LIMK-1 and LIMK-2, two members of a LIM motif-containing protein kinase family

We previously isolated human cDNA encoding LIM-kinase (LIMK), a putative protein kinase which contains two repeats of the LIM motif at the N-terminus and a protein kinase consensus sequence at the C-terminus. Using as a probe a cDNA fragment of human LIMK, we isolated from a rat brain cDNA library cDNA clones encoding two distinct protein kinases (termed LIMK-1 and LIMK-2) related to human LIMK. LIMK-1 shares with human LIMK 95% of the total 647 amino acids and is probably a rat equivalent of human LIMK. LIMK-2 has an overall sequence and a domain structure similar to that of human LIMK and rat LIMK-1, but overall identity is 50-51% at the amino acid level. Like human LIMK, the protein kinase domains of rat LIMK-1 and -2 contain a characteristic sequence DLNSHN in subdomain VIB and a highly basic insert between subdomain VII and VIII. LIMK-1 and -2 are therefore closely related but distinct members of a novel LIM-containing protein kinase subfamily. Several forms of LIMK-2 transcripts encoding proteins that are N-terminally modified and/or C-terminally truncated are generated by alternative splicing or alternative initiation. Northern blot analysis revealed the expression of LIMK-1 mRNA predominantly in the brain and the expression of LIMK-2 mRNA in various tissues in the rat. Antibody raised against LIMK-1 specifically immunoprecipitated and identified in Rat2 fibroblast cells a 72 kDa protein, which has no detectable autophosphorylating activity but is capable of phosphorylating serine and threonine residues of myelin basic protein, by in vitro kinase reaction. As the LIMK family kinases have unique structural features, they are likely to have specific functions in previously uncharacterized signaling pathways.

Antigen receptor-initiated growth inhibition is blocked in CD45-loss variants of a mature B lymphoma, with limited effects on apoptosis

Role of CD45 in B cell antigen receptor (BcR)-mediated signaling events in mature B cells was examined using BAL-17 and its CD45-negative clones. In the CD45-negative clones, BcR stimulation induced tyrosine phosphorylation almost identical to the parental cells, with a few exceptions of reduced phosphorylation, especially of a protein of about 60 kDa. BcR-induced calcium responses were reduced in the CD45-negative clones, but the kinetics were similar to the parent. BcR stimulation led to growth inhibition in the parental cells, but signals for growth inhibition were completely blocked in the CD45-negative clones. Interestingly, the same stimulation induced low, but significant levels of apoptosis both in the parent and in the CD45-negative clones. Thus, in mature BAL-17 cells, CD45 subtly mediate early signaling events (tyrosine phosphorylation and Ca2+ mobilization), and is absolutely required for the signaling pathway leading to growth regulation, but has limited effects on apoptosis.

[Angioscopic observation of the ruptured plaque cap in a patient with acute myocardial infarction with particular reference to the mechanism of plaque rupture]

A 45-year-old man was admitted with the diagnosis of acute inferior myocardial infarction. After successful thrombolytic therapy, coronary angiography showed TIMI grade 3 flow with the filling defect and haziness on the infarct-related coronary segment. Repeat coronary angiography and coronary angioscopy were performed on the 28th hospital day. Coronary angiography showed 50% stenosis of the luminal diameter of the right coronary artery. Coronary angioscopy showed a white plaque with ruptured cap which occupied one third of the circumferential coronary artery. The torn ends of the cap were longitudinal, and projected into the lumen during the cardiac cycle. Plaque rupture and thrombus formation are important in the pathogenesis of acute coronary syndromes, although the mechanism of plaque rupture is still controversial. The present angioscopic findings seem to support the concept that circumferential tension or mechanical stretch from part of the coronary artery causes the longitudinal fissure at the weakened site of the plaque cap.

[A case of nonarteritic anterior ischemic optic neuropathy with cilioretinal artery occlusion]

We report a case of nonarteritic anterior ischemic optic neuropathy (AION) with cilioretinal artery occlusion. The patient was a 61-year-old man with sudden visual loss in his right eye. Funduscopy showed pale swelling of the entire optic disc with retinal ischemic edema of the upper half of the retina, and fluorescein angiography revealed faint filling of the dye in the optic disc in the retinal arterial phase, and dye staining of the optic disc in the late phase. We initially diagnosed the disease as AION with branch retinal artery occlusion, but systemic administration of a corticosteroid and urokinase were ineffective and the optic disc became atrophic. As the optic disc swelling decreased and the course of arteries in the optic disc became clear, we repeated fluorescein angiography which proved that the involved upper retinal artery was a cilioretinal artery having earlier dye appearance than the lower retinal artery. Thus, we finally diagnosed the disease as AION with cilioretinal artery occlusion. We believe that Hayreh's view that AION may result from occlusion of the posterior ciliary artery is supported by the intraocular findings in this case.

Postmenopausal bone loss in Japanese women

OBJECTIVES

Our purpose was to detect anatomic variations in postmenopausal bone loss and to determine the risk factors most affecting bone mass in Japanese women.

METHODS

One hundred sixty-six Japanese women (54 premenopausal and 112 postmenopausal), aged 40-68 years, were enrolled in the study. Bone mineral densities (BMD) of the lumbar spine (L2-4) and total body were measured by dual energy X-ray absorptiometry and the results were subjected to statistical analysis.

RESULTS

Among the various sites studied, the lumbar spine (L2-4) showed the fastest bone loss after menopause. Multiple regression analysis indicated that two factors, number of years since the menopause and body mass index (BMI), affected lumbar spine (L2-4) BMD.

CONCLUSION

Measurement of lumbar spine (L2-4) BMD is suitable for evaluating postmenopausal osteoporosis. The risk factors for postmenopausal bone loss were a long period after menopause and a low BMI.

Effect of body position on the blood gases and ventilation volume of infants with chronic lung disease before and after feeding

The effect of body position before and after tube feeding was evaluated in six extremely immature infants who were being mechanically ventilated because of chronic lung disease. Their mean birthweight and gestational age were 722.7 g (range, 540 to 994) and 24.9 weeks (range, 23.9 to 26.0), respectively. This study was performed at a mean postnatal age of 47.5 days (range, 21 to 85 days). The prone position resulted in a significant increase in arterial oxygen saturation before and after feeding, whereas the tidal volume demonstrated an increase only before feeding. Also the prone position showed a significant decrease in heart rate before and after feeding and a tendency to decrease transcutaneous carbon dioxide tension values before feeding. There were no significant differences in minute ventilation despite increased tidal volume in the prone position, most likely due to a decrement of the spontaneous respiratory rate in the prone positioning. We conclude that the prone position may offer an advantage over the supine position in the management of extremely immature infants with chronic lung disease before and after feeding.

Adjustments of cardiac function during prolonged exercise relative to lactate threshold

Alterations in cardiac function during prolonged submaximal exercise relative to lactate threshold (LT) were evaluated on 7 normal healthy males aged 30.3 +/- 5.7 years. Systolic time intervals were analyzed through simultaneous recordings of electrocardiogram, phonocardiogram, and impedance cardiogram at a paper speed of 50 mm/s. Determination of stroke volume (SV) was based upon the method described by Kubicek et al. ANOVA followed by the Scheffe post-hoc comparison revealed that SV and myocardial contractility indices (MSER and PEP/LVET) remained relatively unchanged throughout 40-min cycling exercise, although the changes in heart rate and oxygen uptake were statistically significant. In addition, systolic blood pressure remained almost unchanged during the exercise. These results may be interpreted as evidence of the "contractility reserve", i.e., the ability of maintaining heart muscle contractility during prolonged exercise at LT intensity.

Congenital pseudarthrosis of the clavicle. Histologic examination for the etiology of the disease

The etiology of congenital pseudarthrosis of the clavicle remains obscure. The authors treated a 5-year-old boy with this rare disease. Clinical history and radiographs confirmed the diagnosis. Surgical treatment of resection of the pseudarthrosis, autologous bone graft, and internal fixation with a small AO plate led to successful bone union. Histologic analysis of the pseudarthrosis showed that there were cartilaginous caps on the proximal and distal bony ends. The appearance of the cartilaginous caps were equivalent to that of developing physes. They were adding new bone to the bony ends, which also was confirmed by preoperative tetracycline labeling. These observations support the hypothesis that the pseudarthrosis is caused by failure of 2 ossification centers to fuse, as was previously proposed by others.

Molecular cloning and in situ localization in the brain of rat sky receptor tyrosine kinase

We previously identified a human cDNA encoding a novel receptor tyrosine kinase, termed Sky, which is predominantly expressed in the brain and has a unique extracellular domain consisting of two immunoglobulin (Ig)-like and two fibronectin type III (FN III) motifs. In attempts to define the functional role of the Sky receptor, we cloned a rat sky cDNA, and localized the sites of expression of sky transcript in the adult rat brain by Northern blot and in situ hybridization analyses using the cloned rat cDNA as a probe. The deduced amino acid sequence of rat Sky has an overall sequence and a domain topology highly conserved with human Sky (90% overall identity and 98% identity within the tyrosine kinase domain). Northern blot analysis revealed that a single 3.8-kb sky mRNA is expressed in PC12 pheochromocytoma and Neuro-2a neuroblastoma cell lines and in various regions of the adult rat brain. In situ hybridization analysis revealed widespread but confined neuronal populations in adult rat brain that express sky transcript; prominent hybridization signals were detected in the inner granular layer of the olfactory bulb, CA-1 area of the hippocampus, granule cell layer of the cerebellum, tenia tectum and cingulate gyrus neurons, and wide regions of cortex layers II-VI. The high level of expression of sky mRNA in neurons in restricted brain regions suggests that the Sky receptor may play an important role in development, function, and maintenance of specific neuronal populations in the central nervous system.

Conventional protein kinase C (PKC)-alpha and novel PKC epsilon, but not -delta, increase the secretion of an N-terminal fragment of Alzheimer's disease amyloid precursor protein from PKC cDNA transfected 3Y1 fibroblasts

A large soluble N-terminal fragment of Alzheimer's disease amyloid precursor protein (secreted form of APP: APPs) is produced by constitutive processing in the middle of the amyloid beta-protein portion of APP. Recent studies indicate that the activation of endogenous protein kinase C (PKC) with phorbol ester raises the rate of secretion of APPs. We constructed rat fibroblast 3Y1 cells that stably overexpress PKC isoenzymes alpha, delta, or epsilon, and analyzed the amount of APPs released from these PKC transfectants. The levels of APPs released from 3Y1 cells overexpressing PKC alpha and -epsilon were higher than those from PKC delta-transfected and control cells expressing vector only. These results suggest that specific isoforms of PKC regulate the secretion of APPs through a signaling pathway.

Angioscopic identification of coronary thrombus in patients with postinfarction angina

OBJECTIVES

The purpose of this study was to determine the prevalence of intracoronary thrombus and associated anatomic abnormalities in patients with postinfarction angina using coronary angioscopy and angiography.

BACKGROUND

Postinfarction angina, previously studied by angiographic methods only, identifies patients at high risk for sudden death, recurrent angina and refractory angina. The recent development of coronary angioscopy, which permits direct observation of a thrombus or atheroma and is especially used for the detection of intraluminal changes, encourages a reexamination of the pathogenesis of postinfarction angina.

METHODS

Fifty-one consecutive patients with a diagnosis of acute myocardial infarction underwent cardiac catheterization. Coronary angiography followed immediately by coronary angioscopy was performed in 17 patients with and 34 without postinfarction angina during the same period of time (10.2 +/- 3.7 or 15.7 +/- 5.5 days [mean +/- SD]) after the onset of acute myocardial infarction.

RESULTS

The frequency of thrombus, as observed by angioscopy, was significantly higher in patients with than without postinfarction angina (17 of 17 vs. 5 of 34, respectively, p < 0.01). There were no significant differences between groups with respect to degree of stenosis in the infarct-related artery, number of vessels with significant stenosis, presence of collateral flow, type of therapy and risk factors.

CONCLUSIONS

Infarct-related artery thrombus is universally present in postinfarction angina and may be the primary pathogenic factor. Angioscopy is much more sensitive than coronary angiography for the detection of coronary thrombus.

Clinical evaluation of titration of hepatitis C virus core antibody and its subclasses

Titrations of anti-hepatitis C core (anti-HCc) immunoglobulin G (IgG) antibodies and its subclasses were studied in 90 patients with acute and chronic hepatitis C virus (HCV) infection, including 27 patients who underwent interferon (IFN) therapy. The positivity rates for each anti-HCc subclass were as follows: 95.2% for IgG1, 12.0% for IgG2, 69.9% for IgG3 and 19.3% for IgG4. The total anti-HCc IgG titre correlated well with the IgG1, titre, indicating that IgG1 was the main virus-specific IgG. Changes of IgG1 production mainly contributed to fluctuations of the anti-HCc IgG titre and corresponded well to positivity for HCV-RNA during and after IFN therapy. IgG3 was detected prior to IgG1 during the early phase of acute hepatitis in some cases and also appeared with relapse after IFN therapy. The serial assay of anti-HCc subclasses showed the patients' humoral immune response to HCV infection, and might be useful for evaluation of anti-viral immunity influenced by IFN therapy.

Autophosphorylation activity and association with Src family kinase of Sky receptor tyrosine kinase

"Sky" is a putative receptor tyrosine kinase predominantly expressed in the brain. Sky, like Axl/Ufo/Ark and c-Eyk, has an extracellular domain composed of two immunoglobulin-like domains and two fibronectin type III domains. Immunoblot analysis using an antibody raised against a C-terminal peptide of Sky identified a 98-kDa Sky protein in COS cells transfected with sky cDNA (COS/sky cells). A 98-kDa protein in the immunoprecipitates with anti-Sky antibody was autophosphorylated on tyrosine, by in vitro kinase reaction. When the lysates of COS/sky cells were immunoprecipitated with anti-Sky antibody and immunoblotted with an anti-phosphotyrosine antibody, a 60-kDa phosphotyrosine-containing protein, in addition to the tyrosine-phosphorylated Sky, was detected. Using the anti-Src antibody, which is reactive to Src, Fyn and Yes, we obtained evidence for an association between the Src family tyrosine kinase and the tyrosine-phosphorylated Sky receptor. These results suggest that the Src family kinase may play an important role in signal transduction of the Sky receptor.

In vivo angioscopic detection of the damaged endothelium on the atheromatous plaque: application with vital staining by methylene blue

We attempted to detect the lesion of the damaged endothelium on the atherosclerotic plaque in vivo with dye and angioscope. The plaques were induced on the aortae of rabbits by the continuous mechanical injury with the insertion of the polyethylene tube and feeding with 2% cholesterol-added diet. We observed the some plaques could be stained with 5 x 10(-2) mol/L methylene blue by angioscope. Control aorta, without any stimulations on the aorta, could not be stained. One month after injury and cholesterol feeding the plaques were stained. In such plaques, the lack of the endothelium and the existence of the lipid-containing cell in the intima was observed. However, the plaques of the aorta 6 months after finishing these procedures could not be stained. In these plaques, the morphological characteristics known as the regression of the atheromatous plaque, ie, the regeneration of the endothelium, the thick collagen layer on the plaque and the massive calcification of the plaque were observed. The results obtained were as follows. (1) The atheromatous lesion with the damaged endothelium could be detected in vivo by our vital staining method. (2) The atheromatous plaques stained in vivo are the lesion with complication and enhanced permeability. (3) The slightly stained plaques indicate the lesions with regression and lost high permeability. (4) Our method would be able to add important information on the atheroscrelotic lesions in the clinical situations than that now we perform.

Effects of glycolytic metabolites on preservation of high energy phosphate level and synaptic transmission in the granule cells of guinea pig hippocampal slices

The present study was undertaken to investigate whether neural activity of hippocampal slices can be preserved after replacing D-glucose with glycolytic intermediate metabolites such as lactate, pyruvate and citrate or with other sugars such as fructose, mannose, maltose, glucosamine, sucrose and galactose. As an index of neural activity, population spikes (PS) were recorded in the granule cell layers after electrical stimulation to the perforant path of guinea pig hippocampal slices. In addition, we determined the levels of ATP and creatine phosphate (CrP) in each slice after the replacement of D-glucose with these substrates, and correlated it with the neural activity. Substrates other than D-glucose could not maintain the PS for even 20 min although the slices perfused with medium containing lactate, pyruvate, galactose, fructose and maltose maintained similar levels of ATP and CrP as in slices incubated in the D-glucose-containing medium. These results indicate that D-glucose is essential for the preservation of synaptic activity in addition to its main role as the substrate for energy production to maintain the levels of high energy phosphates.

Surfactant protein-B supplementation improves in vivo function of a modified natural surfactant

The effect of the addition of surfactant protein (SP)-B or SP-B plus SP-C (SP-BC) to a surfactant made from bovine lung (Survanta) was evaluated in 27-d-gestation preterm rabbits. The animals were treated with Survanta, Survanta + 2% SP-B, Survanta + 3% SP-BC, or sheep surfactant. They were then ventilated with 3 cm H2O positive end-expiratory pressure and tidal volumes of 8 mL/kg. Survanta + 2% SP-B was prepared by adding SP-B in water to Survanta or by adding SP-B in chloroform [SP-B(Chl)] to lipid-extracted Survanta. Dynamic compliances of the Survanta + 2% SP-B(Chl)- and Survanta + 3% SP-BC-treated rabbits were greater (p < 0.05) than those treated with Survanta or Survanta + 2% SP-B in water and were comparable to sheep surfactant. Postventilation pressure-volume curves for the groups treated with Survanta supplemented with SP-B had significantly larger retained volumes on deflation compared with those treated only with Survanta (p < 0.01). The effects of ventilation style on the responses were assessed by ventilating other groups of rabbits treated with Survanta, Survanta + 0.5% SP-B(Chl), Survanta + 2% SP-B(Chl), or sheep surfactant with tidal volumes of 10 mL/kg and 0 cm H2O positive end-expiratory pressure. SP-B (2%) augmented the in vivo function of Survanta without positive end-expiratory pressure, and 0.5% SP-B had no effect. Infasurf, a surfactant with more SP-B, was more effective than Survanta when tested in the preterm rabbits. SP-B is a critical factor for optimum immediate surfactant function.

UCN-01, an anti-tumor drug, is a selective inhibitor of the conventional PKC subfamily

A selective PKC inhibitor, UCN-01, was shown to exhibit anti-tumor activity in vitro and in vivo. We investigated UCN-01 with respect to isozyme-specific PKC inhibition using purified recombinant or rabbit brain PKC isozymes, cPKC alpha, beta and gamma, nPKC delta, epsilon and eta, and a PKC zeta. Of the PKC isozymes examined, cPKC alpha was inhibited by UCN-01 most effectively (Ki = 0.44 nM), suggesting cPKC alpha is the prime candidate for the physiological target of UCN-01. The Ki values of UCN-01 estimated from Dixon plots for cPKC isozymes are approximately 1 nM, whereas the Ki values for nPKC isozymes are about 20 nM. Moreover, the Ki value for aPKC zeta is 3.8 microM. Thus, UCN-01 discriminates between PKC subfamilies. In addition, the inhibitory effects of staurosporine, H7, and calphostin C on aPKC zeta were examined and compared with those for cPKC alpha.

A protein kinase C isozyme, nPKC epsilon, is involved in the activation of NF-kappa B by 12-O-tetradecanoylphorbol-13-acetate (TPA) in rat 3Y1 fibroblasts

In order to examine whether PKC is involved in the activation of NF-kappa B by TPA, we overexpressed a variety of PKC isozymes in rat 3Y1 fibroblasts and monitored the expression of the co-transfected reporter NF-kappa B gene. In contrast to TPA response element (TRE), where overexpression of a variety of PKC isozymes results in enhanced activation by TPA, activation of NF-kappa B by TPA is not enhanced by overexpression of PKC isozymes such as cPKC alpha, nPKC delta, or nPKC theta. However, the overexpression of nPKC epsilon does result in enhancement. A kinase-negative point mutant of nPKC epsilon, where Lys at the ATP binding site is altered to Arg, does not cause this enhancement of NF-kappa B activation. Further, the kinase-negative nPKC epsilon partially suppresses endogenous NF-kappa B activity. These results suggest that nPKC epsilon is specifically involved in the activation of NF-kappa B when cells are treated with TPA.

Contrasting effect of interleukin-13 on interleukin-1 receptor antagonist and proinflammatory cytokine production by human alveolar macrophages

We investigated the effect of interleukin-13 (IL-13) on production of IL-1 receptor antagonist (IL-1ra) and proinflammatory cytokines by human alveolar macrophages (AM). AM were obtained by bronchoalveolar lavage from healthy donors. The production of IL-1ra and proinflammatory cytokines, such as IL-1 beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha), were quantitated by enzyme immunoassays. AM spontaneously produced IL-1ra, and this production was significantly augmented by IL-13. On the other hand, IL-13 alone did not affect production of proinflammatory cytokines by freshly isolated AM. Upon stimulation with lipopolysaccharide (LPS), AM produced a significantly amount of proinflammatory cytokines as well as IL-1ra, but this production was suppressed by IL-13 in a dose-dependent manner. In contrast, IL-13 caused a small but reproducible increase in LPS-induced IL-1ra production. These regulatory effects of IL-13 were also observed in blood monocytes and macrophages generated in vitro by maturation of blood monocytes with granulocyte/macrophage colony-stimulating factor. These observations suggest that IL-13 may act as an anti-inflammatory cytokine through regulation of cytokine production by AM in the lung.

Clinical value of a new serum tumor marker, CA125II, in gynecologic disease: comparison with CA125

CA125 II, an improved version of the conventional CA125 was compared with CA125 as to which was more useful in gynecologic disease. In the diagnosis of tumors around the adnexal field (primary epithelial ovarian cancer, metastatic ovarian cancer, benign ovarian tumor and endometrial cyst), CA125 II showed the same sensitivity and specificity as CA125. CA125 II also has high simultaneous reproducibility in the low concentration area. The examination by the receiver operating characteristic curve revealed that CA125 II has higher precision than that of CA125 when it is used for the screening test. In conclusion, CA125 II is a better tumor marker than conventional CA125.

Interaction between pregnancy-induced bioactive peptides and the placental proteases

Studies have shown that placental proteases metabolize vasoactive peptides, possibly derived from the fetus, and protect the exchange of peptide hormones across the placenta in order to maintain feto-placental homeostasis. Changes in maternal serum protease activities were useful for monitoring pre-eclampsia and predicting the onset of labour. The study showed that possible role of oxytocinase in the maintenance of gestation and the possible involvement of angiotensinase in the attenuated pressor responses to angiotensin II during pregnancy, respectively. In addition, the ratio of peak systolic over least diastolic pressure (S/D) of uterine or umbilical artery assessed by the Doppler technique was closely correlated with the concentrations of maternal serum proteases in pre-eclampsia, which suggested that placental proteases might control utero-placental circulation via the regulation of concentrations of vasoactive peptides in uteroplacental circulation.