[A case of pulmonary arteriovenous fistula presenting as multiple brain abscesses after a sustained period without treatment]

A 64-year-old man was admitted to our hospital with multiple brain abscesses accompanied by pulmonary arteriovenous fistula (PAVF). He had been diagnosed with PAVF eight years previously, but had refused any treatment despite a developing exertional dyspnea. Rendu-Osler-Weber disease was diagnosed as well because the patient exhibited teleangiectasis of the nasopharyngeal mucosa and persistent gastro-intestinal bleeding. Despite administration of antibiotics and corticosteroids the abscesses perforated into the lateral ventricle. The natural history of this rare disease is still incompletely understood. Thus, the time at which treatment should be commenced remains unclear. However the natural course of PAVF is unsatisfactory, and it appears that treatment by surgery and/or embolization should be considered in all cases.

Modulation of cytokine production and protection against lethal endotoxemia by the cardiac glycoside ouabain

BACKGROUND

Recent studies have shown that cytokines are capable of modulating cardiovascular function and that some drugs used in the treatment of heart failure variably modulate the production of cytokines. To examine whether cardiac glycosides also modulate cytokine production, we evaluated the effects of ouabain on the production of cytokines in vitro and in vivo.

METHODS AND RESULTS

Human peripheral blood mononuclear cells (PBMC) were obtained from healthy volunteers. PBMC were cultured with or without ouabain in the presence or absence of lipopolysaccharide (LPS). Ouabain induced the production of interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha in PBMC and induced mRNA of these cytokines, an induction apparently at the transcriptional level. Amiloride, staurosporin, and genistein inhibited cytokine production, and protein kinase C and tyrosine kinase appeared to be involved in the modulation of cytokine production induced by ouabain. However, when PBMC were stimulated with LPS, ouabain suppressed the production of IL-6 and TNF-alpha. To investigate whether ouabain modulates cytokine production in vivo, we evaluated the effects of ouabain in LPS-treated mice. Ouabain was found to protect against LPS-induced lethal toxicity in mice and decreased circulating IL-6 and TNF-alpha levels in vivo.

CONCLUSIONS

These previously unrecognized immunomodulating effects of a cardiac glycoside may explain either the beneficial or the detrimental effects of these drugs in heart failure patients.

A unique response to staphylococcal enterotoxin B by intrahepatic lymphocytes and its relevance to the induction of tolerance in the liver

It has been reported that the intrahepatic lymphocyte (IHL) population is somewhat differently constituted from lymphocytes in other lymphoid tissues. Staphylococcal enterotoxin B (SEB) is a superantigen which can induce T-cell tolerance in mice. The authors investigated the in vitro and in vivo responses of mouse IHL to SEB. An intravenous injection of SEB did not result in the augmentation of the proliferative response of IHL, while mesenteric and splenic lymphocytes (mLNC and SPC, respectively) had augmented responses. Interleukin-2 (IL-2) mRNA was clearly detected in mLNC and SPC by reverse transcriptase-polymerase chain reaction (RT-PCR) shortly after the administration of SEB, but it was scarcely expressed in IHL. The expression of CD25 (IL-2 receptor) was also augmented in mLNC and SPC in the early period, while it was not changed in IHL. These findings suggested that the time required for tolerance induction is different locally and that the loss of augmentation of IL-2 and IL-2 receptor production by IHL may be relevant to the rapid induction of T-cell tolerance in the liver.

Evaluation of prognostic factors following expansive laminoplasty for cervical spinal stenotic myelopathy

BACKGROUND

Expansive laminoplasty of several types has been proposed for patients with cervical multisegmental stenotic myelopathy to reduce postlaminectomy complications. Its effectiveness has not been fully explored by evaluating long-term results and magnetic resonance imaging (MRI) findings before and after surgery.

METHODS

We conducted a 5-year follow-up study of 22 patients with cervical spondylotic myelopathy and/or ossification of the posterior longitudinal ligament surgically treated with expansive laminoplasty. The operative results were examined using the Japanese Orthopedic Association (JOA) disability scale, with reference to the findings of MRI, computed tomography, and radiography.

RESULTS

Postoperative improvement was observed in 18 (81.8%) of the 22 patients. In 11 patients the percentage recovery of the JOA score was higher than 50% (average: 83.1%), while in the remaining 11 patients it was lower than 50% (average: 20.1%). Factors contributing to incomplete recovery appear to be related mainly to cord degeneration with atrophy (depicted as a T2-high intensity area) and to specific factors such as long symptom duration, age higher than 70 years, deterioration due to trauma, severe cord compression, radiculopathy, and kyphotic cervical curvature.

CONCLUSIONS

In cervical myelopathy, patients with multisegmental stenosis, expansive laminoplasty can be expected to provide a favorable outcome by providing sufficient cord decompression and stabilization of the cervical spine, when the stenotic cervical canal is enlarged to the normal range (over 12 mm residual anteroposterior diameter and 200 mm2 residual canal area). The efficacy can be restricted by various factors, especially irreparable cord degeneration.

Augmentation of natural killer cell activity induced by cytomegalovirus infection in mice treated with FK506

Comparable rates of patient and graft survival after FK506 and cyclosporine treatments have been reported in the prevention of liver allograft rejection. On this basis, we examined the effect of FK506 on pathogenesis of cytomegalovirus (CMV) infection in mice. FK506 induced apparent immunosuppression in mice which could be monitored by the level of antibody production. The effective dose of trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH) for 50% reduction in antibody production was 0.9 mg/kg. Even in such an immunosuppressed status at this or higher dose of FK506, CMV infection was relatively alleviated, which was observed by the frequency of virus isolation and the mean virus titer of the lungs of mice treated with 0.1-1 mg/kg FK506 in comparison to untreated mice. The dose of FK506 attaining 50% frequency of lung infection was 1.5 mg/kg. The activity of natural killer (NK) cells was enhanced in infected mice. This enhancement was stronger in infected mice treated with FK506 at 0.32 mg/kg and 10 mg/kg than in untreated infected mice on day 3 post infection (p.i.). Thus, an immunosuppressant FK506 augmented inducible NK cell activity and alleviated MCMV infection even under immunosuppression.

Migration of Gianturco expandable metallic stents in the upper trachea

Endotracheal expandable metallic stents have been shown to be useful in treating malignant tracheobronchial stenosis. We report two cases of early stent migration in the upper trachea after what appeared to be a successful stent placement. We conclude that care should be taken when placing Gianturco stents across short, extrinsic, stenotic lesions with smooth mucosa located in the upper trachea because they have a tendency to migrate.

Effects of extracellular ATP on cytosolic Ca2+ concentration and secretory responses in rat parotid acinar cells

At concentrations >50 microM, extracellular ATP dose-dependently increased cytosolic Ca2+ concentration ([Ca2+]i) via activation of P(2Z) purinoceptors in rat parotid acinar cells. This increase in [Ca2+]i is primarily due to entry of Ca2+ from the extracellular medium. Inositol trisphosphate formation and Ca2+ release from intracellular Ca2+ stores were slightly stimulated by ATP. These responses seem to result from the activation of a P2 purinoceptor subtype different from P(2Z) because the maximum responses were induced by much lower concentrations ( <0.25 mM) of ATP than those (> 1 mM) required to produce the maximum activation of Ca2+ entry. ATP did not stimulate amylase release, supporting the view that an increase in [Ca2+]i is not a sufficient stimulus. In addition, ATP evoked a marked K+ release in the presence and absence of extracellular Ca2+, while in carbachol-stimulated cells. only a transient release of K+ was observed in the absence of extracellular Ca2+. The ATP-induced K+ release may be mediated by a mechanism independent of the opening of the Ca(2+)-sensitive K+ channels.

Appraisal of combination treatment for hepatocellular carcinoma: long-term follow-up and lipiodol-percutaneous ethanol injection therapy

Since 1988, 124 patients with hepatocellular carcinoma were treated in our departments. Among them, 31 cases treated by surgical resection and 30 cases administered a combination therapy (Lipiodol [Laboratoire Guerbet, Villepinte, France]-transcatheter arterial embolization [L-TAE] and lipiodol-percutaneous ethanol injection therapy [L-PEIT]) were analyzed retrospectively. The 1-, 3-, and 5-year survival rates were, respectively, 89.0%, 72.7%, and 63.6% for the surgical resection group and 93.3%, 72.8%, and 42.0% for the combination therapy group. The follow-up results at less than 4 years after the procedures revealed that the survival rate with the combination therapy was slightly better than that with the surgical treatment. However, in the subsequent 4 years, the survival rate of the combination therapy group decreased rapidly. The reasons for this deterioration were local recurrence and/or new primary lesions of hepatocellular carcinoma, mainly due to inappropriate ethanol injection. To achieve adequate and accurate injection of ethanol, a 10% volume of Lipiodol was mixed with the ethanol so that the location of the injected ethanol could be easily confirmed. The effectiveness of L-PEIT was thus confirmed by computed tomography, performed on the following day. Defective Lipiodol accumulation in the tumor and/ or neighboring tissues was able to be corrected by additional ethanol injections. With this L-PEIT technique, the tumor necrosis rate is now improving. Therefore, a better prognosis is expected.

Peptides derived from cardiovascular G-protein-coupled receptors induce morphological cardiomyopathic changes in immunized rabbits

An experimental model of early-stage cardiomyopathy was created by immunizing rabbits for 1 year with synthetic peptides corresponding to the sequence of the second extracellular loop of either beta-adrenoceptors or M2-muscarinic receptors. Thirty male rabbits were used and divided into three groups: a control group (n = 10), a group immunized with the peptide corresponding to the beta-adrenoceptor (beta 1 group) (n = 10) and a group immunized with the peptide corresponding to the M2-muscarinic receptor (M2 group) (n = 10). If the sera from both groups of immunized rabbits high-titres of anti-peptide antibodies were found throughout the study period but not in the sera from control rabbits or in the preimmune sera of immunized rabbits. No significant cross-reaction with peptides other than those used for immunization was found. The myocardial receptor density of both immunized groups displayed a strong trend toward receptor up-regulation. This was significant in the beta 1 group but not in the M2 group. Both groups of immunized rabbits displayed significantly enlarged ventricles and thinner walls, as compared with the control group. However, in contrast to the beta 1 group, which showed enlarged cavities in both left and right ventricles, the M2 group was mainly affected in the right ventricles. Moreover, morphological examinations of the hearts of rabbits from both immunized groups demonstrated focal myofibrillar lysis, loss of myofilament, mitochondrial swelling and condensation, sarcoplasmic vacuolation, deposition of dense granules in the sarcoplasm and the myofibrils. One of the sex control rabbit hearts which were examined showed mild degenerative changes in the myocardium and scant mononuclear cell infiltration. However, when all the control rabbit hearts were examined by electron microscopy, no significant alterations were found. These results suggest that immunization by peptides, corresponding to the target sequences for anti-receptor autoantibodies in idiopathic dilated cardiomyopathy, induces morphological changes in the heart similar to those found in the human disease.

Beneficial effects of amlodipine in a murine model of congestive heart failure induced by viral myocarditis. A possible mechanism through inhibition of nitric oxide production

BACKGROUND

Although calcium channel blockers have not been shown to be beneficial for the treatment of patients with heart failure, a recent clinical trial demonstrated a favorable effect of amlodipine on the survival of patients with heart failure resulting from nonischemic dilated cardiomyopathy. We investigated the effects of amlodipine on a murine model of congestive heart failure induced by the M variant of encephalomyocarditis virus (EMCV).

METHODS AND RESULTS

Four-week-old male DBA/2 mice were inoculated with EMCV and administered amlodipine, diltiazem, or vehicle PO for 2 weeks. The heart weight-to-body weight ratio and the histopathological grades of myocardial lesions were significantly lower and survival was significantly increased in the amlodipine-treated group (P < .01, P < .05, and P < .05, respectively) than in the control group. In vitro, amlodipine added to murine J774A.1 macrophages concomitant with EMCV inhibited nitrite formation in a concentration-dependent manner, but diltiazem did not. Furthermore, NG-monomethyl-L-arginine, an inhibitor of NO synthesis, decreased myocardial lesions significantly in this murine model. Immunohistochemistry revealed that the number of cells stained with antibody against an inducible NO synthase decreased significantly in the amlodipine-treated group compared with that in the control group (P < .01).

CONCLUSIONS

Amlodipine appears to have a protective effect against myocardial injury in this animal model of congestive heart failure. The therapeutic effect of amlodipine may be in part resulting from inhibition of overproduction of NO.

Prolongation of murine cardiac allograft survival with vesnarinone

Vesnarinone is a non-glycoside positive inotropic drug that has immunomodulating actions. In the present study, the effects of vesnarinone on both cardiac allografts and lymphocytes were investigated. First, in a mouse model of primary vascularized heterotopic cardiac transplantation, the oral vesnarinone treatment at a dose of 50 mg/kg/day prolonged median graft survival time significantly as compared with the vehicle-treated control. Histopathological examination revealed that cellular infiltration and interstitial edema were less prominent in the vesnarinone-treated than in the vehicle-treated allografts. The plasma concentrations of vesnarinone in mice treated with a single dose of 50 mg/kg were within the range of clinical relevance. To clarify the mechanism of action, in vitro studies were performed. The generation of specific cytotoxic T lymphocytes in mixed lymphocyte culture was significantly suppressed by the treatment with vesnarinone, especially at 3 and 10 microg/ml. The production of interferon-gamma in the co-culture was also suppressed by 10 microg/ml vesnarinone. However, the level of cyclic adenosine monophosphate was not significantly affected by vesnarinone at 10 microg/ml. The results suggest that vesnarinone acts beneficially on rejecting cardiac allografts through its lymphocyte-suppressive property, although this property may not be closely associated with the inhibiting action of the drug on the cyclic adenosine monophosphate-phosphodiesterase enzyme.

Airway epithelial cells produce stem cell factor

Airway epithelial cells modulate the inflammatory response in asthmatic, allergic and fibrotic lung diseases through the secretion of cytokines that regulate the movement and activation of inflammatory cells. Mast cells play an important role in the pathogenesis of these lung diseases. In this study we report that normal airway epithelial cells express stem cell factor which is a critical mediator of mast cell growth and differentiation and that transforming growth factor-beta inhibits secretion of stem cell factor by airway epithelial cells.

[In situ detection of Epstein-Barr virus in the non-neoplastic gastric glands and infiltrated lymphocytes]

Recently, clonal EBV-DNA and/or EBV-encoded small RNA(EBER1) have been detected in some gastric carcinomas. We reported the first observation of EBV infection in gastric glands with intestinal metaplasia, and characterized the EBV-infected lymphocytes which infiltrated in gastric mucosa. To determine the cellular location of EBV, EBER1 in situ hybridization(ISH) with an EBER1 oligonucleotide probe was applied to paraffin sections of the non-neoplastic gastric mucosa in 80 cases of gastric carcinoma and 49 cases of gastric ulcer. Not only was EBER1 expression detected in the nucleus of gastric cancer cells(5 cases) but also in non-neoplastic gastric epithelial cells(3 cases) and in infiltrated lymphocytes(40 cases). A single or a few shedding non-neoplastic epithelial cells in 2 cases of EBV-associated gastric cancer showed EBER1 expression. In one case, EBER1 was observed in all of the epithelial cells of a few gastric glands with intestinal metaplasia, suggesting that the stem cells of the metaplastic gastric glands were infected with EBV. EBV DNA was also detected in the EBER1-positive metaplastic glands scratched from the paraffin section by a single cell PCR method with a BamHI W primer pair. However, immunohistochemical examination showed that these metaplastic glands lacked expression of EBNA2 and LMP-1. The observation of these rare EBV-infected metaplastic glands reinforces the pre-transformation EBV infection hypothesis for EBV-associated gastric carcinoma. The double staining using ISH and immunohistochemistry revealed that EBER1 positive lymphocytes showed a B cell marker of L26(< 50%) but not T cell markers of UCHL1 and OPD4.

Immunomodulation: a new horizon for medical treatment of heart failure

Recently, the intriguing possibility has been raised that heart failure may be mediated by the biological effects of cytokines. Indeed, we found elevation of plasma concentrations of various cytokines in patients with myocardial disease. We also detected positive tumor necrosis factor (TNF-alpha) immunoreactivity in right atrial tissues obtained during surgery from patients with severe heart failure. Therefore, we postulated that some aspects of heart failure may be related to non-lethal down-modulation of cardiac function by immune cells and their cytokines. Testing this hypothesis in an experimental model of murine myocarditis, we found that injection of recombinant human TNF-alpha increased mortality of the animals infected with myocarditis virus. The anti-TNF-alpha monoclonal antibody improved survival and attenuated the myocardial lesions. Whereas, administration of recombinant human IL-2 in the acute viremic stage increased survival rate, and resulted in less intense pathological changes in the myocardium while in the subacute aviremic stage, the same amount of IL-2 reduced survival rate and exacerbated severity of the disease. Therefore, cytokine release may initiate a beneficial inflammatory and immune response in the acute phase of the disease process, but the continued induction of cytokines and the enhanced natural killer (NK) cell activity in the later stage are no longer protective. Vesnarinone, a recently synthesized inotropic agent which has proved to benefit patients with congestive heart failure by improving prognosis, also increased the survival of individual subjects in the above-mentioned murine model of heart failure. Cytotoxicity of NK cells obtained from the virus infected animals was substantially reduced when treated with vesnarinone. Vesnarinone also inhibited production of TNF-alpha and other cytokines from stimulated human lymphocytes and cultured murine splenocytes. We conclude, therefore, that inhibition of NK cell activity and suppression of cytokine production appear to be important immunological defense mechanisms which could contribute to the observed salutary effects of vesnarinone in the treatment of chronic heart failure. More broadly, immunomodulation could pave the way for a new frontier in the management of heart failure.

Tetrahydrobiopterin biosynthesis enhanced by lipopolysaccharide stimulation in murine neuroblastoma cell line N1E-115

We investigated for the first time the effect of lipopolysaccharide and the signal transduction pathway on the biosynthesis of tetrahydrobiopterin [(6R-L-erythro-1',2'-dihydroxypropyl) -2-amino-4-hydroxy-5,6,7,8-tetrahydropteridine], the cofactor for the enzymatic hydroxylation of the aromatic amino acids, in the murine neuroblastoma cell line N1E-115, which synthesizes tetrahydrobiopterin constitutively. Activation of N1E-115 cells with 1 microgram/ml lipopolysaccharide resulted in statistically significant increases in both intracellular tetrahydrobiopterin contents and the activity (Vmax) of GTP cyclohydrolase I, a rate-limiting enzyme in tetrahydrobiopterin de novo biosynthesis. Following simultaneous addition of the inhibitors of protein tyrosine kinases and GTP-binding proteins into serum-free culture media with lipopolysaccharide, we analyzed the transduction pathway of lipopolysaccharide signal toward the tetrahydrobiopterin biosynthetic system in N1E-115 cells. Our data indicate the following conclusions: (a) Protein tyrosine kinase systems are involved in mediating lipopoly-saccharide signal to tetrahydrobiopterin production, and (b) there may be a cross-talk between GTP-binding protein and the protein tyrosine kinase system in mediating lipopolysaccharide signal. These observations suggest that a neuronal cell such as N1E-115, which barely expresses CD14 on its cell surface, responds to lipopolysaccharide like macrophages and monocytes in the absence of soluble CD14.

Primary human fibroblasts induce diverse tumor invasiveness: involvement of HGF as an important paracrine factor

Fibroblasts have been considered to play an important role in tumor progression. In order to evaluate the contribution of fibroblasts to tumor invasion, TE2-NS, an esophageal cancer cell line, was cultured on collagen gel containing primary fibroblasts derived from normal esophageal submucosa or cancerous tissues of seven esophageal cancer patients. TE2-NS showed diverse invasiveness into the underlying gel containing fibroblasts, but did not invade the gel not containing fibroblasts. The invasiveness of TE2-NS, which expressed hepatocyte growth factor (HGF) receptor, was well-correlated with the concentration of HGF in conditioned medium. Administration of neutralizing antibody against HGF effectively suppressed the invasion, but application of recombinant HGF without fibroblasts induced little invasion into the gel. Fibroblasts from non-cancerous tissue generally secreted a larger amount of HGF and induced tumor invasion to a greater extent than those from cancer tissue, with large diversity. Interestingly, HGF secretion of fibroblasts from non-cancerous tissue was stimulated by co-culture with TE2-NS in two lines, but not in the other four. These results indicate that HGF is an important paracrine factor which induces tumor cell invasion, and the diversity of HGF production by fibroblasts might suggest different potentiality to induce tumor invasion among patients.

Decreased E-cadherin expression is associated with haematogenous recurrence and poor prognosis in patients with squamous cell carcinoma of the oesophagus

Reduced expression of E-cadherin is associated with tumour invasiveness and metastasis. To elucidate whether E-cadherin expression correlates with clinical outcome in patients with oesophageal cancer, 62 patients were investigated immunohistochemically using an anti-E-cadherin monoclonal antibody (HECD-1). Eight patients had normal levels of expression in the tumour, 25 had tumours that expressed high levels (50 per cent or more tumour cells staining positive for E-cadherin) and 29 had tumours expressing low levels (less than 50 per cent of cells expressing E-cadherin). Patients with normally expressing tumours had a better prognosis at 3 years than those with low-expressing tumours (P < 0.05). Postoperative death was correlated significantly with lymphatic invasion, lymph node metastasis, E-cadherin expression and depth of invasion (P < 0.05). Furthermore, haematogenous recurrence was correlated with E-cadherin expression (rs = 0.38, P < 0.01) and blood vessel invasion (rs = 0.28, P < 0.05). These results suggest that evaluation of E-cadherin immunoreactivity may predict haematogenous recurrence and poor prognosis in patients with oesophageal cancer.

[Intra-arterial infusion chemotherapy for liver metastases from breast cancer]

Twelve patients with liver metastases of breast cancer were treated with hepatic arterial infusion chemotherapy using 20-30 mg/body of epi-adriamycin (epi-ADM) every 2 weeks and continuous infusion of 250 mg/body/day of 5-fluorouracil (5-FU). All patients were followed by systemic chemo-endocrine therapy with oral administration of 600-1,200 mg/day of me droxyprogesterone acetate (MPA) alone or with 600-800 mg/day of 5'-deoxy-5-flurouridine (5'-DFUR). The response rate was 41.7% (5/12 cases). Duration of response was 2-28 months (mean 10 months). At one year, the survival rate was 46.8% (Kaplan-Meier method). As for side effects, gastrointestinal disturbance, bone marrow depression and alopecia were mild. These results suggest that hepatic arterial infusion therapy in combination with MPA is safe and effective for controlling liver metastases of breast cancer.

Use of chloride blockers: a novel approach for cardioprotection against ischemia-reperfusion damage

We examined whether the chloride channel blockers anthracene-9-carboxylic acid (9-AC) and 4-acetamide-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) exert protective effects against myocardial ischemia-reperfusion damage. In isolated guinea pig ventricular cells, 9-AC (200 microM), but not SITS (100 microM), inhibited the chloride current induced by isoproterenol. Electrical and mechanical activities and intracellular pH of arterially perfused guinea pig right ventricular preparations were recorded with an intracellular microelectrode, a force transducer and a pH-sensitive fluorescent probe, respectively. The preparations were subjected to 30 min of no-flow ischemia, with or without 9-AC (100 microM) or SITS (10 microM), followed by reperfusion. No-flow ischemia produced decreases in action potential amplitude and duration, and the contractile force was completely abolished. Although the changes in electrical parameters were reversed upon reperfusion, the contractile force recovered only to about 50% of preischemic values. 9-AC and SITS had no inhibitory effect on contractile force under normal conditions and during ischemia but significantly improved the recovery of contractile force upon reperfusion to about 80% of preischemic values. Both 9-AC and SITS showed significant inhibition of the ischemia-induced abbreviation of action potential duration. Other parameters were not affected by 9-AC or SITS. During ischemia, intracellular pH showed a transient small increase followed by a sustained decrease, which was completely recovered upon reperfusion. The decrease in pH during ischemia was attenuated by 80% in SITS- but not 9-AC-treated preparations. Thus, we demonstrated that the chloride channel blockers 9-AC and SITS, which have no cardiosuppressive effects, exert protective effects against myocardial ischemia-reperfusion damage.

Characteristic distribution of circulating autoantibodies against G-protein coupled cardiovascular receptors in patients with idiopathic dilated and hypertrophic cardiomyopathy

Circulating autoantibodies against cardiovascular membrane receptors have been repeatedly demonstrated in a subgroup of sera of patients with idiopathic dilated cardiomyopathy. This short review summarizes the clinical findings on anti-receptor autoantibodies in patients with dilated cardiomyopathy.

[Brain CT and MRI findings in fat embolism syndrome]

To elucidate brain CT and MRI findings in fat embolism syndrome (FES), we retrospectively analyzed images from 5 patients with FES during the acute and subacute stages. Brain CT examinations demonstrated brain edema in 2 patients and transient spotty low density lesions in 2 patients. Three patients showed no abnormalities. Brain MRI, however, showed brain abnormalities in all patients during the acute stages. These were revealed as spotty high signal intensity lesions on T2WI, and some showed low intensity on T1WI. These spotty lesions were considered to reflect edematous fluid occurring as a result of the unique pathophysiological condition of FES. While the spotty high signal intensity lesions on T2WI were distributed in the cerebrum, cerebellum, brain stem, thalamus, basal ganglia, internal capsule and corpus callosum, cerebral and cerebellar spotty lesions were characteristically located along the boundary zones of the major vascular territories. This characteristic location might be induced by a hypoxic brain condition in FES because the numerous fat globules present in this condition can block entire brain capillaries. This characteristic signal location on T2WI is a useful indicator for differentiating FES from the primary intra-axial brain injury in patients with multifocal trauma.