Effects of granulocyte colony-stimulating factor upon coxsackievirus B3 myocarditis in mice

Granulocyte colony-stimulating factor is a potent activatorof mature granulocytes, and subsequently enhances superoxiderelease. The purpose of this study was to investigate the effectsof granulocyte colony-stimulating factor upon murine coxsackievirusB3 myocarditis in relation to free radical-mediated cardiacdamage. Two-week-old, male, C₃H/He mice were inoculated intraperitoneallywith coxsackievirus B3. Gramulocyte colony-stimulating factor20 µg.kg^–1. day^–1, polyethylene glycol-conjugatedsuperoxide dismutase (an enzyme catalyzing the conversion ofO₂^- to H₂O₂) 1 x 10³ U.kg^–1 day^–1 and granulocytecolony-stimulating factor 20 µg. kg^–1 day^–1,plus polyethylene glycol-conjugated superoxide dismutase 1 x10³ U.kg^–1. day^–1, were injected subcutaneouslydaily on days 0 to 14. Treated groups were compared to the infected,untreated group. The survival rate in the polyethylene glycol-conjugatedsuperoxide dismutase group was higher than that of the untreatedgroup on day 14, but on day 7, cardiac pathology was not significantlydifferent among the four groups. On day 14, the scores of cellularinfiltration, myocardial necrosis and calc were lower in thepolyethylene glycol-conjugated superoxide disnuitase group andin the granulocyte colony-stimulating factor plus polyethyleneglycol-conjugated superoxide dismutase group than in the untreatedgroup. The myocardial virus titres on days 7 and 14 did notd sign y among the four groups. The number of total white bloodcell and neutrophil counts were signifIcantly greater in thegranulo cyte colony-stimulating factor group than in the untreatedgroup on day 7. Taken altogether with the previous reports andpresent evidence that the administration of granulocyte colony-stimulatingfactor did not exacerbate coxsackievirus B3 myocarditis, itmay be that oxygen-free radicals appeared to be derived notfrom leukocytes but from other components in this experimentalmodel of myocarditis, whereas the myocardium was inflamed withleukocytes.     

Urinary uric acid excretion in term and premature infants

Objective : To clarify postnatal changes in urinary uric acid (UA) excretion in normal term infants and to examine the effects of prematurity or illness on the UA excretion.
Methodology : Measurements of urinary UA were performed in term and premature infants at the ages of 1 and 7 days and at 1 and 4 months, as well as at 7 months in term infants.
Results : Urinary UA levels were lowest on day 7 in term infants. The levels were highest on day 1 in premature infants and remained significantly higher compared to term babies during the first month of life. Respiratory failure requiring ventilation and oxygen supply resulted in further significant elevation of urinary UA in premature infants.
Conclusions : With the reference values obtained in the study reported here, urinary UA can now be used for the diagnosis and monitoring of inherited disorders of purine metabolism and for the assessment of oxygen radical insult to sick infants.     

Atrioventricular Nodal Physiology After Slow Pathway Ablation

The A V nodal physiology before and 1 week after “slow pathway potential” guided catheter ablation was examined in 32 patients with AV nodal reentrant tachycardia. A mean of 4.9 applications of radiofrequency energy eliminated AV nodal reentrant tachycardia in all patients. There were no significant differences in sinus cycle length (815 ± 159 msec vs 813 ± 162 msec;P = NS) and fast pathway conduction properties before and 1 week after ablation. Slow pathway conduction was completely eliminated in 10 (31%) (group I) of 32 patients after ablation. In the remaining 22 patients residual slow pathway conduction associated with one AV node echo was observed. In 15 patients (47%) (group II), the effective refractory period of the slow pathway showed a change of < 30 msec (265 ± 51 vs 266 ± 51 msec; P = NS), and in 7 patients (22%) (group III), a prolongation of more than 80 msec (247 ± 56 vs 340 ± 42 msec; P = 0.0001) before and 1 week after ablation. Minimal and maximal A₂-H₂ interval over the slow pathway in group II was not significantly changed (Min A₂-H₂:241 ± 37 vs 247 ± 40 msec; P = NS, Max A₂-H₂: 346 ± 79 vs 350 ± 60 msec; P = NS), while a significant prolongation was measured in group III (Min A₂-H₂: 261 ± 53 VS 373 ± 107 msec; P < 0.01. Max A₂-H₂: 359 ± 41 vs 427 ± 63 msec; P < 0.05) before and after ablation. Conclusion: In group II patients there was no evidence shown of impairment of the slow pathway. This suggests that disruption of the link between fast and slow pathways may be responsible for the elimination of AV nodal reentrant tachycardia, besides the elimination or impairment of the slow pathway itself, in “slow pathway potential” guided catheter ablation, and that the slow pathway potential may not necessarily represent activation of the slow pathway itself or of its atrial connection.     

Colonic Angiomyolipoma

Abstract: Angiomyolipoma is a rare benign tumor which usually occurs in the kidney with tuberous sclerosis. We encountered a case of angiomyolipoma of the cecum not associated with tuberous sclerosis. To our knowledge, this is only the third case reported in the international literature.     

Optimal Target Site for Slow AV Nodal Pathway Ablation

INTRODUCTION: Although a variety of ablation techniques have been developed in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT), there have been few reports discussing the location of the optimal target site. Based on our early experiences, we hypothesized that radiofrequency (RF) current applied around the upper margin of the coronary sinus ostium (UCSO) results in the most effective and safe treatment of AVNRT. METHODS AND RESULTS: To confirm our hypothesis, the efficacy of RF currents applied around the UCSO guided by local electrograms in 59 patients (group B: predetermined focal mapping approach) were compared with the outcomes in 60 other patients previously treated with the standard electrogram-guided mapping method starting around the lower margin of the coronary sinus ostium (group A). The precise location of ablation catheters at successful sites (S) was also evaluated. All the patients were successfully treated without complications. Significantly fewer RF pulses and lower energies were needed in group B patients (mean RF applications: 4.3 vs 1.4 applications, mean total energy delivered: 4,699 vs 2,236 J in groups A and B, respectively, P < 0.01). Detailed analyses of the anatomical locations of S using CS venography in group B patients who received only a single RF application (46 patients) revealed that the distance between His and S varied according to the length of Koch's triangle, while that between S and UCSO was relatively constant. In 85 % of these 46 patients, S was located within 5 mm above and below the level of the UCSO. CONCLUSION: RF applications around the UCSO guided by local electrograms yielded excellent outcomes in AVNRT patients with wide varieties in the size of Koch's triangle. The optimal target site was located within 5 mm above and below the level of UCSO along the tricuspid annulus.     

Suppression of contact sensitivity by local hyperthermia treatment due to reduced Langerhans cell population in mice

The effects of local hyperthermia treatment on contact sensitivity (CS) and on the number of Langerhans cells (LCs) were studied in mice. CS was significantly suppressed when mice were sensitized in the hyperthermia treated skin I, 2 or 4 days after treatment (43 degrees C for 45 min). This suppressive effect was not observed 7 or 14 days after the treatment. CS was also suppressed when mice were sensitized in non-treated skin I day after the treatment. The density of LCs detected as ATPase-positive cells also decreased significantly 1, 2, 4 and 7 days after the treatment. There appeared to be a positive correlation between the number of LCs and the extent of CS when mice were sensitized at hyperthermia treated skin. It was observed that this suppressive effect on CS was dose- and temperature-dependent. It could be transferred by spleen cells from the hyperthermia treated and DNFB-sensitized donors, and was antigen specific when spleen cells were transferred before sensitization of the recipient mice. This indicated it was, in part, associated with the induction of suppressor cells. These findings suggest that local hyperthermia treatment reduces the number of LCs with subsequent suppression of the induction phase of delayed-type hypersensitivity by the generation of antigen-specific suppressor cells.     

Catheter Ablation of Ventricular Insertion of Mahaim Fiber Using Noncontact Mapping System in a Patient with Mirror‐Image Dextrocardia

We report a case of mirror‐image dextrocardia with antidromic atrioventricular reciprocating tachycardia via the Mahaim fiber. Using the noncontact mapping system, arborized ventricular insertion of the Mahaim fiber was identified and successfully ablated. (PACE 2010; e102–e105)     

Renal functional measurements in young rats with chronic inhibition of nitric oxide synthase

The purpose of the present study was to examine renal functional changes caused by chronic blockade of nitric oxide (NO) synthesis in young rats. Two types of NO synthase inhibitor were used: N^G-nitro-L-arginine methyl ester (L-NAME) as a non-selective inhibitor and aminoguanidine (AG) as a selective inhibitor of the inducible isoform. Oral administration of L-NAME (20–80 mg/dL of drinking water), not AG (400 mg/dL), for 4 weeks induced systemic hypertension in the treated rats. Both inhibitors caused a significant reduction in urinary excretion of NO₂^?/NO₃^?. Rats treated with L-NAME developed proteinuria and tubular enzymuria (high excretion of N-acetyl-β-D-glucosaminidase) in a dose-dependent fashion, with normal serum levels of creatinine, albumin and cholesterol. Chronic AG administration did not alter the urinary levels of protein and N-acetyl-β-D-glucosaminidase or serum laboratory values. Overall, these observations highlight the importance of the continuous generation of NO by the constitutive isoform in the control of vascular tone and the maintenance of renal glomerular and tubular function. Oral administration of L-NAME may serve as a model of chronic NO-deficient hypertension with renal injury in young rats.