Mechanisms of retinoid resistance in leukemic cells: possible role of cytochrome P450 and P-glycoprotein

Retinoic acid (RA) regulates the differentiation and proliferation of a wide variety of different cell types and all-trans RA induces complete remission in a high proportion of patients with acute promyelocytic leukemia (APL). However, clinical resistance to retinoids may develop and poses a serious problem for differentiation-inducing therapy. We studied the effects of RA in combination with a cytochrome P450 inhibitor (clotrimazole) and a P-glycoprotein antagonist (verapamil) on cell growth and differentiation of RA-resistant HL-60 cells and fresh RA-resistant leukemic cells from two APL patients. RA-resistant HL-60 cells and APL cells differentiated to mature granulocytes when cultured with all-trans RA and either clotrimazole and verapamil but not with either of the agents alone. These findings were confirmed in these cells by their increased expression of CD11b antigen and migration-inhibitory factor-related protein-8/14 mRNAs and decreased levels of c-myc mRNA. These combinations also markedly decreased the number of viable cells and inhibited cellular proliferation. After isolation of microsomes, measurements showed that levels of cytochrome P450 activities in both wild-type and RA-resistant HL-60 cells were almost comparable. Moreover, expression of the CYP1A1-type cytochrome P450 gene could not be detected in either cell type. However, RA-resistant HL-60 cells and APL cells, but not RA-sensitive HL-60 cells and APL cells, expressed multidrug-resistance-1 gene transcripts. Taken together, acquired resistance to RA may be explained in part by drug metabolism in leukemic cells. Possible mechanisms for accelerated clearance of RA include the induction of non-CYP1A1 cytochrome P450 enzymes and P-glycoprotein.

[Depression of cellular immunity after aortic arch replacement]

Multiple organ failure due to infection is now one of the most serious postoperative complications following aortic arch replacement. We therefore evaluated the postoperative changes of cellular immunity using four parameters, 1) peripheral lymphocyte subsets 2) mitogen responsiveness 3) the activity of natural killer (NK) cells 4) interleukin-2 (IL-2) production. Patients were divided into two groups: group A (n = 5) with aortic arch replacement and group B (n = 10) with coronary artery bypass grafting. All variables were measured the day before, the day after, 3 days after, 7 days after, and 14 days after surgery. CD3 positive cells in group A were significantly lower than in group B throughout the postoperative course. CD4 positive cells in group A were significantly lower than in group B on the day after 3 days after the operation. IL-2 production in group A was markedly depressed the day after (all patients 0.8 U) and 3 days after (1.5 +/- 1.6 U) as compared to the preoperative level (7.7 +/- 4.4 U) and the levels on the same days in group B. The activity of NK cells in group A was significantly impaired the day after (10.6 +/- 6.7%) and 3 days after (10.0 +/- 6.7%) as compared to the preoperative level (28.6 +/- 16.7%) and the levels on the same days in group B. IL-2 production in group A was significantly correlated to CD3 and CD4 positive lymphocyte levels. These results clearly showed that patients who underwent aortic arch surgery suffered functional depression of cellular immunity, in particular IL-2 production and the activity of NK cells. These depressions may be a result of massive blood transfusion, tissue trauma under hypothermic cardiopulmonary bypass.

A case of primary glucocorticoid resistance

A 79-year-old woman developed hypokalemia and metabolic alkalosis after breast cancer surgery. She was suspected of having primary glucocorticoid resistance on the basis of high plasma ACTH and serum cortisol levels without the features of Cushing's syndrome. To clarify the end-organ resistance to cortisol, we characterized the glucocorticoid receptors (GR) in cultured skin fibroblasts from the patient. The GRs in whole cell assays decreased binding affinity (Kd = 11.1 +/- 0.6 nM) and the number of binding sites for [3H]dexamethasone (binding capacity was 15,600 +/- 1,255 sites per cell). These results strongly suggest that our patient had primary glucocorticoid resistance caused both by a decreased number of GRs and a reduction in the affinity of GRs to cortisol.

Histamine N-methyltransferase inhibitor potentiates histamine- and antigen-induced airway microvascular leakage in guinea pigs

BACKGROUND

Histamine N-methyltransferase (HMT) modulates histamine- and antigen-induced bronchoconstriction. However, it is unclear whether vascular permeability evoked by an allergic reaction can be exaggerated by inhibition of HMT activity.

METHODS

We studied the effects of intravenously injected SKF 91488, a specific HMT inhibitor, on increases in plasma extravasation induced by intravenously injected histamine in unsensitized guinea pigs and by intravenously injected ovalbumin antigen in guinea pigs sensitized to ovalbumin in vivo with Evans blue dye as a marker.

RESULTS

Pretreatment with SKF 91488 shifted, in a dose-dependent fashion, the dose-response curves of the leakage of dye to histamine to lower concentrations in the trachea, main bronchi, and nasal mucosa. Likewise, pretreatment with SKF 91488 (20 mg/kg intravenously) significantly increased the leakage of dye induced by ovalbumin antigen (200 micrograms/kg intravenously) in three parts of the airway (p < 0.05). In contrast to SKF 91488, intravenously injected aminoguanidine, a specific inhibitor of diamine oxidase (16 mg/kg intravenously), did not alter the leakage of dye induced by histamine (from 0.001 microgram/kg to 10 micrograms/kg intravenously) (p < 0.20). HMT activities were observed in the nasal mucosa, as well as in the trachea and main bronchi, as shown in a previous study.

CONCLUSION

These findings suggest that HMT modulates the effects of exogenous histamine and endogenously released histamine induced by antigen challenge on plasma extravasation in the airway in guinea pigs in vivo.

Phosphorylation of HS1, GAP-associated p190 and a novel GAP-associated p60 protein by cross-linking of Fc gamma RIIIA

Human Fc gamma receptor IIIA (hFc gamma RIIIA) cDNA was introduced into mouse macrophage/monocyte cell line P388D1, and several stable cell clones expressing hFc gamma RIIIA were isolated. This facilitated the study of the biological function of Fc gamma RIIIA in monocytes/macrophages. The cloned cells showed the high phagocytic activity mediated by hFc gamma-RIIIA, while the original P388D1 cells did not. In order to examine the phosphorylation of proteins involved in hFc gamma RIIIA signal transduction, these receptors were stimulated by cross-linking. The cross-linking of hFc gamma RIIIA induced a rapid increase in tyrosine phosphorylation of several proteins, including PLC-gamma 1, Syk, HS1, and p21rasGAP-associated p190 and p60 proteins. Immunoblotting with a polyclonal antibody specific for the GAP-associated p62 protein, which was originally found in fibroblasts and is homologous with an RNA-binding protein, revealed that the p60 phosphorylated after cross-linking of hFc gamma RIIIA seemed to represent a novel GAP-associated protein unrelated to the known GAP-associated p62 protein, which was also present in the P388D1 cells.

An abnormally acidic TATA-binding protein from a hyperthermophilic archaeon

The gene encoding the TATA-binding protein (PkTBP) from a hyperthermophilic archaeon, Pyrococcus sp. KOD1 (Pk), was cloned and sequenced. An open reading frame with homology to the conserved C-terminal core region of eukaryotic TBP was expressed in Escherichia coli. Specific DNA-binding activity of the recombinant PkTBP (190 amino acids, 21.36 kDa) was also demonstrated. Although it was composed of a structurally direct repeat sequence which is similar to eukaryotic TBP, the total net charge of archaeal TBP was amazingly negative (calculated isoelectric point (pI) was 4.66 and experimentally estimated pI was 4.8). A series of five Glu residues was found at the C terminus of archaeal TBP. These data strongly suggest that a positively charged protein is also involved in the transcription initiation event which might stabilize the structure of the genomic DNA under high-growth-temperature conditions.

Osteochondroma of the cervical spine. MR findings

We report two cases of osteochondroma in the region of the cervical spine. The magnetic resonance (MR) images well demonstrated the relationship of the tumor, the spinal cord, and adjacent soft tissue, but correct diagnosis by MR imaging was difficult in one patient due to unusual gadolinium enhancement. Computed tomography played an important role in these patients by demonstrating the exact origin and nature of the tumor.

Quantitative assessment of daily physical activity levels in patients with chronic heart failure by measuring energy expenditure--effects of converting enzyme inhibitor therapy

Although a major goal in the treatment of chronic heart failure is to improve daily physical activity levels, this has not been assessed quantitatively. An increased daily activity level may be reflected by an increase in daily energy expenditure. In the present study, measurements of energy expenditure with a commercially available ambulatory calorimeter were first validated using cardio-pulmonary exercise tests in 5 normal volunteers. The energy expenditure measured by the calorimeter correlated well with that estimated from oxygen uptake (r = 0.89). Subsequently, the daily energy expenditure was serially measured with the calorimeter during long-term administration of the converting enzyme inhibitor ramipril for 24 weeks in 8 patients with chronic heart failure. Changes in echocardiographic parameters and exercise capacity were also studied. Peak oxygen uptake and anaerobic threshold assessed with symptom-limited maximal bicycle exercise were significantly increased 12 weeks or more after the initiation of treatment (P < 0.01 and P < 0.01, respectively). Left ventricular fractional shortening substantially, but not significantly, increased during this period (P < 0.1). These results strongly suggest that an overall improvement in heart failure was achieved after long-term ramipril therapy. The energy expenditure during daily activities was also significantly increased after ramipril therapy for 24 weeks (P < 0.01). Thus, the daily energy expenditure increased with improvement of heart failure, probably reflecting an increase in daily activity levels. We conclude that calorimetric measurement of daily energy expenditure is a novel and simple technique for quantitative evaluation of the effect of therapy on daily physical activity levels in patients with chronic heart failure.

Homooligopeptides composed of hydrophobic amino acid residues interact in a specific manner by taking alpha-helix or beta-structure toward lipid bilayers

In order to investigate the role of each amino acid residue in determining the secondary structure of the transmembrane segment of membrane proteins in a lipid bilayer, we made a conformational analysis by CD for lipid-soluble homooligopeptides, benzyloxycarbonyl-(Z-)Aaan-OEt (n = 5 - 7), composed of Ala, Leu, Val, and Phe, in three media of trifluoroethanol, sodium dodecyl sulfate micelle, and phospholipid liposomes. The lipid-peptide interaction was also studied through the observation of bilayer phase transition by differential scanning calorimetry (DSC). The CD studies showed that peptides except for Phe oligomers are present as a mainly random structure in trifluoroethanol, as a mixture of alpha-helix, beta-sheet, beta-turn, and/or random in micelles above the critical micellization concentration and preferably as an extended structure of alpha-helical or beta-structure in dipalmitoyl-D,L-alpha-phosphatidylcholine (DPPC) liposomes of gel state. That the beta-structural content of Val oligomers in lipid bilayers is much higher than that in micelles and the oligopeptides of Leu (n = 7) and Ala (n = 6) can take an alpha-helical structure with one to two turns in lipid bilayers despite their short chain lengths indicates that lipid bilayers can stabilize the extended structures of both alpha-helical and beta-structures of the peptides. The DSC study for bilayer phase transition of DPPC/peptide mixtures showed that the Leu oligomer virtually affects neither the temperature nor the enthalpy of the transition, while Val and Ala oligomers slightly reduce the transition enthalpy without altering the transition temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancing and inhibitory effects of nitric oxide on superoxide anion generation in human polymorphonuclear leukocytes

1. The effects of sodium nitroprusside (SNP, a nitric oxide donor) and authentic nitric oxide (NO) on superoxide anion (O2-) generation were investigated in human polymorphonuclear leukocytes (PMNs). 2. Neither SNP (10 nM to 10 microM) nor NO (40 nM to 40 microM) alone induced O2- generation or change of intracellular Ca2+ concentration ([Ca2+]i) in human PMNs. 3. Pretreatment with SNP or NO at the concentrations used (SNP, 10 nM to 10 microM: NO, 40 nM to 40 microM) showed a biphasic concentration-dependent effect on O2- generation induced by f-methionyl-leucyl-phenylalanine (FMLP). Low concentrations of SNP (10 nM to 100 nM) and NO (400 nM) did not affect either basal cyclic GMP levels or cyclic GMP levels stimulated by FMLP, but enhanced FMLP-induced O2- generation and [Ca2+]i elevation. On the other hand, high concentrations of SNP (10 microM) and NO (40 microM) alone elevated cyclic GMP levels and inhibited FMLP-induced O2- generation and [Ca2+]i elevation. 4. 8-Bromo-cyclic GMP (8-Br-cyclic GMP) at concentrations ranging from 1 microM to 1 mM did not induce O2- generation on its own and had little effect on FMLP-induced O2- generation and [Ca2+]i elevation. 5. Addition of a high concentration of NO (40 microM) decreased authentic O2- formation by pyrogallol in a cell-free system, but a low concentration of NO (400 nM) had no effect on this. On the other hand, addition of SNP in the concentration-ranges used had no effect on authentic O2- formation by pyrogallol. 6. In this study, we have shown that SNP and NO have dual effects (enhancement and inhibition) on 02- generation induced by FMLP in human peripheral PMNs. The results suggest that the enhancement observed with SNP and NO at low concentrations is not mediated by activation of the guanylate cyclase-cyclic GMP pathway. The suppressive effect of SNP and NO at higher concentrations is mediated by the NO-induced O2--scavenging effect and activation of the guanylate cyclase-cyclic GMP pathway.

Activity of artificial mutant variants of human growth hormone changes in charged residues around 62-67

Our previous work has shown that the amino acid residues around 62-67 located in the connecting loop between helix I and II of human growth hormone (hGH) are important in eliciting the differentiation of preadipose 3T3-F442A cells to adipocytes. In this study, we evaluated the role of the charged residues around 62-67 in receptor binding and biological activity. Eight artificial mutant variants of hGH were prepared in Escherichia coli by site-directed mutagenesis. Replacement of Arg64 with Tyr (R64Y variant) resulted in a significant loss of binding to the somatogenic receptors on 3T3-F442A cells, but retained full adipose conversion activity on these cells. Replacement of Arg64 with Glu (R64E) produced a considerable loss in receptor binding and a significant loss in biological activity. hGH variants in which either Glu65 or Glu66 was replaced with Asp (E65D and E66D) and with Gln (E65Q and E66Q) showed a slight loss in binding activity and retained almost a full adipogenic activity. An E65P variant (replacement of Glu65 with Pro) possessed the same binding activity as hGH, although it failed to induce full biological activity. The insertion of Ala between Asn63 and Arg64 (63NAR) caused a marked loss in both activities. These results indicate that the positively charged Arg64 is important for receptor binding and thereby in eliciting the biological activity of hGH, while negatively charged Glu65 and Glu66 are less important. In addition, our findings confirm that the conformation and size of the loop region around Arg64 is important for the adipose conversion activity of hGH.

Potentiating effect of nicorandil, an antianginal agent, on relaxation induced by isoproterenol in isolated rat aorta: involvement of cyclic GMP-inhibitable cyclic AMP phosphodiesterase

In rat aortic rings, isoproterenol (ISO) 10(-9)-3 x 10(-6)M relaxed the contraction induced by phenylephrine (PE) 3 x 10(-7)M. Pretreatment with nicorandil 3 x 10(-7) and 3 x 10(-6) M potentiated the relaxation induced by ISO. Nicorandil 3 x 10(-6) M also potentiated the relaxations induced by forskolin 3 x 10(-9) - 10(-6) M and dibutylyl-cyclic AMP 3 x 10(-6) - 3 x 10(-4) M. Nitroglycerin (NTG) 10(-8) M, but not cromakalim 3 x 10(-8) M, also potentiated the ISO relaxation. Pretreatment with glyburide 10(-6) M or apamin 10(-6) M did not affect the potentiating action of nicorandil 3 x 10(-6) M. Pretreatment with methylene blue (MB) 10(-6) M, but not with NG-monomethyl-L-arginine (NMMA), however, markedly inhibited the potentiating effect of nicorandil. Removal of endothelium impaired the relaxation induced by ISO but did not inhibit the potentiating effect of nicorandil. In addition, in the presence of MCl-154 (10(-7) M), which itself potentiated ISO-induced relaxation, nicorandil 3 x 10(-6) M did not further potentiate the relaxing response to ISO. Furthermore, nicorandil 3 x 10(-6) M potentiated the increase in the tissue level of cyclic AMP caused by ISO 3 x 10(-7) M, whereas the nicorandil-induced increase in cyclic GMP levels were not affected by ISO. These results suggest that the potentiating effect of nicorandil on the relaxation induced by ISO is most likely due to inhibition of phosphodiesterase III (PDE III) by increased cyclic GMP levels.

Posterior fossa glioblastoma multiforme: MR findings

PURPOSE

To characterize the MR findings of glioblastoma multiforme in the posterior fossa.

METHODS

MR studies of nine patients with surgically proved posterior fossa glioblastoma multiforme were retrospectively evaluated. MR characteristics studied included tumor location, signal intensity, enhancement pattern, and presence of intratumoral hemorrhage, as well as presence of secondary hydrocephalus or metastatic spread.

RESULTS

The tumors were located in the median portion of the cerebellum or brain stem in eight cases. Six extended into the fourth ventricle. Hydrocephalus was seen in four cases. Six cases demonstrated decreased T1- and increased T2-weighted signal intensities. Three cases demonstrated mixed signal intensities suggesting intratumoral hemorrhage. All of the eight patients who received contrast showed moderate to marked heterogeneous ringlike enhancement suggesting intratumoral necrosis. Multicentric/multifocal lesions or extraaxial metastases were identified in three of the nine cases, and there was extracranial extension into the cervical region in one case.

CONCLUSION

Glioblastoma multiforme is a rare tumor in the posterior fossa. Differentiating it from metastatic tumor or malignant astrocytoma was difficult. However, combination of heterogeneous and ringlike enhancement, midline location, poorly defined margin, tumoral hemorrhage, concomitant multicentric/multifocal lesions, and extraaxial or extracranial metastasis may be clues for the prospective diagnosis of glioblastoma multiforme.

CT finding of transient focal increased attenuation of the liver adjacent to the gallbladder in acute cholecystitis

OBJECTIVE

The purpose of this article is to report the finding of transient focal increased attenuation of the liver adjacent to the gallbladder on enhanced CT scans in patients with acute cholecystitis. This finding should not be confused with primary liver abnormalities.

MATERIALS AND METHODS

Five patients with acute cholecystitis were studied. Because a thickened gallbladder wall was seen on sonography, all patients were examined preoperatively with incremental dynamic helical CT to exclude carcinoma of the gallbladder. CT findings were compared with results of sonography for five patients, MR imaging for two patients, and surgery for five patients.

RESULTS

Transient focal increased attenuation of the liver adjacent to the gallbladder was seen in the early phase of incremental dynamic CT in five patients and extended into the medial segment anterior to the porta hepatis. The areas showing increased attenuation adjacent to the gallbladder had a curvilinear shape around the gallbladder. No hepatic masses were seen on sonograms, on MR images, or at surgery.

CONCLUSION

Transient focal increased attenuation of the liver may occur on CT scans in patients with acute cholecystitis. The increased attenuation associated with acute cholecystitis has a typical location and pattern. This finding is probably attributable to hepatic arterial hyperemia and to early venous drainage caused by the adjacent inflamed gallbladder. This finding should be differentiated from hypervascular hepatic tumors.

[A case of psychological non-neuropathic bladder successfully diagnosed by continuous monitoring of detrusor pressure]

We report a case of psychological non-neuropathic bladder difficult to diagnose and treat. A 44-year-old woman was admitted to the Department of Urology of the Asahikawa Medical College Hospital with complaints of difficulty in micturition and urinary incontinence. Urodynamic studies revealed underactive function of the detrusor and incompetent urethra. She was instructed in self intermittent catheterization for difficulty in micturition. Drug therapy, electrical stimulation and vesicourethral suspension were not effective to control urinary incontinence. Since uninhibited detrusor contraction was elicited by psychogenic stress during continuous monitoring of the detrusor function, she was diagnosed as psychological non-neuropathic bladder closely related to psychogenic factor. She had a careful counselling and medical treatment designed by her psychiatrist, urinary incontinence was remitted in about one year and a half.

Oxidants affect permeability and repair of the cultured human tracheal epithelium

To examine the effects of oxidants on the airway epithelial barrier functions, human tracheal epithelial cells were cultured on porous filter membrane. Glucose oxidase (GO; 10 U/ml), hydrogen peroxide (H2O2; 4 x 10(-3) M), and xanthine (5 x 10(-4) M) plus xanthine oxidase (20 mU/ml) (X-XO) significantly increased electrical conductance across epithelial membrane (G), short-circuit current (Isc) measured with Ussing's chamber methods, and [3H]mannitol flux through the cultured epithelium. Increases in G and Isc induced by oxidants were significantly inhibited by catalase (1,000 U/ml) and the protein kinase C inhibitor staurosporine (10(-7) M), but superoxide dismutase (SOD; 100 U/ml) was without effect. GO, H2O2, and X-XO inhibited the epithelial cell growth, [3H]thymidine incorporation by the cells, and epithelial repair of artificially produced focal epithelial defects (1-2 mm diam) on plastic vessels. Catalase also inhibited effects induced by oxidants on cell growth and proliferation. These results suggest that oxidants reduce tracheal epithelial barrier functions by damaging tight junctions and inhibiting cell proliferation, and these effects of oxidants on epithelial cells may be mediated by H2O2 rather than superoxide anion and by activation of protein kinase C.

Acute or chronic exercise alters angiotensin II-induced contraction of rat aorta

Chronic exercise substantially shifted the dose-response curve for angiotensin II (ANG II)-induced contractions to the right with increases in the EC50 value in both endothelium-intact and endothelium-denuded aortae. An acute endurance exercise also caused a 3-fold increase in the EC50 value in both endothelium-intact and endothelium-denuded aortae from sedentary control rats. Whereas, no substantial increase in the EC50 value was observed in trained rats after an acute endurance exercise. Thus, chronic exercise attenuates ANG II receptor-mediated contraction of rat aortae. An acute exercise also caused the reduced responses to ANG II in sedentary control rats but not in chronically exercise-trained rats.

Multiple intrahepatic aneurysms following transcatheter arterial embolization. Work in progress

PURPOSE

To discuss the mechanism of multiple intrahepatic aneurysm formation after transcatheter arterial embolization (TAE) performed in five patients with hepatocellular carcinoma.

MATERIALS AND METHODS

TAE was performed with gelatin sponge particles and iodized oil as embolic materials. Mitomycin C was also used in four cases.

RESULTS

Three to 14 aneurysms 1-6 mm in diameter were found in third-to sixth-order branches of the hepatic arteries at repeat angiography performed 25-45 days after TAE. Follow-up angiograms in three cases revealed that most aneurysms were no longer apparent except in one patient in whom two aneurysms remained and were larger than before. In none of the five cases were any signs of aneurysm rupture noted.

CONCLUSION

Radiologists should be aware of this complication of TAE. It is speculated that the main cause of aneurysm formation in these patients was the embolic agents used.

Purification and characterization of a thermostable thiol protease from a newly isolated hyperthermophilic Pyrococcus sp

A hyperthermophilic archaeon strain, KOD1, was isolated from a solfatara at a wharf on Kodakara Island, Kagoshima, Japan. The growth temperature of the strain ranged from 65 to 100 degrees C, and the optimal temperature was 95 degrees C. The anaerobic strain was an S0-dependent heterotroph. Cells were irregular cocci and were highly motile with several polar flagella. The membrane lipid was of the ether type, and the GC content of the DNA was estimated to be 38 mol%. The 16S rRNA sequence was 95% homologous to that of Pyrococcus abyssi. The optimum growth pH and NaCl concentration of the strain KOD1 were 7.0 and 3%, respectively. Therefore, strain KOD1 was identified as a Pyrococcus sp. Strain KOD1 produced at least three extracellular proteases. One of the most thermostable proteases was purified 21-fold, and the molecular size was determined to be 44 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 45 kDa by gel filtration chromatography. The specific activity of the purified protease was 2,160 U/mg of protein. The enzyme exhibited its maximum activity at approximately pH 7.0 and at a temperature of 110 degrees with azocasein as a substrate. The enzyme activity was completely retained after heat treatment at 90 degrees C for 2 h, and the half-life of enzymatic activity at 100 degrees C was 60 min. The proteolytic activity was significantly inhibited by p-chloromercuribenzoic acid or E-64 but not by EDTA or phenylmethylsulfonyl fluoride. Proteolytic activity was enhanced threefold in the presence of 8 mM cysteine. These experimental results indicated that the enzyme was a thermostable thiol protease.

[A successful surgical treatment for type IA cor triatriatum with an unroofed coronary sinus]

The combination of type IA cor triatriatum (Lucas-Schmidt's classification) and unroofed coronary sinus is very rare in congenital heart diseases. We have presented the first successful surgical treatment for an infant who had this combination. The patient was 10-month-old infant who admitted with cardiac murmur and short stature. Echocardiography revealed that an abnormal septum in the left atrium and dilated coronary sinus. Under cardiopulmonary bypass she underwent surgical treatment which consisted of a resection of the intra-left-atrial diaphragma, closure of ASD with an equine pericardial patch. During operation, unroofed coronary sinus (partially unroofed terminal portion of the coronary sinus) was revealed. Her postoperative course was uneventful.