Detection of impaired fatty acid metabolism and dyskinesis in hypertrophic cardiomyopathy with iodine-123-BMIPP

Metabolic imaging using 123I-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) and Fourier phase analysis of gated blood-pool data were performed in a 60-yr-old woman with idiopathic hypertrophic cardiomyopathy. Dyskinetic wall motion was identified as a markedly delayed phase angle in the left ventricular apex, which was well perfused but highly hypertrophied like other ventricular segments. Fatty acid imaging, however, clearly demonstrated highly reduced activities in the apex, although there were no abnormalities in regional systolic function or in 201TI uptake in other hypertrophied regions. Contrast left ventriculography revealed a midventricular collapse of the left ventricle at end-systole due to markedly hypertrophied ventricular walls and dyskinesis at the apex. Thus, dyskinetic wall motion in the apex closely correlated not only with cardiac hypertrophy but also with impaired fatty acid uptake. These findings were unrelated to the myocardial perfusion state per se. Fatty acid imaging using BMIPP may contribute to the detection of myocyte degeneration not visible using conventional imaging modalities. It may also provide etiological information on regional dysfunction in hypertrophic cardiomyopathy.

GABAB-ergic stimulation in hypothalamic pressor area induces larger sympathetic and cardiovascular depression in spontaneously hypertensive rats

To determine whether central GABA (gamma-aminobutyric acid) B receptor stimulation would affect the sympathetic and cardiovascular activities, baclofen (a GABAB receptor agonist) was injected into lateral cerebral ventricles (intracerebroventricularly, ICV) in urethane-anesthetized normotensive rats. Intracerebroventricular injections of GABAA agonist (muscimol, 1 microgram) consistently decreased blood pressure and heart rate. In contrast ICV injections of baclofen (2 micrograms) increased blood pressure (BP) and heart rate with initial transient cardiovascular depression, and these effects of baclofen were abolished by ICV pretreatment with GABAB antagonist (saclofen, 100 micrograms). To determine whether the cardiovascular effects of ICV injections were elicited by activating GABA receptors in the hypothalamus, we injected baclofen or muscimol directly into various hypothalamic areas. Baclofen (100 and 800 ng) injected into the ventromedial hypothalamus (VMH) or posterior hypothalamus (PH) of normotensive rats produced dose-related decreases in sympathetic nerve activity, blood pressure, and heart rate. These effects of baclofen were larger in VMH injections than in PH injections. The depressor responses elicited by VMH injections of baclofen were abolished by intravenous pretreatment with alpha-blocker, but unaffected by parasympathetic blocker, further indicating that the depressor responses of baclofen (VMH) were not due to parasympathetic activation, but due to peripheral sympathetic depression. Muscimol (400 ng) and baclofen (800 ng) injected into VMH produced similar amplitude of sympathetic-depressant, depressor and bradycardic responses. In contrast, BP was increased by the same dose of baclofen injected into the hypothalamic depressor area (anterior hypothalamus, AH), but was unaffected by muscimol. Final experiments were performed to determine whether these sympathetic and cardiovascular effects to hypothalamic GABAB stimulations would be altered in hypertension. In spontaneously hypertensive rats (SHR), basal BP and heart rate were already higher than in normotensive controls (Wistar-Kyoto rat, WKY). Baclofen injected into VMH reduced sympathetic nerve activity, BP, and heart rate in both groups of rats, and these effects were significantly larger in SHR than in WKY. This enhanced depressor response induced by baclofen (VMH) in SHR persisted even after sinoaortic denervation, which indicates that the enhanced depressor response is not due to reduced peripheral baroreflex sensitivity in SHR. On the other hand, baclofen injected into AH increased BP and heart rate in both WKY and SHR, but the magnitude of these responses did not differ between two groups. In summary, GABA reduces sympathetic nerve activity, BP, and heart rate through both GABAA and B receptors in VMH. The GABAB system acts on the depressor area, AH, to further regulate the cardiovascular activities. In SHR, the GABAB-ergic system in VMH but not in AH is altered, and this might contribute to the development of hypertension.

[Successful removal of an infected pacemaker electrode, drifted into the right atrium, by using a lead removal kit]

A 65-year-old male was suffered complications from an infected pacemaker in the left subclavian region. The generator was removed and its electrode was cut at the vascular entry. A new system was implanted on the other side. Two months later, he suffered from persistent fever which required administration of antibiotics for 2 months. 7 months later, the cut end of the infected electrode was found to have drifted into the right atrium. Its removal was performed to prevent a potential exacerbation of the systemic infection. We were able to pick up an end of the electrode using a basket catheter which was inserted through the right internal jugular vein to extract it. The lead was then successfully removed using a lead removal kit.

Visualization of slow axonal transport in vivo

In axons, cytoskeletal constituents move by slow transport. However, it remains controversial whether axonal neurofilaments are dynamic structures in which only subunits are transported or whether filaments assemble in the proximal axon and are transported intact as polymers to the axon terminus. To investigate the form neurofilament proteins take during transport, neurons of transgenic mice lacking axonal neurofilaments were infected with a recombinant adenoviral vector encoding epitope-tagged neurofilament M. Confocal and electron microscopy revealed that the virally encoded neurofilament M was transported in unpolymerized form along axonal microtubules. Thus, neurofilament proteins are probably transported as subunits or small oligomers along microtubules, which are major routes for slow axonal transport.

Cloning and characterization of KAP3: a novel kinesin superfamily-associated protein of KIF3A/3B

We previously reported that KIF3A and KIF3B form a heterodimer that functions as a microtubule-based fast anterograde translocator of membranous organelles. We have also shown that this KIF3A/3B forms a complex with other associated polypeptides, named kinesin superfamily-associated protein 3 (KAP3). In the present study, we purified KAP3 protein by immunoprecipitation using anti-KIF3B antibody from mouse testis. Microsequencing was carried out, and we cloned the full-length KAP3 cDNA from a mouse brain cDNA library. Two isoforms of KAP3 exist [KAP3A (793 aa) and KAP3B (772 aa)], generated by alternative splicing in the carboxyl terminus region. Their amino acid sequences have no homology with those of any other known proteins, and prediction of their secondary structure indicated that almost the entire KAP3 molecule is alpha-helical. We produced recombinant KAP3 and KIF3A/3B using a baculovirus-Sf9 expression system. A reconstruction study in Sf9 cells revealed that KAP3 is a globular protein that binds to the tail domain of KIF3A/3B. The immunolocalization pattern of KAP3 was similar to that of KIF3A/3B in nerve cells. In addition, we found that KAP3 does not affect the motor activity of KIF3A/3B. KAP3 was associated with a membrane-bound form of KIF3A/3B in a fractional immunoprecipitation experiment, and since the KIF3 complex was found to bind to membranous organelles in an EM study, KAP3 may regulate membrane binding of the KIF3 complex.

Regional cardiac sympathetic nerve dysfunction and the diagnostic efficacy of metaiodobenzylguanidine tomography in stable coronary artery disease

The present study endeavors to correlate regional myocardial sympathetic nerve dysfunction with reversible and persistent perfusion abnormalities and depressed regional wall motion, and to determine the diagnostic efficacy of radio-iodinated metaiodobenzylguanidine (MIBG) tomography for detecting coronary artery disease. In 28 consecutive patients with stable coronary artery disease and 7 patients with atypical chest pain but no coronary stenosis, regional MIBG uptake was semiquantitatively evaluated in 13 left ventricular segments early (30 minutes) and late (4 hours) after injection. Regional MIBG uptake was reduced in 68 of 90 segments (76%) showing reversible perfusion abnormality and 72 of 81 segments (89%) showing persistent abnormality 4 hours after injection. Although the sensitivity and negative predictive values of late MIBG scanning for detecting myocardial perfusion abnormalities were relatively high (82% and 85%, respectively), the specificity, positive predictive value, and kappa value were low (63%, 57%, and 0.41, respectively). Right coronary lesions were detected by late MIBG scanning with a high sensitivity (85%) but a low specificity (41%). Conversely, the sensitivities for detecting lesions in the other 2 major left coronary arteries were low (55%). The overall diagnostic accuracy of late MIBG scanning was 66% and the positive and negative predictive values and kappa value were low; 60%, 70%, and 0.31, respectively. Similarly, regional sympathetic dysfunction was observed in 42 of 49 asynergic segments (86%) on late MIBG scans, of which 32 segments were viable and 10 nonviable; but the low specificity (73%) and positive predictive value (44%) reduced the kappa value (0.43). Thus, regional cardiac sympathetic innervation is impaired in ischemic, asynergic but noninfarcted myocardium as well as in myocardium which is infarcted or has a persistent perfusion abnormality. The diagnostic efficacy of MIBG tomography to detect coronary artery disease, however, is limited probably because of nonspecific reductions of MIBG uptake in the inferior and posterolateral regions.

[Natural killer cell lymphoma having a nodular shadow in the lung as an initial finding, developed to leukemia complicated with hemophagocytic syndrome at the time of relapse]

A 57-year-old female was admitted to Uji hospital for the further evaluation of nodular shadow on her right lung. During the period of admission, she developed cervical lymph node swelling. She was diagnosed as having malignant lymphoma (diffuse, small cleaved cell) by lymph node biopsy. She received combined chemotherapy and obtained partial remission for seven months until she developed fever and pancytopenia. Laboratory data showed increased number of large granular lymphocytes (LGLs) in blood. Bone marrow revealed increased number of LGLs with hemophagocytosis by macrophage. Surface marker analysis revealed LGLs were positive for CD2 CD16, and CD56 and negative for CD3, CD4, CD8, and CD20. T-cell receptor genes beta and gamma were in germ line configuration. Analysis of Epstein-Barr virus genome using termini probe indicated a monoclonal proliferation of LGLs. Reexamination of the biopsy specimen of lymph node revealed LGLs which was negative for CD3 and CD20. The patient was diagnosed as a leukemic phase of natural killer (NK) cell lymphoma complicated with hemophagocytic syndrome (HPS). Serum levels of interferon-gamma, macrophage colony-stimulating factor, granulocyte colony-stimulating factor, and interleukin-6 increased, which might be related to HPS.

Transgenic expression of L-gulono-gamma-lactone oxidase in medaka (Oryzias latipes), a teleost fish that lacks this enzyme necessary for L-ascorbic acid biosynthesis

Transfer of the gene for L-gulono-gamma-lactone oxidase, the missing enzyme in L-ascorbic acid biosynthesis in scurvy-prone animals, into medaka (Oryzias latipes) was successfully done. The expression plasmid pSVL-GLO, carrying rat liver L-gulono-gamma-lactone oxidase cDNA, was microinjected into the cytoplasm of fertilized eggs during the one-cell stage. Four male F0 fish having the transgene in their germ cells came to maturity, and F1 progeny derived from one of the F0 fish possessed L-gulono-gamma-lactone oxidase activity, indicating that the transgene was functionally expressed in the fish. Genomic Southern blot analysis demonstrated that the transgene existed in both chromosome-integrated and extrachromosomal forms.

The effect of combination splenectomy and low-dose FK506 therapy on graft survival after liver allograft transplantation in rats

The effect of splenectomy on allograft survival was investigated using orthotopic liver transplantation in a rat experimental model (ACI rat liver grafted to LEW rat). Control rats without any immunosuppressive treatment died, on average, 10.4 +/- 1.4 days after operation. Splenectomy alone somewhat prolonged the survival (13.4 +/- 2.0 days), and low-dose FK506 therapy moderately prolonged it (22.7 +/- 7 days). The graft survival period was significantly prolonged (39.7 +/- 6.3 days) when them two treatments were combined. The elevation of cytotoxic antiallograft antibodies was suppressed by splenectomy but not by low-dose FK506 therapy. The development of jaundice was moderately suppressed by FK506 but not by splenectomy. There was no difference between the pattern of body weight decline in either of them two groups and that in control rats. When these two treatments were combined at the same time, the elevation of cytotoxic antibodies, development of jaundice and decline of body weight were suppressed. These data indicate that B cells play an important role in the acute rejection of the rat liver allograft at least partially via production of cytotoxic antiallograft antibody. Splenectomy or other immunosuppressive methods affecting B cells can be a supplement for immunosuppression when using reduced-dose FK506.

[The perinatal risk factors and periventricular leukomalacia (PVL) in premature infants--relationship between fetal heart rate decelerations and PVL]

Periventricular leukomalacia (PVL) has recently been recognized as an important risk factor of neurological impairment in premature infants. We studied 29 PVL cases on perinatal risk factors comparing with a non-PVL matched control group retrospectively. Variable decelerations were more frequently observed with statistical significance in the PVL group in the intrapartum period. Then another study was conducted to evaluate the relationship between fetal heart rate (FHR) decelerations and cystic PVL prospectively. Since January 1993 through December 1994 we studied 209 low birth weight infants (31.1 +/- 3.2 weeks, 1,424 +/- 419 g) who had been subjected to intrapartum FHR monitoring and postnatal sonographic intracranial examinations sequentially every 7 days until discharge. Cystic PVL was detected in 6 of 209 cases (2.9%) and occurred only in infants who had revealed severe variable deceleration or prolonged deceleration (6/37, 16%) in intrapartum FHR monitoring. We conclude that in low birth weight infants intrapartum severe variable deceleration or prolonged deceleration might play a causal role in cystic PVL.

Blood pressure at health screening as a predictor of coronary heart disease in Kyoto

AIM

Most epidemiologic studies that have evaluated coronary risk factors have measured either mortality or morbidity of coronary artery disease (CAD) as endpoints. However, earlier detection and elimination of coronary risk factors are crucial. We therefore performed Master's double (i.e. 1.5 min x 2 = 3 min) two-step exercise electrocardiograph (ECG) test in apparently healthy asymptomatic subjects (men, n = 2274; women, n = 959) to elucidate the risk factors for early-stage CAD or silent myocardial ischemia.

METHODS

We examined the possible association of blood pressure at health screening and other suspected risk factors with exercise ECG test performance. The ischemic ECG response was determined by (1) > or = 0.5 mm horizontal or sagging S-T segment depression, (2) > or = 2.0 mm J-shaped S-T segment depression, or (3) T inversion in post-exercise ECG.

RESULTS

We found that 4.7% of men and 10.6% of women exhibited ischemic responses. Among males, the ischemic responders to the exercise ECG test had higher systolic and diastolic blood pressure. In addition, the male ischemic responders were older, had a higher obesity index, higher serum cholesterol, triglyceride, low-density lipoprotein (LDL)-cholesterol, protein, glucose, and uric acid levels, and a lower serum potassium level than normal responders. In contrast, the female ischemic responders to the exercise ECG test had higher systolic pressure, and higher serum cholesterol, LDL-cholesterol, and protein levels than normal responders. Mean blood pressure was correlated positively with most of the other coronary risk factors, and mild hypertensives and hypertensives had abnormal lipid, glucose, and uric acid levels in both sexes. A comparison of risk factors by age group revealed that only younger and middle-aged ischemic responders had higher blood pressure, serum cholesterol, and glucose levels than normal responders of both sexes, and that in older subjects all the differences between normal and ischemic responders became insignificant.

CONCLUSIONS

Elevated blood pressure at health screening, together with abnormal lipid and glucose metabolism, might be risk factors predicting early-stage or silent CAD. The elimination of these risk factors in younger men and women seems to be important.

Prognosis of hypertrophic cardiomyopathy: assessment by 123I-BMIPP (beta-methyl-p-(123I)iodophenyl pentadecanoic acid) myocardial single photon emission computed tomography

123I-BMIPP (beta-methyl-iodophenyl pentadecanoic acid) has shown unique properties for potential use in assessing myocardial metabolism. Previous basic and clinical studies demonstrated that the disturbances of myocardial metabolism precede the occurrence of myocardial perfusion abnormalities by using 201Tl in hypertrophic myocardium. The present study was therefore undertaken to determine whether or not 123I-BMIPP myocardial SPECT is useful in predicting the prognosis of hypertrophic cardiomyopathy (HCM) in 65 patients in 6 facilities. There were 33 patients with non-obstructive HCM, 12 with obstructive HCM, 12 with apical HCM and 8 with dilated-phase HCM. Fasted patients at rest received an intravenous injection of 111 MBq of 123I-BMIPP. Twenty to thirty minutes later, myocardial SPECT was carried out. The BMIPP severity score (BMIPP SS) was evaluated semiquantitatively by using representative short axial SPECT images. We followed up the incidence of cardiac events for a mean period of 3.0 +/- 0.6 years. Cardiac events occurred in 13 patients. Of these, 11 developed heart failure and 6 died (4 from heart failure and 2 from sudden death). The BMIPP SS in the dilated-phase HCM was significantly lower than that for the nonsurvivors. The BMIPP SS was particularly high in patients with fatal heart failure. Furthermore, there was a close negative correlation between the BMIPP SS and percent fractional shortening measured by echocardiography (r = -0.49). Finally, the mortality over the three years increased according to the extent of the BMIPP SS. In conclusion, these results indicate that BMIPP SS is useful in evaluating the severity of HCM. We conclude that 123I-BMIPP is a valuable metabolic tracer in predicting the outcome of HCM.

Postischemic functional recovery and BMIPP uptake after primary percutaneous transluminal coronary angioplasty in acute myocardial infarction

To correlate asynergic wall motion after primary percutaneous transluminal coronary angioplasty with myocardial perfusion and fatty acid metabolism, quantitative tomographies using thallium and radioiodinated 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) were performed during the acute and recovery stages in 56 consecutive patients with acute myocardial infarction, of whom 32 underwent primary percutaneous transluminal coronary angioplasty (group A) and 24 were conservatively treated (group B); 44 patients (79%) had 1-vessel disease. Reduced myocardial uptakes of thallium and BMIPP and regional wall motion were quantified with a bull's eye technique and a centerline method using contrast left ventriculography, respectively. BMIPP activity was significantly lower than that of thallium at an acute stage in both groups. Abnormal BMIPP activities and the difference in thallium and BMIPP abnormalities (perfusion metabolism mismatch) at an acute stage decreased significantly during follow-up in group A (111 +/- 13 to 99 +/- 12 and 30 +/- 10 to 15 +/- 10, respectively), and not in group B (129 +/- 31 vs 118 +/- 29 and 29 +/- 13 vs 30 +/- 10, respectively). Improvement in regional wall motion abnormality correlated closely with the improved uptakes of thallium and BMIPP (y = 0.64x + 26.4, r = 0.56, p < 0.05; y = 1.1x + 11.1, r = 0.81, p < 0.001; respectively). The mismatched uptake of both tracers at an acute stage was significantly related to recovery from asynergic wall motion during follow-up in group A (y = 0.45x + 13.9, r = 0.65, p < 0.005). In conclusion, despite restored myocardial perfusion by primary coronary angioplasty, BMIPP uptake is impaired in salvaged myocardium at an acute stage of infarction. However, the degree and improvement of perfusion metabolism mismatch in acute myocardial infarction may reflect subsequent recovery from postischemic wall motion abnormality in metabolically impaired but viable myocardium after coronary reperfusion.

mRNA expression of KIF1A, KIF1B, KIF2, KIF3A, KIF3B, KIF4, KIF5, and cytoplasmic dynein during axonal regeneration

Mouse brain expresses multiple kinesin superfamily proteins (KIFs), which are involved in vesicle transport. The expression of KIFs is developmentally regulated, and both the mRNA and proteins of KIF2 and KIF4 are expressed abundantly in the juvenile brain. To elucidate the role of individual kinesin superfamily motor proteins during regenerative outgrowth of axons, we examined the mRNA expression of KIF1A, KIF1B, KIF2, KIF3A, KIF3B, KIF4, and KIF5 in adult mouse dorsal root ganglion cells after sciatic nerve crush. Seven to fourteen days after the nerve crush, the mRNA expression pattern of neurofilament and beta-tubulin isotypes suggested that the regenerative outgrowth of axons was active. At these stages, levels of mRNA for KIF1A, KIF1B, KIF2, KIF3A, KIF3B, KIF4, and KIF5 were 50.80% of control. The levels of mRNA for KIF4, which are detected in juvenile brain but not in the adult, were under the detection limit in both control and regenerating dorsal root ganglion cells. Because mRNA of neither KIF2 nor KIF4 increased significantly, the results suggest that the gene expression of KIFs during regeneration does not recapitulate the embryonic development and support the hypothesis that different series of events take place during the regenerative and embryonic outgrowths of axons. In contrast, mRNA for cytoplasmic dynein was slightly increased, up to 140%. This is consistent with the hypothesis that retrograde transport plays critical roles in regeneration such as the transport of neurotrophic factors.

Effects of gamma-linolenic and eicosapentaenoic acids on blood pressure in SHR

1. The present study was performed to determine whether chronic treatments with gamma linolenic acid (n-6, GLA) or eicosapentaenoic acid (n-3, EPA) would alter serum and red blood cell (RBC) unsaturated fatty acid composition, and to determine whether these treatments would affect blood pressure (BP), serum lipid metabolism and the development of atherosclerosis in spontaneously hypertensive rats (SHR). 2. To compare the effects on atherosclerosis, some SHR were denuded of aortic endothelium so that the development of atherosclerosis would be accelerated. Olive oil (control), GLA or EPA (low dose: 5 mg/day per rat, high dose: 50 mg/day per kg, respectively) was administered intraperitoneally for 6 weeks in SHR. 3. GLA treatments increased GLA and its metabolite, dihomo-GLA, levels in serum but not in RBC, while EPA treatments increased EPA level both in serum and in RBC. 4. The BP of control SHR was further elevated. EPA significantly reduced this elevation of systolic, mean and diastolic pressure within the first week and thereafter, whereas GLA did not affect BP elevation. Neither heart rate or bodyweight gain was affected by these treatments. 5. Serum total cholesterol (TC), triglyceride (TG), and glucose (G) levels and the development of atherosclerosis were unaffected by either GLA or EPA treatment. 6. In summary, chronic EPA but not GLA treatment slightly reduced BP elevation in SHR. Although chronic GLA or EPA treatment increased the respective serum level, these treatments unaltered serum TC, TG and G levels, and could not prevent the development of aortic atherosclerosis in SHR.

Differences in the characterization of the Ca2+ current in ventricular myocytes between spontaneously hypertensive rats and normotensive rats

1. The slow inward Ca2+ current elicited at the membrane potential -30 mV in SHR and normotensive Wistar rats (WR) with voltage-clamp recording was examined for this study. 2. The maximal Ca2+ current of WR in the current-voltage relationship showed the unified membrane potential of +10 mV and the amplitude was -1.2 +/- 0.2 pA. In the case of SHR, however, the maximal Ca2+ current showed a lower and variable membrane potential between 0 and -20 mV. The amplitudes were -1.7 +/- 0.9 pA at 0 mV, -2.1 +/- 0.8 pA at -10 mV and -4.4 +/- 0.3 pA at -20 mV. 3. From the cell-attached patch-clamp recording, the conductance of unitary Ca2+ current and the slope value were the same in SHR and in WR. From the open-time histogram of the Ca2+ channel, the open state probability in SHR increased and the time constant from the exponential curve became slightly extended in SHR. 4. L-isoproterenol at 10(-6) mol/L increased the Ca2+ current in SHR and WR. The increased ratio of Ca2+ current by l-isoproterenol was smaller in SHR than that in WR. 5. The aspect of 1-4 suggests that the increase in Ca2+ current in SHR obtained by the voltage-clamp was explained partly by the increase of open-state probability of unitary Ca2+ channel activity, and that a possibility of Ca2+ channel being activated by phosphorylation through cAMP did not eventuate.

Role of nitric oxide in impaired coronary circulation and improvement by angiotensin II receptor antagonist in spontaneously hypertensive rats

1. To determine whether coronary flow regulation by nitric oxide (NO) is impaired in the hypertensive heart (HTH), coronary perfusion was measured in isolated rat hearts using NO synthesis inhibitor L-NG-monomethyl arginine (L-NMMA) in Wistar-Kyoto (WKY) rat and spontaneously hypertensive rat (SHR) with and without chronic Nomega-nitro-L-arginine-methylester (L-NAME) treatment. Moreover, the effect of angiotensin II receptor antagonist (AT1 receptor antagonist) (TCV-116) on the impaired coronary circulation in HTH was examined. 2. Coronary flow (CF) was decreased in HTH accompanied with cardiac hypertrophy. The decreased response of CF to L-NMMA infusion was diminished in HTH. It is suggested that NO production was reduced in coronary vasculature in HTH. 3. In chronic L-NAME treated SHR, blood pressure and cardiac hypertrophy were accelerated. Although coronary flow resistance (CFR) was increased, the increased response of CFR to L-NMMA infusion was not altered. 4. The AT1 antagonist improved total minimal coronary flow resistance (MCFR) restoring CFR response in SHR, although it did not recover CFR response in chronic L-NAME treated SHR. 5. Taken together the findings suggest that NO production was exhausted in the coronary artery even in the developing stage of hypertension and this exhaustion could contribute to the impairment of coronary circulation of HTH.

[Induction and release of manganese superoxide dismutase caused by tumor necrosis factor-alpha from mitochondria in human umbilical vein endothelial cells]

The effects of tumor necrosis factor-alpha (TNF-alpha) on cultured human umbilical vein endothelial cells (EC) and five cancer cell lines, A549, ME180, A2780, KURAMOCHI, and Hela, were compared. While A549, A2780, KURAMOCHI, and Hela cells were fairly resistant to the cytolytic effects of TNF-alpha, ME180 cells were sensitive. EC were also less sensitive to TNF-alpha than ME180 cells as judged by the viability of individual cells and by the release of lactate dehydrogenase (LDH) into the medium. Manganese superoxide dismutase (Mn-SOD) was markedly induced by these cytokines in EC and in A549 cells but not in ME180 cells. The levels of Mn-SOD in the conditioned medium of EC were dramatically increased after stimulation with cytokines, whereas those in ME180 and A549 cells were relatively low. The amount of Mn-SOD released appears to be comparable to that from cells lysed by other means. Immunoblot analysis of Mn-SOD in the medium showed that the molecular mass of the immunoreactive protein was the same as mitochondrial Mn-SOD, indicating that no proteolysis had occurred. These data suggest that in vivo the TNF-alpha produced by cancer cells may induce Mn-SOD in vascular endothelial cells, resulting in release of a relatively large amount of this protein into the serum.

Hypothalamic and medullary GABAA and GABAB-ergic systems differently regulate sympathetic and cardiovascular systems

1. To determine whether hypothalamic and medullary GABA (gamma-aminobutyric acid)B stimulation would affect the sympathetic and cardiovascular activities, and to determine whether these effects would be altered in hypertension, baclofen (a GABAB agonist) was injected into a hypothalamic pressor area (ventromedial hypothalamus, VMH), a depressor area (anterior hypothalamus, AH), or a nucleus tractus solitarius (NTS) in normotensive and spontaneously hypertensive rats (SHR). 2. Intracerebroventricular (ICV) injections of a GABAA agonist (muscimol, 1 mu g) decreased blood pressure (BP) and heart rate (HR). ICV injections of baclofen (2 mu g) elicited biphasic depressor and pressor effects, and these effects were abolished by a pretreatment with saclofen (GABAB antagonist, 100 mu g, icv). 3. Muscimol (400 ng) and baclofen (800 ng) injected into VMH decreased sympathetic nerve activity (SNA), BP and HR to almost similar levels, while saclofen injected into VMH increased HR without affecting BP levels. 4. The same dose of baclofen injected into AH increased BP, but muscimol (AH) did not alter BP. 5. Both muscimol and baclofen injected into NTS increased BP, but its magnitude was larger in baclofen injections. 6. Depressor and sympatho-inhibitory effects of baclofen (VMH) in SHR were larger than those in normotensive Wistar-Kyoto (WKY) rats, while pressor responses elicited by baclofen (AH) did not differ between SHR and WKY. 7. In summary, GABA reduces SNA, BP and HR through both GABAA and GABAB receptors in VMH. In addition, the GABAB system acts on AH and NTS to further regulate the cardiovascular activities. In SHR, GABAB-ergic dysfunction in VMH but not in AH might contribute to the development of hypertension.

Role of baroreflex and central alpha2-adrenergic receptor systems in the diurnal variation of blood pressure and heart rate in normotensive and hypertensive rats

1. To elucidate whether baroreflex could contribute to manifest the diurnal blood pressure variations (DBPV) in normotension and hypertension, DBPV were recorded continuously via a femoral artery in awake normotensive (NT) rats and spontaneously hypertensive rats (SHR) with and without sinoaortic denervation (SAD). To determine the role of central alpha2-adrenergic receptor system in DBPV in hypertension, guanabentz (0.5-1.0 mu g/kg per min) was infused in SHR. 2. There were no differences in mean arterial pressure (MAP) variability (SD) of MAP of 24 h (MAP -- SD/MAP) and SD of 24 h heart rate (HR -- SD/HR) between SHR and NT. SAD did not elevate MAP and HR in both SHR and NT. 3. However, in SAD rats, MAP -- SD/MAP was significantly greater than those in sham-operated rats in both SHR and NT, while MAP -- SD/MAP and HR -- SD/HR did not show any difference between the two groups even after SAD. On the other hand, SAD did not augment HR -- SD/HR in either strain. 4. During guanabentz infusion, MAP was significantly lowered in sham-operated and SAD -- SHR. Moreover, MAP -- SD/MAP was significantly reduced in sham-operated, but it was not in SAD -- SHR. 5. These findings suggest that baroreflex could suppress tonically the diurnal change of blood pressure in NT and SHR. The regulation of diurnal blood pressure by baroreflex via a central alpha-adrenergic receptor system may be altered in SHR.

Point mutation of adenosine triphosphate-binding motif generated rigor kinesin that selectively blocks anterograde lysosome membrane transport

In the study of motor proteins, the molecular mechanism of mechanochemical coupling, as well as the cellular role of these proteins, is an important issue. To assess these questions we introduced cDNA of wild-type and site-directed mutant kinesin heavy chains into fibroblasts, and analyzed the behavior of the recombinant proteins and the mechanisms involved in organelle transports. Overexpression of wild-type kinesin significantly promoted elongation of cellular processes. Wild-type kinesin accumulated at the tips of the long processes, whereas the kinesin mutants, which contained either a T93N- or T93I mutation in the ATP-binding motif, tightly bound to microtubules in the center of the cells. These mutant kinesins could bind to microtubules in vitro, but could not dissociate from them even in the presence of ATP, and did not support microtubule motility in vitro, thereby indicating rigor-type mutations. Retrograde transport from the Golgi apparatus to the endoplasmic reticulum, as well as lysosome dispersion, was shown to be a microtubule-dependent, plus-end-directed movement. The latter was selectively blocked in the rigor-mutant cells, although the microtubule minus-end-directed motion of lysosomes was not affected. We found the point mutations that make kinesin motor in strong binding state with microtubules in vitro and showed that this mutant causes a dominant effect that selectively blocks anterograde lysosome membrane transports in vivo.

Splenic metastasis from lung cancer

Splenic metastasis from lung cancer is a rare clinical event, most often diagnosed at the time of autopsy. We report 2 cases of splenic metastasis with a primary lung cancer. The first case was a 76-year-old man presenting with a recurrent solitary splenic metastasis 14 months after surgical removal of a squamous cell carcinoma of the lung. The second patient was a 72-year-old woman who had a poorly differentiated carcinoma of the lung and multiple abdominal metastasis. We also investigated 267 autopsy cases of lung cancer from 1975 to 1992. Histologically, there were 73 cases of squamous cell carcinoma, 123 adenocarcinoma, 29 large cell carcinoma, 36 small cell carcinoma, and 7 other miscellaneous tumours. The number of splenic metastasis from lung cancer in these cases was 15 (5.6%). Splenic metastasis from a primary cancer of the left lung was more frequent than that from the right lung. Nine of 15 splenic metastases were smaller than 1 cm in size. Splenic metastasis was associated with liver and pancreas metastasis. All 15 autopsy cases with splenic metastasis from lung cancer had other abdominal organ metastasis. Our analysis indicates that a solitary splenic metastasis is rare. Selection of a suitable therapeutic approach is important.

Altered cardiovascular responses to purinergic A2 stimulation in the nucleus tractus solitarius of spontaneously hypertensive rats

OBJECTIVE

To investigate the cardiovascular effects of adenosine A2 receptor stimulation in the nucleus tractus solitarius and whether these effects are altered in hypertension.

DESIGN AND METHODS

Ten- or 11-week-old spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats were anaesthetized with urethane. Adenosine (100 ng) or adenosine A2 agonist (2-octynyladenosine, 5 ng) were micro-injected (50 nl) into the nucleus tractus solitarius. Blood pressure and heart rate were measured from a femoral artery. Sympathetic nerve activity was recorded from the abdominal splanchnic nerve.

RESULTS

Blood pressure, heart rate and sympathetic nerve activity were consistently decreased after the micro-injection of adenosine into normotensive rats. Changes from the baseline in blood pressure, heart rate and sympathetic nerve activity were significantly smaller in SHR than in WKY rats (blood pressure: SHR -5.6 +/- 2.1% versus WKY rats -20.0 +/- 2.1%; heart rate: SHR -5.4 +/- 0.88% versus WKY rats -9.2 +/- 2.3%; sympathetic nerve activity: SHR -5.5 +/- 1.1% versus WKY rats -21 +/- 2.8%). Micro-injection of an A2 agonist into the nucleus tractus solitarius also decreased blood pressure and heart rate, and those responses were not inhibited by pretreatment with an adenosine A1-specific antagonist. The response induced by micro-injection of A2 agonist into the nucleus tractus solitarius was significantly smaller in SHR than in WKY rats, whereas the changes in heart rate did not differ statistically (blood pressure: -23.4 +/- 4.7% versus -10.8 +/- 2.1%; heart rate: -12.1 +/- 1.2% versus -13.6 +/- 2.1%).

CONCLUSION

The present results suggest that stimulation of adenosine A2 receptors in the nucleus tractus solitarius decreases both blood pressure and inhibitory sympathetic nerve activity and that those inhibitory responses to adenosine in the nucleus tractus solitarius are deranged in SHR.

[Clinical implications of mismatched uptakes of beta-methyl fatty acid analogue and thallium in infarcted myocardium: correlations with coronary stenosis and regional wall motion abnormality]

Myocardial perfusion and fatty acid metabolism were assessed by using myocardial single-photon emission computed tomography with thallium and beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) during acute and/or late stages of myocardial infarction in 157 infarcted segments of 100 patients. The incidence of reduced thallium perfusion relative to BMIPP uptake ("T-type" mismatch) was significantly (p < 0.05) lower (9%) compared to that of reduced BMIPP uptake relative to thallium perfusion ("B-type" mismatch) (59%) or non-mismatched segment (32%). In an anteroseptal region, B-type dissociation had a significantly higher incidence compared to no or T-type mismatch; 68% vs. 27% vs. 5%, respectively, whereas the incidence of T-type uptake was relatively high in inferior and posterolateral regions; 13%, 11%, respectively. Severe coronary stenosis was observed in 76% of B-type segments and 72% of non-mismatched segments but in only 43% of T-type segments. The incidence of regional wall motion abnormality was significantly lower (46%) in the T-type mismatch segments when compared to the B-type (91%) or non-mismatched segments (96%). In conclusion, myocardial fatty acid metabolism was more markedly impaired compared to an involved coronary perfusion, resulting in the mismatch of perfusion and fatty acid metabolism. Coronary stenosis and regional wall motion abnormality are more closely related to "B-type" mismatch but not necessarily to "T-type" dissociation, probably because of attenuation artifacts in inferior and posterolateral regions in thallium scan.