Similar subunit interactions contribute to assembly of clathrin adaptor complexes and COPI complex: analysis using yeast three-hybrid system

Clathrin adaptor protein (AP) complexes are heterotetramers composed of two large, one medium, and one small subunits. By exploiting the yeast three-hybrid system, we have found that an interaction between the two large subunits of the AP-1 complex, gamma-adaptin and beta1-adaptin, is markedly enhanced in the presence of the small subunit, sigma1. Similarly, two large subunits of the AP-4 complex, epsilon-adaptin and beta4-adaptin, are found to interact with each other only in the presence of the small subunit, sigma4. Furthermore, we have found that an interaction between two large subunits of the COPI F subcomplex, gamma-COP and beta-COP, is detectable only in the presence of zeta-COP. Because these COPI subunits have common ancestral origins to the corresponding AP subunits, these three-hybrid data, taken together with the previous two-hybrid data, suggest that the AP complexes and the COPI F subcomplex assemble by virtue of similar subunit interactions.

Homocysteine inhibits angiogenesis in vitro and in vivo

Homocysteine has been reported to inhibit endothelial cell proliferation, which is closely related to angiogenesis. However, the relationship between homocysteine and angiogenesis is unknown. To clarify whether homocysteine would inhibit angiogenesis in vitro and in vivo, we examined the effect of homocysteine on tube formation by bovine aortic endothelial cells (BAECs) and by human microvessel endothelial cell-1 (HMEC-1) in vitro, and on angiogenesis in vivo using the chorioallantoic membrane (CAM) assay, as well as on BAEC proliferation and migration. Homocysteine, but not cysteine, inhibited BAEC proliferation, migration, and tube formation in a dose-dependent manner at concentrations from 0 to 10 mM. Homocysteine also inhibited tube formation by HMEC-1s. In these assay, 50% inhibition was induced by about 1 mM homocysteine. In the in vivo CAM assay, 0, 10, 100, 500, and 1000 microgram homocysteine induced an avascular zone by 0, 0, 16.7, 53.3 and 76.5%, respectively, also showing a dose-dependent effect. It was suggested that homocysteine inhibited angiogenesis by preventing proliferation and migration of endothelial cells.

Tumor necrosis factor-alpha (TNF-alpha) plays a protective role in acute viralmyocarditis in mice: A study using mice lacking TNF-alpha

BACKGROUND

It has been reported that tumor necrosis factor-alpha (TNF-alpha) is expressed in the heart with viral myocarditis and that its expression aggravates the condition. The pathophysiological effects of TNF-alpha on viral myocarditis, however, have not been fully elucidated.

METHODS AND RESULTS

To investigate the role of TNF-alpha in the progression of viral myocarditis, we used TNF-alpha gene-deficient mice (TNF-alpha(-/-)) and induced acute myocarditis by infection with encephalomyocarditis virus (EMCV). The survival rate of TNF-alpha(-/-) mice after EMCV infection was significantly lower than that of TNF-alpha(+/+) mice (0% versus 67% on day 14). Injection of recombinant human TNF-alpha (0.2 to 4.0 microg/mouse IV) improved the survival of TNF-alpha(-/-) mice in a dose-dependent manner, indicating that TNF-alpha is essential for protection against viral myocarditis. The levels of viral titer and viral genomic RNA of EMCV in the myocardium were significantly higher in TNF-alpha(-/-) than in TNF-alpha(+/+) mice. Histopathological examination showed that the inflammatory changes of the myocardium were less marked in TNF-alpha(-/-) than in TNF-alpha(+/+) mice. Immunohistochemical analysis revealed that the levels of immunoreactivity of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in the myocardium were decreased in TNF-alpha(-/-) mice compared with TNF-alpha(+/+) mice.

CONCLUSIONS

These observations suggested that TNF-alpha is necessary for adhesion molecule expression and to recruit leukocytes to inflammatory sites, and thus, the lack of this cytokine resulted in failure of elimination of infectious agents. We concluded that TNF-alpha plays a protective role in the acute stage of viral myocarditis.

Identification and characterization of novel isoforms of COP I subunits

COP I-coated vesicles are involved in vesicular trafficking in the early secretory pathway. The COP I coat is composed of seven subunits, alpha-, beta-, beta'-, gamma-, delta-, epsilon-, and zeta-COPs. Evidence suggests, however, that there may be isoforms of the COP I subunits. In the present study, we identified homologs of gamma-COP (gamma2-COP; original gamma-COP is referred to as gamma1-COP in this paper) and of zeta-COP (zeta2-COP; original zeta-COP is referred to as zeta1-COP). gamma1- and gamma2-COPs, and zeta1- and zeta2-COPs share 80 and 75%, respectively, of amino acids. mRNAs for gamma2-COP and zeta2-COP are expressed ubiquitously, suggesting their fundamental role in cellular function. Immunofluorescence analysis shows that gamma2-COP and zeta2-COP are colocalized with beta-COP in the paranuclear cis-Golgi region. Yeast two-hybrid analysis indicates that gamma1- and gamma2-COPs can directly, albeit promiscuously, interact with zeta1- and zeta2-COPs. Like gamma1-COP, gamma2-COP can form a complex with beta-COP in vivo. The gamma1-COP-containing and gamma2-COP-containing complexes can similarly interact with the cytoplasmic domain of p23. These results indicate that gamma2-COP and zeta2-COP can form a COP I-like complex in place of gamma1-COP and zeta1-COP, respectively, and suggest that the COP I complex and the COP I-like complex are functionally redundant.

Considerable time from the onset of plaque rupture and/or thrombi until the onset of acute myocardial infarction in humans: coronary angiographic findings within 1 week before the onset of infarction

BACKGROUND

It has been thought that the thrombi and bleeding in plaques that occur after plaque rupture or endothelial damage from vessels with mild stenosis suddenly occlude the lumen and cause acute myocardial infarction (AMI). However, our hypothesis is that thrombi and bleeding may not suddenly occlude the lumen.

METHODS AND RESULTS

The study group consisted of 20 patients who had coronary angiograms performed within 1 week (3+/-3 days) before AMI and 20 control patients who had coronary angiograms performed 6 to 18 months (282+/-49 days) before AMI. The features of infarct-related coronary segments (IRCS) at 3 days before AMI were the presence of a significant stenosis of >50% (95% in incidence and 71+/-12% diameter stenosis) and Ambrose's type II eccentric lesions (plus multiple irregularities), an indicator of plaque rupture and/or thrombi (60% [70%]), and the features at 1 year before AMI were mild stenosis of <50% (95% incidence and 30+/-18% diameter stenosis) with rare Ambrose's type II eccentric lesions (plus multiple irregularities) (10% [10%]). The same relation was observed in each of the 4 subgroups with Q-wave infarction, non-Q-wave infarction, preceding effort angina within 1 month before AMI, and no preceding effort angina.

CONCLUSIONS

The appearance of marked progression and Ambrose's type II eccentric lesion on coronary angiograms 3 days before AMI suggests the presence of a considerable time from the onset of plaque rupture and/or thrombi until the onset of AMI. These features may be predictors of AMI. The concept provides new insight into the mechanism and prevention of human AMIs.

Metastatic pulmonary epithelioid hemangioendothelioma with peculiar radiographic features

We report a case of a pulmonary epithelioid hemangioendothelioma presenting as a solitary pulmonary nodule with subsequent systemic spread, including histologically documented gingival metastasis. Chest radiography and computed tomography at initial evaluation showed a solitary 2 cm pulmonary nodule, associated with pleural indentation and vascular convergence. The tumor later spread systemically, including multiple pulmonary nodules, bilateral pleural effusions, and gingival swelling and erosion. A biopsy of the gingival lesion showed histologic features identical to that of the lung biopsy.

Mode and role of cell death during progression of atherosclerotic lesions in hypercholesterolemic rabbits

Two cell types, macrophages and smooth muscle cells (SMCs), play important roles in the development of atherosclerotic lesions. Both contribute to the formation of the lesions not only by their presence but also by taking in or releasing extracellular substrates during life and at death. The present study aimed to elucidate their turnover, focusing on the detailed description of the modes of death in each cell type, and the roles of their death in the progression from early into advanced atherosclerotic lesions. Ascending aortas were obtained from New Zealand white male rabbits fed a diet with 1% cholesterol for 3 months (3-M group, n= 6) and 6 months (6-M group, n = 6). They were histologically examined, and the cell death was checked by in situ nick end-labeling (TUNEL), using a Taq polymerase-based in situ ligation assay with/without combination of immunohistochemistry, electron microscopy (EM), and TUNEL at the EM level. Intimal hyperplasia and luminal stenosis advanced with increased dietary interval, and the aortic intima of the 3-M group consisted of histological types I-III atherosclerotic lesions, whereas that of the 6-M group included types III-V. Along with the progression, the cellular population decreased, but the area of fibrosis increased. The percentage area of macrophages declined (from 60% +/- 5% to 23% +/- 2%), but that of SMCs increased (from 5% +/- 1% to 10% +/- 2%). The positive cells for in situ ligation were less frequent in the 6-M group (0.05% +/- 0.01%) than in the 3-M group (0.2% +/- 0.04%), which was due to a decrease in SMCs positive for in situ ligation. The frequency of TUNEL-positive cells was higher than that of in situ ligation-positive cells in both groups, suggesting that cell death involved not only apoptosis but also oncosis. This was confirmed using EM: cell death occurred via both apoptosis and oncosis. EM-TUNEL positively labeled not only apoptotic but also some oncotic nuclei. Death of macrophages and SMCs involves both apoptosis and oncosis in the aortic intima of hypercholesterolemic rabbits. Decline in the dying rate of SMCs might be associated with the formation of SMC-rich and collagen-rich lesions in the late advanced stage of atherosclerosis, although such a cause-effect relationship is to be further confirmed.

Adaptor gamma ear homology domain conserved in gamma-adaptin and GGA proteins that interact with gamma-synergin

We identified a novel family of proteins that have a VHS domain and an AGEH (adaptor gamma ear homology) domain that is homologous to the ear domain of the gamma-adaptin subunit of the AP-1 clathrin adaptor. When overexpressed, the proteins, called GGA1, GGA2, and GGA3, localized to the trans-Golgi network (TGN) and often caused fragmentation and vacuolation of the compartment. Yeast two-hybrid analysis showed that the AGEH domains of the GGA proteins as well as those of gamma-adaptins are able to interact with gamma-synergin, which was previously shown to localized in the TGN region and interact with gamma-adaptin. Furthermore, gamma-synergin and either of the GGA proteins coexpressed were colocalized in the TGN region. These results suggest that the GGA proteins regulate the function of the TGN or membrane trafficking from this compartment and that the AGEH domains of GGAs and gamma-adaptins, like the ear domain of alpha-adaptin, are involved in interaction with molecules that modulate their functions.

[High molecular-weight Bence Jones protein deposits in the kidney of a patient with plasma cell dyscrasia]

A 70-year-old man was admitted to our hospital because of edema of the face and legs, proteinuria, and hypoproteinemia. We made a diagnosis of nephrotic syndrome. Immunoelectrophoresis of the patient's serum and urine disclosed a small amount of kappa type Bence-Jones protein (BJP) in the fast-gamma area. A renal biopsy showed nodular expansion of mesangium with deposition of space kappa-light chain in the mesangial area. Light chain deposition disease was diagnosed. Western blotting analysis disclosed that the patient's BJP molecules had a molecular mass of 66 KDa, and were composed of two kappa chains of 33 KDa. Bone marrow aspiration revealed dysplastic plasma cells, and Western blotting analysis of an extract of these cells detected BJP-kappa with a molecular mass of 33 Kda. This BJP was larger than normal, indicating the possibility of abnormal structure. Structural abnormalities may be responsible for tissue precipitation of the kappa light chain.

Cardiac sympathetic denervation from the early stage of Parkinson's disease: clinical and experimental studies with radiolabeled MIBG

Autonomic disorder is not infrequent in patients with akinetic-rigid syndromes, including idiopathic Parkinson's disease. In the advanced stage of Parkinson's disease, abnormal blood pressure responses, such as orthostatic hypotension and abnormal circadian blood pressure rhythm, may occur. Few cases of reduced 123I-metaiodobenzylguanidine (MIBG) accumulation in the heart or limbs of Parkinson's disease patients have been reported. However, whether reduced accumulation is caused by damage to the postganglionic sympathetic nervous system or by central autonomic failure corresponding to abnormalities in blood pressure regulation is unknown.

METHODS

We evaluated sympathetic denervation in 32 Parkinson's disease patients using 123I-MIBG cardiac scintigraphy and compared the findings with those for autonomic dysfunction detected by orthostatic hypotension and diurnal blood pressure variation. Cardiac 125I-MIBG accumulation was also determined in an experimental model of Parkinson's disease using mice pretreated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

RESULTS

Cardiac 123I-MIBG accumulation 15 min after injection and 4 h after injection was markedly reduced in the Parkinson's disease patients (heart-to-mediastinum ratio: 1.58 +/- 0.37 and 1.33 +/- 0.28, respectively) compared with 7 healthy volunteers (2.42 +/- 0.27 and 2.60 +/- 0.15, respectively). This reduction was observed even at the earlier stages of physical activity or disease duration and also in patients with normal blood pressure response and variation, indicating that the marked decrease in cardiac 123I-MIBG accumulation may be a special feature of Parkinson's disease. Pretreatment with a total dose of 100 mg/kg MPTP, which is the standard dose used to destroy the dopaminergic neurons in models of Parkinson's disease, significantly reduced cardiac 125I-MIBG accumulation in C57BL/6 mice. Interestingly, the reduction of 125I-MIBG accumulation was still significant when MPTP was reduced to 5 mg/kg. These findings indicated that the postganglionic sympathetic nerves may be damaged by MPTP or unknown toxic substrates in experimental or human Parkinson's disease during the early stage, because dopaminergic neurons and sympathetic nerves are substantially similar in their plasma membrane transporters.

CONCLUSION

Cardiac scintigraphy with 123I-MIBG may be used as a new imaging approach in the diagnosis and characterization of akinetic-rigid syndromes, especially Parkinson's disease.

Granulocyte accumulation in ischemic/reperfused myocardium: assessment with a technetium-99m-labeled antigranulocyte monoclonal antibody in the dog

This study tested the usefulness of technetium-99m-labeled antigranulocyte monoclonal antibody BW250/183 (AGMAb) for identifying granulocyte accumulation in ischemic/reperfused canine myocardium. In dogs with 90 minutes coronary artery occlusion and 180 minutes reperfusion (n = 8), ischemic/reperfused myocardial samples demonstrated 8.5 +/- 2.4 times more Tc-99m-AGMAb accumulation than nonischemic samples. Dogs given Tc-99m-labeled nonspecific human immunoglobulin instead of Tc-99m-AGMAb (n = 3) had about half as much accumulation (4.5 +/- 1.6, P < .05). Ex vivo myocardial imaging of Tc-99m-AGMAb demonstrated marked uptake in infarcted regions identified by absent triphenyl tetrazolium chloride staining. The amount of uptake was inversely related to the severity of ischemia (determined by radioactive microspheres) and directly correlated with tissue myeloperoxidase activity, a specific marker of granulocyte accumulation. No increase in Tc-99m-AGMAb uptake occurred in dogs with 90 minutes ischemia and no reperfusion (n = 3) or 15 minutes ischemia and 180 minutes reperfusion (n = 2). In conclusion, Tc-99m-AGMAb is taken up in reperfused infarcted myocardium by both nonspecific and specific mechanisms. Because the amount of uptake reflects myocardial granulocyte accumulation, Tc-99m-AGMAb combined with nuclear imaging techniques may be useful for studying inflammatory processes in the heart in experimental animal models and human beings.

Apoptosis and overexpression of bax protein and bax mRNA in smooth muscle cells within intimal hyperplasia of human radial arteries : analysis with arteriovenous fistulas used for hemodialysis

There is a type of arteriosclerosis with remodeling of middle-size arteries in which intimal hyperplasia of smooth muscle cells (SMCs) plays the main role, and there are few macrophages, T lymphocytes, and foam cells. It is unknown whether apoptosis and the expression of Bax, an inducer of apoptosis, are increased according to the progression of this type of human arteriosclerosis, which is different from so-called atherosclerosis. Bax heterodimerizes with Bcl-2, an inhibitor of apoptosis, and the ratio of Bax to Bcl-2 determines cellular apoptosis or survival. Thus, we investigated apoptosis and the expressions of Bax, bax mRNA, and Bcl-2 in human arteriovenous (AV) fistulas used for hemodialysis, a representative of arteriosclerosis of the aforementioned type. The material was 20 radial arteries obtained from 20 patients with chronic renal failure undergoing AV shunt surgery. SMCs, macrophages, and T lymphocytes were immunohistochemically identified at the light microscopic (LM) level. Apoptosis was detected by in situ terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-dUTP nick end labeling (TUNEL) at both the LM and electron microscopic (EM) level. Cell proliferating activity was estimated by proliferating cell nuclear antigen (PCNA). Bax and Bcl-2 were detected by immunohistochemistry and Western blot analysis. Expression of bax mRNA was detected by in situ hybridization. LM TUNEL-positive cells in both the intima and media were significantly increased according to the percent stenosis of the vessels. EM analysis revealed that ultrastructures of apoptotic SMCs were seen in both synthetic and contractile phenotypes. Their frequency of occurrence in the intima and media were greater in those vessels with >50% stenosis than in those with <50% stenosis (5.2+/-0.7% versus 1.0+/-0.3% in the intima and 2. 1+/-0.5% versus 0.2+/-0.1% in the media). The proportion of apoptotic SMCs with ruptured plasma membranes was greater than that of apoptotic SMCs with intact membranes in the intima of the former (4.1+/-0.6% versus 1.1+/-0.1%). Only those SMCs with apoptotic ultrastructures had TUNEL-positive nuclei with moderate or marked accumulation of immunogold particles at the EM level. However, ultrastructures of oncosis (primary necrosis) were not observed. Immunohistochemical analyses showed significant positive correlations between percent stenosis of vessels and the percentage of either PCNA-positive intimal cells or Bax-positive areas in the intima and media. Bcl-2-positive cells were not observed in the intima but mainly in the outer media. The percentage of Bcl-2-positive medial cells was definitely decreased at an early stage after formation of the AV fistula but did not change according to the duration of hemodialysis or the progression of arteriosclerosis. Western blot analysis of Bax or Bcl-2 and in situ hybridization of bax mRNA confirmed the immunohistochemical data. Thus, regulation of cellularity in intimal hyperplasia of SMCs in human arteriosclerosis with remodeling is mediated by proliferation and apoptosis but not oncosis. The apoptosis is probably induced by an increase in the Bax to Bcl-2 ratio.

Process of progression of coronary artery lesions from mild or moderate stenosis to moderate or severe stenosis: A study based on four serial coronary arteriograms per year

BACKGROUND

The process of progression in coronary artery disease is unknown.

METHODS AND RESULTS

The subjects were 36 patients with 36 objective vessels with clinically significant progression of coronary artery disease (>/=15% per year) in whom 4 serial coronary arteriograms (CAGs) were performed at intervals of approximately 4 months in a 1-year period. The degree of progression of percent stenosis between each of 2 serial CAGs was classified as marked (M: >/=15%), slight (S: 5% to 14%), and no progression (N: <5%). From the pattern of progression, the 36 vessels were classified as 14 type 1 vessels with marked progression (N-->N-->M in 13 vessels and S-->S-->M in 1 vessel) and 22 type 2 vessels without marked progression (S-->S-->S in 18 vessels, N-->S-->S in 4). Percent stenosis at the first, second, third, and final CAGs was 44+/-14%, 46+/-13%, 46+/-13%, and 88+/-10% (P<0.05 versus first CAG) in type 1 vessels and 44+/-11%, 50+/-9%, 59+/-9%, and 67+/-9% in type 2 vessels (P<0.05 for second, third, and final CAGs versus first CAG). Type 1 vessels featured the sudden appearance of severe stenosis due to marked progression, angina pectoris, or myocardial infarction (71%) and Ambrose type II eccentric lesions indicating plaque rupture or thrombi (57%). Type 2 vessels featured continuous slight progression of stenosis with smooth vessel walls; angina pectoris (14%) occurred when the percent stenosis reached a severe level. An increase in serum C-reactive protein was observed only in the type 2 vessel group, which suggests a relation between continuous slight progression and inflammatory change.

CONCLUSIONS

Two types of stenosis progression provide a new insight into the mechanism of coronary artery disease.

Fifteen-year follow-up of a heterozygous Fabry's disease patient associated with pre-excitation syndrome

A 47-year-old woman with heterozygous Fabry's disease with pre-excitation syndrome has been followed up for 15 years. Diagnosis was confirmed by the typical electron microscopic feature of the endomyocardial specimen and a decreased plasma alpha-galactosidase activity. As the disease progressed, the interventricular septum thickened from 11 to 17 mm as measured by echocardiography, while the AH interval was prolonged from 80 to 140 msec. In Fabry's disease, the PR interval has been reported to be variable from short PR to AV block. Therefore, this case may be helpful to understand the time course in the AV conduction abnormalities with the progression of Fabry's disease.

Washout of I-123 meta-iodobenzylguanidine for assessing cardiac sympathetic activity with progression of hypertension in Dahl salt-sensitive rats

BACKGROUND

To evaluate cardiac sympathetic activity, a simple method should be developed to replace such complex methods as the spillover rate of tritiated norepinephrine (3H-norepinephrine) or microneurography of sympathetic nerve activity. The goal of this study is to evaluate cardiac sympathetic activities by analyzing the washout of I-123 meta-iodobenzylguanidine (123I-MIBG), a radiolabeled norepinephrine analogue, in Dahl salt-sensitive (DS) rats as it relates to the progression of hypertension.

METHODS AND RESULTS

Dahl salt-resistant (DR) rats and DS rats were fed an 8 % salt diet starting at age 5 weeks. Marked hypertension and cardiac hypertrophy developed in the DS rats, whereas DR rats remained normotensive. Then the time-activity curves of 123I-MIBG from 15 to 200 minutes were obtained from both DS and DR strains at ages 8, 11, and 13 weeks using dynamic scintigraphic analysis. We also examined the nonneuronal washout of 123I-MIBG using dynamic scintigraphic studies in desipramine pretreated normal rats. In the preliminary study with desipramine pretreatment, the majority of the nonneuronal 123I-MIBG washout occurred by 90 minutes after injection. Therefore the late-phase washout in the control rats was found to reflect the neuronal washout. We then applied exponential curve fitting to the time activity curves acquired in the 90- to 200-minute period after 123I-MIBG injection in both DR and DS rats. When we compared the coefficients of these washout curves in the DS and DR rats as an index of cardiac sympathetic activities, the coefficient values remained high during all stages in DS rats, whereas they decreased with age in DR rats.

CONCLUSION

Measurement of late-phase 123I-MIBG washout may be a useful tool for assessing the change in sympathetic activity in the progression of hypertension without the influence of extraneuronal washout of 123I-MIBG and left ventricular hypertrophy.

Intermolecular and interdomain interactions of a dynamin-related GTP-binding protein, Dnm1p/Vps1p-like protein

Dnm1p/Vps1p-like protein (DVLP) is a mammalian member of the dynamin GTPase family, which is classified into subfamilies on the basis of the structural similarity. Mammalian dynamins constitute the dynamin subfamily. DVLP belongs to the Vps1 subfamily, which also includes yeast Vps1p and Dnm1p. Typical structural features that discriminate between members of the Vps1 and dynamin subfamilies are that the former lacks the pleckstrin homology and Pro-rich domains. Dynamin exists as tetramers under physiological salt conditions, whereas under low salt conditions, it can polymerize into spirals that resemble the collar structures seen at the necks of constricted coated pits. In this study, we found that DVLP is also oligomeric, probably tetrameric, under physiological salt conditions and forms sedimentable large aggregates under low salt conditions. The data indicate that neither the pleckstrin homology nor Pro-rich domain is required for the self-assembly. Analyses using the two-hybrid system and co-immunoprecipitation show that the N-terminal region containing the GTPase domain and a domain (DVH1) conserved across members of the dynamin and Vps1 subfamilies, can interact with the C-terminal region containing another conserved domain (DVH2). The data on the interdomain interaction of DVLP is compatible with the previous reports on the interdomain interaction of dynamin. Thus, the self-assembly mechanism of DVLP appears to resemble that of dynamin, suggesting that DVLP may also be involved in the formation of transport vesicles.

[Mechanism of acute coronary syndrome studied with coronary arteriograms]

Numbers of studies using the coronary arteriograms (CAG) have been reported on the mechanism of the acute coronary syndrome (ACS) since 1980. DeWood et al. have shown that the rate of total occlusion in the culprit lesions gradually decreases as the interval from attack to CAG increases, suggesting that the occlusion is total or subtotal at the onset of acute myocardial infarction (AMI). Additionally, the stenosis is significantly mild in unstable angina compared with non-Q AMI. Ambrose et al. classified the morphology of the culprit lesions on CAG and revealed that their type II eccentric lesion or multiple irregularities, which are considered to be related to plaque rupture with or without thrombus, are more common in ACS than the other morphologies. The concept of ACS by Fuster et al. is substantially based on these angiographical findings. Little et al. reported that the pre-existing stenosis 1-2 years before the onset of AMI is mostly mild to moderate, indicating that the prediction of future AMI by CAG findings is of difficulty. Our study suggested the stenosis deteriorates abruptly and reached severe level in some cases just before the attack of ACS. Therefore, the continuous effort is needed to clarify the mechanism of the progression of coronary lesions which result in ACS.

Identification and characterization of novel clathrin adaptor-related proteins

We have identified a human approximately 87-kDa protein, designated as gamma2-adaptin, that is similar to gamma-adaptin (called gamma1-adaptin in this paper), a large chain of the AP-1 clathrin-associated adaptor complex, not only in the primary structure (60% amino acid identity) but also in the domain organization. Northern blot analysis has shown that its mRNA is expressed in a variety of tissues. Analysis using a yeast two-hybrid system has revealed that, similarly to gamma1-adaptin, gamma2-adaptin is capable of interacting not only with the sigma1 chain (called as sigma1A in this paper), the small chain of the AP-1 complex, but also with a novel sigma1-like protein, designated as sigma1B, which shows an 87% amino acid identity to sigma1A; and that, unlike gamma1-adaptin, it is unable to interact with beta1-adaptin, another large chain of the AP-1 complex. Immunofluorescence microscopy analysis has revealed that gamma2-adaptin is localized to paranuclear vesicular structures that are not superimposed on structures containing gamma1-adaptin. Furthermore, unlike gamma1-adaptin, gamma2-adaptin is recruited onto membranes in the presence of a fungal antibiotic, brefeldin A. These data suggest that gamma2-adaptin constitute a novel adaptor-related complex that participates in a transport step different from that of AP-1.

Invasive pulmonary mucormycosis with rupture of the thoracic aorta

We report an acute myelogenous leukemia patient with mucormycosis who died of massive hemoptysis during antifungal therapy. The diagnosis was made postmortem and autopsy revealed that the pulmonary nodule consisting of mucorales protruded over the luminal surface of the aorta. Microscopic examination showed the invasion of mucor hyphae into the wall of the aortic arch. Surgical treatment may be indicated for patients with pulmonary mucormycosis refractory to amphotericin B therapy.

Pleomorphic adenoma of the trachea: a case report

Pleomorphic adenoma is the most common form of major salivary gland tumors,but it is exceedingly rare in the trachea. We present a case of pleomorphic adenoma of the trachea in an 80-years-old man. Chest three-dimensional CT demonstrated a bosselated mass with a lobulated surface arising from the membranous portion of the upper trachea. Transbronchoscopic biopsy from the mass showed a biphasic histologic appearance produced by a mixture of glandular structure and hyaline-like stroma. The pathological diagnosis was pleomorphic adenoma.

N-methyl-1-deoxynojirimycin (MOR-14), an alpha-glucosidase inhibitor, markedly reduced infarct size in rabbit hearts

BACKGROUND

N-methyl-1-deoxynojirimycin (MOR-14), an alpha-glucosidase inhibitor, reduces the glycogenolytic rate by inhibiting the alpha-1,6-glucosidase of glycogen-debranching enzyme in the liver, in addition to possessing an antihyperglycemic action by blocking alpha-1,4-glucosidase in the intestine. Because the reduction of the glycogenolytic rate may be one of the mechanisms of myocardial protection in ischemic preconditioning, the compounds inhibiting myocardial alpha-1,6-glucosidase may be protective against ischemic damage. Thus, we investigated whether MOR-14 could inhibit alpha-1,6-glucosidase and reduce the infarct size in rabbit hearts without collateral circulation.

METHODS AND RESULTS

MOR-14 dose-dependently decreased the alpha-1,6-glucosidase activity in rabbit heart extract. A tracer study demonstrated the myocardial uptake of a considerable amount of MOR-14 sufficient to fully inhibit alpha-1,6-glucosidase. To assess the infarct size-reducing effect of MOR-14, 54 rabbits were subjected to 30-minute coronary occlusion followed by 48-hour reperfusion. Preischemic treatment with 25, 50, and 100 mg/kg of MOR-14 dose-dependently reduced the infarct size (to 26+/-4%, 19+/-3%, and 14+/-2% of the area at risk, respectively), compared with the saline control (45+/-5%) without altering the blood pressure or heart rate. Another 40 rabbits given 100 mg of MOR-14 or saline 10 minutes before ischemia were euthanized at 10 or 30 minutes of ischemia for biochemical analysis. MOR-14 decreased the alpha-1,6-glucosidase activity to approximately 20% in vivo, reduced the glycogen breakdown, and attenuated the lactate accumulation at both 10 and 30 minutes of ischemia.

CONCLUSIONS

Preischemic treatment with MOR-14 preserved glycogen, attenuated the accumulation of lactate, and reduced the myocardial infarct size by 69%. This cardioprotective effect was independent of changes of blood pressure and heart rate or regional blood flow. It may be associated with alpha-1,6-glucosidase inhibition, because MOR-14 markedly decreased the alpha-1,6-glucosidase activity in the heart.

Cardiac sympathetic nerve function assessed by [131I]metaiodobenzylguanidine after ischemia and reperfusion in anesthetized dogs

BACKGROUND

Accumulation of 131I-labeled metaiodobenzylguanidine ([131I]MIBG), a radiolabeled norepinephrine analog, is reduced in infarcted myocardium, suggesting loss of cardiac sympathetic nerve viability. Histopathologic studies, however, indicate that the nerve endings ae morphologically intact. Experiments were therefore designed to determine the mechanism of reduced MIBG accumulation.

METHODS AND RESULTS

Desipramine, a specific blocker or neuronal norepinephrine reuptake, was used to separate the portions of total myocardial [131I]MIBG accumulation attributable to neuronal and nonneuronal uptake mechanisms. Sixteen dogs underwent circumflex coronary artery occlusion for 60 minutes followed by a 5-hour reperfusion. [131I]MIBG was injected intravenously 1 hour after reperfusion. The left ventricle was removed and incubated in triphenyltetrazolium chloride to identify infarcted and viable myocardium within the zone at risk. Preliminary studies in sham-operated dogs showed that pretreatment with desipramine (5 mg/kg) reduced [131I]MIBG accumulation 4 hours after injection to 38.9% of untreated controls. Chemical sympathectomy by topical phenol resulted in a similar decrease in [131I]MIBG accumulation (to 45.7% of normal), and desipramine did not produce further inhibition of [131I]MIBG accumulation over that produced by phenol alone, indicating that the inhibitory effect of desipramine on neuronal accumulation of [131I]MIBG was essentially complete. In dogs undergoing ischemia-reperfusion, myocardial samples from infarcted and viable postischemic areas showed 64.5% +/- 11.85 and 84.7% +/- 9.1% of normal [131I]MIBG activity, respectively (both, p < 0.01 vs normal area, n = 9). With desipramine pretreatment (n = 7), accumulation of [131I]MIBG decreased in all areas. Neuronal accumulation was reduced uniformly in infarcted, viable postischemic, and normal areas by 30% to 35% compared with sham-operated controls. In contrast, nonneuronal accumulation was only 39.3% in infarcted areas and 84.6% in viable postischemic areas compared with normal areas, and these decreases accounted entirely for the reduced total [131I]MIBG accumulation.

CONCLUSIONS

Reduced [131I]MIBG accumulation in infarcted myocardium after 60 minutes of ischemia and 5 hours of reperfusion is attributable to a deficit in nonneuronal accumulation and not to decreased accumulation by sympathetic nerves.

Structure and intracellular localization of mouse ADP-ribosylation factors type 1 to type 6 (ARF1-ARF6)

ADP-ribosylation factors (ARFs) are a family of small GTP-binding proteins that are proposed to be involved in the formation of coated transport vesicles. Although six ARF sequences have been reported in mammals to date, it has been unclear how many ARF members are present in a single organism. In this study, we provide the first direct evidence by cDNA cloning for the presence of all six ARF members in mouse. These proteins are highly conserved across mammalian species and Northern blot analysis revealed that mRNAs for all the members were expressed ubiquitously. Transfection of cells with epitope-tagged ARFs revealed that ARFs 1-3 displayed a perinuclear Golgi localization, while ARFs 4-6 appeared to be widely dispersed throughout the cytoplasm. These results suggest that although all the ARF proteins play fundamental and critical roles in cellular function, they are involved in different vesicular transport processes.

[Sarcoidosis in a patient with autoimmune hemolytic anemia]

A 65-year-old woman was admitted to our hospital because of severe anemia. A skin biopsy was done in January 1994 and sarcoidosis was diagnosed. Diffuse reticular shadows were seen in both lung fields on a chest X-ray film and mediastinal lymph node swelling was seen on a chest CT scan. She was followed as an outpatient and was not treated. She suddenly experienced vertigo and general fatigue in March 1995. Laboratory findings on admission were as follows: Hb 6.2 g/dl, MCV 115.9 fl, Ret 198%, LDH 732 IU/L, I-Bil 1.9 mg/dl, and Coombs' test was positive. Autoimmune hemolytic anemia was diagnosed, and she was treated with prednisolone (1 mg/kg). As of the time of this writing, she has no relapse of hemolytic anemia though prednisolone was discontinued 6 months ago.

Bone and brain involvement in a case of diffuse large B cell lymphoma associated with t(2;3)(p12;q27)

We report a 57-year-old male with non-Hodgkin's lymphoma (NHL) associated with t(2;3)(p12;q27). The patient showed bone lesions at presentation and brain involvement at relapse in addition to systemic lymph node swelling. Histological diagnosis was malignant lymphoma, diffuse, large cell, immunoblastic, plasmacytoid. Chromosome analysis revealed t(2;3) which is a variant type of t(3;14)(q27;q32). Fluorescence in situ hybridization (FISH) analysis disclosed splits of signals of BCL-6 gene. Among the cases reported in the literature, the common feature of t(2;3)(p11 or p12;q27) was diffuse, large cell lymphoma of B cell, kappa phenotype and four patients immunosuppressive state before lymphoma.

Modulation of allogeneic immune responses by filgrastim (recombinant human granulocyte colony-stimulating factor) in bone marrow transplantation

We examined whether the use of G-CSF would affect the outcome of allogeneic marrow transplantation in humans and mice. Retrospective analysis of 24 patients who had received allogeneic marrow grafts from HLA-identical siblings revealed that the incidence of chronic but not acute graft-versus-host disease (GVHD) was lower in the patients receiving G-CSF than in those not given G-CSF (18% vs. 80%, P = 0.02). There was a difference in serum TNF-alpha levels during the first 3 months after transplant between these two groups. Four out of the ten patients who were not given G-CSF showed elevated serum TNF-alpha levels, whereas there was only one patients with an increased TNF-alpha level among eleven patients who were given G-CSF. With the use of murine acute and chronic GVHD models, we also observed that administration of G-CSF improved the survival of minor GVHD, but not major GVHD, mice. Taken together, these findings suggest that G-CSF down-regulates allogeneic immune responses and is active in modulating alloreactivity in vivo.

Sympathetic tone assessed by washout of iodine 125-labeled metaiodobenzylguanidine from the murine left ventricle--influence of immobilization stress and inhibition of the renin-angiotensin system

BACKGROUND

Because it is not metabolized as is norepinephrine (NE), most of the metaiodobenzylguanidine (MIBG) taken up by the heart is considered to be lost subsequently by release concomitant with sympathetic stimulation. Therefore we examined whether the washout of MIBG is influenced by sympathetic tone, which we modulated by using immobilization stress or activation of the renin-angiotensin system (RAS).

METHODS AND RESULTS

In 175 male ddY mice, left ventricular radioactivity was counted 30 minutes or 4 hours after injection of 74 kBq (2 microCi) of iodine 125- or iodine 131-labeled MIBG (125I- or 131I-MIBG). The washout rates of MIBG were determined under immobilization stress or under sodium loading or restriction in combination with losartan (10 mg/kg) or cilazapril (1 mg/kg) pretreatment. Immobilization enhanced the washout of 125I-MIBG (80.9% vs 57.9% in the control animals); this was determined to be related to washout from the neuronal compartment, because the nonneuronal component assessed through desipramine pretreatment was not affected. Pretreatment with losartan or cilazapril decreased the facilitation of 125I-MIBG washout in sodium-restricted mice (40.9% and 33.7%, respectively, vs 43.5% in the control animals), but not in sodium-loaded mice.

CONCLUSIONS

Measurement of MIBG washout may be feasible for determining the changes in sympathetic tone caused by immobilization stress or activation of the RAS.

Autoantibodies against 70-kDa heat shock proteins (HSP70) in allogeneic bone marrow transplant recipients

We report that autoantibodies against the 70-kDa heat shock protein family (HSP70) were detected in allogeneic bone marrow transplant recipients. Antibodies to HSP70 family proteins were detected in three out of 14 recipients of an allogeneic marrow graft but in none of the seven patients receiving autologous peripheral blood stem cell transplant (PBSCT). Immunoblotting analysis combined with two-dimensional SDS-PAGE revealed that these patients had antibodies to a constitutive 73-kDa/pI 5.5 heat shock protein (HSP73) and to a stress-inducible 72-kDa/pI 5.6 protein (HSP72). This is the first report, to our knowledge, describing the presence of autoantibody against HSP73 in allogeneic marrow transplant recipients. Our results may provide additional insight into the etiology and the pathophysiology of allogeneic transplant-related disorders.

Effects of a fixed point on postural readjustments caused by a moving visual scene

This study examined how postural readjustments caused by a moving scene can be affected by placing a fixed point (FP) onto the moving scene. Thirty-two healthy subjects participated in this study. Each subject maintained Romberg's position on a platform while vertical optokinetic stimulation (VOKS) was presented. A random dot pattern moving in a downward direction was projected on a large hemispherical screen placed in front of the subject. The magnitude of vection and forward displacement from the center of foot pressure (CFP) caused by VOKS were compared under two conditions: with and without FP. With FP, the magnitude of vection increased towards slow VOKS velocity, while forward displacement of CFP decreased significantly. These results indicate that an FP placed in a moving pattern may contribute to stabilizing postural orientations.

Modulation of left ventricular iodine-125-MIBG accumulation in cardiomyopathic Syrian hamsters using the renin-angiotensin system

Genetically inbred cardiomyopathic hamsters were examined to investigate the mechanism of reduced myocardial accumulation of metaiodobenzylguanidine (MIBG) in the cardiomyopathic heart.

METHODS

Bio 14.6 Syrian hamsters (hypertrophic stage: n = 15, early heart failure stage: n = 17) and control F1b strain golden hamsters (n = 36) were injected with 296 kBq of [125I] MIBG and killed 30 min or 4 hr later. Thirty-three of these hamsters were pretreated with 10 mg/kg of desipramine to determine non-neuronal MIBG accumulation. To evaluate the nonexocytotic MIBG release from nerve endings, desipramine was administered to four Bio 14.6 hamsters 15 min after [125I]MIBG injection. To determine the role of the activated renin-angiotensin system (RAS) in MIBG washout from sympathetic nerve terminals in cardiomyopathy at early heart failure stage, 10 mg/kg/day cilazapril, an angiotensin-converting enzyme inhibitor, was given orally to 7 controls and 16 cardiomyopathic hamsters for 16 wk.

RESULTS

In the absence of desipramine pretreatment, left ventricular [125I]MIBG accumulation 4 hr after injection was 0.376% +/- 0.015 %kg dose/g (mean +/- s.e.m.) in the hypertrophic hamsters (versus 0.418 +/- 0.019 in controls of the same age; ns), and 0.195 +/- 0.025 in early heart failure hamsters. Treatment with cilazapril partially restored MIBG accumulation in the Bio 14.6 hamsters but did not affect the controls.

CONCLUSION

Decreased [125I]MIBG accumulation in cardiomyopathic hamsters during the early heart failure stage is caused by neuronal release which is partially modulated by the activated RAS.

New variant t(9;11;14)(p22;q23;q24) suggests a translocation of 9p to 11q as the critical genetic event

We describe a patient with M5a (FAB classification) associated with a new type of variant translocation (9;11), namely t(9;11;14)(p22;q23;q24). The translocation of chromosome fragment from 9p to 11q is the common feature among the five variant translocations in the literature and our patient.

Usefulness of resting thallium-201 delayed imaging for detecting myocardial viability in patients with previous myocardial infarction

To test the feasibility of resting thallium-201 (201Tl) initial and delayed scintigraphy for detecting the area of viable myocardium, we performed single photon emission computed tomography (SPECT) in 57 patients with previous myocardial infarction (MI). All had received coronary arteriography (CAG) and left ventriculography (LVG). Initial and delayed myocardial imagings were carried out 10 min and 2 hours, respectively, after the injection of 201Tl at rest. Redistribution was judged by visual interpretation and/or the circumferential profile curve, and found in the infarcted or its adjacent area in 40 of the 57 cases (70.2%). A negative washout (net increase of 201Tl uptake in delayed image) was detected in 17 of these 40 cases. In 10 of the 57 patients, both exercise and rest-injected 201Tl myocardial images were obtained at exercise and rest, and compared visually. The areas of abnormal perfusion were smaller in the resting delayed images than those seen after exercise in 9 of the 10 cases, and were equal in one case. Thus, resting 201Tl delayed myocardial scintigraphy appears to reduce the underestimation of the size of the viable myocardium by the usual 201Tl images obtained after exercise or by single initial images obtained at rest in patients with previous MI.

Ph+ acute myelogenous leukemia with t(7;11)(p15;p15) and clonal evolution in relapse after bone marrow transplantation

A 20-year-old female with Ph+ acute myelogenous leukemia (M2) associated with t(7;11)(p15;p15) is reported. Bone marrow aspirates were hypercellular with leukemic cells including Auer rods. Chromosome analysis showed t(7;11) and the Ph chromosome. After complete remission, normal karyotype was restored. Normal male karyotypic cells replaced the bone marrow following allogeneic bone marrow transplantation from her brother. On day 358, cytogenetic study at relapse revealed 14q+ as an additional change and clearly showed that the abnormal clone was derived from the patient, because metaphases with XX were all of abnormal karyotype and those with XY were normal.

[A retrospective comparison study of patients old and young with non-Hodgkin's lymphoma]

One hundred patients with diffuse non-Hodgkin's lymphoma were treated with combination chemotherapy including adriamycin. Seventy-one patients were under age 70 and 29 were 70 years or older. The clinical characteristics of the two groups were similar, except that the patients showed elevated serum BUN were in the elderly group. The complete remission rate in the elderly patients (66%) was slightly lower than that in the younger patients (75%) (p = NS). The average length of survival in the elderly patients was significantly shorter than in the younger patients (p less than 0.05) (projected 5-year survival: 28 +/- 11% vs 52 +/- 7%). The duration of remission for all patients in the elderly patients did not differ from that in the younger patients (projected 2-year survival: 40 +/- 10% vs 45 +/- 6%). Death during the induction chemotherapy from causes other than lymphoma occurred in 14% of patients over 70-year-old and in one percent of younger patients. At relapse, the response rate was significantly lower in the elderly patients than in the younger patients (CR+PR: 28% vs 78%, p = 0.03). To prevent toxic death in remission induction therapy, drug dose elderly patients should be attenuated according to their general conditions and performance status.

[Clinical significance of immunophenotype in diffuse non-Hodgkin's lymphoma: with special emphasis on the clinical characteristics of T-cell lymphoma]

The clinical significance of immunophenotyping of the non-Hodgkin's lymphomas (NHL) is still controversial. Therefore, we evaluated the prognostic significance of T- and B-cell phenotype in 102 patients having diffuse non-Hodgkin's lymphoma who had been treated in a majority with Adriamycin-containing regimens. The significant differences in pretreatment clinical variables between the two patient groups were the higher frequency of markedly elevated LDH (greater than or equal to X 2 normal) and the lower frequency of decreased cholesterol level in B-NHL (p less than 0.05). Patients with B-NHL had a higher complete remission (CR) rate (77% vs 59%: p = NS), a significantly better overall survival (62% vs 34% at 3-years: p less than 0.05) and longer duration of remission for all patients (50% vs 27% at 3-years: p less than 0.05). Among forty-five patients with stages III and IV disease of nodal origin (excluding those with diffuse small cleaved histology), the B-cell group was associated with a better prognosis; a higher CR rate (68% vs 41%: p = NS) and a longer duration of remission for all patients (44% vs 12% at 2-years: p less than 0.05). Furthermore, for patients with T-cell phenotype, the primary site was the only prognostic factor; the patients whose disease originated from Waldeyer's ring, nasal cavity, and paranasal sinuses, achieved a better CR rate (92% vs 40%: p less than 0.05) and a longer duration of remission for all patients (48% vs 15% at 2-years: p less than 0.05). We conclude that advanced T-cell lymphoma of nodal origin is a subgroup of patients with very poor prognosis if treated with less intensive chemotherapeutic regimens.