Tumor removal enhances immunity induced by B7.1

Costimulation of tumor T cells by B7.1 has been shown to be important for eliciting cell-mediated anti-tumor immunity. We constructed a stable B7.1 gene transfectant of a poorly immunogenic murine sarcoma, Moloney murine sarcoma virus-induced tumor cell line (MMSV). This transfectant, MMSV-B7.1, failed to produce any tumor development in syngeneic mouse models. When MMSV-B7.1 was simultaneously injected with wild-type MMSV, about half of the coinjected mice remained tumor free and displayed an increase in T cell population, upregulation of the mRNA level of various cytokines such as IL-4, IL-5, IL-10, IL-13, IL-15 and IFN-gamma, and complete rejection of reinjected MMSV. To investigate whether MMSV-B7.1 demonstrates any vaccinal effect, the transfectant was injected following the surgical removal of the primary tumor mass. Following a re-challenge with wild-type MMSV, all vaccinated mice maintained their tumor free status and displayed a rapid recovery of down-regulated cytokine levels. The results suggest that B7.1 vaccination after tumor removal might be useful for the prevention of tumor recurrence.

Changes in the E-cadherin-catenin complex expression in early and advanced gastric cancers

BACKGROUND/AIM

In various human cancers, dysfunction of the E-cadherin-catenin complex is associated with a decrease in cellular and tissue differentiation and with higher invasive and metastatic potentials. Since advanced gastric cancers are thought to evolve from early gastric cancers, we investigated whether differences of the E-cadherin-catenin complex expression can be observed between early and advanced gastric cancers.

METHODS

We have used an immunohistochemical technique to localize E-cadherin and alpha-, beta-, and gamma-catenins in 114 formalin-fixed, paraffin-embedded tissue blocks: 57 from patients with early gastric cancer and 57 from patients with advanced gastric cancer.

RESULTS

The immunoreactivity of E-cadherin and alpha-, beta-, and gamma-catenins was expressed by normal gastric epithelial cells with strong membranous staining at the intercellular border. Reduced expression of E-cadherin and alpha-, beta-, and gamma-catenins occurred in a considerable proportion of both cancer groups. However, no significant difference was seen between early and advanced cancer groups. In the early cancer group, reduced expression of E-cadherin and alpha-, beta-, and gamma-catenins correlated with diffuse type of cancer and poor differentiation. However, in the advanced cancer group, reduced expression of the three adhesion molecules, but not beta-catenin, correlated with diffuse type of cancer and poor differentiation. The expression of E-cadherin and alpha-, beta-, and gamma-catenins did not correlate with depth of invasion or lymph node metastases in both cancer groups.

CONCLUSION

These results suggest that alterations of the E-cadherin-catenin complex may be induced at an early stage of gastric tumorigenesis and may be associated with poorly differentiated and diffuse-type pathways in gastric tumorigenesis.

Completion of nucleotide sequence and generation of highly infectious transcripts to cucurbits from full-length cDNA clone of Kyuri green mottle mosaic virus

The nucleotide sequence of the genome of the type strain of Kyuri green mottle mosaic virus (KGMMV-C1) has been completely determined. The genome structure and sequence of the virus were compared to those of Yodo strain of KGMMV (KGMMV-Y). The genome of KGMMV-C1 is 6,514 nucleotides long consisting of 5' and 3' nontranslated regions (NTRs) and four open reading frames coding for 131 kDa and 189 kDa viral replicases, 28 kDa movement protein and 17 kDa coat protein. The nucleotide and amino acid sequences identities of the four encoded proteins and two NTRs between KGMMV-C1 and KGMMV-Y were 85.6% to 93.9% and 87.6% to 95.5%, respectively. Full-length cDNA of KGMMV-C1 was directly amplified by reverse-transcription polymerase chain reaction (RT-PCR) with a set of S'-end primer anchoring T7 RNA promoter sequence and 3'-end primer. This full-length RT-PCR product allowed RNA to be transcribed in vitro. The T7 promoter-anchored RT-PCR product was cloned and used as templates for transcription for plant inoculation test. Capped transcript RNAs transcribed from the full-length cDNA clone as well as capped transcript RNAs from the uncloned RT-PCR products were infectious and caused symptoms characteristic of KGMMV when mechanically inoculated to systemic host plants such as zucchini squash, cucumber and Nicotiana benthamiana. Transcript-derived progeny virus was indistinguishable from the wild-type virus with the same biological and biochemical properties. To our knowledge, this is the first report of the generation of a biologically active KGMMV clone, driven by the T7 promoter, that is highly infectious to cucurbitaceous plants.

Nonviral vector for efficient gene transfer to human ovarian adenocarcinoma cells

OBJECTIVE

Various strategies have been attempted to design efficient protocols for ovarian cancer gene therapy but there has been little progress in their clinical application. In this study, we formulated and evaluated a new cationic liposome prepared with dioleoyltrimethylaminopropane (DOTAP), 1,2-dioleoyl-3-phosphophatidylethanolamine (DOPE), and cholesterol (Chol) (DDC) for plasmid DNA transfer into ovarian cancer cells.

METHOD

The DDC liposome was prepared by mixing the DOTAP:DOPE:Cholin a 1:0.7:0.3 molar ratio using the extrusion method. Plasmid DNA (pEGFP-C1) and DDC were complexed at various weight ratios to find the optimum condition and the percentage of transfected cells was determined by selecting a green fluorescence protein (GFP) expressing cells in flow cytometry. The transfection efficiency of the DDC liposome was compared with 3[N-(N,N-dimethylaminoethylene) carbamoyl] cholesterol (DC-Chol)/DOPE liposome and commercially available lifopectin.

RESULTS

The optimal transfection of plasmid DNA was achieved at a 1:4 (w/w) ratio of DDC to DNA. The DDC/DNA complex exhibited higher transfection efficiency in human ovarian cancer cells (OVCAR-3 and SK-OV-3 cells) compared to that in other types of cell lines (NCI-NIH:522 and HepG2 cells). Flow cytometric analysis revealed that the DDC/DNA complex exhibited an over fourfold increase in GFP expression levels compared with DC-Chol/DOPE or lipofectin in OVCAR-3 cells. This result was further confirmed by confocal microscopy and RT-PCR analysis.

CONCLUSION

These results suggest that our newly formulated cationic liposome (DDC) appears to be a promising nonviral vector for treating ovarian adenocarcinoma because of its selective high gene transfer ability in ovarian cancer cells.

A planar amperometric creatinine biosensor employing an insoluble oxidizing agent for removing redox-active interferences

A planar microchip-based creatinine biosensor employing an oxidizing layer (e.g., a PbO2 film), where interfering redox-active substances are broken (i.e., oxidized) to redox-inactive products, was developed to facilitate the microfabrication of the sensor and to provide improved, reliable determination of creatinine in physiological samples. The feasibility of using hydrophilic polyurethanes in permselective barrier membranes for creatinine biosensors and the effect of adding a silanizing agent (adhesion promoter) on the sensor performance (e.g., sensitivity, stability, and lifetime) are described. The proposed creatinine microsensor with a three-layer configuration, i.e., enzyme, protecting, and oxidizing layers, exhibits good electrochemical performance in terms of response time (t95% = 98 s at 100-->200 microM creatinine change), linearity (1-1000 microM, r = 0.9997), detection limit (0.8 microM), and lifetime (approximately 35 days). The creatinine biosensor devised in a differential sensing arrangement that compensates the erroneous results from creatine is considered to be suitable for assay of serum specimens.

The role of fetal surgery in life threatening anomalies

The development and evolution of fetal surgery and the recognition of the fetus as a patient came from two sources. First, were those obstetricians and perinatologists who detected life threatening anomalies before birth, and re-described a hidden mortality arising from death in utero. Ultrasonography, color Doppler ultrasound and ultrafast fetal magnetic resonance imaging have since enhanced the accuracy of prenatal evaluation. Second, were those pediatricians responsible for treating newborn infants with extremely serious problems, and that appeared untreatable, although, it was believed that they could have been treated at an earlier stage of development. After the natural history of several correctable lesions had been determined and the selection criteria for intervention developed, fetal surgery emerged as a means of improving the overall morbidity and mortality rates.

Contralesional directional hypermetria associated with line bisection-specific ipsilesional neglect

Patients with contralesional neglect from right hemisphere injuries often fail to be aware of or respond to visual stimuli in the left hemispace. In contrast, other patients with right hemisphere damage rarely demonstrate behavior consistent with task-specific ipsilesional neglect (IN). We performed a series of experiments in a patient with IN on a line bisection task after a right frontal infarct. When asked to perform horizontal limb movements without visual feedback, the patient showed a leftward directional hypermetria. Similar performance was also observed during a representational production of a given distance without sensory input. These results suggest that IN is induced by a directional hypermetria resulting from disruption of the motor-intentional system.

The prognosis of stage IV gastric carcinoma patients after curative resection

BACKGROUND/AIMS

In the UICC staging system, stage IV contains not only those patients with distant metastasis but also patients with far-advanced T and N status but without distant metastasis. We investigated the prognostic factors of stage IV gastric carcinoma patients, without distant metastasis after curative resection and the role of surgery.

METHODOLOGY

One hundred and ninety stage IV gastric carcinoma patients, without distant metastasis were reviewed after curative resection in our hospital from January 1987 to December 1996.

RESULTS

Male sex, distal third location, diffuse or infiltrative type and histologically undifferentiated type were common. Of the 190 patients, 52 (27.4%) patients lived more than 3 years. The lymph node ratio (positive lymph node/retrieved lymph node) and combined resection independently affected survival (P = 0.0013, 0.0061, respectively). The perigastric lymph node ratio was well correlated with overall lymph node ratio (r = 0.794, P < 0.001).

CONCLUSIONS

With the involvement of an adjacent organ and knowing the perigastric lymph node ratio, the surgeon can decide upon the extent of dissection and postoperative treatment. However, a prospective study is warranted.

DNA ploidy patterns in advanced gastric carcinoma; is it a clinically applicable prognosticator?

BACKGROUND/AIMS

The purpose of this study was to evaluate the prognostic significance of ploidy patterns as determined by flow cytometry in terms of clinical usefulness.

METHODOLOGY

270 patients with a diagnosis of advanced gastric carcinoma were studied with fresh specimens obtained from multiple site avoiding nonviable or nonneoplastic tissues by DNA flow cytometry. DNA ploidy and clinicopathologic factors were compared and survival was analyzed.

RESULTS

The mean age of the patients was 56.1 +/- 11.6 years (25-80 years). There were 195 males and 75 females. Aneuploidy was shown in 93 (35.9%) patients. Male sex and differentiated tumor were more frequent in aneuploidy than diploidy (P = 0.011, < 0.001, respectively). By univariate analysis, tumor location, size, extent of resection, curative resection, serosa invasion, lymph node involvement, and distant metastasis significantly affected survival but not aneuploidy. Significant independent prognostic factors by multivariate analysis were curative resection, serosa invasion and lymph node involvement (P = 0.0001, 0.0114, 0.0262, respectively).

CONCLUSIONS

DNA ploidy patterns of advanced gastric carcinoma are of limited clinical significance, therefore not a clinically applicable prognosticator.

Protein release microparticles based on the blend of poly(D,L-lactic-co-glycolic acid) and oligo-ethylene glycol grafted poly(L-lactide)

Bovine serum albumin (BSA), a model protein drug, was encapsulated with a microparticle based on the blend of poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactide)-g-oligo(ethylene glycol) (PLLA-g-oligoEG). Effects of PLLA-g-oligoEG in the blend on degradation, characteristic properties, and release behavior of the microparticle were studied. Drug loading efficiency increased with increase in the graft frequency of oligoEG in the graft copolymer in the blend. The release of BSA was found to be more efficient for microparticles based on the blend than on the PLGA, which is due to the faster protein diffusion through the swollen phase of the hydrogel-like structure. The microparticles based on the blend showed a slower degradation and a lower pH shift compared to that of PLGA.

A case of del(13)(q22) with multiple major congenital anomalies, imperforate anus and penoscrotal transposition

"13q-"syndrome is known to have widely variable manifestations, including retinoblastoma, mental & growth retardation, malformation of brain & heart, anal atresia, and anomalies of the face and limbs. Here we report a case of del(13)(q22) with multiple major congenital anomalies for the first time in Korea. The patient was born at 36(+4) weeks of pregnancy by caesarian section. Birth weight was 1490g. On examination the following features were noted: - imperforate anus, ambiguous genitalia (bifid scrotum, penoscrotal transposition, hypospadia), syndactyly of toes, absence of thumbs, abnormal facies (dolichocephaly, telecanthus, large low set ears, saddle nose, high arched palate, micrognathia). Neurocranial ultrasonography showed atrophy of the corpus callosum and multiple calcifications. He died at 14 days. Post-mortem autopsy findings showed cholestasis and fatty metamorphosis of liver, abnormal lobulation (Rt:2, Lt:1) and lymphangiectasis of the lung, VSD, ASD, PDA of heart, and acute tubular necrosis of kidney. Cytogenetic studies was confirmed to 46,XY,del(13) (q22) by Giemsa banded chromosomes from peripheral blood lymphocytes.

Inhibition of tumor growth and metastasis by Korean mistletoe lectin is associated with apoptosis and antiangiogenesis

The mistletoe lectins are major active components in the extract of European mistletoes that have been widely used in adjuvant chemotherapy of cancer. This study was performed to investigate the mechanism of anticancer and antimetastatic activity of the purified Korean mistletoe lectin (Viscum album L. coloratum agglutinin, VCA). C57BL6 mice inoculated with B16-BL6 melanoma cells and treated with VCA were assessed for survival and metastasis. The induction of apoptosis of B16-BL6 cells by VCA was investigated by morphological changes, DNA fragmentation characteristics, and cell cycle analysis. The antiangiogenic activity of VCA was also measured by the CAM (choriallantoic membrane) assay. Length of survival of mice was increased and lung metastasis was inhibited by VCA. Treatment of cells with VCA resulted in growth suppression, nuclear morphological changes, DNA fragmentation, and an increased fraction of cells in sub-G1 consistent with apoptosis. Antiangiogenesis of VCA was assessed by CAM assay, where vessel growth induced by fat emulsion was decreased. These results suggest that VCA inhibits tumor growth and metastasis by increasing apoptosis and inhibiting angiogenesis.

Biliary atresia associated with meconium peritonitis caused by perforation of small bowel atresia

BACKGROUND/PURPOSE

This report describes our experiences with 5 cases of biliary atresia associated with meconium peritonitis caused by perforation of small bowel atresia.

METHODS

A review of medical records was undertaken in an effort to recognize cases of biliary atresia associated with meconium peritonitis.

RESULTS

Five patients of 171 with biliary atresia (2.9%) were detected to have meconium peritonitis caused by perforation of small bowel atresia. The biliary atresia was not suspected during the initial operation for meconium peritonitis. Total parenteral nutrition (TPN) made it difficult to make an early differential diagnosis of biliary atresia because of the presence of TPN-associated cholestatic jaundice, and the Roux-en-Y limb used for hepatic portoenterostomy could not be made long enough to prevent cholangitis caused by preexisting short bowel. The main complications were severe, intractable cholangitis, short bowel syndrome with malnutrition; TPN-associated liver injury; and wound problems. Two patients died of ascending cholangitis, 1 patient of liver failure that was exacerbated by TPN-associated liver injury, and 1 patient is awaiting a liver transplant. Only 1 patient is in good health, being anicteric and showing normal growth and development.

CONCLUSIONS

Biliary atresia is evidently closely associated with meconium peritonitis caused by perforation of small bowel atresia. The management of these patients is more difficult than that of patients with the usual form of biliary atresia, because of the necessity for a long period of TPN and the combined short bowel syndrome. The ideal management of these conditions has yet to be determined.

Fistula-in-ano in infants: is nonoperative management effective?

PURPOSE

Recently, a number of studies have reported positive results from the nonoperative management of fistula-in-ano in infancy, although it has not been of use in all patients. The purpose of this study was to discern the effective treatment methods of fistula-in-ano in infants.

METHODS

A retrospective review was done of 310 children who required operative management for fistula-in-ano or perianal abscess between January 1991 and July 2000. Eighteen patients displayed an onset of symptoms at less than 1 year of age and a duration of symptoms longer than 12 months. The authors analyzed these patients' medical records.

RESULTS

All patients were boys. The mean duration of the symptoms was 26.6 +/- 27.5 months. Fourteen patients had shown an onset of symptoms at less than 6 months of age. The longest duration was 10 years. The patients showed conservative periods of over 12 months because their parents did not want them to undergo surgery. The disease in these patients followed 2 patterns. One (6 patients) was an onset of symptoms followed by a silent fistula-in-ano state. The other (12 patients) was an onset of symptoms followed by an intermittent relapse of inflammation. All patients underwent fistulotomy, and none of them had recurrent fistula during the follow-up period.

CONCLUSIONS

Although the advantages of a nonoperative management of fistula-in-ano in infants include the avoidance of general anesthesia and surgical intervention, the lesions cannot be cured by a period of conservation. Surgical management is more effective in respect to the time factor.

Estrogen attenuates cell death induced by carboxy-terminal fragment of amyloid precursor protein in PC12 through a receptor-dependent pathway

In the present study, we investigated effects of estrogen on cell death induced by carboxy-terminal fragment of amyloid precursor protein (CT), a candidate causative substance in the pathogenesis of Alzheimer's disease. 17 beta-Estradiol attenuated CT-induced cell death in PC12 cells, whereas 17 alpha-estradiol, nonestrogenic stereoisomer, did not exert any significant protective effect on CT-induced cell death. These results suggest that protective effects of estrogen may be mediated by estrogen receptor (ER) in PC12 cells. To confirm the results, we determined the effects of tamoxifen, an estrogen receptor antagonist. Tamoxifen blocked the protective effects of 17 beta-estradiol, although it did not affect those of 17 alpha-estradiol. Overall, it might be thought that the protective effect of estradiol on CT-induced cell death is achieved by hormonal properties mediated through the estrogen receptor rather than the structural properties as a reducing agent.

Changes in premenstrual symptoms in women with schizophrenia: a prospective study

OBJECTIVE

We investigated whether the psychiatric symptoms and clinical features of schizophrenia change during the premenstrual phase in female patients.

METHODS

We observed 30 female schizophrenic inpatients over one menstrual cycle. All subjects met DSM-IV criteria for schizophrenia, and all had a regular menstrual cycle. All subjects completed the Daily Rating Form (DRF) every evening, and one psychiatrist rated the subjects (using the Brief Psychiatric Rating Scale [BPRS]) once during each of the three menstrual phases (premenstrual, menstrual, and postmenstrual). Serum levels of estradiol (E2) and progesterone were measured on the fifth to seventh day of both the premenstrual and postmenstrual phases. Data from the 24 subjects who completed the DRF correctly and completely were used for statistical analysis.

RESULTS

The mean total BPRS score for the 24 subjects was highest in the premenstrual phase and lowest in the postmenstrual phase, and a statistically significant difference was found among the three menstrual phases. Mean subtotal BPRS scores showed statistically significant differences among the three menstrual phases in anxiety/depression and withdrawal/retardation, but not in the psychotic symptom subscales. Mean serum E2 level showed a trend of increasing from the premenstrual phase to the postmenstrual phase. However, there was no significant correlation between DeltaBPRS and DeltaE2. When the criterion of 30% change was applied, the DRF items of depressed mood, anxious/nervous/restless, hostile/aggressive, and less/impaired work showed high frequencies of change in the premenstrual phase. Somatic items of abdominal pain, breast pain, and headache showed significant change with the 30% change rule on the DRF. On both the BPRS and DRF scores, premenstrual change of affective and behavioral symptoms was prominent, whereas the change of psychotic symptoms was minimal on the BPRS. In addition, in the premenstrual phase, there was a statistically significant correlation between the total BPRS score and the mean total DRF score. There was no correlation between premenstrual change in symptoms and hormonal levels of E2, progesterone, and the estradiol/progesterone (E/P) ratio.

CONCLUSIONS

The findings of this study suggest that premenstrual exacerbation of schizophrenic symptoms in female patients may not be a worsening of the schizophrenic symptoms but a concurrence of affective, behavioral, and somatic symptoms.

Cross-linking of MHC class II molecules with anti-MHC class II antibody or epitope peptide prevents resting B lymphocyte differentiation by inhibiting NF-kappaB-dependent gene expression

To understand the mechanism(s) involved in anti-MHC class II antibody-mediated inhibition of B lymphocyte differentiation, we investigated the influence of anti-MHC class II antibody treatment on the gene expression of IL-6 in resting B lymphocytes, which had been known to be one of the most important cytokines involved in B cell physiology. The level of the IL-6 mRNA expression in the LPS-stimulated resting B cells was remarkably reduced by treatment of the corresponding anti-MHC class II antibodies. The inhibition was exerted in haplotype-specific and dose-dependent manners. Similarly, MHC class II-restricted epitope peptides, when applied as a dimer form, revealed haplotype-specific and dose-dependent inhibitory effects on the IL-6 gene expression by the LPS-stimulated B cells. In addition, treatment of the anti-MHC class II antibody and MHC class II-restricted epitope peptide inhibited, in haplotype-specific and dose-dependent manners, the activation of NF-kappaB, which had been known to be one of the critical transcription factors involved in the IL-6 gene expression. Interestingly, however, exogenous addition of the recombinant IL-6 did not reverse this inhibitory effect by the anti-MHC class II antibody. These results suggest that conjugation of the MHC class II molecules by the anti-MHC class II antibody inhibited B cell differentiation, possibly through the interruption of signaling pathways leading to the IL-6 gene expression via NF-kappaB activation in B lymphocytes.

Therapeutic effect of bee venom in sows with hypogalactia syndrome postpartum

The objective of this study was to determine the clincotherapeutic effect of whole bee venom in hypogalactic sows postpartum. Sows after parturition were assigned to treated and nontreated control groups. In the treated group, 22 sows were bee acupunctured once a day for 3 consecutive days. Honeybees (Apis mellifera L.) for bee acupuncture were about 15 days after metamorphosis. One live bee was used to sting the acupoints known as Yang-ming (ST-18, 1.5 cm lateral to the base of the last 2 pairs of teats) and Jiao-chao (GV-1, at the indentation between the base of tail and the anus). In the control group, 20 sows were intramuscularly injected with a standard dosage of penicillin G (400,000 IU/head) once a day for 3 consecutive days. At post-treatment, 85.0% of the drug-treated control and 90.9% of the bee venomtreated group recovered from hypogalactia syndrome. The advantages of apitherapy were that the patients did not have stress because they were not restrained for a long period. The result suggested that apitherapy using bee venom is an effective treatment for sows with hypogalactia syndrome postpartum.

Functional magnetic resonance imaging during pantomiming tool-use gestures

The purpose of this study was to identify the functional fields activated in relation to gestural movements. Using functional magnetic resonance imaging (fMRI), we mapped brain activity in ten right-handed, normal volunteers during activation and control tasks. The activation condition consisted of pantomiming tool-use gestures with either the left hand or right hand, whereas the control condition comprised repetitive, oppositional movements between thumb and index finger. Activated cortical regions were highly lateralized to the left hemisphere during pantomiming of tool use regardless of hand used. Praxis with either hand commonly activated the superior parietal lobule, supplementary motor area, premotor area of the left hemisphere, and cerebellar vermis. However, minimal activation occurred in the inferior parietal lobule, which has been known to be a critical area for praxis generation. Compared with left-hand praxis, right-hand praxis exhibited additional activation in the left putamen and posterior part of the left inferior temporal region. Our findings concur with neuropsychological observations that the left hemisphere in right-handers mediates programming and executing skilled movements and that, within the left hemisphere, praxis is predominantly subserved by the parietal lobe, supplementary motor area, and premotor area. However, unlike previous lesion studies, the results of our fMRI study suggested that the superior parietal lobule more likely than the inferior parietal lobule play an important role in gesture production.

Occlusive myocardial infarction: investigation of bis-gadolinium mesoporphyrins-enhanced T1-weighted MR imaging in a cat model

PURPOSE

To test whether bis-gadolinium mesoporphyrins-enhanced magnetic resonance (MR) imaging can accurately depict irreversibly damaged myocardium in occlusive myocardial infarction.

MATERIALS AND METHODS

Ten cats were subjected to 90 minutes of occlusion of the left anterior descending coronary artery. Bis-gadolinium mesoporphyrins-enhanced T1-weighted MR imaging was performed in the cats for 6 hours. Histopathologic examinations with 2'3'5-triphenyl tetrazolium chloride (TTC) staining and electron microscopy were performed on the resected specimens. The time course and pattern of signal intensity enhancement were evaluated. The size of the infarcted myocardium was estimated on the MR images by measuring the size of the signal intensity-enhanced area.

RESULTS

In eight of 10 cats, it was impossible to distinguish infarcted myocardium from normal myocardium at visual inspection of T1-weighted MR images. The contrast ratio between infarcted and normal myocardium did not increase significantly over time. In one of the two remaining cats, a doughnut pattern of signal intensity enhancement was noted. The other cat showed intensely homogeneous enhancement of infarcted myocardium at MR imaging. The size of the area of signal intensity enhancement at MR imaging in these two cats was accurately mapped to that of the infarction on the TTC-stained specimens.

CONCLUSION

Occlusive myocardial infarction cannot be accurately detected at bis-gadolinium mesoporphyrins-enhanced MR imaging.