P712Non-neuronal cholinergic system prevents coronary vascular dysfunction in diabetic heart

Background

Diabetic individuals suffer extensive myocardial damage during ischemia due to impaired ATP production and coronary vascular dysfunction. The cardiomyocytes possess a non-neuronal cholinergic system (NNCS) as it has choline acetyltransferase (ChAT) to synthesize acetylcholine (ACh). ACh released from cardiomyocytes activates hypoxia-inducible factor-1 pathway in an auto/paracrine manner under non-hypoxic condition. Activation of this pathway via NNCS promotes angiogenesis and is a promising mechanism to target ischemia in diabetes.

Aim

To investigate if activation of NNCS could improve the coronary vasculature in diabetic heart.

Methods

Type-2 diabetic db/db mice with ventricle-specific ChAT transgene (db/db-ChAT-tg) and control db/db mice of 12- and 24-weeks old were used. Catheterization of the jugular vein and carotid artery was performed in combination with synchrotron radiation microangiography to visualize the in-vivo coronary circulation. Changes of the coronary circulation to ACh (10μg/kg/min) and sodium nitroprusside (SNP, 10μg/kg/min) were assessed. Immunofluorescence analysis was performed to measure the density of arterioles and capillaries ex-vivo.

Results

In comparison to db/db mice, the number of second and third order vessels was higher in the db/db-ChAT-tg mice of 12- and 24-weeks old under baseline condition. In response to ACh and SNP, number of third order vessels were further increased in the db/db-ChAT-tg mice of both ages. However, the magnitude of the diameter changes in db/db-ChAT-tg mice was comparable to that in db/db mice of both ages. Besides, the db/db-ChAT-tg mice had increased density of arterioles and capillaries compared to the db/db mice of both ages.

Conclusion

NNCS-induced angiogenesis prevents coronary vascular dysfunction in diabetic heart.

Sympathetic hyper-excitation in obesity and pulmonary hypertension: physiological relevance to the 'obesity paradox'

BACKGROUND

Within the lung, sympathetic nerve activity (SNA) has an important role in facilitating pulmonary vasodilation. As SNA is elevated in obesity, we aimed to assess the impact of sympathetic hyper-excitation on pulmonary vascular homeostasis in obesity, and its potential role in ameliorating the severity of pulmonary hypertension (PH); the well-documented 'obesity paradox' phenomenon.

METHODS

Zucker obese and lean rats were exposed to normoxia or chronic hypoxia (CH-10% O2) for 2 weeks. Subsequently, pulmonary SNA (pSNA) was recorded (electrophysiology), or the pulmonary microcirculation was visualized using Synchrotron microangiography. Acute hypoxic pulmonary vasoconstriction (HPV) was assessed before and after blockade of β1-adrenergic receptors (ARs) (atenolol, 3 mg kg(-1)) and β1+β2-adrenergic (propranolol, 2 mg kg(-1)).

RESULTS

pSNA of normoxic obese rats was higher than lean counterparts (2.4 and 0.5 μV s, respectively). SNA was enhanced following the development of PH in lean rats, but more so in obese rats (1.7 and 6.8 μV s, respectively). The magnitude of HPV was similar for all groups (for example, ~20% constriction of the 200-300 μm vessels). Although β-blockade did not modify HPV in lean rats, it significantly augmented the HPV in normoxic obese rats (β1 and β2 blockade), and more so in obese rats with PH (β2-blockade alone). Western blots showed, while the expression of pulmonary β1-ARs was similar for all rats, the expression of β2-ARs was downregulated in obesity and PH.

CONCLUSIONS

This study suggests that sympathetic hyper-excitation in obesity may have an important role in constraining the severity of PH and, thus, contribute in part to the 'obesity paradox' in PH.

Modulation of radial blood flow during Braille character discrimination task

PURPOSE

Human hands are excellent in performing sensory and motor function. We have hypothesized that blood flow of the hand is dynamically regulated by sympathetic outflow during concentrated finger perception. To identify this hypothesis, we measured radial blood flow (RBF), radial vascular conductance (RVC), heart rate (HR), and arterial blood pressure (AP) during Braille reading performed under the blind condition in nine healthy subjects. The subjects were instructed to read a flat plate with raised letters (Braille reading) for 30 s by the forefinger, and to touch a blank plate as control for the Braille discrimination procedure.

RESULTS

HR and AP slightly increased during Braille reading but remained unchanged during the touching of the blank plate. RBF and RVC were reduced during the Braille character discrimination task (decreased by -46% and -49%, respectively). Furthermore, the changes in RBF and RVC were much greater during the Braille character discrimination task than during the touching of the blank plate (decreased by -20% and -20%, respectively).

CONCLUSIONS

These results have suggested that the distribution of blood flow to the hand is modulated via sympathetic nerve activity during concentrated finger perception.

Altered sarcoplasmic reticulum function in rat diaphragm after high-intensity exercise

The present study examined the effects of acute high-intensity exercise on Ca(2+) uptake and release rates and Ca(2+)-adenosine triphosphatase (ATPase) activity of the sarcoplasmic reticulum (SR) from the costal diaphragm. The rats were run on a treadmill at an estimated requirement of 100% of maximal O2 consumption until fatigued (average time to exhaustion: 4.79 min). Muscle lactate and inorganic phosphate after exercise were increased by 65% (P < 0.05) and 35% (P < 0.05), respectively. With exercise, Ca(2+) uptake and release, which were detected in homogenates using the Ca(2+) fluorescent dye indo-1, were decreased by 24% (P < 0.05) and 22% (P < 0.05), respectively. The reduction in Ca(2+) uptake was paralleled by decreased activity of SR Ca(2+)-ATPase in both the absence and presence of Ca(2+) ionophore. These findings demonstrate that, in the diaphragm as well as in the locomotor muscles that have been explored in previous studies, the attenuations of the SR function is brought about by acute high-intensity exercise. These changes in the SR of the diaphragm may contribute, at least in part, to deteriorations in exercise tolerance and work productivity resulting from repetitive physical activities.

Reflex responses in plasma catecholamines caused by static contraction of skeletal muscle

To examine a hypothesis of whether static muscle contraction produces a release of catecholamines from the adrenal medulla via reflex stimulation of preganglionic adrenal sympathetic nerve activity induced by receptors in the contracting muscle, we compared the reflex responses in a concentration of epinephrine (Ep) and norepinephrine (NEp) in arterial plasma during static contraction and during a mechanical stretch of the hindlimb triceps surae muscle in anesthetized cats. Static contraction was evoked by electrically stimulating the peripheral ends of the cut L(7) and S(1) ventral roots at 20 or 40 Hz. Mean arterial pressure (MAP) and heart rate (HR) increased 23 +/- 3.1 mmHg and 19 +/- 4.3 beats/min during static contraction. Ep in arterial plasma increased 0.18 +/- 0.072 ng/ml over the control of 0.14 +/- 0.051 ng/ml within 1 min from the onset of static contraction, and NEp increased 0.47 +/- 0.087 ng/ml over the control of 0.71 +/- 0.108 ng/ml. Following a neuromuscular blockade, although the same ventral root stimulation failed to produce the cardiovascular and plasma catecholamine responses, the mechanical stretch of the muscle increased MAP, HR, and plasma Ep, but not plasma NEp. With bilateral adrenalectomy, the baseline Ep became negligible (0.012 +/- 0.001 ng/ml) and the baseline NEp was lowered to 0.52 +/- 0.109 ng/ml. Neither static contraction nor mechanical stretch produced significant responses in plasma Ep and NEp following the adrenalectomy. These results suggest that static muscle contraction augments preganglionic adrenal sympathetic nerve activity, which in turn secretes epinephrine from the adrenal medulla into plasma. A muscle mechanoreflex from the contracting muscle may play a role in stimulation of the adrenal sympathetic nerve activity.

A case of papillary meningioma with a t(1;4)(q44;q21)

We report the results of cytogenetic analyses of three cases of meningiomas. The first case, a papillary meningioma, showed only one cytogenetic abnormality, 46,XX,t(1;4)(q44;q21). In contrast, the other two benign fibroblastic meningiomas showed loss of chromosome 22. Loss and/or rearrangement of chromosomes other than chromosome 22 appears to be associated with a more aggressive clinical course. It is suggested that a sole cytogenetic abnormality with a normal chromosome 22 indicates an atypical nature of meningioma.

Assessment of long-distance running performance in elite male runners using onset of blood lactate accumulation

The purpose of this study was to evaluate the relationship between onset of blood lactate accumulation (OBLA) and long-distance running performance in order to examine whether OBLA can be a good predictor of long-distance running performance even in elite male runners with similar performance levels. Eleven highly-trained male long-distance runners participated in this study. The average running velocities of the individuals' running performance were 5.918 +/- 0.084 m.s-1 and 5.672 +/- 0.095 m.s-1 for 5000 m (V5000) and 10,000 m (V10000), respectively. The blood lactate concentrations and heart rate responses were measured immediately after field running, and the average value of running velocity corresponding to OBLA (VOBLA) was 5.447 +/- 0.132 m.s-1. Variations of these three velocities expressed as a coefficient of variance (CV) ranged from 1.4 to 2.4%. A strong inverse relationship between heart rate corresponding to OBLA (HROBLA) and performance was observed (r = -0.709, p < 0.02 for V5000 and r = -0.830, p < 0.01 for V10000), while there was a lack of significant relationship between VOBLA and performance (r = 0.293, NS for V5000 and r = 0.130, NS for V10000). Furthermore, the average value of HROBLA obtained in this study (174.5 +/- 8.2 b.min-1) was quite similar to that of the heart rate threshold reported by some previous researchers. In conclusion, VOBLA alone could not explain the small variation of long-distance running performance, and HROBLA should be used in place of VOBLA for evaluating long-distance running performance in elite runners with quite similar performance levels.

Role of the claustrum in convulsive evolution of visual afferent and partial nonconvulsive seizure in primates

PURPOSE

We tested cross-species validity of the role of the claustrum in the convulsive evolution of the visual afferent and amygdaloid seizure and the specificity of the claustral lesioning effect.

METHODS

In 7 Senegalese baboons, we examined the effect of unilateral claustral lesioning on generalized convulsive seizures either kindled from the amygdaloid nucleus (AM) and cingulate cortex (CG) or induced by intermittent photic stimulation (IPS) after systemic administration of D,L-allylglycine (AG).

RESULTS

A lesioned area common to all animals was the anterior half of the left claustrum. Postoperative restimulation of the kindled left AM or CG evoked only nonconvulsive seizures. When few convulsive seizures emerged in 1 CG-kindled animal, they were mirror image of the kindled seizure and arose from the nonlesioned right hemisphere. Restimulation of the kindled right AM or CG reactivated kindled seizures. An IPS-induced generalized convulsive seizure was transformed into a secondarily generalized seizure arising from the nonlesioned right hemisphere.

CONCLUSIONS

The primate claustrum regulates the convulsive evolution of partial seizures originating from nonmotor structures such as the AM and CG and also regulates the convulsive development that follows IPS. Our findings suggest that predisposed susceptibility expressed at the claustrum may be involved in the clinical variation with respect to convulsive evolution of nonmotor partial seizures and convulsive susceptibility to IPS in human primates.

Phosphorylation-independent inhibition by intracellular cyclic nucleotides of brain inwardly rectifying K+ current expressed in Xenopus oocytes

An inwardly rectifying K+ current, which was heterologously expressed in Xenopus oocytes, was inhibited by isoproterenol, a fadrenergic agonist. Poly(A)+ mRNA isolated from guinea-pig brain was injected into oocytes 2-3 days before experiments. Isoproterenol inhibition of the K+ current was time-and voltage-dependent: the inhibition became faster and more pronounced as the command voltage steps were applied to more negative potentials. This inhibition was prevented by propranolol. Dibutylyl cyclic (dB-c) AMP could mimic the effect of isoproterenol, while injection of the catalytic subunit of cAMP-dependent protein kinase into the oocytes did not affect the K+ current. Inhibitors of the protein kinases, WIPTIDE and H-8, did not prevent the inhibition by dB-cAMP. Furthermore, dB-cGMP also inhibited the K+ current in a similar time- and voltage-dependent manner. We propose that the phosphorylation-independent action of cyclic nucleotides mediates beta-adrenergic inhibition of brain inwardly rectifying K+ channels expressed in Xenopus oocytes.

Cingulate kindling in Senegalese baboons, Papio papio

Kindling of the cingulate cortex in the Senegalese baboon Papio papio led to a protracted nonconvulsive seizure state characterized by immobile staring with (anterior cingulate, AC) or without (posterior cingulate, PC) widening of eyelids and neck flexion, followed by postictal visual searching behavior. Despite early bilateral spread of EEG discharges, ictal and interictal patterns remained persistently asymmetric. Secondary generalization was rapid and predictable once contralateral lower facial twitching associated with sustained adversion developed. After the primary site had been kindled, stimulation of the contralateral homotopic posterior cingulate cortex readily produced afterdischarge. However, it remained localized and kindling growth did not occur. The findings suggest that (a) the cingulate cortex can support nonconvulsive seizures; (b) cingulate seizures are accompanied by asymmetric convexity EEG discharges indicating its lateralized onset; (c) further evolution to convulsive seizures after kindling of cingulate cortex requires access to the ipsilateral frontocentral cortex responsible for facial twitching; and (d) the development of focal epileptogenesis at one cingulate site interferes with clinical seizure development at the homotopic contralateral site.

Symptomatic Chiari malformation and associated pathophysiology in pediatric and adult patients without myelodysplasia

The clinical characteristics of eight pediatric and five adult patients with Chiari malformation were evaluated. Six pediatric and five adult patients had associated syringomyelia. All patients initially underwent a suboccipital craniectomy with upper cervical (C-1 and/or C-2) laminectomy and duraplasty, and/or shunting procedures. The clinical characteristics of the pediatric and adult groups were compared. The mean interval between onset of symptoms and operation was shorter in the pediatric group (3 yrs 6 mos) than in the adult group (7 yrs 1 mo). Pediatric patients without syringomyelia had the shortest mean interval of 1 year 8 months. Preoperatively, the clinical features were more severe in the adult patients than in the pediatric patients. Postoperatively, seven of eight pediatric patients improved and one stabilized, while two of five adult patients improved, one stabilized, and in two the disease continued to progress despite multiple corrective procedures. Cine magnetic resonance imaging revealed correction of the abnormal cerebrospinal fluid (CSF) flow at the craniovertebral junction and decreased to-and-fro movement in the syrinx after posterior fossa decompression, which were closely correlated with the improvement of clinical features in pediatric patients. However, adult patients required further procedures because of the multifactorial nature of the disease. Evaluation of abnormal CSF pathways at the craniovertebral junction is important for investigating the pathogenesis of Chiari malformation and associated syringomyelia.

Molecular cloning and characterization of the platelet-activating factor receptor gene expressed in the human heart

PAF decreases cardiac contractility and blood pressure. To characterize the cardiac PAF receptor, we screened a human ventricular cDNA library in a low stringency condition, using a PCR product derived from guinea pig lung PAF receptor as a probe. Four clones were obtained and named HV1-4. In Xenopus oocytes injected with cRNA derived from HV3 or 4 but not from HV1 or 2, PAF elicited a Ca(2+)-activated Cl- current. HV3 and HV4 were duplicate clones, encoding a 342 amino-acid polypeptide which was identical to that of the human leukocyte PAF receptor. However, a portion of the 5' untranslated region of HV3 (or 4) was different from that of the leukocyte receptor cDNA. Northern blotting of human ventricles and atria using the HV3 insert showed a single band of approximately 4 kb. These results suggest a tissue-specific translational mechanism responsible for regulation of the expression of the PAF receptor mRNA in these tissues.

[Clinicopathological evaluation of EVAL embolization in arteriovenous malformations]

The clinical and pathological aspects of two large arteriovenous malformations which were removed totally after preoperative embolization using ethylene vinyl alcohol copolymer (EVAL) were studied. The material, which is not adhesive, is handled easily during the procedure of embolization. However, it involves some risks because it might migrate to and occlude the normal branches of the brain and pass through the nidus to the venous system. Histopathological study of AVM nidus which was removed showed embolic materials within the vessels and inflammatory reaction of the vessel wall and its surrounding tissue. There were patchy hemorrhages within the AVM nidus and its surrounding brain tissue. Recanalization was also found within the occluded vessels. These findings suggest that preoperative embolization has some risk of causing intracerebral hemorrhage after the embolization. AVM should be removed surgically as a radical treatment if the patient is able to tolerate the operation.

Treatment of infective endocarditis with granulocyte colony-stimulating factor

Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein hormone which stimulates the proliferation and differentiation of a subset of granulocyte precursors and enhances some functional activities of mature neutrophils. We tested the effects of G-CSF on a patient with intractable infective endocarditis. The white blood cell count was increased 3-fold and the inflammatory reactions such as C-reactive protein and erythrocyte sedimentation rate were completely normalized without any side effects. This is the first report describing the use of G-CSF for infective endocarditis. Administration of G-CSF might be suitable for treating intractable infections which cannot be controlled by antibiotics alone.

[Clinicopathological study of meningiomas of the tentorium and its surrounding structures]

We report the clinical features, radiological studies, operative procedures and results, and follow-up data in 29 patients with meningiomas of the tentorium and its surrounding structures. The cases represented 22.5% of all the intracranial meningiomas operated on in a 15 year period and were divided into three groups, depending on their main attachments, tentorial, cerebellopontine angle (dorsal aspect of the petrous ridge) and others. Tumor size was generally large and 13 cases were larger than 5 cm. The most common tumor site was along or near the superior petrosal sinus and transverse-sigmoid junction in cases involving the tentorium, and medial to the porus acousticus in cases involving the cerebellopontine angle. Different operative approaches to these tumors were carried out, depending on their location. The tumors in the lateral or medial petrous ridge were approached mainly with a suboccipital craniectomy using a retromastoid incision. Total removal was carried out in 80% of the tentorial cases, in 46.2% of cerebellopontine angle cases, and in the 83.3% in the others. Total operative mortality rate was zero. Follow-up periods ranged up to 5 years 5 months in the tentorial cases, 4 years 6 months in cerebellopontine angle cases, and 7 years 1 month in the others. Long-term results were good in 21 cases (72.4%), fair in 3 cases (10.3%) and poor in 2 (6.9%). Three patients died due to tumor recurrence. One of them suffered lung metastasis, and two of them suffered extensive local recurrences. We recommend the retromastoid approach combined with the petrosal approach, if the CPA tumor is large enough and extends to the retroclival region.

cDNA cloning of a myosin heavy chain isoform in embryonic smooth muscle and its expression during vascular development and in arteriosclerosis

Adult rabbit smooth muscles contain two types of myosin heavy chain (MHC) isoforms, SM1 and SM2 which are generated through alternative RNA splicing from a single gene (Nagai, R., Kuro-o, M., Babij, P. & Periasamy, M. (1989) J. Biol. Chem. 264, 9734-9737). We previously reported that the expression of SM1 and SM2 during vascular development is differentially regulated at the level of RNA splicing, whereby SM1 is constitutively expressed from early development but SM2 appear after birth (Kuro-o, M., Nagai, R., Tsuchimochi, H., Katoh, H., Yazaki, Y., Ohkubo, A. & Takaku, F. (1989) J. Biol. Chem. 264, 18272-18275). We also demonstrated that embryonic vascular smooth muscles contain a third type of MHC isoform, referred to as SMemb in this report, which comigrates on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with SM2. In the present study we have isolated and characterized a cDNA clone (FSMHC34) for SMemb. FSMHC34 encodes the light meromyosin region including the carboxyl terminus and showed 70% amino acid sequence identity with SM1 or SM2. SMemb is a nonmuscle-type MHC and identical with brain MHC, but clearly distinct from 196-kDa nonmuscle MHC in cultured smooth muscle cells. The expression of SMemb was predominant in embryonic and perinatal aortas, but down-regulated with vascular development. Interestingly SMemb was reexpressed in proliferating smooth muscle cells of arteriosclerotic neointimas. These results suggest that smooth muscle proliferation is coupled to the expression of SMemb and that dedifferentiation of smooth muscles toward the embryonic phenotype is involved in the mechanisms underlying atherosclerosis.

Surgical results of brain metastasis from lung cancer--prognostic factors

Twenty-five patients receiving surgical treatment for brain metastasis from lung cancer were retrospectively studied to evaluate the prognostic factors for survival time. Twenty-two patients had died of respiratory distress by April, 1989. Favorable prognostic factors derived from the median survival time (MST) in these patients included; 1) resection of primary tumor (MST 10 months); 2) total or subtotal removal of metastatic tumor (MST 6.5 months); 3) adenocarcinoma (MST 13 months); 4) metachronous onset of brain metastasis (MST 12 months); 5) single metastasis (MST 8 months). These results suggest that therapy for the primary lung cancer is important before surgery for metastatic brain tumor.

Functional identification of the transcriptional regulatory elements within the promoter region of the human ventricular myosin alkali light chain gene

We have identified and functionally characterized DNA sequences that regulate the expression of the human ventricular/slow twitch isoform of myosin alkali light chain (VLC1) gene. By using primer extension and S1 nuclease mapping techniques, we have shown that the VLC1 gene is transcribed from the identical site in the ventricular and slow twitch skeletal muscles. Comparison of the VLC1 sequences from +1 to -1296 in the genes for human and mouse showed that the 5'-proximal flanking region, up to about 220 nucleotides, was highly conserved (83% homology). To determine the location of sites that may be important for the function of the VLC1 promoter, a series of transient expression vectors containing progressive deletions of the VLC1 gene 5'-flanking sequence fused to the bacterial chloramphenicol acetyltransferase (CAT) gene was introduced into myogenic and nonmyogenic cells. Deletion mutagenesis of sequences between -357 and +40 revealed the presence of positive and negative activity in all the cells tested. We demonstrated that the minimal promoter sequence required to generate muscle cell-specific expression is the region between -94 to -64 upstream from the cap site and a sequence element located between -107 and -94 was found to have a positive effect in both myogenic cells and nonmyogenic cells. These two proximal regions located between -107 and -64 appear to act together to determine the cell type-specific high level expression of the VLC1 gene in muscle cells. Competition gel retardation assays revealed that the CArG sequence located between -96 and -87 interacts specifically with nuclear extracts from myogenic and nonmyogenic cells and compete for binding with the CArG sequence present in the human cardiac alpha-actin gene and with the serum response element of the c-fos gene. These results strongly suggested that similar, if not identical, the CArG box binding proteins interact with the functionally different promoter element in the VLC1, cardiac alpha-actin, and c-fos genes.

The myosin gene switching in human cardiac hypertrophy

Cardiac hypertrophy is associated with qualitative as well as quantitative changes in myocardial cells. To analyze the molecular basis of isozymic transitions of cardiac myosins in response to pressure overload, we have constructed and characterized two types of myosin heavy chain (MHC) cDNA clones, specifying alpha- and beta-MHCs, and two types of myosin alkali light chain cDNA clones, complementary to atrial type (ALC1) and ventricular type (VLC1) mRNAs from a human fetal heart cDNA library. Using the S1 nuclease mapping procedure, we showed that the MCH isozymic transitions from alpha- to beta-MHC in the pressure overloaded atria are produced by changes in the relative level of alpha- and beta-MHC gene expression. In addition, we observed that the expression of VLC1 gene is also induced in the atria subjected to severe pressure overload. Thus, it appears that the increased expression of VLC1 gene, together with the isogene switch from alpha- to beta-MHC gene, may participate in the adaptation of myocardium to new functional requirement. Then, to get a better understanding of the genetic mechanisms involved in the regulation of isogene expression, we have isolated and sequenced genomic clone for VLC1 isoform. Sequence analysis has identified multiple potential cis regulatory elements within a 686-bp upstream region. This region includes 28-bp alternating purine/pyrimidine sequences and two segment exhibiting homology to consensus sequence proposed for viral and cellular enhancer elements. In particular, a comparison of the VLC1 upstream gene sequence with those available for several muscle-specific genes revealed that CC(A + T-rich)6GG elements and CATTCCT sequence are conserved. These results suggested that CArG box (-96 to -87) has an important role in the positive regulation of the VLC1 gene and this element may be involved in the co-regulation of VLC1 and cardiac alpha-actin genes.

Expression of major histocompatibility complex class I antigen in murine ventricular myocytes infected with Coxsackievirus B3

Evidence has accumulated that T cell-mediated autoimmunity plays an important role in the pathogenesis of viral myocarditis. T lymphocytes are known to recognize antigen-presenting cells, such as virus-infected cells, being restricted by syngeneic major histocompatibility complex (MHC) antigens. To clarify in more detail the immunological mechanisms involved, we induced acute viral myocarditis in C3H/He mouse ventricles with coxsackievirus B3 (CVB3) and examined, by immunofluorescence, the expression of MHC class I and II antigens, previously reported not to be expressed by normal cardiac myocytes. Furthermore, to confirm the expression of MHC class I (H-2Kk) antigens at the cellular level, we treated cultured cardiac myocytes with interferon gamma and examined the antigen expression by immunofluorescence and Northern blot hybridization, using an antisense RNA probe for MHC messenger RNA. Our observations demonstrated 1) CVB3-induced myocarditis resulted in the enhanced expression of MHC class I (H-2Kk) gene product on the surface of cardiac myocytes but low or undetectable levels of MHC class II or H-2Dk gene products, and moderate focal transient (days 5-7) expression of both MHC class I (Kk + Dk) region gene products and MHC class II antigens were induced on capillary endothelial cells; 2) murine fetal cardiac myocytes cultured in vitro in the presence of interferon gamma similarly were shown to express marked levels of MHC class I (H-2Kk) but low to undetectable levels of the H-2Dk gene product; however, weak to moderate MHC Class II antigens were expressed by these cultured myocytes; and 3) the expression of MHC antigens in cardiac myocytes was modulated at the transcriptional level.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of long-term treatment with beta-blocker on cardiac hypertrophy in SHR

Recent studies suggest that beta-blocker treatment may attenuate cardiac hypertrophy induced by pressure overload in the spontaneously hypertensive rat (SHR), but the effect of this therapy on the reconstitution of the intracellular constituents in the heart that occurs during the development of cardiac hypertrophy has not been examined. In this study, we investigated the effect of chronic administration of carteolol (4 mg/kg/day p.o.) or propranolol (20 mg/kg/day p.o.), beta-blockers with distinct modes of action, on the composition of cardiac myosin isozymes and histological findings as well as heart weight. Therapeutic periods were 4, 12 or 30 weeks. Though blood pressure was not significantly reduced, the development of cardiac hypertrophy was suppressed as evidenced by left ventricular weight in both groups of carteolol- and propranolol-treated SHR for all therapeutic periods. Again, beta-blocker treatment for 12 weeks alleviated myocardial degeneration and reactive fibrosis which were observed in all cases of age-matched untreated SHR. However the extent of the transition of cardiac myosin isozymes from V1 to V2 or V3 were essentially the same among all groups including untreated SHR. These results indicate that chronic administration of beta-blockers attenuates the development of cardiac hypertrophy and degeneration without affecting the transition of myosin isozymes which is thought to be a kind of biochemical adaptation of the myocardium to overload.

Molecular adaptation to pressure overload in human and rat hearts

The process of enlargement of the heart due to overload involves a significant reconstitution of the organ including myocytes and intracellular constituents. We demonstrated the distribution of two types of cardiac myosin heavy chains (HC alpha and HC beta) in the human heart using monoclonal antibodies. The ventricle comprised mainly HC beta which has low ATPase activity, whereas the atrium was predominantly composed of HC alpha which has high ATPase activity. We also demonstrated isozymic transition of HC alpha to HC beta in the human atrium and ventricle by hemodynamic overload, regarded as a compensatory mechanism to meet an increased demand in work. To examine the molecular mechanism for the expression of these HCs, we have isolated human HC alpha and HC beta cDNA clones from a fetal heart cDNA library. Comparison of the nucleotide and amino acid sequences deduced from the DNA between these cDNA clones showed 91 and 96% homology, respectively. Using HC alpha and HC beta gene-specific sequences, we demonstrated that the transition of HC alpha to HC beta in the overloaded human heart was induced by the expression of HC beta-gene. To determine the role of cellular oncogenes in the process of cardiac growth and hypertrophy, we examined the expression pattern of eight cellular oncogenes during the developmental stage and pressure-overloaded hypertrophy of the rat heart by Northern blot analysis. c-fos, c-myc and c-Ha-ras were expressed in the heart in response to pressure overload and in a stage-specific manner, suggesting that these cellular oncogenes participate in the normal developmental process and hypertrophy of the heart. We also cloned the genes of which expression level was rapidly changed by pressure overload by differential hybridization technique. Our results suggest that clone 4 may be involved in the molecular mechanism for the development of cardiac hypertrophy due to overload.

Developmentally regulated expression of vascular smooth muscle myosin heavy chain isoforms

Two types of smooth muscle myosin heavy chain (MHC) isoforms, SM1 and SM2, were recently identified to have different carboxyl termini (Nagai, R., Kuro-o, M., Babij, P., and Periasamy, M. (1989) J. Biol. Chem. 264, 9734-9737). SM1 and SM2 are considered to be generated from a single gene through alternative RNA splicing. In this study we investigated expression of vascular MHC isoforms during development in rabbits at the mRNA, protein, and histological levels. In adults, all smooth muscle cells reacted with both anti-SM1 and anti-SM2 antibodies on immunofluorescence, suggesting the coexpression of SM1 and SM2 in a single cell. In fetal and perinatal rabbits, however, only anti-SM1 antibody consistently reacted with smooth muscles. Reactivity with anti-SM2 antibody was negative in the fetal and neonatal blood vessels and gradually increased during 30 days after birth. These developmental changes in SM1 and SM2 expression at the histological level coincided with mRNA expression of each MHC isoform as determined by S1 nuclease mapping, indicating that expression of SM1 and SM2 is controlled at the level of RNA splicing. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of myosin from fetal and perinatal aortas revealed the presence of large amount of SM2. Interestingly, fetal SM2 did not cross-react with our anti-SM2 antibody on immunoblotting. We conclude that expression of SM1 and SM2 are differentially regulated during development and that a third type of MHC isoform may exist in embryonic and perinatal vascular smooth muscles.

[Cosmetic cranioplasty using the bone chips and Biobond (EDH-adhesive): technical note]

A new and simple cosmetic procedure for the prevention of skin depression produced by burr-holes was presented. A mixture of the bone chips obtained at craniotomy and Biobond in a volume ratio of 7:3 was used to fill the bone defect of the burr-holes in 65 cases. The postoperative appearance was excellent cosmetically. This mixture had good plasticity, and could be formed into any irregular shape desired, and there was no increase in the incidence of infectious complications.

Atrial natriuretic peptide distribution in fetal and failed adult human hearts

The distributions of atrial natriuretic peptide (ANP) in human hearts during the developmental stage and in adult pathological states was examined with an antibody specific to human alpha-ANP. With immunoblotting and immunofluorescence methods, we found that a 17-kDa protein, which is a pro ANP, was expressed in human fetal ventricles, in which the numbers of myofibers containing ANP granules were more abundant in the subendocardial region than the subepicardial region. As determined by radioimmunoassay, the content of immunoreactive ANP (per milligram protein) in the developing heart was greatest in the left atrium and occurred decreasingly in the right atrium, right ventricle, and left ventricle, respectively. Because ANP content in the left ventricle declined during the progress of gestation in developing hearts and because it was very low, if ever detectable, in normal adult hearts, ventricular ANP expression appears to be developmentally regulated from the early gestational stage. However, it was reexpressed in the ventricles of patients who had suffered from severe congestive heart failure. In this situation, we found that the ventricular ANP expression was more marked in patients with dilated cardiomyopathy than in patients with severe valvular disease. Interestingly, in the ventricles of patients with dilated cardiomyopathy, ANP contents were higher in the left ventricular free wall than in the right ventricular free wall, although the left ventricular subendocardium contained more ANP than the subepicardium, showing a transmural gradient similar to that expressed in fetal ventricles. Thus, the expression of ANP in human ventricles is developmentally regulated from the early gestational stage, and even adult ventricular myofibers can synthesize ANP during severe congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular cloning and characterization of human atrial and ventricular myosin alkali light chain cDNA clones

We have isolated essentially full-length cDNA clones for atrial (ALC1) and ventricular (VLC1) myosin alkali light chains from a human fetal heart cDNA library. Comparison of overall nucleotide sequences of ALC1 and VLC1 cDNA clones has revealed that, while these two inserts show significant DNA sequence homology (78.4%) with respect to their coding regions, the 5'- and 3'-untranslated regions are highly divergent. Our statistical analysis suggests that human ALC1 and VLC1 diverged approximately 300 million years ago, during the time of separation of birds and mammals. RNA blot analysis shows that ALC1 mRNA is expressed in fetal ventricular and fetal skeletal muscles as well as fetal and adult atrial muscles and VLC1 mRNA is expressed in adult slow skeletal muscle as well as fetal and adult ventricular muscles. Southern blot analysis indicates that each protein is encoded by a single gene. Finally, we show that VLC1 mRNA is induced in pressure-overloaded human atrium.

Molecular cloning and characterization of human cardiac alpha- and beta-form myosin heavy chain complementary DNA clones. Regulation of expression during development and pressure overload in human atrium

We have constructed and characterized two types of myosin heavy chain (MHC) cDNA clones (pHMHC2, pHMHC5) from a fetal human heart cDNA library. Comparison of the nucleotide and deduced amino acid sequences between pHMHC2 and pHMHC5 shows 95.1 and 96.2% homology, respectively. The carboxyl-terminal peptide and 3'-untranslated (3'-UT) regions are highly divergent and specific for these cDNA clones. By using the synthetic oligonucleotide probes that are complementary to the unique 3'-UT regions of these cDNA clones, we demonstrate that pHMHC2 is exclusively transcribed in the atrium, whereas the mRNA for pHMHC5 is predominantly expressed in the ventricle. This result indicates that pHMHC2 and pHMHC5 code for alpha- and beta-form MHCs, respectively. Furthermore, we show that beta-form MHC mRNA is expressed in adult atrium at a low level but scarcely expressed in fetal atrium. Finally, we demonstrate that MHC isozymic transition in pressure-overloaded atrium is, at least in part, regulated at a pretranslational level.

Differences in response of myosin isozyme transition of ordinary and specialized myocardium to overload

To investigate the response of myosin isozyme transition in specialized myocardium to cardiac overload, we examined immunohistochemically the distribution of myosin isozymes in sinus node cells of overloaded canine atria, using the monoclonal antibodies CMA19 and HMC14, which are specific for atrial myosin heavy chain (alpha-HC) and ventricular myosin heavy chain (beta-HC), respectively. Overloading in canine right atria was induced by artificial tricuspid valve regurgitation and pulmonary stenosis. Right atrial mean pressure rose to 15-20 mm Hg (n = 4) 2 months after surgery. In the working myocardium, cardiac overload caused redistribution of myosin isozymes, alpha-HC to beta-HC. Compared with the normal right atria, fewer myocytes were labeled with CMA19, but more were labeled with HMC14. However, the reactivity of sinus node cells with CMA19 and HMC14 was not changed between normal and overloaded right atria, indicating no redistribution of myosin heavy chain isozymes, alpha-HC to beta-HC. These results suggest that isozymes in myosin heavy chains in the specialized myocardium are protected from overload effects by their firm cytoskeletal framework or other mechanisms.

Heterogeneity of beta-type myosin isozymes in the human heart and regulational mechanisms in their expression. Immunohistochemical study using monoclonal antibodies

To investigate the existence of heterogeneity of beta-type myosin isozymes (HC beta) in human hearts, immunohistochemical studies using monoclonal antibodies (MoAbs) raised against human ventricular myosin heavy chains were performed. Two types of MoAbs recognized some muscle fibers in the atrium, whereas both reacted with all ventricular muscle fibers. Since atrial muscle fibers reactive with each MoAb were found to be clearly different, the existence of two immunologically distinct HC beta (beta 1, and beta 2) was suggested in the atrium. By using affinity chromatography, two molecular variants of HC beta were isolated from the bovine atrium, and differences in the primary structure of beta 1 and beta 2 were confirmed by analysis of peptides produced by chymotryptic digestion. In pressure-overloaded human atria, myofibers containing beta 1 and/or beta 2 increased in accordance with decrement of myofibers containing alpha-type myosin isozyme (P less than 0.01). But they differed in expression during the developmental stage, since beta 2 did not exist in the early embryonic bovine heart, but beta 1 did. Thus, there are two distinct HC beta whose expression is regulated by at least two factors: pressure overload and developmental stage.

Quantitative relationship between left ventricular function and serum cardiac myosin light chain I levels after coronary reperfusion in patients with acute myocardial infarction

To estimate the extent of myocardial infarction after coronary artery reperfusion, serum levels of cardiac myosin light chain (LC) I and creatine kinase (CK) were determined serially in 49 patients with acute myocardial infarction. Intracoronary thrombolysis was successful in 25 patients (reperfusion group), and 24 patients were treated in a conventional manner (control group). The peak level of CK appeared significantly earlier in the reperfusion group (11.3 +/- 3.1 hr, mean +/- SD) than in the control group (21.6 +/- 7.2 hr). Cumulative release of CK was significantly related to angiographically determined left ventricular ejection fraction 1 month after the attack in both groups (r = -.50; -.45, respectively). However, the amount of cumulative release of CK in the reperfusion group was greater compared with that in those with the same left ventricular ejection fraction in the control group. Peak appearance time of LCI was almost equal in the two groups (3.8 +/- 1.4 vs 3.9 +/- 1.2 days). Peak levels of LCI were related to the left ventricular ejection fraction in the reperfusion group (r = -.63) and in the control group (r = -.74), and the slopes of their regression lines were similar. The cardiac index obtained on the day of onset in the two groups was related to peak levels of LCI but not to total release of CK. These results suggest that serum levels of LCI reflect the changes in left ventricular function after acute myocardial infarction, regardless of the presence of coronary reperfusion. Thus, serial determinations of LCI in serum facilitate noninvasive assessment of the effects of intracoronary thrombolysis on infarct size.

Distribution of cardiac myosin isozymes in cardiomyopathy: immunohistochemical and gene analysis

We characterized cardiac myosin isoforms by immunohistochemical approaches using monoclonal antibodies and demonstrated the existence of a distinctive type of cardiac myosin heavy chain which predominates in the fetal stage but is depressed during postnatal development. Furthermore, we showed that this type of cardiac myosin heavy chain was markedly expressed in patients with dilated cardiomyopathy. The results suggested that the pathologic process involved in dilated cardiomyopathy affects myocardial differentiation by the inhibition of the myosin gene switching that normally occurs during muscle maturation. However, we could not find any polymorphism in myosin gene in our population sample of dilated cardiomyopathy. The pathophysiological role of fetal type cardiac myosin expression in dilated cardiomyopathy will be clarified by the characterization of the myosin near future.

Expression of myosin isozymes during the developmental stage and their redistribution induced by pressure overload

Cardiac muscles contain at least two isozymes--referred to as alpha(HC alpha) and beta(HC beta)--of the myosin heavy chain. The proportional ratio of these isozymes varies depending upon the developmental stage and the physiological and/or the hormonal milieu of the cell. Using monoclonal antibodies (MoAb) specific for human cardiac HC alpha and HC beta, we have examined the expression of these isozymes in fetal through adult cardiac tissues and investigated whether isozymic redistribution occurs in pressure overloaded human ventricles. We found that although HC alpha was expressed in the atrium from the early embryonic stage, in embryonic ventricular myofibers, only HC beta was expressed without expression of HC alpha, but some myofibers replace HC beta by HC alpha after birth, and these HC alpha containing ventricular myofibers were found to be decreased by pressure overload, which suggested that isozymic redistribution from HC alpha to HC beta also occurred in the ventricles, as well as the atrium. In addition, we also found two subtypes of HC beta (beta 1, beta 2) in the human heart. In the ventricle, both beta 1 and beta 2 was present in all myofibers; in contrast, some myofibers contained beta 1 or beta 2 or both with or without expression of HC alpha in the atrium. beta 1 and beta 2 were distinctive in their expression during the developmental stage, since beta 1 was present in the embryonic heart from the early developmental stage, whereas beta 2 was not present in the early embryonic heart, but began to be expressed in the late embryonic stage.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of Takayasu's disease with ruptured carotid aneurysm

Recently, a number of cases of Takayasu's disease having dilatative or aneurysmal lesions have been reported. Such lesions have come to be considered important manifestations of Takayasu's disease. A case, whose right common carotid artery perforated spontaneously and became a pseudoaneurysm, without any other stenotic lesion is presented with a review of the literature. Surgical treatment was performed successfully.

Isolation and characterization of two isozymes of myosin heavy chain from canine atrium

To clarify the characteristics of myosin isozymes in the atrium, we fractionated two isoforms of myosin heavy chain (HC), atrial HC alpha (A-HC alpha) and HC beta (A-HC beta), from the canine heart by affinity chromatography, using monoclonal antibodies specific for HC alpha (CMA19) and HC beta (HMC50), respectively, and then compared their peptide composition and enzymatic properties with those of ventricular HC alpha (V-HC alpha) and HC beta (V-HC beta). The reactivity of these isozymes with three monoclonal antibodies revealed that there are at least three different epitopes between A-HC alpha and A-HC beta. Differences in the primary structure of A-HC alpha and A-HC beta were confirmed by one- and two-dimensional gel electrophoretic analyses of these peptides, produced by digestion with alpha-chymotrypsin and cyanogen bromide (CNBr). A-HC alpha and V-HC alpha were indistinguishable proteins, and A-HC beta was also very similar to V-HC beta. Furthermore, there were differences between A-HC alpha and A-HC beta in their Ca2+-activated ATPase activities. The ATPase activity of A-HC beta was lower than that of A-HC alpha and was similar to that of V-HC beta. We concluded that there are two different isozymes of myosin heavy chain in the atrium (A-HC alpha and A-HC beta), as well as in the ventricle (V-HC alpha and V-HC beta), and that A-HC beta is very similar to V-HC beta, the predominant form of ventricular myosin, in its molecular structure and enzymatic activity.

Distribution of cardiac myosin isozymes in human conduction system. Immunohistochemical study using monoclonal antibodies

To determine the presence and distribution of cardiac myosin isozymes in the human conduction system, we performed an immunohistochemical study using monoclonal antibodies CMA19 and HMC14, which are specific for myosin heavy chains of human atrial type (alpha-type) and ventricular type (beta-type), respectively. Serial frozen sections of human hearts were obtained from autopsy samples and examined by indirect immunofluorescence. Alpha-type was found in all myofibers of sinus node and atrio-ventricular node, and in 55.2 +/- 10.2% (mean +/- SD, n = 5) of the myofibers of ventricular conduction tissue, which consists of the bundle of His, bundle branches, and the Purkinje network. In contrast, beta-type was found in all myofibers of the atrio-ventricular node and ventricular conduction tissue, whereas almost all myofibers of the sinus node were unlabeled by HMC14. Although the number of ventricular myofibers labeled by CMA19 was small, the labeled myofibers were more numerous in the subepicardial region than in the subendocardial region. These findings show that the gene coding for alpha-type is expressed predominantly in specialized myocardium compared with the adjacent ordinary working myocardium.

Applications of anticardiac myosin monoclonal antibodies in the diagnosis of heart disease

We have developed anticardiac myosin antibodies, especially monoclonal antibodies, for helping in the diagnosis of heart disease. Our investigations were divided into three research projects. We visualized the distribution of myosin isozymes in human atrial and ventricular myocardium by an immunofluorescence staining method using monoclonal antibodies specific for individual human cardiac myosin isozymes. We also revealed the redistribution of these cardiac myosin isozymes in an overloaded condition. The isozymic pattern of cardiac myosin was changed from the atrial type to the ventricular type in the overloaded atrium. This isozymic redistribution can be considered as physiological adaptive mechanism to meet increased cardiac work during overload. We developed a new method of imaging for myocardial infarction by single photon emission tomography using labelled monoclonal antibody specific for cardiac myosin heavy chain. Specific localization of the labelled antibody was demonstrated in the infarcted area and no accumulation of radioactivity was shown in the bone matrix as observed in 99mTc pyrophosphate images. We developed a sensitive radioimmunoassay of cardiac myosin light chain I (LCI) and demonstrated that peak serum levels of LCI in the patients with acute myocardial infarction correlated well with the left ventricular ejection fraction. Furthermore, LCI release from the infarcted myocardium was not affected by coronary reperfusion due to intracoronary thrombolysis. Thus, serial determinations of serum LCI better quantify the extent of myocardial damage even after coronary reperfusion in acute myocardial infarction.

Distribution of myosin isozymes in human atrial and ventricular myocardium: comparison in normal and overloaded heart

We have prepared monoclonal antibodies specific for either atrial or ventricular myosin and defined the isomyosin composition of myocardium in normal and overloaded human hearts. In the atrial myocardium, normal isozymic pattern was V1 dominant which converted to being V3 dominant in an overloaded condition. In contrast, normal isomyosin pattern of the ventricular myocardium was exclusively V3 dominant, and only a small change in the proportion of isomyosin was observed in an overloaded condition. From this, we conclude that isozymic changes in cardiac myosin could occur in the human heart to meet increased work induced by cardiac overload. However, the physiological importance of these isomyosin redistributions in human myocardium seems to be much greater in the atrium than in the ventricle, since larger amounts of V1 isomyosin which could be transformed to V3 isomyosin were present in the atrial myocardium.

Isozymic changes in myosin of human atrial myocardium induced by overload. Immunohistochemical study using monoclonal antibodies

An immunohistochemical study using monoclonal antibodies specific for the heavy chains of either human atrial (HC alpha) or ventricular (HC beta) myosin was performed to clarify the distribution of each isozyme in normal as well as pressure-overloaded human hearts. In normal human ventricles, all muscle fibers were stained by a monoclonal antibody (HMC14) specific for HC beta, whereas a small number of fibers reacted with a monoclonal antibody (CMA19) specific for HC alpha. In contrast, in normal human atria, almost all muscle fibers were stained by CMA19, and a relatively larger number of muscle fibers also reacted with HMC14. Furthermore, in pressure-overloaded atria, muscle fibers reactive with HMC14 were strikingly increased while those reactive with CMA19 showed a corresponding decrease. The extent of this isozymic redistribution was in good correlation with atrial pressure. These results not only confirmed the existence of isoforms of myosin heavy chain in human hearts, but also demonstrated that redistribution of iso-myosins could occur as an adaptation to pressure overload.