP11B1), and cytochrome b5 type A (CYB5A) in adrenal glands from 60 adults (30 men), aged 18 to 86. Additionally, we employed mass spectrometry to quantify the morning serum concentrations of cortisol, 11-deoxycortisol (11dF), 17α-hydroxyprogesterone, 11-deoxycorticosterone, corticosterone, and androstenedione in 149 pairs of age- and body mass index-matched men and women, age 21 to 95 years.

RESULTS

The total cortical area was positively correlated with age (r = 0.34, P = 0.008). Both the total (VSNL1-positive) and functional ZG (CYP11B2-positive) areas declined with aging in men (r = -0.57 and -0.67, P < 0.01), but not in women. The CYB5A-positive area declined with age in both sexes (r = -0.76, P < 0.0001). In contrast, the estimated ZF area correlated positively with age in men (r = 0.59, P = 0.0006) and women (r = 0.49, P = 0.007), while CYP11B1-positive area remained unchanged across ages. Serum cortisol, corticosterone, and 11-deoxycorticosterone levels were stable across ages, while 11dF levels increased slightly with age (r = 0.16, P = 0.007).

CONCLUSION

Unlike the ZG and ZR, the ZF and the total adrenal cortex areas enlarge with aging. An abrupt decline of the ZG occurs with age in men only, possibly contributing to sexual dimorphism in cardiovascular risk.

Intratumoral heterogeneity of the tumor cells based on in situ cortisol excess in cortisol-producing adenomas; ∼An association among morphometry, genotype and cellular senescence∼

Cortisol-producing adrenocortical adenomas (CPAs) are associated with ACTH-independent Cushing's syndrome and histologically composed of two cellular subtypes: compact (lipid-poor) and clear (lipid-rich) tumor cells. However, the details of hormonal and biological activities of these tumor cells have remained unknown, especially in CPAs. CPAs frequently harbored unique histological features different from those of aldosterone-producing adenomas (APAs) including a senescent phenotype. Therefore, we explored the association between morphological features and the immunoreactivity of steroidogenic enzymes in CPAs with different genotypes and compared them with cellular senescence markers as well as clinicopathological factors of the cases. Hormonal activities (3βHSD, CYP21A, CYP17A1, CYP11B1 and DHEA-ST) and cellular senescence markers (p16, p21 and Ki-67) within different morphological features (clear and compact) were evaluated in 40 CPAs. CPA genotypes (PRKACA, GNAS and CTNNB1) were examined by Sanger sequencing and then compared them with the factors above. p21 immunoreactivity was significantly positively correlated with that of CYP21A (p = 0.0110), CYP17A1 (p = 0.0356) and DHEA-ST (p = 0.0420) but inversely with tumor size (p = 0.0015). CYP21A (p = 0.0016), CYP11B1 (p = 0.0001), CYP17A1 (p < 0.0001) and p16 (p = 0.0137) immunoreactivity were all significantly higher in compact cells than those in clear cells. CYP17A1 (p = 0.0056) and 3βHSD (p = 0.0437) immunoreactivity was significantly higher in PRKACA-mutated than wild type CPAs. p16 immunoreactivity and serum DHEA-S level were both significantly higher in GNAS-mutated than PRKACA-mutated (p = 0.0250) and wild type (p = 0.0180) CPAs. Results of our present study did demonstrate that compact tumor cells were hormonally active and more senescent than clear tumor cells in CPAs. PRKACA- and GNAS-mutated tumor cells were more hormonally active and senescent than those without mutations despite the similar morphological features. We herein proposed a novel histological classification of the tumor cell subtypes based on in situ cortisol excess, genotypes and the status of cell senescence in CPAs.

Structural basis for perception of diverse chemical substances by T1r taste receptors

The taste receptor type 1 (T1r) family perceives ‘palatable' tastes. These receptors function as T1r2-T1r3 and T1r1-T1r3 heterodimers to recognize a wide array of sweet and umami (savory) tastes in sugars and amino acids. Nonetheless, it is unclear how diverse tastes are recognized by so few receptors. Here we present crystal structures of the extracellular ligand-binding domains (LBDs), the taste recognition regions of the fish T1r2-T1r3 heterodimer, bound to different amino acids. The ligand-binding pocket in T1r2LBD is rich in aromatic residues, spacious and accommodates hydrated percepts. Biophysical studies show that this binding site is characterized by a broad yet discriminating chemical recognition, contributing for the particular trait of taste perception. In contrast, the analogous pocket in T1r3LBD is occupied by a rather loosely bound amino acid, suggesting that the T1r3 has an auxiliary role. Overall, we provide a structural basis for understanding the chemical perception of taste receptors.

Nutrients taste perception is mediated by T1r receptors that discriminate specific tastes among their wide diversity. Here the authors present crystal structures of the ligand-binding domains of the fish T1r2-T1r3 receptor, providing a structural framework for its ligand recognition.

[Epicardial atrial pacing using an active fixation bipolar endocardial lead in children]

Good performance was observed over 10 years after implantation of bipolar epicardial atrial pacing using an active fixation bipolar endocardial lead in 3 pediatric patients with congenital heart block. The bipolar endocardial lead which was supposed to be fixed transvenously was implanted on the atrial surface by first screwing the lead's helix into the myocardium. The catheter was then laid down on the atrial surface, and both electrodes were wrapped by the atrial tissue. The good performance of this pacing lead seemed to depend on stable positioning of the electrode. This lead is superior to the commercially available, and steroid eluting epicardial bipolar pacing lead, on the point of its small size in head and body, and could be applied to dual chamber pacing in smaller children.

[Management of mediastinitis after pediatric cardiac surgery with continuous closed irrigation method]

Two cases are presented as a successful management for mediastinitis with the continuous closed irrigation method after pediatric cardiac surgery. The continuous closed irrigation method has significant advantages over conventional open irrigation method or muscle flap in pediatric cases, because the system is simple to handle and easy to wash out any infectious tissue debris without additional invasive intervention. However, adequate duration of the irrigation and subsequent antibiotic regimen is still unclear. We conclude that the continuous closed irrigation method is an effective management which is applicable to most of mediastinitis cases after pediatric cardiac surgery.

Persistent fifth aortic arch associated with type A aortic arch interruption. Histological study and morphogenesis

A male infant, having a persistent fifth aortic arch and interruption of the aorta distal to the left subclavian artery, underwent successful surgical treatment. A histological study of the excised segment of the aorta showed that the ductal tissue extended to the junction between the fifth arch and the descending aorta with consequent narrowing in the corresponding region. The ductal tissue, however, did not contribute to occlusion in the fourth aortic arch. The morphogenesis of this combination of aortic arch anomalies was also discussed.

Recovery of high-frequency QRS potentials following cardioplegic arrest in pediatric cardiac surgery

We examined the hypothesis that recovery of high-frequency QRS potentials at reperfusion is influenced by the duration of myocardial ischemia during cardioplegic arrest in pediatric cardiac surgery. Signal-averaged electrocardiograms were recorded after induction of anesthesia (baseline data) and every 1 to 5 minutes after aortic declamping in 14 patients aged 2 months to 6 years. The signals were processed with a band-pass filter between 80 Hz and 300 Hz to obtain high-frequency potentials in the QRS complex. The high-frequency QRS potentials (80-300 Hz) were expressed as the root mean square voltage over the filtered QRS complex. The high-frequency QRS potentials at baseline were 33.9 +/- 4.4 microV. They decreased to 13.7 +/- 9.6 microV 1 minute after aortic declamping (p = 0.005). Subsequently they gradually increased and then returned to the baseline level. The time that the potentials were over 90% of baseline value ranged from 10 to 35 minutes after aortic declamping. The recovery time of this reduction in the high-frequency QRS potentials correlated with the duration of aortic cross-clamping (r = 0.80, p = 0.0009) and the value of postoperative MB isozyme of the creatine kinase (r = 0.81, p = 0.0042). This study demonstrated that the high-frequency QRS potentials decreased at early reperfusion following cardioplegic arrest and then returned to preischemic levels. The recovery time of the high-frequency QRS potentials significantly correlated with cardioplegic arrest time and postoperative MB isozyme of the creatine kinase values. Our results raise the possibility that changes in high-frequency electrocardiographic signals in the QRS complex may reflect myocardial ischemia during cardioplegic arrest.

Right aortic arch with isolation of the left subclavian artery and bilateral patent ductus arterioses

Of the right aortic arch anomalies, a right arch with isolation of the left subclavian artery is the least common. In a neonate who had a right arch with isolation of the left subclavian artery and bilateral patent ductus arterioses, pulmonary artery steal phenomenon developed after ligation of the right ductus. We performed division of the left ductus and reimplantation of the left subclavian artery into the left common carotid artery.

Extended septoplasty for subaortic stenosis developed 19 years after double-outlet right ventricle repair

A 27-year-old woman developed subaortic stenosis 19 years after double-outlet right ventricle repair. Subaortic stenosis was caused by a narrow ring of fibromuscular ridge associated with a bulge of the underlying septal muscle. The aortic valve was bicuspid and stenotic. We conducted extended septoplasty, replacing the aortic valve. Postoperative cineangiogram showed an adequate left ventricular outflow pathway. Double-outlet right ventricle repair may thus be followed by subaortic stenosis as long as 19 years after initial surgery. This lesion was assumed due to acquired disease secondary to flow disturbances in the left ventricular outflow, so reconstructing an adequate outflow pathway is effective and appears to help avoid recurring stenosis.

Right coronary artery to left ventricular fistula associated with left ventricular aneurysm

An infant with right coronary artery to left ventricular fistula associated with left ventricular aneurysm successfully underwent a division of fistula under cardiopulmonary bypass. Follow-up angiogram showed the patency of the right coronary artery, no recurrence of fistula, and the regression of the left ventricular aneurysm. Because the lesion may progress with age, early diagnosis and surgical intervention are indicated to prevent later complications.

[A case of lateral femoral circumflex artery as a free graft for coronary artery bypass surgery]

A 46-year-old man had a three-vessel coronary disease. We performed quadruple coronary artery bypass grafting (CABG) with the left internal thoracic artery (LITA), right gastroepiploic artery (RGEA), saphenous vein and lateral femoral circumflex artery (LFCA). Postoperative coronary angiogram showed that the LFCA bypass graft was patent and supplied sufficient blood to the anastomosed vessel. There was no stenosis at the anastomotic site. However, the LFCA graft showed a string sign. Long-term follow-up and angiographic studies is necessary to establish the use of LFCA as an arterial free graft for coronary revascularization.

Low-dose protamine based on heparin-protamine titration method reduces platelet dysfunction after cardiopulmonary bypass

OBJECTIVE

The heparin-protamine titration method that uses the Hepcon hemostasis management system (Medtronic HemoTec Inc, Englewood, Colo) reduced blood loss in cardiac surgery in previous reports, but the mechanism is not fully understood. This study tests the hypothesis that reduced protamine administration preserves platelet function in human cardiac surgery.

METHODS

Platelet count, alpha-granule secretion, and aggregation to thrombin before and after cardiopulmonary bypass in human beings were evaluated. In the control group (n = 14), a fixed dose of protamine (3 mg/kg) was administered. In the titration group (n = 20), protamine doses were based on the heparin concentration measured by the Hepcon system.

RESULTS

Heparin concentrations before protamine administration were higher in the titration group (P =.0012), but protamine doses of patients in the titration group were markedly lower than those of the control group (P <.0001). During protamine infusion at a rate of 0.3 mg. kg(-1). min(-1), the percentage of granule membrane protein-140-positive platelets significantly increased in the control group compared with the titration group (18.8% +/- 8.6% vs 13.0% +/- 5.3%, P =.0188). After protamine administration, aggregation of washed platelets to thrombin recovered almost to the preoperative level in the titration group; however, it remained lower in the control group (20% +/- 20% vs 55% +/- 18%, P =.0009).

CONCLUSION

Low-dose administration of protamine, based on a heparin-protamine titration method, restores not only the blood coagulation but also the platelet responses to thrombin and attenuates platelet alpha-granule secretion during heparin neutralization. Overdose of protamine activates platelets and may predispose patients to excessive bleeding after cardiac surgery.

Lower extremity hematoma as a complication of warfarinization in patients with artificial heart valves

Four cases of lower extremity hematoma in patients undergoing anticoagulant therapy after heart valve replacement are herein reported, with special emphasis on the comparative diagnostic value of ultrasonography and computerized tomography. Although conservative management is sufficient for patients with no neurological impairment, needle aspiration after autolysis of the hematoma, which can be confirmed by CT study, is also recommended.

Aortic dissection in an elderly patient with atrial septal defect

We report a case of acute aortic dissection that occurred in the late course of surgically untreated atrial septal defect. A 60-year-old man with acute aortic dissection and atrial septal defect was operated on successfully, and we discuss the causal relationship between these two unusual conditions.

Atrial fibrillation after coronary artery bypass grafting. An increase in high-frequency atrial activity in patients with right coronary artery revascularization

The increase in atrial high-frequency activity has been reported as a marker of the risk of paroxysmal atrial fibrillation. The presence of proximal right coronary artery disease is a predictor of atrial fibrillation after bypass surgery, however, the potential mechanism remains controversial. In this study, high-frequency atrial activity to clarify the electrophysiologic background for the predisposition to have proximal right coronary artery disease leading to atrial fibrillation after coronary revascularization was investigated. Before and soon after coronary revascularization, frequency analyses were performed on the 100 ms segment at the end of signal-averaged P waves in 22 patients with right coronary artery disease as opposed to the 23 patients without disease. Under the spectrum curve, area ratio (AR50) and magnitude ratios (MR) were calculated as follows; AR50 = (area 20-50 Hz/0-20 Hz) x 100, and MR = (magnitude at 20, 30, 40 and 50 Hz, respectively/maximal magnitude) x 100. In patients with proximal right coronary artery disease, high-frequency atrial components increased significantly in the 20 to 50 Hz range after coronary revascularization, and the incidence of postoperative atrial fibrillation was higher than in those without disease. In patients without right coronary artery disease, the frequency distribution of P waves was unchanged. Postoperatively, the two groups showed the same atrial frequency distribution. This data suggests that the increase in high-frequency atrial activity after right coronary artery revascularization might be associated with the pathogenesis of postoperative atrial fibrillation.

Right thoracotomy as an alternative for redo mitral valve replacement and concomitant repair of the tricuspid valve

BACKGROUND

We report the results of a right thoracotomy for reoperation on the mitral plus concomitant procedures. Access to aorta or repair of other lesions by this approach is controversial. EXPERIMENTAL DESIGN AND SETTING: Retrospective study. Institutional practice (University of Tsukuba Hospital, Tsukuba Japan).

METHODS

Until 1995, 9 patients underwent right thoracotomy for mitral reoperation. The indication for this approach was no retrosternal space with the pericardium left open. Seven patients had deteriorated bioprosthesis, 1 periprosthetic valve leakage, and 1 re-stenosis. Four were associated with moderate tricuspid regurgitation. Operations were performed under fibrillation. Cardioplegia was used in 1.

RESULTS

Through thoracotomy, 4 underwent mitral valve re-replacement, and 4 mitral valve re-replacement plus tricuspid annuloplasty. One was abandoned because of severe pleural adhesion. No neurological injury, or perioperative myocardial infarction occurred.

CONCLUSIONS

The right thoracotomy was an effective alternative to repeat sternotomy for redo mitral valve operation. Also, concomitant repair of the tricuspid valve could be safely done by this approach.

Aprotinin inhibits plasmin-induced platelet activation during cardiopulmonary bypass

BACKGROUND

In the past few years, aprotinin has been used in cardiac surgery with impressive results of reducing blood loss, but several adverse effects of aprotinin also have been reported. One of the most likely mechanisms is the inhibition of plasmin by aprotinin, although this indirect effect has not been reproduced in all experimental studies.

METHODS AND RESULTS

We evaluated the platelet function and fibrinolytic activity during human cardiac surgery, with or without aprotinin. During cardiopulmonary bypass (CPB) in humans without aprotinin (n=16), decrease of platelet aggregation induced by thrombin, increase of alpha-granule secretion of platelet and microparticle formation, and increase of plasmin/alpha2-antiplasmin complex (PIC) were observed. In contrast, low-dose aprotinin (1.0 x 10(6) KIU), which was administered only into the priming fluid of extracorporeal circuits (n=10), maintained platelet aggregation induced by thrombin and reduced alpha-granule secretion and microparticle formation of platelets during CPB. In vitro, plasmin (0.8 CU/mL) released alpha-granules of washed platelets, and this activation was completely inhibited by aprotinin (10 KIU/mL).

CONCLUSIONS

Aprotinin has indirect effects to inhibit platelet activation, and this may partly explain the reduction of blood loss during cardiac surgery. To prevent the adverse effects, a single and minimal use of aprotinin is important. The results of in vivo and in vitro studies suggest that platelet preservation was demonstrated by the lower concentration of aprotinin (1.0 x 10(6) KIU per patient or 10 KIU/mL) compared with the concentration that inhibits plasma fibrinolysis.

[NO inhalation therapy for post-operative pulmonary hypertensive crisis of the case of truncus arteriosus]

Two-months-old baby underwent complete correction by Barbero-Marcial's procedure for type I truncus arteriosus. Postoperative hemo-dynamics was fairly stable immediately after the operation. However, the acute rise in pulmonary pressure occurred on the 2nd postoperative day. The pulmonary vasodilation therapy with prostaglandin E1 and amrinone had failed. Thirty ppm of inhaled nitric oxide (NO) was started and it resulted in an immediate decrease in pulmonary arterial pressure. Complete weaning from NO was achieved 9 days after surgery by simultaneous administration of PGE1 and amrinone. Although inhalation of NO reduced pulmonary arterial pressure, combination of PGE1 and amrinone with NO inhalation exerted a pulmonary vasodilation and brought the patient to full recovery in this case with pulmonary hypertensive crisis.

Absent pulmonary valve with intact ventricular septum presenting as cardiorespiratory failure at birth

Absent pulmonary valve with intact ventricular septum is a rare congenital anomaly. Most cases are not diagnosed until years after birth, although several cases have been reported in the literature in which cardiorespiratory distress developed during the neonatal period. We present a patient who showed improvement after fairly conservative therapy to alleviate the pulmonary vascular resistance, with ultimate palliative surgery. The aneurysmal dilatation of the pulmonary artery was for the most part confined to the proximal portion of the trunk, possibly because the ductus arteriosus was patent. The literature is reviewed.

[Aortic valve regurgitation due to quadricuspid valve: a report of complicated case]

A 66-year-old male with the congestive heart failure was diagnosed grade 4 aortic valve regurgitation due to quadricuspid valve associated with bacterial endocarditis, widely patent left coronary artery ostium, chronic renal failure, and secondary hyperparathyroidism. Coronary arteriography showed that the size of left coronary ostium was widely patent 10 mm in diameter, and trans-esophageal echo cardiogram revealed perforation and vegetations on the coronary cusps of the aortic valve.

[Anatomic correction of double-outlet right ventricle associated with hereditary spherocytosis--a case report]

A 3-year-old boy with hereditary spherocytosis (HS) underwent anatomical correction for double-outlet right ventricle. In addition to acute injury to the red blood cells during cardiopulmonary bypass, chronic mechanical trauma related to the presence of internal conduit and transannular patch must be considered in this patient with HS. We therefore performed splencetomy prior to cardiac surgery to prevent perioperative serious hemolysis. Preoperative examination showed the anatomy was considered suitable for REV procedure. The position of the aorta was anterior, VSD was classified as subpulmonic and associated with subvalvular stenosis. Under cardiopulmonary bypass, infundibular septum was resected and intraventricular tunnel was constructed. The pulmonary artery was transected at the level of the valve commissures and translocated onto the right ventricle without transection of aorta. Right ventricular outflow tract was reconstructed with a patch bearing monocusp. No serious complication due to hemolysis occurred perioperatively. Postoperative angiocardiography revealed no stenosis in both left and right ventricular outflow tract. The patient was discharged on the 57th postoperative day and is doing well.

[Management of postoperative pulmonary hypertensive crisis in children--indication and usefulness of inhaled nitric oxide therapy as a pulmonary vasodilator]

Among 176 pediatric patients who underwent open heart surgery from 1990 to 1996, 7 developed severe pulmonary hypertensive crisis (PHC) postoperatively. All patients were treated with conventional medical therapy consisting of hyperventilation and deep sedation. Prostaglandin E1 and/or amrinone were administered initially as a pulmonary vasodilator, and in 3 of the 7 patients this resulted in immediate improvement in hemodynamics. These patients subsequently weaned off ventilatory support and they were discharged from the hospital. In 4 other patients, pulmonary vasodilator therapy with prostaglandin E1 and amrinone had failed and they were treated with inhaled nitric oxide (NO). In all patients, inhalation of NO resulted in immediate decrease in pulmonary pressure without significant change in systemic arterial pressure. Two patients successfully weaned from the ventilator, whereas in 2 patients decrease in pulmonary pressure was transient. They developed airway bleeding and died as a result of respiratory insufficiency. Although inhaled NO effectively reduced pulmonary pressure in patients with PHC, this effect was not maintained over 12 hours in patients associated with bronchopulmonary dysplasia. In patients at risk for severe PHC, rapid treatment with NO inhalation after initial event as well as the prevention of lung injury caused by mechanical ventilation were found to be important in the postoperative management.

[Inhaled nitric oxide for postoperative pulmonary hypertensive crisis in a patient with complete atrioventricular canal associated with Down's syndrome: a case report]

Two-year-old boy with Down's syndrome was treated with inhaled nitric oxide for pulmonary hypertensive crisis after correction of complete atrioventricular canal and persistent ductus arteriosus. The acute rise in pulmonary pressure and hemodynamic instability occurred on 3rd, 4th and 6th post operative days and pulmonary vasodilation with prostaglandin E1 and amrinone had failed. Twenty ppm of inhaled nitric oxide effectively reduced the pulmonary pressure and the patient was subsequently weaned from ventilation. Inhaled nitric oxide exerted a pulmonary vasodilation without decreasing systemic pressure in this patient with postoperative pulmonary hypertensive crisis.

[Citrate and ionized calcium on extracorporeal circulation in pediatric cardiac surgery]

The control of optimum concentrations of ionized calcium Ca2+ during cardiopulmonary bypass is important in maintaining cardiac function and reducing reperfusion injury. Ca2+ may be in part dependent upon the serum level of citrate Cit in use of hemodiluted prime in pediatric cardiac surgery. The purpose of this study was to ascertain fluctuations of Ca2+ during bypass in relation to Cit and to study control of optimum Ca2+. Ca2+ and Cit was measured prior to and every 10 or 20 minutes during bypass in 12 children aged 21 days to 6 years. Of 6 patients (body weight less than 6 kg) received acid-citrate-dextrose (ACD) solution 20 ml before aortic declamp to give low Ca2+ for reducing reperfusion injury. Ca2+ showed initial drop and then gradually increased as the result of decreasing Cit. Ca2+ was inversely correlated with Cit (r = 0.85, p = 0.0001). When ACD 20 ml was added, Ca2+ significantly decreased from 1.00 +/- 0.13 to 0.65 +/- 0.13 mmol/l. However, Cit remained 24.3 +/- 13.3 mg/dl at the end of bypass. In conclusion, the results of this study suggest that gradually increasing Ca2+ during bypass may be related to the rate of citrate metabolism and the use of citrate for the control of Ca2+ remains questionable.

Influence of bypass grafting to the infarct artery on late potentials in coronary operations

BACKGROUND

Late potentials (LPs) after myocardial infarction identify the risk of arrhythmic events and sudden death, and the absence of anterograde flow in the infarct-causing occluded coronary artery frequently is associated with LPs on signal-averaged electrocardiography. The present study was designed to clarify the influence of revascularization of the infarct artery on the LPs in the late course after myocardial infarction.

METHODS

We studied 21 patients after myocardial infarction with positive LPs who had at least one occluded infarct coronary artery. We investigated the LPs on signal-averaged electrocardiograms on the day of elective coronary artery bypass grafting (CABG) and 1 week after CABG.

RESULTS

There were 25 infarct arteries in the study patients, 13 of which were grafted. The positive LPs disappeared soon after CABG in 13 patients, 10 of whom had grafts to all of the infarct arteries. The LPs persisted in 8, who received no graft to the infarct artery. One week after CABG, the LPs were still present in 4, all of whom had no graft to the infarct right coronary artery.

CONCLUSIONS

In patients with positive LPs late after myocardial infarction, grafting to the infarct artery eliminated the LPs soon after CABG.

[Postoperative bronchial stenosis associated with IAA complex and transendoscopic resection of intrabronchial granulation]

Problem with stenosis of the left bronchus was encountered in a patient with type B interrupted aortic arch complex after the arch reconstruction and pulmonary artery banding. Bronchoscopic study disclosed the intraluminal granulation of left bronchus and transendoscopic resection of the granulation successfully relieved the stenosis and brought the patient to full recovery.

[A percutaneously controllable pulmonary artery banding device: clinical application]

An optimal pulmonary artery banding is often difficult with a conventional banding technique. It often requires readjustment after closing the chest. So we developed a percutaneously controllable pulmonary artery banding device and applied it in three patients. This device consists of silicone balloon being pasted on a reinforced silastic plate and silicone reservoir. The balloon is applied around the pulmonary artery and the reservoir is implanted subcutaneously. The control of the banding is accomplished percutaneously through the reservoir using a needle with fluid-filled syringe. This device worked successfully in two patients for percutaneous readjustment of pulmonary constriction and congestive heart failure was decreased. This device may offer proper constriction of the pulmonary artery without any surgical procedures after banding and may reduce surgical morbidity and mortality of sick children.

[Application of large curved forceps for taping in cardiovascular surgery]

A new large curved forceps was manufactured for trial with the object of taping in cardiovascular surgery. Widely used and commercially available forceps could be utilized on the taping of large vessel less than 5 to 5.8 cm in diameter. With this new forceps, aneurysmally dilate great vessels (less than 8 cm in diameter) could be safely taped without compression of aortic wall. This forceps has already applied not only for the major vascular surgery, but also for the wearing of cardiac net in coronary artery bypass grafting.

Relief of airway compression by enlarged pulmonary artery--modified palliative suspension of the artery after plication

A new modification of the technique for plication and suspension of the pulmonary artery in critically ill infants and children is described. The technique consists of (1) left lobe thymectomy, (2) insertion of a polytetrafluoroethylene sheet to provide complete coverage of pericardium, (3) plication of dilated pulmonary artery and (4) suspension of plicated pulmonary artery to the left side of the anterior chest wall. We employed this technique in 7 patients with respiratory distress due to tracheal and/or broncheal compression with massive left-to-right shunt (5 patients) and with absent pulmonary valve (2 patients). Five of these patients (71%) could be weaned from the respirator in the postoperative phase with this surgery. Although this procedure is palliative, this simple technique might be one of the choices for critically ill infants and children.

Distal circulatory support for thoracic aortic operations: effects on intracranial pressure

Spinal cord ischemia can result from aortic clamping during thoracic aortic operations. The perfusion gradient for spinal cord perfusion is positively influenced by distal aortic pressure and negatively influenced by intracranial pressure (ICP). Hemodynamic and ICP changes were examined in a swine model of descending thoracic aortic surgery where distal aortic perfusion was achieved under one of three conditions: (1) clamping without support, (2) a passive aortofemoral shunt, or (3) a left atrium-femoral artery bypass system. With aortic clamping alone, ICP increased from 9.8 +/- 2.2 mm Hg to 15.2 +/- 2.8 mm Hg (p < 0.05). With passive shunting, ICP was decreased to 13.8 +/- 3.0 mm Hg, which was still significantly elevated above baseline. However, with active bypass, ICP remained at control level (9.8 +/- 2.2 mm Hg). Mean distal aortic pressure, which was 82 +/- 10 mm Hg in the control state, decreased to 20 +/- 0.5 mm Hg with clamping alone and to 39 +/- 9 mm Hg with passive shunting, whereas with active support, a distal pressure of 64 +/- 8 mm Hg was achieved. In contrast to passive shunting, active distal bypass results in maintenance of ICP at baseline levels and results in distal aortic pressure significantly greater than that achieved with either aortic clamping alone or passive shunting. Thus, active distal circulatory support produces the greatest salutary effect on the two determinants of the spinal cord perfusion pressure gradient: ICP and distal aortic pressure. This support modality may be the best adjunctive technique to maintain the spinal cord perfusion gradient and hence minimize the risk of ischemic injury.

[Early repair of postinfarction ventricular septal perforation: a case report of an improved surgical technique]

Accurate repair of postinfarction ventricular septal perforation (VSP) has mainly depended on the technique for friable septal reinforcement. Modified closure of VSP with Xenomedica patch was performed in 63-year-old male. Friable border of the septum was successfully sandwiched between horse-shoe shape prejett (right side) and main patch (left side). The advantages of this modified surgical procedure are as follows: (1) septum can be seen through horse-shoe shape patch (even when tying the mattress sutures; (2) Xenomedica patch is flexible enough for avoiding the cutting for friable septum, and is strong enough for sandwiching the septum.

[Thrombolytic therapy of thrombosed Björk-Shiley aortic valve prosthesis--report of four cases]

Prosthetic valve thrombosis is associated with high mortality. Thrombolytic therapy is a promising alternative to valve replacement in the management of prosthetic valve thrombosis. To determine the efficacy and safety of thrombolytic therapy for thrombosed Björk-Shiley aortic valve prosthesis, 4 patients who received urokinase intravenously for this disorder were analyzed. In 3 patients, the successful outcome was sustained in that they remained asymptomatic and did not require operative intervention during follow-up, which ranged from 17 to 101 months. In one patient clinical signs of mild congestive heart failure occurred. This patient was surgically treated by thrombectomy and debridement of the prosthetic valve. Failure of urokinase treatment to resolve the thrombus after 1 week indicates that tissue overgrowth or fibrous, organized thrombus is the cause of prosthetic malfunction. Surgical intervention for this problem should be considered only after thrombolytic therapy has been tried and has failed. Our experience with urokinase treatment of thrombosis of aortic Björk-shiley prostheses indicates that this form of treatment should always be applied before surgical intervention. We also attempted to define the optimum protocol of fibrinolytic therapy by clinical evaluation. A protocol for the safe treatment of thrombosed valve is urokinase in initially administered in the doses as 960,000 units for 24 hours, then followed by a maintenance infusion at the half dose every 24 or 48 hours later. Thrombolytic therapy should be continued for 1 week at least to prevent rethrombosis even normalization of valve function was documented clinically. Simultaneous heparin infusion of 10,000 units for 24 hours is then started to replaced by warfarin treatment adjusted to obtain optimal prothrombin times.(ABSTRACT TRUNCATED AT 250 WORDS)

[Influence of ionized calcium concentration during cardiopulmonary bypass on pediatric cardiac surgery]

Changes of serum ionized calcium concentration (Ca2+) during cardiopulmonary bypass (CPB) were analyzed in 30 pediatric cardiac patients less than 15 kg body weight. Ca2+ decreased suddenly after the start of CPB, and it gradually increased to the normal value. Citrate added to the stored blood for priming and its metabolism might play a role in these changes of Ca2+. Addition of adequate volume of calcium chloride to the priming prevented sudden decrease of Ca2+. Although addition of citrate before aortic declamp effectively decreased Ca2+ and may prevent reperfusion cardiac injury associated with hypercalcemia, there were no correlation between predeclamp level of Ca2+ and serum CPK and GOT levels.

[A case of coronary artery bypass grafting (CABG) in which root mean square total (RMST) improved markedly after redo-distal anastomosis]

A 59-year-old man underwent CABG with left internal thoracic artery (LITA) to the first diagonal branch and saphenous vein graft (SVG) to the right coronary artery (RCA). Pump off was quite uneventful, but re-anastomosis was done because bypass graft flow measured before the closure of chest was 6 ml/min, which was most likely due to sclerotic right coronary artery and technical error. After re-anastomosis, bypass flow of SVG to RCA was measured 95 ml/min. Root mean square total (RMST) immediately after aortic declamp for the first time was 39% compared with that measured prior to operation, but improved to 49% after aortic declamp at the second time. It recovered to 127% 2 days after operation, and 137% at 7th postoperative day. RMST indicates the total electropotential per unit time from the beginning to the end of QRS. It has the specificity to predict VT and postoperative pump failure. In this case, it is suspected that RMST may be a predictor that revascularization would be complete or incomplete in operations for ischemic heart disease.

[A case of Cabrol's procedure in which selective cerebral perfusion was necessitated]

A 69-year-old man underwent Cabrol's procedure for annuloaortic ectasia and complicated multiple cerebral infarction. Preoperative CT scan showed atherosclerotic changes from the aortic arch to descending aorta. During extracorporeal circulation, arterial cannulation was made through left subclavian artery to prevent cerebral infarction due to detouched atheroma from the descending aorta. Intraoperatively, the ascending aorta was also atheromatous and ulcerative. In this case, cerebral infarction was most likely due to detouched atheroma from the aortic arch in retrograde blood flow during extracorporeal circulation. To prevent this complication, selective cerebral perfusion during extracorporeal circulation should have been selected.

[Right thoracotomy to approach mitral or tricuspid valve in reoperation]

Four patients underwent mitral valve re-replacement, and required tricuspid annuloplasty in two, through a right thoracotomy. There was no major postoperative morbidity and recovery was full and uneventful. The indications for selection of this approach were isolated mitral valve disease or combined tricuspid and mitral valve disease, severe adhesion between heart and sternum on CT scan, intact aortic valve and no severe reduction of respiratory function. We recommend right thoracotomy to approach atrioventricular valves in selected situations in patients for reoperations.

[Two cases of coarctation complex associated with congenital esophageal atresia (Gross type C)]

Two cases of coarctation complex (CoA + VSD + PDA) associated with congenital esophageal atresia (Gross type C) were successfully treated with esophageal and two-staged cardiac surgery. The perioperative management of the two cases is discussed with special reference to circulatory, respiratory and nutritional problems. Case 1; A newborn was diagnosed as esophageal and cardiac anomalies and gastrostomy was performed followed by end to end anastomosis of the esophagus under receiving Prostaglandin E1 infusion. Although subclavian flap angioplasty (SFA) and pulmonary artery banding (PAB) were performed 1 month later, she had recurrent respiratory complications and malnutrition postoperatively due to bronchomalacia and gastroesophageal reflux (GER). Case 2; A newborn was diagnosed as esophageal atresia and underwent corrective surgery of it on the 1st day of life. After esophageal surgery congestive heart failure (CHF) developed progressively and CoA complex was evident by echocardiography 5 days later. SFA and PAB were performed 26th day of life. In spite of the palliative surgery for cardiac lesions, both patients had growth failure because of CHF, respiratory complications and malnutrition. As soon as the circulatory and respiratory condition improved, corrective surgery was performed and resulted in full recovery.

A reconsideration of surgery for mitral stenosis based on the extent of valvular distortion shown by two-dimensional echocardiography preoperatively

A twelve-year follow-up study was carried out with 98 consecutive patients operated on for pure mitral stenosis with open mitral commissurotomy (OMC) or valve replacement with porcine valves (MVR). Each patient had the extent of valve distortion diagnosed preoperatively by two-dimensional echocardiography as either grade I of the dome-formation type, grade II of the intermediate type, or grade III of the mass-formation type. Thirty grade I patients and 24 grade II patients underwent OMC and 44 grade III patients received MVR. The long-term survival and reoperation rates were significantly poorer with grade II than grade I patients and there was no statistical significance between grades II and III. However, the clinical conditions set by NYHA are significantly worse in grade II than in grade III. This can be clearly explained by the fact that the left atrial volume decreasing ratio (LAVDR) in the latest period, which was measured in patients with more than 7 years survival, remained nearly at the early postoperative value in grade III, while the LAVDR of grade II at the latest period grew worse and became insignificantly different from the preoperative values. This study clearly shows that when OMC is applied to grade II patients, frequent reoperations might be necessary because of poor hemodynamic conditions. Thus, it might be better to adopt MVR rather than OMC with grade II patients with moderately distorted mitral valves.

The sedative effect of intranasal midazolam administration in the dental treatment of patients with mental disabilities. Part 1. The effect of a 0.2 mg/kg dose

The purpose of this study was to determine the sedative effect of a 0.2 mg/kg dose of midazolam, administered intranasally, prior to performing various restorative dental procedures on a group of mentally disabled patients under local anesthesia and nitrous oxide/oxygen analgesia. Twenty-one patients, aged 4 to 21 years, all of whom had previously exhibited highly combative and resistant behavior toward dental treatment under local anesthesia, were sedated with 0.2 mg/kg midazolam. Only patients assessed as ASA anesthesia status I or II were admitted to the study. After administering the midazolam, each patient was allowed to rest before initiating the dental procedures. Behavioral patterns during the various procedures were rated on a behavioral rating scale of 1-7. Each patient served as his or her own control, comparing behavior with or without intranasal midazolam. The results showed a marked improvement in behavioral patterns after administration of intranasal midazolam. Ratings on a scale of 1-7 were noted as "markedly effective" and "effective" for 69.2% of those patients who received infiltration injection anesthesia, 93.8% under rubber dam, 76.2% during cavity preparation, 84.2% for restoration placement and 87.5% during pulpotomy procedures. The majority of patients were discharged within 150 minutes of intranasal instillation. Further studies are indicated to ascertain the most appropriate dose of intranasally administered midazolam.

[Biventricular heart assist using centrifugal pump and roller pump in profound ventricular failure after open heart surgery: a case report]

A forty-seven-year-old female with profound biventricular heart failure probably caused by coronary artery spasm after open mitral commissurotomy was successfully survived by mechanical circulatory support. Centrifugal and roller pumps were applied to left and right side circulatory assist respectively. Recovery of cardiac function was evaluated by transesophageal echocardiography and hemodynamic parameters during intentional low flow assist. Finally, she was weaned from assist after 136 hours. No systemic thromboembolism was recognized after pump removal. Combination of centrifugal and roller pumps could be applicable to biventricular heart assist without crucial complication.

[Long-term clinical results after aortic valve replacement with mechanical heart valves and mitral valve replacement with porcine valves]

Long-term clinical results of aortic valve replacement (AVR) with mechanical heart valves and mitral valve replacement (MVR) with porcine valves were analysed. Sixty-three patients received isolated AVR and 48 received isolated MVR. Sixty-eight patients with MVR including double or triple valve replacement were also added in order to evaluate the primary tissue failure (PTF). The patients with operative deaths were excluded. Survival rate at 11 years in AVR was 68 +/- 10% and 67 +/- 15% in MVR without statistical difference. At 11 years, 76 +/- 8% of the patients in AVR were free from valve-related complications in contrast with the poor result of 34 +/- 31% in MVR (p less than 0.01). Main cause of this poor result in MVR was PTF as indicated in following event free rates; 83 +/- 9% at 7 years, 61 +/- 25% at 10 years and 49 +/- 31% at 13 years. There was no statistical difference between patients of above 50 years and below 49 years in PTF. Valve-related death event free was 93 +/- 5% in AVR and 86 +/- 11% in MVR at 11 years (not significant), however, there was statistical difference in re-operation event free rate as 94 +/- 5% in AVR and 76 +/- 11% in MVR at 11 years (p less than 0.001). These results suggest that the use of porcine valves in mitral position is confined to the selected patients.

[MRSA infections in multiple trauma patients]

Multiple trauma patients requiring prolonged intensive care are at high risk of MRSA infections. Surgical debridement and proper antibiotic prophylaxis combined with isolation of this compromised host from indigenous bacteria are the mainstays of initial therapy to prevent this complication. If this develops postoperatively, the sites of infection vary among the patients, such as urinary tract, surgical wounds, the abdomen, respiratory tract, vascular catheters, etc. Clinical evidence of sepsis suggests that intra-abdominal and respiratory tract infection are major contributors to mortality. In a postoperative multiple trauma patient, with pneumonia, thoracic empyema, intraabdominal abscess, wound infection and sepsis caused by MRSA, surgical drainage of the abscess with systemic infusion of vancomycin was effective and resulted in full recovery.

[Surgical managements of the compression of trachea and/or bronchus associated with congenital cardiovascular anomalies]

From 1987 through 1990, 17 cases with tracheal and/or bronchial compression due to congenital cardiovascular malformations were experienced at our institutes. Respirator was required preoperatively in 10 patients (59%) due to severe respiratory symptoms by airway compression and narrowing. In all cases, bronchoscopy was carried out pre- or intra-operatively for the precise diagnosis and for the decision of operative procedures. Postoperatively 12 cases were successfully extubated and remained free of respiratory distress. We investigated the relationships among pre- and post-operative pressure ratio, preoperative flow ratio, requirement of preoperative respirator and indication for plication and suspension of pulmonary artery in the group of the patients, who had airway compression by the dilated pulmonary artery due to large left to right shunt. As a result of this investigation, these factors have no significant correlation. The severity of associated tracheomalacia might be a most susceptible cause, which required the preoperative managements with respirator and the surgical interventions to the dilated pulmonary artery. Infant with patent ductus arteriosus (PDA) could be surgically treated by the division of PDA through left lateral thoracotomy. If the left main bronchus shows complete obstruction after division of PDA, the additional surgical intervention like suspension of aortic arch is needed. Two cases were lost with reoperation and these suggested not only the priority of simultaneous repair of trachea and cardiovascular anomaly, but the necessity of minor intervention against adhesion (insertion of Gore-Tex sheet between suspended pulmonary artery and sternum) in the first-step palliative operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of stabilized hemoglobin as a component of cardioplegia on warm ischemic heart

Stabilized hemoglobin was utilized as a component of cardioplegia in isolated rat heart. While oxygen consumption and heart function was better preserved in long term after reperfusion, damage from reperfusion injury was suspected and reversed in part by diltiazem.