Genomic organization of human histo-blood group ABO genes

We have isolated human genomic DNA clones encompassing 30 kbp of the histo-blood group ABO locus. The locations of the exons have been mapped and the nucleotide sequences of the exon-intron boundaries have been determined. The human ABO genes consist of at least seven exons, and the coding sequence in the seven coding exons spans over 18 kb of the genomic DNA. The exons range in size from 28 to 688 bp, with most of the coding sequence lying in exon 7.

A bicuspid pulmonary valve is not a contraindication for the arterial switch operation

There are no obvious criteria concerning the optimal repair for complete transposition with bicuspid pulmonary valve if neither the organic changes in the valve nor the pressure gradient between the left ventricle and the pulmonary trunk are severe. Instead of intraatrial switching or intraventricular rerouting in such circumstances, we have proceeded to the arterial switch procedure in 6 patients with an adequate diameter of the pulmonary valve (greater than 100% of the calculated normal aortic orifice). Postoperative catheterization (at approximately 8 months after the procedures) showed no pressure gradient between the left ventricle and the neoaorta except for a finding of 34 mm Hg difference in 1 patient who had undergone simultaneous subpulmonary myotomy. Echocardiography (7 years later in the longest follow-up) has shown no more than slight regurgitation across the bicuspid neoaortic valve, with no progressive increase of blood velocity across the valve. From these results in the middle term, we conclude that the arterial switch procedure remains an option of choice for patients with initially bicuspid pulmonary valve, providing there is no severe subpulmonary stenosis.

[Diltiazem abolishes the effect of ryanodine in St. Thomas' Hospital cardioplegic solution on the post-ischemic functional recovery]

Calcium-induced calcium release (CICR) from sarcoplasmic reticulum (SR) may contribute to calcium depletion of SR during the infusion of cardioplegic solution, which may protect the intracellular calcium overload observed during myocardial reperfusion. We have, therefore, investigated (1) the ability of ryanodine-containing cardioplegic solution to enhance myocardial protection and (2) the influence of diltiazem, L-type calcium channel blocker, on the ryanodine-enhanced cardioprotective effect in the isolated working rat heart. Hearts (n = 6-8/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (Ca2+ = 2.4 mM). This was followed by a 3 min infusion of St. Thomas' Hospital cardioplegic solution containing (1) 0 nmol/L of ryanodine or (2) 1.75 nmol/L of ryanodine combined with various concentrations of diltiazem (0, 0.13, 0.25 and 0.50 mumol/L). Hearts were then subjected to 40 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). (1) The recovery of aortic flow (%AF) was 52.2 +/- 3.5% in the ryanodine-free group. (2) %AF was 72.0 +/- 1.4%, 50.0 +/- 2.6*, 61.7 +/- 3.2* and 58.3 +/- 2.8*% in the 0, 0.13, 0.25 and 0.50 mumol/L diltiazem groups, respectively (*p < 0.05 vs the 0 mumol/L diltiazem group). Creatine kinase (CK) leakage during Langendorff reperfusion was less in the 0 mumol/L diltizaem (plus 1.75 nmol/L ryanodine) group than the ryanodine-free group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Myocardial preservation by continuous perfusion of Krebs-Henseleit solution--the temperature dependency of the optimal perfusion pressure]

The aim of this study was to determine the temperature dependency of the optimal pressure in myocardial preservation by continuous perfusion with Krebs-Henseleit bicarbonate buffer (KHBB) solution. Hearts from Wistar male rats were perfused with KHBB solution and cardiac function (aortic flow) was measured using an isolated working rat heart preparation. In the preliminary experiment, hearts were then preserved using Langendorff perfusion with KHBB solution of 37, 20 or 4 degrees C for 2 hours at a perfusion pressure of 100 cmH2O. This was followed by 15 min of Langendorff perfusion (37 degrees C, 100 cmH2O) and 20 min working perfusion. The 37 degrees C group and 20 degrees C group exhibited better functional recoveries of aortic flow (%AF) in the post-preservation period compared to the 4 degrees C group. In the test experiment, hearts were preserved using Langendorff perfusion for 4 hours at 37 degrees C or for 8 hours at 20 degrees C at various perfusion pressures. At 37 degrees C, %AF after 4 hours of the preservation were 64.7 +/- 2.6, 69.0 +/- 3.2, 81.9 +/- 3.1, 94.7 +/- 3.3 and 63.5 +/- 4.0% (p < 0.05 vs the 100 cmH2O group) at the perfusion pressure of 100, 60, 20, 15 and 10 cmH2O, respectively. %AF after 8 hours of the preservation at 15 cmH2O was 56.3 +/- 2.5%. At 20 degrees C, %AF after 8 hours of the preservatin was 78.9 +/- 3.3, 81.9 +/- 2.3, 67.4 +/- 1.9 and 65.9 +/- 2.2% (p < 0.05 vs the 60 cmH2O group) at the perfusion pressure of 60, 30, 10 and 15 cmH2O, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of electroretinogram during systemic hypercapnia with intraretinal K(+)-microelectrodes in cats

PURPOSE

Systemic hypercapnia alters the intraretinal pH and metabolism and profoundly affects the vitreal electroretinogram (ERG). Using intraretinal K(+)-selective microelectrodes (ISMs), the authors examined the effects of systemic hypercapnia on ERG in the intact cat eye in vivo.

METHODS

Double-barreled K(+)-ISMs were used to record intraretinal, light-evoked [K+]o decrease, intraretinal ERG, vitreal ERG, and standing potential (SP) in the dark-adapted retina. Hypercapnia was induced by adding CO2 to the inhaled mixture of gas (without significant hypoxia).

RESULTS

The standing potential was elevated, and the vitreal ERG c-wave increased in amplitude whereas the b-wave decreased during hypercapnia. Intraretinal recordings showed that the amplitudes of slow PIII and the transepithelial (TEP) c-wave decreased. The slow PIII decreased more than the TEP c-wave. The light-evoked [K+]o decrease also was reduced, but no change was noted in the subretinal [K+]o.

CONCLUSION

The neural retina was more sensitive than the retinal pigment epithelium to the intraretinal acidification caused by systemic hypercapnia. However, the change in the SP and b-wave suggested complicated effects other than acidosis.

[Inhaled nitric oxide after Fontan type operation]

The indication of Fontan type operation has been extending, but some cases on the boundary of the indication resulted in low cardiac output syndrome (LOS) postoperatively. Recently the inhalation of nitric oxide (NO) has been revealed to produce selective pulmonary vasodilatation, and it has come to be applied in the clinical setting. We experienced a case of 6-year-old boy with complex cardiac anomaly in whom the inhalation of nitric oxide was remarkably effective for the LOS caused by increased pulmonary vascular resistance after Fontan type operation. In the case various conventional treatments failed to improve his LOS during the weaning from a respirator on the second postoperative day. After the initiation of the inhalation of nitric oxide at a concentration of 6ppm, a rapid decreasing of pulmonary artery pressure concomitant with an improvement of hemodynamics were obtained. We concluded that the inhalation of nitric oxide is an effective strategy for the increased pulmonary resistance after Fontan type operation.

A case report of MR imaging of traumatic hemobilia

The diagnosis of hemobilia is difficult. Computed tomography and ultrasonography generally yield only contributory information about blood or clots in the gallbladder but cannot demonstrate bleeding. This case report shows that magnetic resonance imaging (MRI) can not only demonstrate traumatic hemobilia in the gallbladder, and its origin, but can also determine active bleeding from liver lacerations and hematoma.

[Myocardial protection and the sarcoplasmic reticulum--the effect of ryanodine treatment prior to cardioplegic arrest on post-ischemic functional recovery]

Sarcoplasmic reticular (SR) calcium depletion may contribute to the myocardial protection against ischemia and reperfusion-induced injury. We have, therefore, investigated the effect of ryanodine-induced SR calcium depletion on the myocardial protection when given during Langendorff perfusion before ischemia in the isolated working rat heart. Hearts (n = 6/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (the first working perfusion), and then aerobically (37 degrees C) perfused with bicarbonate buffer containing 0, 1.75 or 7.00 nmol/L of ryanodine (a Langendorff perfusion). Hearts were then aerobically (37 degrees C) perfused (20 min) with ryanodine-free bicarbonate buffer (the second working perfusion). This was followed by a 3 min infusion of St. Thomas' Hospital cardioplegic solution, and then subjected to 38 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). After the ryanodine treatment, the percent reduction in aortic flow was significantly greater in the 7.00 nmol/L ryanodine group than in the control group. The post-ischemic recoveries of aortic flow were 39.1 +/- 3.3, 32.8 +/- 5.3 and 37.3 +/- 4.4% in the 0, 1.75 and 7.00 nmol/L ryanodine groups, respectively. There was no difference in the creatine kinase leakage during Langendorff reperfusion between the ryanodine-treated groups and the control group. Thus, ryanodine decreased the cardiac function after the ryanodine treatment, indicating a reduction in SR calcium content. Ryanodine, however, failed to improve the post-ischemic functional recoveries.(ABSTRACT TRUNCATED AT 250 WORDS)

[Successful aortic root replacement with pulmonary autograft in two infants]

Two infants with congenital aortic valve stenosis underwent successful aortic root replacement with pulmonary autograft. One of the patients was 9 months and weighted 4.2 kg, and the other was 10 weeks weighing 4.6 kg. The former had undergone balloon valvotomy with a resultant severe aortic regurgitation. Operative method was basically similar to that taught by Ross. In terms of the right ventricular outflow reconstruction, however, left atrial appendage was utilized as the posterior wall while equine pericardial monocusp patch formed the anterior wall in the former patient. In the latter, morphology of the left atrial appendage was not suitable for the same kind of reconstruction, and nonvalved equine pericardial tube was used. Both of the patients eventually gained satisfactory circulatory condition. Advantages of aortic root replacement with pulmonary autograft are good competence without residual stenosis, avoidance of anticoagulation, and the high potential of future growth. So this operation is especially indicated for neonates and infants with left ventricular outflow obstruction.

A comparative study usefulness of magnetic resonance imaging in the diagnosis of acute cholecystitis

The utility of magnetic resonance imaging (MRI) in the diagnosis of acute cholecystitis was evaluated in 72 consecutive individuals (5 healthy, 13 with chronic cholecystitis and silent gallbladder stones, 43 without biliary or diffuse liver disease, and 11 with acute cholecystitis and gallbladder stones) with a 0.5-T superconducting unit. On the T1-weighted (500/20) and less T1-weighted axial spin-echo images (620/25), the liver/gallbladder signal intensity ratio (mean +/- SD) was 2.5 +/- 0.51 (n = 5) and 1.8 +/- 0.29 (n = 8) in acute cholecystitis; 0.9 +/- 0.42 (n = 6) and 1.0 +/- 0.29 (n = 9) in chronic cholecystitis; and 0.9 +/- 0.14 (n = 5) and 0.8 +/- 0.19 (n = 43) in normal gallbladder, respectively. Our results indicate that the liver/gallbladder signal intensity ratio on the T1-weighted image may be a simple and reliable indicator for the diagnosis of acute cholecystitis; we suggest further investigation to confirm these results.

[Sarcoplasmic reticular calcium release and myocardial protection--effect of ryanodine on myocardial ischemia and reperfusion-induced injury]

Calcium release from sarcoplasmic reticulum (SR) may contribute to the intracellular calcium overload observed during myocardial ischemia and reperfusion. We have therefore investigated the ability of ryanodine to enhance myocardial protection when given before ischemia or during reperfusion in the isolated working rat heart. Hearts (n = 6-9/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (Ca2+ = 2.4 mM). In the first series of studies, this was followed by a 3 min infusion of St Thomas' Hospital cardioplegic solution containing various concentrations of ryanodine. Hearts were then subjected to 38 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). The recoveries of aortic flow (%AF) were 50.3 +/- 2.5% in the ryanodine free controls versus 55.2 +/- 5.8, 72.0 +/- 1.3 (p < 0.05), 61.0 +/- 4.3, 51.8 +/- 5.1 and 32.1 +/- 5.0 (p < 0.05)% in the 0.88, 1.75, 2.13, 2.50 and 10.00 nM ryanodine groups, respectively. Creatine kinase (CK) leakage during Langendorff reperfusion was reduced in the 1.75 nM group but was similar to control in all other groups. In the second series of studies, 3 min of cardioplegia without ryanodine and 38 min of ischemia (37 degrees C) were followed by 15 min of Langendorff reperfusion with 0, 0.09, 0.18, 0.88 or 1.75 nM ryanodine, %AF was 59.3 +/- 3.3%, 54.7 +/- 3.3, 53.8 +/- 3.5, 38.4 +/- 8.9 (p < 0.05) and 33.3 +/- 5.8 (p < 0.05)% in the 0, 0.09, 0.18, 0.88 and 1.75 nM ryanodine groups, respectively. CK leakage tended to increase dose-dependently.(ABSTRACT TRUNCATED AT 250 WORDS)

Double switch operation in cardiac anomalies with atrioventricular and ventriculoarterial discordance

Since June 1987, 10 of 19 consecutive patients with atrioventricular and ventriculoarterial discordance (average age 4 +/- 2 years) had undergone a double switch operation with the morphologically left ventricle used as a systemic ventricle. There were two combinations of procedures. Atrial switch combined with arterial switch was used in two patients who had a normal pulmonary valve. Atrial switch combined with ventriculoarterial switch by Rastelli's procedure was used in eight patients with pulmonary stenosis or atresia and a large ventricular septal defect. One early death and two late deaths have occurred in a postoperative follow-up period of up to 4 years. Subsequent problems were mainly related to the results of atrial switch procedures in patients who had a small atrium because of low pulmonary flow, especially in patients with apicocaval juxtaposition. Our experience suggested that the double switch operation would open a new era of definitive surgical treatment in half of the patients with atrioventricular and ventriculoarterial discordance.

DMSO preparation as a direct solubilizer of calcium bilirubinate stones

Despite considerable progress in operative techniques, biliary surgeons continue to encounter difficulties when treating patients with intrahepatic gallstones. We have experienced a significant number of patients in whom complete stone removal was impossible during an operation due to the anatomical complexity of intrahepatic bile ducts, and the variety in the size and hardness of the stones. Under such circumstances, the application of a direct solubilizer capable of dissolving intrahepatic calcium bilirubinate stones, might be a possible alternative. Up to now, however, only calcium chelating agents have been used for removing calcium from calcium bilirubinate stones, and they are not always effective. As a promising solution to this problem, we have now developed a direct solubilize for bilirubin complexes--a dimethyl sulfoxide (DMSO) preparation. DMSO is a well-known bipolar nonprotonic solvent. We prepared solutions of DMSO and performed toxicological studies by administering this preparation to rats and dogs. Biochemical indices of liver and renal function remained unchanged after 7-28 days of DMSO administration. Nor were there any histological changes in the DMSO-treated animals on systemic survey of various organs. On comparing the in vitro capability for solubilizing calcium bilirubinate stones, the DMSO preparation was consistently superior to a calcium chelating agent alone. The combination of a chelating agent with DMSO had the highest solubilizing capacity.

Intraretinal study of cat electroretinogram during retinal ischemia-reperfusion with extracellular K+ concentration microelectrodes

PURPOSE

Intraretinal electroretinograms (ERG) during retinal ischemia-reperfusion were analyzed to clarify which cells are affected in the cat dark-adapted eye.

METHODS

Ischemia was induced by raising the intraocular pressure above arterial systolic pressure in vivo. Double-barreled microelectrodes were used to record the intraretinal ERGs and the light-evoked [K+]o decrease in the subretinal space. Vitreal ERGs, the standing potential and the transepithelial resistance were also recorded.

RESULTS

After 10 minutes of ischemia, vitreal ERG b- and c-waves had recovered fully in 2 hours, and after 30 minutes of ischemia, recovered approximately 85% and 77% of their control amplitudes in 4 hours, respectively. At the early period of reperfusion after 10 minutes of ischemia we observed the supernormal c-wave (124% of its control amplitude, n = 10) with an elevated standing potential. The transepithelial potential (TEP) c-wave increased without changes of slow PIII and transepithelial resistance when the supernormal amplitudes occurred. The light-evoked [K+]o decrease in the subretinal space (90% retinal depth) in the area centralis recovered to about 90% of the control amplitude in 2 hours, and after 30 minutes of ischemia recovered to about 70% of the control amplitudes in 4 hours. The recovery courses of the slow PIII and TEP c-wave were almost the same as that of the light-evoked [K+]o decrease.

CONCLUSIONS

The temporary supernormal amplitude of the ERG c-wave was originated from the retinal pigment epithelium (RPE) during the early period of reperfusion after 10 minutes of ischemia. The photoreceptors, Muller cell and RPE are responsible for the changes in the light-evoked [K+]o decrease, a slow PIII and TEP c-wave, respectively. Intraretinal recordings suggested that after ischemia of 10 to 30 minutes duration, the responses of photoreceptors, Muller cells and the RPE recovered with a similar time course. These findings suggest that in all cases, primarily photoreceptors were damaged.

Prevention of lung injury during open heart operations for congenital heart defects

To elucidate free radical-induced lung injury associated with open heart operations for congenital heart defects, we studied 23 such patients. Maximum plasma chemiluminescence level (a marker of peroxylipids) in patients with pulmonary hypertension (n = 8) was higher than in patients with cyanotic disease (n = 8) (1,115.4 +/- 189.9 versus 728.8 +/- 48.3 counts; p < 0.05). There was a significant correlation between the maximum chemiluminescence level and preoperative pulmonary to systemic arterial pressure ratio (r = 0.929; p < 0.05). To investigate the effect of allogeneic leukocytes, we compared pulmonary hypertensive patients without allogeneic leukocyte transfusion during operation (n = 7) with the group with pulmonary hypertension. Both maximum chemiluminescence level during bypass (712.4 +/- 24.9 versus 1,115.4 +/- 189.9 counts; p < 0.05) and percent decrease in pulmonary arterial pressure after bypass (44.7% +/- 6.2% versus 28.2% +/- 4.5%; p < 0.05) were significantly improved, suggesting that depletion of leukocytes decreased the lung injury induced by free radical reaction.

Effects of intravenous superoxide dismutase and catalase on electroretinogram in the cat postischemic retina

We examined the effects of the antioxidant enzymes, 10,000 U/kg of superoxide dismutase (SOD) and 50,000 U/kg of catalase (CAT) on cat electroretinograms during the reperfusion after retinal ischemia. The intravenous administrations of SOD and CAT promoted the recovery of the c-wave after 30 min of ischemia but not the b-wave. At 5 min after onset of reperfusion, SOD- and CAT-treated eyes showed 90 and 110% recovery of the c-wave amplitude respectively, against 50% recovery in the untreated eyes. These results suggested that the oxygen-derived free radicals affected the retinal pigment epithelium at the early period of reperfusion.

Effects of sevoflurane and halothane on reperfusion-induced arrhythmia in the isolated rat heart

The effects of sevoflurane and halothane on reperfusion-induced arrhythmia in the isolated rat heart were examined. Reperfusion-induced ventricular fibrillation (VF) occurred in all rat hearts, and the duration of VF was 151 +/- 11 (mean +/- SEM) seconds in the control group (no anesthetics administered). Sevoflurane changed neither incidence nor duration of VF at 1, 2, and 3 minimum alveolar concentrations (MAC) of anesthetic. Halothane altered neither the incidence nor duration of VF compared with the control group at 1 MAC; however, at 2 and 3 MAC, halothane significantly reduced the incidence and duration of VF (P < 0.05 at 1, 2, and 3 MAC halothane: respective incidences were 100%, 18%, and 55% and respective durations, 82 +/- 27 seconds, 20 +/- 6 seconds, and 13 +/- 9 seconds). In the isolated rat heart, we found that halothane has antiarrhythmic effects against reperfusion-induced arrhythmia at 2 and 3 MAC. Sevoflurane, however, did not have any antiarrhythmic effects against reperfusion-induced arrhythmia at 1, 2, or 3 MAC.

[Direct gallstone dissolution therapy with GS-100]

We have developed GS-100, a new direct dissolving drug with strong dissolution property for cholesterol stone by supplementing d-limonene, a dissolvent used since 1974, with 30% medium-chain monoglyceride (MCM). The new drug was applied in 23 patients with gallbladder stones and three with bile duct stone. The presumptive analysis of the composition of the stones was drawn from the CT recordings. As non-invasive therapies, methyl tert-butyl ether (MTBE) dissolution and extracorporeal shock wave lithotripsy (ESWL), which are commonly used in Europe and America, have been reported as being favourable; however, GS-100 is superior in respect to safety and applicative dimension, suggesting of the possibility of using GS-100 as an important drug in the non-invasive therapy for gallstone in the near future.

MR imaging of traumatic hepatic laceration: evaluation and course of healing after surgery

Six patients with hepatic laceration underwent magnetic resonance imaging (MRI) at 0.5T. Acute hepatic laceration was slightly hypointense on T1-weighted spin-echo (SE) image, and hyperintense on T2- and proton-weighted SE images. Subacute laceration was heterogeneously intense on T1-weighted image and hyperintense on T2- and proton-weighted images. Consistent changes in signal intensity of postoperative hepatic laceration were observed. On T1-weighted image, the signal intensity at first increased and then decreased from periphery to the center. On the T2- and proton-weighted images, the laceration was uniformly hyperintense relative to the liver prior to the appearance and growth of a hypointense ring at its periphery. The appearance of the above changes in signal intensity was also observed in postoperative recurrent hemorrhage. The postoperative biloma had none of the above changes in signal intensity. Our cases show that MRI is effective in the evaluation of hepatic laceration and in the assessment of the course of healing after operation.

Elevated level of 8-hydroxydeoxyguanosine in DNA of liver, kidneys, and brain of Long-Evans Cinnamon rats

Long-Evans Cinnamon (LEC) rats, a mutant strain originating from Long-Evans rats, spontaneously develop hereditary hepatitis followed by hepatocellular carcinoma. The hepatic disorder in LEC rats is associated with their abnormal copper metabolism; metal-catalyzed reactions often give rise to oxygen radicals, which may be related to the carcinogenesis. By means of high-pressure liquid chromatography with electrochemical detection, cellular DNA damage caused by oxygen radicals can be assessed in terms of the amount of 8-hydroxydeoxyguanosine (oh8dG). We assayed the amount of oh8dG in DNA of liver, kidneys, and brain of LEC and Long-Evans Agouti (LEA) control rats in seven groups (n = 3 to 6) aged from 5 weeks to 24 months. Control rats, a healthy sibling line, were age-matched. The amount of oh8dG was correlated with the severity of the age-related clinical symptoms in LEC rats. The amount was higher in LEC rats than in the controls, especially in the liver at the acute stage of hepatitis. These findings suggest that oxygen radicals may be important in the carcinogenesis that occurs in LEC rats.

Increased lung injury in pulmonary hypertensive patients during open heart operations

To investigate lung injury in adult open heart operations during extracorporeal circulation, we measured plasma chemiluminescence levels. Nineteen patients were divided into two groups depending on preoperative pulmonary artery pressure: a pulmonary hypertension group (n = 11) and a control group (n = 8). Plasma samples were taken simultaneously from arterial and central venous lines at six different points during and early after operation. Arteriovenous difference of chemiluminescence (counts/10 seconds) increased significantly only in the pulmonary hypertension group (from -19.1 +/- 8.3 at the end of cross-clamping to 23.7 +/- 12.4 at the end of bypass; p < 0.01). There was a positive correlation between peak values of arterial plasma chemiluminescence and postoperative respiratory index in the pulmonary hypertension group (p < 0.05). In addition, during the first 12 hours postoperatively, arteriovenous difference of chemiluminescence in the pulmonary hypertension group changed significantly from negative to positive values (p < 0.05). These data suggest that free radical activity (detected by chemiluminescence) was deeply involved in lung injury during and also early after open heart operations, especially in pulmonary hypertensive patients.

Growth potential after root replacement of the right and left ventricular outflow tracts

A successful operation for acute and severe aortic regurgitation after balloon valvuloplasty together with mitral regurgitation is described in a 9-month-old infant. Aortic root replacement was performed using a pulmonary autograft, while the right ventricular outflow tract was reconstructed with an interposed left atrial appendage posteriorly and a heterologous pericardial patch anteriorly. Mitral valve reconstruction was also effectively accomplished. This combination of right and left ventricular outflow tract reconstruction has a good potential for growth and may provide a solution for the future in infants.

Effects of intravenous iodoacetate and iodate on pH outside rod photoreceptors in the cat retina

PURPOSE

Effects of intravenous iodoacetate (a glycolysis inhibitor) and iodate (a metabolism inhibitor selective to retinal pigment epithelium) on light-evoked alkalinizations and hypoxia-induced acidifications were studied in the dark-adapted cat retina, in vivo, to learn about pH regulation.

METHODS

pH was recorded in the extracellular space surrounding rod photoreceptors with double-barrelled H(+)-selective microelectrodes.

RESULTS

Intravenous infusion of 5 mg/kg iodoacetate-induced alkalinizations in the outer nuclear layer and suppressed both light-evoked and hypoxia-induced pH responses immediately. Iodate injection (30 mg/kg) produced acidifications in the subretinal space and affected light-evoked alkalinizations gradually but not hypoxia-induced acidifications.

CONCLUSIONS

These results suggest that rods glycolysis plays an important role in both light-evoked and hypoxia-induced pH responses. And the retinal pigment epithelium may have little concern with light-evoked alkalinizations except that it plays an important role in regenerating the rhodopsin to be needed for the light responses of photoreceptors. Furthermore, the finding of the intravenous-iodoacetate-induced alkalinization in the outer nuclear layer supports that acid production by rods in the dark is originated from glycolysis to support the dark current. The iodate-induced acidification in the subretinal space indicators that the retinal pigment epithelium might actively transport acids from the subretinal space to the choroid.

Molecular genetic analysis of the ABO blood group system: 3. A(X) and B(A) alleles

We have employed a PCR approach to determine the nucleotide sequences of the coding region in the last two coding exons of the histo-blood group ABO genes from one A(X) and one B(A) individual. Compared with A1 alleles, the (A(X)) allele has a single nucleotide substitution (T-->A at nucleotide 646) resulting in an amino acid substitution (phenylalanine-->isoleucine at amino acid 216). Compared with B alleles, the B(A) allele has two nucleotide substitutions (T-->C at nt. 657 and A-->G at nt. 703) resulting in an amino acid substitution (serine-->glycine at aa. 235). The amino acid substitution resulting from this B(A) allele is located at the second of the four amino acid substitutions which discriminate human A and B transferases, and the amino acid residue (glycine) is identical to that of A transferase suggesting the involvement of this amino acid or its surrounding area for the recognition and/or binding of the donor nucleotide sugars.

Molecular genetic analysis of the ABO blood group system: 4. Another type of O allele

We have encountered an allele which seems to be another type of O allele at the human histo-blood group ABO locus. We have determined the nucleotide sequence of this allele over the coding region in the last two coding exons. This allele does not possess the single-nucleotide deletion found common among all the O alleles previously analyzed. Compared with A1 allele, this allele has three nucleotide substitutions resulting in two amino acid substitutions. The introduction of these amino acid substitutions into the A1 transferase expression construct apparently abolished the enzymatic activity of A1 transferase.

Intraventricular repair for Taussig-Bing anomaly

Among 41 patients with Taussig-Bing anomaly who underwent intracardiac repair, 10 patients were treated by intraventricular rerouting repair. The ages at operation ranged form 1 month to 8 years (average 2 years 3 months). Primary repair was done in four (average age 2 years 7 months), and repair was done after pulmonary artery banding in six patients (average age 2 years 2 months). The relationship of the great arteries was side by side in nine patients and oblique in one. After extensive resection of the infundibular septum, a distance of 8 to 18 mm from the tricuspid ring or chordae to the pulmonary valve was obtained (24% to 71% of total circumference for the subaortic route). The subaortic route was created to obtain an internal diameter at least equal to that of the aortic route. Tricuspid chordal or papillary muscle reattachment was performed in two patients. There were no early or late deaths. Follow-up ranged from 1 year 4 months to 22 years 3 months (average 5 years 8 months), and reoperation was required in one patient for residual pulmonary stenosis. The intraoperative pressure gradient between the left ventricle and aorta was 0 to 24 mm Hg (average 10.3 mm Hg), and postoperative study showed the gradients to be less than 19 mm Hg (n = 8). The age at operation, left ventricular-aortic pressure gradient, and postoperative tricuspid regurgitation were not significantly affected by the presence of severe hypertrophy of the infundibular septum (n = 4). These results indicate that intraventricular rerouting may be feasible in most patients who have the Taussig-Bing anomaly with side-by-side or similar relationships of the great arteries, and the age and conal anatomic variations do not appear to be significant limiting factors.

Cardiopulmonary bypass and cellular immunity: changes in lymphocyte subsets and natural killer cell activity

To investigate whether cell-mediated immunity responses are suppressed or activated by the effect of cardiopulmonary bypass (CPB), we studied peripheral blood lymphocyte subsets and antibody-dependent cell-mediated cytotoxicity in 52 adult patients who had undergone open heart operations. Lymphocyte function also was studied with regard to mixed lymphocyte reaction, which indicates the amount of DNA synthesis of lymphocytes, and natural killer (NK) cytotoxicity, which represents the killing activity of NK cells on the tumor cells (K-562), in 11 patients. The total T lymphocyte (OKT3+ and OKT11+) number showed no significant change during CPB. Suppressor/cytotoxic T cell (OKT8+) and NK cell (Leu7+ and Leu11+) numbers were found to be remarkably increased. However, helper/inducer T cell (OKT4+) and B cell (Leu12+) numbers were decreased during CPB. Antibody-dependent cell-mediated cytotoxicity was elevated during CPB. All of these changes were almost returned to the preoperative levels by the seventh day after operation. Mixed lymphocyte reaction and NK cytotoxicity were also activated during CPB. The results show that heart operations in which cardiopulmonary bypass is used are associated with activation of cytotoxic cell-mediated immunity.

[Clinical application of recombinant human SOD for the protection of ischemia reperfusion injury during open heart surgery]

We have applied recombinant human superoxide dismutase (RH-SOD) to prevent ischemia reperfusion injury in the patients who received open heart surgery. Twenty-four patients were divided into 2 groups; group A had no treatment as control and group B received bolus injection of RH-SOD (35,000 IU/kg) into cardiopulmonary bypass 5 minutes before reperfusion. Arterial and coronary sinus blood was collected to measure chemiluminescence (ChL) value, SOD activity, lactate and pyruvate level, and several parameters of myocardial oxygen metabolism after reperfusion. Arterio-venous difference of ChL value showed the tendency of less ChL generation of the heart in group B compared with those in group A. But no other parameters showed significant difference between the two groups. Our data suggested that this way of the administration of RH-SOD failed to improve the myocardial protection during open heart surgery. Further investigation, such as dose response study, might be required to determine whether RH-SOD possess beneficial effects or not in the clinical setting.

[A case report of successfully corrected 26 days old infant of tetralogy of Fallot with absent pulmonary valve]

A female infant weighing 2.4 kg had respiratory distress at birth. She became dyspneic and hypercapnic and required intubation with assisted ventilation 11 days after birth. Because cardiac failure and respiratory failure did not improve, she underwent total correction at 26 days old, which consisted of VSD closure, right ventricular outflow tract reconstruction with valved porcine pericardial roll (VPR) and plication of both pulmonary arteries. She was weaned from the ventilator 11 days after operation and discharged at 12 weeks of age. One year later, reoperation was successfully performed for the replacement of the stenotic VPR with a transannular patch.

Molecular genetic analysis of the ABO blood group system: 2. cis-AB alleles

We have determined the nucleotide sequence of the coding region in the last two coding exons of ABO genes from two cis-AB individuals (genotype cis-AB/O) with no consanguinity. In this region, cis-AB alleles from these 2 individuals were identical to one another while different from the A1 allele by two nucleotide substitutions. Both of these nucleotide substitutions result in amino acid substitutions. The first substitution is identical to the one previously found in the A2 allele. The other substitution is found at the fourth position of the four amino acid substitutions which discriminate A1 and B transferases.

Molecular genetic analysis of the ABO blood group system: 1. Weak subgroups: A3 and B3 alleles

We have determined the nucleotide sequences of the coding region in the last two coding exons of ABO genes (which occupy 91% of the soluble form of A1 transferase) from 7 individuals with weak subgroup phenotypes. Four of the individuals had an A3 phenotype and 3 individuals had a B3 phenotype. We determined the nucleotide sequences based on PCR followed by subcloning and DNA sequencing of the amplified fragments. Two cases of the A3 allele and 1 case of the B3 allele were found to contain a single-base substitution which resulted in an amino acid substitution. However, no other cases of A3 and B3 alleles were found to contain differences in this region. This finding demonstrates for the first time heterogeneity among these weak subgroups at the nucleotide level.

Effects of ischemia-reperfusion on light-evoked alkalinization outside rod photoreceptors in the cat retina

The effects of ischemia-reperfusion on the light-evoked alkalinization, which reflects the metabolism of rod photoreceptors, were studied in the dark-adapted cat retina in vivo. We recorded the pH value in the extracellular space surrounding rod photoreceptors with double-barreled H(+)-selective microelectrodes. The light-evoked alkalinizations at the outer nuclear layer were diminished during reperfusion after 10-30 min of ischemia which was induced by an increase of the intraocular pressure above the arterial systolic pressure. This result suggests that the rod metabolism might be suppressed during reperfusion after ischemia.

[Surgical management of tetralogy of Fallot with absent pulmonary valve in infancy]

Between November, 1987 and May, 1990, definitive operation was performed in 7 infants for tetralogy of Fallot with absent pulmonary valve. Preoperative respiratory failure was serious in 5 patients and semi-emergency operation was done. Surgical procedure consisted of closure of ventricular septal defect, reconstruction of right ventricular outflow tract using heterograft valved pericardial roll and plication of aneurysmally dilated pulmonary artery with or without pulmonary artery suspension in 5 infants with severe respiratory distress and heart failure, operated on 26 days to 5 months of age. In the other two less symptomatic infants, operated on at 13 months of age, reconstruction of right ventricular outflow tract was performed by transannular bovine pericardial patch with monocusp. There were no operative death and six infants are doing well 6 months to 3 years postoperatively, but one patient died of prolonged respiratory infection and respiratory failure one year after operation. Postoperative pulmonary arteriogram revealed a 42 to 61 (mean 54) percent reduction in right and left pulmonary artery size in 3 patients who underwent extensive plication of pulmonary artery. We suggest that definitive plication with or without suspension of pulmonary artery, together with closure of ventricular septal defect and reconstruction of right ventricular outflow tract is supposed to eliminate air way obstruction.

Effects of iodate on intraretinal b and c waves of the cat electroretinogram

In 12 cats, the intravenous and intravitreal administrations of sodium iodate (SI) were performed to examine the effects on b and c waves of electroretinogram in the dark-adapted retina. The intravitreal SI (0.5-3.5 mM) produced the complete suppression of intraretinal b waves without remarkable changes of slow PIII and light-evoked [K+]o decrease in the subretinal space. Intravenous SI (30 mg/kg) also showed the suppression of intraretinal b waves. SI not only acted as a poison to the retinal pigment epithelium but also might block the post-synaptic response.

Effects of sodium iodate on the electroretinogram c-wave in the cat

The c-wave of the vitreal electroretinogram decreased in amplitude and was replaced by a slow, polarity reversed potential following an i.v. infusion of sodium iodate, as first described by Noell. Intraretinal recordings showed that the negative-going c-wave, induced by iodate (30 mg/kg), was composed of reduced slow pIII and trans-epithelial c-wave. The effects of iodate on these components may originate from direct effects on the retinal pigment epithelial cells, namely, a large decrease in the trans-epithelial resistance. Other factors could have contributed to the change in the c-wave amplitude.

Animal histo-blood group ABO genes

Sequences homologous to the human histo-blood group ABO genes are present in the genomic DNA of various mammals. We have PCR-amplified, subcloned, and sequenced a portion of these genes from several species of primates and found high conservation of the nucleotide as well as the deduced amino acid sequences during evolution.

New surgical technique for total-defect aortopulmonary window

A new technique is described to repair aortopulmonary window with total defect in an 8-day-old baby. Because we expected the future growth of aorta, we used the anterior wall of the pulmonary artery as a large flap to reconstruct the posterolateral aortic wall. An equine pericardial patch was used to repair the defect in the pulmonary artery. This is a logically effective method for aortic reconstruction in a neonate with a large aortopulmonary septal defect.

[The effects of potassium concentration in reperfusion solution upon myocardial protection]

The effects of potassium in reperfusion solution (RS) and the influence of sodium on this effect were studied. Experimental time course was as followed: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas Cardioplegic Solution followed by global ischemia for 33 or 35 min at 37.5 degrees C, 15 min early Langendorff reperfusion with several different potassium concentration modified with Krebs Henseleit Bicarbonate Buffer (KHBB) containing 145 mM and 110 mM sodium and 5 min late reperfusion with KHBB, followed by 20 min working perfusion. Potassium in RS possessed bell shaped dose response nature with optimal concentration of 10 mM in the condition of 145 mM sodium but 6 m in the condition of 110 mM in terms of percent recovery of aortic flow. Although higher potassium reperfusion produced less Creatine Kinase leakage.

[The effects of protease inhibitor upon the ischemia-reperfusion injury]

The purpose of the study is to investigate the effects of protease inhibitor (Nafamostat mesilate: NM) upon myocardial protection. Hearts were subjected to 20 min working control perfusion followed by 3 min cardioplegic infusion with the St. Thomas Cardioplegic Solution (ST) contained various concentrations of NM, and global ischemia for 33 min at 37 degrees C (Exp. 1) or 150 min at 20 degrees C (Exp. 2). Hearts were then converted to Langendorff reperfusion (the leakage of Creatine Kinase (CK) and Cathepsin B (Cat-B) ware measured) and 20 min working reperfusion. Various concentrations of NM added during Langendorff reperfusion (Exp. 3). During working perfusion cardiac functions (aortic flow (AoF), coronary flow (CoF), heart rate (HR), aortic pressure (AoP)) were measured, and expressed as the percent recovery of pre-ischemic control value. Post-ischemic recovery of AoF (%AoF) showed the bell-shaped dose-response curve, and the optimal dose was 3 microM (Exp. 1) and 10 microM (Exp. 2) respectively. There was a significant (p < 0.05) increase of %AoF in optimal dose compared with that in controls (64.2 +/- 1.2% vs 52.3 +/- 2.5% in Exp. 1, 68.9 +/- 3.1% vs 54.1 +/- 1.4% in Exp. 2). These increase of functional recovery reflected in the values for CK and Cat-B leakage. The addition of NM in ST reduced CK and Cat-B leakage significantly in the concentration of 5 microM (in Exp. 1) and 10 microM (in Exp. 2) respectively. But the addition of NM in reperfusate did not reduced CK leakage significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Photosensitized formation of 8-hydroxydeoxyguanosine in cellular DNA by riboflavin

Photosensitized formation of 8-hydroxydeoxyguanosine (oh8dG) in DNA by riboflavin has recently been shown in vitro. The present study describes the formation of oh8dG in cellular DNA by photo-irradiation of cultured mammalian cells in the presence of riboflavin. Formation of oh8dG was dependent on the concentration of riboflavin as well as the duration of photoirradiation. These results suggest that photosensitized formation of oh8dG in DNA by riboflavin may be involved in photocarcinogenesis.

Human histo-blood group A2 transferase coded by A2 allele, one of the A subtypes, is characterized by a single base deletion in the coding sequence, which results in an additional domain at the carboxyl terminal

We have identified a possible mutation which characterizes A2 alleles (a minor subtype of A) at the human histo-blood group ABO locus based on polymerase chain reaction (PCR) of genomic DNA, followed by nucleotide sequencing of the amplified fragments. The A2 subtype has a single base deletion near the carboxyl terminal. As a result of frame-shifting, A2 transferase possesses an extra domain. Introduction of this single base deletion into the A1 transferase cDNA expression construct drastically decreased the A transferase activity in DNA-transfected HeLa cells.

Effects of intraocular pressure on pH outside rod photoreceptors in the cat retina

Double-barreled H(+)-selective microelectrodes were used to study the effect of raising intraocular pressure (ocular hypertension) on intraretinal pH in the cat. A surprising alkalinizing response was observed in the subretinal space on the first experimental day in seven of 11 experiments. Of the three retinal regions studied, the alkalinizing response was present in the area centralis and in the adjoining near-discal region, but was absent in the superior temporal periphery. The alkalinizing response was relatively fragile, diminishing and then extinguishing with repetition of episodes of ocular hypertension. It was also never observed on the second experimental day. The alkalinizing response had a relatively low threshold, appearing with 10 mmHg elevations of intraocular pressure, i.e. when the perfusion pressure was still relatively high, but was also present across a wide range of perfusion pressures. It was maximal in amplitude in the most distal portion of the subretinal space and consisted of two components, an 'on' alkalinization during the episode of ocular hypertension, and an 'off' alkalinization following it. When the alkalinizing response was present in the subretinal space, it also could be recorded with placement of the microelectrode in the choroid. Elevations of systemic arterial blood pressure with epinephrine (intravenous), by raising perfusion pressure, also alkalinized the subretinal space, indicating that an increase in choroidal blood flow can produce this type of pH response. While pH recordings do not directly monitor blood flow, we tentatively interpreted the alkalinizing response with ocular hypertension as originating from a regional increase in choroidal blood flow, but we cannot rule out other explanations. Acidification of the subretinal space in response to ocular hypertension replaced the alkalinizing response when the latter extinguished, or acidification was the sole response in the absence of an alkalinization. The acidification also had a low threshold, was maximal in the most distal portion of the subretinal space, and increased in size with decreases in perfusion pressure. The acidification was reduced in amplitude by breathing 100% oxygen (hyperoxia). This was interpreted as suppression of the component of acidification that originated from an increase in glycolysis by the rod photoreceptors during ocular hypertension.

A useful cholesterol solvent for medical dissolution of gallstones

Dissolution of cholesterol gallstones by direct instillation of an agent into the biliary tract has been considered an alternate to surgical procedures. We developed an excellent direct solubilizer by combining d-limonene and medium-chain monoglyceride. This mixture enhances the advantages of each individual solvent and minimizes the disadvantages. In vitro experiments were done to determine the viscosities and the cholesterol dissolving rates of various combinations, and in vivo experiments were conducted to study their irritation effects on tissues. The optimal combination was a 3:2 mixture of d-limonene and medium-chain monoglyceride. It could quickly dissolve cholesterol gallstones with minimal or no observable side effect.

Gallbladder mucosal function: studies in absorption and secretion in humans and in dog gallbladder epithelium

The gallbladder is conventionally regarded as an absorptive organ such that dilute hepatic bile is both stored and concentrated. We studied 35 patients who had recovered from a percutaneous transhepatic gallbladder drainage performed for acute cholecystitis. After an overnight fast, gallbladder bile was dark brown in color and had a wide scatter in the lipid composition. Two hours after a meal, the gallbladder bile was opalescent white in color and had the composition of an extracellular fluid. This phenomenon was uniformly observed in all 35 patients and was also consistently reproducible when five patients were repeatedly studied. We used normal dog gallbladder epithelial cell monolayers grown in culture and examined sodium flux. Control gallbladder cells absorbed sodium. When secretin (0.5-2.5 x 10(-7) M) was added, there was a prompt reversal of sodium flux, resulting in net secretion. We conclude that secretion is a physiological function of the gallbladder mucosa. After feeding, the neural and humoral factors divert stored and newly secreted bile into the duodenum and induce active de novo secretion thus producing a gallbladder bile that is opalescent white with no lipids. Our results also have important implications on the origin of the pathological "white bile," the pathogenesis and treatment of gallbladder sludge, as well as the kinetic analysis of compounds undergoing enterohepatic recirculation.

[Biventricular repair for right isomerism associated with transposition of great arteries and common atrioventricular canal]

A 5-years old boy, whose thoracic situs was right isomerism, was diagnosed as transposition of great arteries, common atrioventricular canal (intermediate type), severe tricuspid valve regurgitation, pulmonary valve stenosis, bilateral superior vena cava and left sided inferior vena cava. The preoperative RVEDV was 95% and LVEDV 160%, and LV/RV pressure ratio was 0.54. Atrial rerouting using pericardial patch, replacement of tricuspid valve and pulmonary valvotomy were performed. Postoperative course was uneventful. This was a rare case of right isomerism who received biventricular repair.