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.     

Three-dimensional two-layer collagen matrix gel culture model for evaluating complex biological functions of monocyte-derived dendritic cells

Dendritic cell-like cells (Mo-DCs) generated from peripheral blood monocytes with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have been used as tools to treat cancer patients (DC-vaccines). Because Mo-DCs have multiple antigen presentation-related functions, including phagocytosis, migration, cytokine production, and T cell stimulation, establishment of a method for simultaneously evaluating the various functions of Mo-DCs is important. We developed a new in vitro three-dimensional two-layer collagen matrix culture model that consists of a collagen gel containing Mo-DCs as the lower layer and a collagen gel containing necrotic GCTM-1 tumor cells and/or T cells as the upper layer. We used this system to observe simultaneously multiple functions of Mo-DCs by phase-contrast or fluorescence microscopy and to assess IL-12 secretion during more than 2 weeks of culture. We also observed interactions between Mo-DCs and necrotic GCTM-1 or T cells on an individual cell basis by time-lapse videomicroscopy. In addition, we collected Mo-DCs from the collagen gels by collagenase treatment and analyzed the expression of antigen presentation-related molecules such as HLA-DR, CD80, CD83, and CD86 on Mo-DCs. This model may be a useful tool for evaluation of the various functions of Mo-DCs used as DC vaccines and for studies of the complex behaviors of Mo-DCs in vivo.     

Ultrastructure and synaptic organization of the spinal accessory nucleus of the rat

The accessory nucleus is composed of neurons in the medial column that innervate the sternocleidomastoid muscle, and neurons in the lateral column that innervate the trapezius muscle. We retrogradely labeled these neurons by injection of cholera toxin conjugated horseradish peroxidase into the sternomastoid (SM) or the clavotrapezius (CT) muscles, and investigated fine structure and synaptology of these neurons. Almost all SM and CT motoneurons had the appearance of alpha-motoneurons, i.e., large, oval or polygonal cells containing well-developed organelles, Nissl bodies, and a prominent spherical nucleus. More than 60% of the somatic membrane was covered with terminals. The SM motoneurons (34.4 x 52.2 microm, 1,363.1 microm(2) in a section) were slightly larger than the CT motoneurons (32.8 x 54.2 microm, 1,180.8 microm(2)). The average number of axosomatic terminals in a section was 52.2 for the SM, and 54.2 for the CT motoneurons. More than half of them (58.0%) contained pleomorphic vesicles and made symmetric synaptic contacts (Gray's type II) with the SM motoneurons, while 57.9% of them contained round vesicles and made asymmetric synaptic contacts (Gray's type I) with the CT motoneurons. A few C-terminals were present on the SM (3.5) and the CT (3.7) motoneurons. About 60% of the axodendritic terminals were Gray's type I in both the SM and the CT motoneurons. A few labeled small motoneurons were also found among the SM and the CT motoneurons. They were small (19.2 x 26.2 microm, 367.0 microm(2)), round cells containing poorly developed organelles with a few axosomatic terminals (9.3). Only 20% of the somatic membrane was covered with the terminals. Thus, these neurons were presumed to be gamma-motoneurons. These results indicate that the motoneurons in the medial and the lateral column of the accessory nucleus have different ultrastructural characteristics.     

Effects of nocturnal bright light on saliva melatonin, core body temperature and sleep propensity rhythms in human subjects

Nine healthy male volunteers (mean age of 24) participated in two experimental sessions of random crossover design: a bright light (5000 lux for 5 h from 00:00 to 05:00 h) session and a dim light (10 lux for 5 h from 00:00 to 05:00 h) session. Subsequently participants entered an ultra-short sleep-wake schedule for 26 h, in which a sleep-wake cycle consisting of 10-min sleep EEG recording on a bed and 20-min resting awake on a semi-upright chair were repeated. Saliva melatonin level and core body temperature was measured throughout the experiment. Bright light significantly delayed rhythms of melatonin secretion (01:58 h), core body temperature (01:12 h) and sleep propensity (02:00 h), compared as dim light session. Significant positive correlation was found between bright light-induced phase change in core body temperature and that in sleep propensity rhythm. Light-induced melatonin suppression significantly positively correlated with the phase change in core body temperature and that in sleep propensity rhythm. Assuming that light-induced melatonin suppression represents an acute impact of light on the circadian pacemaker, our results suggest that such an impact may be directly reflected in phase changes of sleep propensity and core body temperature rhythms rather than in melatonin rhythm.     

Immunohistochemical detection of hepatocellular carcinoma in the setting of ongoing necrosis after radiofrequency ablation.

After radiofrequency ablation (RFA), hepatocellular carcinoma undergoes complete necrosis and an ongoing necrosis that is irreversible and characterized histologically by disrupted cell outlines, homogenous cytoplasmic eosinophilia, and preserved nuclear staining, with the cells appearing quite distinct from viable cancer cells. Antibody to detect single-stranded DNA (ssDNA) specifically labeled nuclei in the setting of ongoing necrosis, but not viable tumor cells, whereas human mitochondrial antibody labeled the cytoplasm of viable cells but not cells of ongoing necrosis. The results demonstrate that RFA causes denaturation of both DNA and proteins and that the immunohistochemistry of ssDNA and mitochondrial protein is useful in detection of ongoing necrosis after RFA and provides pathological information on the validity of this procedure.     

Polymorphisms and the differential antiviral activity of the chicken Mx gene

The nucleotide sequence of chicken Mx cDNA was reported earlier using the White Leghorn breed in Germany, but it showed no enhanced resistance to viruses. In this study, the nucleotide sequences of chicken Mx cDNA were determined in many breeds. A total of 25 nucleotide substitutions, of which 14 were deduced to cause amino acid exchanges, were detected, suggesting that the chicken Mx gene is very polymorphic. Transfected cell clones expressing chicken Mx mRNA were established after the Mx cDNA was constructed with an expression vector and introduced into mouse 3T3 cells, and the Mx genes from some breeds were demonstrated to confer positive antiviral responses to influenza virus and vesicular stomatitis virus. On the basis of the comparison among the antiviral activities associated with many Mx variations, a specific amino acid substitution at position 631 (Ser to Asn) was considered to determine the antivirally positive or negative Mx gene. Thus, a single amino acid substitution influences the antiviral activity of Mx in domesticated chickens.     

Role of KCNQ1 in the cell swelling-induced enhancement of the slowly activating delayed rectifier K(+) current

Cell swelling enhances a slowly activating delayed rectifier K(+) current (I(Ks)) in cardiac cells. This investigation was undertaken to determine which of the two structural units reconstituting the I(Ks) channel, KCNQ1 (KvLQT1) and KCNE1 (minK/IsK), plays a key role in the cell swelling-induced I(Ks) enhancement and to dissect a possible involvement of tyrosine phosphorylation therein. KCNQ1 was transiently expressed alone or together with KCNE1 in a heterologous mammalian cell line. Two distinct whole-cell membrane currents were separately observed during the exposure of transfected cells to various degrees of hyposmotic solutions. A hyposmotic challenge (0.7 times control osmolarity) resulted in about a twofold increase not only in the heteromeric KCNQ1/KCNE1, but also in the homomeric KCNQ1 channel currents. There was no significant difference in the incremental ratio of current amplitude in response to hyposmotic stress between the two KCNQ1-related currents, and the cells expressing the heteromeric channels swelled less than those with the homomeric channels or without the exogenous ones. The cell swelling-induced I(Ks) enhancement was not affected by a protein tyrosine kinase (PTK) inhibitor, by genistein (50 microM), or by an inhibitor of phosphotyrosine phosphatase (PTP), orthovanadate (500 microM), or a nonhydrolyzable ATP analogue, AMP-PNP (5 mM). Taken together, it is very likely that KCNQ1 might primarily participate in the I(Ks) enhancement by osmotic cell swelling. The obligatory dependence of the I(Ks) augmentation on PTK activity remained to be demonstrated, at least, in this expression system.     

Organ design for generation and reception of CO: lessons from the liver

Carbon monoxide (CO) is synthesized in vivo by heme oxygenase. Although for many years CO had been regarded as potentially toxic waste, recent studies have indicated that it is a signaling molecule with important physiological functions. Nitric oxide (NO), another diatomic diffusible gas, is regarded as an established signaling molecule. Structural similarities between CO and NO have led many investigators to draw analogies between the two gaseous mediators. Whereas the NO signaling system has been well defined as to its receptor molecule, soluble guanylate cyclase, the CO system has been conceived to require further tuning with respect to identifying its receptor molecules and its downstream effectors. Furthermore, there has been little quantitative information to argue for a physiological role of CO in vivo. This review, therefore, focuses on recent developments on both physiologic and pathophysiologic roles of CO in the model of isolated perfused liver of rats where endogenous production of CO is actually estimated. This model has revealed that CO acts as an endogenous vasorelaxant in the liver and that effects of CO are at least in part cyclic GMP-dependent. It has also provided answers to many questions of hepatobiliary functions that had not been resolved because of the complexity introduced by the interplay between NO and CO.     

Gene Therapy in Infants with Severe Combined Immunodeficiency

Severe combined immunodeficiencies (SCID) are rare disorders that represent paediatric medical emergencies, as the outcome for affected patients can easily be fatal unless proper treatment is performed. The only curative treatment for SCID is reconstitution of the patient's immunity. For more than 30 years, allogeneic bone marrow transplantation (BMT) has been extremely successful for SCID. However, BMT often results in only incomplete restoration of B cell function in treated patients, especially when haploidentical donors are used. In addition, BMT can be associated with severe complications such as graft-versus-host disease (GVHD). Alternative forms of therapy for SCID are therefore desirable. Genetic correction of peripheral T lymphocytes and/or haematopoietic stem cells (HSCs) by retrovirally mediated gene transfer has been attempted for patients with SCID due to adenosine deaminase deficiency, the first genetic disease targeted in clinical gene therapy trials with very limited success, overall. After these pioneer trials, recent progress has led to significant improvement of gene transfer techniques and better understanding of HSC biology which has culminated in the recent success of a gene therapy trial for patients affected with X-linked SCID (X-SCID). In this trial, patients with X-SCID received autologous bone marrow stem/progenitor cells which had been retrovirally transduced with a therapeutic gene. Based on the current follow-up, the overall efficacy of this gene therapy procedure is to be considered similar to or even better than that achievable by allogeneic BMT, because patients were not exposed to the risks of GVHD. Although these exciting results have clearly demonstrated that gene therapy is a feasible therapeutic option for X-SCID, they have also raised important questions regarding the long-term outcome of this experimental procedure and the possibility of translating this success into applications for other forms of SCID.