Thoracoscopic Esophagectomy for a Patient With Perforated Esophageal Epiphrenic Diverticulum After Kidney Transplantation: A Case Report.

A 58-year-old man who underwent cadaveric kidney transplantation twice presented to hospital with a perforated epiphrenic diverticulum. Computed tomography revealed epiphrenic diverticulitis and right pleural effusion. Upper gastrointestinal fibroscopy showed an epiphrenic diverticulum full of food residue. He was transferred to our hospital, where we performed percutaneous endoscopic gastrostomy under general anesthesia in the supine position before thoracoscopy. Thoracoscopic esophagectomy was performed in the semi-prone position under 6-10 mmHg artificial pneumothorax via the right thoracic cavity. We performed subtotal esophagectomy to remove sources of infection because the esophageal wall surrounding the diverticulum was too thick to close or to perform diverticulectomy. A cervical esophagostomy was constructed after the thoracic procedure. The patient was managed with continuous hemodiafiltration and administered immunosuppressants and steroids to preserve the transplanted kidney. Continuous hemodiafiltration was stopped on postoperative day (POD) 4. The patient was discharged from the intensive care unit on POD 10 and transferred to the original hospital on POD 24 for rehabilitation. The second operative stage was performed on POD 157 at our hospital. We performed gastric tube reconstruction via the ante-sternal route and anastomosed the tube to the cervical esophagus. The postoperative course was uneventful; the patient was transferred to the original hospital on POD 15 after the second operation. Minimally invasive surgery was sufficient to treat perforated epiphrenic diverticulum while preserving the transplanted kidney. We recommend completely removing the source of infection and reducing surgical invasiveness to preserve the transplanted kidney in cases of esophageal perforation following kidney transplantation.

Indocyanine green angiography for intra-operative assessment in vascular surgery.

OBJECTIVES: Indocyanine green (ICG) angiography is used for the intra-operative assessment of the graft vessel in coronary artery bypass grafting to enable immediate revision if necessary. We report the feasibility and implications of an ICG colour imaging system, HyperEye Medical System (HEMS), in surgeries for arteriosclerosis obliterans (ASO) and abdominal aortic aneurysm (AAA) which carry risk of mesenteric ischaemia. METHODS: HEMS ICG angiography was used for the intra-operative assessment of 12 ASO patients and 10 AAA patients. RESULTS: In the ASO patients, HEMS angiography enabled visualisation of the graft and native artery. The fluorescent lucent region in the artery distal to the anastomosis was shown in 1 of 12 ASO patients. There was a 3-s time lag in the increase of intensity between the proximal artery and distal stenotic region. In AAA patients, HEMS angiography clearly showed the perfusion in the mesenteric arteries and intestinal wall as opaque. One AAA patient had segmental ischaemia due to thromboembolism and another one had diffuse ischaemia due to systemic malperfusion. The ischaemic region of the intestine was visualised as a fluorescent lucent area by HEMS angiography. CONCLUSION: HEMS angiography can accurately assess peripheral arterial perfusion in surgical cases with ASO and AAA.

Sentinel node microscopic metastasis detected after segmentectomy for lung cancer followed by completion lobectomy: two case reports.

We performed sentinel node identification using radioisotopic and/or dye techniques to determine the final indication after segmentectomy in cases with non-small cell lung cancer. Sentinel nodes were examined using intraoperative frozen sections stained with hematoxylin and eosin. We present 2 cases with completion lobectomy performed 7 and 11 days after segmentectomy because immunohistochemical staining of the sentinel nodes showed the presence of microscopic metastases that were not detected by the examination of intraoperative frozen sections.

Frequent overexpression of epidermal growth factor receptor (EGFR) in mammary high grade ductal carcinomas with myoepithelial differentiation.

AIMS: To evaluate the expression of common biological markers and the epidermal growth factor receptor (EGFR) in mammary high grade ductal carcinomas with myoepithelial differentiation (DCMDs). MATERIALS/METHODS: Thirty DCMDs were clinicopathologically and immunohistochemically analysed and compared with 36 control cases of high grade conventional invasive ductal carcinoma (IDC). RESULTS: EGFR, HER2/neu, oestrogen receptor, progesterone receptor, and p53 expression was seen in 21, one, three, four, and 20 of the 30 DCMDs, compared with eight, nine, 18, 17, and five of the 36 conventional IDCs (p<0.05), respectively. In 16 of the 30 DCMDs, metastases were found in the brain, lung, bone, and liver, within a maximum of 47 months (mean, 13.9) after initial surgery, whereas only four of the 36 conventional IDCs metastasised to the lung and bone within a maximum of 27 months (mean, 18.0) after initial surgery (p=0.0001). There was a significant difference in disease free survival between DCMD and conventional IDC (p=0.001). EGFR was frequently overexpressed in DCMD compared with conventional IDC, whereas the expression of HER2/neu and hormone receptors was lower in DCMD. Fluorescent in situ hybridisation revealed that the mean EGFR to chromosome 7 centromere (CEP7) ratio of the 24 DCMD cases available for evaluation was 1.03, and EGFR gene amplification was not detected in the 21 DCMD cases with EGFR overexpression. CONCLUSION: Immunohistochemistry for myoepithelial markers and EGFR is useful for the accurate diagnosis and molecular target treatment of high grade DCMD.

The emergence in Japan of Sathuperi virus, a tropical Simbu serogroup virus of the genus Orthobunyavirus.

In 1999, two viruses were isolated from blood samples of sentinel cattle in the Western part of Japan. The physiochemical and morphological properties of these viruses indicated that they belonged to the family Bunyaviridae. Sequence analysis of the S segment indicates that the two viruses are closely related to Sathuperi virus (SATV). The N-terminal 168 amino acid of the G2 protein of the M segment was highly homologous with that of SATV (98.2%). Given these results, we conclude that the newly isolated viruses are closest to SATV, which was initially isolated in India and Nigeria over 30 years ago.

High insulin enhances neutrophil transendothelial migration through increasing surface expression of platelet endothelial cell adhesion molecule-1 via activation of mitogen activated protein kinase.

AIMS/HYPOTHESIS: There is increasing evidence that hyperinsulinaemia is linked with the development of atherosclerosis in patients with diabetes. However, the mechanisms by which hyperinsulinaemia causes accelerated atherosclerosis, especially with respect to leukocytes transendothelial migration, are poorly understood. We examined whether hyperinsulinaemia directly affects neutrophil transendothelial migration and surface expression of related endothelial adhesion molecules. METHODS: Experiments on the transmigration of neutrophils from healthy volunteers and from patients with Type II (non-insulin-dependent) diabetes mellitus across human umbilical vein endothelial cells cultured in insulin-rich medium using cell-culture inserts were carried out. Migrated neutrophils were quantified by measuring their myeloperoxidase activities, and the surface expression of endothelial adhesion molecules was examined using an enzyme immunoassay. RESULTS: High insulin (over 50 microU/ml for 24 h) enhanced neutrophil transendothelial migration in a dose-dependent manner. This was associated with increased expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) but not of intercellular adhesion molecule-1 (ICAM-1), P-selectin or E-selectin. Both phenomena were attenuated by pretreatment with a tyrosine kinase inhibitor, especially a mitogen-activated protein kinase inhibitor, but not by inhibitors of other second messengers. In addition, a mitogen-activated protein kinase activator, anisomycin, by itself enhanced both neutrophil transendothelial migration and PECAM-1 expression within 3 h in a dose-dependent manner. Pretreatment with nitric oxide synthase inhibitors had no effect on these events. CONCLUSION/INTERPRETATION: These results suggest that hyperinsulinaemia could accelerate atherosclerosis by directly enhancing neutrophil transendothelial migration through increasing endothelial PECAM-1 expression via mitogen-activated protein kinase activation.

High insulin exacerbates neutrophil-endothelial cell adhesion through endothelial surface expression of intercellular adhesion molecule-1 via activation of protein kinase C and mitogen-activated protein kinase.

AIMS/HYPOTHESIS: The association of insulin resistance and compensatory hyperinsulinaemia with increased coronary events in diabetic patients is poorly understood. There are few publications about the direct atherogenic actions of insulin on the endothelium compared with those on vascular smooth muscle cells. The aim of this study was to elucidate whether high insulin directly affects neutrophil-endothelial cell adhesion and surface expression of endothelial adhesion molecules. We also examined what intracellular mechanisms are involved in these events. METHODS: Studies of adhesion between neutrophils from healthy volunteers and human umbilical vein endothelial cells incubated in insulin-rich medium were carried out. Adhered neutrophils were quantified by measuring their myeloperoxidase activities and surface expression of endothelial adhesion molecules was examined using an enzyme immunoassay. RESULTS: High insulin enhanced neutrophil-endothelial cell adhesion with an increase in the expression of intercellular adhesion molecule-1 but not E-selectin or P-selectin. Both phenomena were attenuated by pretreatment with protein kinase C inhibitors and a mitogen activated protein kinase inhibitor. CONCLUSIONS/INTERPRETATION: These results suggest that hyperinsulinaemia causes vascular injury by directly exacerbating neutrophil-endothelial cell adhesion through increasing endothelial expression of intercellular adhesion molecule-1 via activation of protein kinase and mitogen activated protein kinase pathways.

Multicentricity and histopathological background features of familial breast cancers stratified by menopausal status.

BACKGROUND: We investigated histopathological background and multicentricity in patients with familial breast cancers (FBCs) in comparison with these features in patients with sporadic breast cancers (SBCs), stratifying patients by menopausal status. METHODS: We collected a consecutive series of 469 FBC patients and 3334 SBC patients treated at our hospital between 1965 and 1995. The following criteria were used to define FBC, regardless of the presence or absence of a family history of other cancer or the patient's past history of malignancies: (1) Three or more second-degree relatives had been affected by breast cancer; (2) two first-degree relatives had been affected by breast cancer, and either one of them was under 40 years of age and/or had had bilateral breast cancers. The presence or absence of background proliferative lesions (PL; ductal/lobular hyperplasia and/or adenosis) and the multicentricity of breast carcinomas in FBCs and SBCs were analyzed for each group. RESULTS: In premenopausal FBC patients, there was a non-significant trend towards a high frequency of multicentricity compared with findings in patients with SBCs overall (P = 0.087; odds ratio [OR], 1.43; 95% confidence interval [CI], 0.96-2.13). In premenopausal FBC patients, the frequency of background proliferative lesions with/or without fibroadenomas (FA) in the resected specimen was significantly higher than that in SBC patients overall (P = 0.001 for PL; OR, 1.47; 95% CI, 1.18-1.83; P < 0.001 for PL +/- FA; OR, 6.84; 95% CI, 4.93-9.49). With regard to the other clinicopathological factors examined, there were no significant differences between the two groups, except for the higher frequency of premenopausal patients among the FBC patients. CONCLUSION: These results indicate that premenopausal patients with FBCs had more proliferative lesions in the histopathological background and more multicentric breast cancers than premenopausal patients with SBCs.

Association of breast cancer with meningioma: report of a case and review of the literature.

We report a case of meningioma subsequently developed in a patient with primary breast carcinoma. A 53-year-old woman received a left modified radical mastectomy because of stage IIA breast carcinoma. Histologically, the tumor was a predominantly intraductal carcinoma with negative lymph node metastasis. Estrogen receptor (ER) was negative but progesterone receptor (PR) of the left tumor was positive by immunohistochemistry. Four years later, cranial bone and/or brain metastasis was suspected from a routine follow-up bone scintigram. The patient showed no symptoms or signs at that time. Magnetic resonance imaging (MRI) and angiography revealed that the right parasagittal mass was suspicious of meningioma. A complete tumor removal was performed. On histological examination, this brain tumor was a transitional-type meningioma (meningotheliomatous and fibrous type) without malignant findings. ER was negative but PR was positive also in this tumor. She is currently well 6 years after the initial surgery. A review of the literature is presented with emphasis on the association between breast cancer and meningioma, which indicates a possible hormonal relationship. The knowledge of this association is important in the differential diagnosis of patients with breast cancer who develop central nervous manifestations.

Angiographic classification of coronary dissections after plain old balloon angioplasty for prediction of regression at follow-up.

Coronary dissection after plain old balloon angioplasty often shows regression during follow-up. This study sought to determine whether we can predict such phenomenon angiographically. We analyzed 64 patients with 71 type B-D coronary dissections determined by the National, Heart, Lung, and Blood Institute (NHLBI) criteria. Regression was considered present when minimal lumen diameter increased by more than 0.3 mm during follow-up. Dissections were divided into subgroups using the NHLBI criteria and our classification in which type a and b dissections were characterized by the width of a dissection lumen exceeding one quarter of the reference diameter with the outer edge of the dissection lumen within the boundary of reference in type a and beyond it in type b. In type c and type d dissections, the width of the dissection lumen was within one quarter of the reference with its outer edge within the boundary of reference in type c and beyond it in type d. Type e dissection had a protruding flap or spiral appearance. Regression was recognized in 23.9%. The distribution of dissection types was similar in the groups with and without regression by the NHLBI criteria, but type c dissection had regression more frequently than the other types of coronary dissections (p<0.001) using our classification.

Cholesteryl ester transfer protein and atherosclerosis in Japanese subjects: a study based on coronary angiography.

We undertook a cross-sectional analysis on CETP and atherosclerosis among Japanese subjects, by means of CETP mass assay, its gene polymorphism and coronary angiogram. The 110 consecutive patients who underwent coronary angiography were enrolled into the study except for those over 70 years and taking lipid-lowering drugs. Association was analyzed among plasma lipid and lipoproteins, CETP mass, its gene polymorphisms and the finding in coronary angiography. Four CETP-deficiency heterozygotes were identified and excluded from the analysis. CETP mass level showed neither significant correlation with the coronary score (CS) (r=0.06, P=0.52) nor the difference between the groups eventually diagnosed as coronary heart disease (CHD) positive and CHD negative (2.36+/-0.57 vs. 2.24+/-0.21, P=0.24). CETP mass correlated with the total and LDL cholesterol (r=0.43, P<0.001; r=0.36, P<0.001, respectively) but not with HDL cholesterol (r=0.08, P=0.40). While I405V polymorphism had no impact on CETP mass, HDL cholesterol or CS, CETP mass was low with TaqIB polymorphism (B1B1>B2B2, P<0.05) only in the low CS group (<4). Among the lipid and lipoprotein, HDL cholesterol had a greater impact than LDL cholesterol on coronary atherosclerosis. We concluded that CETP mass in plasma does not correlate with coronary atherosclerosis as whole in the non-CETP-deficient. However, the B2B2 genotype in CETP TaqIB polymorphism, only when it decreases the CETP level, may act as a protective factor against atherosclerosis. It should also be noted that CETP mass in general correlates to total and LDL cholesterol, so that it would be an indirect atherogenic parameter.

Diabetic mastopathy: a case report with reference to the findings of enhanced computed tomography.

We report a case of insulin-dependent diabetic fibrous mastopathy with special reference to the findings of computed tomography (CT). The patient was a 27-year-old woman with a history of insulin-dependent diabetes mellitus from childhood who presented with a right breast tumor. Physical examination showed a stony-hard, ill-defined but freely movable mass under the nipple of the right breast without nipple discharge. Mammography revealed a high-density mass shadow without microcalcifications or spicular formation. Ultrasonographic examination revealed an irregularly-shaped hypoechoic lesion with marked posterior acoustical shadowing. Contrast-enhanced CT revealed poor early phase contrast enhancement and slight delayed phase heterogeneous enhancement. Since core needle biopsy revealed fibrocystic disease, the lesion was suspicious for diabetic mastopathy. Incisional biopsy of the right breast lump was performed. On histopathological examination, the lesion showed fibrosis with dense lymphocytic infiltration around the lobules. Diabetic fibrous mastopathy was diagnosed. Physicians should be aware of the association of long-standing diabetes mellitus with the development of fibrous mastopathy. CT is considered a useful tool to differentiate diabetic mastopathy from breast cancer.

Two special types of breast cancer presenting as progressive disease after neoadjuvant chemotherapy with docetaxel plus doxorubicin.

Seventy-eight patients with primary breast cancer over 3 cm in diameter in stages II A, II B, III A and III B according to the UICC classification received neoadjuvant chemotherapy from August 1, 1998 to June 30, 2000 at the Breast Division of the National Cancer Center Hospital. Neoadjuvant chemotherapy consisted of doxorubicin (Adriamycin: ADM) 50 mg/m(2) and docetaxel (Taxotere: DOC) 60 mg/m(2) every three weeks. The overall clinical response to this regimen was 88% (69/78). Although neoadjuvant chemotherapy with this regimen achieved good responses in patients with breast cancer, 2 patients presented with progressive disease (PD) after treatment. One patient had inflammatory breast cancer (IBC) and the other had primary squamous cell carcinoma (SCC) of the breast. There were 4 cases of IBC and one case of SCC of the breast who received neoadjuvant chemotherapy in this series. Our observations suggest that this regimen might not be effective for these types of breast cancer.

A new prognosis factor analysis based on nonhomogeneous Markov description.

To evaluate prognosis factors, Cox's proportional hazard model has been used. But it was found that the analytical ability was not sufficient. So we propose a new evaluation method combining Markov chain model and multiple logistic regression analysis to estimate the prognosis factors. Stage II breast cancer was chosen as the subject. The data was retrospective data gathered in National Cancer Center Central Hospital. As first step, a simple Markov chain model was constructed to describe the state transition of a breast cancer. Then the multiple property of each state transition was investigated in detail. And the patients who had gotten a recurrence for the first two and a half years were discriminated as the poor prognosis group by a nonparametric test (p < 0.05). And the result proved to corresponding with the clinical experience. As second step, three factors (n classification of pathological diagnosis, ductal spread, and estrogen receptor) were selected as the prognosis factors for the early death in Stage II breast cancer by a multiple logistic regression analysis. This new prognosis factor analysis could find out some scientific evidences. Especially, it was found to be remarkable efficient in proving clinically experienced observation.

Validation and problems of St-Gallen recommendations of adjuvant therapy for node-negative invasive breast cancer in Japanese patients.

BACKGROUND: The objectives of this study were to confirm the favorable outcome of invasive breast cancer in Japanese patients without lymph node metastasis who did not receive adjuvant therapies and to validate the St-Gallen recommendations in this population. METHODS: The subjects were a consecutive series of 920 node-negative invasive breast cancer patients who underwent surgery between 1987 and 1994 at our hospital. These patients did not receive adjuvant chemotherapy. Ten-year disease-free (DFS) and overall survival (OS) rates were analyzed by the St-Gallen risk categories (Minimal/Low, Intermediate, High). RESULTS: The median age of the patients at surgery was 52 years and the median follow-up period of patients was 10.2 years. At 10 years, the respective DFS and OS rates of all patients were 84.6 and 86.7%. The DFS and OS of patients in the Minimal/Low risk category (25 patients) both showed 100%. The DFS and OS of patients in the Intermediate risk category (356 patients) showed 92.0 and 93.1%, respectively. The DFS and OS of patients in the High risk category (539 patients) showed 79.4 and 82.2%, respectively, indicating a significant difference between those in the Minimal/Intermediate risk category (381 patients) (p < 0.001, p < 0.001, respectively). The DFS and OS of patients who had one pathological lymph node metastasis (775 patients) showed 72.7 and 75.2%, respectively, which indicated a non-significant difference between those in the High risk category (381 patients) (p = 0.10). These data support the validation of adjuvant therapy for high-risk node-negative breast cancers in Japanese patients. However, quality control is needed to define the histological grade included in the risk categories. CONCLUSION: Japanese patients with invasive breast cancer without lymph node metastasis showed a survival advantage compared with their Caucasian counterparts. However, patients in the High risk group as defined by St-Gallen recommendations should be indicated for adjuvant therapy.

Primary hepatic carcinoid tumor: case report and review of 53 cases.

BACKGROUND: Primary hepatic carcinoid tumor (PHCT) is a extremely rare. The authors describe a patient with PHCT and review previously published cases of the disease. CASE REPORT: A 75-year-old man, presenting with weight loss and pain in the right upper abdomen, had multiple masses in both lobes of the liver. He was diagnosed as PHCT by radiological examination, laboratory findings with high levels of 5-hydroxyindoleacetic acid (5-HIAA) in the serum and urine, and histological findings including positive staining of tumor cells for Grimelius and chromogranin A. The patient received totally transcatheter arterial chemoembolization (TACE) five times over 27 months; this treatment provided excellent palliation and caused a decrease in urinary 5-HIAA levels. Fifty-three cases of PHCT have been reported in the English-language literature. RESULTS: Analysis of these published cases revealed that PHCT occurs in the middle age (mean age = 48.2 years) and is more frequent in females (males/females = 20/33 cases). Of the symptomatic patients, the major findings is abdominal pain, fullness, and/or a palpable mass (56% of symptomatic patients). In contrast, only 2 cases out of 53 presented with symptoms of typical carcinoid syndrome. In most cases, PHCT was detected as a hypervascular lesion by radiological examination. By histological analysis, 80% and 84% of the cases were positive for Grimelius silver stain and immunohistochemically positive for chromogranin A, respectively. Surgical resection is the treatment primarily recommended with an 18% of recurrence rate and a 74% of a survival rate after 5 years. For unresectable and recurrent cases, TACE may be recommended.

Differences in estrogen receptor status, HER2, and p53 comparing metachronous bilateral breast carcinoma.

BACKGROUND AND OBJECTIVES: We analyzed the clinicopathologic characteristics and tumor biology of metachronous bilateral breast carcinoma with regard to p53, HER2 and hormone receptor status. METHODS: A consecutive series of 54 female metachronous bilateral breast carcinoma patients treated at the National Cancer Center Hospital between 1980 and 1997 were the primary source of these retrospective data. Clinicopathologic background factors were analyzed, and immunohistochemical staining for p53, HER2, and hormone receptor status was carried out on paraffin-embedded specimens. RESULTS: There were no significant differences in clinical stage, p53 and HER2 expression levels between the first and second primary tumors. The positive rates for ER and PR were 48% (25 of 52) and 46% (25 of 54) for the first tumors, but only 19% (10 of 52) and 32% (17 of 54) for the second tumors (P = 0.004 for ER, P = 0.16 for PR), showing a significant loss of ER. CONCLUSIONS: Our findings indicate that p53 and HER2 expression levels in the second tumors might be the same as those of the first tumors in metachronous bilateral breast carcinoma; however, loss of ER was more frequently observed in the second primary tumors than in the first tumors.

Pattern of chromosome 16q loss differs between an atypical proliferative lesion and an intraductal or invasive ductal carcinoma occurring subsequently in the same area of the breast.

Atypical proliferative lesions of the breast, such as atypical ductal hyperplasia and atypical papilloma, are considered to be precursors of breast carcinomas and have frequently been shown to have loss of heterozygosity (LOH) on chromosome 16q at the DNA level. We evaluated whether an atypical proliferative lesion and a carcinoma that subsequently occurred in the same area of the ipsilateral breast were of identical clonal origin in seven patients. Using DNA isolated from microdissected archival tissue of epithelial components of both the biopsy specimen of the atypical proliferative lesion and the mastectomy specimen of the carcinoma, the pattern of LOH on 16q was compared between these two lesions using polymerase chain reaction -microsatellite LOH analysis. As a control, LOH on 16q was examined in 13 cases of usual ductal hyperplasia, 10 usual papillomas, and 6 atypical ductal hyperplasias. In the seven cases, LOH on 16q was detected in three of the six atypical proliferative lesions and in five of the seven carcinomas, but the allele with LOH or a deleted region always differed between the two. LOH was detected in both atypical proliferative lesions and carcinomas in one case, only in the atypical proliferative lesion in two cases, and only in carcinomas in three cases. In the controls, LOH on 16q was absent in usual ductal hyperplasias or usual papillomas but was detected in two of six atypical ductal hyperplasias. Although atypical proliferative lesions were frequently confirmed to be of clonal nature with LOH on 16q, these lesions and carcinomas were considered to be clones, probably originated from a field with these clones.

Correlation of genetic etiology with response to beta-adrenergic blockade among symptomatic patients with familial long-QT syndrome.

Mutations in any of the five genes KCNQ1, KCNH2, KCNE1, KCNE2, and SCN5A can be responsible for familial long QT syndrome (LQTS), an arrhythmogenic disorder that entails a high risk of sudden death. beta-Adrenergic blocking agents are the first therapeutic choice, and 80% of patients treated with these agents show symptomatic relief; however the remaining 20% do not respond well. We previously performed a nationwide analysis of familial long QT syndrome (LQTS) in Japan and identified 32 mutations in the KCNQ1 and KCNH2 genes. In the present retrospective study, we found that patients carrying mutations in the KCNQ1 gene responded better to beta-adrenergic blocking agents than those with KCNH2 mutations (12 of 13 vs 1 of 5; P = 0.0077, Fisher's exact test). This is a good example of the power of genetic diagnosis to direct the selection of appropriate therapy for patients with diseases of heterogeneous genetic etiology.

Effect of probucol in lecithin-cholesterol acyltransferase-deficient mice: inhibition of 2 independent cellular cholesterol-releasing pathways in vivo.

Cellular cholesterol release takes place by at least 2 distinct mechanisms: the lecithin-cholesterol acyltransferase (LCAT)-driven net efflux by cholesterol diffusion and the generation of high density lipoprotein (HDL) with cellular cholesterol and phospholipid on the cell-apolipoprotein interaction. Therefore, LCAT deficiency impairs the former pathway, and the latter can be inhibited by probucol, which interferes with the apolipoprotein-cell interaction. Hence, probucol was given to the LCAT-deficient mice in the attempt to suppress both of these pathways. The mice were fed low (0.2%) and high (1.2%) cholesterol diets containing 0.5% probucol for 2 weeks. LCAT deficiency and probucol markedly decreased plasma HDL, and the effects were synergistic. Tissue cholesterol content was lower in the adrenal glands and ovaries in the LCAT-deficient mice and in the probucol-treated mice, suggesting that HDL is a main cholesterol provider for these organs. It was also moderately decreased in the spleen of the low cholesterol-fed female mice and in the thyroid gland of the low cholesterol-fed male mice. On the other hand, the esterified cholesterol content in the liver was substantially increased by the probucol treatment with a high cholesterol diet in the LCAT-deficient mice but not in the wild-type mice. Among the groups, there was no significant difference in the tissue cholesterol levels in other organs, such as the liver, spleen, thymus, brain, erythrocytes, thyroid gland, testis, and aorta, resulting from either LCAT deficiency or probucol. Thus, the apolipoprotein-mediated mechanism plays a significant role in the export of cellular cholesterol in the liver, indicating that the liver is a major site of the HDL assembly. Otherwise, tissue cholesterol homeostasis can largely be maintained in mice even when the assembly of new HDL is inhibited by probucol in the absence of LCAT. Nonspecific diffusion of cholesterol perhaps adequately maintains the homeostasis in the experimental condition.