The failure of retrograde continuous warm-blood cardioplegia to resuscitate cardiac function in experimental acute coronary artery occlusion and reperfusion

The effects of retrograde continuous warm-blood cardioplegia (RCWBC) on myocardial preservation during surgical revascularization for acute coronary artery occlusion were investigated using an isolated in-situ dog heart model. The left anterior descending artery (LAD) was occluded for 60 minutes followed by 60 minutes of cardioplegic arrest and reperfusion after release of the coronary artery occlusion. Thirty one animals were divided into 3 groups according to the manner of cardioplegic arrest. The first group of animals (n=10) received multiple doses of cold St. Thomas' Hospital solution delivered antegradely through the aortic root. The second group of animals (n=11) received the same dose of the crystalloid solution delivered retrogradely through the coronary sinus. The third group of animals (n=10) received RCWBC through the coronary sinus. In the animals which were capable of supporting the working mode after reperfusion (8 hearts in each group), regional myocardial function in the occluded LAD distribution measured by sonomicrometer as well as global myocardial function evaluated by left-ventricular stroke-work index were not significantly improved during reperfusion by RCWBC. Corresponding to the functional data, myocardial pH in the occluded LAD distribution was not significantly increased by RCWBC. Although RCWBC maintained myocardial pH in the circumflex artery distribution at a significantly higher level than the other two groups of hearts undergoing cold crystalloid cardioplegia, RCWBC resulted in a substantial decline of myocardial pH in the right-ventricular free wall. These results suggest that RCWBC after 60 minutes of LAD occlusion may not provide a significant benefit in myocardial preservation compared to cold crystalloid cardioplegia delivered through either an antegrade or retrograde manner.

Independent regulation of sterol regulatory element-binding proteins 1 and 2 in hamster liver

Two sterol regulatory element-binding proteins (SREBPs, designated SREBP-1 and SREBP-2), each approximately 1150 amino acids in length, are attached to membranes of the endoplasmic reticulum and nuclear envelope in human and hamster tissue culture cells. In the absence of sterols, soluble fragments of approximately 470 amino acids are released from both proteins by proteolytic cleavage. The soluble fragments enter the nucleus, where they bind to sterol regulatory elements in the promoters of genes encoding the low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl CoA synthase, thereby activating transcription. Proteolytic processing of both SREBPs is blocked coordinately by sterol overloading and enhanced coordinately when sterols are depleted by treatment with an inhibitor of cholesterol synthesis. In contrast to these findings in cultured cells, the current data show that SREBP-1 and -2 are not coordinately regulated in hamster liver. In untreated animals the soluble fragment of SREBP-1, but not of SREBP-2, was detected by immunoblotting of a liver nuclear extract. Depletion of sterols by treatment with a bile acid-binding resin (colestipol) and a cholesterol synthesis inhibitor (mevinolin) led to a marked increase in the nuclear form of SREBP-2 and a reciprocal decline in the nuclear form of SREBP-1. These findings suggest that SREBP-1 is responsible for basal transcription of the low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl CoA synthase genes in hamster liver and that SREBP-2 is responsible for the increased transcription that follows sterol depletion with a bile acid-binding resin and a cholesterol synthesis inhibitor.

Vestibulocochlear defects and effects of deuterium oxide in mutant bustling (BUS) mice

Bustling mouse (BUS/Idr: bus) is a mutant mouse strain which exhibits bustling/hyperkinetic behavior and functional disorders related to the vestibulocochlear system such as rapid circling and loss of auditory startling response. In homozygous (bus/bus) mice this phenotype develops progressively after birth and has been shown from cross experiments to be inherited by a single autosomal recessive gene. Using light and electron microscopy, we examined the development of pathological changes in the inner ear of homozygous mice. Effects of deuterium oxide, which has been shown to influence vestibular function, on the abnormal behavior of homozygous mice of different ages were also examined. Pathological changes of the inner ear including impairment and/or loss of auditory hair cells, deformation and/or loss of the inner and outer tunnels of the organ of Corti, hypoplasia of the otoliths, and decrease in number of neurons of the spiral genglion were observed in the homozygous mice starting before the weaning stage and progressively thereafter, but not in the heterozygous mice. Although histological changes were also noted in the crista ampullaris and maculae, they were less evident than those in the cochlea at least until the mice were 6 weeks old. Administration of deuterated physiological saline (8-16 ml/kg, per os) tended to decrease the abnormal behavior of the homozygous mice, including rapid circling. These morphological and functional findings suggest that BUS mice may be a useful model for analysis of the pathogenesis of vestibulo-cochlear disorders.

Role of the LIM class homeodomain protein Xlim-1 in neural and muscle induction by the Spemann organizer in Xenopus

Like all known LIM class homeobox genes, Xlim-1 encodes a protein with two tandemly repeated cysteine-rich LIM domains upstream of the homeodomain. In Xenopus laevis, Xlim-1 is specifically expressed in the Spemann organizer, whose major functions include neural induction and dorsalization of ventral mesoderm. From RNA injection experiments we conclude here that: (1) the LIM domains behave as negative regulatory domains; (2) LIM domain mutants of Xlim-1 elicited neural differentiation in animal explants; (3) mutant, and to a lesser extent wild-type, Xlim-1 enhanced muscle formation after coinjection with Xbra; (4) both of these activities are mediated by extracellular signals as seen in combined explant experiments; (5) Xlim-1 mutants activated goosecoid (gsc) expression in animal explants, but not expression of noggin or follistatin; (6) mutant Xlim-1 elicited formation of partial secondary axes, and cooperated with gsc in notochord formation. Thus Xlim-1 has latent activities, implicating it in organizer functions.

Contribution of RGD sequence to neuronal migration in developing cerebral cortex

The RGD sequence (Arg-Gly-Asp) is known to bind integrins and the synthetic RGD tripeptide inhibits cell adhesion and migration of cultured neuronal cells. However, it is not known whether migration of neuronal precursors in vivo during the cortical histogenesis of the mammalian telencephalon depends on the RGD sequence. To examine this possibility, the RGD peptide was injected into the telencephalic vesicle of mouse embryos. A hypoplastic cortical plate was induced and histological analysis and BrdU-immunohistochemistry revealed that the RGD sequence is involved in neuronal migration and proliferation in the telencephalon during formation of the cortical plate.

[Two cases of complete transection of the thoracic aorta caused by blunt chest trauma]

Two patients with complete transection of the thoracic aorta, caused by blunt chest trauma, were survived after successful surgical repair. Only seven such cases are reported in the Japanese literature. The present cases were 52- and 28-year-old males injured in different accidents by rapid deceleration, both at collision with the rear of a parked trunk. The first case, on the fifth day of hospitalization, suddenly went into shock with severe thoracodorsal pain. The second case developed hemothorax soon after the accident. Both cases were diagnosed with angiography. The lesions were located in the upper portion of the descending aorta. The operations, performed on the 13th and 34th days after the respective accidents, combined median sternotomy with left thoracotomy through the 3rd intercostal space. The first case suffered complete transection of the aorta at the ductal ligament. In the second case, the intima and media of the descending aorta, at 8 cm below the branching of the left subclavian artery, were affected by complete transection. We operated with a V-A bypass of which cannulation was performed to right atrium and left femoral artery in the first case, and with an ascending aorta-left femoral artery bypass with a centrifugal pump in the second case. The lesions were repaired with 26 mm and 20 mm woven Dacron grafts, respectively. The patients have recovered sufficiently to do normal daily lives. In cases with circumferential transection of the thoracic aorta caused by blunt chest trauma, only those with pseudoaneurysm formation, who remain in a hemostatic state can be saved by surgery, We conclude that if the hemodynamic state is stable and blood pressure is strictly controlled in such cases, the elective operation can be performed.

Transgenic mouse model of hemifacial microsomia: cloning and characterization of insertional mutation region on chromosome 10

The 643 transgenic mouse line carries an autosomal dominant insertional mutation that results in hemifacial microsomia (HFM), including microtia and/or abnormal biting. In this paper, we characterize the transgene integration site in transgenic mice and preintegration site of wildtype mice. The locus, designated Hfm (hemifacial microsomia-associated locus), was mapped to chromosome 10, B1-3, by chromosome in situ hybridization. We cloned the transgene insertion site from the transgenic DNA library. By using the 5' and 3' flanking sequences, the preintegration region was isolated. The analysis of these regions showed that a deletion of at least 23 kb DNA occurred in association with the transgene integration. Evolutionarily conserved regions were detected within and beside the deleted region. The result of mating between hemizygotes suggests that the phenotype of the homozygote is lethality in the prenatal period. These results suggest that the Hfm locus is necessary for prenatal development and that this strain is a useful animal model for investigating the genetic predisposition to HFM in humans.

[A case report of emergency surgery for ruptured thoracic aortic aneurysm into the right thoracic cavity]

Rupture of aneurysm of descending thoracic aorta into the right thoracic cavity is an uncommon manifestation and, therefore, carries a high mortality rate. Sixty seven-year-old female was referred to our hospital due to ruptured aneurysm of descending thoracic aorta into the right thoracic cavity. Emergency operation was performed to replace the ruptured descending thoracic aorta through a left thoracotomy and to remove huge hematoma in the right thoracic cavity through a right thoracotomy. Post-operative chest radiograph showed well-expanded right lung which appears to prevent a serious respiratory complication. The patient recovered uneventfully after seven days of respiratory support.

Expression of the LIM class homeobox gene Xlim-1 in pronephros and CNS cell lineages of Xenopus embryos is affected by retinoic acid and exogastrulation

The LIM class homeobox gene Xlim-1 is expressed in Xenopus embryos in the lineages leading to (i) the notochord, (ii) the pronephros, and (iii) certain cells of the central nervous system (CNS). In its first expression phase, Xlim-1 mRNA arises in the Spemann organizer region, accumulates in prechordal mesoderm and notochord during gastrulation, and decays in these tissues during neurula stages except that it persists in the posterior tip of the notochord. In the second phase, expression in lateral mesoderm begins at late gastrula, and converges to the pronephros at tailbud stages. Expression in a central location of the neural plate also initiates at late gastrula, expands anteriorly and posteriorly, and becomes established in the lateral regions of the spinal cord and hindbrain at tailbud stages. Thus Xlim-1 expression precedes morphogenesis, suggesting that it may be involved in cell specification in these lineages. Enhancement of Xlim-1 expression by retinoic acid (RA) was first detectable in the dorsal mesoderm at initial gastrula. During gastrulation and early neurulation, RA strongly enhanced Xlim-1 expression in all three lineages and also expanded its expressing domains; this overexpression correlated well with RA phenotypes such as enlarged pronephros and hindbrain-like structure. Exogastrulation reduced Xlim-1 expression in the lateral mesoderm and ectoderm but not in the notochord, suggesting that the second phase of Xlim-1 expression requires mesoderm/ectoderm interactions. RA treatment of exogastrulae did not revert this reduction.

Crystallization and preliminary X-ray diffraction studies of curculin. A new type of sweet protein having taste-modifying action

A taste-modifying protein, curculin, has been crystallized by the vapor diffusion method using polyethylene glycol 400 as a precipitant. The crystals belong to orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions: a = 105 A, b = 271 A, c = 48.7 A. The crystals diffract X-rays to at least a resolution of 3.0 A and are suitable for X-ray crystallographic studies.

Microsurgical techniques in the genetic engineering of Mammalian embryos at the preimplantation stage

The genetic engineering of mammalian whole embryos has become one of the most popular and fruitful techniques in modern developmental biology, not only to investigate the normal development and pathogenesis of diseases but also to develop future gene-therapy applications for human genetic diseases. Although the rapid advancement of molecular biological techniques has created a theoretical basis for genetically engineering mammalian embryos, it has become practical only after the establishment of the culture system for mammalian embryos, which normally develop (hidden from the human eye) in the oviduct and the uterus, the improvement of optic instruments, and finally, the development and establishment of microsurgical techniques.

A novel aspect of thrombin in the tissue reaction following central nervous system injury

Thrombin and two different types of control solutions (buffer and albumin) were continuously infused into the rat caudoputamen by an osmotic minipump. Routine histological studies with immunohistochemistry using antibodies for BrdU, GFAP, vimentin and laminin were carried out to assess infiltration of inflammatory cells, formation of edema, cell proliferation, and reactivity of astrocytes and mesenchymal cells. The number of inflammatory cells, number of BrdU positive cells, area and number of vimentin positive astrocytes, and the area of GFAP-positive reactive astrocytes were quantitatively analyzed. In the thrombin group, pale tissue foci due to spongiosis were observed together with infiltration of inflammatory cells, proliferation of mesenchymal cells, and increase of vimentin positive astrocytes which was significantly different from the control groups. The results suggest that thrombin plays an important role in inflammation, brain edema and reactive gliosis following CNS injury.

Development of the lens in human embryos: a histochemical and ultrastructural study

The early development of the lens was examined, using 36 externally normal human embryos at Carnegie stages 13-23 (4 to 8 weeks of gestation). Twenty-two embryos were sectioned serially and stained with periodic acid-Schiff and a modified method of PAS. In 14 embryos, not only the differential distribution of glycogen but also the ultrastructural change in the developing lens, with special reference to junctional complexes, were examined electron microscopically. At stage 15, when the lens vesicle was formed, glycogen was observed in the cytoplasm of the lens epithelium, especially in the posterior lens epithelium. From stages 16 to 18, when the posterior lens epithelium was differentiated into the primary lens fibers and elongated toward the anterior lens epithelium, the amount of glycogen increased in the basal cytoplasm of the primary lens fiber, where the intracellular organelles, such as the tubular vesicles, mitochondria and multivesicular bodies, began to aggregate. At stage 20, when the lens cavity was obliterated, glycogen was also present in the anterior lens epithelium. At stage 21, as the formation of the secondary lens fibers proceeded, glycogen was noted in the secondary lens fibers in the equator region. These findings suggest that the distribution of glycogen is associated with the formation of the primary and secondary lens fibers. In addition, we provide additional information that a lot of glycogen is distributed in the region where many intracellular organelles aggregate in the embryonic lens vesicles.

Tyrosine kinase(s) regulate apoptosis and bcl-2 expression in a growth factor-dependent cell line

Apoptosis (programmed cell death) plays a critical role in many physiological processes, but the mechanism(s) which regulate apoptosis are poorly understood. We demonstrate that in a hematopoietic cell line, which can grow in either interleukin (IL)-2 or IL-3, both of these growth factors can increase bcl-2 mRNA levels and prevent apoptosis normally seen following growth factor withdrawal. Herbimycin A, a protein tyrosine kinase inhibitor, blocks the ability of IL-2 and IL-3 to up-regulate bcl-2 mRNA levels and induces apoptosis. Transfection of a bcl-2 expression vector not only prolongs survival following growth factor withdrawal but also confers resistance to the effect of herbimycin A. We conclude that herbimycin A-sensitive protein tyrosine kinases are involved in the regulation of apoptosis and bcl-2 expression, but these protein tyrosine kinases appear not to be required for the action of Bcl-2 since Bcl-2 can exert its growth survival effect even in the presence of herbimycin A.

Locus of control and implicit memory

Two experiments were conducted to investigate the influence of locus of control on implicit and explicit memory. We hypothesized that internals would rely on semantic processing, externals on perceptual processing. In Experiment 1, 80 college students studied 36 words and completed an implicit memory test in either a consistent or cross-modality condition. The results revealed that externals had higher priming scores than did internals, regardless of modality. In Experiment 2, 80 college students took either an implicit or explicit test. The results again revealed that externals showed higher priming scores than internals. The higher priming scores exhibited by the externals do not necessarily mean that they are more perceptually oriented than the internals are.

Regulatory interactions during embryogenesis in Xenopus laevis

During amphibian embryogenesis, axis definition and the specification of the mesoderm and neural plate depend on cell interactions. These interactions are mediated by peptide growth factors and other diffusible molecules including retinoic acid (RA). Several genes encoding transcription factors are known to be immediate early or delayed early responses to the action of growth factors and retinoids in the embryo. By the criterion of cycloheximide (CHX) resistance, goosecoid (gsc), Xlim-1, Xbra, Mix.1, XFKH1/pintallavis/XFD1, and Xnot are immediate early response genes in mesoderm/induction. Among these, gsc, Xnot and XFKH1 are superinduced by CHX, suggesting that their regulation depends in part on rapid turnover of the mRNA. RA is known to induce Xlim-1 in Xenopus embryos and to lead to anterior malformations. We show that 9-cis RA, the ligand of the RXR receptor class, is more effective than all-trans RA in generating these biological effects.

Expression of LIM class homeobox gene Xlim-3 in Xenopus development is limited to neural and neuroendocrine tissues

The Xenopus LIM class homeobox gene Xlim-3 was identified initially as a fragment isolated by polymerase chain reaction cloning with an embryonic cDNA library as template (Taira et al., 1992, Genes Dev. 6, 356-366). cDNA clones representing most of the Xlim-3 mRNA were isolated from an adult brain library. The predicted Xlim-3 protein contains two copies of the LIM domain, a homeodomain, and a C-terminal region rich in proline, glycine, and serine. RNA blot hybridization showed that Xlim-3 mRNA is detected in dorsal regions at neural tube and tailbud stages and in adults predominantly in the pituitary gland and weakly in the eye and brain. Whole mount in situ hybridization revealed that Xlim-3 mRNA is first detectable at the neural plate stage in the stomodeal-hypophyseal (pituitary) anlage and in the neural plate where labeled cells were found adjacent to the forming floor plate. In situ hybridization analysis on serial sections at later stages showed that embryonic Xlim-3 expression persists in the pituitary and pineal, as well as in some cells of the retina, hindbrain, and spinal cord. In the retina, Xlim-3 mRNA was only detected in a distinct sublamina of the inner nuclear layer, but not in dividing cells of ciliary margin. This discrete manner of Xlim-3 expression, especially persistent expression in the pituitary (before morphogenesis of the gland to adult), supports a role in the specification and maintenance of differentiation of distinct neuronal and neuroendocrine tissues.

Regulation of apolipoprotein B production and secretion in response to the change of intracellular cholesteryl ester contents in rabbit hepatocytes

In the present study, we investigated the mechanisms that regulate apolipoprotein B-100 (apoB) secretion in response to the change of intracellular cholesteryl ester contents by adding low density lipoprotein (LDL) and an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase (pravastatin) in rabbit hepatocyte culture system. LDL caused a significant dose-dependent increase in apoB secretion. On the other hand, the addition of pravastatin decreased apoB secretion significantly. LDL caused a dose-dependent increase in cellular cholesteryl ester, while cellular cholesteryl ester was decreased by pravastatin significantly. Therefore, these results indicate that the change of apoB secretion was in parallel with the change of cellular cholesteryl ester contents. Cellular contents of free cholesterol, triglyceride, and phospholipid did not change. To investigate intracellular degradation of apoB prior to secretion, pulse-chase experiments were performed. It was shown that the addition of pravastatin accelerated intracellular degradation of apoB, while LDL slowed the apoB intracellular degradation rate. We also investigated whether the change of cellular cholesteryl ester could affect the apoB mRNA level. Northern blot analysis and solution hybridization RNase protection assay demonstrated that neither LDL nor pravastatin caused a significant change in cellular apoB mRNA level. We conclude that intracellular cholesteryl ester contents play a critical role in apoB secretion, and the intracellular apoB degradation rate could be the main mechanism that regulates apoB secretion in response to the change of intracellular cholesteryl ester level.

[Chloride channels in cardiac muscle]

This section describes properties, signal transduction pathways for activation and the physiological roles of cardiac Cl- channels. Recent application of patch clamp technics have revealed that a wide variety of Cl- channels are present in cardiac cells, which are regulated by different cellular stimuli, such as alpha 1- or beta-adrenoceptor stimulation, ATP, adenosine and cell swelling. When these channels are activated, Cl- is transported ECl-dependently in both inward and outward directions, affecting the action potential durations and/or resting potentials. Analysis of cardiac Cl- channel mechanisms yields new aspects for understanding pathophysiological bases of heart diseases or arrests such as arrhythmia.

A novel family of retrotransposon-like elements in Xenopus laevis with a transcript inducible by two growth factors

A cDNA clone named 1A11 was isolated in a screen for genes that are activated by both mesoderm inducing factors FGF and activin in animal explants of Xenopus laevis embryos. In undisturbed embryos, 1A11 is expressed during the gastrula stage in the entire marginal zone where mesoderm originates, and later in the somites, the tailbud, and at much lower levels in lateral mesoderm. The 1A11 sequence of 4.5 Kb has a 220 bp repeat at its ends, indicative of a retrotransposon-like structure. A long open reading frame encodes a predicted protein with only short homologies to the gag and protease regions of retroviruses and retrotransposons. Multiple copies of 1A11-related sequences were found in the Xenopus genome, constituting solo LTRs (long terminal repeats) of 1267 bp, and unique region copies (i.e., sequences internal to the repeats in the cDNA). Inverted repeats of 5 bp and apparent target site duplications of 5 bp surround the sequenced solo LTR. Thus, 1A11 is a new retrotransposon-like element in Xenopus laevis.

Ultrastructure of the developing stomach in human embryos

Ultrastructural development of the stomach was studied by light, scanning electron and transmission electron microscopy, using 19 human embryos at Carnegie stages from 14 to 23 (6.8-28.0 mm in crown-rump length, 5 to 8 weeks of gestation). The precise time of appearance of differentiated characteristic structures was examined electron microscopically. The first gastric pit, with radially arranged epithelial cells beneath which the basement membrane bulged into the mesenchyme, was observed on the lesser curvature at stage 22. Although the mesenchymal condensation which would develop into the inner circular muscle layer appeared at stage 18 onward, cytoplasmic myofibrils were not observed until stage 22. Nerve fibers were first observed at stage 16, and at later stages they gathered into bundles to form a nerve plexus external to the developing inner circular muscle layer. On the basis of accurate timing of the appearance and the mode of development of these structures, possible relations between developing gastric layers were discussed. Histocytochemically, glycogen or other carbohydrates were demonstrated in the cytoplasm of the gastric epithelium throughout the stages examined. These carbohydrates were localized mainly in vacuole-like spaces in the basal part of the epithelial cells. This subcellular localization, and the amount of carbohydrate, did not change significantly during the observed embryonic period. In the serosa, carbohydrates were not detected at stages 14 and 15, but observed consistently within the vacuoles in the cytoplasm from stage 17 onward. No other layer of the embryonic stomach had detectable carbohydrates.(ABSTRACT TRUNCATED AT 250 WORDS)

99mTc-HMDP accumulation in a phyllodes tumor of the breast, a case report

In a patient with breast tumor, 99mTc-HMDP accumulation in the tumor was recognized in evaluating bone metastasis. Surgery and histopathology revealed that the tumor was a phyllodes tumor. This scintigraphic finding was thought to be rare and phyllodes tumor should be included in differential diagnosis when 99mTc-HMDP accumulation in the breast was recognized.

Differential induction of regulatory genes during mesoderm formation in Xenopus laevis embryos

Mesoderm development in Xenopus laevis depends on inductive cell interactions mediated by diffusible molecules. The mesoderm inducer activin is capable of redirecting the development of animal explants both morphologically and biochemically. We have studied the induction of four regulatory genes, Mix. 1, goosecoid (gsc), Xlim-1, and Xbra in such explants by activin, and the influence of other factors on this induction. Activin induction of gsc is strongly enhanced by dorsalization of the embryo by LiCl, while expression of the other genes is only slightly enhanced. The protein synthesis inhibitor cycloheximide (CHX) inhibits the activin-dependent induction of Xbra partially, while induction of Mix. 1 and Xlim-1 is essentially unaffected. In contrast, gsc shows strong superinduction in the presence of activin and CHX, and can be induced in animal explants by CHX alone. Induction and superinduction by CHX have previously been observed for immediate early genes in a variety of systems, notably for the activation of c-fos expression by serum stimulation, but have not been reported in early amphibian embryos.

Different patterns of protein kinase C redistribution mediated by alpha 1-adrenoceptor stimulation and phorbol ester in rat isolated left ventricular papillary muscle

1. In rat left ventricular papillary muscle, phenylephrine, an alpha 1-adrenoceptor agonist, had a staurosporine-sensitive positive inotropic effect and increased the particulate-associated protein kinase C (PKC) activity without significant changes in total PKC activity or in cytosolic Ca2+/phospholipid-independent kinase (PKI) activity. 2. A PKC stimulant, phorbol 12,13-dibutyrate (PDBu), decreased contractility and slightly increased PKC activity in the particulate fractions, with a marked decrease and increase in total PKC and PKI activities, respectively. 3. The PDBu-induced negative inotropic response was attenuated by two protease inhibitors, leupeptine and a microbial peptide isolated from Aspergillus japonicus (E-64), which are known to inhibit the conversion of particulate-associated PKC to PKI. 4. Such differences in the patterns of PKC redistribution, i.e. marked increases in particulate PKC and cytosolic PKI activities caused by phenylephrine and PDBu, respectively, may account for the opposite inotropic effects of PKC stimulation by an alpha 1-agonist and a phorbol ester.

Supra-neuroectodermal cells and fibers on the primary nasal cavity and in the fourth ventricle of mouse and human embryos: scanning and transmission electron microscopic studies

Neuroectoderm-derived epithelia of the primary nasal cavity and the fourth ventricular floor and roof were observed by scanning (SEM) and transmission electron microscopy (TEM) and SEM-TEM correlative views in mouse embryos of 9th to 13th days of gestation, and in 38 externally normal human embryos ranging at Carnegie stages from 13 to 18 (about 5 to 7 weeks of gestation). Smooth-surfaced spindle-shaped cells with one or more cytoplasmic processes and cord-like cytoplasmic structures were observed by SEM on the wall of the primary nasal cavity of both species. They had morphological features similar to those of neuronal type 1 supraependymal (SE) cells and SE fibers on the floor and roof of the fourth ventricle in both species. Type 1 SE cells, SE fibers, and corresponding structures in the primary nasal cavity were localized in relation to the underlying developing nerve and vascular systems. Furthermore, their processes and fibers ran roughly parallel to these underlying structures and they penetrated the epithelial layer at the ends, suggesting a connection with underlying structures. From TEM and SEM-TEM correlative observations, SE fibers in the fourth ventricle and cord-like structures in the primary nasal cavity, both with a larger diameter, were deduced as single axon-like processes or bundles of processes. Those fibers and cord-like structures of smaller diameters were interpreted as elongated telophase bridges; both contained parallel packed microtubules and connected distant cells. Since these processes and fibers were generally longer and became fewer at later developmental stages, they appeared to be transient neuronal structures. They may play a development-related role in such morphogenetic cell movements as in the developing nerve and vascular systems in the epithelial and/or subepithelial layers, but not as direct rudiments of adult nerve tissues.

Age differences in perception of risk

Age differences in perception of risk and the likelihood of disregarding warning signs were examined. A total of 358 adults, between 18 and 85 years old, were asked to rate 12 warning labels with respect to (a) how risky it would be to ignore the warning, (b) how likely it was that they would disregard the warning, and (c) how familiar they were with the labels. The older groups indicated higher risk in ignoring the signs than did the younger group. The older subjects were also less willing to disregard the signs than the younger subjects.

Interleukin (IL)-2 and IL-3 induce distinct but overlapping responses in murine IL-3-dependent 32D cells transduced with human IL-2 receptor beta chain: involvement of tyrosine kinase(s) other than p56lck

We have established IL-3-dependent 32D myeloid progenitor cells stably expressing the human IL-2 receptor beta chain (IL-2R beta). Whereas parental 32D cells proliferated only in response to IL-3, the transduced cells also proliferated in response to IL-2. Transduced cells expressed high- and intermediate-affinity IL-2Rs, resulting from expression of human IL-2R beta and murine IL-2R alpha chain (IL-2R alpha). IL-2 induced phenotypic changes not induced by IL-3, including the upregulated expression of endogenous murine IL-2R alpha and IL-2R beta and an increase in cell size. Therefore, the transduced IL-2R beta was not merely coupling with the IL-3 signaling pathway. IL-3 augmented several IL-2-induced responses including the up-regulation of IL-2R alpha. Both IL-2- and IL-3-induced proliferation and IL-2 induced IL-2R alpha expression were inhibited by the tyrosine kinase inhibitor herbimycin A. Thus, both IL-2- and IL-3-mediated effects required tyrosine kinase activity. The identity of the tyrosine kinase(s) mediating the IL-2 signals in these cells is not known but cannot be p56lck, a tyrosine kinase found in T cells, since 32D-IL-2R beta cells do not express p56lck.

Interleukin (IL)-2 activation of p21ras in murine myeloid cells transfected with human IL-2 receptor beta chain

The T cell growth factor interleukin-2 (IL-2) induces p21ras activation in T lymphocytes. To determine whether the IL-2 receptor (IL-2R) can regulate p21ras when expressed in a non-T cell environment we have examined the ability of IL-2 to activate p21ras in 32D murine myeloid progenitor cells transduced with human IL-2R beta chains. These cells are denoted beta 53 cells. 32D cells normally proliferate in response to IL-3 but the expression of the IL-2R beta chain confers IL-2 responsiveness to the cells. Our data show that IL-3 is able to activate p21ras in the parental 32D cells and both IL-2 and IL-3 can stimulate p21ras in the IL-2R-expressing beta 53 clone of 32D. In T lymphocytes, activation of protein kinase C (PKC) with phorbol esters is sufficient to stimulate p21ras. However, in 32D and beta 53 cells activation of PKC with phorbol esters does not result in p21ras activation even though these cells express functional PKC. It appears, therefore, that a PKC-mediated pathway for p21ras regulation exists in T lymphocytes but not in 32D cells. The IL-2R can couple to p21ras independently of the concomitant presence of the PKC pathway for p21ras regulation. These data imply that multiple intracellular mechanisms may exist to regulate p21ras and that cells of different lineages may differ with regard to p21ras regulation.

[Relationship between venous invasion and hematogenous metastasis in the colorectal cancer patients]

We investigated the correlation between venous invasion and hematogenous metastasis. In thirteen patients with colorectal carcinoma, depth of invasion (ss.s or a1.a2) was the same. Four cases had hepatic metastasis at operation (group A), 3 cases were identified with hematogenous recurrence after operation (group B), and 6 cases were disease free over 10 years after operation (group C). Specimens were all step-sectioned and serial sections were stained both with HE and EM. Results were as follows. 1. Venous invasion was found in all cases and average rates of venous invasion (ARVI) of groups A and B were higher than that of group C (A; 7.8%, B; 6.3%, C; 2.1%, p less than 0.05). 2. In ss.s layer, ARVI of group A and B were higher than that of group C (A; 6.1%, B; 6.2%, C; 1.5%, p less than 0.05). 3. Rates of venous invasion to larger veins (diameter greater than 200 microns) were higher in group A than in others (A; 53.5%, B; 25.6%, C; 7.9%, p less than 0.05), and those to the middle-sized veins (diameter; 50-200 microns) were higher in group B than in others. These facts suggest that cancer invasion to the veins located in ss.s (a1.a2) layer or ranged in diameter over 200 microns relates to hematogenous metastasis.

Effect of cardioplegic preservation on intracellular calcium transients

Intracellular Ca2+ ([Ca2+]i) plays a pivotal role in the regulation of cardiac function. We investigated the effect of cardioplegic preservation on [Ca2+]i transients in the isolated and perfused guinea pig heart loaded with a fluorescent Ca2+ indicator (fura-2). The measurements of [Ca2+]i transients and isovolumetric left ventricular pressure revealed that [Ca2+]i transients and mechanical responses to [Ca2+]i were markedly altered during 15 minutes of normothermic global ischemia and after reperfusion. First, [Ca2+]i transients remained during ischemia without generation of active force of contraction. Such a manifestation of depressed sensitivity of the myofilaments to Ca2+ persisted for the first 5 minutes after reperfusion. Second, the amplitude of [Ca2+]i was diminished during ischemia and reperfusion. Third, diastolic [Ca2+]i was increased during ischemia and especially at the onset of reperfusion. Bolus infusion of cold St. Thomas' Hospital solution abolished [Ca2+]i transients and left ventricular pressure development at an end-diastolic level. Moreover, improved recovery of left ventricular function during reperfusion afforded by the hypothermic cardioplegia was intimately related to its ability to modulate impaired [Ca2+]i transients and mechanical responses to [Ca2+]i; improvement of systolic left ventricular function appears to be produced by restoration of Ca2+ sensitivity of the myofilaments and the amplitude of [Ca2+]i transients, whereas better diastolic compliance of the left ventricle is ascribed to significantly lower diastolic [Ca2+]i. These results may provide new insight into the mechanism of cardioplegic preservation on the basis of [Ca2+]i transients.

Diabetic environment and genetic predisposition as causes of congenital malformations in NOD mouse embryos

Congenital malformations such as neural tube defects and a kinky or waved vertebral column were observed at higher incidence in embryos from nonobese diabetic (NOD) female mice with overt diabetes (NOD-D; 40.3%, P less than 0.005) or without overt diabetes (NOD-N; 8.4%, P less than 0.05) than in control Institute of Cancer Research (ICR) mouse embryos (1%) at day 13 of gestation. In vivo and in vitro preimplantation development of NOD-N, NOD-D, and ICR embryos did not differ in rate of development, size, or morphology. Embryos cultured from one-cell to early blastocyst stage were mutually transferred to uterine horns of pseudopregnant females between NOD-D and ICR mice and examined at day 13 of gestation. There were significant decreases in ratios of implantation and of viable embryos in ICR embryos transferred to NOD-D recipients (52%, P less than 0.001 and 14%, P less than 0.001, respectively) compared with those ratios in ICR embryos transferred to ICR uteri (79.2 and 56.2%) or those in NOD-D embryos transferred to ICR uteri (70.3 and 33.1%). Furthermore, 18 of 45 viable ICR embryos transferred to NOD-D dams had malformations, whereas there were no malformations in 73 viable ICR embryos transferred to ICR recipients, suggesting deleterious effects of maternal diabetic environment to embryos. On the other hand, 8 of 58 viable NOD-D embryos that were cultured in vitro and transferred to ICR uteri had malformations such as neural tube defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of amiloride and an analogue on ventricular arrhythmias, contracture and cellular injury during reperfusion in isolated and perfused guinea pig heart

The present study was designed to examine whether activation of Na+/H+ exchange and subsequent massive Ca2+ influx via Na+/Ca2+ exchange are involved in the pathogenesis of myocardial reperfusion injury. We tested the effects of 1 mM amiloride, which is known to inhibit both Na+/H+ and Na+/Ca2+ exchange, and 3 microM 5-(N-ethyl-N-isopropyl) amiloride (EIPA), which is known to act as a specific inhibitor against Na+/H+ exchange, on the incidence of ventricular arrhythmias, isovolumic left ventricular function and creatine kinase (CK) release during reperfusion after 15 or 30 min of global ischemia in the isolated and perfused guinea pig heart. Treatment of a normally perfused heart with amiloride decreased heart rate significantly and tended to increase coronary flow and left ventricular developed pressure (LVDP), whereas treatment with EIPA decreased all of these 3 measurements significantly. Treatment with amiloride or EIPA for 15 min before ischemia, and during reperfusion after 15 min of ischemia, under electrical pacing at 240 rpm to eliminate a negative chronotropic effect abolished ventricular tachycardia (VT) and ventricular fibrillation (VF) during reperfusion associated with highly significant inhibition of increases in left ventricular end-diastolic pressure (LVEDP) and CK release. Amiloride or EIPA pretreatment also inhibited the incidence of VF and increases in LVEDP and CK release significantly during reperfusion after 30 min of ischemia. However, amiloride was more effective in preventing these events than EIPA. The treatment with amiloride or EIPA only during reperfusion after 15 or 30 min of ischemia also decreased the incidence of VF and inhibited the increases in LVEDP and CK release significantly, though less effectively than the pretreatment modality. These results suggest that EIPA prevents ventricular arrhythmias, contracture and myocardial cellular injury during reperfusion after 15 min of ischemia by inhibiting Na+/H+ exchange, while amiloride exerts more powerful protection against these events than EIPA during reperfusion after 30 min of ischemia by inhibiting both Na+/H+ and Na+/Ca2+ exchange.

Host recognition by toxigenic plant pathogens

Certain fungal pathogens release host-selective (or host-specific) toxins (HST) as a host recognition factor during spore germination at the infection site on plants. Prior to penetration of the pathogen into its host, the released toxin specifically binds to a putative receptor on the host cells and initiates signaling mechanisms leading to pleiotropic effects on cells. Of these, the crucial one negates the general and inducible defense reactions of the cells. This is accomplished by a signal from the HST, which is transduced through a path way at or near the step of plasma membrane modulation, which is directly or indirectly triggered by the HST. This mechanism operates even though the toxin may affect mitochondria or chloroplasts as the primary target organelle. The fungal spore is able to penetrate the so-called 'narcotized cell' and completes the initial colonization of the host. The host recognition process may take place without necessitating host cell death, even in the case of perthophytic parasites. At the molecular level, HST-mediated recognition of the host by a pathogen requires strict stereochemical precision like a lock and key.

Histochemically demonstrable phosphotyrosine protein phosphatase in the rat hippocampal formation

Using o-phospho-L-tyrosine as substrate, a possible localization of phosphotyrosine protein phosphatase (PTPPase) activity was histochemically demonstrated in the rat hippocampal formation. The PTPPase activity was found in almost all layers of the hippocampal formation, with a high activity in the stratum moleculare. The activity was inhibited by vanadate and molybdate, but not by NaF and Zn2+. The activity was localized in the dendritic cytoplasm, particularly on the postsynaptic density, of hippocampal neurons.

Surface condition of primary teeth after approximal grinding and polishing

Mesiodistal reduction of primary teeth is necessary in cases with mild or moderate primary crowding, in patients treated with Fränkel appliance type I or II or in those who need to keep a primary molar as long as possible due to congenitally missing premolars. In order to minimize the risks of periodontal destruction and caries, the tooth surface should be polished after grinding. A technique for stripping permanent teeth, recently proven successful in achieving smoother enamel than untreated tooth surfaces, was slightly varied and applied to primary teeth. By means of scanning electron micrographs, it could be shown that application of this technique produces smooth surfaces on primary teeth as well. The procedure is described in detail and cases in which it should be used are presented.

Chromosome analysis of postimplantation stage embryos for studying possible causes of developmental abnormalities in nonobese diabetic mice

The chromosomes of postimplantation stage embryos of nonobese diabetic (NOD) mice were analyzed to investigate the causal mechanism of congenital anomalies in diabetic pregnancies. Postimplantation stage embryos (day 12 of gestation) in diabetic (NOD-DM) and nondiabetic (NOD-N) NOD mice had either a high or low incidence of chromosomal abnormalities. A large majority of externally normal embryos from NOD-DM and NOD-N mice had low incidences. A high incidence of chromosomal abnormalities was found in externally abnormal embryos of NOD-DM and NOD-N mice, and in a smaller number of externally normal NOD-N and NOD-DM embryos. No control ICR embryo manifested a high incidence of chromosomal abnormalities. In the NOD-DM embryos, the chromosomes appeared to be influenced by long-term maternal diabetic conditions, while high incidences of chromosomal abnormalities in the NOD-N embryos suggested a probable cause by other factor(s) (e.g. a genetic predisposition) or by a very mild diabetic condition because the NOD-N mice were prediabetic.

Effects of inhibitors of protein kinase C and Na+/H+ exchange on alpha 1-adrenoceptor-mediated inotropic responses in the rat left ventricular papillary muscle

1. Alpha 1-adrenoceptor stimulation of rat left ventricular papillary muscle produced a triphasic inotropic response: an initial transient positive inotropic effect (PIE) followed by a transient negative inotropic effect (NIE) and a sustained PIE. 2. The protein kinase C inhibitor, staurosporine, at concentrations ranging from 30 nM to 100 nM inhibited the sustained PIE, but had no significant effect on the transient PIE and NIE. 3. H-7, 1-(5-isoquinoline sulphonyl)-2-methylpiperazine, a less specific inhibitor of protein kinase C than staurosporine, at a concentration of 100 microM inhibited both the transient NIE and the sustained PIE without affecting the transient PIE. 4. Amiloride, an inhibitor of Na+/H+ exchange, at concentrations ranging from 0.1 mM to 1 mM inhibited the sustained PIE and, at higher concentrations, also inhibited the transient NIE. 5. An amiloride analogue, 5-(N-methyl-N-isobutyl)amiloride (MIBA), inhibited only the sustained PIE with an IC50 of 0.3 microM which is approximately two orders of magnitude lower than amiloride. 6. The receptor-linked stimulation of Na+/H+ exchange through protein kinase C activation may be a mechanism for alpha 1-adrenoceptor-mediated sustained PIE.

Human interleukin 2 receptor beta-chain gene: chromosomal localization and identification of 5' regulatory sequences

Interleukin 2 (IL-2) binds to and stimulates activated T cells through high-affinity IL-2 receptors (IL-2Rs). Such receptors represent a complex consisting of at least two proteins, the 55-kDa IL-2R alpha chain and the 70-kDa IL-2R beta chain. The low-affinity, IL-2R alpha chain cannot by itself transduce a mitogenic signal, whereas IL-2 stimulates resting lymphocytes through the intermediate-affinity, IL-2R beta receptor. We report here identification of the genomic locus for IL-2R beta. The exons are contained on four EcoRI fragments of 1.1, 9.2, 7.2, and 13.7 kilobases. The 1.1-kilobase EcoRI fragment lies at the 5'-most end of the genomic locus and contains promoter sequences. The promoter contains no TATA box-like elements but does contain the d(GT)n class of middle repetitive elements, which may play an interesting regulatory role. The IL-2R beta gene is localized to chromosome 22q11.2-q12, a region that is the locus for several lymphoid neoplasias.

Role of a nonsteroidal anti-inflammatory agent, ibuprofen, in coronary revascularization after acute myocardial infarction

The efficacy of using a nonsteroidal anti-inflammatory agent such as ibuprofen for the salvage of ischemic and reperfused myocardium was investigated by examining its ability to improve global and regional functions as well as to preserve high-energy phosphate compounds and inhibit creatine kinase release from an isolated in-situ pig heart subjected to 1 h of normothermic regional ischemia followed by 1 h of global hypothermic arrest and 1 h of normothermic reperfusion. Preperfusion of the heart for 15 min prior to ischemic insult with 50 microM ibuprofen failed to mitigate the myocardial reperfusion injury. Ibuprofen, however, functioned as an anti-inflammatory agent, as judged by its ability to inhibit the influx of indium-111-labeled polymorphonuclear leukocytes and chromium-51 (51Cr)-labeled platelets into the ischemic and reperfused heart. It also blocked the cyclooxygenase pathway, as evidenced by the significant reduction of 6-keto-prostaglandin F1 alpha and thromboxane B2 concentrations in the perfusate. Inhibition of cyclooxygenase resulted in increased accumulation of nonesterified fatty acids, particularly arachidonic acid, in the heart. These results suggest that although ibuprofen can inhibit polymorphonuclear leukocyte and platelet influx into the ischemic and reperfused heart, it causes further damage to the already ischemic heart by reducing prostacyclin concentration and increasing free fatty acids in the heart.

[The experimental study on long-term cardiac preservation: the efficacy of low-flow continuous perfusion with fluorocarbon]

We compared the effect of simple immersion and continuous perfusion on long-term cardiac preservation, and evaluated the effectiveness of perfusion with oxygenated fluorocarbon solution. The isolated rabbit hearts were preserved for 24 hours at 4 degrees C using the following five preservation techniques: (1) simple immersion with Collins M solution (Group I), (2) perfusion with oxygenated Collins M solution at a flow rate of 10 ml/hr (Group II), (3) perfusion with the same solution as in Group II at a flow rate of 20 ml/hr (Group III), (4) perfusion with oxygenated Collins M solution containing 10% fluorocarbon at a flow rate of 10 ml/hr (Group IV), (5) perfusion with the same solution as in Group IV at a flow rate of 20 ml/hr (Group V). The hearts of Group I showed a significant decrease of myocardial ATP and an increase of myocardial lactate during preservation compared to the hearts of perfusion groups. Assessment of isovolumic left ventricular function following 24-hour preservation using a support animal showed a significant decrease of Max dp/dt and increase of end-diastolic pressure in the hearts of Group I. Perfusion with fluorocarbon (Group IV and V) significantly increased oxygen consumption compared to Group II and III in association with minimum accumulation of myocardial lactate, indicating that aerobic metabolism during preservation is better maintained in the fluorocarbon-perfused hearts. Moreover, CPK release and myocardial water gain during preservation were significantly less, and left ventricular function following preservation was significantly better in these hearts. Increasing the flow rate from 10 ml/hr to 20 ml/hr resulted in sustained increase in perfusion pressure (1.80 +/- 0.53 to 3.70 +/- 0.34 mmHg) and myocardial water content (79.2 +/- 0.4 to 87.2 +/- 0.3%) during preservation in the hearts of Group III, but it did not further improve left ventricular function despite significant enhancement of myocardial oxygen uptake in both Group III and V. These results suggest that hypothermic low-flow continuous perfusion with oxygenated Collins M solution is superior to simple immersion with the same solution for long-term cardiac preservation, and that the addition of fluorocarbon to the perfusate enhances the efficacy of such a perfusion.

Effect of calcium overload on the phosphoinositide breakdown in the rat left ventricular papillary muscle

We investigated the effect of Ca2+ overload on the phospholipase C-catalyzed hydrolysis of phosphoinositides in the rat left ventricular papillary muscle. Ca2+ overload on the papillary muscle was induced by treatment with 0.3 mM ouabain in Ca2+-containing medium following either Ca2+-containing or Ca2+-free superfusion. The phosphoinositide breakdown was evaluated by determining accumulations of [3H]inositol phosphates ([3H]IPs) in the tissues prelabeled with [3H]inositol. Ca2+ repletion following Ca2+-free superfusion resulted in a rapid but small increase in resting tension that was not followed by contracture, nor was it associated with a significant increase in [3H]IPs accumulations. Treatment with ouabain following Ca2+-containing superfusion increased resting tension after a lag period of several minutes and produced contracture associated with an increase in [3H]IPs accumulations. The ouabain induced increases in resting tension, and accumulations of [3H]IPs were significantly potentiated by prior Ca2+-free superfusion instead of Ca2+-containing superfusion. There was a significant positive correlation between increases in resting tension and the phosphoinositide breakdown. The increased resting tension and the accumulations of [3H]IPs were not antagonized by treatments with prazosin plus atropine or indomethacin, but were abolished by superfusion with Ca2+-free buffer solution. Although the enhanced phospholipase C-catalyzed hydrolysis of phosphoinositides appears to be a consequence rather than a cause of increased intracellular Ca2+, such a biochemical change may provoke a positive feedback mechanism to develop the muscle contracture through the putative intracellular messenger action of inositol triphosphate and diacylglycerol.

Intracerebroventricular injection of ethacrynic acid induces status epilepticus

The intracerebroventricular (i.c.v.) injection of ethacrynic acid to mice at a dose of more than 25 micrograms induced repeated tonic-clonic convulsions with subsequent death. Ethacrynic acid was more potent than other loop diuretics such as furosemide and bumetanide. Diazepam and 2-amino-5-phosphonovaleric acid notably reduced both the incidence of convulsion and the lethality seen after ethacrynic acid administration. Both phenobarbital and ketamine suppressed the incidence of convulsions but not the lethality. Without effects on the incidence of convulsions or lethality, dextromethorphan prolonged, while phenytoin or atropine shortened, the time to the onset of convulsion. Neither ethosuximide, carbamazepine, nor muscimol had a significant effect on the responses to ethacrynic acid. The present findings indicate that i.c.v. injected ethacrynic acid shows strong convulsive activity, probably due to impairment of Cl- transport processes, concomitant with enhancement of excitatory amino acid activity in the brain.