Induction of immunoreactive proliferating cell nuclear antigen (PCNA) in goldfish retina following intravitreal injection with tunicamycin.

Effects of a photoreceptor-specific biotoxin, tunicamycin (TM), injected intravitreally into the goldfish eye at one side, were explored on electroretinograms (ERGs) and proliferating cell nuclear antigen-immunoreactive (PCNA-ir) nuclei, representing the mitotic activity of rod precursors, in the retina at both sides. The eye-cup preparations were made for ERG recording, and the retinas were isolated and processed as cryosections or wholemounts by a routine immunohistochemical method for visinin (cones), opsin (rods), tyrosine hydroxylase (dopaminergic cells) and proliferating cell nuclear antigen (PCNA), at various intervals after intravitreal injection with TM (1.0 micrograms/eye). On some thin sections, autoradiographic study was combined following intravitreal injection with [3H]thymidine (TdR, 0.1 microCi/eye). The dose of TM used heavily destroyed cones and rods only in the treated retinas 2-15 days after injection, the photoreceptors being renewed for further 15-20 days. Approximately in parallel, ERGs were largely impaired 2-10 days after TM injection and recovered for 10-20 days. However, intravitreal TM altered the distribution and density of PCNA-ir nuclei in both treated and untreated retinas. The density of PCNA-ir nuclei reduced at first (on days 1 and 2), and then clustered and rapidly increased on days 3-5 and maintained at high levels with diffuse distribution over the whole area, particularly in the treated retinas, up to 60 days after TM injection; the maximum peak of 3.7 and 20 times the initial level was seen on day 20 in the outer nuclear layer (ONL) and inner nuclear layer (INL), respectively. PCNA-ir nuclei were found to be abundant in the ONL even after the photoreceptors and ERGs had been restored in the treated retinas on day 20, suggesting a kind of overproduction of retinal cells. The autoradiographic study provided comparable results to those obtained with PCNA immunohistochemistry. The mechanism by which damage to the treated retina causes rod precursor cells to proliferate in the untreated retina remains unresolved.     

A case of transient bioprosthetic valve regurgitation and hemolysis devoloping early after surgery using Carpentier-Edwards valve.

The Carpentier-Edwards pericardial bioprosthesis has been markedly improved in the long-term results and valve-related complications including valve dysfunction, compared to the previous generation bioprosthesis. We report a patient in whom transient prosthetic valve regurgitation and hemolysis occurred early after mitral valve replacement using a Carpentier-Edwards pericardial bioprosthesis and were resolved by preservative therapy. The patient was a 77-year-old female diagnosed with severe mitral valve stenosis and insufficiency. She underwent mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis. Opening and closing of the three leaflets looked good on intraoperative transesophageal echocardiography (TEE). The only prosthetic valve regurgitation was evident at the central region where the leaflets form coaptation, and no abnormal findings were seen. Serum lactate dehydrogenase (LDH) was decreased to 405 U/l after surgery. However, LDH again began to increase on the 3rd day after surgery and it increased to 1,830 U/l on the 14th day after surgery. Hemolytic urine was detected on 10th day after surgery. PVL was not detected, but moderate abnormal regurgitation from the outside of the stent pocket was detected on TEE. Revision of valve replacement was considered, but LDH thereafter to 393 U/l on 41st day after surgery. The TEE was repeated, and only a trace of central jet was detected without abnormal regurgitation, unlike the previous examination. The patient did not develop any complications thereafter and was discharged on 47th day after surgery. LDH was nearly normal at the time of discharge.     

A case of giant hydronephrosis caused by renal fibrosarcoma

The presented report is fibrosarcoma arising from renal capsule in a 64-year-old woman. The tumor is very rare and is the 25th case in Japan. The patient visited our hospital with the complaint of macroscopic hematuria for several days. Abdominal examination revealed a painless lump from the left lumbar region to para-median abdomen. A diagnosis of hydronephrosis caused by neoplasma or tuberculosis was considered by CT, AG, etc., and transperitoneal nephrectomy was performed on 6-July-1984. Pathology of the tumor was fibrosarcoma arising from the renal capsule. Three months later, the tumor was growing on the peritoneal surface from the left renal region and she died on Nov. 10, 1984.     

The genotoxicity of UVA irradiation in Drosophila melanogaster and the synergistic action of 8-methoxypsoralen and UVA.

To study the genotoxicity of near-ultraviolet light (UVA) on a whole body, Drosophila melanogaster larvae were irradiated with UVA and the emerging flies were examined for the mutant wing spot formation. The genotoxicity of UVA was also assayed with the in vivo DNA-repair test using males with repair-deficiency at the mei-9 and mei-41 locus and the matching repair-proficient females. Third-instar larvae were placed in a plastic Petri dish, which was covered with soft glass, and irradiated with black light at 4-5 W/m2. This irradiation resulted in an increase in mutant wing-hair spots. After a 15 h irradiation (approximately 240 kJ/m2), the mutant clone frequencies found in the adult flies (spots/wing) were: 1.68 for the small single spots, 0.38 for the large single spots and 0.11 for the twin spots, while at zero time they were 0.68, 0.06 and 0.02 respectively. On the other hand, the UVA irradiation was negative in the in vivo DNA-repair test, indicating that the UVA-induced DNA lesion may not be subject to repair by the mei-9 and mei-41 functions. The presence of 8-methoxypsoralen (8-MOP) during the irradiation remarkably enhanced somatic mutations, and showed a strong DNA-damaging effect in the repair test. For example, a 15 h UVA irradiation with 26.7 microM 8-MOP resulted in a 14-fold increase in the number of twin spots per wing as compared with the frequency obtained on treatment with UVA alone. Treatment of the larvae with 8-MOP alone gave no mutant clones or DNA damage. A high frequency in twin spot formation was also observed in this UVA + 8-MOP treatment, indicating that extensive chromosomal recombinations took place in the somatic cells.     

Dendritic morphology of interstitial amacrine cells with monostratified dendrites in different-sized carp retinas.

The dendritic morphology of a class of interstitial (IS) amacrine cells in retinas of different-sized carp (body length, 9.1-32.3 cm) was investigated by identifying their fluorescent nuclei pre-loaded with 4,6-diamidino-2-phenylindole (DAPI), followed by iontophoretic injection of Lucifer yellow (LY) in isolated and formaldehyde-fixed flat-mounts under microscopic control. The LY-injected fusiform or pyriform cell bodies were found to locate at the middle of the inner plexiform layer (IPL) or immediately beneath the amacrine cell layer, and their dendrites monostratified in sublamina b of the IPL. The pyriform cells had a short stem from which extended 4-5 stout dendrites, while the fusiform cells extended similar dendrites from the soma. The dendrites of both types of cell were decorated with spines and a few long axon-like processes. The pyriform cells were found more frequently in smaller retinas than in larger retinas, suggesting that the former may migrate proximally during retinal growth. The dendritic field sizes of these IS amacrine cells were wider as the fish became larger, while the dendritic morphology, analyzed by the Sholl's branching model, was very similar in smaller and larger retinas. The results indicate that the IS amacrine cells do not add dendrites, but that their dendritic trees simply expand during retinal growth.     

Fecal stream is essential for adaptive induction of glucose-coupled sodium transport in the remnant ileum after total proctocolectomy

Our previous studies demonstrated that sodium glucose cotransporter 1 (SGLT-1) was induced in the remnant ileum of total colectomized rats via the action of factors other than hyperaldosteronism. The aim of the present study was to clarify whether fecal stream is required for the enhancement of SGLT-1-mediated sodium transport. Twenty-seven pairs of ileal tissues were obtained from the proximal and distal side, respectively, of loop ileostomy after total proctocolectomy. Mucosae were mounted in an Ussing chamber to evaluate glucose-coupled sodium transport. Levels of SGLT-1 mRNA in proximal and distal mucosae were compared by Northern blotting. Villous height and crypt depth were measured to test for correlations between mucosal structure and SGLT-1-mediated sodium transport or mRNA expression levels. Both glucose-coupled sodium transport and expression of SGLT-1 mRNA were significantly lower in distal mucosae relative to proximal mucosae. In distal mucosae, villous height, but not crypt depth, was significantly lower than in proximal mucosae, demonstrating a positive correlation between villous height and SGLT-1 function and expression. Comparative studies of proximal and distal mucosae demonstrated that in addition to hormonal changes, fecal stream is required for full induction of the sodium transport system (which includes SGLT-1-mediated transport) in the remnant ileum following total proctocolectomy. Presented in part at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–19, 2005 (poster presentation). This work was supported by Grants-in-Aid for Scientific Research 10557118 and 14657295 from the Ministry of Education, Science and Culture of Japan to K. Fukushima, and by Kanae Foundation to K. Fukushima.     

Two cases of thyroid metastases from renal cell carcinoma]

The identification and diagnosis of thyroid metastases from renal cell carcinoma are rare in living patients in spite of more frequent incidence during autopsy. We reported two cases of thyroid metastases from renal cell carcinoma. In both cases, histological examination revealed metastasis from renal cell carcinoma and negative immunohistological stain for thyroglobulin ruled out primary thyroid carcinoma.     

Changes in myocardial blood flow and systemic hemodynamics during hypotensive anesthesia induced by adenosine triphosphate with or without dipyridamole]

The changes in myocardial blood flow and systemic hemodynamics during hypotensive anesthesia with adenosine triphosphate (ATP) or ATP with dipyridamole (0.5 mg.kg-1) were studied in 20 mongrel dogs anesthetized with 0.7% halothane in 100% oxygen. In both groups, mean arterial blood pressure (MAP) was reduced to 60 mmHg by intravenous administration of ATP. During hypotensive anesthesia, coronary blood flow, myocardial blood flow and cardiac index increased significantly in both groups. Lactic acid and uric acid increased significantly during hypotensive anesthesia in the group 1. Heart rate, MAP, systemic vascular resistance and coronary vascular resistance decreased significantly during hypotensive anesthesia in both groups. Mean pulmonary arterial pressure, pulmonary arterial wedge pressure and central venous pressure showed no significant changes in both groups. Base excess in the group 1 increased markedly compared with the group 2. We conclude that pretreatment with dipyridamole can prevent metabolic acidosis that occurs during hypotensive anesthesia induced by ATP.     

Changes in Glucose Metabolism in Cerebral Cortex and Cerebellum Correlate With Tremor and Rigidity Control by Subthalamic Nucleus Stimulation in Parkinson's Disease: A Positron Emission Tomography Study

Objective. Employing [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET) to assess the correlation between the effect of deep brain stimulation (DBS) on the subthalamic nucleus (STN) and the regional cerebral metabolic rate of glucose (rCMRGlc) in advanced Parkinson's disease patients (N = 8). Materials and Methods. On the basis of patients’ diary records, we performed FDG‐PET during the off‐period of motor activity with on‐ or off‐stimulation by STN‐DBS on separate days and analyzed the correlation between changes in motor symptoms and alterations in the rCMRGlc. Result. When FDG‐PET was performed, the motor score on the unified Parkinson's disease rating scale (UPDRS) was 64% lower with on‐stimulation than with off‐stimulation (p < 0.001, Wilcoxon single‐rank test). STN‐DBS increased the rCMRGlc in the posterior part of the right middle frontal gyrus, which corresponded to the premotor area, and the right anterior lobe of the cerebellum (p < 0.005, paired t‐test). No region exhibited a decrease in rCMRGlc. Among the items of the UPDRS motor score, the changes in resting tremor and rigidity of the left extremities showed a significant correlation with the changes in rCMRGlc observed in the right premotor area (p < 0.02 and p < 0.05, respectively, Spearman's rank correlation). Conclusions. STN‐DBS either activates the premotor area or normalizes the deactivation of the premotor area. These FDG‐PET findings obtained are consistent with the idea that STN‐DBS modifies the activities of neural circuits involved in motor control.     

Glucocorticoid receptor enhancement of pregnane X receptor-mediated CYP2B6 regulation in primary human hepatocytes.

Although the glucocorticoid receptor (GR) facilitates the xenobiotic-induced expression of CYP2B in rodents, its role in the regulation of human CYP2B6 is unclear. In this report, the role of human GR in the regulation of CYP2B6 was evaluated using primary human hepatocytes and transfection assays with Huh7 cells. CYP2B6 expression was not induced in primary hepatocytes treated with dexamethasone (DEX) concentrations (0.01-1 microM) known to activate GR. In contrast, treatment with 0.1 microM DEX enhanced CYP2B6 induction by different pregnane X receptor (PXR) activators, including rifampin, phenytoin, clotrimazole, and phenobarbital. In Huh7 cells, cotransfection of human (h)GR and hPXR with CYP2B6-phenobarbital-responsive enhancer module (PBREM) reporter constructs revealed that all hPXR ligands induce CYP2B6 reporter gene activity, and this ligand-dependent activation is greatly enhanced by activated hGR. CYP2B6 reporter gene expression was not induced in the presence of hPXR ligands when hGR alone was cotransfected with CYP2B6 reporter construct. In hGR and human constitutive androstane receptor (hCAR) cotransfection assays, activated hGR increased the constitutive activation of PBREM reporter constructs by hCAR in the absence of inducers. In the presence of activated hGR and known inducers of CYP2B6, only PB treatment caused a further 2-fold activation of hCAR compared with control. These studies show that hGR is involved synergistically in the xenobiotic-responsive regulation of human CYP2B6 by hPXR and hCAR. Moreover, the results suggest that the GR-enhanced expression of CYP2B6 is mediated through an indirect mechanism that does not require increased expression of nuclear receptor.