Mice lacking EFA6C/Psd2, a guanine nucleotide exchange factor for Arf6, exhibit lower Purkinje cell synaptic density but normal cerebellar motor functions

ADP ribosylation factor 6 (Arf6) is a small GTPase that regulates various neuronal events including formation of the axon, dendrites and dendritic spines, and synaptic plasticity through actin cytoskeleton remodeling and endosomal trafficking. EFA6C, also known as Psd2, is a guanine nucleotide exchange factor for Arf6 that is preferentially expressed in the cerebellar cortex of adult mice, particularly in Purkinje cells. However, the roles of EFA6C in cerebellar development and functions remain unknown. In this study, we generated global EFA6C knockout (KO) mice using the CRISPR/Cas9 system and investigated their cerebellar phenotypes by histological and behavioral analyses. Histological analyses revealed that EFA6C KO mice exhibited normal gross anatomy of the cerebellar cortex, in terms of the thickness and cellularity of each layer, morphology of Purkinje cells, and distribution patterns of parallel fibers, climbing fibers, and inhibitory synapses. Electron microscopic observation of the cerebellar molecular layer revealed that the density of asymmetric synapses of Purkinje cells was significantly lower in EFA6C KO mice compared with wild-type control mice. However, behavioral analyses using accelerating rotarod and horizontal optokinetic response tests failed to detect any differences in motor coordination, learning or adaptation between the control and EFA6C KO mice. These results suggest that EFA6C plays ancillary roles in cerebellar development and motor functions.

Pallidin is a novel interacting protein for cytohesin-2 and regulates the early endosomal pathway and dendritic formation in neurons

Cytohesin-2 is a member of the guanine nucleotide exchange factors for ADP ribosylation factor 1 (Arf1) and Arf6, which are small GTPases that regulate membrane traffic and actin dynamics. In this study, we first demonstrated that cytohesin-2 localized to the plasma membrane and vesicles in various subcellular compartment in hippocampal neurons by immunoelectron microscopy. Next, to understand the molecular network of cytohesin-2 in neurons, we conducted yeast two-hybrid screening of brain cDNA libraries using cytohesin-2 as bait and isolated pallidin, a component of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) involved in endosomal trafficking. Pallidin interacted specifically with cytohesin-2 among cytohesin family members. Glutathione S-transferase pull-down and immunoprecipitation assays further confirmed the formation of a protein complex between cytohesin-2 and pallidin. Immunofluorescence demonstrated that cytohesin-2 and pallidin partially colocalized in various subsets of endosomes immunopositive for EEA1, syntaxin 12, and LAMP2 in hippocampal neurons. Knockdown of pallidin or cytohesin-2 reduced cytoplasmic EEA1-positive early endosomes. Furthermore, knockdown of pallidin increased the total dendritic length of cultured hippocampal neurons, which was rescued by co-expression of wild-type pallidin but not a mutant lacking the ability to interact with cytohesin-2. In contrast, knockdown of cytohesin-2 had the opposite effect on total dendritic length. The present results suggested that the interaction between pallidin and cytohesin-2 may participate in various neuronal functions such as endosomal trafficking and dendritic formation in hippocampal neurons. Cover Image for this issue: doi: 10.1111/jnc.14197.

Adiponectin Replacement Therapy Attenuates Myocardial Damage in Leptin-deficient Mice with Viral Myocarditis

The effects of adiponectin replacement therapy on myocardial damage were studied in leptin-deficient (OB) mice with acute viral myocarditis. Encephalomyocarditis virus was injected intraperitoneally into OB and wild-type (WT) mice. One subgroup of OB mice received no intervention and another subgroup received daily adiponectin replacement, simultaneously with viral inoculation. Differences in heart weight, cardiac histological score, numbers of infiltrating or apoptotic cells in the myocardium and the immunoreactivity of adiponectin receptors in myocytes were determined.

The reactivity of adiponectin receptor 1 in myocytes from OB mice on day 4 and day 8 after viral inoculation was significantly decreased compared with that in myocytes from WT mice; the OB mice also had elevated cardiac weights and severe inflammatory myocardial damage. Adiponectin replacement in OB mice inhibited the development of severe myocarditis by augmenting myocyte adiponectin receptor 1 reactivity. Exogenously administered adiponectin may inhibit the progression of viral myocarditis through binding to the adiponectin receptor 1 in leptin-deficient conditions.

Adiponectin, T-cadherin and tumour necrosis factor-alpha in damaged cardiomyocytes from autopsy specimens

This study determined the presence of adiponectin, T-cadherin (an adiponectin receptor) and tumour necrosis factor-alpha (TNF-alpha) in damaged myocytes from autopsied patients with acute or old myocardial infarction (MI) or dilated cardiomyopathy (DCM), using immunohistochemical staining. The enrolled patients included eight with acute MI, six with old MI and seven with DCM. Four autopsied individuals with no cardiac lesions were also enrolled as controls. Adiponectin and TNF-alpha were not observed in normal myocytes from control subjects, but T-cadherin was weakly detected. Immunoreactivity for adiponectin and T-cadherin was observed at the periphery of damaged myocytes from MI and DCM patients; intracellular reactivity for TNF-alpha was also seen. There were no statistically significant differences in the degree of reactivity for each molecule in the myocytes between the MI and DCM patients. These results suggest that the presence of adiponectin and TNF-alpha in damaged myocytes may contribute to the processes of myocardial injury occurring in MI and DCM.

Effect of the Serotonin Blocker Sarpogrelate on Circulating Interleukin-18 Levels in Patients with Diabetes and Arteriosclerosis Obliterans

We aimed to evaluate the effect of treatment with sarpogrelate, a serotonin 2A receptor antagonist, on circulating interleukin (IL)-18 levels in patients with diabetes and arteriosclerosis obliterans. Patients received sarpogrelate (100 mg 3 times daily) for 2 months. We evaluated the degree of cryaesthesia (a feeling of cold in the foot and toes) as the clinical outcome, and measured circulating IL-18, IL-6 and lipid protein concentrations. An improvement in clinical outcome occurred after initiation of sarpogrelate therapy;a significant decrease in IL-18 levels was observed after 2 months of therapy. Levels of IL-6 and lipid proteins, including triglyceride, total cholesterol and high-density lipoprotein cholesterol, were not significantly altered by treatment. Our data suggest that by reducing circulating IL-18 levels, sarpogrelate treatment may contribute to the inhibition of arteriosclerosis obliterans progression in patients with diabetes.

Panic Attack Symptoms in a Patient with Left Temporal Lobe Epilepsy

We describe a 56-year-old woman with left temporal lobe epilepsy who developed symptoms of a panic attack. Owing to normal electroencephalography and brain magnetic resonance imaging results, she was initially diagnosed as suffering from panic attacks and treated for anxiety neurosis. The symptoms persisted and she was re-examined in our department. An interictal electroencephalogram showed paroxysmal spike waves in the left mesial temporal lobe region and this was the basis for a diagnosis of left temporal lobe epilepsy. This report suggests that left temporal lobe epilepsy should be considered as the differential diagnosis when patients frequently complain of fear or anxiety.

Interleukin-6-Induced Reciprocal Expression of SERCA and Natriuretic Peptides mRNA in Cultured Rat Ventricular Myocytes

We investigated the effect of interleukin-6 (IL-6) expression on sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) mRNA levels in cultured rat neonatal ventricular myocytes. IL-6 plays a key role in regulating cardiac hypertrophy and the development of heart failure, and SERCA, ANP and BNP are all cardiac hormones with regulatory properties. Compared with baseline measurements, treatment with 50 U/ml IL-6 significantly decreased SERCA gene expression, but significantly increased ANP and BNP gene expression in the cardiac myocytes. These results suggest that the clinical overproduction of IL-6 in response to infection, autoimmune disease and cancer might be responsible for cardiac hypertrophy. Cardiac hypertrophy may result from the imbalance of both natriuretic peptides and SERCA transciption levels, caused by elevated IL-6 expression.

[Neoadjuvant chemotherapy for advanced gastric cancer with para-aortic lymph node metastasis]

Neoadjuvant chemotherapy was applied to patients with advanced gastric cancer and confirmed para-aortic lymph node metastasis. Subjects were 7 patients. The response to the neoadjuvant chemotherapy was a PR in 5 cases, MR in 2 cases for the primary lesion and CR in 2 cases PR in 5 cases for the para-aortic lymph node metastasis. The grades of histological response assessed on the resected specimen were Grade 0 in three cases, Grade 1a in one, Grade 1b in one and Grade 2 in two. While there was no significant difference in survival rate between patient groups with and without neoadjuvant chemotherapy, the 2-year survival rate in patients with neoadjuvant chemotherapy was a good 42.9%, compared with 10% in patients groups without neoadjuvant chemotherapy. It is concluded that a better prognosis can be expected for advanced gastric cancer patients with neoadjuvant chemotherapy.

Leukotriene D(4)-induced Rho-mediated actin reorganization in human bronchial smooth muscle cells

We investigated the role of cysteinyl leukotriene (CysLT) receptors on leukotriene D(4)-induced actin reorganization and the signaling pathways of the response in human bronchial smooth muscle cells. The effects of leukotriene D(4) on actin reorganization in human bronchial smooth muscle cells were evaluated by dual-fluorescence labeling of filamentous (F) and monomeric (G) actin with fluorescein isothiocyanate (FITC)-labeled phalloidin and Texas Red-labeled DNase I, respectively. Leukotriene D(4) (100 nM) induced actin reorganization in the presence and absence of extracellular Ca(2+). The CysLT type 1 (CysLT(1)) receptor antagonist ONO 1078 (4-oxo-8(-)[p-(4-phenylbutyloxy) benzoylamino]-2-(tetrazol-5-yl)-4H-1-benzopyran hemihydrate) inhibited leukotriene D(4)-induced actin reorganization. Pretreatment with pertussis toxin, C3 exoenzyme, or tyrosine kinase inhibitors significantly reduced leukotriene D(4)-induced actin reorganization. However, phosphatidylinositol-3-kinase and protein kinase C inhibitors had little effect on these responses. These results suggest that leukotriene D(4)-induced actin reorganization in human bronchial smooth muscle cells is extremely dependent on the CysLT(1) receptor coupled with pertussis toxin-sensitive G protein, Rho GTPases and tyrosine phosphorylation pathways.

Evaluation of renal function with 99mTc-MAG3 using semiautomated regions of interest

The need to draw regions of interest (ROIs) manually may reduce the convenience and reliability of estimating renal function from renal scintigraphy. We developed a semiautomated method to define ROIs for renal scintigraphy with 99mTc-mercaptoacetyltriglycine (MAG3) and evaluated the clinical applicability of the method to the estimation of renal function by camera-based methods.

METHODS

Dynamic renal scintigraphy with 99mTc-MAG3 was performed on 21 patients. An operator placed a large rectangular ROI over each kidney, a circular ROI within the liver, and a rectangular ROI between the kidneys. Using these ROIs, semiautomated renal ROIs were determined on the basis of the temporal changes in counts, in addition to the absolute counts, and a subrenal background ROI was automatically assigned for each renal ROI. Background-subtracted renograms were generated using these renal and subrenal ROIs, and renogram parameters were derived from the slope of the renogram and the area under the renogram. Clearance was calculated using the renogram parameters and equations determined previously with manual ROIs and correlated with clearance measured by a single-sample method. The relative function of the right kidney determined by the semiautomated method was compared with that determined by the manual method. Data processing was performed independently by another operator to assess interoperator reproducibility.

RESULTS

ROIs defined by the semiautomated method were visually judged to be acceptable for clinical use in all patients with a wide range of renal function. Clearance was successfully predicted with the semiautomated ROIs (r = 0.968 using the slope of the renogram; r = 0.934 using the area under the renogram), and relative function calculated with the semiautomated ROIs was almost identical to that calculated with manual ROIs. There was almost complete concordance in absolute and relative function between the two operators.

CONCLUSION

The semiautomated method can define ROIs for 99mTc-MAG3 renal scintigraphy with limited operator intervention. Camera-based methods using the semiautomated ROIs allow estimation of renal function with high accuracy and little interoperator variability and are suggested to be suitable for clinical use.

Airway responsiveness to acetylcholine in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs in vivo and in vitro

The characteristics of airway responsiveness to acetylcholine (ACh) in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs were clarified in vivo and in vitro. We measured the change in ventilatory mechanics in response to ACh inhalation by means of the bodyplethysmograph and the contractile responses of isolated trachea to ACh and carbachol (CCh). Further, muscarinic receptor subtypes involved these responses were identified. The basal values for ventilatory mechanics in BHS were not significantly different from those in BHR. Respiratory resistance to ACh was progressively increased in a time- and dose-dependent manner in BHS. The contractile responses of tracheal smooth muscle to ACh in BHS were significantly greater than those in BHR, but CCh-induced responses in BHS and BHR were similar. ACh- and CCh-induced contractions were mediated via M3 receptors. These results suggested that the falling-down of BHS in response to ACh inhalation was caused by the strong constriction of the airway and the reduction in ventilation. Moreover, the airway hyperresponsiveness to ACh in BHS might be partly dependent on the change in acetylcholinesterase activity.

[Study on anaerobic threshold in normal pregnant women]

We evaluated the anaerobic threshold (AT) in 104 normal pregnant women mainly in their second trimester. Each exercise testing was performed by using incremental bicycle ergometry at a pedal frequency of 60rpm while monitoring maternal heart rate, maternal blood pressure, minute ventilation (VE),oxygen uptake (VO2) and carbon dioxide output (VCO2) every 30 seconds. The AT was determined by estimating the point of departure from linearity of the plot of VE as a function of VO2. We could determine the AT in 100 cases (96.2%), and their AT values and the heart rates at AT point were 14.7 +/- 1.7ml/min/kg (mean +/- S.D.) and 128 +/- 12bpm, respectively. AT decreased significantly (p < 0.01) with the length of gestation, because of increased maternal body weight. The heart rate at the AT also declined significantly (p < 0.05) with gestational age, but it had no relation with maternal body weight. These results show that the maternal heart rate becomes hard to increase with gestational age, so that the maximal heart rate, as an index of exercise intensity during exercise should decrease with advancing gestational age.

[Follow-up study of hepatic hemangiomas]

Hepatic hemangioma is the most common benign tumor of the liver, but there are a few reports on chronological changes in size of hepatic hemangioma. To elucidate natural history of hepatic hemangioma, we evaluated consecutive ultrasonograms of 27 hemangiomas in 23 patients. Underlying liver disease in these 23 patients included seven cases with chronic hepatitis, five cases with liver cirrhosis and three cases with fatty liver. The remaining eight cases showed no evidence of liver disease. Follow-up period ranged 12 to 114 months (average 44). During the follow-up, six (22.2%) hemangiomas changed in size on US, which included three lesions with increase in size, one lesion with decrease in size and two lesions with spontaneous regression. Of 12 patients with chronic liver disease, only one patient showed significant change in the hemangioma size, which regressed spontaneously. These results showed that there was no case showing increase in size of hemangioma in patients with chronic liver disease. Thus, if clinically diagnosed hemangioma which tends to increase in size is detected on US or other imaging modalities in patients with chronic liver disease, aimed aspiration biopsy should be preferably performed considering the possibility of hepatocellular carcinoma.

Pulmonary neuroendocrine carcinoma in a four-month-old dog

A 4-month-old male Siberian Husky dog had a history of coughing, high fever and anorexia. Thoracic radiographs revealed increased radiographic density in the cranial and middle lobes of the right lung, with pleural effusion. Cytological examination of the pleural fluid suggested carcinomatous pleuritis. Right-side thoracotomy and resection of the cranial and middle lobes were performed. Histopathological examination of the resected tissue revealed an anaplastic large cell carcinoma. The tumour cells were positive for neuron specific enolase and also contained neuroendocrine granules. A particularly unusual feature of this case of pulmonary neuroendocrine carcinoma was the young age of the affected animal.

[Effect of exercise in water on maternal blood circulation]

To elucidate the effects of exercise in water on the maternal circulation, twenty normal pregnancies were examined under the following three conditions; 1) on the land at rest, 2) during water immersion and 3) after the exercise in water. Their gestational ages were from 25 to 37 weeks (31 +/- 4 weeks, mean +/- S.D., n = 20). We examined the blood pressure, the urine volume throughout the examination, CBC and the levels of vasopressin, plasma renin activity and human atrial natriuretic peptide (hANP). The blood volume calculated from the Hb and Ht were significantly (p < 0.001) increased during the water immersion (105.8 +/- 2.5%), even after the exercise (101.6 +/- 2.9%). Vasopressin was decreased during the water immersion and increased after the exercise, but plasma renin activity was decreased in these two conditions. The hANP concentration was significantly (p < 0.001) increased after the exercise in water and correlated with the urine volume (ml/hour) during the examination. These results show that the decline in blood pressure and the increase in the urine volume during the maternal swimming were caused by the decreased plasma renin activity and the increased hANP concentration resulted from the blood volume expansion during the exercise in water.

Methodological aspects of immunofluorescence applied to nephrology

The influences of different conditions of specimens and conjugates, especially of pretreatments on the fluorescent patterns of kidneys with positive staining for immunoglobulins were examined. The nature of immunoglobulins might be differentiated by the proper combination of pretreatments. It was also found that fluorescent patterns of kidneys were remarkably changed by different methodological conditions.

Concurrent feline immune-complex nephritis. Tubular antigen-positive and renal amyloidosis

We describe tubular antigen-positive immune-complex nephritis in a case of feline renal amyloidosis. Amyloid deposition was observed in mesangial area, and thickening of capillary walls was shown in the majority of the glomeruli. This case was also characterized with typical fluorescent granular depositions of cat IgG and C3 along the glomerular capillary walls as seen in human membranous glomerulonephritis. The fluorescent pattern of tubular antigen was identical with that of IgG and C3. Electron micrograph showed the thickening and irregularity of glomerular basement membranes, fusion of foot processes, and deposits of electron-dense or sometimes translucent materials, mostly in the intramembranous location. The causal sequence of the coincidental deposition of amyloid and immune complexes is discussed.

The application of immunofluorescence to the study of renal disease. I. Influences of various conditions of specimens and conjugates on the fluorescent patterns of kidney

Some basic problems in immunofluorescence were reexamined, limiting the object to kidneys. As to thickness of sections, 4 mum was demonstrated to be the most reasonable also to kidney specimens. Treatment of PBS for a short time before staining was recommended not only for cleanup effect but also for the possibility to disclose covered antigenic determinants. It was also established that fluorescent antibody with adequate F/P molar ratio, as well as with strict specificity, should be used, in order to prevent "false positives".

Some clinical and immunological aspects on contracted kidney in cats

With four clinical cases of contracted kidney in cats, granular to linear depositions of IgG and beta1C were demonstrated mainly in the capillary walls and mesangium of the glomeruli by means of immunofluorescence technique. The tubular basement membrane was also positive for cat IgG. These findings indicated that some immunological mechanisms might have been involved in the feline advanced renal lesions, as suggested in human cases. However, attempts were failed to detect some pathogenic agents for cats by immunofluorescence studies.