Augmented response of endothelin-A and endothelin-B receptor stimulation in coronary arteries of hypertensive hearts

To determine whether the vasoconstrictor response to endothelin-1 (ET-1) is altered in coronary vessels of hypertensive hearts and the role of ETA and ETB receptors in these responses to ET-1, the vasoconstrictor response to ET-1 in coronary vessels was measured with or without ETA and ETB receptor antagonists. In isolated hearts of spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat, the coronary perfusion pressure was measured on a Langendorff apparatus with constant pressure (75 mm Hg). Coronary perfusion resistance (CPR) (mm Hg/ml/min/g) was calculated. ET-1 elicited dose-dependent increases of CPR in both normotensive and SHR rat hearts. However, the responses were significantly greater in SHR than those of WKY. Pretreatment with the ETA antagonist FR139317 and the ETB antagonist BQ788 inhibited CPR increases with ET-1 infusion. However, vasoconstrictor responses to ET-1 were still greater in SHR than in WKY after FR139317 or BQ788 infusion. These findings suggest that the augmented vasoconstrictor response of coronary artery to ET-1 is mediated by both ETA and ETB receptors. These changes may contribute to the impaired coronary circulation in hypertension.

Sequential percutaneous microwave coagulation therapy for liver tumor

BACKGROUND

Percutaneous microwave coagulation therapy (PMCT) is effective for small liver tumors. To enhance the radicality of PMCT, we developed a sequential coagulation technique.

METHODS

After inserting the first guide-needle under sonography, multiple needles were placed through a disk-type introducer that was devised to guide needle puncture at regular intervals, and microwaves were irradiated. Six patients, including 4 with hepatocellular carcinoma and 2 with liver metastasis, underwent this technique for tumors of 15 to 80 mm in diameter.

RESULTS

This technique can coagulate an area up to 60 mm in diameter in one session. Insertion of multiple needles, ranging from 2 to 11, was successful without complications. Three patients undergoing curative PMCT developed no tumor recurrence. The other 3 received incomplete PMCT due to the large size and location of the tumor.

CONCLUSIONS

This preliminary study indicates the efficacy of this technique to facilitate and secure PMCT in selected patients with liver tumors.

Visualization of the dynamics of synaptic vesicle and plasma membrane proteins in living axons

Newly synthesized membrane proteins are transported by fast axonal flow to their targets such as the plasma membrane and synaptic vesicles. However, their transporting vesicles have not yet been identified. We have successfully visualized the transporting vesicles of plasma membrane proteins, synaptic vesicle proteins, and the trans-Golgi network residual proteins in living axons at high resolution using laser scan microscopy of green fluorescent protein-tagged proteins after photobleaching. We found that all of these proteins are transported by tubulovesicular organelles of various sizes and shapes that circulate within axons from branch to branch and switch the direction of movement. These organelles are distinct from the endosomal compartments and constitute a new entity of membrane organelles that mediate the transport of newly synthesized proteins from the trans-Golgi network to the plasma membrane.

Identification of a new commonly deleted region within a 2-cM interval of chromosome 11p11 in breast cancers

Allelic loss has been observed on the short arm of chromosome 11 in a variety of human cancers. We have examined 184 breast cancers for allelic loss anywhere in chromosome 11p, using 15 well-spaced microsatellite markers. Allelic loss was observed in 86 cases (47%) and a new commonly deleted region 2-cM in length was identified at 11p11 between loci D11S986 and D11S1313, in addition to a 12-cM region of a common deletion at 11p15.5. A significant association was found between allelic loss on 11p15.5 and LOH on 11p11 and the loss of progesterone receptors.

Ischemic and non-ischemic myocyte damage and antimyosin monoclonal imaging

Antimyosin monoclonal antibody is a specific marker of impaired sarcolemmal integrity resulting not only from ischemia but also from non-ischemic myocardial injury, such as infection, inflammatory, or immunologic reactions, and alcohol or drug intoxication. In addition, antimyosin accumulation has been demonstrated in some forms of cardiomyopathy with unknown as well as known etiologies. Antimyosin positivity appears to indicate precisely the extent of myocardial necrosis and to reflect cardiac dysfunction in an acute stage of active myocardial damage caused by ischemia and inflammation. However, the correlation is not necessarily good in the chronic stages of the disease or in idiopathic cardiomyopathic hearts; in other words, cardiac antimyosin uptake can be detected even in myocardial tissue with a normal histologic appearance independent of the presence of inflammatory responses, myocyte necrosis, or functional or morphologic deterioration. Thus, antimyosin is useful not only for detecting and quantifying acute myocardial necrosis but also for specifically identifying ongoing or latently progressing myocardial degeneration and sarcolemmal disruption, which will certainly lead to myocardial necrosis. These characteristics may contribute to the early detection of myocardial damage and lead to the investigation of pathophysiologic mechanisms. Further progress in immunologic and radiolabeling techniques is necessary for better specificity and less antigenicity against humans in antimyosin monoclonal antibody imaging.

Blockade of angiotensin II receptors inhibits the increase in blood pressure induced by insulin

To elucidate whether hyperinsulinemia increases blood pressure by increasing sympathetic outflow via the activation of the central angiotensin system, insulin was infused into urethane-anesthetized rats intravenously (i.v.) or intracerebroventricularly (i.c.v.) under euglycemic conditions. Infusion (i.v.) of insulin elicited pressor effects in a dose-dependent manner (13, 20, and 40 mU/min). Although depressor responses to i.v. injections of hexamethonium were significantly greater in insulin-infused than in saline-infused rats, i.v. captopril and d(CH2)5Tyr(Me)-arginine vasopressin did not show any differences between the groups. Infusions (i.c.v.) of insulin (8 mU/10 microl) also induced cardiovascular acceleration and augmented the depressor response to i.v. hexamethonium in insulin-infused rats. The i.c.v. pretreatment with the angiotensin II antagonist losartan inhibited the pressor responses to both the i.c.v. and i.v. infusion of insulin. These results suggest that the increase in blood pressure induced by euglycemic hyperinsulinemia is elicited by sympathetic activation and that hyperinsulinemia stimulates the angiotensin system in the brain to increase sympathetic nerve activity.

The MAP kinase kinase kinase MLK2 co-localizes with activated JNK along microtubules and associates with kinesin superfamily motor KIF3

The MLK (mixed lineage) ser/thr kinases are most closely related to the MAP kinase kinase kinase family. In addition to a kinase domain, MLK1, MLK2 and MLK3 each contain an SH3 domain, a leucine zipper domain and a potential Rac/Cdc42 GTPase-binding (CRIB) motif. The C-terminal regions of the proteins are essentially unrelated. Using yeast two-hybrid analysis and in vitro dot-blots, we show that MLK2 and MLK3 interact with the activated (GTP-bound) forms of Rac and Cdc42, with a slight preference for Rac. Transfection of MLK2 into COS cells leads to strong and constitutive activation of the JNK (c-Jun N-terminal kinase) MAP kinase cascade, but also to activation of ERK (extracellular signal-regulated kinase) and p38. When expressed in fibroblasts, MLK2 co-localizes with active, dually phosphorylated JNK1/2 to punctate structures along microtubules. In an attempt to identify proteins that affect the activity and localization of MLK2, we have screened a yeast two-hybrid cDNA library. MLK2 and MLK3 interact with members of the KIF3 family of kinesin superfamily motor proteins and with KAP3A, the putative targeting component of KIF3 motor complexes, suggesting a potential link between stress activation and motor protein function.

A furanoid labdane diterpene from Potamogeton nodosus

A new furanoid diterpene, 15,16-epoxy-12-oxo-8(17), 13(16), 14-labdatrien-20,19-olide (1) was isolated from an ethanolic extract of Potamogeton nodosus. Its structure was elucidated by the usual spectroscopic methods, including 2D NMR techniques. Compound 1 was found to exhibit moderate inhibitory activity against a number of both Gram-positive and Gram-negative bacteria.

Unique association of pheochromocytoma with contralateral nonfunctioning adrenal cortical adenoma

A 57-year-old woman complaining of hypertensive attacks associated with headache and palpitation was admitted to our hospital for examination of bilateral adrenal tumors in 1985. After right pheochromocytoma was diagnosed, right adrenalectomy was performed. The left adrenal tumor was small; thus, the left adrenal tumor was preserved to avoid adrenal insufficiency, although left adrenal pheochromocytoma could not be denied. In 1995, she was referred to our clinic again because of recurrent headache and palpitation, and enlargement of the left adrenal tumor. Although pheochromocytoma was suspected again, the enlarged left adrenal turned out to be a nonfunctioning cortical adenoma. This case was interesting, not only because of difficulty in identifying the left adrenal tumor, but also because of the rare coexistence of a pheochromocytoma and a nonfunctioning adrenal cortical tumor.

Multiplex mutation screening of the BRCA1 gene in 1000 Japanese breast cancers

To detect BRCA1 mutations in Japanese breast cancer patients, we screened 1,000 unselected primary cancers for mutations in exon 11, which accounts for 61% of the entire BRCA1 coding sequence. Using a method based on multiplex single-strand conformational polymorphism (SSCP) analysis of multiple restriction fragments generated by restriction-enzyme digestion of amplified DNA, we identified eight mutations. All eight were germline mutations; four of them were non-sense mutations or small deletions resulting in premature stop codons, and the other four were missense mutations. The Japanese carriers of these mutant BRCA1 alleles had developed breast cancers at ages ranging from 45 to 62, five of them bilaterally.

Rheumatoid arthritis associated with renal amyloidosis and crescentic glomerulonephritis

A 43-year-old woman with rheumatoid arthritis (RA), renal amyloidosis and crescentic glomerulonephritis had severe abdominal pain, melena and progressive renal failure. Autopsy findings revealed vasculitis of small and middle size of vessels and there was a deposition of amyloid in the small intestines. Although there were no findings of vasculitis in the kidney, amyloid deposition was noticed and 70-80% of glomeruli showed a crescentic formation. No immunological abnormality was found in glomeruli. Although the immunological mechanisms of crescentic glomerulonephritis were not necessarily eliminated, amyloid deposition may play a role in crescent formation.

Correlation of Allelic Losses and Clinicopathological Factors in Primary Breast Cancers

Human breast cancers frequently show allelic loss or loss of heterozygosity (LOH) at apecific chromosomal regions. To understand the possible role of these genetic alterations in tumor development and progression, we examined LOH at loci on chromosomal arms 1p, 3p. 11p, 13q, 16q, 18q, and 22q in 140 to 246 cases of primary breast cancers and compared it with lymph node metastasis, histological type, tumor stage, estrogen receptor (ER) and progesterone receptor (PgR) status. LOH at 1p22-31 correlated with lymph node metastasis and a tumor size of greater than 2 cm. LOH at 13q12-14 and 18q21 were most frequently observed in tumors of the solid-tubular type. LOH at 1p34-36 was more frequent in tumors of the scirrhous and solid-tubular types than in other less aggressive histological types. Furthermore, a significant association was observed between LOH at 3p14-21, 11p11-15 and 13q12-14 and the absence of progesterone receptors. These results suggest that some clinical characteristics of breast cancers are determined by loss of tumor supperssor genes present at specific chromosomal regions.

Chronic angiotensin blockade with candesartan cilexetil in DOCA/salt hypertensive rats reduces cardiac hypertrophy and coronary resistance without affecting blood pressure

To determine whether angiotensin II participates in the pathogenesis of cardiac hypertrophy and impairs coronary circulation in DOCA/salt hypertension, DOCA hypertensive rats were treated with candesartan cilexetil for 8 wk. DOCA/salt hypertension was induced in Wistar rats by removing the right kidney and subcutaneously injecting deoxycorticosterone acetate once a week. Control rats were given subcutaneous injections of saline and maintained on a normal diet. After 4 wk of observation, the angiotensin II receptor antagonist candesartan cilexetil was administered by oral gavage for 8 wk to 14 rats. Systolic blood pressure was measured weekly with the tail-cuff method. After 12 wk, the rats were killed and prepared. The isolated hearts were perfused by a Langendorff apparatus at constant flow. Perfusion pressure was measured by a small-volume transducer, and perfusion flow was recorded by a drop counter. Development of hypertension was not prevented by candesartan cilexetil treatment, but development of cardiac hypertrophy was inhibited. Minimum coronary vascular resistance (MCVR) obtained upon infusing adenosine into the isolated hearts was significantly higher in DOCA/salt hypertensive rats than in sham-operated controls. The elevated MCVR in DOCA/salt hypertensive rats was decreased by the administration of candesartan cilexetil for 8 wk. Thus, candesartan cilexetil regressed cardiac hypertrophy and improved coronary vascular resistance without affecting high blood pressure. These findings suggest that angiotensin II plays an important role in the pathogenesis of cardiac hypertrophy in DOCA/salt hypertension and that cardiac hypertrophy increases coronary vascular resistance.

Sustained right ventricular dyskinesis complicated by right ventricular infarction

We encountered a 66-yr-old man with acute left inferior and right ventricular infarction. Tomographic radionuclide ventriculography and Fourier analysis clearly demonstrated reduced wall motion in the inferior walls of both ventricles and markedly delayed phase angles in the inferior right ventricular segment, indicating dyskinesis, which was confirmed by two-dimensional echocardiography and contrast right ventriculography. Four years later, right ventricular dyskinesis was still present and corresponded to a right ventricular perfusion defect on 99mTc-labeled tetrofosmin tomogram. Right ventricular imaging with tomographic radionuclide ventriculography with Fourier analysis and 99mTc-labeled myocardial tomography demonstrates that, even after improved global function and hemodynamics, right ventricular dyskinesis related to right ventricular perfusion defect can be sustained for several years. Thus, these imaging techniques may contribute to diagnosing right ventricular infarction and investigating the pathophysiology.

Appropriate hematocrit levels of erythropoietin supplementary therapy in end-stage renal failure complicated by coronary artery disease

OBJECTIVE

To investigate an appropriate hematocrit (Hct) for managing renal anemia complicated by angina pectoris at rest.

DESIGN

Nonrandomized, retrospective and prospective observational study.

SETTING

Sapporo Medical University Hospital, Sapporo, Japan.

PATIENTS

Thirty-two anemic patients (aged 62 +/- 10 years, range 40 to 78) with rest angina in end-stage renal failure.

INTERVENTIONS

Serial changes of exercise tolerance (estimated metabolic equivalents [METs] on stress electrocardiography produced by improvement of patients' Hct, using recombinant human erythropoietin (rHuEPO). Adverse effects, such as deteriorating systemic hypertension, were investigated with regard to the severity of coronary arteriographic findings (Leaman's score) and cardiac events within a six-month period.

MAIN RESULTS

Higher Hct was clearly correlated with better estimated METs: when Hct was less than 20%, MET was 1.4 +/- 0.5; with 20% < or = Hct < 25% 2.1 +/- 1.4; with 25% < or = Hct < 30% 3.1 +/- 1.6; and with 30% < or = Hct < 35% 4.9 +/- 1.1. Patients with cardiac events (elective balloon angioplasty [n = 5], bypass surgery [n = 1], myocardial infarction [n = 2] and hospital death from congestive heart failure [n = 3]) had advanced coronary lesions compared with patients without coronary events (Leaman's score 15.9 +/- 9.3 versus 7.3 +/- 4.4, respectively, P < 0.01) and lower exercise capacity at 25% < or = Ht < 30% (estimated METs 2.4 +/- 1.2 versus 3.9 +/- 1.9, respectively, P < 0.05). Moreover, there was an inverse linear correlation between estimated METs and Leaman's score only when Hct was over 25%. In prospectively examined subjects (n = 16), Hct 35% or greater without systemic hypertension was obtained in only seven (44%), and no additional effect on exercise tolerance was expected when Hct was 35% or greater.

CONCLUSIONS

Managing renal anemia with 30% < or = Hct < 35% with rHuEPO is considered an appropriate therapy in patients with end-stage renal failure complicated by rest angina.

[A family with facioscapulohumeral muscular dystrophy and hereditary long QT syndrome]

We describe a family with facioscapulohumeral muscular dystrophy (FSHD) and hereditary long QT syndrome (LQT) for three generations. The proband, a 50-year-old woman, had noticed difficulty in raising the upper extremities since the age of 40. At the age of 48, she was admitted to our hospital because of arrhythmia attack. She, her mother, and one of her three children were diagnosed as having LQT. These three individuals and the proband's two siblings were clinically diagnosed as having FSHD which was confirmed by genetic analysis using EcoR1. FSHD is an autosomal dominant disorder and the gene locus is mapped to chromosome 4q35-ter, but the gene has not been isolated. LQT is a group of disorders which cause syncope and sudden death from ventricular arrhythmia in an autosomal dominant fashion. Four loci for this syndrome (LQT1-4) have been known, and three of the genes have been shown to encode ion-channels. Genetic analysis of the proband failed to detect any of previously known mutations in the LQT1, LQT2, and LQT3 genes. The locus for LQT4 has been mapped to chromosome 4q25-7. There have so far been no report of FSHD associated with LQT. Although the pathogenesis is unclear, we speculate that these two diseases are linked each other on chromosome 4q.

Crossover trial of simvastatin versus pravastatin in patients with primary hypercholesterolemia

The effects of simvastatin and pravastatin administered alone at initial doses of 5 and 10 mg/day, respectively, on normalization of abnormal lipid metabolism in patients with hypercholesterolemia were evaluated by a crossover method. Patients whose serum levels of total cholesterol (TC) were > or = 220 mg/dl were randomly divided into two groups, and one of the groups (group S-P: 17 patients) was treated with simvastatin first and then with pravastatin whereas the other group (group P-S: 19 patients) was treated with pravastatin first and then with simvastatin. Simvastatin or pravastatin was replaced with the other drug after 8-week administration in each group. These drugs were administered for 8 weeks each. Simvastatin and pravastatin significantly reduced the following serum lipids as compared with the levels in the observation period: TC by 23.2 +/- 8.1% and 18.1 +/- 10.9%, triglyceride (TG) by 13.0 +/- 24.7% and 5.8 +/- 47.1%, and low-density lipoprotein cholesterol (LDL-C) by 31.3 +/- 10.1% and 23.1 +/- 14.3%, respectively. TC and LDL-C levels were significantly (p < 0.001) lower and decreased to significantly (p < 0.001) greater degrees after simvastatin treatment than after pravastatin treatment. TC was normalized in 77.8% of the patients (28 of 36) after simvastatin treatment and in 68.9% of the patients (23 of 36) after pravastatin treatment. LDL-C was normalized in 63.9% of the patients (23 of 36) after simvastatin treatment and in 44.4% of the patients (16 of 36) after pravastatin treatment. The percentage of patients whose LDL-C was normalized by simvastatin was significantly (p < 0.05) higher as compared with pravastatin. Results of this trial, which was conducted by a crossover method, show that the initial dose of simvastatin reduces serum cholesterol and LDL-C more potently than the initial dose of pravastatin in patients with hypercholesterolemia.

Neurovascular compression of the rostral ventrolateral medulla related to essential hypertension

The rostral ventrolateral medulla (RVLM) is thought to serve as a final common pathway for the integration of central cardiovascular information and to be important for the mediation of central pressor responses. An association between essential hypertension and neurovascular compression of the RVLM has been reported. To confirm this relationship and to quantitatively measure the distances between the RVLM and the neighboring arteries, we performed magnetic resonance imaging using a high-resolution 512x512 matrix and magnetic resonance angiography in 49 subjects (21 patients with essential hypertension, 10 patients with secondary hypertension, and 18 normotensive subjects). One patient with essential hypertension was excluded from the evaluations because of inadequate assessment due to poor images. Neurovascular compression of the RVLM was observed in 15 of 20 (75%) patients with essential hypertension. In contrast, neurovascular compression was observed in only 1 of 10 (10%) patients with secondary hypertension and only 2 of 18 (11%) normotensive subjects. The rate of observed neurovascular compression in the essential hypertension group was significantly higher than that in the secondary hypertension group and the normotensive group (P<.01 for both). The distances between the RVLM and the nearest arteries in the essential hypertension group were significantly shorter than those in the other groups (P<.05 for all). On the other hand, the distances between the surface of the medulla oblongata and the nearest arteries did not differ among these three groups. These results suggest that neurovascular compression of the RVLM, but not of the other regions of the medulla oblongata, is particularly related to essential hypertension.

Bruceine B, a potent inhibitor of leukocyte-endothelial cell adhesion

Leukocyte adhesion to vascular endothelial cells is an essential step in the development of inflammatory diseases. We have searched for inhibitors of leukocyte-endothelial cell adhesion that could be used as anti-inflammatory drugs and found that bruceine B (0.2 microgram/ml; 0.44 microM) inhibited human neutrophil or T cell adhesion to tumor necrosis factor-alpha (TNF) stimulated human umbilical vein endothelial cells (HUVEC). The inhibition of neutrophil adhesion to TNF-stimulated HUVEC by bruceine B was not derived from cytotoxic effects, as determined by measurement of the level of lactate dehydrogenase (LDH) activity in conditioned medium. The effect of bruceine B on neutrophil adhesion to HUVEC was not seen when the neutrophils were preincubated with bruceine B. However, inhibitory effects were evident when the HUVEC were preincubated with bruceine B. Bruceine B also inhibited neutrophil adhesion to lipopolysaccharide-stimulated HUVEC and T cell adhesion to TNF-stimulated HUVEC. These findings suggest that bruceine B may have anti-inflammatory activity.

The effect of ulinastatin on cutaneous microcirculation during inhalation of 100% oxygen in a rabbit ear chamber

This study aims to investigate the effects of ulinastatin, a human urinary trypsin inhibitor, on the cutaneous microcirculation during inhalation of 100% oxygen in the rabbit. Twenty-one rabbits having a rabbit ear chamber (REC), were divided into 2 groups: 11 rabbits without ulinastain treatment (Group C) and 10 rabbits with ulinastatin (Group U). After air inhalation, the inspired gas was changed to 100% oxygen. In Group U, 50,000 units of ulinastatin were administered before changing the concentration of inspired gas. The results suggests that ulinastatin may be useful for maintaining the cutaneous microcirculation during inhalation of 100% oxygen.