Genetic diversity trend in Indian rice varieties: an analysis using SSR markers.

BACKGROUND: The knowledge of the extent and pattern of diversity in the crop species is a prerequisite for any crop improvement as it helps breeders in deciding suitable breeding strategies for their future improvement. Rice is the main staple crop in India with the large number of varieties released every year. Studies based on the small set of rice genotypes have reported a loss in genetic diversity especially after green revolution. However, a detailed study of the trend of diversity in Indian rice varieties is lacking. SSR markers have proven to be a marker of choice for studying the genetic diversity. Therefore, the present study was undertaken with the aim to characterize and assess trends of genetic diversity in a large set of Indian rice varieties (released between 1940-2013), conserved in the National Gene Bank of India using SSR markers. RESULT: A set of 729 Indian rice varieties were genotyped using 36 HvSSR markers to assess the genetic diversity and genetic relationship. A total of 112 alleles was amplified with an average of 3.11 alleles per locus with mean Polymorphic Information Content (PIC) value of 0.29. Cluster analysis grouped these varieties into two clusters whereas the model based population structure divided them into three populations. AMOVA study based on hierarchical cluster and model based approach showed 3 % and 11 % variation between the populations, respectively. Decadal analysis for gene diversity and PIC showed increasing trend from 1940 to 2005, thereafter values for both the parameters showed decreasing trend between years 2006-2013. In contrast to this, allele number demonstrated increasing trend in these varieties released and notified between1940 to 1985, it remained nearly constant during 1986 to 2005 and again showed an increasing trend. CONCLUSION: Our results demonstrated that the Indian rice varieties harbors huge amount of genetic diversity. However, the trait based improvement program in the last decades forced breeders to rely on few parents, which resulted in loss of gene diversity during 2006 to 2013. The present study indicates the need for broadening the genetic base of Indian rice varieties through the use of diverse parents in the current breeding program.

Efficacy and safety of fixed dose combination of Sitagliptin, metformin, and pioglitazone in type 2 Diabetes (IMPACT study): a randomized controlled trial.

BACKGROUND: Due to the progressive decline in ß-cell function, it is often necessary to utilize multiple agents with complementary mechanisms of action to address various facets and achieve glycemic control. Thus, this study aimed to evaluate the efficacy and safety of a fixed-dose combination (FDC) of metformin/sitagliptin/pioglitazone (MSP) therapy vs. metformin/sitagliptin (MS) in type 2 diabetes mellitus (T2DM). METHODS: In this phase 3, multicenter, double-blind study, patients with T2DM who exhibited inadequate glycemic control with HbA1c of 8.0-11.0% while taking ≥1500 mg/day metformin for at least 6 weeks were randomized to receive either FDC of MSP (1000/100/15 mg) or MS (1000/100 mg) per day for 24 weeks. The primary outcome measure was the change in HbA1c, and secondary outcomes included changes in fasting plasma glucose (FPG), postprandial plasma glucose (PPG), and body weight from baseline to 24 weeks along with safety and tolerability. RESULTS: Among the 236 patients randomized, 207 (87.71%) successfully completed the study. All baseline characteristics were comparable between the FDC of MSP and MS groups. There was a subsequent significant reduction of HbA1c in FDC of MSP (- 1.64) vs. MS (- 1.32); between groups was [- 0.32% (95% CI, - 0.59, - 0.05)], P = 0.0208. Similar reductions were found in FPG [- 13.2 mg/dL (95% CI, - 22.86, - 3.71)], P = 0.0068, and PPG [- 20.83 mg/dL (95% CI, - 34.11, - 7.55)], P = 0.0023. There were no significant changes in body weight. A total of 27 adverse effects (AEs) and one severe AE were reported, none of which were related to the study drug. CONCLUSION: The FDC of MSP demonstrated significant efficacy in managing glycemic indices and could serve as a valuable tool for physicians in the management of Indian patients with T2DM. TRIAL REGISTRATION: Clinical Trials Registry of India, CTRI/2021/10/037461.

Quality parameters of mango and potential of non-destructive techniques for their measurement - a review.

The king of fruits "Mango" (Mangifera indica L.) is very nutritious and rich in carotenes. India produces about 50% of the total world's mango. Many researchers have reported the maturity indices and quality parameters for determination of harvesting time and eating quality. The methods currently used for determination of quality of mango are mostly based on the biochemical analysis, which leads to destruction of the fruits. Numerous works are being carried out to explore some non-destructive methods such as Near Infrared (NIR), Nuclear Magnetic Resonance (NMR), X-ray and Computed Tomography (CT), electronic nose, machine vision and ultrasound for quality determination of fruits. This paper deals with some recent work reported on quality parameters, harvesting and post-harvest treatments in relation to quality of mango fruits and reviews on some of the potential non-destructive techniques that can be explored for quality determination of mango cultivars.

Alpha adrenergic-mediated accumulation of calcium in reperfused myocardium.

Reperfusion of ischemic myocardium is associated with increases in total myocardial calcium (Ca+2), which may influence the ultimate extent of ischemic damage as well as the development of arrhythmias. Since reperfusion is also associated with enhanced alpha-adrenergic responsivity, this study was performed to determine the potential interactions between alpha-adrenergic receptors and myocardial calcium during reperfusion. Cats were subjected to 35 min of left anterior descending coronary artery occlusion and 10 min of reperfusion. Total myocardial calcium was measured by atomic absorption spectrometry. Intracellular calcium was calculated from measurements of extracellular space [( 3H]inulin). In control animals with reperfusion, total calcium increased from 0.32 +/- 0.03 to 0.65 +/- 0.05 mmol/100 g dry tissue (P less than 0.0001), while intracellular calcium increased from 0.15 +/- 0.03 to 0.40 +/- 0.05 mmol/100 g dry tissue (P less than 0.001). Pretreatment with the alpha-adrenergic blocking agents phentolamine or prazosin prevented the increase in total and intracellular calcium. Phentolamine and the aqueous soluble alpha 1-adrenergic antagonist BE-2254 administered as late as 2 min before reperfusion similarly attenuated the increase in tissue calcium. Although administration of BE-2254 2 min before reperfusion failed to block the reperfusion-induced increase in extracellular space, the increase in calculated intracellular calcium was prevented. beta-Adrenergic blockade with propranolol partially attenuated but did not prevent an increase in total tissue calcium. Labetalol, a combined alpha- and beta-adrenergic blocking agent completely blocked the increase in tissue calcium during reperfusion. Additional experiments performed after 70 min of ischemia with reperfusion demonstrated a 49% attenuation of the increase in tissue calcium with alpha-adrenergic blockade. Electron microscopy with pyroantimonate and x-ray microprobe analysis demonstrated a large increase in calcium precipitate in mitochondria after reperfusion in untreated animals. Though alpha-adrenergic blockade prevented the calcium deposition in mitochondria, other criteria of ischemia persisted. Thus, alpha-adrenergic blockade specifically prevents the increase in intracellular calcium during reperfusion in reversibly injured tissue, independent of alterations in extracellular space and tissue water.

Squamous Cell Carcinoma of Skin after 20 Years of Renal Transplantation.

Solid organ transplant recipients are at high risk of developing malignancies due to the prolonged use of immunosuppressant drugs. Squamous cell carcinoma of skin can occur in these patients even after decades of organ transplant. A 45-year-old male underwent renal transplant for end-stage renal disease 23 years ago and was on immunosuppressive drugs since then. The patient was on regular follow-up. Three years back, he developed squamous cell carcinoma of both forearms and hands, which was treated with radiation therapy using 8 MeV electrons, by parallel opposed fields to a dose of 60 Gy/30 fractions. Complete response to treatment was achieved at 3 months posttreatment. The patient is currently on follow-up and asymptomatic for skin lesions. Hence, these patients require longer follow-up, active surveillance, and screening for early diagnosis and prompt treatment of the premalignant and malignant conditions.

Comparison of conventional fractionation (five fractions per week) and altered fractionation (six fractions per week) in stage I and II squamous cell carcinoma of oropharynx: An institutional study.

BACKGROUND: The radiotherapy (RT) dose and fractionation schedule for head and neck cancers for locoregional control and acceptable organ toxicity are still debatable. Accelerated RT includes administration of six fractions per week with the same dose per fraction. AIM: Comparison of conventional versus accelerated RT in terms of locoregional control, and acute and late radiation toxicity in squamous cell carcinoma oropharynx (stage I and II). SETTINGS AND DESIGN: Prospective, double arm, phase 2, randomized study. MATERIALS AND METHODS: Sixty patients of squamous cell carcinoma oropharynx (stage I and II) were randomized in two arms (accelerated fractionation, arm 1 and conventional fractionation, arm 2). All patients received RT dose of 66 Gray (Gy) in 33 fractions (#). The patients in arm 1 received six fractions per week with 2 Gy/# (Monday-Saturday) and in arm 2, five fractions per week with 2 Gy/# (Monday-Friday). No chemotherapy was administered. During and after the treatment, locoregional control, and acute and late radiation toxicity were assessed. RESULTS: At 1-year follow-up, 76% patients in arm 1 and 64% patients in arm 2 had complete response. The recurrence rate at the end of 1 year in arm 1 was 12% and it was 20% in arm 2.The acute Grade 2 and 3 toxicities were higher in the accelerated arm and no significant difference in late toxicities was found. SPSS version 4.0 was used for statistical analysis. CONCLUSION: Accelerated fractionation provides better locoregional control with higher but acceptable acute and equal late radiation toxicity in squamous cell carcinoma oropharynx.

Pattern of distant metastasis in molecular subtypes of carcinoma breast: An institutional study.

BACKGROUND: Molecular subtypes of carcinoma breast show a particular pattern of distant metastasis, the knowledge of which can help to diagnose and intervene early in the course of the disease. AIM: The aim of this study was to investigate and establish an association between the molecular subtypes of carcinoma breast and the pattern of distant metastasis. SETTINGS AND DESIGN: Single arm, retrospective study. MATERIALS AND METHODS: Totally 400 patients of carcinoma breast (Stage I and II) were selected who were treated between January 2010 and December 2013. All these patients were treated with the standard treatment protocol for breast cancer. The estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (HER-2) Neu status, and Ki-67 were done, and patients were classified into luminal A/B, HER-2 enriched, luminal/HER-2, and triple-negative subtypes. All patients were followed up until December 2015, and the pattern of local failure as well as distant metastasis was correlated with the molecular subtypes. RESULTS: A total of 143 patients developed distant metastasis and local recurrence. Bone was the most common site of metastasis overall. It was the most common type of metastasis in luminal A/B (53.3%) and luminal-HER (57.1%). Brain metastasis was most common in HER-2-enriched subtype (30.3%), whereas liver was the most common site of metastasis in HER-2-enriched subtype (45.45%). The incidence of brain metastasis was comparatively lower in luminal A/B subtype. Local recurrence was most common in HER-2-enriched subtype. The results were statistically significant for lung metastasis and local recurrence (with P = 0.004 and 0.047, respectively). CONCLUSION: A strong association exists between the molecular subtypes and the site of distant metastasis in breast cancer which can be used for greater vigilance to detect site-specific distant metastasis beforehand.

Sequential pulse defibrillation in humans: orthogonal sequential pulse defibrillation with epicardial electrodes.

A newly described sequential pulse technique, using four mesh electrodes positioned to approximate a true orthogonal system around the heart, was compared with a single pulse system using two of these same electrodes, which were located in positions that would be used for an automatic implantable defibrillator. The influence of electrode size was also assessed. The minimal energy necessary for defibrillation (defibrillation threshold) was determined intraoperatively in 21 volunteer patients undergoing accessory pathway ablation of Wolff-Parkinson-White syndrome. Ventricular fibrillation was induced with alternating current. Ten seconds after fibrillation onset defibrillation shocks were begun using either the single or the sequential pulse technique with stored voltage incremented until defibrillation was accomplished (defibrillation threshold). Selection of the use of a single or sequential pulse technique for the initial attempt was randomized. Defibrillation thresholds were determined in three groups of patients: 1) those with four small mesh electrodes (6 cm2), 2) those with two small and two large (13 cm2) mesh electrodes, and 3) those with four large mesh electrodes. In all cases, the average minimal energy needed for sequential pulse defibrillation was less than that required for single pulse defibrillation in the same patients with the same electrodes (four small, 24.8 +/- 24.7 J single versus 6.7 +/- 8.3 J sequential; two small plus two large, 11.4 +/- 15.0 J single versus 2.7 +/- 1.4 J sequential; four large, 8.1 +/- 5.3 J single versus 3.9 +/- 2.6 J sequential). Using the 6 cm2 electrodes for single pulse defibrillation energies delivered at greater than 45 J in two patients failed to defibrillate the heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Mode of onset of atrial fibrillation in the Wolff-Parkinson-White syndrome: how important is the accessory pathway?

The mode of onset of 103 episodes of atrial fibrillation lasting greater than or equal to 30 s was studied in 79 patients with the Wolff-Parkinson-White syndrome during electrophysiologic study. No patient had organic heart disease, and 31 had clinical atrial fibrillation before study. These 79 patients were then compared with a control group of 53 patients with Wolff-Parkinson-White syndrome in whom atrial fibrillation could not be induced. Ninety-five of the 103 episodes were technically suitable for analysis. Atrial fibrillation invariably began with rapid atrial tachycardia that became progressively disorganized within 10 to 20 cycles. It was initiated during right atrial stimulation (n = 52), right ventricular stimulation (n = 8), reciprocating tachycardia (n = 33) and spontaneously (n = 2). Most episodes started at a high right atrial site regardless of accessory pathway location, with only 19% of episodes starting at the electrode closest to the accessory pathway. During reciprocating tachycardia (n = 33), either atrial (n = 8) or ventricular (n = 5) extrastimuli initiated atrial fibrillation. Atrial fibrillation started at the accessory pathway site in 6 of 20 episodes occurring spontaneously during reciprocating tachycardia. Patients with atrial fibrillation had a longer PA interval (54 +/- 14 versus 42 +/- 12 ms, p less than 0.0001), shorter atrial functional refractory period (226 +/- 38 versus 240 +/- 30 ms, p = 0.049) and shorter anterograde effective refractory period of the accessory pathway (279 +/- 26 versus 304 +/- 75 ms, p = 0.03). Clinical reciprocating tachycardia was documented with equal frequency in both the atrial fibrillation and control groups (59.5% versus 52.9%, p = 0.58).(ABSTRACT TRUNCATED AT 250 WORDS)

Sensitivity and specificity of invasive and noninvasive testing for risk of sudden death in Wolff-Parkinson-White syndrome.

Invasive electrophysiologic testing and noninvasive testing were compared as methods for identifying patients with Wolff-Parkinson-White syndrome at risk for sudden death. Sixty-seven patients were studied, including nine with a history of ventricular fibrillation. Electrophysiologic testing, using the shortest interval between consecutive pre-excited beats (shortest RR interval) less than or equal to 250 ms during induced atrial fibrillation to define risk, identified seven of nine patients with previous ventricular fibrillation. The sensitivity increased to 87.5% if one patient with prior amiodarone therapy was excluded. Electrophysiologic testing had a specificity of 48.3% and a low predictive accuracy (18.9%) when using the shortest RR interval (less than or equal to 250 ms) to identify the risk for sudden death. Continuous pre-excitation after disopyramide (2 mg/kg body weight, intravenously) had a sensitivity of 71.4%, specificity of 26.1% and predictive accuracy of 12.8% for identifying patients with sudden death. Continuous pre-excitation during an exercise test identified these patients with a sensitivity of 80%, a specificity of 28.6% and a predictive accuracy of 11.8%. These noninvasive tests could also be used to predict the shortest RR interval observed during induced atrial fibrillation. Continuous pre-excitation on both tests used in combination had a sensitivity of 91.2%, a specificity of 66.7% and a predictive accuracy of 75.6% for predicting the shortest RR interval less than or equal to 250 ms. Thus, both invasive and noninvasive techniques have a good sensitivity but a low specificity for identifying patients with Wolff-Parkinson-White syndrome and sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effect of disopyramide on atrial fibrillation in the Wolff-Parkinson-White syndrome.

Disopyramide was administered intravenously to 54 patients during atrial fibrillation and predominantly pre-excited QRS configuration at the time of electrophysiologic study. All patients had Wolff-Parkinson-White syndrome and no patient had coexistent heart disease. The drug was given during sustained atrial fibrillation (n = 45) or during sinus rhythm before induction of atrial fibrillation for patients whose atrial fibrillation was self-terminating in the control state (n = 9). Atrial fibrillation converted to sinus rhythm within 15 min after disopyramide in 37 (82%) of the 45 patients. The shortest RR intervals between two pre-excited cycles increased from 208 +/- 42 to 293 +/- 117 ms (p less than 0.0001). The average RR interval of all cycles prolonged from 332 +/- 60 to 396 +/- 117 ms(n = 45, p less than 0.0001). The 9 patients in whom pre-excitation was abolished after the drug had a significantly longer initial shortest RR interval than that of the 36 patients in whom pre-excitation persisted (246 +/- 47 versus 199 +/- 36 ms, p = 0.0022). No patients developed significant hemodynamic or other adverse effects after disopyramide. These data support the intravenous use of disopyramide in patients with normal ventricular function who have atrial fibrillation and a predominant ventricular response over an accessory atrioventricular pathway.

Termination of acute atrial fibrillation in the Wolff-Parkinson-White syndrome by procainamide and propafenone: importance of atrial fibrillatory cycle length.

The effects of intravenous procainamide (n = 30) or propafenone (n = 25) were evaluated in 55 patients with acute atrial fibrillation and the Wolff-Parkinson-White syndrome. All patients received either procainamide (12 to 15 mg/kg body weight) or propafenone (1 to 2 mg/kg) during sustained (greater than 10 min) atrial fibrillation or after termination of nonsustained atrial fibrillation. Termination of atrial fibrillation was attributed to a drug if it occurred less than or equal to 15 min after infusion. Measurements included mean cycle length of fibrillatory electrograms (mean AA interval) as measured at the high right atrium and shortest RR interval between pre-excited cycles during atrial fibrillation. Atrial fibrillation terminated more frequently after procainamide administration (65%) than after propafenone (46%), although this difference was not significant. Procainamide prolonged the shortest pre-excited RR interval (228 +/- 41 to 339 +/- 23 ms, p = 0.0001) as did propafenone (215 +/- 40 to 415 +/- 198 ms, p = 0.0001) and the magnitude of increase was greater for propafenone (p = 0.048). Patients with sustained atrial fibrillation had shorter mean AA intervals than did their counterparts with nonsustained atrial fibrillation (123 +/- 25 versus 186 +/- 35 ms, p = 0.0001). Termination of sustained atrial fibrillation by either drug was accompanied by prolongation of the mean AA interval but not necessarily by the shortest pre-excited RR interval. Termination of atrial fibrillation was heralded by a 68% increase in the mean AA interval after procainamide administration compared with a 30% increase when the arrhythmia persisted. For propafenone the increases were 90% and 68%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

"Atypical" posteroseptal accessory pathway in Wolff-Parkinson-White syndrome.

The posteroseptal accessory pathway in the Wolff-Parkinson-White syndrome is associated with a delta wave that is negative in the inferior electrocardiographic (ECG) leads and the occurrence of the earliest retrograde atrial activation near the orifice of the coronary sinus during atrioventricular (AV) reentrant tachycardia. Seventy-two patients with a posteroseptal accessory pathway underwent epicardial mapping before operative ablation. The earliest epicardial activation occurred at the posterosuperior process of the left ventricle in all patients. Dissection of the posteroseptal region (right atrial-left ventricular sulcus) resulted in permanent loss of preexcitation in 69 patients and failure to abolish preexcitation permanently in 3. At reoperation in two patients, preexcitation was abolished by discrete cryoablation of the left side of the interatrial septum near the AV node approached through the atrial septum in the normothermic beating heart. At reoperation, one patient had extensive AV node dissection. All patients have had permanent loss of preexcitation. The vast majority of posteroseptal accessory pathways ("typical") are epicardial and ablated by dissection of the posteroseptal region. Rarely, posteroseptal accessory pathways are "atypical" in that they are intraseptally located near the AV node on the left atrial endocardial surface.

Comparison of the ventricular response during atrial fibrillation in patients with enhanced atrioventricular node conduction and Wolff-Parkinson-White syndrome.

Although ventricular fibrillation is a well known sequel to atrial fibrillation in the Wolff-Parkinson-White syndrome, ventricular fibrillation is not generally associated with supraventricular tachycardia in the presence of enhanced atrioventricular (AV) node conduction without pre-excitation. It was hypothesized that the ventricular response during atrial fibrillation may be less in patients with enhanced AV node conduction than in their counterparts with Wolff-Parkinson-White syndrome matched for anterograde effective refractory period. Slower ventricular rates during atrial fibrillation would suggest an increased propensity for concealed conduction in the enhanced AV node conduction group than in the group with an accessory pathway. Three groups of patients aged 16 to 65 years underwent electrophysiologic testing for supraventricular tachycardia or after surgical correction of Wolff-Parkinson-White syndrome. Sixteen patients had enhanced AV node conduction, 16 had Wolff-Parkinson-White syndrome and 16 had normal AV node conduction. Patients with enhanced AV node conduction and Wolff-Parkinson-White syndrome were well matched for anterograde effective refractory period (245 +/- 22 versus 258 +/- 25 ms) and minimal cycle length, maintaining 1:1 anterograde conduction (261 +/- 21 versus 260 +/- 40). There was no difference in intervals during atrial fibrillation (average RR interval = 372 +/- 37 versus 346 +/- 66) or shortest RR interval (266 +/- 27 versus 243 +/- 51). Thus, patients with Wolff-Parkinson-White syndrome and those with enhanced AV node conduction matched for anterograde refractory period exhibit similar ventricular rates during atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Right ventricular pressure during ventricular arrhythmias in humans: potential implications for implantable antitachycardia devices.

Implantable defibrillators use algorithms based on ventricular electrographic data to detect the onset and termination of arrhythmias, but these algorithms do not always differentiate hemodynamically stable from unstable arrhythmias. Although, ideally, left ventricular function should be used to assess the hemodynamic state, right ventricular pulse pressure can be assessed in humans on a long-term basis with a transvenous lead. The potential utility of right ventricular pulse pressure to assess hemodynamic stability was studied in 22 patients with induced ventricular arrhythmias. Right ventricular pressure was measured with use of a transvenous right ventricular endocardial pacing lead with a piezoelectric bender pressure sensor 3 cm from its tip. Single ventricular premature paced beats administered in up to a bigeminal frequency did not alter the mean right ventricular pulse pressure (control 33.7 +/- 26, bigeminy 35.7 +/- 26 mm Hg). Twenty-one episodes of induced ventricular tachycardia were studied in the electrophysiology laboratory. Five seconds after tachycardia induction, hemodynamically stable ventricular tachycardia had a longer cycle length (294 +/- 41 ms) and the right ventricular pulse pressure ratio was higher (0.55 +/- 0.26) than that in unstable ventricular tachycardia (cycle length 256 +/- 55 ms, p = 0.06; pulse pressure ratio 0.26 +/- 0.09, p less than 0.05). Twenty episodes of ventricular fibrillation were induced in eight patients. One second after induction, right ventricular pulse pressure decreased from 25 +/- 5 to 6 +/- 3 mm Hg (p less than 0.05). On the first beat after defibrillation, right ventricular pulse pressure increased to 24 +/- 14 mm Hg, a level not significantly different from that before the induction of ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

"Nodoventricular" accessory pathway: evidence for a distinct accessory atrioventricular pathway with atrioventricular node-like properties.

Two patients are described with recurrent pre-excited tachycardia and electrophysiologic characteristics typically ascribed to a nodoventricular accessory connection. The accessory pathway in each case demonstrated rate-dependent prolongation of conduction time and a low right ventricular insertion site; it was associated with a left bundle branch block configuration during pre-excitation. Intraoperatively, the pathway was demonstrated to originate at the anterior right atrioventricular (AV) anulus and not at the AV node. These data suggest that a "typical" nodoventricular pathway, by electrophysiologic criteria, may in fact be an AV pathway with AV node-like conduction properties and a distal right ventricular insertion site.

Cryosurgical modification of the atrioventricular node: a closed heart approach in the dog.

Intraoperative modification of the atrioventricular (AV) node to prolong refractoriness could be an alternative to His bundle ablation in patients with refractory supraventricular arrhythmias. It was postulated that a cryosurgical lesion at the posterior interatrial septum in the closed heart could achieve this. An electrophysiologic study was performed in anesthetized dogs. The AV fat pad was mobilized to expose the posteroseptal region. A cryoprobe cooled to 0 to -10 degrees C was moved in the exposed region until reversible AV block indicated proximity of the AV node. The probe was then cooled to -70 degrees C for 30 seconds. Four weeks later, five dogs had a favorable result with a mean prolongation of Wenckebach cycle length of 45 +/- 7% (p less than 0.05). Two dogs had complete heart block. Decreased (one dog) or increased (one dog) duration of freezing resulted in no change and complete heart block, respectively. Histologic examination verified partial damage to the AV node with preservation of the His bundle. Thus, controlled cryoinjury to modify AV node function is feasible in the closed heart; preservation of AV conduction provides an advantage over His bundle ablation.

Allergic contact dermatitis in patients with atopic dermatitis: A clinical study.

BACKGROUND: Atopic dermatitis (AD) is a chronically relapsing dermatitis with no known cure. Due to the chronic nature of the condition, frequent and long term topical therapy is used. This may lead to sensitization, resulting in allergic contact dermatitis (ACD). AIMS: The aim of the study was to observe the frequency of ACD in atopic patients in this part of the country using Indian standard battery. METHODS: A total number of 30 cases of AD were taken for the study. Diagnosis of AD cases was based on the criteria of Hannifin and Rajka (1980). All the selected cases of AD had mild to moderate grade of severity. All these cases were treated and patch tested during the remission period. The duration of the study was 12 months. RESULTS: Out of the 30 AD cases, 7 cases showed positive ACD with patch test allergens. CONCLUSION: This study shows that ACD is not uncommon amongst atopic individuals.

Intravenous adenosine triphosphate during wide QRS complex tachycardia: safety, therapeutic efficacy, and diagnostic utility.

PURPOSE: Inappropriate administration of intravenous verapamil to patients with wide QRS complex tachycardia due to ventricular tachycardia or atrial fibrillation with Wolff-Parkinson-White syndrome occurs frequently because of misdiagnosis, and may precipitate a cardiac arrest. We evaluated the safety and the diagnostic and therapeutic utility of adenosine triphosphate administered to a consecutive series of 34 patients during wide QRS complex tachycardia due to a variety of mechanisms. PATIENTS AND METHODS: Patients who had a hemodynamically and electrically stable, monomorphic, wide (greater than 120 msec) QRS complex tachycardia induced during an invasive cardiac electrophysiologic test were studied. Hemodynamic stability was defined by a systolic blood pressure greater than 80 mm Hg and no clinical evidence of cerebral or myocardial ischemia. Adenosine triphosphate, 20 mg, was administered as a rapid intravenous bolus via a peripheral vein during wide QRS complex tachycardia. Five surface electrocardiogram leads, at least three intracardiac electrograms, and blood pressure were monitored. RESULTS: Ventricular tachycardia was present in 14 patients (mean age 50.6 +/- 19 years, cycle length 326 +/- 67 msec) and adenosine triphosphate terminated the arrhythmia in one case. Ventricular tachycardia cycle length did not change. Among 10 patients with supraventricular tachycardia with mechanisms not involving the AV node (average ventricular cycle length 346 +/- 82 msec), one case of ectopic atrial tachycardia was terminated. The ventricular rate was transiently increased in patients with Wolff-Parkinson-White syndrome and atrial fibrillation (average R-R interval 351 +/- 84 msec in control and 317 +/- 82 msec after adenosine triphosphate, p less than 0.001). Reentrant tachycardias involving the AV node (cycle length 302 +/- 52 msec) terminated in seven of 10 patients. The drug was well tolerated, and no patient developed hemodynamic compromise necessitating cardioversion as a result of adenosine triphosphate. CONCLUSION: In the setting of electrophysiology testing, adenosine triphosphate is a safe agent, even when administered inappropriately during arrhythmias for which it is relatively ineffective, such as ventricular tachycardia, and Wolff-Parkinson-White syndrome with atrial fibrillation. It is an effective agent in terminating supraventricular tachycardia involving the AV node. Tachycardia termination following adenosine triphosphate, when used as a diagnostic test to indicate obligatory participation of the AV node, had a sensitivity of 70%, specificity of 92%, and a positive predictive accuracy of 85%. Thus, adenosine triphosphate also has diagnostic utility, but should be used after the appropriate arrhythmia diagnosis has been made based on the clinical history and analysis of the 12-lead electrocardiogram.

Comparative quantitative electrophysiologic effects of adenosine triphosphate on the sinus node and atrioventricular node.

A pharmacologic approach was used to characterize the sinus node (SN) and atrioventricular (AV) node responses to intravenous adenosine triphosphate (ATP) in 21 patients during electrophysiologic testing. ATP produced dose-dependent prolongation of spontaneous sinus cycle length. The mean maximal increase in sinus cycle length was 294 +/- 60 ms (n = 10). The mean dose of ATP required to produce this maximal sinus cycle length prolongation was 3.5 +/- 1.0 mg. The dose-response curve for sinus cycle length prolongation was sigmoid in shape with an EC50 of 0.39 mg derived from a median effect plot. There was a negative correlation between the control sinus cycle length and the dose of ATP required to produce the maximal prolongation of cycle length (p less than 0.05). In contrast, the mean dose of ATP producing AV block was 4.4 +/- 0.97 mg and the EC50 was 2.98 mg. There was a positive correlation between the AV nodal functional refractory period and the prolongation of the AH interval with a 2 mg dose (p less than 0.05). Consistent with the AV nodal dose-response curves, 8 mg ATP terminated paroxysmal reentrant supraventricular tachycardia at the AV node in 8 of 9 patients. Thus, SN and AV node responses to ATP have differences in their electrophysiologic correlates and EC50. These findings suggest that ATP has potentially different mechanisms of action on SN automaticity and AV nodal conduction that requires further investigation.