Heterogeneity of perivascular astrocyte endfeet depending on vascular regions in the mouse brain

Astrocytes interact with not only synapses but also brain blood vessels through perivascular astrocyte endfeet (PV-AEF) to form the neurovascular unit (NVU). However, PV-AEF components have not been fully identified. Here, we biochemically isolated blood vessels from mouse brain homogenates and purified PV-AEF. The purified PV-AEF were observed in different sizes, similar to PV-AEF on brain blood vessels. Mass spectrometry analysis identified 9,762 proteins in the purified PV-AEF, including cell adhesion molecules, nectin-2δ, Kirrel2, and podoplanin. Immunofluorescence microscopic analysis revealed that nectin-2δ and podoplanin were concentrated mainly in arteries/arterioles and veins/venules of the mouse brain, whereas Kirrel2 was mainly in arteries/arterioles. Nectin-2α/δ, Kirrel2, and podoplanin were preferentially observed in large sizes of the purified PV-AEF. Furthermore, Kirrel2 potentially has cell adhesion activity of cultured astrocytes. Collectively, these results indicate that PV-AEF have heterogeneity in sizes and molecular components, implying different roles of PV-AEF in NVU function depending on vascular regions.

Necl2/3-mediated mechanism for tripartite synapse formation

Ramified, polarized protoplasmic astrocytes interact with synapses via perisynaptic astrocyte processes (PAPs) to form tripartite synapses. These astrocyte-synapse interactions mutually regulate their structures and functions. However, molecular mechanisms for tripartite synapse formation remain elusive. We developed an in vitro co-culture system for mouse astrocytes and neurons that induced astrocyte ramifications and PAP formation. Co-cultured neurons were required for astrocyte ramifications in a neuronal activity-dependent manner, and synaptically-released glutamate and activation of astrocytic mGluR5 metabotropic glutamate receptor were likely involved in astrocyte ramifications. Astrocytic Necl2 trans-interacted with axonal Necl3, inducing astrocyte-synapse interactions and astrocyte functional polarization by recruiting EAAT1/2 glutamate transporters and Kir4.1 K+ channel to the PAPs, without affecting astrocyte ramifications. This Necl2/3 trans-interaction increased functional synapse number. Thus, astrocytic Necl2, synaptically-released glutamate and axonal Necl3 cooperatively formed tripartite glutamatergic synapses in vitro. Studies on hippocampal mossy fiber synapses in Necl3 knockout and Necl2/3 double knockout mice confirmed these previously unreported mechanisms for astrocyte-synapse interactions and astrocyte functional polarization in vivo.

Localization of nectin-2δ at perivascular astrocytic endfoot processes and degeneration of astrocytes and neurons in nectin-2 knockout mouse brain

Nectins are Ca²⁺-independent immunoglobulin-like cell-cell adhesion molecules. In the nervous system, among four members (nectin-1, -2, -3, and -4), nectin-1 and -3 are asymmetrically localized at puncta adherentia junctions formed between the mossy fiber terminals and the dendrites of CA3 pyramidal neurons in the mouse hippocampus and heterophilic trans-interactions between nectin-1 and nectin-3 are involved in the selective interaction of axons and dendrites of cultured neurons. By contrast, nectin-2, which has two splicing variants, nectin-2α and -2δ, has not been well characterized in the brain. We showed here that nectin-2α was expressed in both cultured mouse neurons and astrocytes whereas nectin-2δ was selectively expressed in the astrocytes. Nectin-2δ was localized at the adhesion sites between adjacent cultured astrocytes, but in the brain it was localized on the plasma membranes of astrocytic perivascular endfoot processes facing the basement membrane of blood vessels. Genetic ablation of nectin-2 caused degeneration of astrocytic perivascular endfoot processes and neurons in the cerebral cortex. These results uncovered for the first time the localization and critical functions of nectin-2 in the brain.

Suppressive effects of dRYamides on feeding behavior of the blowfly, Phormia regina

Recently, dRYamides-1 and -2 have been identified as ligands of the neuropeptide Y-like receptor CG5811 in Drosophila melanogaster. It has also been reported in brief that injection of dRYamide-1suppresses the early feeding behavior called proboscis extension reflex (PER) in the blowfly Phormia regina. Immunohistochemical analyses by our group using anti-dRYamide-1 antiserum indicated symmetrical localization of 32 immunoreactive cells in the brain of P. regina. In order to analyze the mechanism of feeding regulation, we further investigated the effects of dRYamide-1 and -2 on intake volume, PER exhibition, and activity of the sugar receptor neuron. After injection of dRYamide-1 or -2, flies showed little change in the intake volume of sucrose solution, but a significant depression of PER to sucrose. Injection of dRYamide-1 revealed a significant decrease in the responsiveness of the sugar receptor neuron, although the injection of dRYamide-2 did not. These results suggest that the dRYamide peptides decrease feeding motivation in flies, as evaluated by PER threshold, through a mechanism that partially involves desensitization of the sugar receptor neuron.

Isolation of the bioactive peptides CCHamide-1 and CCHamide-2 from Drosophila and their putative role in appetite regulation as ligands for G protein-coupled receptors

There are many orphan G protein-coupled receptors (GPCRs) for which ligands have not yet been identified. One such GPCR is the bombesin receptor subtype 3 (BRS-3). BRS-3 plays a role in the onset of diabetes and obesity. GPCRs in invertebrates are similar to those in vertebrates. Two Drosophila GPCRs (CG30106 and CG14593) belong to the BRS-3 phylogenetic subgroup. Here, we succeeded to biochemically purify the endogenous ligands of Drosophila CG30106 and CG14593 from whole Drosophila homogenates using functional assays with the reverse pharmacological technique, and identified their primary amino acid sequences. The purified ligands had been termed CCHamide-1 and CCHamide-2, although structurally identical to the peptides recently predicted from the genomic sequence searching. In addition, our biochemical characterization demonstrated two N-terminal extended forms of CCHamide-2. When administered to blowflies, CCHamide-2 increased their feeding motivation. Our results demonstrated these peptides actually present as the major components to activate these receptors in living Drosophila. Studies on the effects of CCHamides will facilitate the search for BRS-3 ligands.

Change of autonomic nervous activity during pregnancy and its modulation of labor assessed by spectral heart rate variability analysis

PURPOSE OF INVESTIGATION

To elucidate the sequential changes of autonomic nervous activity during pregnancy, we examined heart rate variability on two positions and whether autonomic nervous activity affected duration of labor.

METHODS

Thirty-eight normal pregnant women were studied. Frequency domain parameters (HF, LF, LF/HF ratio) and heart rate were obtained by spectral HRV analysis in the supine and left recumbent position in three trimesters.

RESULTS

We found HF was significantly higher in early pregnancy, while the LF/HF ratio was significantly higher in late pregnancy. The LF/HF ratio was significantly lower when the left recumbent position was assumed. The LF/HF ratio was significantly higher in the longer labor group of primiparous women.

CONCLUSION

Our findings demonstrate that sympathovagal balance shifted progressively from a higher vagal modulation towards a higher sympathetic modulation, and the recumbent position activated vagal activity. It is suggested that increased sympathetic activity in late pregnancy could affect the duration of labor.

Positive affect among nursing home residents with Alzheimer's dementia: the effect of recreational activity

The experience of positive emotions is an integral component of quality of life. Research suggests that cognitive deficits in persons with dementia may impede their ability to generate pleasurable moments and hence decrease their positive affect. Therefore, structured recreation activities may have the potential to significantly improve resident affect. However, differences in affect between ordinary time and recreation time are not well known. The present study used previously published structured-observation instruments to measure affect and behaviour among 35 dementia residents at two nursing homes in Japan during ordinary time and during recreation time. A total of 3,854 one-minute observations were coded. Dementia residents expressed happiness over seven times more often during recreation time than during ordinary time. Over 60% of ordinary time was solitary, with 65.72% of all observed affect being 'Null Affect'. A total of 43.75% of residents expressed happiness only during recreation time. In addition 48.9% of all behaviour during 'Ordinary Time' was coded as 'Null Behaviour', which indicated that the resident was sitting and doing nothing. Findings indicate that recreation time is significantly higher in positive affect than ordinary time and that virtually all residents benefited from recreation.

Comparison of left atrial size by freehand scanning three-dimensional echocardiography and two-dimensional echocardiography

AIMS

As the left ventricular (LV) dimension is a poor indicator of LV volume, there are well-known limitations of left atrial (LA) antero-posterior dimensions as indicators of chamber size. LA volume has been shown to provide a more accurate assessment of LA size than LA dimension. To evaluate two-dimensional (2D)-derived LA volume in assessing LA size, we compared LA dimension and 2D LA volume with three-dimensional (3D)-derived LA volume.

METHODS

We performed transthoracic freehand scanning 3D echocardiography (3D EchoTech, Germany) using magnetic fields and a harmonic imaging system in 32 patients. We collected a series of LA tomograms by slowly tilting the probe (fan-like scanning) in the parasternal position. The 3D LA volume was calculated by using the multiplanar Simpson's method. The 2D LA volume was measured by using the modified biplane Simpson's rule.

RESULTS

LA antero-posterior dimensions and 2D volumes showed a significant positive correlation with 3D LA volumes. However, the correlation coefficient was significantly greater for the relationship between 2D LA volumes and 3D LA volumes than for that between LA dimensions and 3D LA volume.

CONCLUSIONS

The 2D LA volumes provide a more accurate measure of the true size of the LA and are more sensitive to changes in LA size.

Increased expression of cyclooxygenase-2 protein in 4-nitroquinoline-1-oxide-induced rat tongue carcinomas and chemopreventive efficacy of a specific inhibitor, nimesulide

Expression of cyclooxygenase (COX)-2 protein in 4-nitroquinoline-1-oxide (4-NQO)-induced rat tongue lesions and the postinitiation chemopreventive potential of a selective COX-2 inhibitor, nimesulide (NIM), were examined in Fischer 344 male rats. NIM was administered in the diet at doses of 150, 300, and 600 ppm for 14 weeks after treatment with 25-35 ppm 4-NQO in the drinking water for 12 weeks. Western blot analysis revealed COX-2 protein to be barely expressed in the normal tongue epithelia, whereas it was increased approximately 6-fold in squamous cell carcinomas (SCCs). Immunohistochemically, COX-2 protein was diffusely present in SCCs and dysplasia but expressed only in basal cells in hyperplasia and papillomas. In basal cells of normal epithelia, it was also occasionally weakly stained. NIM dose-dependently decreased at doses of 150 and 300 ppm, the incidences of SCCs to 4 of 12 (33.3%) and 1 of 13 (7.7%) and their multiplicity to 0.33+/-0.49 and 0.08+/-0.28 per rat, respectively, as compared with 4-NQO alone group values of 9 of 11 (81.8%) and 1.00+/-0.77. A lesser decrease was observed with 600 ppm, the values being 5 of 12 (41.7%) and 0.50+/-0.67. NIM did not significantly affect the development of hyperplasias, dysplasias, and papillomas. These results clearly indicate chemopreventive potential of a selective COX-2 inhibitor against the postinitiation development of SCCs in rat tongue carcinogenesis.

Pathogenic Interactions Between Xanthomonas axonopodis pv. citri and Cultivars of Pummelo (Citrus grandis)

ABSTRACT The aggressiveness of strains of Xanthomonas axonopodis pv. citri on seven Citrus species, including Citrus sinensis (navel orange), C. paradisi (grapefruit), C. unshiu (Satsuma mandarin), C. junos (Yuzu), C. aurantifolia ('Mexican' lime), C. tachibana (Tachibana), and C. grandis (pummelo: 'Otachibana', 'Banpeiyu', and 'Anseikan'), were assessed by comparing lesion expansion and growth in planta, using a prick inoculation method. The existence of two groups distinct in aggressiveness was demonstrated on the pummelo cultivars, whereas the remaining species tested were uniformly susceptible. The two groups of strains were distinct in lesion expansion and growth in planta; however, both caused canker lesions on the 'Otachibana' pummelo. The sensitivity of the bacterial strains to phages Cp1 and Cp2 was associated with differences in aggressiveness. Namely, all the strains sensitive to Cp2 but resistant to Cp1 were aggressive to 'Otachibana', whereas all the strains sensitive to Cp1 but resistant to Cp2 were weakly aggressive. When a repetitive sequence-based polymerase chain reaction amplification was carried out by enterobacterial repetitive intergeneric consensus (ERIC) sequences (ERIC1R and ERIC2) as the primers, these two groups were also distinguishable by the presence or absence of a 1.8-kb DNA fragment among otherwise identical fragments. The 1.8-kb fragment was amplified only from the strains aggressive to C. grandis.

Agitated behavior in elderly nursing home residents with dementia in Japan

This study is the first investigation of the frequency of agitated behaviors in elderly dementia patients in Japanese nursing homes using the Cohen-Mansfield Agitation Inventory (J. Cohen-Mansfield, 1991). Despite major differences between Japanese and American cultures, findings were highly consistent with those of previous U.S. studies. Physically aggressive behavior, although evidenced by only 10-20% of the sample, comprised the strongest factor. A separate factor for verbal agitation also emerged. The behaviors declined during the evening and night shifts. In both the Japanese and U.S. samples, wandering, general restlessness, verbal agitation such as repetitious questioning, cursing, and complaining occurred most frequently. Another 4-point scale was used to code the degree to which agitated behavior occurred during eating, dressing, bathing, and toileting for each resident. The majority of aggressive behavior occurred in relation to personal caregiving, especially in regard to bathing. Despite major cultural differences, Japanese findings paralleled previous U.S. results.

Cardiac abnormalities in diabetic patients with mutation in the mitochondrial tRNA(Leu(UUR)) gene

An A-to-G transition at position 3243 of the mitochondrial DNA is known to be a pathogenic factor for mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), diabetes and cardiomyopathy. This mutation causes dysfunction of the central nervous system in MELAS. Because the heart, as well as the brain and nervous system, is highly dependent on the energy produced by mitochondrial oxidation, these tissues are more vulnerable to mitochondrial defects. Cardiac abnormalities were assessed in 10 diabetic patients associated with this mutation using echocardiography and 123I-metaiodobenzylguanidine (MIBG) scintigraphy, and compared with 19 diabetic patients without the mutation. Duration of diabetes, therapy, control of blood glucose and diabetic complications, such as diabetic retinopathy and nephropathy, were not different between the 2 groups. Diabetic patients with the mutation had a significantly thicker interventricular septum (16.8+/-3.7 vs 11.0+/-1.6mm, p<0.001) than those without the mutation. Fractional shortening was lower in diabetic patients with the mutation than those without it (30.7+/-7.0 vs 42.5+/-6.6, p<0.001). MIBG uptake on the delayed MIBG image was significantly lower in diabetic patients with the mutation than in those without the mutation (mean value of the heart to mediastinum ratio: 1.6+/-0.2 vs 2.0+/-0.4, p>0.05). In conclusion, left ventricular hypertrophy with or without abnormal wall motion and severely reduced MIBG uptake may be characteristic in diabetic patients with a mutation in the mitochondrial tRNA(Leu(UUR)) gene.

Insertional mutagenesis and cloning of the genes required for biosynthesis of the host-specific AK-toxin in the Japanese pear pathotype of Alternaria alternata

The Japanese pear pathotype of Alternaria alternata causes black spot of Japanese pear by producing a host-specific toxin known as AK-toxin. Restriction enzyme-mediated integration (REMI) mutagenesis was used to tag genes required for toxin biosynthesis. Protoplasts of a wild-type strain were treated with a linearized plasmid along with the restriction enzyme used to linearize the plasmid. Of 984 REMI transformants recovered, three produced no detectable AK-toxin and lost pathogenicity on pear leaves. Genomic DNA flanking the integrated plasmid was recovered from one of the mutants. With the recovered DNA used as a probe, a cosmid clone of the wild-type strain was isolated. Structural and functional analyses of an 8.0-kb region corresponding to the tagged site indicated the presence of two genes. One, designated AKT1, encodes a member of the class of carboxyl-activating enzymes. The other, AKT2, encodes a protein of unknown function. The essential roles of these two genes in both AK-toxin production and pathogenicity were confirmed by transformation-mediated gene disruption experiments. DNA gel blot analysis detected AKT1 and AKT2 homologues not only in the Japanese pear pathotype strains but also in strains from the tangerine and strawberry pathotypes. The host-specific toxins of these two pathotypes are similar in structure to AK-toxin. Homologues were not detected in other pathotypes or in non-pathogenic strains of A. alternata, suggesting acquisition of AKT1 and AKT2 by horizontal transfer.

Resting 123I-BMIPP scintigraphy in diagnosis of effort angina pectoris with reference to subsets of the disease

This study was undertaken to assess the diagnostic value of resting 123I-BMIPP scintigraphy in patients with effort angina pectoris. One hundred and four patients underwent scintigraphic and angiographic examinations. The subsets of the patients were stable effort angina pectoris (stable type) in 27 cases, new onset of effort angina pectoris (new onset type) in 21 cases, and worsening effort angina pectoris (worsening type) in 35 cases. The remaining 21 cases were subjects without evidences of coronary artery disease (non-CAD). 123I-BMIPP was injected under resting and pain free condition, then data for single photon emission tomography (SPECT) were acquired. The positive regional 123I-BMIPP defects in three coronary territories were visually judged on the tomographic images. The overall sensitivity to diagnose the patients was 62.6% (52/83) and the overall specificity to exclude non-CAD subjects was 95.2% (20/21). The detection rate in each subset of the disease was 48.1% (13/27) in stable type, 47.6% (10/21) in new onset type and 77.1% (27/35) in worsening type (p < 0.05 versus two other types). For detection of stenosed vessels, the overall sensitivity was 41.4% (56/148) and the overall specificity was 93.8% (152/164). The rate of detection of stenosed vessels was 31.7% (13/41) in stable type, 31.4% (11/35) in new onset type, and 55.6% (40/72) in worsening type (p < 0.05 versus two other types). Vessels with 75% stenosis were more sensitively detected in the worsening type (33.3%; 4/12) compared to the remaining two types (8.3%; 1/12) even though the difference was not significant. The resting 123I-BMIPP scintigraphy was therefore valuable in diagnosing patients with effort angina pectoris and involved coronary arteries especially in the subset of patients with worsening type.

Diabetes mellitus and cardiomyopathy--association with mutation in the mitochondrial tRNA(Leu)(UUR) gene

In this report, cardiac abnormalities in 2 diabetic patients with a mutation in the mitochondrial tRNA(Leu)(UUR)gene are described. The 2 patients exhibited left ventricular dilation and diffuse decreased wall motion. Cardiac catheterization studies revealed normal coronary angiography. In both patients, light microscopic examination of hematoxylin and eosin-stained sections revealed myocyte hypertrophy and perinuclear vacuolization and electron microscopy revealed an increase in the number and size of mitochondria and abnormal configuration of cristae. These findings suggest that mutations in mitochondrial DNA, such as an A-->G mutation at position 3243, should be considered as a cause not only of diabetes mellitus but also of cardiac involvement in patients with diabetes mellitus.

Application of the polymerase chain reaction for the diagnosis of malignant lymphoma of the nasal and oral cavities

Difficulties are often encountered in the diagnosis of malignant lymphoma of the oral and nasal cavities by histology and immunohistochemistry because these malignancies may be complicated by inflammation and necrosis. In the present study, immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements were examined by the polymerase chain reaction (PCR) in formalin-fixed and paraffin-embedded specimens obtained from 18 patients; the advantages of this method were evaluated. Twelve of these patients were diagnosed as having malignant lymphoma and six had tumors highly suggestive of malignant lymphoma. Fourteen (78%) of the 18 cases were diagnosed as malignant lymphoma histologically and immunohistochemically. Sixteen (89%) of the 18 cases were shown to be monoclonal by PCR. The four cases that could not be histologically or immunohistochemically diagnosed as malignant lymphoma showed monoclonal gene rearrangement by PCR. As a result, six patients suspected of having a malignant lymphoma were diagnosed as having one. The diagnosis of malignant lymphoma by PCR alone still has various problems. However, when the results of PCR are evaluated together with histopathological and immunohistochemical results, PCR makes a useful contribution to the diagnosis of malignant lymphomas of the nasal and oral cavities.

Primary pericardial mesothelioma demonstrated by magnetic resonance imaging

A 24-year-old man was hospitalized for an investigation of cardiac enlargement. Serum hyaluronic acid was increased to 238 ng/ml. Echocardiogram showed pericardial effusion with an area of increased density adjacent to the anterolateral wall of the left ventricle. A soft-tissue mass within the pericardial space was enhanced with gadolinium DTPA on magnetic resonance imaging. Open biopsy confirmed the presence of a malignant mesothelioma. Magnetic resonance imaging provided useful information regarding the tumor.

Apoptosis in the normal olfactory epithelium of the adult guinea pig

Among nerve cells of vertebrates, the olfactory epithelia are uncommon in their capacity for cell turnover. Apoptosis is well known to play a key role in maintaining homeostasis in continuously renewing tissues. We examined whether true apoptosis occurred in the normal olfactory epithelia of healthy adult guinea pigs using nucleic acid labeling. Subsequently, apoptosis was recognized in olfactory nerve cells, indicating that apoptosis might play a role in turnover of the olfactory epithelium.

Hypertrophic cardiomyopathy in patients with diabetes mellitus associated with mitochondrial tRNA(Leu)(UUR) gene mutation

Left ventricular function and morphology were assessed using M-mode echocardiography in 3 patients with diabetes mellitus associated with mitochondrial tRNA(Leu)(UUR) gene mutation, who were free of clinical, electrocardiographic, or thallium scan evidence of ischemic heart disease. Echocardiograms revealed hypertrophic cardiomyopathy in all 3 patients. Hypertrophy of the interventricular septum was mild in Cases 1 and 3 (12 and 13 mm, respectively) and severe in Case 2 (22 mm) (normal 7-10 mm). When they had neither signs nor symptoms suggestive of congestive heart failure, percentage fractional shortening (%FS), an index of wall motion of the left ventricle (normal > 28%), was normal in Cases 2 and 3 (28 and 32%, respectively) whereas it was slightly decreased in Case 1 (22%). In Case 1 with mild hypertrophy, the development of congestive heart failure was associated with a marked decrease in %FS to 13%; this patient responded well to diuretics and captopril and %FS rose to 22%. However, a mild decrease in %FS to 21% caused congestive heart failure in Case 2 with severe hypertrophy. His response to treatment was marginal. The present study indicates that mitochondrial DNA analysis should be done in patients with diabetic cardiomyopathy, and that sequential echocardiography is invaluable for the detection of hypertrophic cardiomyopathy and the management of subsequent myocardial dysfunction in patients with mitochondrial diabetes mellitus and cardiomyopathy.

Significance of detection of enterovirus RNA in myocardial tissues by reverse transcription-polymerase chain reaction

Enteroviruses are known to have association with human myocarditis and dilated cardiomyopathy (DCM). We screened biopsy specimens from patients with active myocarditis or DCM, and myocardial tissues from autopsy cases without cardiac diseases using polymerase chain reaction (PCR) gene amplification. Positive enteroviral signals were demonstrated from 4 of 5 patients with active myocarditis (80%), 7 of 42 patients with DCM(17%) and 3 of 27 autopsies (11%). Out of 7 PCR positive patients with DCM, 3 cases showed hypertrophy and disarray of cardiocytes, fibrosis in the interstitium, and a few inflammatory infiltrates. The remaining 4 cases with DCM and 3 PCR positive autopsy cases did riot exhibit histological findings compatible with those in myocarditis. Our results support the observations that enteroviruses are common aetiologic agents of myocarditis, and some cases of DCM. Our results also suggest the possibility that in some cases enteroviruses may persist in the myocardium without causing apparent pathological changes.

Efficient gene targeting in the filamentous fungus Alternaria alternata

To characterize homologous recombination of transforming DNA in the filamentous fungus Alternaria alternata, we have compared the frequencies of gene targeting by circular and linear DNA fragments in the fungus. The A. alternata BRM1 gene, which is an essential gene for melanin biosynthesis, was selected as a target locus. BRM1 targeting events are easily identified because loss of function leads to a change in mycelial color from black to light brown. We constructed targeting vectors by inserting 0.6 to 3.1 kb internal BRM1 segments into a plasmid containing the hygromycin B phosphotransferase gene. When circular plasmids were used, melanin-deficient (Mel-) transformants accounted for 30 to 80% of hygromycin B-resistant (HyR) transformants, correlating closely with the size of the BRM1 segment in the transforming DNA. Restriction enzyme digestion within the BRM1 region greatly enhanced the frequency of gene targeting: integration of the linear plasmids was almost completely attributable to homologous recombination, regardless of the size of the BRM1 segments. Plasmids carrying both BRM1 segments and rDNA segments were transformed into the fungus to examine the effect of the number of target copies on homologous recombination. Using the circular plasmids, Mel- transformants accounted for only 5% of HyR transformants. In contrast, when the linear plasmid produced by restriction enzyme digestion within the BRM1 segment was used, almost all transformants were Mel-. These results indicate that homologous integration of circular molecules in A. alternata is sensitive to the length of homology and the number of targets, and that double-strand breaks in transforming DNA greatly enhance homologous recombination.

[Exercise-nitroglycerine technetium-99m-2-methoxy isobutyl isonitrile tomoscintigraphic imaging for identifying diseased coronary vessels: comparison with thallium-201 standard exercise-redistribution study]

A same-day double injection protocol employing 99mTc-methoxy isobutyl isonitrile (MIBI) and myocardial single-photon emission computed tomography (SPECT) for detecting coronary heart disease (CAD) was assessed in 21 patients. Our exercise-nitroglycerin (NTG) MIBI study was performed as follows: 150 MBq 99mTc-MIBI was injected at peak exercise, and after 5 minutes 0.3 mg of NTG was sublingually administered. Then, SPECT was performed 1 hour later. Immediately after the 1st imaging, patients were injected of 750 MBq 99mTc-MIBI and were reimaged 1 hour later. Within 1 month, all patients were underwent standard exercise redistribution SPECT thallium (Tl) study. Of the 126 myocardial segments evaluated, 81 were judged as normal by both techniques, while the presence of stress defects were demonstrated in 37 segments (Agreement: 94%). Vessel sensitivities were 75% by MIBI and 67% by Tl. Specificities were 90% by MIBI and 93% by Tl. For the pattern of reversibility in myocardial segments with stress defects, the agreement was 73%. In conclusion, our exercise-NTG MIBI may be safely performed, giving results equivalent to those of standard stress-redistribution thallium studies.

[Myocardial SPECT with iodine-123-labeled beta-methyl-branched fatty acid in patients with angina pectoris]

To evaluate the usefulness of 123I-BMIPP as a tracer of fatty acid metabolism in patients with angina pectoris, we performed rest BMIPP myocardial SPECT and stress 201Tl SPECT in 20 patients with angina pectoris. BMIPP SPECT was evaluated in the defected regions with Tl redistribution. Abnormal findings in BMIPP were observed in 11 of 20 patients and in 14 of 29 myocardial segments with Tl redistribution. Such decreased uptake was observed more often in patients with multivessel disease (64% vs. 12%). In addition, the decreased BMIPP uptake was seen more often in the segments exhibiting hypokinesis than the segments showing with normal wall motion. Thus, BMIPP imaging may be available to detect myocardial ischemia, particularly in patients with severe coronary disease.

[Clinical usefulness of the quantitative assessment of exercise thallium-201 myocardial imaging in patients with ischemic heart disease]

To clarify the significance of the quantitative analysis of the area of decreased activity in exercise thallium-201 myocardial imaging, 42 patients with one vessel disease (20 patients with angina pectoris without myocardial infarction, 22 patients with old myocardial infarction: MI) were evaluated by exercise thallium scan and compared with clinical findings and wall motion assessed by left ventriculography (LVG). Patients with MI were divided into two groups by LVG (Mild MI: MI with only hypokinesis on LVG, Severe MI: MI with akinesis or dyskinesis on LVG). The degree of defected area was expressed by the ratio of the counts of defected area to the normal area (Relative Activity: RA). RA of the area of decreased activity in patients with angina was higher than that of patients with MI (77.5 +/- 4.59% vs. 65.7 +/- 7.85%, p < 0.05). RA of the area of decreased activity in patients with mild MI was higher than that of patients with severe MI (69.5 +/- 4.78% vs. 61.3 +/- 8.45%, p < 0.01). The above results suggest that the regional thallium-201 uptake ratio in the scintigram may help to differentiate viable zones from necrotic ones and detect the degree of MI.

Improvement of severe heart failure with corticosteroid therapy in a patient with myocardial sarcoidosis

A patient presented with severe heart failure due to myocardial sarcoidosis. Sarcoidosis was diagnosed by biopsy of the skin and uptake of gallium-67 in the heart. We treated the patient with corticosteroids and succeeded in improving her condition. We assume that this was a rare case in which severe heart failure improved following with steroid therapy.

Hematoma of the interatrial septum associated with complete atrioventricular block

A 70-year-old man who had been treated for tongue cancer began to suffer from repeated syncopal attacks. His electrocardiogram indicated complete atrioventricular block. A permanent pacemaker was implanted. He was well for about 2 years after which time he developed dyspnea, suffered from general fatigue, and then suddenly died. A postmortem examination revealed a hematoma approximately 4 x 4. cm in size in the interatrial septum, connected to a noncoronary sinus and rupture of the noncoronary leaflet, which compressed the tricuspid and aortic valves. This hematoma might have been related to the conduction disturbance caused by destructive compression on the conduction system, and his death by the rupture of the noncoronary leaflet.

The clinical and prognostic significance of dipyridamole Tl-201 emission computed tomography in patients with dilated cardiomyopathy

To clarify the clinical significance of regional myocardial perfusion abnormality of the left ventricle in dilated cardiomyopathy (DCM), 20 patients with DCM underwent dipyridamole Tl-201 emission computed tomography (ECT). The subjects were divided into 2 groups: group 1 had (n = 9) reversible defects and group 2 (n = 11) had persistent defects only. Group 2 patients significantly advanced heart failure and significantly poorer prognoses than group 1 (55% vs 11% in 2 years survival rate, p less than 0.05). The echocardiographic left ventricular end-diastolic dimension was larger in group 2 than group 1 (68.3 +/- 8.2 mm vs 61.9 +/- 4.0 mm, p less than 0.05) and % fractional shortening was smaller in group 2 than group 1 (18.0 +/- 4.5% vs 24.5 +/- 6.9%, p less than 0.05). Moreover, 12 of the 13 segments with reversible defect showed fairly well preserved left ventricular wall motion, whereas 35 of 58 segments with persistent defect had severely impaired wall motion (1/13 vs 35/58, p less than 0.01). Dipyridamole Tl-201 ECT demonstrated conclusively that the two types of defects (reversible and persistent) are useful to evaluate not only the abnormal myocardial perfusion but also myocardial damage and the prognosis in DCM.

[Assessment of regional wall motion and myocardial flow in patients with dilated cardiomyopathy using Tl-201 SPECT during dobutamine infusion]

The present study clarified the relationship between wall motion and myocardial flow in dilated cardiomyopathy (DCM). Two-dimensional echocardiography (2-DE) was performed in 14 patients before and after dobutamine (DOB) drip infusion (8 micrograms/kg/min). Thallium-201 emission computed tomography (ECT) was performed after dobutamine infusion and three hours thereafter. The left ventricle was divided into nine segments. In each segment, the degrees of defects were scored from 0 (normal) to 3 (complete defect), and the severity of wall motion abnormalities was scored from 0 (normal) to 3 (akinesis) by visual inspection. 1. Perfusion defects on ECT images were observed during dobutamine infusion in all patients. Redistribution was observed in nine of 14 (64%) patients. 2. During infusion, 38 (81%) of 47 segments without defects showed normal wall motion, but 44 (86%) of 51 segments with defects showed wall motion abnormalities. 3. Redistribution was observed in 18 (35%) of 51 segments, and these segments showed lower incidence of wall motion abnormalities as compared to the other segments (94% vs 45%, p less than 0.001). 4. After infusion, the segments with redistribution frequently showed improved wall motion as compared to the other segments (56% vs 18%, p less than 0.05). These results indicate that redistribution on the ECT image is observed in some patients with dilated cardiomyopathy after dobutamine administration. This may be due to the capacity of the drug to increase myocardial flow in proportion to the increase of oxygen demand.

[Hypertrophic non-obstructive cardiomyopathy assessed by dipyridamole thallium single photon emission computed tomography: comparisons with hypertrophic cardiomyopathy with a dilated heart]

Thallium-201 (Tl) single photon emission computed tomography (SPECT) after dipyridamole infusion (0.56 mg/kg) was performed in 23 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) and in seven patients with HCM simulating dilated cardiomyopathy (HCM-DCM) to clarify the mechanism and clinical significance of decreased coronary vasodilatory reserve. The coronary vasodilatory reserve in the hypertrophied area assessed by SPECT was compared with the findings of echocardiography, left ventriculography and endomyocardial biopsy. 1. Eleven patients with HNCM had no perfusion defects in the hypertrophied area (group I), but the other 12 patients (52.2%) had such defects (group II). All seven patients with HCM-DCM had perfusion defects in the anterior or septal walls (group III). Redistribution was observed in 11 of the 12 patients in group II and in three of the seven patients in group III. 2. The regional washout rate was relatively low in the upper septum in group II and in the anterior wall and upper septum in group III. Thus, coronary vasodilatory reserve in the hypertrophied area was decreased in groups II and III. 3. Echocardiographically, the degree of hypertrophy did not differ between groups I and II, but the latter had significantly greater left ventricular diastolic dimension (42.3 mm vs 49.5 mm: p less than 0.05) and lower percent fractional shortening (%FS) (43.7% vs 35.6%: p less than 0.05). However, group III showed thinner left ventricular wall, much greater diastolic dimension (60.9 mm vs 49.5 mm: p less than 0.05), and lower %FS (24.0% vs 35.6%: p less than 0.05) than did those of group II. 4. On left ventriculography, those in group II showed larger left ventricular end-diastolic volume index (93.9 ml/m2 vs 79.7 ml/m2: p less than 0.05) than that of group I. Left ventricular ejection fraction showed the same tendency, but this was not statistically significant. 5. On endomyocardial biopsy, the specimens of the patients in group II had significantly higher percent fibrosis than did those of group I (11.4% vs 6.8%: p less than 0.05). These findings suggest that the mechanism of decreased coronary vasodilatory reserve in the hypertrophied area may be related to myocardial fibrosis, and this decrease may induce left ventricular dysfunction and compensatory dilatation.

[Tl-201 single-photon emission computed tomography for clinical assessment of dilated cardiomyopathy]

In some cases of dilated cardiomyopathy (DCM) perfusion defects are demonstrable by Tl-201 imaging at rest. This study clarified the mechanism by which the Tl scan can show myocardial perfusion defects in patients with DCM by means of Tl-201 single-photon emission computed tomography (ECT) utilizing a rotating gamma camera to assess three-dimensional T1 distribution in the myocardium. Thirteen patients with DCM were studied by conventional planar and ECT imaging, and the degree of defects was determined visually. Perfusion defects were observed in 11 of 13 cases (85%) by planar imaging and in all 13 (100%) by ECT imaging. The mean defect score was higher in ECT than in planar imaging (4.15 +/- 1.46 vs 2.23 +/- 1.46, p less than 0.025). A comparative study of defect scores and left ventricular ejection fractions (EF) using gated cardiac blood pool scans established a negative correlation on ECT imaging (r= -0.64), and no correlation on planar imaging (r= -0.38). There was no statistically significant correlation between perfusion defects on planar imaging and regional wall motion abnormalities as observed by two-dimensional echocardiography (2-DE). In contrast, most of the segments with severe defects (defect score greater than or equal to 2) on ECT images showed high grade wall motion abnormalities on 2-DE. Both perfusion defects and wall motion abnormalities in DCM may be closely related to the fibrosis or scar formation in the myocardium. These results indicated that T1-201 myocardial scintigraphy, especially ECT imaging, is of great value in the clinical assessment of patients with DCM.

[Clinical usefulness of exercise-nitroglycerin myocardial imaging using dual administration of thallium-201]

In order to differentiate transient myocardial ischemia from infarction, the delayed thallium-201 myocardial imaging (redistribution image) is widely utilized, however, the precise mechanism of redistribution remains unsolved. In the present study, we proposed a new method to elucidate myocardial ischemia on images. In normal subjects, patients with old myocardial infarction (OMI) without angina pectoris (AP) and patients with AP, 1.4 mCi of thallium-201 (Tl-201) was intravenously injected at the peak exercise, and immediately myocardial images were obtained in the three projections. Then, 0.3 mg of nitroglycerin (NTG) was sublingually given, and 0.6 mCi of Tl-201 was readministered. NTG myocardial images were analyzed in the left anterior oblique projection and evaluated visually and quantitatively. There was no significant difference in the relative activity on exercise to NTG images in normal subjects and patients with OMI, while patients with AP showed increased activity on exercise to NTG images. Furthermore, the increase in relative activity done by the exercise-nitroglycerin study was greater than that by the conventional exercise-redistribution study in patients with AP. It was concluded that a new method in the present study is able to image myocardial ischemia distinctly and could be useful in clinical studies.