CHEMOPREVENTIVE EFFECT OF VITIS VINIFERA EXTRACT ON 12-O-TETRADECANOYL-13-PHORBOL ACETATE-INDUCED CUTANEOUS OXIDATIVE STRESS AND TUMOR PROMOTION IN MURINE SKIN

Vitis vinifera (grapes) is used as a fruit worldwide and known for its pharmacological properties. The present paper assesses the chemopreventive potential of Vitis vinifera against 12-O-tetradecanoyl-13-phorbol acetate (TPA)-mediated tumor promotion in 7,12-dimethyl-benz[a]anthracene (DMBA) initiated mice skin. Skin tumor initiation was achieved by a single topical application of DMBA (40 microg/animal/0.20 ml acetone) to mice. Two weeks after the initiation, promoting agent, TPA (5.0 microg/animal/0.2 ml acetone) was applied two times a week for 20 weeks. Pretreatment of Vitis vinifera 1h prior to each application of TPA resulted in protection against cutaneous tumorigenesis in dose-dependent manner. This inhibition was evident when tumor data was considered as the percentage of mice with tumor and the number of tumors per mouse. We have shown that typical application of Vitis vinifera prior to that of TPA resulted in significant inhibition against TPA-caused induction of epidermal ODC activity (P<0.001) and DNA synthesis. Application of Vitis vinifera at a dose level of 5.0 mg and 10.0 mg kg(-1) body weight in acetone prior to that of TPA treatment resulted in partial significant inhibition of oxidative stress in dose-dependent manner. The concomitant increase in the microsomal lipid peroxidation and xanthine oxidase activities were significantly reduced (P<0.001). In addition, the depleted level of glutathione and inhibited activities of antioxidant enzymes were recovered to the partial significant level. Hence, it can be suggested that Vitis vinifera can be used as a chemopreventive agent against oxidative stress and carcinogenesis.     

Sinus Rhythm Mapping in a Canine Model of Ventricular Tachycardia

The relationship between electrograms recorded during sinus rhythm and the activation sequence during ventricular tachycardia induced by programmed stimulation was investigated in a canine model of myocardial infarction. Thirteen dogs were studied 3 days (n = 10) or 14 days (n = 3) after coronary occlusion. Sixty-three unipolar electrograms were simultaneously recorded with a sock electrode array connected to a digital recording system, and analyzed by computer. Bipolar electrograms were recorded sequentially from the same sites with an analog recorder. Categories of unipolar electrograms were defined with reference to the QRS complex during sinus rhythm as follows: Class A included electrograms with an intrinsic deflection inscribed within the QRS complex, class B included those which did not exhibit any intrinsic rs deflection, and class C included those with an intrinsic deflection inscribed later than QRS. The epicardial distribution of each class of electrograms was significantly different between the preparations with, and those without inducible tachycardia (72% versus 63% of electrograms being in class A, 20% versus 35% in class B, and 8% versus 2% in class C; p less than 0.005). When tachycardia was inducible, class C epicardial electrograms were located in an area extending across the region of infarction, which corresponded to the common reentrant pathway of figure-of-eight patterns mapped during tachycardia. When ventricular tachycardia was not inducible, class B electrograms were recorded all over this region. The morphology of bipolar electrograms had no predictive value in identifying the common reentrant pathway. These results support the view that the inducibility of reentrant tachycardia is dependent upon critically located delayed activity detected during sinus rhythm by unipolar recordings.     

Ventriculoatrial Conduction Time During Bundle Branch Reentrant Beat Initiating Orthodromic Tachycardia: A Simple and Reliable Method for Localization of Accessory Pathways

VA Interval Via Accessory Pathway During Bundle Branch Reentry. Bundle branch reentrant (BBR) complex is commonly induced during programmed ventricular stimulation with single ex-trastimulus. In patients with atrioventricular accessory pathway, BBR beat frequently triggers orthodromic tachycardia. This study was designed to determine whether evaluation of the ventriculoatrial conduction time during BBR (VA_BBR) induced with right ventricular extrastimulation (i.e., left bundle branch block morphology) can separate left free-wall (LFW) accessory pathways from left posteroseptal (LPS) or right-sided pathways. Thirty-eight patients with single atrioventricular accessory pathways were included. There were 28 men and 10 women with a mean age of 26 years. The accessory pathway was localized in LFW in 23 patients (group I) and LPS in seven (group ID. Eight patients (group III) had pathways located in the right side. In each patient, VA_BBR was determined and compared with the following: (1) V₂A₂ interval exclusively via accessory pathway; and (2) ventriculoatrial conduction time during orthodromic tachycardia with narrow QRS complex (VA_NQ), left bundle branch block plus normal axis (VA_LB-NA) or left axis (VA_LB-LA). In group I, VA_BBR values (170–245 msec, mean 196.1 ± 20.5 msec) were 0–25 msec longer than V₂A₂ (170–245 msec, mean 191.3 ± 19.1 msec) and 45–125 msec greater than VA_NQ (100–155 msec, mean 125.6 ± 14.1 msec). VA_BBR was identical to VA_LB-LA but 25–55 msec greater than VA,_LB-NA (140–205 msec, mean 160.9 ± 20.8 msec). In group II, VA_BBR values (100–140 msec, mean 118.6 ± 14.3 msec) were 15–30 msec shorter than V₂A₂ (125–165 msec, mean 140.7 ± 14.3 msec) and 15–25 msec longer than VA_NQ (85–120 msec, mean 100.7 ± 12.0 msec). Comparing VA_BBR with VA_LB-NA or VA_LB-LA did not show any statistically significant difference. In group III, VA_BBR values were consistently shorter than V₂A₂ and identical to VA_NQ. Thus, assessment of VA_BBR is a simple and useful method that can be reliably utilized to differentiate LFW pathways from LPS or right-sided pathways. Furthermore, these data provide new insights into the electrophysiological characteristics of bundle branch reentry. (J Cardiovasc Electrophysiol, Vol. 1, pp. 121–131, April 1990)     

Signal Averaging in Patients withCoronary Artery Disease:

Late Potentials in CAD. In patients who have survived acute myocardial infarction, thepresence of ventricular late potentials using the high resolution signal-averaged KCG indicatesareas of slow conduction and delayed activation that may potentially serve as a substrate lormalignant ventricular arrhythmias. Although detection of late potentials is technique specific, signal-averaged analysis in the time or frequency domain may he a useful index for riskstratification with regard to ventricular tachycardia or sudden cardiac death. The sensitivityand specificity of late potentials for this purpose may he enhanced by comhination with othervariables, such as left ventricular ejection fraction and presence of complex ventricular ectopy, Therefore, the presence of ventricular late potentials in postmyocardial infarction patients, particularly in those patients with impaired left ventricular function, identifies those patienlswho are at high risk of malignant ventricular tachyarrhythmias, However., (he strategies forprevention of serious arrhythmia complications during follow-up need to be established, Thenegative predictive value of late potentials is very high. Thus, the absence of late potentialsindicates a low propensity to sustained ventricular tachycardia or sudden death, even in thepresence of complex ventricular ectopy. Interventions may therefore not be necessary orshould even he avoided, The incidence of late potentials in patients with spontaneous orinduced ventricular fibrillation is lower and, if present, less pronounced than in those with sustained monomorphic ventricular tachycardia. This presumably is due to a lower degree of conduction delay, which serves as a substrate for reentry. Therefore, the ability of the signal-aver-aged ECG to predict a propensity to ventricular fibrillation is limited, Despite these limitations, the signal-averaged ECG may be used as a risk predictor in evaluation of patients aftermyocardial infarction. Unfortunately, at least as far as time domain analysis is concerned, itcannot be used as an efficacy predictor for response to pbarniacologic interventions, Furtherstudies will determine whether other modes of signal-averaged analysis can predict theresponse to drugs.     

Unexpected Emergence of Manifest Preexcitation Following Transcatheter Ablation of Concealed Accessory Pathways

Preexcitation After Catheter Ablation. Introduction: The basis for anterograde or retrograde unidirectional block of accessory pathways still remains a controversial issue.
Methods and Results: Four of 19 consecutive patients (1 mule, 3 Female; ages 27 to 34 years) who underwent transcatheter ablation of concealed accessory pathways developed manifest preexcitation after the ablation. The location of the concealed accessory pathways in these four patients were right lateral, left posteroseptal, left posterolateral, and left lateral. Radiofrequency current was used in three of the four patients and high energy direct current in one patient. After ablation, manifest preexcitation was observed in these four patients for the first time. Manifest preexcitation developed immediately after ablation in two of the four patients and after 4 and 14 days in the other two. Detailed endocardial mapping revealed that the manifest preexcitation originated from the same location as the concealed pathways. Subsequently, catheter ablation was successfully performed in three of the four patients using radiofrequency current. One patient underwent successful surgical ablation. No recurrence of preexcitation was observed during a follow-up period of 9 to 38 months. All patients remained free of arrhythmias.
Conclusion: The basis for this unexpected emergence of preexcitation in these patients with only retrograde conducting accessory pathways deserves further investigation. Although not compared in the present study, this phenomenon has not been reported in patients who underwent surgical interruption of accessory pathways. We postulate that a lesion at the site of insertion of the accessory pathway had modified the anterograde conduction capacity.     

The prevalence of penoscrotal abnormalities and inguinal hernia in elementary-school boys in the west of Iran

AIM: We designed a cross-sectional study in order to determine the prevalence of inguinal hernia and penoscrotal abnormalities in the Lorestan province, situated in the west of Iran. METHODS: We studied 3205 elementary-school boys, aged 6-12 years, who underwent clinical examinations of the groin and genitalia in 2002. RESULTS: Abnormalities were detected in 213 children (6.64%). The most frequent anomaly was indirect inguinal hernia, seen in 78 children (2.4%). The other abnormalities were retractile testes in 39 boys (1.22%), undescended testes in 36 boys (1.12%), hydrocele in 28 boys (0.87%) and hypospadiasis in 25 boys (0.78%). Also, three children had micropenises, two had epispadiasis and another two boys had varicoceles. Ambiguous genitalia and apenia were not seen in the present series. Most of the parents were not aware of their children's anomalies (60.1%). CONCLUSIONS: Education of the public and medical staff about these abnormalities and screening system are needed to improve the outcome.     

Can mothers identify malnutrition in their children?

To assess mothers' perceptions about malnutrition and theirability to identify malnutrition in their own children, 339children aged 3–35 months and their mothers were studiedin two urban hospitals in Dhaka, Bangladesh, and in a communityclinic. The weight, height, and mid-upper arm circumferenceof the children were measured, and their mothers were interviewed.Child nutritional status according to their mother's statementand anthropometrically assessed nutritional status were compared.Sixty per cent of the mothers correctly identified better nutritionalstatus (weight/age >75% of NCHS median) and 67% mothers correctlyidentified malnutrition (weight/age < 75% of NCHS median)in their children. Sixty-one per cent of mothers with less than5 years of formal education correctly identified better nutrition(weight/age >75%) whereas 38% mothers with more than 5 yearsof education correctly identified better nutrition. Correctidentification of malnutrition was made by 70% of mothers withless than 5 years of formal education, and 74% of educated mothersdid the same. As regards causes of malnutrition, 33% of mothers stated thatlack of food at home resulted in undernutri-tion in their children(mean weight-for-age of these children was 65% of the NCHS median).Mothers' suggestions for improving child health were: betterfood in 31% cases; treatment of illnesses in 22% cases; andboth in 42% cases. The results suggest that most of the mothersare able to identify malnutrition in their children, and 95%of them are aware of ways to improve it, and that the provisionof adequate food and health care may improve child nutritionalstatus.