Role of reactive oxygen in phospholipase A2 activation by ischemia/reperfusion of the rat kidney

Purpose. To investigate the role of phospholipase A₂ (PLA₂) in reperfusion injury of the kidney in an in vivo animal model, renal mitochondrial PLA₂ activity was measured under three different conditions. Methods. Male Wistar rats (n = 72) anesthetized with pentobarbital underwent renal ischemia surgically for 45 min and were reperfused for the indicated time (renal ischemia/reperfusion). Treatments included reperfusion for various predetermined periods (phase 1), exposure to hyperbaric oxygen (phase 2), and administration of reactive oxygen species (ROS) scavenger (phase 3). Thereafter, each kidney was harvested, and mitochondrial PLA₂ activity was measured by a radioisotope technique. Results. Ischemia/reperfusion resulted in time-related PLA₂ activation in the renal mitochondria up to 48 h of reperfusion after renal ischemia. Renal mitochondrial PLA₂ activity was further augmented by hyperbaric oxygen exposure prior to reperfusion, whereas administration of the ROS scavengers suppressed mitochondrial PLA₂ activity. Conclusion. These data suggest that ROS may play an important role in the in vivo activation of PLA₂ associated with renal ischemia/reperfusion. Received for publication on July 6, 1998; accepted on November 30, 1998     

Factors relate to participation in medical checkups in a rural community an analysis including social network scores]

Since 1969, community-based stroke prevention programs have been conducted in N town, Kochi prefecture. To clarify factors related to participation in medical checkups including social networks, a cross-sectional questionnaire survey was performed on 6,704 residents aged 40 and over in N town in 1996. 1. Location of the workplace, types of medical insurance and interest in health were significantly associated with participation in medical checkups. 2. Participation in medical examinations provided at the workplace was significantly, inversely related with participation rates in community checkups in the group aged 40 to 59 years. 3. Low independence level in daily activities was inversely associated with participation rates for medical checkups in groups aged 60 years and older. 4. Visiting medical facilities was inversely associated with the participation rate for medical checkups in female groups. 5. The group with the highest social networks score (5 points) had the highest participation rate for medical checkups. After adjusting for other participation related factors, social networks scores had a significantly positive association with the participation rate for medical checkups provided by the Health Services for the Elderly Act.     

Expression of urokinase and urinary trypsin inhibitor in metastatic and non-metastatic murine Lewis lung carcinoma cells

The murine Lewis lung carcinoma 3LL cells give rise to spontaneous and experimental lung metastasis in C57BL/6 mice. Tumor cells maintained by serial subcutaneous transplantation in mice retain their ability to form lung metastasis, while cells carried in vitro loose metastatic potential with time. In order to obtain the non-metastatic subline, 3LL cells selected for its high lung colonization potential was grown continuously in vitro for 24 weeks. The present study was undertaken to characterize the expression of both urokinase-type plasminogen activator (uPA) and urinary trypsin inhibitor (UTI) in the non-metastatic (3LL(-)) and the metastatic (3LL(+)) cells. Both cells were tested on the Matrigel for invasive ability using a modified Boyden chamber and assayed for expression of uPA and UTI. The 3LL(+) cells secreted 5 times more uPA (6.25 mu g per 10(6) cells per 24 h) than the 3LL(-) cells (1.25 mu g per 10(6) cells per 24 h). The 3LL(+) cells, which expressed 2 times more cell-surface receptor-bound enzymatically active uPA (0.32 +/- 0.06 OD405) than the 3LL(-) cells (0.15 +/- 0.03 OD405), had larger amounts of cell-surface receptor-bound uPA. On the other hands, UTI levels in the conditioned media was decreased 25-fold in the 3LL(+) cells (0.05 mu g/10(6) cells/24 h) compared to the 3LL(-) cells (1.25 mu g/10(6) cells/24 h). The 3LL(-) cells expressed significantly higher levels of cell-associated UTI as indicated by a cell ELISA (3LL(+), 0.30 +/- 0.04 OD450; 3LL(-), 1.30 +/- 0.21 OD450) and by Western blot analysis. Metastatic competence in the 3LL(+) tumor model is associated with increased expression and release of uPA, as well as decreased UTI production, consistent with a more invasive phenotype. These data support our hypothesis that UTI may contribute to the inhibition of uPA expression in tumor cells.     

Delirious episodes induced by intravenous administration of clomipramine associated with an acute increase in its plasma concentrations

The aim of this paper is to describe two cases of clomipramine-induced delirium. One 61-year-old and one 67-year-old female depressive patients became delirious after beginning intravenous clomipramine injections in addition to their oral clomipramine administrations. Their plasma levels of both clomipramine and its metabolite, desmethylclomipramine, were acutely increased about twofold during delirium. The intravenous clomipramine administrations were discontinued. Their delirious state was gradually improved after stopping the intravenous clomipramine administrations. These findings suggest that acute increases of plasma levels of clomipramine and desmethylclomipramine after intravenous clomipramine injections might be related to the appearance of the delirious episodes.     

Advantages of stereotaxic aspiration of intracerebral hematoma using interventional magnetic resonance imaging: new surgical method

We describe the usefulness of stereotaxic surgery in the brain with special focus on aspiration of intracerebral hematoma using interventional MRI (0.3 Tesla; Hitachi, Japan). A 62-year-old female was admitted to our hospital with sudden right incomplete hemiparesis. A CT scan on admission showed a high-density mass in the left putamen. Soon after admission, her consciousness gradually decreased and the incomplete hemiparesis quickly worsened, so we promptly initiated an operation for stereotaxic aspiration of an intracerebral hematoma. During the surgery, real-time monitoring by MR-fluoroscopy depicted the gradual decrease of the hematoma. Postoperatively, her consciousness recovered to an almost alert level, but her right hemiparesis was unchanged. Stereotaxic aspiration of intracerebral hematoma using interventional MRI is advantageous because it enables accurate and safe evacuation of intracerebral hematoma in real time with no risk of irradiation during the procedure.     

How to conduct research of rare autoimmune diseases

Rare autoimmune diseases are difficult to conduct researches in spite of present era with advanced scientific progress. Research using genetic approach is a promising way since genetic findings implicate causality of diseases. Still, there are multiple obstacles preventing genetic studies of rare diseases. Here, we list up the problems and propose solutions for them with detailed examples. The biggest problem is that it is difficult to collect a substantial number of DNA samples from patients with rare diseases. We propose to collaborate not only with academic institutions and hospitals but with patients’ groups. Detailed examples include studies about Takayasu arteritis (TAK), relapsing polychondritis, and systemic sclerosis. In TAK, we identified IL12B, a key gene which seems to play a central role in the disease. After getting evidence of IL12p40 encoded by IL12B as a possible therapeutic target by showing similarities of the genetic background between TAK and ulcerative colitis, we performed a pilot clinical study of ustekinumab, a monoclonal antibody against IL12p40 for patients with refractory TAK and obtained good response. This is a good example of how genetic findings in a rare disease lead to development of new therapeutic option.     

The virulence factors and pathogenic mechanisms of Streptococcus pyogenes

Streptococcus pyogenes possesses a wide variety of virulence factors and can cause severe invasive infections. Most S. pyogenes express surface-located fibronectin-binding proteins as major invasion molecules. We identified 2 novel fibronectin-binding proteins (FbaA and FbaB) in S. pyogenes isolated from patients with severe invasive infection. Fba-deficient mutant strains showed significantly lower efficiency of invasion of human epithelial cells than that shown by an isogenic wild type strain. Furthermore, compared to mice infected with the isogenic wild-type strains, those infected with fba-deficient mutant strains showed decreased mortality. These findings suggest that Fba proteins are the causative agents for the development of severe invasive S. pyogenes infections.We know that few neutrophils migrate to S. pyogenes in severe streptococcal infection. We also found that complement C3b is degraded in the sera of patients with severe invasive S. pyogenes infections. Furthermore, it is now known that S. pyogenes SpeB is able to fragment neutrophil extracellular traps (NETs). SpeB appears to contribute to the escape of bacterial organisms from neutrophils by inactivating C3b and degrading NETs at the site of initial infection.Moreover, we have identified a C6-binding protein in cell-surface protein fractions from S. pyogenes. C6 is a component of the complement membrane attack complex (MAC). The C6-binding protein contributes to S. pyogenes evasion of the complement system by inhibiting MAC polymerization and bacteriolysis activity.We have confirmed that S. pyogenes is equipped with a wide variety of virulence factors to invade human tissue and escape from immunity.