In vivo klotho gene transfer ameliorates angiotensin II-induced renal damage

The klotho gene, originally identified by insertional mutagenesis in mice, suppresses the expression of multiple aging-associated phenotypes. This gene is predominantly expressed in the kidney. Recent studies have shown that expression of renal klotho gene is regulated in animal models of metabolic diseases and in humans with chronic renal failure. However, little is known about the mechanisms and the physiological relevance of the regulation of the expression of the klotho gene in the kidney in some diseased conditions. In the present study, we first investigated the role of angiotensin II in the regulation of renal klotho gene expression. Long-term infusion of angiotensin II downregulated renal klotho gene expression at both the mRNA and protein levels. This angiotensin II-induced renal klotho downregulation was an angiotensin type 1 receptor-dependent but pressor-independent event. Adenovirus harboring mouse klotho gene (ad-klotho, 3.3x10(10) plaque forming units) was also intravenously administered immediately before starting angiotensin II infusion in some rats. This resulted in a robust induction of Klotho protein in the liver at day 4, which was still detectable 14 days after the gene transfer. Ad-klotho gene transfer, but not ad-lacZ gene transfer, caused an improvement of creatinine clearance, decrease in urinary protein excretion, and amelioration of histologically demonstrated tubulointerstitial damage induced by angiotensin II administration. Our data suggest that downregulation of the renal klotho gene may have an aggravative role in the development of renal damage induced by angiotensin II, and that induction of the klotho gene may have therapeutic possibilities in treating angiotensin II-induced end organ damage.     

Clinical features of eleven cases of Mycobacterium avium-intracellulare complex pulmonary disease associated with pneumoconiosis

The relationship between silicosis and tuberculosis is well known. Also other mycobacteria such as Mycobacterium kansasii often occur in association with pneumoconiosis. However, there are few reports describing an association of M. avium-intracellulare complex (MAC) lung disease and pneumoconiosis. The purpose of the present study is to describe clinical features of MAC respiratory infection associated with pneumoconiosis. Eleven patients with MAC respiratory infection associated with pneumoconiosis (all men, 6 with silicosis and 5 with welders' pneumoconiosis) were collected. A determination of whether or not MAC caused pulmonary disease was made using the 1997 criteria required by the American Thoracic Society. Radiologically, cavity formation as well as upper lung field predominance of MAC disease were observed in 8 of 11 cases (72.7%). Two of 11 patients died of respiratory failure. Our present study clearly demonstrates that clinical features of MAC respiratory infection associated with pneumoconiosis were different from MAC without underlying diseases.     

Lumbar spinal epidural arteriovenous fistula with perimedullary venous drainage after endoscopic lumbar surgery

Spinal epidural arteriovenous fistulas (AVFs) with perimedullary venous drainage are rare. This report describes a case of lumbar epidural AVF in a patient with a history of endoscopic lumbar discectomy at the same level 8 years prior to presenting with progressive myelopathy secondary to retrograde venous reflux into the perimedullary vein. A 69-year-old man presented with progressive lower extremity weakness and sensory disturbance and loss of sphincter control 8 years after endoscopic lumbar discectomy for a disc herniation at L4–5 level. Magnetic resonance imaging showed spinal cord edema and dilated intradural perimedullary vessels. Spinal angiography revealed an epidural AVF at the site of the previous endoscopic lumbar surgery with intradural perimedullary venous drainage. The fistula was successfully occluded via endovascular transarterial embolization, and the patient had stabilization of his neurological deficits. Lumbar spinal epidural AVFs, especially those associated with iatrogenic trauma, are rare. Endoscopic surgical procedure can occlude the epidural venous plexus and disturb venous drainage, thereby inducing local venous hypertension and leading to epidural AVF with perimedullary venous drainage. This type of pathology should be considered within the differential diagnosis of delayed neurological deterioration after spinal surgery.     

Role of PKA signaling in D2 receptor-expressing neurons in the core of the nucleus accumbens in aversive learning

The nucleus accumbens (NAc) serves as a key neural substrate for aversive learning and consists of two distinct subpopulations of medium-sized spiny neurons (MSNs). The MSNs of the direct pathway (dMSNs) and the indirect pathway (iMSNs) predominantly express dopamine (DA) D1 and D2 receptors, respectively, and are positively and negatively modulated by DA transmitters via Gs- and Gi-coupled cAMP-dependent protein kinase A (PKA) signaling cascades, respectively. In this investigation, we addressed how intracellular PKA signaling is involved in aversive learning in a cell type-specific manner. When the transmission of either dMSNs or iMSNs was unilaterally blocked by pathway-specific expression of transmission-blocking tetanus toxin, infusion of PKA inhibitors into the intact side of the NAc core abolished passive avoidance learning toward an electric shock in the indirect pathway-blocked mice, but not in the direct pathway-blocked mice. We then examined temporal changes in PKA activity in dMSNs and iMSNs in behaving mice by monitoring Förster resonance energy transfer responses of the PKA biosensor with the aid of microendoscopy. PKA activity was increased in iMSNs and decreased in dMSNs in both aversive memory formation and retrieval. Importantly, the increased PKA activity in iMSNs disappeared when aversive memory was prevented by keeping mice in the conditioning apparatus. Furthermore, the increase in PKA activity in iMSNs by aversive stimuli reflected facilitation of aversive memory retention. These results indicate that PKA signaling in iMSNs plays a critical role in both aversive memory formation and retention.Aversive stimuli induce not only rapid avoidance behavior, but also memory formation to escape from uncomfortable environments, and thus strongly influence animal behavior (1–3). The mesolimbic dopaminergic (DA) system plays a critical role in both rapid aversive reaction and memory formation (3–5). The nucleus accumbens (NAc) receives DA inputs from the ventral tegmental area (VTA) and serves as a key neural substrate for the control of aversive learning (6–8). The NAc consists of two subpopulations of medium-sized spiny neurons (MSNs) (9–11). The MSNs of the direct pathway (dMSNs) send their axons to the substantia nigra pars reticulata (SNr) and VTA, and selectively express dopamine D1 receptors, whereas the MSNs of the indirect pathway (iMSNs) indirectly project to the SNr and VTA via the ventral pallidum (VP) and predominantly express D2 receptors (12, 13). D1 receptors stimulate the cAMP-dependent protein kinase A (PKA) signaling cascade via Gs and exhibit a low affinity for DA (14–16). Conversely, D2 receptors inhibit the cAMP-PKA cascade via Gi and show a high affinity for DA (14–16). Thus, these two distinct types of MSNs, constituting two parallel pathways, contribute to the dynamic modulation of neuronal cell excitability and synaptic plasticity in the NAc circuitry (14–16).Although accumulated evidence indicates that DA modulation of the NAc is critical for both reward-based and aversive reactions (3, 5, 6, 17), the response of DA neurons in the VTA to aversive stimuli is not uniform; that is, some DA neurons are stimulated in response to aversive stimuli, whereas most others react by transiently suppressing their firing (18–22). Recent optogenetic studies have revealed that not only activation of iMSNs, but also inactivation of the VTA neurons, which down-regulates DA levels in the NAc, evoke an aversive reaction and learning (23–26); however, how intracellular cAMP-PKA signaling is involved in the induction and retention of aversive memory in a cell type-dependent manner in the NAc circuit remains largely elusive.In the present investigation, we addressed this issue using two approaches. We first used asymmetric reversible neurotransmission blocking (aRNB) techniques (27, 28), in which either the direct or indirect pathway at one side of the NAc was selectively blocked by the pathway-specific expression of transmission-blocking tetanus toxin and the other intact side was manipulated by injection of PKA inhibitors. In the second approach, we examined temporal changes in PKA activities of these two pathways in the formation of aversive memory by monitoring Förster resonance energy transfer (FRET) responses of PKA selective for either dMSNs or iMSNs with the aid of in vivo microendoscopic analysis (29, 30). These two different approaches explicitly demonstrated that the activation of PKA in iMSNs plays a key role in both the formation and the retention of aversive memory.     

Determinants of participation in prostate cancer screening: A simple analytical framework to account for healthy‐user bias

In Japan at present, fecal occult blood testing (FOBT) is recommended for cancer screening while routine population‐based prostate‐specific antigen (PSA) screening is not. In future it may be necessary to increase participation in the former and decrease it in the latter. Our objectives were to explore determinants of PSA‐screening participation while simultaneously taking into account factors associated with FOBT. Data were gathered from a cross‐sectional study conducted with random sampling of 6191 adults in Osaka city in 2011. Of 3244 subjects (return rate 52.4%), 936 men aged 40–64 years were analyzed using log‐binomial regression to explore factors related to PSA‐screening participation within 1 year. Only responders for cancer screening, defined as men who participated in either FOBT or PSA‐testing, were used as main study subjects. Men who were older (prevalence ratio [PR] [95% confidence interval (CI)] = 2.17 [1.43, 3.28] for 60–64 years compared with 40–49 years), had technical or junior college education (PR [95% CI] = 1.76 [1.19, 2.59] compared with men with high school or less) and followed doctors' recommendations (PR [95% CI] = 1.50 [1.00, 2.26]) were significantly more likely to have PSA‐screening after multiple variable adjustment among cancer‐screening responders. Attenuation in PR of hypothesized common factors was observed among cancer‐screening responders compared with the usual approach (among total subjects). Using the analytical framework to account for healthy‐user bias, we found three factors related to participation in PSA‐screening with attenuated association of common factors. This approach may provide a more sophisticated interpretation of participation in various screenings with different levels of recommendation.     

Nectin-4 expression contributes to tumor proliferation,angiogenesis and patient prognosis in human pancreatic cancer

Background

Nectin-4 belongs to the nectin family that has diverse physiological and pathological functions in humans. Recent studies have also suggested some roles for Nectin-4 in several human cancers. However, the precise roles and clinical relevance of Nectin-4 in tumors are largely unknown.

Methods

Nectin-4 expression was investigated in 123 patients with pancreatic cancer by immunohistochemistry. Furthermore, we investigated the association of Nectin-4 in pancreatic cancer with tumor proliferation, angiogenesis and immunity by using immunohistochemistry and siRNA interference method.

Results

Patients with high Nectin-4 expression had poorer postoperative prognosis than those with low expression. Importantly, multivariate analysis indicated that Nectin-4 expression had a significant independent prognostic value in pancreatic cancer (HR = 1.721, 1.085-2.730; P = 0.021). Tumor Nectin-4 expression was significantly correlated with Ki67 expression. In addition, siRNA-mediated gene silencing of Nectin-4 significantly inhibited the cell proliferation in human pancreatic cancer cells, Capan-2 and BxPC-3. Furthermore, Nectin-4 expression was also positively correlated with VEGF expression and intratumoral microvessel density. However, there were no significant correlations of tumor Nectin-4 expression with tumor-infiltrating T cells.

Conclusion

Nectin-4 is a significant prognostic predictor, and may play a critical role in pancreatic cancer. Nectin-4 may be novel therapeutic target for pancreatic cancer.     

Diffusion-weighted magnetic resonance imaging in oral and maxillofacial lesions: preliminary study on diagnostic ability of apparent diffusion coefficient maps

Objectives

The aim of this study was to investigate the usefulness of diffusion-weighted magnetic resonance imaging (DWI) in oral and maxillofacial lesions, especially the utility of apparent diffusion coefficient (ADC) maps for differential diagnosis of these lesions.

Methods

Fifty-seven patients who underwent magnetic resonance imaging for diagnosis of oral and maxillofacial lesions were included in this prospective study. DWI was performed on a 1.5 T unit with b-factors of 0 and 800 s/mm², and ADC maps were generated. ADC values were measured for all 57 oral and maxillofacial lesions (19 squamous cell carcinoma, 10 medication-related osteonecrosis of the jaw, 6 odontogenic abscess, 4 ranula, 4 osteoradionecrosis, 4 hemangioma, 3 pleomorphic adenoma, 3 odontogenic keratocyst, 2 nasopalatine duct cyst, 1 malignant melanoma, and 1 basal cell carcinoma).

Results

The mean ADC values for ranula (2.69 ± 0.59 × 10^?3 mm²/s) and nasopalatine duct cyst (2.34 ± 0.12 × 10^?3 mm²/s) were significantly higher than those for the other oral and maxillofacial lesions (p = 0.000). In contrast, the mean ADC value for odontogenic abscess (0.67 ± 0.36 × 10^?3 mm²/s) was significantly lower than those for the other oral and maxillofacial lesions (p = 0.000).

Conclusions

The present study suggests the usefulness of DWI in oral and maxillofacial lesions, especially the utility of ADC maps for differential diagnosis of these lesions.