Spatiotemporal changes of coxsackievirus and adenovirus receptor in rat hearts during postnatal development and in cultured cardiomyocytes of neonatal rat

Coxsackievirus B is the most common cause of viral myocarditis and is particularly virulent in neonates and children. Adenovirus is also a leading cause of the disease. The determinant of tropism for both viruses is considered to be the expression of coxsackievirus and adenovirus receptor (CAR) in target organs. However, developmental change and physiological localization of CAR in the heart are unknown. We examined expression levels of CAR in rat hearts by quantitative real-time polymerase chain reaction and Western blot analysis and found that CAR decreased gradually during postnatal development, although CAR was detectable, even in adults. Immunohistochemistry revealed CAR on the whole surface of cardiomyocytes in immature rat hearts. In contrast, CAR was detected predominantly on intercalated disks in the adult heart and was accumulated especially at the contact point between the cultured cardiomyocytes, even though they were prepared from the neonatal rat heart. In conclusion, CAR was expressed abundantly on the whole surface of cardiomyocytes in immature rat hearts. Both the expression level and the localization of CAR are possible determinants of the susceptibility to viral myocarditis of neonates and children.     

Airway responsiveness and airway remodeling after chronic exposure to procaterol and fenoterol in guinea pigs in vivo

BACKGROUND: Chronic exposure to fenoterol (FEN), a beta(2)-adrenergic receptor (beta(2)-AR) agonist, was shown to induce both airway hyperresponsiveness and airway remodeling in experimental animals. OBJECTIVE: We wanted to know the effects of chronic exposure to procaterol (PRO), a beta(2)-AR agonist, on airway function and structure, because this agent is widely used as a bronchodilator in Japan. For comparison, the effects of FEN were also examined. METHODS: Aerosolized PRO (0.1 or 1 mg/ml), FEN (1 mg/ml) or vehicle (0.9% NaCl) was given to guinea pigs 3 times a day for 6 weeks. Sublaryngeal deposition of these agents was calculated using radioisotopes. At 72 h after the last inhalation of PRO, FEN or vehicle, the dose-response relationship between lung resistance (R(L)) and intravenously administered acetylcholine (ACh) was measured. After measuring R(L), histological changes in noncartilaginous airway dimensions were evaluated. RESULTS: The amount of sublaryngeal deposition of 0.1 mg/ml PRO in the present study was speculated to be 100 times larger than that of therapeutic dose. ACh concentrations causing 2-fold, 10-fold and maximal increases in R(L) were not different in 4 groups tested. In the smaller membranous airways (<0.4 mm in diameter), but not the larger ones, thickening of adventitial areas was significantly greater in animals treated with beta(2)-AR agonists than in control animals (23 and 25, and 96% higher in animals treated with 0.1 and 1 mg/ml PRO or 1 mg/ml FEN, respectively). The degree of the increase was significantly less in PRO-treated animals than in FEN-treated animals (p < 0.01). CONCLUSION: Our results did not provide any evidence that regular inhalation of PRO at the therapeutic dose might induce bronchial hyperresponsiveness. In addition, huge amounts of PRO only caused a mild thickening of the adventitial areas, suggesting that PRO may be a weak inducer of airway remodeling compared with FEN.     

Protective effect of recombinant neutrophil elastase inhibitor (R-020) on sepsis-induced organ injury in rat

Severe inflammatory responses after major surgeries, trauma, and infection develop multiple organ dysfunction. In the mechanisms of the pathogenesis of these responses, activated neutrophils are thought to be important in terms of their ability to produce various kinds of proteinases, which can degrade various proteins constructing human tissues. Among their proteinases, neutrophil elastase is the strongest serine proteinase secreted from activated neutrophils. Thus, we examined in this study the inhibitory effect and therapeutic efficacy of newly produced recombinant human Kunitz-type proteinase inhibitor (R-020), which coded the second domain of human urinary trypsin inhibitor. R-020 was effective in significantly improving the survival rate after induction of the rat lethal peritonitis model (cecal ligation and punctureinduced septic shock model). We suggest that various serine proteinases are implicated in the pathogenesis of neutrophil-related multiple organ failure and that recombinant human Kunitz-type proteinase inhibitor might be effective in the treatment of these kinds of organ dysfunction.     

Clinical significance of measurement of resting energy expenditure in childhood

1. Biliary atresia (BA), as a common disease in Japan, and cystic fibrosis (CF), as an extremely uncommon disease in Japan, were selected to assess the clinical significance of measurement of energy expenditure (EE). 2. Energy expenditure was significantly higher in children with BA than in normal children. 3. Measurement of EE in BA lead to clues to resolving its mechanism by novel assessment of interleukin-6 and leptin. 4. Energy expenditure in children with CF is also higher, but this has been addressed by nutritional intervention with additional calories. 5. Individualization of EE measurement is necessary in the analysis of pathological mechanisms and nutritional management of patients with both common and uncommon diseases.     

Estimation of quantal parameters at the calyx of Held synapse

The calyx of Held has recently emerged as a convenient model system to study CNS synapses. In order to understand the mechanisms of synaptic transmission and short-term synaptic plasticity, quantal parameters and their changes should be estimated precisely. For this purpose, various methods have been applied to the calyx of Held synapse. The results confirm many aspects of the early findings on transmission at the neuromuscular junction. On the other hand, the simplest quantal hypothesis does not work at the calyx of Held, because of additional factors such as heterogeneous release probability of synaptic vesicles, intra- and intersite quantal variability, an overlap of facilitation and depression of transmitter release, changes in quantal sizes due to desensitization and saturation of postsynaptic receptors, and delayed clearance of transmitter from the synaptic cleft. These factors should always be taken into account for fully understanding the mechanisms of synaptic transmission and plasticity.     

Influence of internal and external donors on activity and stereospecificity of ziegler-natta catalysts

Three kinds of MgCl₂-supported TiCl₄ catalysts (ester-free, ethyl benzoate (EB, monoester) and dibutyl phthalate (DNBP, diester) as internal donors) were prepared. Polymerization of propylene was carried out using these catalysts with and without phenyltriethoxysilane (PTES) as an external donor. Significant differences were observed in the kinetic behavior of polymerization among ester-free, monoester, and diester systems. Addition of PTES, however, did not change the kinetic behavior. The polymers produced were separated into three fractions by extraction with boiling heptane and octane, and the molar mass distribution (MMD) curves were measured for these three fractions. The heptane-insoluble, isotactic polymer obtained in the absence of PTES was found to consist of two fractions, octane-soluble and -insoluble. The octane-soluble polymer having lower molar mass contained appreciable amounts of syndiotactic stereoblocks in the chains, whereas the octane-insoluble polymer did not contain such stereoblocks. Addition of PTES drastically increased the octane-insoluble fraction without changing the average molar mass. On the other hand, the MMD curve for the heptane-soluble, atactic polymer gradually shifted to the lower molar mass range with an increase in the concentration of PTES. From these results, the effects of internal and external donors on catalyst activity and stereospecificity were discussed putting emphasis on the differences between monoesters and diesters.     

Validity of heart rate and ratings of perceived exertion as indices of exercise intensity in a group of children while swimming

Summary The purpose of this study was to investigate the validity of heart rate (f _c) and ratings of perceived exertion (RPE) as indices of exercise intensity in a group of children while swimming. Six healthy male swimmers, aged 10–12, swam tethered using the breast-stroke in a flume. The resistance started at 1.0 kg and increased in 1.0 kg steps up to the point of their exhaustion. The subjects swam for 5 min during each period, with a rest of 10–20 min until they had returned to their resting f _c level. The last exercise intensity was with the maximal mass the subjects could support for 2 min. The last min of oxygen consumption (VO₂) and 30 s of f _c were measured during each exercise period. The subjects gave their RPE assessment at the end of exercise.The individual relationships between f _c and VO₂, and percentage maximal oxygen consumption (% VO_2max, were linear with a high correlation r=0.962–0.996 and r=0.962–0.996, respectively. Therefore, it was concluded that f _c was valid as an index of the exercise intensity of children while swimming. Compared to the results found in adults using a similar protocol, the children's f _c were 8.3–26.9 beats·min^–1 higher than those of the adults at the given % VO_2max. The present study showed two different patterns in the relationship between VO₂ and RPE in individuals. In two subjects the RPE increased linearly with VO₂ while in the other four subjects the increase was discontinuous. If f _c and RPE were to be applied to the setting and evaluation of exercise intensity during swimming, it would seem that f _c would be a more useful guide than RPE for some children.     

A "floral" variant of nodal marginal zone lymphoma

We describe 6 cases of a specific variant of nodal marginal zone lymphoma with "floral" lymph follicles in patients ranging in age from 18 to 66 years. All 6 patients had lymphadenopathy, either local (n = 5) or systemic (n = 1), and good performance status (0), and none had fever, weight loss, or night sweating. They all underwent excisional biopsy. Histologically, all lesions had a distinctive morphology, with proliferation of medium-sized atypical lymphoid cells in the marginal zone, hyperplastic lymph follicles with enlarged germinal centers, and a thickened mantle zone. In places, folliculolysis was observed. On immunohistochemical staining, the atypical lymphoid cells showed a B-cell phenotype (CD20 +), IgM positivity in 2 of 5 cases, and negativity for CD5, CD10, CD23, CD43, bcl-6, and IgD. Polymerase chain reaction examination for immunoglobulin heavy chain in 5 cases showed monoclonality in all. Five patients did not receive adjuvant chemotherapy and had no recurrences. The patient with systemic lymphadenopathy received chemotherapy and had a complete response without relapse. This variant should be differentiated from the usual nodal marginal zone lymphoma because of its specific clinical and pathological features.     

Immunohistochemical analysis of MCT1, MCT2 and MCT4 expression in rat plantaris muscle

All three forms of recombinant low voltage-activated T-type Ca²⁺ channels (Ca_v3.1, Ca_v3.2 and Ca_v3.3) exhibit a small, though clearly evident, window T-type Ca²⁺ current ( I _Twindow) which is also present in native channels from different neuronal types. In thalamocortical (TC) and nucleus reticularis thalami (NRT) neurones, and possibly in neocortical cells, an I _Twindow-mediated bistability is the key cellular mechanism underlying the expression of the slow (< 1 Hz) sleep oscillation, one of the fundamental EEG rhythms of non-REM sleep. As the I _Twindow-mediated bistability may also represent one of the cellular mechanisms underlying the expression of high frequency burst firing in awake conditions, I _Twindow is of critical importance in neuronal population dynamics associated with different behavioural states.     

Lipoteichoic acids from Lactobacillus strains elicit strong tumor necrosis factor alpha-inducing activities in macrophages through Toll-like receptor 2

Lactobacilli are nonpathogenic gram-positive inhabitants of microflora. At least some Lactobacillus strains have been postulated to have health beneficial effects, such as the stimulation of the immune system. Here we examined the stimulatory effects of lactobacilli on mouse immune cells. All six heat-killed Lactobacillus strains examined induced the secretion of tumor necrosis factor alpha (TNF-alpha) from mouse splenic mononuclear cells, albeit to various degrees. When fractionated subcellular fractions of Lactobacillus casei were tested for NF-kappaB activation and TNF-alpha production in RAW264.7, a mouse macrophage cell line, the activity was found to be as follows: protoplast > cell wall > polysaccharide-peptidoglycan complex. Both crude extracts and purified lipoteichoic acids (LTAs) from two Lactobacillus strains, L. casei and L. fermentum, significantly induced TNF-alpha secretion from RAW264.7 cells and splenocytes of C57BL/6, C3H/HeN, and C3H/HeJ mice but not from splenocytes of C57BL/6 TLR2(-/-) mice. Lactobacillus LTA induced activation of c-Jun N-terminal kinase activation in RAW264.7 cells. Furthermore, in HEK293T cells transected with a combination of CD14 and Toll-like receptor 2 (TLR2), NF-kappaB was activated in response to Lactobacillus LTA. Taken together, these data suggest that LTAs from lactobacilli elicit proinflammatory activities through TLR2.