Study of genetic divergence among wheat genotypes through random amplified polymorphic DNA

The degree of genetic divergence was estimated in seven wheat genotypes, six exotic genotypes and one local variety, through random amplified polymorphic DNA methodology. A total of 112 DNA fragments were generated by the 15 random primers, with an average of about 7.4 bands per primer. Among the 112, 50 fragments showed polymorphism among the seven wheat genotypes. Nei and Li’s similarity matrix ranged from 86.2 to 93.0%, which indicated a narrow genetic base among the genotypes. The maximum similarity, 93.0%, was observed between 12WLRG/1-12 and WL-43. The local variety, Chenab-70, showed the lowest similarity with the exotic types. We conclude that random amplified polymorphic DNA analysis can be used for the characterization and grouping of wheat genotypes; these results will be helpful in our wheat breeding program.

Acute and sub-acute effects of 2-butenoic acid-3-(diethoxy phosphinothioyl) methyl ester (RPR-II) on testis of albino rat.

Acute and sub-acute toxic effects of a novel phosphorothionate coded as RPR-II on testis of albino rats were studied. In acute study rats received a single dose of 12.3 mg/kg of RPR-II and sacrificed after 24 hr. For sub-acute study 0.58 mg/kg/day was administered orally to rats for 10 and 21 days. Acute exposure of rats to RPR-II brought no change either in the gonadosomatic index (GSI) or in the structure of testis or in the serum levels of testosterone. Testis glutathione (GSH) level and glutathione S-transferase (GST) activity was significantly decreased whereas, acid phosphatase (AcP) levels increased significantly at 24 hr post-treatment. On 7th day (withdrawal period) after the cessation of the treatment the GSH, GST, AcP, and AkP levels reached to near control. The sub-acute study revealed a significant decrease in GSI on 10th and 21st day of the treatment. In contrast, a time-dependent and significant increased in GSH level and GST activity was observed on 100th and 21st day of post-treatment, except GSH level on 10th day, which was declined. Due to RPR-II treatment the testis AcP and alkaline phosphatase (AkP) levels were significant at both 10th and 21st day of medication but AcP levels were increased whereas AkP levels decreased. The histopathological studies on day 10th showed considerable loss of spermatozoids in testis and at 21st day complete derangement of cellular organization was observed. Testosterone levels decreased significantly on 10th day and remained significantly low at 21st day. However, withdrawal studies showed a recovery in testis of rat treated with RPR-II. GST, GSH, GSI, AcP and AkP values recovered, testosterone levels were also well recovered but recovery in testis structure remained at a low profile. The present study suggests that RPR-II may cause testicular toxicity in rats affecting the normal functioning of testis and it also gave some new information in withdrawal studies.

A cardiac evoked response algorithm providing automatic threshold tracking for continuous capture verification: a single-center prospective study.

BACKGROUND: The AutoCapture algorithm as implemented in Regency and Microny pacemakers (Pacesetter Inc., Sylmar, CA, USA) provides beat-by-beat monitoring of capture based on proper detection of the evoked response, provides high output back-up pulse when loss of capture occurs, performs periodic threshold evaluations and acquires the capture threshold data in a time-based event counter for later retrieval. The safety and efficacy of this algorithm was prospectively evaluated at a tertiary care hospital of north India. METHODS AND RESULTS: Fifty-four patients (38 males, mean age 66+/-13 years) received a ventricular pacemaker model Regency SC+ with low polarization bipolar lead for high-grade atrioventricular block (n=42) and sick sinus syndrome (n=12). Evoked response and polarization signal were assessed initially at 24 hours postimplant, and follow-up measurements were systematically conducted at week 1 and months 1, 3 and 6. Further evaluation of eligible patients was performed at 6-monthly intervals. Lead implantation parameters were optimum in all patients. At 6 months, the algorithm was functional in 51 patients. The pacing threshold increased to 0.89+/-0.36 V (p<0.001) in the first month and stabilized thereafter. Significant saving of energy was accomplished by a constant output safety margin of 0.3 V instead of the traditional 100%. While the evoked response signal remained stable throughout the study period, the potential signal increased significantly from 0.6+/-0.7 mV to 1.0+/-0.6 mV (p<0.001) in the first month and remained steady subsequently. Back-up pacing in the event of exit block was confirmed in all 25 patients who underwent a 24-hour Holter test. Based on the suggested sense margins, ventricular undersensing was observed in 7 (28%) patients, the majority of whom had competitive cardiac rhythms. An elderly patient with pneumonic illness succumbed to pulmonary embolism at 6 months. CONCLUSIONS: This large single-center experience on AutoCapture demonstrates the success of this algorithm in low-energy ventricular pacing without compromising the patient's safety.

Study of Pseudomonas aeruginosa causing ventilator associated pneumonia.

Ps. aeruginosa is a frequent and prominent cause of nosocomial pneumonia especially in persons on assisted ventilation in the intensive care units. In a year long surveillance of ventilator associated pneumonia (VAP) we isolated 42 strains from broncho alveolar lavage samples collected and processed from 102 patients. By pyocin typing 40 of the 42 strains could be typed into 39 types but this designation changed each time the test was repeated. SDS-PAGE analysis of the whole cell proteins grouped the 42 strains of Ps. aeruginosa into 20 groups. After ribotyping, using an 18 mer DIG labelled oligonucleotide to the conserved region of 16S rRNA gene, the strains were designated into 18 types. The major type contained 8 isolates, but there was no clustering of isolates, indicating that each infecting strain was acquired separately and not from a common source. It would, therefore, appear that cross infection with a single clone was not the predominant mode of Ps. aeruginosa infection causing VAP in our ICU.

A preliminary study of fingerprinting of Pseudomonas aeruginosa by whole cell protein analysis by SDS-PAGE.

Forty two strains of Pseudomonas aeruginosa isolated from bronchoalveolar lavage fluid from intubated patients admitted to the Intensive care unit in AIIMS between December 1993 to June 1994 were included in the study. After obtaining typical biochemical profile, antimicrobial susceptibility was performed against ceftazidime, amikacin, gentamicin, ampicillin, cefotaxime and ciprofloxacin. Pyocin typing of these 42 strains was performed by scrape and streak method using 22 indicator strains. Forty strains could be typed showing excellent discrimination but on repeated testing the group designation changed indicating that the system had low reproducibility. SDS-PAGE of whole cell protein profile indicated the presence of 45 protein bands of different molecular weights, individual isolates had 37 to 42 protein band ranging in molecular weight from 340 kDa to 14.3 kDa. On the basis of Dice index of similarity the strains could be grouped into 20 types. Since all strains could be typed, the system has adequate typability. Similar results were obtained on repeated testing indicating good reproducibility.