Quantitative analysis of surface P-wave morphology in isthmus ablation for type 1 atrial flutter: differentiation between complete isthmus block and slow isthmus conduction

Changes in P-wave morphology in inferior leads during atrial pacing at the margins of the carvo-tricuspid isthmus have been reported to be useful for predicting the creation of isthmus block in radiofrequency (RF) ablation of type I atrial flutter (AFL). However, it is not known whether these changes in P-wave morphology allow the clinician to differentiate between complete isthmus block and slow isthmus conduction. P-wave morphology during low lateral right atrial (LLRA) pacing, as well as during coronary sinus ostium (PCS) pacing, was evaluated prior to ablation, during slow isthmus conduction, and after complete isthmus block in 30 patients with AFL. Changes in P-wave morphology during LLRA pacing were not sufficient to differentiate between complete isthmus block and slow isthmus conduction. While changes in P-wave morphology in lead II from inverted to biphasic during PCS pacing were observed in both slow isthmus conduction and complete isthmus block, the ratio of the positive component to the total P-wave amplitude (P-wave ratio) was significantly different between slow isthmus conduction (20+/-17%) and complete isthmus block (40+/-11%) (P<0.0001). When the P-wave ratio in lead II during PCS pacing was more than 75% of the F-wave ratio in lead II during AFL, bilateral complete isthmus block was predicted with a sensitivity of 88%, a specificity of 71%, a positive predictive value of 75%, and a negative predictive value of 85%. These results indicate that a P-wave ratio greater than 20% or a P-wave ratio during PCS pacing greater than 75% of the F-wave ratio during AFL may predict a bidirectional complete isthmus block.

Isolation of a human rotavirus strain with a super-short RNA pattern and a new P2 subtype

Super-short rotavirus strains that have a rearranged gene segment 11 are rarely found in humans, and only five isolates, all from Southeast Asia, have been described in the literature. We report the first isolation in Japan from an infant with severe diarrhea of a rotavirus possessing a super-short RNA pattern. This strain, designated AU19, had a G1 VP7 and is also the first isolate in Japan that possesses a P2[6] VP4. Furthermore, the P2[6] VP4 carried by AU19 was divergent in the hypervariable region of the amino acid sequence from the P2A[6] VP4s carried by asymptomatic neonatal strains or from the P2B[6] VP4 carried by porcine rotavirus strain Gottfried. Thus, AU19 is likely to represent a new VP4 subtype, which we propose to call P2C. Given the recent emergence of the P2[6] VP4s in India, Brazil, and the United States and the role of VP4 in protective immunity, further scrutiny is justified to see whether the emergence of the previously underrepresented P2[6] VP4 serotype is related to this new P2 subtype.

Genomic structure of the canalicular multispecific organic anion-transporter gene (MRP2/cMOAT) and mutations in the ATP-binding-cassette region in Dubin-Johnson syndrome

Dubin-Johnson syndrome (DJS) is an autosomal recessive disease characterized by conjugated hyperbilirubinemia. Previous studies of the defects in the human canalicular multispecific organic anion transporter gene (MRP2/cMOAT) in patients with DJS have suggested that the gene defects are responsible for DJS. In this study, we determined the exon/intron structure of the human MRP2/cMOAT gene and further characterized mutations in patients with DJS. The human MRP2/cMOAT gene contains 32 exons, and it has a structure that is highly conserved with that of another ATP-binding-cassette gene, that for a multidrug resistance-associated protein. We then identified three mutations, including two novel ones. All mutations identified to date are in the cytoplasmic domain, which includes the two ATP-binding cassettes and the linker region, or adjacent putative transmembrane domain. Our results confirm that MRP2/cMOAT is the gene responsible for DJS. The finding that mutations are concentrated in the first ATP-binding-cassette domain strongly suggests that a disruption of this region is a critical route to loss of function.

Pseudovascular squamous cell carcinoma of the uterine cervix: a lesion that may simulate an angiosarcoma

A case of pseudovascular squamous cell carcinoma in the uterine cervix of a 64-year-old woman was examined. Histologically, the lesion consisted of atypical, large, non-keratinizing squamous cells that exhibited not only acantholytic changes but also pseudovascular changes. Immunohistochemically, these tumor cells were positive for cytokeratin, epithelial membrane antigen and carcinoembryonic antigen, but none of them were positive for Factor VIII-related antigen or CD34. To our knowledge, pseudovascular carcinoma of the uterine cervix has not been described in the literature. Pathologists should be aware of this unusual form of cervical squamous cell carcinoma, particularly in the differential diagnosis of angiosarcoma.

Anti-inflammatory drugs and endothelial cell adhesion molecule expression in murine vascular beds

BACKGROUND

Inflammatory bowel diseases (IBD) are characterised by an intense infiltration of leucocytes that is mediated by adhesion molecules expressed on the surface of activated endothelial cells.

AIMS

To determine whether drugs used in the treatment of IBD, specifically dexamethasone (DEX), 5-aminosalicylic acid (5-ASA), methotrexate (MTX), and 6-mercaptopurine (6-MP), alter the expression of endothelial cell adhesion molecules (ECAMs).

METHODS

The expression of P-selectin, E-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular CAM 1 (VCAM-1) in different vascular beds of C57Bl/6J mice was measured using the dual radiolabelled monoclonal antibody technique.

RESULTS

Lipopolysaccharide (LPS) elicited a profound increase in the expression of all ECAMs in the mesentery, small intestine, caecum, and distal colon. The LPS induced increase in CAM expression was not significantly affected by prior treatment with either MTX or 6-MP. However, pretreatment with either DEX or 5-ASA significantly attenuated LPS induced increases in expression of P- and E-selectin, and VCAM-1 in the majority of tissues evaluated. DEX also blunted the LPS induced increase in ICAM-1 expression in the caecum and distal colon. DEX, but not 5-ASA, largely abolished the rise in plasma tumour necrosis factor alpha elicited by LPS.

CONCLUSIONS

These findings suggest that DEX and 5-ASA may exert their beneficial therapeutic action in IBD, at least in part, by inhibiting the expression of ECAMs which mediate leucocyte adhesion and transmigration in the microvasculature.

Simple electrocardiographic criteria for identifying the site of origin of focal right atrial tachycardia

To construct an algorithm for identifying the precise site of origin of focal right atrial tachycardia (RAT), we analyzed the P wave configuration in 32 patients with RAT who underwent successful radiofrequency catheter ablation. The RA was divided into three areas in the left anterior oblique view: superolateral, inferolateral, and inferomedial. There were 17 RATs arising from the crista terminalis (CT-AT), 12 from the tricuspid annulus (TA-AT), and 3 from the septum away from the TA (Sep-AT). A negative P wave in lead aVR identified CT-AT with a sensitivity (sens) of 100% and a specificity (spec) of 93%. In CT-ATs, positive P waves in the inferior leads differentiated superolateral AT from inferolateral AT with a sens of 86% and a spec of 100%. In any type of AT with inferomedial or inferolateral foci, the P wave deflections in at least one of the inferior leads was negative, and negative P waves in leads V5 and V6 identified inferomedial AT with a sens of 92% and a spec of 100%. In ATs near the apex of Koch's triangle, the P wave duration in the inferior leads was shorter than during sinus rhythm.

CONCLUSIONS

(1) the P wave configuration in lead aVR can easily differentiate CT-AT from TA-AT and Sep-AT; (2) the P wave configuration in the inferior leads helps to determine a superior versus inferior origin in any type of AT; (3) in inferior AT, the P wave polarity in leads V5 and V6 is useful in determining a lateral versus medial origin; (4) this algorithm can predict accurately the origin of AT.

Transgenic mice with increased copper/zinc-superoxide dismutase activity are resistant to hepatic leukostasis and capillary no-reflow after gut ischemia/reperfusion

The objectives of this study were to (1) determine whether transgenic (Tg) mice overexpressing copper/zinc-superoxide dismutase (CuZn-SOD) are protected from the deleterious effects of gut ischemia/reperfusion (I/R) and (2) compare the effectiveness of Tg SOD overexpression in attenuating I/R injury to intravascularly administered CuZn-SOD or manganese (Mn)-SOD. The accumulation of fluorescently labeled leukocytes and number of nonperfused sinusoids were monitored by intravital microscopy in livers of wild-type mice (C57BL/6), CuZn-SOD Tg mice, and wild-type mice receiving either CuZn-SOD or Mn-SOD. All parameters were measured for 1 hour after release of the occluded (for 15 minutes) superior mesenteric artery. Gut I/R in wild-type mice led to an increased number of stationary leukocytes, while reducing the number of perfused sinusoids (capillary no-reflow). All of these responses were significantly blunted in CuZn-SOD Tg mice, with a corresponding attenuation of liver enzyme release into plasma. Exogenously administered SOD had little or no effect on gut I/R-induced leukostasis or capillary no-reflow in the liver. These observations suggest a role for superoxide in gut I/R-induced leukostasis and hypoxic stress in the liver. Furthermore, the findings suggest that cellular localization of SOD activity is an important determinant of the protective actions of this enzyme in experimental models of I/R injury.

Refractory ascites due to portal vein thrombosis in liver cirrhosis--report of two cases

Portal vein thrombosis as a complication of liver cirrhosis has been reported to be extremely rare in Japan, as compared with European countries. There are few reports discussing the correlation of portal vein thrombosis with refractory ascites. Between January 1994 and December 1995, 20 cases (91%) of 22 patients with liver cirrhosis with ascites admitted to our hospital responded well within 2 months to a combination therapy of diuretics and albumin infusion, and the other two cases (9%) with refractory ascites were associated with portal vein thrombosis. The ascites in the first patient continued for 1 year, despite diuretics and albumin infusion therapy, and portal vein thrombosis was confirmed by autopsy. The ascites in the other patient continued for more than 4 months, and portal vein thrombosis was detected by ultrasound. Portal vein thrombosis was not found in the other 20 cirrhotic patients with ascites. These two cases suggest that portal vein thrombosis may be a contributing factor to refractory ascites in patients with decompensated liver cirrhosis.

Nitric oxide modulates gut ischemia-reperfusion-induced P-selectin expression in murine liver

Reperfusion of ischemic intestine is associated with P-selectin-dependent adhesion of leukocytes in the liver microcirculation. The objective of this study was to define the contribution of nitric oxide (NO) to the enhanced P-selectin expression and increased leukocyte rolling elicited by gut ischemia-reperfusion (I/R). Leukocyte rolling (monitored by intravital microscopy) in the terminal hepatic venules (THV) and P-selectin expression (measured using the dual-radiolabeled monoclonal antibody technique) were determined in mice after 15 min of superior mesenteric artery occlusion and 30 min of reperfusion. After 30 min of reperfusion, P-selectin expression was significantly increased in the liver, intestine, and lung, with a corresponding increase in the number of rolling leukocytes (in THV). The NO synthase inhibitor NG-monomethyl-L-arginine exaggerated the gut I/R-induced increases in both rolling leukocytes and P-selectin expression (in liver and intestine), responses that were not detected with coadministration of L-arginine or in P-selectin-deficient mice. The NO donor diethylenetriamine/NO and L-arginine were both effective in attenuating the gut I/R-induced increases in rolling leukocytes (in THV) and P-selectin expression (in liver, intestine, and lung). These findings indicate that NO modulates gut I/R-induced recruitment of rolling leukocytes in THV via an action on P-selectin expression.

No Mycobacterium paratuberculosis detected in intestinal tissue, including Peyer's patches and lymph follicles, of Crohn's disease

To clarify the etiologic significance of Mycobacterium paratuberculosis in Crohn's disease, we investigated whether M. paratuberculosis was detected in intestinal tissues, including Peyer's patches, where M. paratuberculosis invades, and colonic lymph follicles, where early lesions appear. Fifty-one samples of intestinal tissues, either therapeutically resected or biopsied, including 34 specimens from 30 patients with Crohn's disease, were studied. Four Peyer's patches and eight lymph follicles were included in the intestinal tissue samples of Crohn's disease. They were visualized by acetic acid fixation. DNA extracted from intestinal tissues by proteinase K treatment was used for nested polymerase chain reaction (PCR) for detection of IS900, which is specific for M. paratuberculosis. PCR products were analyzed by agarose gel electrophoresis and subsequent Southern blot analysis. Our amplification system could detect 7.5 fg of M. paratuberculosis DNA. None of the tissue samples showed positive IS900 amplification, whereas they all showed amplification of the positive control human leukocyte antigen (HLA)-DQA DNA. Spiked experiments of tissue samples with M. paratuberculosis demonstrated that inhibitors of IS900 amplification were not present in the samples. Our study does not support the etiologic significance of M. paratuberculosis in Crohn's disease.

Conserved structural features of nonstructural glycoprotein NSP4 between group A and group C rotaviruses

The nonstructural glycoprotein NSP4 of group C human rotavirus strain Ehime 9301 was determined to be 150 amino acids in length and 96% identical with the NSP4 of another group C human rotavirus strain Bristol. Both NSP4 sequences were virtually unrelated to group A rotavirus NSP4s. However, the structural features of group A and group C rotavirus NSP4s were similar with hydrophobic domains being in the amino terminus and a coiled coil domain after the membrane-spanning domain, although group C rotavirus NSP4 lacked one amino-terminal hydrophobic domain.

Hypoplasia of the left hepatic lobe associated with floating gallbladder: a case report

Agenesis or hypoplasia of the hepatic lobe and floating gallbladder are both rare. We report an extremely rare case of hypoplasia of the left hepatic lobe accompanied by floating gallbladder. The patient was a 71-year-old woman, with no past history of related symptoms, who was admitted for further evaluation of postprandial epigastralgia, nausea, and diarrhea. Laboratory data on admission showed chronic liver disease with positive anti-hepatitis C virus antibody. Abdominal ultrasonography and computed tomography revealed the absence of the left hepatic lobe and displacement of the gallbladder to the left. On endoscopic retrograde cholangiography, the cystic duct originated from the right side of the bile duct, but the gallbladder was displaced to the left. Poor yolk-induced gallbladder contraction suggested the existence of hypotonic biliary dyskinesia. Angiography demonstrated no middle or left hepatic arteries, indicating congenital hypoplasia of the left hepatic lobe. Open cholecystectomy was carried out, and a diagnosis of hypoplasia of the left hepatic lobe accompanied by floating gallbladder and chronic hepatitis was confirmed. We believe that this is the first reported case of a hypoplasia of the left hepatic lobe coexisting with floating gallbladder.

Listeria monocytogenes in Crohn's disease

BACKGROUND

In an immunohistochemical study a higher rate of reactivity of intestinal tissues to the antibody against Listeria monocytogenes was reported in Crohn's disease as compared with controls.

METHODS

Seventy-six intestinal tissues, either therapeutically resected or biopsied, from 31 patients with Crohn's disease, 20 with ulcerative colitis, and 21 with non-inflammatory bowel disease were studied. DNA extracted from intestinal tissues by proteinase K treatment was used for nested polymerase chain reaction (PCR), using two sets of primers. PCR products were analyzed with agarose gel electrophoresis and subsequent Southern blot analysis.

RESULTS

Our amplification system could detect 9 pg of L. monocytogenes DNA. L. monocytogenes was detected in only one sample, that from a patient with ulcerative colitis.

CONCLUSIONS

Our study does not support the etiologic significance of L. monocytogenes in Crohn's disease.

Induction of major histocompatibility complex class II antigens on human colonic epithelium by interferon-gamma, tumor necrosis factor-alpha, and interleukin-2

Class II antigens are strongly expressed on the inflamed colonic epithelium in inflammatory bowel disease. However, the mechanism of this epithelial class II antigen induction is not fully understood. Increased activities of interferon (IFN)gamma, tumor necrosis factor (TNF)alpha, and interleukin (IL)2 have been shown in the inflamed mucosa of inflammatory bowel disease. Therefore, we studied whether these cytokines could induce class II antigens on the human colonic epithelium. By an organ culture technique, 284 normal colonic biopsy specimens obtained from 49 individuals were cultured in media containing different concentrations of cytokines with/without anti-IFNgamma R antibody. Colonic epithelial class II antigens were identified by the indirect immunoperoxidase staining method with anti-human leukocyte antigen (HLA)-DR, DP, and DQ monoclonal antibodies. IFNgamma, TNFalpha, and IL2 induced epithelial class II antigens in 16 of 16 cases (100%), 2 of 16 cases (12.5%), and 6 of 17 cases (35%), respectively. Epithelial class II antigen expression in response to TNFalpha was induced via IFNgamma but not via IL2. This is the first demonstration that: (i) the induction of class II antigens on the colonic epithelium in response to TNFalpha is mediated via IFNgamma, and (ii) that IL2 induces class II antigens.

Superior sagittal sinus thrombosis associated with primary antiphospholipid syndrome--case report

A 36-year-old female with a history of recurrent pregnancy loss experienced sudden onset of disturbance in consciousness, with right hemiparesis and total aphasia. Computed tomography revealed a massive hemorrhage in the left frontal lobe, and angiography showed occlusion of the anterior two-thirds of the superior sagittal sinus. Laboratory investigations detected the presence of lupus anticoagulant, elevation of the anticardiolipin beta 2-glycoprotein I complex antibody level, and a decreased protein S activity level. There were no underlying conditions, such as connective tissue disorders, malignancies, infectious diseases, and drug-induced disorders, so the diagnosis was primary antiphospholipid syndrome. Primary antiphospholipid syndrome should be considered in the evaluation of patients with "idiopathic" or "primary" sinus and cerebral venous thrombosis.

Mutation in the exon 10 (R173W) of the hydroxymethylbilane synthase gene in two unrelated Japanese families with acute intermittent porphyria

Acute intermittent porphyria (AIP) is an inherited disorder characterized by a deficiency of hydroxymethylbilane synthase (EC 4.3.1.8.; HMBS), the third enzyme in the heme biosynthetic pathway. To date, 113 different HMBS gene mutations have been reported in the world. However, there were a few reports of the gene mutations in the Japanese AIP patients. We studied the gene mutation in two unrelated AIP families in the San-in district, a local area of Western Japan. The overlapping 6 fragments of the HMBS gene, amplified by the reverse transcript-polymerase chain reaction, were analyzed by the single-strand conformation polymorphism with silver staining technique. The abnormal fragment from a member of one family was sequenced to detect the C to T substitution at 517 nucleic acid position of cDNA, which led to a missense mutation of arginine to tryptophan exchange at an amino acid level (R173W). This mutation located in exon 10 created a new site of the MSP 1 restriction endonuclease and was screened by the amplified fragment of exon 10 from genomic DNA with the MSP 1 digestion. The mutation was detected totally in three members of the family and interestingly also in two patients of an unrelated family. This mutation has been reported widely in the world independently, such as in a Swedish, a Canadian, a Finnish, and a French family, but is the first in Japanese patients. The screening method for this mutation is useful for diagnosis in Japanese AIP patients.

Antigenic similarities to Paracoccidioides brasiliensis in thermo-dependent dimorphic fungi isolated from soil in Botucatu, SP, Brazil

We compared the antigenic characteristics of two thermo-dependent dimorphic fungi isolated from soil in Botucatu, an endemic area of paracoccidioidomycosis (PCM) and Paracoccidioides brasiliensis. The soil isolates grew as cerebriform colonies at 37 degrees C (yeast form) and as cottonous colonies at 25 degrees C (mycelial form). No pathogenicity for ddY mice or hamsters were observed. In immunodiffusion test, there were precipitation bands between the 2 soil isolates and pooled PCM patient sera. There were also common precipitation bands at 21, 50 and 58 kDa between the soil isolates antigens and PCM patient sera by Western-blotting, but no gp43 kDa band. No gene for gp 43 kDa protein was detected in the soil isolates by PCR. The fact that these isolates were obtained from an endemic area of PCM and there were some antigenic similarities between the soil isolates and P. brasiliensis in immunodiffusion test and Western-blotting may have some importance in epidemiological surveys done with paracoccidioidin as well interfering with the immune response of the exposed population.

Role of Kupffer cells in gut ischemia/reperfusion-induced hepatic microvascular dysfunction in mice

Kupffer cells (KCs) have been implicated in the leukocyte recruitment and microvascular dysfunction associated with liver inflammation. The overall objective of this study was to assess the role of KCs in the leukocyte adhesion and oxidative stress elicited in the liver by gut ischemia/reperfusion (I/R). The accumulation of rhodamine-6G-labeled leukocytes and the number of nonperfused sinusoids (NPS) were monitored (by intravital microscopy) in mouse liver for 1 hour after a 15-minute period of normothermic intestinal ischemia. Autofluorescence of pyridine nucleotide [NAD(P)H] was measured as an index of mitochondrial O2 consumption and redox status. Leukostasis, as well as increases in NPS and NAD(P)H autofluorescence (indicating hypoxia), were observed in the liver at 60 minutes after gut I/R. Pretreatment with gadolinium chloride (GdCl3), which reduces KC function, attenuated the liver leukostasis and NPS elicited by gut I/R. The platelet activating factor (PAF) antagonist, WEB2086, and a tumor necrosis factor (TNF)-alpha-specific antibody were also effective in attenuating the gut I/R-induced leukostasis and NAD(P)H autofluorescence. The findings of this study suggest that KCs play an important role in mediating the leukocyte recruitment, impaired sinusoidal perfusion, and tissue hypoxia elicited in the liver after gut I/R. These KC-mediated responses appear to involve the participation of both PAF and TNF-alpha.

MRI appearances of fascioliasis complicating liver iron overload

A case of hepatic fascioliasis with an unusual appearance on MRI due to liver iron overload is presented. The diagnosis of fascioliasis was based on positive serological tests and the presence of eggs in the bile. Hepatic lesions of fascioliasis exhibited hyperintense signals on T1 weighted images as well as proton density and T2 weighted images. Histological study of biopsy specimens from the lesions showed central necrosis and peripheral fibrosis with inflammatory cells including eosinophils. Abundant iron deposition in hepatocytes and Kupffer cells was found in specimens from the surrounding liver. These findings suggested that this appearance on MR images was probably due to a decrease in signal intensity in surrounding liver.

Effect of lipopolysaccharides on erythrocyte flow velocity in rat liver

Although endotoxin exacerbates hepatic microcirculatory disturbance, little is known of the way in which it acts on the hepatic microcirculation. We measured endotoxin-induced changes in hepatic microcirculation and investigated the effect of endotoxin on hepatic microcirculation in rats. After male Wistar rats were anesthetized, a lobe of the liver was observed with an inverted intravital microscope. Erythrocytes (RBC) were labeled with fluorescein isothiocyanate (FITC) and injected. The flow velocity (FV) of FITC-RBC in sinusoids was measured with an off-line velocimeter. Portal pressure (PP) and mean arterial pressure (MAP) were measured with a catheter cannulated in the portal vein and the left carotid artery, respectively. After a small dose (1 mg/kg) of endotoxin had been administered intravenously, FV decreased and PP increased gradually after 30 min. MAP showed no significant change, except for an initial decrease. However, when 5 mg/kg of endotoxin was administered, FV and PP increased, with a peak at 10 min, which was not observed with the small dose. In the late phase, FV decreased and PP increased, as was seen with the small dose. Endotoxin increased serum aspartate aminotransferase and lactate dehydrogenase activities. These results suggest that endotoxin induces hepatic microcirculatory disturbance, which may cause liver injury.

Metastatic Crohn's disease involving the penis

Metastatic Crohn's disease is a rare complication in Crohn's disease and there have been only several cases of metastatic Crohn's disease involving the penis. We report one such case. A 22-year-old male student developed anal pain and alternative constipation and diarrhea in December, 1985, followed by diarrhea and lower abdominal pain in January, 1986. He was diagnosed as having Crohn's disease of ileocolitis type. He was admitted to our hospital in July, 1987 because of exacerbation of Crohn's disease. He had anal tags. Soon after admission, two red swollen lesions with central ulcer and erosions were demonstrated at the eversion of the foreskin adjacent to coronal sulcus. Histology of the lesions revealed granulomas with epithelioid cells and giant cells. The lesion responded to a topical steroid. Eight cases of metastatic Crohn's disease involving the penis are briefly reviewed.

Induction of megamitochondria by some chemicals inducing oxidative stress in primary cultured rat hepatocytes

Effects of hydrazine, hydrogen peroxide and bromobenzene, inducers of free radicals, and those of erythromycin and cycloheximide, inhibitors of protein synthesis on structural changes of mitochondria in primary monolayer culture of rat hepatocytes were examined using laser confocal microscope and electron microscope. After 22 h of incubation of hepatocytes with 0.2 mM hydrogen peroxide or 10 microg ml-1 of erythromycin, mitochondria became extremely enlarged. Mitochondria of hepatocytes isolated from control rats became slightly to moderately enlarged in the presence of 2 mM hydrazine, while those of hepatocytes isolated from phenobarbital-pretreated animals became extremely enlarged in the presence of 2 mM hydrazine. Cycloheximide (0.5-10.0 microg ml-1) and bromobenzene (0.1-1.0 mM) failed to induce structural changes of mitochondria. The level of cytochrome P-450 in freshly prepared hepatocytes from phenobarbital-treated rats was 2.5 times higher than that from the control rats, and remained about three times higher than the latter after 22 h of incubation with 2 mM hydrazine. The level of malondialdehyde was invariably elevated when megamitochondria were induced. These results may suggest that oxidative stress is intimately related to the mechanism of the formation of megamitochondria and that the inhibition of cytoplasmic protein synthesis seems not to contribute the phenomenon. However, the detailed mechanism by which free radicals may induce megamitochondria remains to be elucidated.

Thrombophlebitis of the inferior vena cava involving the retroperitoneum with Crohn's disease: MR demonstration

We present a case of thrombophlebitis of the inferior vena cava (IVC) with Crohn's disease after intestinal perforation and prolonged indwelling of a catheter in the IVC. Magnetic resonance imaging demonstrated abnormal thickening and enhancement of the IVC wall. In addition, IVC thrombus formation was shown. The abnormal enhancement extended from the wall in the pericaval tissue and into the retroperitoneum, and regressed as the Crohn's disease subsided.