[Two cases of anti-nuclear matrix protein 2 antibody-positive dermatomyositis sine dermatitis with severe diffuse subcutaneous edema and dysphagia]

Case 1 involved a 68-year-old woman who was admitted to our hospital because of muscle weakness, diffuse subcutaneous edema, dysphagia, and an elevated serum creatine kinase level that had worsened within the previous month. Case 2 involved a 78-year-old woman who was admitted to our hospital because of muscle weakness, bilateral shoulder pain, diffuse subcutaneous edema, and dysphagia that had gradually worsened during the past 5 months. Both patients showed severe diffuse subcutaneous edema and dysphagia and underwent enteral tube feeding. Although they had no skin lesions consistent with dermatomyositis, muscle biopsies showed myxovirus resistance protein A (MxA) expansion, and blood tests showed positivity for anti-nuclear matrix protein 2 (anti-NXP-2) antibody. Therefore, both presents were diagnosed with anti-NXP-2 antibody-positive dermatomyositis sine dermatitis (DMSD). Anti-NXP-2 antibody-positive dermatomyositis has been reported to be closely associated with DMSD, severe edema and dysphagia. Differential diagnosis for patients who develop myositis with severe subcutaneous edema and dysphagia should include anti-NXP-2 antibody-positive dermatomyositis, and it is important to consider measurement of anti-NXP-2 antibody.

Serial Magnetic Resonance Imaging and Magnetic Resonance Angiographic Findings of Reversible Cerebral Vasoconstriction Syndrome Associated with Postpartum

We report 2 cases of reversible cerebral vasoconstriction syndrome (RCVS) associated with postpartum. In case 1, a 26-year-old woman developed sudden-onset headache, nausea, and vomiting 1 h after an uncomplicated vaginal delivery. In case 2, a 27-year-old woman developed generalized seizures 9 days after an uncomplicated vaginal delivery. In both cases, initial angiographic studies showed no significant vasoconstriction; however, repeat studies revealed reversible vasoconstriction. Serial magnetic resonance imaging (MRI) revealed transient brain lesions during 6 months. RCVS remains poorly characterized, misdiagnosed, and under-recognized. Serial MRI and magnetic resonance angiographic findings may contribute to diagnosis of RCVS.

A case of type 1 facioscapulohumeral muscular dystrophy (FSHD) with restrictive ventilatory defect and congestive heart failure

[Background] Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscle disease characterized by asymmetric involvement of muscles in the face, upper extremity, trunk, and lower extremity regions, with variable severity. It was recently reported that restrictive respiratory involvement is more frequent and severe than previously recognized, while cardiac dysfunction other than arrhythmia is still considered extremely rare in FSHD. [Case report] A 59-year-old man presenting with marked muscle atrophy in the trunk and asymmetrical muscle atrophy in the legs was hospitalized because of dyspnea and edema in the face and limbs. Shortness of breath with body movement started from approximately 40 years of age. Muscle biopsy revealed myopathic change with mild to moderate variation in fiber size. The diagnosis of FSHD was made by D4Z4 contraction to three repeats on genetic testing. A pulmonary function test revealed a decline of forced vital capacity (FVC) and a preserved FEV1/FVC indicating restrictive ventilatory defect (RVD). Ultrasonic echocardiogram (UCG) showed diffuse left ventricular hypokinesis, ventricular septum thickening, pericardial effusion, and decreased ejection fraction (LVEF 30%). [Conclusion] Although restrictive ventilatory defect and congestive heart failure are uncommon in FSHD, respiratory and cardiac evaluation may be necessary in patients with FSHD.

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A 59-year-old man with FSHD was hospitalized for dyspnea and edema.

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Genetic testing revealed that he carried a D4Z4 reduced allele with three repeats.

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The pulmonary function test indicated restrictive ventilatory defect.

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Ultrasonic echocardiography indicated congestive heart failure.

Improvement of a decreased anti-oxidative activity by edaravone in amyotrophic lateral sclerosis patients

BACKGROUND

The free radical scavenger edaravone is a proven neuroprotective drug for patients with amyotrophic lateral sclerosis (ALS). Our objective was to evaluate the therapeutic effects of edaravone for oxidative stress and anti-oxidative activity in ALS patients.

METHODS

Twenty-two ALS patients with a disease duration of 2 years, treated by edaravone, and 25 control participants were evaluated according to their clinical scores, including ALS functional rating scale-revised (ALSFRS-R), and serum and cerebrospinal fluid (CSF) markers of oxidative stress dROM and anti-oxidative activity OXY.

RESULTS

Serum and CSF markers of anti-oxidative activity OXY were significantly decreased in ALS patients at pre-treatment compared with controls (^##p < .01), which was improved in the course of edaravone treatment. Both serum and CSF OXY were significantly correlated with ALS clinical scores including ALSFRS-R (*p < .05, **p < .01, ***p < .001). Furthermore, serum OXY at pre-treatment was significantly correlated with a change in the ALSFRS-R score in the sixth cycle of edaravone treatment (*p < .05).

CONCLUSIONS

The present study suggests significant correlations between anti-oxidative activity and ALS clinical severity, and the therapeutic efficacy of edaravone for decreased anti-oxidative activity in ALS.

The identified clinical features of Parkinson's disease in homo-, heterozygous and digenic variants of PINK1

To investigate the prevalence and genotype-phenotype correlations of phosphatase and tensin homolog induced putative kinase 1 (PINK1) variants in Parkinson's disease (PD) patients, we analyzed 1700 patients (842 familial PD and 858 sporadic PD patients from Japanese origin). We screened the entire exon and exon-intron boundaries of PINK1 using Sanger sequencing and target sequencing by Ion torrent system. We identified 30 patients with heterozygous variants, 3 with homozygous variants, and 3 with digenic variants of PINK1-PRKN. Patients with homozygous variants presented a significantly younger age at onset than those with heterozygous variants. The allele frequency of heterozygous variants in patients with age at onset at 50 years and younger with familial PD and sporadic PD showed no differences. [¹²³I]meta-iodobenzylguanidine (MIBG) myocardial scintigraphy indicated that half of patients harboring PINK1 heterozygous variants showed a decreased heart to mediastinum ratio (12/23). Our findings emphasize the importance of PINK1 variants for the onset of PD in patients with age at onset at 50 years and younger and the broad spectrum of clinical symptoms in patients with PINK1 variants.

Effect of intravenous immunoglobulin therapy on anti-NT5C1A antibody-positive inclusion body myositis after successful treatment of hepatitis C: A case report

Inclusion body myositis (IBM) is the commonest idiopathic inflammatory myopathy of older persons. Pathophysiological mechanism of IBM remains unknown; however, an association of IBM with chronic hepatitis C virus (HCV) infection and serum autoantibodies against skeletal muscle protein 5′-nucleotidase 1A (NT5C1A) has recently been reported. No effective treatment for IBM has yet been developed. We here present a 70-year-old man who was anti-NT5C1A antibody-positive in association with IBM and chronic hepatitis C. The initial treatment of ombitasvir/paritaprevir/ritonavir for his chronic hepatitis C was successful; however, his symptoms of IBM did not improve. On the contrary, his quadriplegic paralysis became more severe and he developed dysphagia. Next, steroid pulse therapy was initiated for IBM and, although his hyper-creatine phosphokinase-emia improved, his symptoms did not; indeed, they worsened. Subsequent intravenous immunoglobulin therapy (IVIg) resulted in obvious improvement in his dysphagia. Thereafter IVIg therapy was repeated at approximately 2-monthly intervals. His dysphagia remained improved for more than 1 year; however, his quadriplegia continued to progress slowly. Although IBM can reportedly be associated with hepatitis C, we inferred that there was no direct relationship between these conditions in our patient because his IBM did not improve after treatment of his hepatitis C. Although his IBM-associated quadriplegia did not improve, IVIg therapy did result in improvement in his dysphagia.

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Coexisting anti-NT5C1A antibody+ inclusion body myositis and chronic hepatitis C

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Symptoms of IBM did not improve with successful treatment of hepatitis C.

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Videofluoroscopic examination confirmed improvement in dysphagia with IVIg therapy.

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Repeated IVIg therapy resulted in persistent improvement in dysphagia over 1 year.

Spreading brain lesions in a familial Creutzfeldt-Jakob disease with V180I mutation over 4 years

BACKGROUND

We report a female patient with familial Creutzfeldt-Jakob disease with V180I mutation (fCJD with V180I), who was serially followed up with magnetic resonance imaging (MRI) and electroencephalogram (EEG) for up to four years.

CASE PRESENTATION

At 6 months after the onset, diffusion-weighted images (DWI) and fluid-attenuated inversion recovery (FLAIR) of brain MRI revealed an increased signal intensity in the bilateral frontal, temporal, and parietal cerebral cortex with left dominancy except for the occipital lobe. However, her follow-up MRI at four years showed the high-signal regions spreading to the occipital cerebral cortex in DWI and FLAIR images, and bilateral frontal cerebral white matter in FLAIR images. EEG showed a progressive and general slow high-voltage rhythm from 7-8 to 3-5 c/s over four years, without evidence of periodic synchronous discharge. These findings correspond to the symptom progression even after akinetic mutism at 18 months.

CONCLUSION

We suggest that serial MRI and EEG examinations are useful for early diagnosis of fCJD with V180I and for monitoring disease progression.

Abnormal response to sodium channel blockers in patients with Brugada syndrome: augmented localised wall motion abnormalities in the right ventricular outflow tract region detected by electron beam computed tomography

OBJECTIVE

To investigate the relation between the wall motion abnormalities and sodium channel abnormalities in cases of the Brugada syndrome.

DESIGN

Consecutive prospective case-control study in a single hospital.

SETTING

Tertiary referral centre.

PATIENTS

13 consecutive patients with Brugada syndrome and 13 age and sex matched control subjects.

INTERVENTIONS

Each subject underwent electron beam computed tomography (EBT) and a 12 lead ECG before and after disopyramide injection.

MAIN OUTCOME MEASURES

QRS width and the magnitude of ST segment elevation in the 12 lead ECG; wall motion by EBT.

RESULTS

After disopyramide, EBT revealed deterioration of focal wall motion abnormalities in the right ventricular outflow tract region in eight of the 13 patients (62%). Prolongation of the QRS width after disopyramide injection in lead V2, which usually reflects the electrical activity in right ventricular outflow tract region, was greater in these eight patients (p < 0.01) than in the other five patients, in whom wall motion did not change after disopyramide. The degree of augmentation of ST segment elevation did not differ significantly between the two groups

CONCLUSIONS

The deterioration of wall motion abnormalities in the right ventricular outflow tract region after disopyramide suggests the presence of functional abnormalities of the sodium channel. Some patients with Brugada syndrome may have arrhythmogenic substrates with abnormal responses to sodium channel blockers.

A histological study on the mechanism of epidermal nuclear elongation in electrical and burn injuries

Epidermal nuclear elongation is one of the most important signs for the diagnosis of electrical injury. In this study, we investigated the mechanism responsible for this phenomenon by comparing the findings from burn injuries and those from contusions. Electrical and burn injuries were made in the dorsal skin of rats using energy ranging from 100 to 790 joules for electrical injury, and 170-690 joules for burn injury. Contusions were also made by compressing the skin with a vice. In electrical and burn injuries, the dermis under the epidermal elongated nuclei was homogeneous and without empty spaces between collagen bundles and the number of dermal fibroblasts per 0.01 mm2 below the damaged epidermis decreased significantly (P < 0.05). The incidence of this change correlated with the depth of denatured dermal collagen fibres and in both types of injuries, dermal cells had no nuclear antigenicity for ubiquitin. The width of the injured epidermis with nuclear elongation decreased significantly (P < 0.05) and the elongated nuclei were parallel to the basal membrane. In electrical injury however, nuclear elongation occurred more frequently near the external root sheath. Nuclear elongation of fibroblasts and external root sheath cells was also found, but those of sebaceous gland cells were not detected. Epidermal elongated nuclei were also found in contusions. The evidence strongly suggests that epidermal nuclear elongation in electrical and burn injuries is due to dermal expansion by heat.

Complete genome sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7

The complete genomic sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7 which optimally grows at 80 degrees C, at low pH, and under aerobic conditions, has been determined by the whole genome shotgun method with slight modifications. The genomic size was 2,694,756 bp long and the G + C content was 32.8%. The following RNA-coding genes were identified: a single 16S-23S rRNA cluster, one 5S rRNA gene and 46 tRNA genes (including 24 intron-containing tRNA genes). The repetitive sequences identified were SR-type repetitive sequences, long dispersed-type repetitive sequences and Tn-like repetitive elements. The genome contained 2826 potential protein-coding regions (open reading frames, ORFs). By similarity search against public databases, 911 (32.2%) ORFs were related to functional assigned genes, 921 (32.6%) were related to conserved ORFs of unknown function, 145 (5.1%) contained some motifs, and remaining 849 (30.0%) did not show any significant similarity to the registered sequences. The ORFs with functional assignments included the candidate genes involved in sulfide metabolism, the TCA cycle and the respiratory chain. Sequence comparison provided evidence suggesting the integration of plasmid, rearrangement of genomic structure, and duplication of genomic regions that may be responsible for the larger genomic size of the S. tokodaii strain7 genome. The genome contained eukaryote-type genes which were not identified in other archaea and lacked the CCA sequence in the tRNA genes. The result suggests that this strain is closer to eukaryotes among the archaea strains so far sequenced. The data presented in this paper are also available on the internet homepage (http://www.bio.nite.go.jp/E-home/genome_list-e.html/).

A system for computer-assisted design of stent-grafts for aortic aneurysms using 3-D morphological models

A three-dimensional model was constructed from helical CT images for abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA). A stent-graft was designed and positioned endoluminally on the computer. One hundred and nine stent-grafts for 101 patients were designed by this method and deployed well in all patients. The design time was reduced from 4 to 0.5 hr.

Prostaglandin I(2)/E(2) ratios in unilateral renovascular hypertension of different severities

Differences between prostaglandins I(2) and E(2) in their renal synthesis and pathophysiological roles were investigated in unilateral renovascular hypertension of different severities in 18 patients: 6 with mild stenosis (<75% of the diameter) of the renal artery, 7 with moderate stenosis (75% to 90%), and 5 with severe stenosis (>90%). Before and after aspirin administration (10 mg/kg), renal venous and aortic plasma was assayed for 6-ketoprostaglandin F(1alpha) (instead of prostaglandin I(2)), prostaglandin E(2), and renin activity. In mild or moderate stenosis, the mean 6-ketoprostaglandin F(1alpha) level in renal venous plasma from the stenotic side was not different from that from the normal side or from aortic plasma. Prostaglandin E(2) levels and renin activity in such patients were higher on the stenotic side than on the normal side and higher in venous than in aortic plasma. Aspirin inhibited prostaglandin E(2) synthesis and suppressed renin release from stenotic kidneys and lowered blood pressure as the renin activity decreased in patients with mild or moderate stenosis. In severe stenosis, levels of 6-ketoprostaglandin F(1alpha) and prostaglandin E(2) were higher on the stenotic side than on the normal side and higher in venous than in aortic plasma. Aspirin inhibited the synthesis of both prostaglandins and suppressed renin release from the stenotic kidney. In patients with unilateral renovascular hypertension with mild or moderate stenosis of the renal artery, prostaglandin E(2), rather than I(2), seems to contribute to further acceleration of renin release. Prostaglandin I(2) may increase and participate in further renin release when the stenosis is severe.

Localized right ventricular morphological abnormalities detected by electron-beam computed tomography represent arrhythmogenic substrates in patients with the Brugada syndrome

AIMS

This study was designed to determine, using electron-beam CT, whether there are morphological abnormalities in patients with the Brugada syndrome and to elucidate the relationship between those abnormalities and arrhythmogenesis.

METHODS AND RESULTS

Twenty-six consecutive patients with the Brugada syndrome and 23 age- and gender-matched control subjects (controls) were evaluated for morphological abnormalities using electron beam CT. Electron beam CT demonstrated morphological abnormalities of the right ventricle in 21 (81%) of 26 patients, but in only two (9%) of 23 controls. The sites of morphological abnormalities were the right ventricular outflow tract area in 17 patients and the inferior wall of the right ventricle in four patients. Of the seven patients with monoform premature ventricular contractions recorded only in the acute phase, four of the five patients with premature ventricular contractions from the right ventricular outflow tract area had morphological abnormalities in the right ventricular outflow tract area, and the other two patients with premature ventricular contractions from the inferior wall of the right ventricle had morphological abnormalities in the inferior wall of the right ventricle.

CONCLUSION

The sites of morphological abnormalities detected by electron beam CT in patients with the Brugada syndrome were related to the origins of premature ventricular contractions recorded only in the acute phase, which may trigger ventricular fibrillation. These morphological abnormalities may be related to arrhythmogenic substrates in patients with the Brugada syndrome.

Action kinetics of a prothoracicostatic peptide from Bombyx mori and its possible signaling pathway

A prothoracicostatic peptide (PTSP), purified from the brains of Bombyx mori, was found to inhibit ecdysteroidogenesis in the prothoracic glands (PGs) of this insect. This peptide was active at inhibiting ecdysteroidogenesis in the PGs at concentrations higher than 23 nM and glands incubated in 230 nM PTSP in vitro exhibited maximum inhibition of ecdysteroid production. By incubating PGs in vitro at different incubation periods it was observed that the first statistically significant inhibitory effect occurred after 30 min incubation in the presence of PTSP. Transferral of PGs from a medium with PTSP to a medium without PTSP resulted in the resumption of ecdysteroid production. Statistically significant inhibition of ecdysteroid production by PTSP was observed only in day 6 and in day 3 PGs of the 5th instar. The extracts of day 6 glands incubated in the presence of PTSP did not contain elevated amounts of ecdysteroid relative to controls after the incubations, indicating that PTSP does not inhibit the secretion, rather the synthesis, of ecdysteroid in the PGs. The presence of PTSP completely blocked the increased ecdysteroid production via L-type Ca(2+) channel activation by S(-)*Bay K 8644. There was no inhibition of ecdysteroid production by PTSP with glands incubated in Ca(2+)-free medium. The combined results suggest that PTSP regulates ecdysteroid synthesis only during specific stages of the 5th instar through a mechanism that likely involves the blocking of Ca(2+) influx through voltage-sensitive Ca(2+) channels in the PG cells of B. mori.

An application of PCR-single strand conformation polymorphism to MN genotyping

A PCR-based genotyping of MN blood group system was investigated for DNA samples taken from a population of 409 northern Japanese. DNA fragment (257bp) including exon 2 of glycophorin A (GPA) gene, in which encodes the determinants of MN antigens, was specifically amplified. On the analysis of PCR-single-strand conformation polymorphism (PCR-SSCP) for M alleles, band patterns of M(G) and M(T) were easily discriminated each other. For N alleles, three band patterns were observed, and we tentatively named these alleles as N(1), N(2) and N(V). The N(1) allele appeared predominantly and N(2) had two base substitutions at 1st (C-->A) and 56th (C-->T) in exon 2 of N(1). The other N(V), which was detected from a pair of a mother and her child, possessed a single base substitution at 23rd (A-->G) in intron 2. The allele frequencies of M(G), M(T), N(1) and N(2) were 0.4450, 0.0978, 0.4303 and 0.0269, respectively. The polymorphism information content and the probability of paternity exclusion by this MN genotyping were estimated to be 0.5252 and 0.3219, respectively.

Estimation of myocardial perfusion and viability using simultaneous 99mTc-tetrofosmin--FDG collimated SPECT

This study was designed to elucidate the usefulness of crosstalk correction for dual-isotope simultaneous acquisition (DISA) with 99mTc-tetrofosmin and FDG in estimating myocardial perfusion and viability.

METHODS

Eighteen patients with coronary artery disease were studied. First, SPECT was performed with a low-energy high-resolution collimator after a single injection of 99mTc-tetrofosmin (single 99mTc-tetrofosmin). Second, PET and DISA with an ultra-high-energy collimator were performed after glucose loading and an injection of FDG. DISA was designed to operate with simultaneous 3-channel acquisition, and weighted scatter correction of crosstalk from the 18F photopeak to the 99mTc photopeak was performed by modification of an existing dual-window technique. The FDG SPECT images were compared with the images obtained by PET. Both crosstalk-corrected and uncorrected 99mTc-tetrofosmin images were generated and compared with the single 99mTc-tetrofosmin images.

RESULTS

Regional percentage uptake of FDG agreed well between DISA and PET. However, regional percentage uptake of 99mTc-tetrofosmin was generally higher on the uncorrected 99mTc-tetrofosmin images than on the single 99mTc-tetrofosmin images, especially in areas of low flow (percentage count of 99mTc-tetrofosmin > or = 50%). The crosstalk correction contributed to improving the agreement between regional percentage uptakes and significantly improved the detectability of myocardial perfusion-metabolism mismatching.

CONCLUSION

With 3-channel acquisition and weighted-scatter correction of crosstalk from the 18F photopeak to the 99mTc photopeak, DISA with 99mTc-tetrofosmin and FDG is feasible for assessing regional myocardial perfusion and viability.

Preoperative demonstration of the Adamkiewicz artery by magnetic resonance angiography in patients with descending or thoracoabdominal aortic aneurysms

OBJECTIVE

Investigating the possibility of magnetic resonance angiography (MRA) to visualize the Adamkiewicz artery of as a preoperative study of thoracic aortic aneurysms.

METHODS

From February 1998 to March 1999, 26 consecutive patients who had aneurysms of the thoracoabdominal or descending aorta underwent preoperative MRA to visualize the Adamkiewicz artery. Mean age was 60.5+/-11.5 years. Fifteen patients had non-dissecting aneurysm and 11 had aortic dissections. Nineteen patients underwent replacement of the aneurysms, four patients underwent endovascular stent-graft repair, and three patients were discharged without treatment of aneurysm. MRA was performed on a 1.5-T system (Magnetom, Siemens) and data acquisition was repeated two times following injection of gadolinium-DTPA. Source images were reconstructed with multiplanar reconstruction and maximum intensity projection. Criteria for the Adamkiewicz artery of were that the artery ascends from the dorsal branch of the intercostal or lumbar artery to the anterior mid-sagital surface of the spinal cord in the early phase.

RESULTS

The Adamkiewicz arteries were demonstrated in 18 patients (69%). These arteries were originated from the left intercostal or lumbar arteries in 13 (72.2%) patients and from the right in 5 (27.8%) and from the Th8 branch in three, Th9 in seven, Th10 in two, Th11 in four, and L1 in two. All patients had graft replacement of the aorta using a partial bypass. All intercostal or lumber arteries, which were visualized as the origin of the Adamkiewicz artery, were reattached to the grafts. No spinal cord injury occurred.

CONCLUSION

Preoperative detection the Adamkiewicz artery was possible by MRA and was very useful to reduce the incidence of ischemic injury of the spinal cord during surgery of the thoracoabdominal or descending aorta.

Phylogeny of the lady fern group, tribe Physematieae (Dryopteridaceae), based on chloroplast rbcL gene sequences

Nucleotide sequences of the chloroplast gene rbcL from 42 species of the fern tribe Physematieae (Dryopteridaceae) were analyzed to gain insights into the inter- and intrageneric relationships and the generic circumscriptions in the tribe. The phylogenetic relationships were inferred using the neighbor-joining and maximum-parsimony methods, and both methods produced largely congruent trees. These trees reveal that: (1) Athyrium, Cornopteris, Pseudocystopteris, and Anisocampium form a clade and Athyrium is polyphyletic; (2) Deparia sensu lato is monophyletic and Dictyodroma formosana is included in the Deparia clade; (3) Diplaziopsis forms a clade with Homalosorus, which is isolated from the other genera of the Physematieae; (4) Monomelangium is included in the monophyletic Diplazium clade; and (5) Rhachidosorus is not closely related to either Athyrium or Diplazium.

Attenuation correction for cardiac dual-head gamma camera coincidence imaging using segmented myocardial perfusion SPECT

The diagnostic accuracy of cardiac FDG imaging obtained with the dual-head coincidence gamma camera (DHC) is impaired by artifacts induced by nonuniform attenuation. This study proposed a new method (registration and segmentation method for attenuation correction [AC-RS]) to correct these attenuations in the chest region without the need for additional hardware or expensive transmission scanning equipment.

METHODS

Before DHC imaging, 99mTc-tetrofosmin SPECT was performed using dual-energy acquisition from both the photopeak and Compton scatter windows. The scatter window images of the 99mTc-tetrofosmin were then registered 3-dimensionally with the cardiac DHC images and segmented into anatomic regions to obtain body and lung contours by applying the optimal threshold method on localized histograms. Theoretic attenuation coefficient values were assigned to the corresponding anatomic regions, and the DHC emission images were reconstructed using these attenuation correction factors. The results were quantitatively evaluated by imaging a cardiac phantom filled with a uniform solution and placed in a chest phantom. Eight nondiabetic subjects were also examined using this technique, and the results were compared with those of measured attenuation-corrected PET images.

RESULTS

Use of this technique in phantom and clinical studies decreased the degree of artifacts seen in the inferior wall activity and corrected the emission images. When the results were compared with those of PET scans, the regional relative counts of the uncorrected DHC scan did not correlate with the results of the PET scan. However, the regional relative counts of the AC-RS-corrected DHC scan exhibited a linear correlation with the results of the PET scan (r = 0.73; P < 0.001).

CONCLUSION

Reasonably accurate attenuation-corrected cardiac DHC images can be obtained using AC-RS without the need for transmission scanning.

Case report: stent placement in support of intravascular ultrasound in a woman with atypical lower abdominal aortic stenosis

Localized stenosis confined to the distal abdominal aorta near the bifurcation is an atypical manifestation of atherosclerosis, particularly in a woman. We report the case of a middle-aged woman who presented with a focal stenosis accompanied by heavy calcification in the distal abdominal aorta. The lesion was successfully treated by Palmaz stent placement under intravascular ultrasound guidance.

MRA of the Adamkiewicz artery: a preoperative study for thoracic aortic aneurysm

PURPOSE

The purpose of this work was to investigate the ability of MR angiography (MRA) to visualize the Adamkiewicz artery (AKA) as a preoperative study of thoracic aortic aneurysm to prevent ischemic injury of the spinal cord.

METHOD

Twenty-six patients scheduled for surgical or endovascular stent-graft repair of thoracic aortic aneurysm were studied with a three-dimensional contrast MRA. Data acquisition was repeated two times following injection of Gd-DTPA. Source images were processed with multiplanar reconstruction and maximum intensity projection.

RESULTS

The AKA was identified in 69% (18/26). In three patients, selective angiography of the intercostal artery confirmed the AKA at the same level and side predicted by MRA. The anterior spinal artery and the anterior medullary vein were observed in 50% (13/26) and 65% (17/26), respectively.

CONCLUSION

Contrast MRA is a promising technique to visualize the AKA noninvasively as a preoperative evaluation of thoracic aortic aneurysms.

Use of ECG-gated SPET to assess the evolution of perfusion after acute myocardial infarction

Serial improvement in myocardial perfusion images from the acute or subacute to the chronic stage of acute myocardial infarction (AMI) has been attributed to improved coronary microcirculation or cell function after acute ischaemia and reperfusion. However, conventionally used non-gated imaging cannot eliminate the effect of improved regional contraction. We studied the possibility that such scintigraphic improvement reflects the functional recovery by using ECG-gated myocardial perfusion imaging with technetium-99m sestamibi. Nineteen AMI patients who received acute reperfusion therapy underwent ECG-gated myocardial single-photon emission tomography (SPET) in the subacute and chronic stages. Serial changes in regional image count distributions were analysed on the non-gated, end-diastolic (ED) and end-systolic (ES) images by using segmental mean percent peak activity (MPA) and AMPA (MPA in chronic stage - MPA in subacute stage) on bull's-eye polar maps. These changes were compared with those in regional wall motion on biplane left ventriculography (LVG) from the acute (just after reperfusion) to the chronic stage. During the follow-up, regional wall motion remained the same in 42 (group A) but improved in 17 (group B) of the 59 ischaemically compromised segments. MPA showed no improvement in group A but significant improvement in group B on the non-gated and ES images (P<0.0001 and P<0.001, respectively). However, MPA on the ED images showed no improvement in either group. In the follow-up study of AMI, the scintigraphic improvement documented on the non-gated myocardial images appears to be mainly related to the recovery of wall thickening and not to a real improvement in myocardial perfusion. Therefore, ECG-gated myocardial imaging, which enables simultaneous assessment of changes in perfusion and contraction, is preferable to conventional non-gated imaging for follow-up of AMI.

Brain fluorine-18 fluorodeoxyglucose imaging with dual-head coincidence gamma camera: comparison with dedicated ring-detector positron emission tomography

BACKGROUND AND PURPOSE

Dual-head coincidence gamma camera (DHC) imaging has been proposed as an alternative to dedicated ring-detector positron emission tomography (dr-PET) for clinical fluorodeoxyglucose (FDG) studies. The purpose of this investigation was to assess the quality of DHC images in FDG studies of the human brain.

METHODS

Seven healthy volunteers and 12 patients with various cerebral disorders underwent consecutive brain dr-PET and DHC with FDG. All sets of images were compared semiquantitatively using regions of interest.

RESULTS

Cortical count ratios to the cerebellum on DHC and dr-PET images did not differ significantly among the volunteers, except in the superior frontal cortex and thalamus. In all studies including those of cerebral disorders, the mean cortical-to-cerebellar ratios of DHC and dr-PET images correlated closely.

CONCLUSION

FDG imaging with DHC delineated the metabolic distribution of glucose in the brain as well as dr-PET did, except in the superior frontal cortex and thalamus. Therefore, DHC may be a dedicated cost-effective means of detecting metabolic abnormalities in the brain.

Histologic comparison of coronary and iliac atherectomy tissue from cases of in-stent restenosis

Pathologically, restenotic lesions after stenting were investigated by use of atherectomized tissues of seven coronary and seven iliac arteries. The mean interval of the stent deployment to restenosis was 9.1 months for the coronary artery and 33.7 months for the iliac artery, indicating a 3.7-fold longer interval for the latter. This study does not include cases of acute thrombotic occlusion. The atherectomized tissue from restenotic coronary arteries showed abundant neointima with alpha-actin-positive and ultrastructually synthetic-type smooth muscle cells in a rich myxomatous extracellular matrix. In the iliac arteries, the predominant component of restenosis consisted of organized thrombi. The neointima of the iliac arteries was mature, and only a small amount of spindle cells were observed in the hyalinized matrix. The tissue that developed restenosis after stenting was different in the coronary and iliac arteries included in this series. This study on the atherectomized tissue suggests that even in the chronic stage, a major cause of in-stent restenosis among the larger caliber vessels such as the iliac artery is not neointima but stent thrombosis.

Intravascular ultrasound observations during iliac stent deployment

BACKGROUND

To evaluate the role of intravascular ultrasound (IVUS) during iliac stent deployment, with comparison of four major types of iliac stents.

METHODS

Thirty-eight iliac arteries of 37 patients were observed with intravascular ultrasound after implantation of various stents including Palmaz stents in 10, Memotherm stents in 11, Wallstent in 10, and Strecker stents in 7. Quantitative measurements on ultrasound included the ratio of the short-axial to the long-axial diameters of the stent (symmetry index), the ratio of stent cross-sectional area to that of the reference lumen (expansion index), and stent-to-wall apposition.

RESULTS

Intravascular ultrasound revealed significant differences among four major types of iliac stent, in spite of satisfactory angiographic appearances in all patients. It demonstrated significant deformity of the Strecker stent (symmetry index of 0.76-0.09) compared with other stents. The Memotherm stent and the Palmaz stent were superior to other stents in terms of degree of expansion (mean expansion index of 0.87 and 0.82 respectively). Stent cross-sectional area greater than 80% of the reference lumen could be sufficient for iliac stent deployment. The Palmaz stent was superior to other stents in terms of stent-to-wall apposition.

CONCLUSIONS

Intravascular ultrasound can provide precise and useful cross-sectional morphological and quantitative information in terms of stent configuration, degree of stent expansion, and stent-to-wall apposition.

Three-dimensional CT imaging of aneurysm of aberrant right subclavian artery

We report a case of an aneurysm originating from an aberrant right subclavian artery, which was incidentally found as a compression deformity of the upper esophagus on a barium study in a 46-year-old man. Computed tomography (CT) clearly demonstrated the aneurysm of the aberrant right subclavian artery. In particular, reconstructed three-dimensional CT (3D-CT) was valuable in evaluating the positional relationships between the anomalous vessel with aneurysm and other structures.

Autonomic function in hypertensive patients with neurovascular compression of the ventrolateral medulla oblongata

OBJECTIVE

To study whether abnormalities of autonomic function exist in patients with essential hypertension and neurovascular compression (NVC) of the medulla oblongata.

SUBJECTS AND METHODS

We studied 25 untreated patients with essential hypertension (13 men and 12 women, 27-74 years old). High-resolution magnetic resonance imaging and magnetic resonance angiography were used to detect NVC. Twenty-four-hour ambulatory monitoring of blood pressure and electrocardiogram were performed, and the power spectrum of heart rate variability was analyzed. On a separate day, various autonomic activity tests, including mental stress, hand grip, cold pressor, and Valsalva maneuver were performed. Baroreflex sensitivity was calculated from changes of blood pressure and R-R interval during phenylephrine infusion. A clonidine suppression test was also performed, with measurement of plasma catecholamine levels.

RESULTS

Fourteen of 25 patients (56%) had NVC (C group), and 11 patients did not have NVC (NC group). There were no significant differences in age, sex, family history, or duration of hypertension between the C and NC groups. Average 24-h systolic blood pressure was similar between the two groups, although 24-h diastolic blood pressure was higher in the C group than the NC group. Daytime, night-time, and 24-h heart rate was significantly higher in the C group than in the NC group. Night-time low frequency/high frequency ratio was slightly higher in the C group. Plasma norepinephrine levels were significantly higher (467 +/- 217 versus 299 +/- 122 pg/ml), and baroflex sensitivity was slightly lower in the C group than in the NC group. Responses of blood pressure and heart rate to mental stress, cold pressor, hand grip, Valsalva maneuver, phenylephrine infusion, and clonidine tests were not significantly different between the two groups.

CONCLUSIONS

NVC of the medulla oblongata was frequently found in patients with essential hypertension. Patients with NVC appeared to have enhanced sympathetic nervous activity compared with those without the compression.

[MR angiography of steno-occlusive lesions of intracranial arteries: a comparative study between turbo MRA and conventional MRA]

PURPOSE

To compare the quality and diagnostic accuracy of images of intracranial steno-occlusive lesions obtained by conventional MRA and turbo MRA reconstructed using the zero-filled interpolation technique in the slice-select direction.

MATERIALS AND METHODS

Eighteen patients with suspected steno-occlusive lesions of the intracranial arteries were studied with two types of three-dimensional time-of-flight angiography and conventional digital subtraction angiography. In total, 45 steno-occlusive lesions were quantitatively measured using calipers and correlated with DSA stenosis. A phantom that simulated vessels with stenosis was also imaged using the two types of MRA under the same conditions as those employed in the clinical study.

RESULTS

Compared with conventional MRA, turbo MRA reduced the jaggedness of vessels and offered appearances more similar to those of DSA in the antero-posterior and lateral views. The severity of stenosis was classified into five grades based on the percentage of occlusion: not significant (0-24%), mild (25-49%), moderate (50-74%), severe (75-99%), and occlusive (100%). Neither turbo MRA nor conventional MRA showed any discrepancy from DSA above grade-1 stenosis.

CONCLUSION

The advantage of turbo MRA is its ability to reduce the jaggedness of vessels on conventional MRA, and to simplify the recognition of vessel contours without prolonging acquisition time. Turbo MRA and conventional MRA have equally high diagnostic accuracy for steno-occlusive lesions.

Late in-stent restenosis of the abdominal aorta in a patient with Takayasu's arteritis and related pathology

This report describes an in-stent restenosis of the infrarenal aorta in a patient with Takayasu's arteritis in a nonactive state. A 10-mm-diameter Wallstent had been deployed 42 months previously. The stented restenosed segment was replaced by a surgical graft. Histopathological examination of the excised aortic segment showed a thin layer of fibrocellular neointima and massive organized and calcified thrombus. To our knowledge, this is the first histopathological report of a late in-stent restenosis of the abdominal aorta in Takayasu's arteritis.

Differences between recombinant PTTH and crude brain extracts in cAMP-mediated ecdysteroid secretion from the prothoracic glands of the silkworm, Bombyx mori

The ability of recombinant prothoracicotropic hormone (rPTTH) or crude brain extract (cBRAIN) of Bombyx mori to stimulate ecdysteroid secretion from prothoracic glands (PGs) was investigated throughout the fifth instar and the first day of the pupal stage. Crude brain extracts could stimulate much higher ecdysteroid secretion than rPTTH during a 2h incubation. Recombinant PTTH did not increase the level of glandular cyclic AMP, except on days 4 and 5 of the fifth instar. Glandular cAMP levels were increased by cBRAIN from day 0 until day 5 of the fifth instar with the highest increase on day 3. On this day, rPTTH could not stimulate any increase of ecdysteroid secretion from the PGs during a 30min incubation. On the contrary, PGs incubated with cBRAIN for 30min showed increased secretory activity. Furthermore, on day 3 and in the absence of extracellular Ca(2+), rPTTH did not increase the glandular cAMP levels but cBRAIN did. Recombinant PTTH-stimulated ecdysteroid secretion from day 3 PGs was dependent on extracellular Ca(2+) in a dose-dependent manner. However, cBRAIN could stimulate ecdysteroid secretion even in the absence of extracellular Ca(2+). Taken together, the results of these experiments suggest the presence of a previously unknown cerebral prothoracicotropic factor that can stimulate glandular cAMP levels and ecdysteroid secretion from the PGs of Bombyx mori.

Complete genome sequence of an aerobic hyper-thermophilic crenarchaeon, Aeropyrum pernix K1

The complete sequence of the genome of an aerobic hyper-thermophilic crenarchaeon, Aeropyrum pernix K1, which optimally grows at 95 degrees C, has been determined by the whole genome shotgun method with some modifications. The entire length of the genome was 1,669,695 bp. The authenticity of the entire sequence was supported by restriction analysis of long PCR products, which were directly amplified from the genomic DNA. As the potential protein-coding regions, a total of 2,694 open reading frames (ORFs) were assigned. By similarity search against public databases, 633 (23.5%) of the ORFs were related to genes with putative function and 523 (19.4%) to the sequences registered but with unknown function. All the genes in the TCA cycle except for that of alpha-ketoglutarate dehydrogenase were included, and instead of the alpha-ketoglutarate dehydrogenase gene, the genes coding for the two subunits of 2-oxoacid:ferredoxin oxidoreductase were identified. The remaining 1,538 ORFs (57.1%) did not show any significant similarity to the sequences in the databases. Sequence comparison among the assigned ORFs suggested that a considerable member of ORFs were generated by sequence duplication. The RNA genes identified were a single 16S-23S rRNA operon, two 5S rRNA genes and 47 tRNA genes including 14 genes with intron structures. All the assigned ORFs and RNA coding regions occupied 89.12% of the whole genome. The data presented in this paper are available on the internet homepage (http://www.mild.nite.go.jp).

Saline-jet aspiration thrombectomy catheter. Clinical results in patients with venous thrombosis

PURPOSE

To evaluate hydraulic thrombectomy using a saline-jet aspiration thrombectomy catheter in the treatment of venous thrombosis.

MATERIAL AND METHODS

Ten patients underwent 12 hydraulic thrombectomy procedures using 2.7 or 4.0 mm catheters. The site of the thrombus was either central, peripheral or in portal veins. The age of the thrombi was between 2 and 60 days (mean 19.7 days). The efficacy of hydraulic thrombectomy was evaluated based on the aspirated thrombus ratio (ATR), i.e. the volume of the thrombus aspirated divided by the volume of the thrombus before thrombectomy. ATR was estimated by comparing the angiograms of the lesion before and after thrombectomy.

RESULTS

Soft thrombi were usually rapidly removed. ATR was >2/3 in 3, 2/3-1/3 in 2, 1/3-0 in 4, and 0 in 1 patient. The activation time of the injector was 23-224 s (mean 102 s) and the volume of aspirated blood was 30-680 ml (mean 250 ml). Compensatory infusion of saline was performed for blood loss, and 400 ml of packed red blood cells was transfused in 1 patient. No complications of the hydraulic thrombectomy were observed. Thrombolysis or additional treatment were performed in 9 patients.

CONCLUSION

Hydraulic thrombectomy using this catheter can contribute to the treatment of venous thrombosis.

Three-dimensional thoracic modeling for an anatomical compatibility study of the implantable total artificial heart

Anatomical compatibility with the thoracic cavity is important in developing a completely implantable total artificial heart (TAH). The purpose of this study was to examine the optimal morphology of our TAH and to develop a computer implantation simulation environment for preoperational discussion. As the first stage, we constructed a prototype simulation system by creating a 3-D surface model of a thoracic cavity and one of a TAH. In this system, the thoracic surface model, composed of the aorta, pulmonary artery, ventricle resected heart, diaphragm, and thoracic wall, was created based on the organ contours extracted from electrocardiogram (ECG)-synchronized ultrafast computer tomographic images. The accuracy of the thoracic model was discussed using a phantom. The fitting study can be performed on the computer with the model of the thorax and that of the TAH. In the future, construction of a database for the thoracic cavities of heart failure patients is planned to improve the morphology of the TAH.

Myocardial imaging with 123I-BMIPP in patients with congestive heart failure

First, we studied the diagnostic utility of myocardial imaging with 123I-BMIPP (BMIPP), a 3-methyl-branched fatty acid analog, in patients with various types of cardiomyopathy and left ventricular dysfunction (ejection fraction below 40%) by comparing with myocardial flow tracer imaging. The incidence of a dissociation between myocardial BMIPP and 201Tl distributions (BMIPP < 201Tl) as a marker of metabolic abnormality in viable tissue varied considerably among various heart diseases. Patients with ischemic cardiomyopathy and the dilated form of hypertrophic cardiomyopathy had a higher incidence while those with idiopathic dilated, alcoholic and hypertensive cardiomyopathy had a lower incidence. These results suggest that the marked difference between ischemic and idiopathic dilated cardiomyopathies may contribute to the differential diagnosis between these two diseases which are main basic abnormalities in congestive heart failure. Second, we investigated the relationship between myocardial BMIPP uptake and ventricular stress in patients with right ventricular pressure overload due to pulmonary hypertension. Myocardial BMIPP uptake in the right ventricle estimated by referring to uptake in the left ventricle showed a significant correlation with mean pulmonary artery pressure (mPAP) and no significant difference with myocardial 99mTc-sestamibi uptake in the 15-81 mmHg mPAP range. These results suggest that myocardial utilization of free fatty acid may be preserved in the presence of higher ventricular wall stress.

Sustained elevation of plasma brain natriuretic peptide levels associated with progressive ventricular remodelling after acute myocardial infarction

Previous studies have shown that levels of plasma brain natriuretic peptide (BNP) increase in an early phase of acute myocardial infarction. However, the relations between plasma BNP levels and left ventricular remodelling, which occurs long after acute myocardial infarction, are not fully understood. Venous plasma BNP levels were measured 2, 7, 14, 30, 90 and 180 days after the onset of acute myocardial infarction in 21 patients. Left ventricular end-diastolic volume index (EDVI, ml/m2) in acute (5 days) and chronic (6 months) phases were assessed by electron-beam computed tomography using Simpson's method. The remodelling group (n=9) was defined by an increase in EDVI >/=5 ml/m2 relative to the baseline value. Plasma BNP levels on days 2, 7, 14, 30 and 90 were significantly higher in the remodelling group than in the non-remodelling group (n=12, P<0.05). Sustained elevation of plasma BNP levels was noted from day 2 (61+/-12 pmol/l) to day 90 (55+/-12 pmol/l) and significantly decreased on day 180 (24+/-3 pmol/l) in the remodelling group. In contrast, plasma BNP levels significantly decreased from day 2 (25+/-4 pmol/l) to day 90 (9+/-1 pmol/l) and reached a steady level thereafter in the non-remodelling group. Plasma BNP levels on day 7 correlated positively with an increase in EDVI (r=0.70, P<0.001) from the acute to chronic phase. More importantly, the sustained elevation of plasma BNP (percentage decrease smaller than 25%) from day 30 to day 90 identified patients in the remodelling group with a sensitivity of 100% and a specificity of 83%. In conclusion, not only the high levels of plasma BNP in an acute phase, but also the sustained elevation of plasma BNP in a chronic phase, may be associated with progressive ventricular remodelling occurring long after acute myocardial infarction.

[Assessment of left ventricular function by 201Tl ECG-gated myocardial SPECT]

We applied the QGS program for LV function analysis (described by Germano, 1995) to a 201Tl SPECT study at rest, and estimated its accuracy. We performed 201Tl ECG-gated myocardial SPECT in 25 patients with ischemic heart disease under an acquisition time used in the routine 99mTc ECG-gated SPECT study. The quality of the gated images was visually assessed with a 4-point grading system. LVEDV, LVESV, LVEF determined by the QGS program were compared with those by Simpson's method on biplane LVG in 25 patients. Regional wall motion scores in 7 myocardial segments were assessed on the three-dimensional display created by the QGS program and the cine display of biplane LVG with a 5-point grading system. Wall motion scores obtained by the QGS program were compared with those by LVG. Although 72.0% of 201Tl ECG-gated SPECT images were fair or poor in image quality, there were good correlations between the values obtained by the QGS program and LVG (LVEDV: r = 0.82, LVESV: r = 0.88, LVEF: r = 0.89). In addition, wall motion scores by the QGS program were correspondent to those by LVG in 77.1% of all 175 myocardial segments. We conclude that the QGS program provides high accuracy in evaluating left ventricular function even from 201Tl ECG-gated myocardial SPECT data.

Diagnostic value of plasma levels of brain natriuretic peptide in arrhythmogenic right ventricular dysplasia

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by local or diffuse wall motion abnormalities in the right ventricle (RV), associated with recurrent ventricular tachycardia (VT) of RV origin. Brain natriuretic peptide (BNP) was first isolated from a porcine brain extract. In humans, BNP is expressed predominantly in the ventricles of failing hearts, and its expression has been observed primarily in myocytes in the interstitial fibrous area in dilated cardiomyopathy. We hypothesized that BNP is increasingly secreted from the residual myocytes within the atrophic tissue in patients with ARVD.

METHODS AND RESULTS

Plasma BNP levels were measured in 17 patients with ARVD, 12 patients with idiopathic RV outflow tract tachycardia (RVOT), and 120 control subjects. We performed cardiac catheterization, RV endomyocardial biopsy, electron- beam CT, and biventricular endomyocardial mapping in the ARVD patients. There was a significant increase in plasma BNP levels in the ARVD patients compared with the RVOT patients and control subjects (61.4+/-59.6 pg/mL versus 8.3+/-5. 5 pg/mL and 9.3+/-5.8 pg/mL; P<0.0001, respectively). The plasma BNP levels had no correlation with any of the hemodynamic data, but they had a significant correlation with the RV ejection fraction (r=-0. 588, P=0.025) and with the fractionated-area scores (r=0.705, P=0. 005). Light microscopic immunohistochemistry showed strong BNP immunoreactivity in residual myocytes with fibrofatty replacement.

CONCLUSIONS

These results suggest that plasma BNP levels were not increased in RVOT patients but were increased in ARVD patients, and that the increased BNP levels indicate the severity of both the RV dysfunction and the arrhythmogenic substrate.

Fluorine-18-fluorodeoxyglucose PET identification of cardiac metastasis arising from uterine cervical carcinoma

Cardiac metastasis of uterine cervical carcinoma is rare. We describe a patient with a past history of uterine cervical carcinoma who presented with metastasis to the heart, lungs and distant lymph nodes 3 yr after surgery and chemotherapy. Since the patient complained of chest pain and demonstrated electrocardiogram abnormalities, we performed echocardiography, electron beam CT and MRI, which revealed a tumor in the right ventricular wall. The tumor was assessed by 67Ga scintigraphy and 18F-fluorodeoxyglucose (FDG) PET scanning. The mean differential 18F-FDG uptake ratio of the tumor was 7.9, suggesting malignancy, which was later confirmed by myocardial biopsy. Information about the extent of the tumor and partial necrosis within it was provided by 18F-FDG PET. Although both radionuclide imaging techniques also detected metastatic lesions in the lungs and lymph nodes, 18F-FDG PET scanning detected small lesions more sensitively than 67Ga scintigraphy.

Sympathetic reinnervation demonstrated on serial iodine-123-metaiodobenzylguanidine SPECT images after cardiac transplantation

The transplanted heart is without autonomic nervous control in the early postsurgical period. We present here a case of cardiac transplantation in which 123I-metaiodobenzylguanidine (MIBG) SPECT and an exercise-loading test were used to monitor the sympathetic reinnervation. The distribution of myocardial 123I-MIBG uptake extended with time from 1 to 2 yr after surgery. However, functional improvement, estimated by the heart rate response to exercise, was not discernable during this period. The findings in this case suggest the feasibility of 123I-MIBG SPECT imaging in the serial monitoring of sympathetic reinnervation after transplantation and that scintigraphic evidence of reinnervation precedes functional recovery.

Impaired regional fatty acid uptake and systolic dysfunction in hypertrophied right ventricle

Little information is available regarding the determinants of systolic contractile function of the hypertrophied right ventricle (RV). The purpose of this study was to clarify the relationship between myocardial metabolism and contractile function in the hypertrophied RV due to pulmonary hypertension (PH).

METHODS

Iodine-123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and 99mTc-sestamibi (MIBI) SPECT were performed to calculate the RV-to-left ventricle (LV) tracer uptake ratio (RV/LV) in 21 patients with PH (6 with primary PH and 15 with chronic thromboembolic PH). The patients also underwent electron-beam CT to assess RV ejection function (RVEF) and percentage systolic wall thickening (%SWT) and right heart catheterization to measure mean pulmonary arterial pressure (mPAP).

RESULTS

There were significant positive correlations between mPAP and MIBI-RV/LV (r = 0.89, p < 0.001) and between mPAP and BMIPP-RV/LV (r = 0.86, p < 0.001). However, 8 patients showed lower BMIPP-RV/LV than MIBI-RV/LV, indicating the impairment of myocardial fatty acid uptake in the RV. These patients had lower RVEF and %SWT compared to those with normal myocardial fatty acid uptake (RVEF = 28% +/- 10% compared to 40% +/- 9% and %SWT = 33% +/- 27% compared to 74% +/- 30%, respectively; p < 0.05 for both comparisons). Although mPAP did not differ between the groups, the RVEF-mPAP and %SWT-mPAP regression lines drawn from the patients with impaired myocardial fatty acid uptake were located below the lines from the patients with normal myocardial fatty acid uptake, suggesting disproportionately decreased RV myocardial contractility for a given mPAP in patients with impaired myocardial fatty acid uptake. The patients with the impaired fatty acid uptake in the RV had a significantly higher death rate (log-rank test, p < 0.05).

CONCLUSION

The results from this preliminary study suggest that myocardial fatty acid uptake is impaired in the failing hypertrophied RV due to PH.

Aspirin renography in diagnosis of unilateral renovascular hypertension

We previously proposed that aspirin can enhance the diagnostic sensitivity of renography with [123I] orthoiodohippurate (OIH) in patients with suspected unilateral renovascular hypertension (RVH). In this study we assessed the sensitivity and specificity of this method. Twenty-four patients, 14 with unilateral RVH and 10 with essential hypertension, were studied. For all patients with RVH, definitive diagnosis was based on the results of angiography and the response to renal arterial angioplasty after this study. For all patients with essential hypertension, we confirmed that there was little if any stenosis of the renal artery by digital subtraction angiography or Doppler sonography. Renography with [123I]OIH or 99mTc-mercaptoacetyltriglycine (MAG3) was done once before and once after the oral administration of aspirin (20 mg/kg). We considered renal blood flow to be decreased if the time to the peak in renography was 5 min or more, and defined the peak times of the kidneys as different if separated by 2 min or more. Unilateral RVH was diagnosed when both criteria were met. Renography before aspirin administration indicated RVH in 7 of the 14 patients with RVH, and renography after aspirin indicated RVH in 13 of the 14 patients. Of the 10 patients with essential hypertension, renography before and after aspirin administration showed no difference between the kidneys in 8 patients. Thus, aspirin renography increased the sensitivity from 50% to 93%, but did not change the specificity (80%) in the diagnosis of RVH. These results suggest that renography with [123I]OIH or 99mTc-MAG3 for the diagnosis of unilateral RVH is more sensitive when aspirin is used.