A new nonscanning confocal microscopy module for functional voltage-sensitive dye and Ca2+ imaging of neuronal circuit activity

Recent advances in fluorescent confocal microscopy and voltage-sensitive and Ca(2+) dyes have vastly improved our ability to image neuronal circuits. However, existing confocal systems are not fast enough or too noisy for many live-cell functional imaging studies. Here, we describe and demonstrate the function of a novel, nonscanning confocal microscopy module. The optics, which are designed to fit the standard camera port of the Olympus BX51WI epifluorescent microscope, achieve a high signal-to-noise ratio (SNR) at high temporal resolution, making this configuration ideal for functional imaging of neuronal activities such as the voltage-sensitive dye (VSD) imaging. The optics employ fixed 100- × 100-pinhole arrays at the back focal plane (optical conjugation plane), above the tube lens of a usual upright microscope. The excitation light travels through these pinholes, and the fluorescence signal, emitted from subject, passes through corresponding pinholes before exciting the photodiodes of the imager: a 100- × 100-pixel metal-oxide semiconductor (MOS)-type pixel imager with each pixel corresponding to a single 100- × 100-μm photodiode. This design eliminated the need for a scanning device; therefore, acquisition rate of the imager (maximum rate of 10 kHz) is the only factor limiting acquisition speed. We tested the application of the system for VSD and Ca(2+) imaging of evoked neuronal responses on electrical stimuli in rat hippocampal slices. The results indicate that, at least for these applications, the new microscope maintains a high SNR at image acquisition rates of ≤0.3 ms per frame.

Relationship between glomerular filtration rate and plasma N-terminal pro B-type natriuretic peptide concentrations in dogs with chronic kidney disease

Plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations increase in dogs with azotemia. However, the correlation between glomerular filtration rate (GFR) and NT-proBNP concentrations in dogs has not been evaluated. The objective of this study was to evaluate the correlation between GFR and plasma NT-proBNP concentrations in dogs with chronic kidney disease (CKD). In this retrospective cross-sectional study, plasma creatinine (Cre) and NT-proBNP concentrations, plasma iohexol clearance (PCio) values and blood pressure were measured in dogs with CKD. Dogs were classified according to PCio values into D group (dogs with decreased PCio values), and N group (dogs with normal PCio values). Dogs were further categorized on the basis of their systolic blood pressure and PCio values into NT-D group (normotensive dogs with decreased PCio values), NT-N group (normotensive dogs with normal PCio values), HT-D group (hypertensive dogs with decreased PCio values) and HT-N group (hypertensive dogs with normal PCio values). Significant correlations were observed between plasma NT-proBNP and Cre concentrations (r=0.360, P<0.05) and PCio values (r=-0.470, P<0.01). Plasma NT-proBNP concentrations were significantly higher in the D group than in the N group (P<0.001). Plasma NT-proBNP concentrations were significantly higher in the HT-D group than in the other three groups (P ≤ 0.007). No differences in plasma NT-proBNP concentrations were observed between the NT-D and HT-N groups (P=0.28). Plasma NT-proBNP concentrations were significantly lower in the NT-N group than in the other three groups (P ≤ 0.043). Our findings suggest that decreased GFR might be associated with increased plasma NT-proBNP concentrations in dogs, similar to that in humans. In addition, the complication of hypertension in CKD might be associated with further increases in plasma NT-proBNP concentrations. In conclusion, the effects of GFR and blood pressure on the plasma NT-proBNP concentration were small, but it could be necessary to consider the effects when this marker is used to evaluate canine cardiac disease.

Various patterns of traumatic triangular fibrocartilage complex tear

We demonstrate various patterns of traumatic triangular fibrocartilage complex (TFCC) tears including some atypical that cannot be categorized under Palmer's classification. TFCC traumatic tears in 173 wrists were examined arthroscopically or macroscopically and divided into disk tears (subdivided into four types: slit tear, flap tear, horizontal tear and tear within the distal radioulnar joint) and peripheral tears (subdivided into six types: ulnocarpal ligament tear, dorsal tear, radial tear, ulnar styloid tear, foveal tear and distal radioulnar ligament tear). Combinations of these types were found in 32 wrists. Wrist arthroscopy revealed various traumatic TFCC tears that do not come under Palmer's classification; therefore establishment of a new classification for traumatic TFCC tears seems to be warranted.

Relation of iodine-123 metaiodobenzylguanidine myocardial scintigraphy to endomyocardial biopsy findings in patients with dilated cardiomyopathy

BACKGROUND

Iodine-123 metaiodobenzylguanidine (123I-MIBG) concentrates in adrenergic neurons and has been developed for evaluation of the sympathetic nervous system. Recent studies have demonstrated that the normal heart is clearly visualized by 123I-MIBG cardiac scintigraphy, whereas abnormal 123I-MIBG myocardial uptake and washout have been demonstrated in patients after myocardial infarction and in patients with congestive cardiomyopathy, long QT syndrome, and ventricular tachycardia.

HYPOTHESIS

Based on evidence from recent studies, it can be hypothesized that 123I-MIBG uptake is related to histopathologic changes in the myocardium.

METHODS

The relation of 123I-MIBG uptake to the histologic findings for the heart was studied in 24 patients with dilated cardiomyopathy (DCM). The study group did not include patients with complicating disorders that primarily affect the adrenergic nervous system. The 123I-MIBG uptake was visually assigned one of four grades using the two criteria of the mean score for six regional uptake grades (mean score) and the global score obtained by visual evaluation of the entire image (global score). The 123I-MIBG uptake score was also determined for the region at which the biopsy specimen was obtained (biopsy region score). The histologic findings were evaluated by assigning one of four grades for each of the following five factors: myocyte hypertrophy, myocardial fibrotic change, myocyte degeneration and necrosis, mononuclear cell infiltration, and myocyte disarray. The sum for all grades was defined as the total score, and the global score was also assigned to the overall histologic findings.

RESULTS

All of the global, mean, and biopsy region scores for 123I-MIBG uptake correlated significantly with the global and total scores for the histologic findings. Among the histologic factors, myocyte degeneration showed score correlated with all global, mean, and biopsy region scores for the uptake. Myocyte hypertrophy was associated weakly with the 123I-MIBG uptake scores.

CONCLUSION

These results indicate that 123I-MIBG uptake imaging is associated with histopathologic abnormalities in patients with DCM.

Structure and functional analysis of wheat ICE (inducer of CBF expression) genes

Two different inducers of CBF expression (ICE1-like genes), TaICE41 and TaICE87, were isolated from a cDNA library prepared from cold-treated wheat aerial tissues. TaICE41 encodes a protein of 381 aa with a predicted MW of 39.5 kDa while TaICE87 encodes a protein of 443 aa with a predicted MW of 46.5 kDa. TaICE41 and TaICE87 share 46% identity while they share 50 and 47% identity with Arabidopsis AtICE1 respectively. Expression analysis revealed that mRNA accumulation was not altered by cold treatment suggesting that both genes are expressed constitutively. Gel mobility shift analysis showed that TaICE41 and TaICE87 bind to different MYC elements in the wheat TaCBFIVd-B9 promoter. Transient expression assays in Nicotiana benthamiana, showed that both TaICE proteins can activate TaCBFIVd-B9 transcription. The different affinities of TaICE41 and TaICE87 for MYC variants suggest that ICE binding specificity may be involved in the differential expression of wheat CBF genes. Furthermore, analysis of MYC elements demonstrates that a specific variant is present in the wheat CBF group IV that is associated with freezing tolerance. Overexpression of either TaICE41 or TaICE87 genes in Arabidopsis enhanced freezing tolerance only upon cold acclimation suggesting that other factors induced by low temperature are required for their activity. The increased freezing tolerance in transgenic Arabidopsis is associated with a higher expression of the cold responsive activators AtCBF2, AtCBF3, and of several cold-regulated genes.

Overexpression of TaVRN1 in Arabidopsis promotes early flowering and alters development

TaVRN1, a member of the APETALA1 (AP1) subfamily of MADS-box transcription factors, is a key gene that controls transition from vegetative to reproductive phase in wheat. The accumulation of TaVRN1 transcripts in winter wheat probably requires the down-regulation of TaVRT2, a MADS-box factor that binds and represses the TaVRN1 promoter, and of the flowering repressor TaVRN2. However, the molecular mechanisms by which TaVRN1 functions as an activator of phase transition is unknown. To address this, a combination of gene expression and functional studies was used. RNA in situ hybridization studies showed that TaVRN1 transcripts accumulate in all meristems and primordia associated with flower development. An interaction screen in yeast revealed that TaVRN1 interacts with several proteins involved in different processes of plant development such as transcription factors, kinases and a cyclophilin. Arabidopsis plants overexpressing TaVRN1 flower early and show various levels of modified plant architecture. The ectopic expression causes an overexpression of the AP1 and MAX4 genes, which are associated with flowering and auxin regulation, respectively. The induction of gene expression probably results from the binding of TaVRN1 to CArG motifs present on the AP1 and MAX4 promoters. In contrast, Arabidopsis plants that overexpress TaVRT2, which encodes a putative flowering repressor, show an opposite late flowering phenotype. Together, the data provide molecular evidence that TaVRN1 may have pleiotropic effects in various processes such as control of axillary bud growth, transition to flowering and development of floral organs.

TaVRT2 represses transcription of the wheat vernalization gene TaVRN1

In wheat, VRN1/TaVRN1 and VRN2/TaVRN2 determine the growth habit and flowering time. In addition, the MADS box transcription factor VEGETATIVE TO REPRODUCTIVE TRANSITION 2 (TaVRT2) is also associated with the vernalization response in a manner similar to TaVRN2. However, the molecular relationship between these three genes and their products is unknown. Using transient expression assays in Nicotiana benthamiana, we show that TaVRT2 acts as a repressor of TaVRN1 transcription. TaVRT2 binds the CArG motif in the TaVRN1 promoter and represses its activity in vivo. In contrast, TaVRN2 does not bind the TaVRN1 promoter and has no direct effect on its activity, but it can enhance the repression effect of TaVRT2. This suggests that a repressor complex regulates the expression of TaVRN1. In winter wheat, TaVRT2, TaVRN2 and TaVRN1 transcripts accumulate in the shoot apical meristem and young leaves, and temporal expression is consistent with TaVRT2 and TaVRN2 being repressors of floral transition, whereas TaVRN1 is an activator. Non-vernalized spring wheat grown under a short-day photoperiod accumulates TaVRT2 and shows a delay in flowering, suggesting that TaVRT2 is regulated independently by photoperiod and low temperature. The data presented suggest that TaVRT2, in association with TaVRN2, represses the transcription of TaVRN1.

Pathogenic mechanisms for parathyroid hyperplasia

Parathyroid hyperplasia is the cause of parathyroid gland enlargement in kidney disease (KD). Hypocalcemia, hyperphosphatemia, and vitamin D deficiency are critical contributors to the worsening of the hyperplastic parathyroid growth induced by KD. Reproduction of the features of human KD in the 5/6 nephrectomized rat model has shown that 80% of the mitogenic signals induced by KD in parathyroid cells that are aggravated by either high phosphate (P) or low calcium (Ca) diets occurred within 5 days after the onset of KD. Enhanced parathyroid expression of the potent growth promoter transforming growth factor alpha (TGFalpha) and its receptor, the epidermal growth factor receptor (EGFR), was identified as the main cause of parathyroid hyperplasia in experimental KD. Indeed, administration of highly specific EGFR-tyrosine kinase inhibitors (TKI), which block downstream signaling from TGFalpha-activated EGFR, completely prevented high P- and low Ca-induced parathyroid hyperplasia in early KD, as well as the severe progression of high P-induced parathyroid growth in established secondary hyperparathyroidism, the latter characterized by marked TGFalpha and EGFR overexpression in the parathyroid glands. More importantly, the suppression of signals downstream from TGFalpha binding to EGFR with EGFR-TKI treatment also revealed that TGFalpha self-upregulation in the parathyroid glands is the main determinant of the severity of the hyperplastic growth, and that enhanced TGFalpha activation of EGFR mediates the reduction in parathyroid vitamin D receptor levels thereby causing resistance to both the antiproliferative and parathyroid hormone-suppressive properties of calcitriol therapy.

Genistein inhibits Brca1 mutant tumor growth through activation of DNA damage checkpoints, cell cycle arrest, and mitotic catastrophe

Epidemiological studies revealed that amount of consumption of soy was inversely related to incidence of breast cancer. Genistein, the predominant isoflavone in soy, has been reported to reduce the incidence of breast cancer in animal models. To investigate whether genistein has a therapeutic effect on BRCA1-associated breast cancer, we treated Brca1 mutant mammary tumor cells with genistein. We showed that genistein treatment depleted the G1 population of cells, which was accompanied by an accumulation of cells at G2. Some genistein-treated cells entered mitosis; however, they exhibited chromosome abnormalities and maintained tetraploidy owing to abortive mitotic exit. A fraction of G2 cells underwent endoreduplication and became polyploid, which was accompanied by increased cell death through activating DNA damage response. Furthermore, our data indicated that Brca1 mutant cells were more sensitive to genistein than some other types of cancer cells, highlighting a good therapeutic potential of genistein for BRCA1-associated breast cancer.

Changes in coagulative and fibrinolytic activities in patients with intracranial hemorrhage

OBJECTIVE

To investigate whether any changes occur in the coagulative/fibrinolytic cascade in patients with subarachnoid hemorrhage (SAH) or hypertensive intracerebral hemorrhage (HICH).

DESIGN AND METHODS

Subjects included 143 patients with intracranial hemorrhage (SAH, n = 50; HICH, n = 82; ROSC-SAH [return of spontaneous circulation after cardiopulmonary arrest due to SAH], n = 11). Coagulative and fibrinolytic factors were measured in blood samples taken on admission.

RESULTS

The prothrombin fragment 1+2 level was significantly higher (p < 0.005) in SAH patients than in HICH patients. The fibrinolytic factors (plasmin alpha 2-plasmin inhibitor complex, D-dimer, or fibrinogen degradation products) in SAH and ROSC-SAH were both significantly higher than those in HICH, but the significance of difference was stronger in the case of ROSC-SAH (p < 0.05).

DISCUSSION

Both coagulative and fibrinolytic activities were altered after the onset of SAH. These results demonstrate that the coagulative/fibrinolytic cascade might be activated via different mechanisms in different types of stroke. It remains unclear, however, whether a significant alteration of the fibrinolytic cascade in patients with ROSC-SAH might be a nonspecific phenomenon attributable to the reperfusion after collapse.

Overexpression of aurora kinase A in mouse mammary epithelium induces genetic instability preceding mammary tumor formation

Aurora-A/STK15/BTAK, which encodes a centrosome-associated kinase, is amplified and overexpressed in multiple types of human tumors, including breast cancer. However, the causal relationship between overexpression of Aurora-A and tumorigenesis has not been fully established due to contradictory data obtained from different experimental systems. To investigate this, we generated a mouse strain that carries an MMTV-Aurora-A transgene. We showed that all the MMTV-Aurora-A mice displayed enhanced branch morphogenesis in the mammary gland and about 40% developed mammary tumors at 20 months of age. The tumor incidence was significantly increased in a p53(+/-) mutation background with about 70% MMTV-Aurora-A;p53(+/-) animals developed tumors at 18 months of age. Of note, overexpression of Aurora-A led to genetic instability, characterized by centrosome amplification, chromosome tetraploidization and premature sister chromatid segregation, at stages prior to tumor formation. Most notably, the severe chromosomal abnormality did not cause cell death owing to the activation of AKT pathway, including elevated levels of phosphorylated AKT and mammalian target of rapamycin, and nuclear accumulation of cyclin D1, which enabled continuous proliferation of the tetraploid cells. These data establish Aurora-A as an oncogene that causes malignant transformation through inducing genetic instability and activating oncogenic pathways such as AKT and its downstream signaling.

Ethyl esterification of docosahexaenoic acid in an organic solvent-free system with immobilized Candida antarctica lipase

Ethyl docosahexaenoate (EtDHA) is regarded as a potentially useful pharmaceutical substance on account of its beneficial physiological activities. We attempted the ethyl esterification of docosahexaenoic acid (DHA) in an organic solvent-free system using Candida antarctica lipase, which acts strongly on DHA and ethanol. Esterification of 88% was attained by shaking a mixture of DHA/ethanol (1:1, mol/mol) and 2 wt% immobilized C. antarctica lipase at 30 degrees C for 24 h. However, even in the presence of an excess amount of ethanol, the extent of esterification could not be raised above 90%. To attain a higher level of esterification, a two-step reaction was found to be effective. The first step was performed in a mixture of DHA/ethanol (1:1, mol/mol), and the reaction mixture was then dehydrated. In the second step, the resulting mixture was shaken at 30 degrees C for 24 h with 5 molar equivalents of ethanol against the remaining DHA using 2 wt% immobilized lipase. By means of this two-step procedure, 96% esterification was attained. Repetition of the first and second reactions showed that the immobilized lipase was reusable for at least 50 cycles. In addition, DHA remaining in the second-step reaction mixture was removed by a conventional alkali refining process, giving purified EtDHA with a high yield.

Enzymatic purification of polyunsaturated fatty acids

Polyunsaturated fatty acids (PUFAs) have various physiological functions. Of these, ethyl eicosapentaenoate is industrially purified and used as a medicine. Other PUFAs, such as docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), and arachidonic acid (AA), are also expected to be used as pharmaceutical agents; however, their industrial purification processes have not been established. Because PUFAs are highly unstable against heat and oxidation, we attempted to purify them by taking advantage of their enzymatic reactions. When free fatty acids (FFAs) originating from PUFA-containing oil were selectively esterified with lauryl alcohol (LauOH) using a lipase acting on a desired PUFA very weakly, the PUFA was efficiently enriched in the FFA fraction. In addition, when selective alcoholysis of ethyl esters originating from PUFA-containing oil with LauOH was carried out, the PUFA ethyl ester (EtPUFA) was enriched to a desired purity in the unreacted ethyl ester fraction. These reaction mixtures contain LauOH, PUFA (EtPUFA), and lauryl esters, and their molecular weights are different from one another. Hence, PUFA or EtPUFA can be easily separated by conventional distillation. Selective esterification increased the purity of DHA, GLA, and n-6 PUFAs rich in AA to 91, 98, and 96 wt%, respectively. Selective alcoholysis was also effective for increasing the purity of ethyl docosahexaenoate to 90 wt%.

Cervical intervertebral disc injury during simulated frontal impact

Cervical disc injury due to frontal impact has been observed in both clinical and biomechanical investigations; however, there is a lack of data that elucidate the mechanisms of disc injury during these collisions. The goals of the current study were to determine the peak dynamic disc annular tissue strain and disc shear strain during simulated frontal impact of the whole human cervical spine model with muscle force replication at 4 g, 6 g, 8 g and 10 g horizontal accelerations of the T1 vertebra. These data were compared with those obtained during physiological loading, and with previously reported rear impact data. Peak disc shear strain and peak annular tissue strain during frontal impact exceeded (p<0.05) corresponding physiological limits at the C2-C3 intervertebral level, beginning at 4 g and 6 g, respectively. These subsequently spread throughout the entire cervical spine at 10 g, with the exception of C4-C5. The C5-C6 intervertebral level was at high risk for injury during both frontal and rear impacts, while during frontal impact, in addition to C5-C6, subfailure injuries were likely at superior intervertebral levels, including C2-C3. The disc injuries occurred at lower impact accelerations during rear impact as compared with frontal impact. The subfailure injuries of the cervical intervertebral disc that occur during frontal impact may lead to the chronic symptoms reported by patients, such as head and neck pain.

Clinical success of Neoral absorption profile

We investigated the clinical benefits of cyclosporine microemulsion preconcentrate (CyA-MEPC; Neoral) in 16 de novo renal transplant recipients. The dose of CyA-MEPC was managed from AUC(0-4h), with serial target values of AUC(0-4h) at 5000-->4000-->3000-->2000 ng. hr/mL. The frequency of acute rejection episodes was 25%. The decreased renal function reached a low value of 12.5%, and creatinine was stable. Therefore, setting the target AUC(0-4h) value in the early phase at 5000 ng.hr/mL is an effective strategy to prevent acute rejection episodes. The single dose of Neoral given immediately after the renal transplant was 6 mg/kg (making a daily dose of 12 mg/kg). Thereafter, the dose-normalized AUC(0-4h) was set at a constant value to 4 weeks posttransplant. At week 4, the single dose was decreased to 4 mg/kg twice daily (a daily dose of 8 mg/kg). From these studies a daily dose of 12 mg/kg is suggested to be the appropriate amount for the first dose immediately after transplant. The renal biopsy performed at 6 months posttransplant showed neither cyclosporine-induced renal impairments, nor findings of chronic rejection, suggesting that 2000 ng.hr/mL is an appropriate target AUC(0-4h) value in the maintenance phase. These results suggest that it is possible to set the target value of C2 monitoring in the maintenance phase to a value slightly lower than that proposed from other studies.

DeltaFosB, but not FosB, induces delayed apoptosis independent of cell proliferation in the Rat1a embryo cell line

The fates of Rat1a cells expressing FosB and DeltaFosB as fusion proteins (ER-FosB, ER-DeltaFosB) with the ligand binding domain of human estrogen receptor were examined. The binding of estrogen to the fusion proteins resulted in their nuclear translocation and triggered cell proliferation, and thereafter delayed cell death was observed only in cells expressing ER-DeltaFosB. The proliferation of Rat1a cells, but not cell death triggered by ER-DeltaFosB, was completely abolished by butyrolactone I, an inhibitor of cycline-dependent kinases, and was partly suppressed by antisense oligonucleotides against galectin-1, whose expression is induced after estrogen administration. The cell death was accompanied by the activation of caspase-3 and -9, the fragmentation of the nuclear genome and cytochrome c release from the mitochondria, and was suppressed by zDEVD-fmk and zLEHD-fmk but not zIETD-fmk. The cell death was not suppressed by exogenous His-PTD-Bcl-x(L) at all, suggesting involvement of a Bcl-x(L)-resistant pathway for cytochrome c release.

Optical imaging of long-lasting depolarization on burst stimulation in area CA1 of rat hippocampal slices

Postsynaptic depolarization of dendrites paired with spike generation at the soma is considered to be a central mechanism of long-term potentiation (LTP) induction and a prime example of a Hebbian synapse. This pairing, however, has never been actually demonstrated on tetanic stimulation. Optical imaging of neural activity with a voltage-sensitive dye (VSD) is one potentially suitable method for examining this pairing. It is possible with optical recording to examine simultaneously the excitation of postsynaptic neurons at multiple sites. Thus the pairing of spike generation at the soma and dendritic depolarization can be examined with population level optical recording in highly laminar structures such as the hippocampal slice preparation. For example, one can correlate the optical signals obtained from cell layers with the activity of the soma, and, similarly, optical signals from stratum radiatum can be correlated with the activity of the apical dendrite, even though one cannot calibrate the optical signals in terms of actual membrane potential. Using the VSD aminonaphthylethenylpyridinium in rat hippocampal slices, we aimed to examine the pairing. Standard tetanic stimulation (100 Hz, 1 s) that elicited LTP in the field excitatory postsynaptic potential (fEPSP) resulted in a long-lasting depolarizing optical signal (about 2 s) that spread progressively along the known input pathway of CA1. The time course of this long-lasting depolarization was similar to that recorded intracellularly and to that reflected in the fEPSP. The long-lasting depolarization was insensitive to D,L-2-amino-5-phosphonovaleric acid (D,L-APV, 50 microM), but D,L-APV inhibited the induction of LTP; this allowed us to increase the signal-to-noise ratio of the optical signal by averaging several trials. Using this improved optical signal, we confirmed that postsynaptic cells practically "missed" spikes during tetanic stimulation in most parts of CA1, which had been suggested in the intracellular recordings. Intracellular recordings revealed a 23% reduction in input resistance, which might explain the failed spike generation at the soma via shunting. A steep spatial convergence of the depolarization along the transverse axis of area CA1 was observed. In contrast to the response resulting from a standard 100-Hz tetanus, broader activation, and paired depolarization with somatic spikes was observed on theta-burst stimulation. Overall we concluded that postsynaptic spike generation, at least in synchronous form, has less effect on LTP induction with standard tetanic stimulation, while theta-burst tetanic stimulation can elicit pairing of dendritic depolarization and somatic discharge.