Evaluation of four methods of DNA recovery from Mycobacterium avium subspecies paratuberculosis present in intestine tissue of goats and comparative sensitivity of IS900 PCR with respect to culture for diagnosis of Johne's disease

Low sensitivity of PCR reaction for detection of Mycoobacterium avium subspecies paratuberculosis (MAP) in tissues and fecal samples is mainly attributed to false negative results. Present study was undertaken to compare four methods of DNA isolation from tissues of infected animals and to determine most sensitive protocol for the recovery of DNA, suitable for IS900 PCR based detection of Johne's disease infection. Method I, the traditional van Soolingen2 method of DNA isolation was adopted for the isolation of DNA from tissues. Method II was modification (hexadecyl pyridinium chloride-HPC treatment) of van Soolingen2 method. Method III was traditional tissue DNA isolation method based on tissue lysis buffer. Method IV was modification of method III (HPC treatment). Using four methods of DNA isolation from 25 intestinal tissues of clinically infected goats, DNA was isolated from 15 (60.0%), 18 (72.0%), 13 (52.0%) and 13 (52.0%) tissues using method I, II, III and IV, respectively. All isolated DNA preparations were positive for MAP in IS900 PCR. HPC treatment enhanced the recovery of DNA from tissues of infected animals using method II. Therefore, method II can improve the diagnosis MAP infection using IS900 PCR.

Pathogenic ‘Bison-type’ Mycobacterium avium subspecies paratuberculosis genotype characterized from riverine buffalo (Bubalus bubalis) in North India

Despite low per-animal productivity of ruminants in developing countries, Johne's disease has not been investigated in buffaloes, which are primarily found in these countries. This is due to lack of expertise, diagnostic kits and priority to production diseases like Johne's disease. Presence of pathogenic Mycobacterium avium subspecies paratuberculosis (Map) was investigated by screening of target tissues (mesenteric lymph nodes and large intestine) by culture and IS 900 PCR, in 50 sacrificed buffaloes. Indigenous ELISA kit originally developed for goats and sheep was standardized in buffaloes and used to estimate sero-presence of Map in 167 serum samples representing population of buffaloes in Agra region of North India. In culture, 48.0% buffaloes were positive from 50 tissues each from mesenteric lymph nodes (34.0%) and large intestine (36.0%). IS 900 PCR was standardized using specific primers (150 C and 921) and 229 bp-amplified product was characteristic for Map. Of the 25 mesenteric lymph nodes, 40.0% were positive in IS 900 PCR. Genomic DNA from Map cultures was successfully amplified from all the 24 isolates (100.0%). Map was further genotyped as 'Bison type' using IS 1311 PCR-REA. Culture of tissues showed high presence of Map in target tissues, despite high culling rate in buffalos in view of high demand of buffalo meat. Specific tissue-PCR provided rapid confirmation of Map infection in sacrificed buffaloes. In tissue-PCR, all the cultures were positive as compared to 40.0% detected directly from tissues. ELISA kit using indigenous protoplasmic antigen was highly sensitive as compared to commercial antigen in detecting Map infection therefore, could be used as 'Herd Screening Test' in buffaloes against Johne's disease. This pilot study first time reports a highly pathogenic 'Bison-type' genotype of M. avium subspecies paratuberculosis from the riverine buffaloes (Bubalus bubalis) of Agra region in North India.

Expression of a synthetic cry1EC gene for resistance against Spodoptera litura in transgenic peanut (Arachis hypogaea L.)

The tobacco cutworm (Spodoptera litura) is a polyphagous foliage insect and a major pest on peanut (Arachis hypogaea L.). S. litura is susceptible to the chimeric delta-endotoxin Cry1EC reported earlier. De-embryonated cotyledon explants of peanut were transformed using Agrobacterium tumefaciens strain EHA101 harboring a synthetic cry1EC gene driven by the CaMV 35S promoter. Transgenic plants of peanut with a single copy insertion of cry1EC were selected in the T(0) generation by Southern blot hybridization. Real-time PCR, Western blot and ELISA analysis indicated that expression of the cry1EC gene was higher in single copy T(1) plants. Immunoassay showed expression of Cry1EC up to 0.13% of total soluble protein in T(1) plants. Leaf feeding bioassay on highly expressing transgenic lines showed 100% killing of larvae at the 2(nd) instar stage of S. litura. This is the first report of transgenic peanut plants with resistance to S. litura.

Genetic analysis of resistance to Pyrenophora tritici-repentis races 1 and 5 in tetraploid and hexaploid wheat

Tan spot of wheat, caused by the fungus Pyrenophora tritici-repentis, is a destructive disease worldwide that can lead to serious losses in quality and quantity of wheat grain production. Resistance to multiple races of P. tritici-repentis was identified in a wide range of genetically diverse genotypes, including three different species Triticum aestivum (AABBDD), T. spelta (AABBDD), and T. turgidum (AABB). The major objectives of this study were to determine the genetic control of resistance to P. tritici-repentis races 1 and 5 in 12 newly identified sources of resistance. The parents, F(1), F(2), and F(2:3) or F(2:5) families of each cross were analyzed for the allelism tests and/or inheritance studies. Plants were inoculated at the two-leaf stage under controlled environmental conditions and disease reaction was assessed based on lesion-type rating scale. A single recessive gene controlled resistance to necrosis caused by P. tritici-repentis race 1 in both tetraploid and hexaploid resistant genotypes. The lack of segregation in the inter- and intra-specific crosses between the resistant tetraploid and hexaploid genotypes indicated that they possess the same genes for resistance to tan necrosis and chlorosis induced by P. tritici-repentis race 1. A single dominant gene for chlorosis in hexaploid wheat and a single recessive gene for necrosis in tetraploid wheat, controlled resistance to P. tritici-repentis race 5.

Immunology of mycobacterial infections: with special reference to Mycobacterium avium subspecies paratuberculosis

The interplay between mycobacteria and host determines the outcome of infection. After uptake of mycobacteria by macrophages, several possible scenarios may emerge; mycobacteria may be destroyed immediately or there is establishment of persistent infection. This review is focused around mycobacteria-host interactions with reference to Mycobacterium avium subspecies paratuberculosis (MAP) infection and highlights protective mechanisms involved in order to design vaccines and other control strategies.

Evaluation of indigenous milk ELISA with m-culture and m-PCR for the diagnosis of Bovine Johne’s disease (BJD) in lactating Indian dairy cattle

Present study is the first attempt to evaluate an indigenous milk ELISA with milk culture, standardize milk PCR, estimate lacto-prevalence of Map and genotype Map DNA from milk samples in few Indian dairy herds. In all 115 cows were sampled from 669 lactating cows in six dairy herds from three districts of North India. Fifty milk samples (four herds) were screened by three tests (milk culture, m-ELISA and m-PCR). Lacto-prevalence of Map in four dairy herds was 84.0% (50.0% in fat and 62.0% in sediment). Screening of both fat and sediment increased the sensitivity of culture. Colonies appeared between 45 and 120 DPI. In indigenous m-ELISA, protoplasmic antigen derived from native Map 'Bison type' strain of goat origin was used. Screening of 115 lactating cows by m-ELISA ('herd screening test') detected 32.1% positive lactating cows (lacto-prevalence). Sensitivity of ELISA was 28.5% and 42.8% in single point cutoff and S/P ratio, respectively. Lacto-prevalence of JD was high in dairy herds (66.6-100.0% by culture and 20.0-50.0% by m-ELISA). DDD farm, Mathura had very high (95.8%) and moderate prevalence of Map and lacto-antibodies, respectively. All cows were clinically suffering from JD. Specific IS 900 PCR was standardized in decontaminated fat and sediment of milk samples. DNA isolated from decontaminated pellets was amplified and characteristic 229 bp band was confirmatory for Map. Of the 50 milk samples, 6.0% were positive in m-PCR. The test needs further standardization. Map DNA were genotyped as Map 'Bison type' by IS 1311 PCR-REA. Of the three tests, milk culture was most sensitive followed by m-ELISA and m-PCR. Map DNA isolated from milk samples of dairy cattle were first time genotyped as Map, 'Bison type' in India. High prevalence of Map in milk of dairy herds, posed major health hazard for calves and human beings.

Genetic structure of Phaeosphaeria nodorum populations in the north-central and midwestern United States

Stagonospora nodorum blotch, caused by Phaeosphaeria nodorum, is considered one of the most destructive foliar diseases of wheat in the United States. However, relatively little is known about the population biology of this fungus in the major wheat-growing regions of the central United States. To rectify this situation, 308 single-spore isolates of P. nodorum were analyzed from 12 populations, five from hard red spring wheat cultivars in Minnesota and North Dakota and seven from soft red winter wheat in Indiana and Ohio. The genetic structure of the sampled populations was determined by analyzing polymorphisms at five microsatellite or simple-sequence repeat (SSR) loci and the mating type locus. Although a few clones were identified, most P. nodorum populations had high levels of gene (H(S) = 0.175 to 0.519) and genotype (D = 0.600 to 0.972) diversity. Gene diversity was higher among isolates collected from spring wheat cultivars in North Dakota and Minnesota (mean H(S) = 0.503) than in those from winter wheat cultivars in Indiana and Ohio (H(S) = 0.269). Analyses of clone-corrected data sets showed equal frequencies of both mating types in both regional and local populations, indicating that sexual recombination may occur regularly. However, significant gametic disequilibrium occurred in three of the four populations from North Dakota, and there was genetic differentiation both within and among locations. Genetic differentiation between the hard red spring and soft red winter wheat production regions was moderate (F(ST) = 0.168), but whether this is due to differences in wheat production or to geographical variation cannot be determined. These results suggest that sexual reproduction occurs in P. nodorum populations in the major wheat-growing regions of the central United States, and that geographically separated populations can be genetically differentiated, reflecting either restrictions on gene flow or selection.

Presence and characterization of Mycobacterium avium subspecies paratuberculosis from clinical and suspected cases of Crohn's disease and in the healthy human population in India

OBJECTIVES

To investigate and characterize Mycobacterium avium subspecies paratuberculosis (MAP) in patients with Crohn's disease, attendants of animals with suspected infection, and healthy humans, using multiple diagnostic tests.

METHODS

A total of 119 samples (35 stool, 76 serum, three blood clots, and five biopsies) were collected from five patients with Crohn's disease, eight attendants of animals with Johne's disease, and 93 apparently normal control subjects (Agra region) from North India. Samples were screened for the presence of MAP by smear examination, culture of stool, blood clot and biopsies, and ELISA. Colonies obtained by culture were further characterized using polymerase chain reaction (PCR) with IS900 MAP-specific primers.

RESULTS

Using all diagnostic modalities, MAP and/or MAP antibodies were identified in 100% (5/5) of subjects with Crohn's disease; 75.0% (6/8) of attendants of MAP infected animals were positive and 38.0% (27/71) of apparently normal controls were also positive. Most sensitive test was ELISA (100%, 5/5), followed by culture (80.0%, 4/5), and acid-fast staining. Ziehl-Neelsen staining was positive in 37.5% (3/8) of subjects with active animal husbandry practices. In 71 serum samples from control subjects, seroprevalence of MAP was 38.0% using indigenous protoplasmic antigens (PPA) and 36.6% using commercial PPA. Of the serum samples from the Crohn's disease patients, 100% (5/5) were positive by ELISA using indigenous PPA and 40.0% (2/5) were positive by ELISA using commercial PPA. IS900 PCR was used to characterize tiny colonies of MAP that grew extremely slowly on Herrold's egg yolk medium, and of 15 (42.8%) cultures, 14 (93.3%) were typed as MAP.

CONCLUSIONS

Paper documented the presence of MAP in all patients with Crohn's disease, in some animal attendants who had the history of working with goat herds infected with Johne's disease and in few normal healthy individuals. Presence of Ziehl Neelsen positive MAP. In the stool of attendants working with MAP-infected animals was unique to humans. ELISA based on antigens derived from indigenous MAP 'bison type' genotype of goat origin was most sensitive modality for screening Crohn's disease patients.

Reaction of Elite Wheat Genotypes from the Northern Great Plains of North America to Septoria Diseases

Stagonospora nodorum blotch (SNB), caused by Phaeosphaeria nodorum, and Septoria tritici blotch (STB), caused by Mycosphaerella graminicola, are the main pathogens of the Septoria disease complex of wheat (Triticum aestivum) in North America. This study was conducted to determine the disease reaction of 126 elite hard red spring, white, and durum wheat cultivars and advanced breeding lines collected from the northern Great Plains of the United States and Canada to SNB and STB. Seedlings of the 126 wheat genotypes were evaluated for resistance to SNB and STB under controlled environmental conditions. Moreover, these 126 wheat genotypes also were infiltrated with culture filtrate of P. nodorum isolate Sn2000. Based on disease reactions, three cultivars (McNeal, Dapps, and Oklee) and 12 advanced breeding lines (CA-901-580W, 97SO254-8-1, MN03291, MN03308, WA007925, MT0245, ND756, ND801, ND803, ND808, ND809, and ND811) adapted to the northern Great Plains were found to be resistant to both Septoria diseases and insensitive to the culture filtrate. Additionally, eight genetically diverse lines and cultivars, including two tetraploid wheat genotypes, were identified to be resistant to both Septoria diseases. These results suggest that the wheat genotypes contain a broad genetic base for resistance to the Septoria diseases in the northern Great Plains of the United States and Canada, and the resistant sources identified in this study may be utilized in wheat-breeding programs.

Mycobacterium avium subspecies paratuberculosis diagnosis and strain typing--present status and future developments

Mycobacterium avium subspecies paratuberculosis (MAP) is the etiological agent of paratuberculosis, a chronic gastroenteritis of ruminants and has zoonotic importance. We present here a review of MAP with respect to--(i) present diagnostic techniques and important developments; and (ii) MAP strain-typing tools. A summary of the findings to date is presented, and advantages and disadvantages of each of the methods are compared and discussed.

Non-chemical method of DNA recovery and characterization of Mycobacterium avium subspecies paratuberculosis using IS 900 PCR

In the present study, two methods of DNA isolation-routine, traditional and standard DNA isolation protocol for Mycobacteria (Method 1) and a new non-chemicals and non-enzymes (physical) method (Method 2) of DNA recovery have been compared and evaluated in IS900 PCR for the specific detection of pathogen. Using the new Method 2, DNA has been recovered from few (1 - 3 colonies), extremely minute and stunted colonies. DNA, thus, isolated from these colonies (colonies PCR) and cultured for the first time from the cases of Crohn's disease in human beings, dairy cattle, raw milk and pasteurized commercial milk samples has been characterized in the present study. It is the first report from India.

Comparative efficacy of an indigenous 'inactivated vaccine' using highly pathogenic field strain of Mycobacterium avium subspecies paratuberculosis 'Bison type' with a commercial vaccine for the control of Capri-paratuberculosis in India

Johne's disease (JD) is endemic in goatherds located at Central Institute for Research on Goats, Makhdoom, since 1979 and lately it has been reported from farmer's herds in equal frequencies. Despite using test and slaughter method for the control of JD for more than 25 years in these herds, incidence of JD has not been reduced. Efficacy of 'indigenous vaccine' containing native 'Bison type' genotype of Mycobacterium avium subspecies paratuberculosis (MAP) was compared with commercial vaccine using challenge studies with homologous strain of MAP. Goat kids (85) were randomly divided in to three groups. Kids were vaccinated with 1 ml of vaccine subcutaneously and Sham-immunized with 1 ml of sterile PBS. All kids except 3 in each group were challenged twice at 75- and 275-day post-vaccination (DPV). Four goats each from three groups were sacrificed at 200-day post-challenge to evaluate carcass and histopathologically for vaccine and challenge response in kids of different groups. Samples (blood, serum and fecal) were screened for LTT, ELISA and shedding of bacilli and data on live animal traits, mortality and experimental sacrifice were compared. Average body weights gained by goats in three groups at different stages of trials (0, 1-75, 76-275, 276-425 DPV) showed marked improvements in performance of vaccinated groups over 'Sham-immunized' group. Effect of vaccines against challenge became visible in terms of body weights gained at 276-425 DPV ('Bison' group gained significantly higher body weights than 'Sham-immunized'). Mortality was significantly less in two vaccinated as compared to 'Sham-immunized'. Vaccinated groups also had significant stimulation and sero-conversion for cell mediated and humoral immune response, respectively as compared to 'Sham-immunized'. Results of post-challenged fecal culture showed significant reduction in shedding of MAP in both vaccinated groups than in 'Sham-immunized'. There was significant improvement in external and internal body traits and histological lesions in case of vaccinated than 'Sham-immunized' group.

A comparative study on characterization of textile wastewaters (untreated and treated) toxicity by chemical and biological tests

Toxicity of textile wastewaters (untreated and treated) and their ingredient chemicals was quantified in terms of their chemical characteristics, fish (Gambusia affinis) mortality and end point growth responses of duckweed (Lemna aequinoctialis) in short-term bioassays. Other parameters of fish bioassay were erythrocyte morphology and its counts. Despite of a definite correlation between data of biological tests (LC/EC(50) values) with that of chemical tests, biological tests were found to be relatively more sensitive to both wastewaters and ingredient chemicals. Amongst all the examined parameters of test organisms, fish RBCs (morphology and counts) sensitivity to pollutants in the wastewaters was usually maximum and therefore, their study should be included in the routine fish bioassay. Other advantage of biological test such as on Lemna is even detection of eutrophic potential of wastewaters, as noted at their higher dilutions. The ingredient chemicals (major) contributing maximum toxicity to textile dye wastewater were, acids (HCl and H(2)SO(4)), alkali (Na(2)O SiO(2)), salt (NaNO(2)) and heavy metal (Cu), whereas dyes (4) were relatively less toxic.

Evaluation of highly sensitive indigenous milk ELISA kit with fecal culture, milk culture and fecal-PCR for the diagnosis of bovine Johne's disease (BJD) in India

Country lacks indigenous diagnostic kits against Johne's disease in animals. Indigenous ELISA and IS 900 PCR kits, originally developed for goats and sheep, have been adapted for screening of lactating cows. Multiple diagnostic tests were used to screen 26 lactating dairy cows against Johne's disease. Milk ELISA was evaluated with fecal culture, milk culture and fecal PCR. Of the 26 samples from lactating cows, 84.6, 96.1, 88.4 and 23.0% were positive in fecal culture, milk culture, m-ELISA and m-PCR, respectively. Comparatively milk sediment and milk fat culture detected 84.6 and 76.9% cows positive, respectively. Comparatively fecal culture and milk culture detected 84.6 and 96.1% cows positive, respectively. M-ELISA detected 11.5, 0.0, 11.5, 61.0 and 15.3%, cows as negative, suspected, low positive, positive and strong positive, respectively. There was good correlation between milk and fecal culture with m-ELISA. Three negative cows in m-ELISA were also detected in milk and fecal culture. Of the 26 decontaminated fecal samples, 23.0% cows were positive using specific IS 900 f-PCR. Comparative evaluation of m-ELISA with fecal and milk culture showed agreement in 80.7 and 84.6% cows, respectively. Sensitivity of m-ELISA with respect to fecal and culture was 90.9 and 95.6%, respectively. Comparative evaluation of four tests (milk culture, fecal culture, m-ELISA and f-PCR) showed that only 15.3% cows were detected in all the four tests. In three tests (fecal and milk culture and m-ELISA), 57.6% cows were detected positive. None of the cow was exclusively detected in f-PCR. Of the four diagnostic tests used milk culture was most sensitive (96.15%), followed by fecal culture (86.6%), m-ELISA (76.9%) and IS 900 PCR (23.0%) for the diagnosis of bovine Johne's disease (BJD). Milk ELISA detected only one cow extra, which was negative in milk culture. In view of the simplicity, rapidity and efficacy present milk ELISA kit employing soluble protoplasmic antigen from native Map 'Bison type' genotype of goat origin can be reliable for screening of bovine population against Johne's disease in India.

High Incidence of Tracheomalacia in Longstanding Goiters: Experience from an Endemic Goiter Region

BACKGROUND

Our institute caters to a large number of patients with large, longstanding multinodular goiters; tracheal deviation and resulting airway problems like tracheomalacia are relatively common. However, the literature is sparse on the criteria of early diagnosis and optimum management of tracheomalacia, which our study highlights.

METHODS

This retrospective study analyzed 900 thyroidectomies carried out during 1990-2005 for which data from 28 patients treated for tracheomalacia after thyroidectomy were available for analysis. Criteria for making a diagnosis of tracheomalacia after thyroidectomy included one or more of the following: normal vocal cord mobility, absence of glottic or subglottic edema or hematoma, soft and floppy trachea on palpation, obstruction to spontaneous respiration on gradual withdrawal of the endotracheal tube.

RESULTS

Mean duration of thyroid enlargement was 13.75 years. Only 7 patients had a history of stridor. Tracheostomy was performed in 26 patients, and 2 patients were put on prolonged intubation. Tracheostomy was performed in 18 patients on the operating table, and 8 in the recovery room. The mean weight of the gland was 442 g and histopathology revealed that 11 cases were benign goiter. The tracheostomy tube was removed after an average of 8.5 days. There were no cases of tracheal stenosis on long-term follow-up.

CONCLUSIONS

Patients with longstanding goiter, even when benign, are more prone to develop tracheomalacia. On the basis of our experience we strongly advocate tracheostomy intraoperatively if the trachea is soft and floppy and/or collapse of the trachea is observed following gradual withdrawal of the endotracheal tube.

Inflation with air via a facepiece for facilitating insertion of a nasogastric tube: a prospective, randomised, double-blind study

Insertion of a nasogastric tube is a routine procedure but during anaesthesia it is often difficult and time consuming. One hundred and sixty adults undergoing elective surgery under general anaesthesia were randomly divided into two groups. After induction of anaesthesia, neuromuscular blockade and tracheal intubation, a nasogastric tube was inserted through the nose with the head of the patient in the neutral position, either with or without prior inflation with air via a facepiece attached to a self-inflating bag applied firmly with the face. Insertion of the nasogastric tube was successful in 75/78 (96%) following inflation compared with 54/80 (68%) without inflation (p<0.001). In four patients receiving inflation, a fibreoptic endoscope was passed as far as the upper oesophageal sphincter; this revealed opening of the upper oesophageal sphincter during inflation.

Evaluation of Elite Wheat Germ Plasm for Resistance to Tan Spot

Tan spot, caused by Pyrenophora tritici-repentis, is a serious foliar disease of wheat (Triticum aestivum) in North America. Control of tan spot through management practices and fungicide application is possible; however, the use of resistant varieties is the most effective and economical means of controlling tan spot. This study was conducted to determine the disease reaction of 126 elite hard red spring, white, and durum wheat varieties and advanced breeding lines collected from the northern Great Plains of the United States and Canada to individual races/toxins of P. tritici-repentis. Seedling evaluation of the 126 genotypes was done under controlled environmental conditions with virulent races 2, 3, and 5 of P. tritici-repentis and toxins Ptr ToxA and Ptr ToxB. Based on disease reactions, two resistant varieties and two advanced breeding lines adapted to the northern Great Plains were found to be resistant to all the races and insensitive to the toxins tested. Additionally, six genetically diverse lines/varieties were identified to be resistant to tan spot; however, these sources may not be well adapted to the northern Great Plains. These results suggest that the wheat germ plasm contains a broad genetic base for resistance to the most prevalent races of P. tritici-repentis in North America, and the resistant sources identified in this study may be utilized in wheat breeding programs to develop tan spot resistant varieties.

Identification and Molecular Mapping of a Gene Conferring Resistance to Pyrenophora tritici-repentis Race 3 in Tetraploid Wheat

ABSTRACT Race 3 of the fungus Pyrenophora tritici-repentis, causal agent of tan spot, induces differential symptoms in tetraploid and hexaploid wheat, causing necrosis and chlorosis, respectively. This study was conducted to examine the genetic control of resistance to necrosis induced by P. tritici-repentis race 3 and to map resistance genes identified in tetraploid wheat (Triticum turgidum). A mapping population of recombinant inbred lines (RILs) was developed from a cross between the resistant genotype T. tur-gidum no. 283 (PI 352519) and the susceptible durum cv. Coulter. Based on the reactions of the Langdon-T. dicoccoides (LDN[DIC]) disomic substitution lines, chromosomal location of the resistance genes was determined and further molecular mapping of the resistance genes for race 3 was conducted in 80 RILs of the cross T. turgidum no. 283/Coulter. Plants were inoculated at the two-leaf stage and disease reaction was assessed 8 days after inoculation based on lesion type. Disease reaction of the LDN(DIC) lines and molecular mapping on the T. turgidum no. 283/Coulter population indicated that the gene, designated tsn2, conditioning resistance to race 3 is located on the long arm of chromosome 3B. Genetic analysis of the F(2) generation and of the F(4:5) and F(6:7) families indicated that a single recessive gene controlled resistance to necrosis induced by race 3 in the cross studied.

Ketamine for treatment of catheter related bladder discomfort: a prospective, randomized, placebo controlled and double blind study

BACKGROUND

Intraoperative urinary catheterization might cause postoperative catheter related bladder discomfort (CRBD). We evaluated the efficacy of ketamine as a treatment modality for CRBD.

METHODS

Fifty-four, ASA physical status I and II, male and female adult patients, having CRBD after elective percutaneous nephrolithotomy were randomized into two equal groups of 27 each. In the postoperative period, patients who complained of CRBD received medication depending upon group allocation. Group 1 (Control) received placebo, Group II (Ketamine) received i.v. ketamine 250 microg kg(-1). After induction of anaesthesia patients were catheterized with a 16 Fr Foley's catheter and the balloon was inflated with 10 ml distilled water. Grading of CRBD was done as none, mild, moderate and severe by a blinded observer at 0, 1, 2 and 6 h after operation.

RESULTS

Ketamine reduced the incidence of CRBD (P<0.001) at 2 and 6 h along with reduction in severity (P<0.05) at 1 h compared with control. Higher incidence of mild sedation was observed in the ketamine group (P<0.05) which was not associated with any untoward effects. Operative time and intraoperative fentanyl requirement were similar in both the groups.

CONCLUSION

I.V. ketamine (250 microg kg(-1)) is an effective treatment for reducing the incidence and severity of postoperative CRBD.

Prophylactic gabapentin for prevention of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy: a randomized, double-blind, placebo-controlled study

BACKGROUND

Gabapentin is an antiepileptic drug. Its antiemetic effect is demonstrated in chemotherapy-induced acute and delayed onset of nausea and vomiting in breast cancer patients.

AIM

To evaluate the antiemetic effect of gabapentin on incidence and severity of postoperative nausea and vomiting in laparoscopic cholecystectomy.

SETTINGS AND DESIGN

Double-blind, randomized, placebo-controlled study.

MATERIALS AND METHODS

Two hundred and fifty patients of ASA physical status I and II, scheduled for laparoscopic cholecystectomy were randomly assigned into two equal groups to receive 600 mg gabapentin or matching placebo two hours before surgery. Standard anaesthesia technique was used. Fentanyl was used as rescue postoperative analgesic. Ondansetron 4 mg was used intravenously as rescue medication for emesis. The total number of patients who had nausea or vomiting, and its severity and total fentanyl consumption in the first 24 hours were recorded.

STATISTICAL ANALYSIS

"Z test" was used to test the significance of severity of post-operative nausea and vomiting between groups. Fentanyl consumed in each group (Mean+/-SD) within 24 hrs was compared using student t test. P value < 0.05 was considered significant.

RESULTS

There were no demographic difference between the two groups. Incidence of post-operative nausea and vomiting within 24 hrs after laparoscopic cholecystectomy was significantly lower in gabapentin group (46/125) than in the placebo group (75/125) (37.8% vs 60%; P =0.04). There was a significantly decreased fentanyl consumption in gabapentin group (221.2+/-92.4 microg) as compared to placebo group (505.9+/-82.0 microg; P =0.01).

CONCLUSION

Gabapentin effectively suppresses nausea and vomiting in laparoscopic cholecystectomy and post-operative rescue analgesic requirement.

Evaluation of capsaicin ointment at the Korean hand acupressure point K-D2 for prevention of postoperative nausea and vomiting

The K-D2 point is the Korean hand acupressure point in Koryo Hand Therapy for prevention of postoperative nausea and vomiting. We evaluated the efficacy of capsaicin ointment at the K-D2 point in 186 patients undergoing laparoscopic cholecystectomy in a randomised, prospective, double-blind and placebo-controlled study. Patients were randomised to have either placebo ointment or capsaicin ointment applied to the K-D2 point of both hands 1 h before surgery under standardised anaesthesia. The ointment was removed 8 h later. Postoperative nausea and vomiting was evaluated 6 and 24 h following surgery. The incidence of postoperative nausea and vomiting was lower in the capsaicin group, with an absolute risk reduction (ARR) of 21%, a relative risk reduction (RRR) of 50% and a number-needed-to-treat (NNT) of 5 at 0-6 h (p = 0.001), and an ARR of 11%, a RRR of 85% and a NNT of 9 at 6-24 h (p = 0.003). The need for rescue anti-emetic treatment was also lower at 0-6 h (3 (3%) vs 11 (12%); p = 0.04) and at 6-24 h (5 (5%) vs 0; p = 0.02).

Short-term effect of complementary feeding frequency on total ad libitum consumption in 6- to 10-month-old breast fed Indian infants

OBJECTIVE

To evaluate the short-term effect of frequency of complementary feeding on total ad libitum consumption in breast fed infants.

METHODS

Twenty infants between 6 to 10 months of age were studied in a tertiary hospital in New Delhi for 48 hours. A traditional gruel made of rice and pulses (mean (SD) caloric density 54.22 (7.08) kcal/100 g) was offered in a randomized manner three (n = 10) or four (n = 10) times per day to the subjects over the first 24 hours with the subjects crossing over in the next 24 hours. They were allowed ad libitum breast feeding with no other food or fluid during the study period. Total caloric intake from breast milk and semisolids was computed for each day.

RESULTS

There was no difference in the total caloric consumption with a semisolid feeding frequency of three or four times per day. The frequency of breast feeding and the breast feeding duration were also comparable (P > 0.05). However, breast milk intake was lower with a semisolid feeding frequency of 4 times/day (mean difference -61.2 g/d [95% confidence interval (CI) -122.2-0.32]; P = 0.051). The time required for feeding was higher (mean difference 14.75 min; P < 0.001), whereas the per meal intake of semisolids was lower with four semisolid feeds per day (mean difference -5.5 kcal/meal; [95% CI -10.19 to -0.81]; P = 0.024).

CONCLUSION

In the short term, a change in semisolid feeding frequency from three to four times per day does not result in enhanced energy consumption because of lower breast milk intake.

Morphological, physiochemical and molecular characterization of Anabaena strains

A set of 30 Anabaena strains, isolated from diverse geographical regions of India, were characterized using morphological and physiochemical attributes as well as molecular marker profiles. Significant differences were observed among the Anabaena strains with regard to the shape and size of trichomes and individual cells within a filament, besides qualitative and quantitative aspects of phycobiliprotein accumulation and activities of enzymes involved in nitrogen metabolism. Analyses of molecular polymorphisms in a selected set of 13 Anabaena strains, using primers based on repetitive sequences in the genome, led to unambiguous differentiation of the strains as well as understanding of their genetic relationships. Informative morphological, physio-chemical and molecular characters have been identified that could aid in differentiation and utilization of Anabaena strains as bioinoculants or as sources of pigments.

Clinical evaluation of the ‘T-Dagger™’: a new bedside percutaneous dilational tracheostomy device

A number of percutaneous dilational tracheostomy devices are now available for clinical use. Recently, a new percutaneous dilational tracheostomy device, the "T-Dagger" (Criticure Invasives, India), has been introduced for rapid bedside percutaneous tracheostomy. In a prospective preliminary study, we have performed percutaneous dilational tracheostomy (PDT) using the T-Dagger in 20 adult ventilated patients in order to evaluate the safety and efficacy of the new device. The T-Dagger facilitated bedside PDT in about 3 min with no untoward incidents. There was no significant bleeding, pneumothorax, pneumomediastinum, tracheal wall injuries or difficulty in ventilation in any of the patients. We conclude that the T-Dagger shows early promise in bedside percutaneous dilational tracheostomy. However, controlled studies are required in a larger patient population before it can be recommended for routine use.

Short-term effect of oil supplementation of complementary food on total ad libitum consumption in 6- to 10-month-old breastfed Indian infants

OBJECTIVES

To evaluate the short term effect of oil supplementation of complementary food on total ad libitum consumption in breastfed infants.

METHODS

Twenty infants between 6 to 10 months of age were studied in a tertiary hospital in New Delhi for 48 hours. They were given three semi-solid complementary feeds per day and ad libitum breastfeeding. No other food or fluid was allowed during the study period. A traditional gruel made of rice and pulses with high energy density (oil added; caloric density = 35 kcal/100 g) or low energy density (without oil; caloric density = 20 kcal/100 g) was offered in a randomized manner on consecutive days to all infants. Total caloric intake from breast milk and semi-solids was computed for each day.

RESULTS

Infants consumed an equivalent amount of semi-solid (mean difference, 10.75 g/day; 95% confidence interval, 10.56 to 32.06; P = 0.304) and a lower amount of breast milk (mean difference, 121.1 g/day; 95% confidence interval, 35.13 to 207.16; P = 0.008) when high energy density feeds were offered. Although the caloric intake from semi-solids increased significantly (18.9 kcal/day; 95% confidence interval, 12.9 to 24.8; P < 0.001) with the high density diet, the total caloric intake (breast milk and study feeds) decreased (mean difference = 59.6 kcal/day; 95% confidence interval, 5.95 to 113.34; P = 0.031). An inverse relationship was found between caloric density of semi-solids and breast milk intake (r = 0.34, r = 0.12, P = 0.032).

CONCLUSION

In the short term, oil supplementation of complementary food in breastfed infants does not translate into enhanced total caloric intake, primarily as a result of breast milk displacement.

Exchangeable sodium induced changes in yield, water relation and cation composition of fennel (Foeniculum vulgare Mill)

A pot experiment was conducted with the objectives to assess the adaptation potential of fennel crop grown at 10, 20, 25, 35 and 40 ESP (exchangeable sodium percentage) levels. Results showed that the rate of seed germination, plant growth including branching pattern, umbels per plant and 1000 test seed weight were adversely affected by sodic soils. Assuming that fifty percent reduction in seed yield and Na+/K+ ratio in leaf tissue as an index of alkali tolerance revealed that fennel was tolerant up to 25 ESP. The cell sap pH and EC reflected optimum osmoticum maintenance to withstand sodicity stress at this level and beyond this leaf water potential decreased (negatively) more to impede water uptake.

Fungicidal elements accumulated in Cryptothecia punctulata (Ascomycetes lichen) of an arecanut orchard in South India

Different nutrient elements were analyzed in the lichen Cryptothecia punctulata collected from the arecanut trees which were exposed to several sprays of a fungicide Bordeaux mixture. The study revealed the accumulation of fungicidal elements such as Cu, Ca and S in higher concentration of 575.4, 10,000 and 21,000 microg g(-1), respectively.

Genetic Control of Resistance to Tan Necrosis Induced by Pyrenophora tritici-repentis, Races 1 and 2, in Spring and Winter Wheat Genotypes

ABSTRACT The symptoms of tan spot of wheat, caused by Pyrenophora triticirepentis, include a tan necrosis component and an extensive chlorosis component. Since tan spot has become the major component of the leafspotting disease complex of wheat in western Canada, the need for resistant cultivars has increased. This study was conducted to determine whether the resistance to tan spot found in a diverse set of spring and winter wheat genotypes was due to resistance genes not previously reported. The genetic control of resistance to necrosis induced by P. triticirepentis race 1 and race 2 was determined, under controlled environmental conditions, for spring wheat genotypes Erik and 86ISMN 2137 and winter wheat genotypes Hadden, Red Chief, and 6B-365. Plants were inoculated at the two-leaf stage and disease reaction was assessed based on lesion type. Tests of the F(1) and F(2) generations, and of F(2:3) and F(2:8) families, indicated that one recessive gene controlled resistance to the necrosis component of tan spot caused by both race 1 and race 2 in each cross studied. Lack of segregation in crosses between the resistant cultivars indicated that the resistance gene was the same in all of the cultivars.

Effect of spironolactone on acid and alkaline phosphatase in the testes of albino rat

The biological activity of the mineralocorticoid antagonist, spironolactone depend upon its metabolism. In this study the effect of diuretic drug compound spironolactone on the acid and alkaline phosphatase in the testes of albino rat. The drug spironolactone was administered orally daily for 7(th), 14(th) and 21(st) days at the dose of 100 mg/kg body weight. Among them, the side effects of drug are that the degradation of alkaline phosphatase in the testes; while acid phosphatase increased significantly may be due to 7a-thiospironolactone is a tissue metabolite of spironolactone and may contribute to the testicular enzymes, therapeutic actions and some other side effects. It is suggested that the decrease and increase of alkaline and acid phosphatase in the testes of albino rat are the due to the side effects of spironolactone drug compound.

Increased epithelial uptake of protein antigens in the ileum of Crohn's disease mediated by tumour necrosis factor alpha

BACKGROUND AND AIMS

The exact nature of the epithelial barrier defect in Crohn's disease remains to be elucidated. Previously we showed increased permeability to proteins in ileal Crohn's disease. Our aims were to study if this barrier defect (a) involves endocytotic uptake of antigens and (b) is related to low grade inflammation not detectable by histology.

METHODS

Macroscopically normal segments of distal ileum of Crohn's disease patients (n = 10) were subgrouped into non-inflamed (histologically unaffected) and slightly inflamed tissues and studied in Ussing chambers, with normal ileal specimens from colon cancer patients (n = 9) as controls. Endocytotic uptake into enterocytes of the protein antigen horseradish peroxidase was assessed by measuring the area of horseradish peroxidase containing endosomes in electron photomicrographs. Mucosal tumour necrosis factor alpha (TNF-alpha) mRNA was quantified using real time polymerase chain reaction. For comparison, the effects of low doses of TNF-alpha on endosomal uptake of horseradish peroxidase were studied in cultured T84 cells grown on filter supports.

RESULTS

The area of horseradish peroxidase containing endosomes was increased (p<0.001) in enterocytes of non-inflamed ileum of Crohn's disease (2.8 (0.7) mum(2)/300 mum(2)) compared with control ileum (0.6 (0.06)). In non-inflamed mucosa, a significant association between endosomal uptake and mucosal expression of TNF-alpha mRNA (p = 0.03) was found. Low concentrations of TNF-alpha (0.25-1.0 ng/ml) enhanced the endosomal uptake of horseradish peroxidase in polarised T84 cells, without affecting transepithelial electrical resistance.

CONCLUSIONS

Our findings suggest increased endosomal uptake of antigens in ileal Crohn's disease that may be mediated by TNF-alpha. These data highlight the transcellular route of antigen uptake in barrier dysfunction and implicate the interaction between epithelial cells and the innate immune system in the development of mucosal inflammation.

Development of a hybrid delta-endotoxin and its expression in tobacco and cotton for control of a polyphagous pest Spodoptera litura

A hybrid delta-endotoxin protein was designed against a polyphagous lepidopteran insect pest Spodoptera litura, which is tolerant to most of the known delta-endotoxins. The hybrid delta-endotoxin was created by replacing amino acid residues 530-587 in a poorly active natural Cry1Ea protein, with a highly homologous 70 amino acid region of Cry1Ca in domain III. The truncated delta-endotoxins Cry1Ea, Cry1Ca and the hybrid protein Cry1EC accumulated in Escherichia coli to form inclusion bodies. The solubilised Cry1EC made from E. coli was 4- fold more toxic to the larvae of S. litura than Cry1Ca, the best known delta-endotoxin against Spodoptera sp. None of the two truncated toxins, solubilised from E. coli caused larval mortality. However, trypsinised Cry1Ca protoxin obtained from E. coli and solubilised from inclusion bodies caused mortality of S. litura with LC50 513 ng/ml semi synthetic diet. A synthetic gene coding for the hybrid delta-endotoxin Cry1EC was designed for high level expression in plants, taking into consideration several features found in the highly expressed plant genes. Transgenic, single copy plants of tobacco as well as cotton were developed. The selected lines expressed Cry1EC at 0.1-0.7% of soluble leaf protein. Such plants were completely resistant to S. litura and caused 100% mortality in all stages of larval development. Hence, unlike in E. coli, the hybrid delta-endotoxin folded into a functionally active conformation in both tobacco and cotton leaves. The truncated Cry1EC expressed in tobacco leaves was about 8-fold more toxic (LC50 58 ng/ml diet) compared to expression in E. coli.

Effect of glucose and light-dark environment on pigmentation profiles in the cyanobacterium Calothrix elenkenii

Calothrix elenkenii was evaluated for accumulation of chlorophyll, beta-carotene and phycobiliproteins when grown under light-dark cycles and darkness, in the presence of glucose. Highest values of beta-carotene, chlorophyll, proteins and acetylene-reducing activity were recorded when the organism was grown in the presence of glucose under light-dark cycles after 15 d of incubation. The presence of glucose in the medium stimulated pigment production, especially of beta-carotene and chlorophyll, which may be due to increased energy-linked assimilation and ATP production. The photoheterotrophic potential of C. elenkenii can be exploited in value addition for increased and economic production of pigments.

Assessment of right ventricular diastolic function: does it predict post-operative course in tetralogy of Fallot

BACKGROUND

In some cases of tetralogy of Fallot the post-operative course is characterized by episodes of low cardiac output, elevated central filling pressures and prolonged ventilation and inotropic support. This may be due to impaired diastolic function of the right ventricle despite preservation of biventricular systolic function.

METHODS AND RESULTS

Sixty-four consecutive patients (mean age 7.06+/-4.9 years) undergoing repair of tetralogy of Fallot were prospectively studied to assess right ventricular diastolic function. 'Restrictive physiology' was defined as presence of laminar antegrade diastolic pulmonary artery flow (A wave) throughout the respiratory cycle, which was coincident with atrial systole. Right ventricle restriction was present in 45/64 (70%, Group 1) patients and absent in 19/64 (30%, Group 2) patients. There was a marked inspiratory augmentation of the pulmonary artery A wave velocity, flow integral and duration. Transtricuspid flow revealed significantly lower peak E velocity, lower E/A ratio, shorter E deceleration time and higher A velocity time integral in those with right ventricular restriction. Biventricular systolic function and transmitral flow were normal in all patients. Those with restrictive physiology had significantly longer mean inotrope support duration, longer ventilation and chest drainage times. Correspondingly, the mean intensive care unit stay (56.7+/-9.3 v. 34.7+/-5.38 hours, p<0.01) and mean hospital discharge time (9.3+/-2.3 v. 6.2+/-0.5 days, p <0.001) was also significantly longer in group 1.

CONCLUSIONS

Right ventricular restriction (as seen by laminar antegrade diastolic pulmonary artery flow throughout the respiratory cycle) exists in a significant subset of patients with tetralogy of Fallot following operative repair. Following surgery, such patients have higher inotropic requirement, longer ventilation times and longer hospital stay.

Genetic resistance of Barbari and Jamunapari kids to natural infection with gastrointestinal nematodes

An investigation was made in 252 Barbari and Jamunapari kids to assess their resistance to natural infection with gastrointestinal (GI) nematodes and to establish indicator traits for such resistance in Indian goats. The indicator traits, faecal egg counts (FEC) and packed cell volume (PCV) were affected by various genetic and non-genetic factors. There were no breed differences in the FEC or PCV at 3, 6 or 9 months of age. Jamunapari male kids had a higher FEC than the female kids at 6 months of age. However, Barbari female kids had a higher FEC than the respective male kids at 9 months of age. At 6 months of age in both breeds, the kids born in the spring (March-April) had a higher FEC than those born in the autumn (October-November). The FEC of kids at 9 months of age was higher than at 3 or 6 months of age. Sire had a significant effect on PCV at 6 and 9 months of age. The kids born in the autumn had a higher PCV than those born in the spring. The PCV of male Barbari kids differed significantly from that of female kids at all the ages. The correlation coefficient of FEC on both body weight and body weight gain was negative, and there was a loss of body weight in the individuals with a high FEC.

Isolation and characterization of an indigenous isolate of Dunaliella sp. for beta-carotene and glycerol production from a hypersaline lake in India

Dunaliella, a green alga grows in a wide range of marine and freshwater habitats such as oceans, brine lakes, salt marshes and salt-water ditches near the sea, predominantly in water bodies containing more than 10% salt. Sambhar salt lake, Rajasthan (India) was found as one of the natural habitat of Dunaliella sp. The species was isolated and screened for accumulation of beta-carotene and glycerol. It was studied for the growth attributes like total protein, optical density, total chlorophyll, total carotenoid, beta-carotene and glycerol. Under unstressed physico-chemical conditions the maximum beta-carotene and glycerol observed was 1.15 pg/cell and 94.26 pg/cell respectively. The stress (salt stress (NaCl), high light intensities and continuous light) allowed the alga to accumulate high beta-carotene (approximately 4.21 pg/cell under 118.18 micromole m(-2) s(-1) of light intensity) without massive reduction in biomass content. This opens up new avenues for exploring this strain for future research and its commercial exploitation.

Isolation and characterisation of phycobiliprotein rich mutant of cyanobacterium Synechocystis sp

Chemical (N' methyl-N'-nitro-N-nitrosoguanidine) mutagenesis and penicillin selection were utilised to isolate a phenotypically altered mutant of cyanobacterium Synechocystis sp. This mutant (ntm60A) exhibited enhanced protein content and nitrogen fixing potential but lower amount of chlorophyll and nitrate reductase activity. A remarkable and significant increase was observed in the total phycobiliprotein content of the mutant, especially in relation to the amount of phycoerythrin. This strain can be exploited as a rich source of natural coloring agent such as phycobilins in the bioindustry.

Effect of nutrient depletion on beta-carotene and glycerol accumulation in two strains of Dunaliella sp

The response of two strains of Dunaliella, a beta-carotene accumulating halotolerant alga, was evaluated under sulphate, nitrate and phosphate limitation. All these factors decreased the growth rate and chlorophyll content but, increased the beta-carotene content of the two isolates of Dunaliella, D1, obtained from GTCC and D2 an indigenous strain isolated from Sambhar salt lake, India. Both the strains exhibited accumulation of beta-carotene and glycerol under the different nutrient limiting conditions. A maximum accumulation of 3.99 pg/cell of beta-carotene was observed under phosphate depletion. However, nutrient depletion did not significantly affect the glycerol accumulation in these cells. D2, the indigenous isolate, was found to be a better accumulator of beta-carotene than D1.

Evaluation of Tolypothrix germplasm for phycobiliprotein content

Twenty Tolypothrix strains, including 15 strains of T. tenuis, three strains of T. ceylonica and one strain each of T. nodosa and T. bouteillei, were evaluated for their phycobiliprotein content and composition. Significant differences among the Tolypothrix strains were found at both inter- and intra-specific levels in the production of phycobiliprotein constituents--phycocyanin (PC), allophycocyanin (APC) and phycoerythrin (PE). Four specific parameters, viz. PC or PE content, total phycobiliprotein and total protein content, and percentage of phycobiliproteins, in a mixture of total proteins were used to select four T. tenuis and one T. ceylonica strain as useful for phycobiliproteins production.

Effect of thiazide drug compound on the testicular protein and cholesterol contents of albino rat

In this study the effect of thiazide diuretic compound on the protein and cholesterol contents in the testes of albino rats as the experimental model. The drug thiazide was administered orally daily for 10,20 and 30 days at the dose of 100mg/kg body weight. Total protein decrease in the testes of rats were evidenced may be due to the side effects of thiazide drug compound which is linked with the hyponatremia and protein metabolism. An elevated level of cholesterol contents observed in thiazide treated rats also revealed that the side effect of drug compound thiazide and also may be due to the stimulation of catecholamine which is stimulated therefore, the biochemical estimation such as protein and cholesterol in the testes after the thiazide treatment determined the effectiveness of diuretic drug compound would provide clinical evidences of their side effects.

Cadmium toxicity induced changes in plant water relations and oxidative metabolism of Brassica juncea L. plants

Excess of cadmium (Cd) induced changes in oxidative scenario and water status of plants viz.., total water content, specific water content, water saturation deficit (WSD) and transpiration of Brassica juncea plants grown in soil pot culture. Although lower and marginal levels of excess cadmium (100 and 250 ppm) improved growth but higher levels (500 ppm) caused significant suppression. Significant accumulation of proline, an indicator of water stress, occurred at higher level of Cd. Gradual increases in activities of certain antioxidant enzymes such as catalase and peroxidase along with increased lipid peroxidation are suggestive of disturbed oxidative metabolism. Taking together, the deleterious effects of Cd and its effects on oxidative metabolism clearly indicate enhanced generation of reactive oxygen species (ROS) to be instrumental in producing toxic effects of Cd. The excess levels of Cd also decreased the concentrations of soluble protein and chlorophylls and increased the ratio of chlorophyll a/b.

Methane production in rice soil is inhibited by cyanobacteria

The present study was aimed at understanding the role of cyanobacteria and Azolla in methane production and oxidation in laboratory simulation experiments using soil samples from rice fields. All the seven cyanobacterial strains tested effected a significant decrease in the headspace concentration of methane in flooded soil, incubated under light. Synechocystis sp. was the most effective in retarding methane concentration by 10-20 fold over that in controls without cyanobacteria. The decrease in the headspace concentration of methane was negligible in nonsterile soil samples, inoculated with Synechocystis sp. and then incubated under dark. Moist soil cores (0-5 cm depth), collected from rice fields that had been treated with urea in combination with a cyanobacterial mixture, Azolla microphylla, or cyanobacterial mixture plus A. microphylla, effected distinctly more rapid decrease in the headspace concentration of methane added at 200 microl(-1) than did the soil cores from plots treated with urea alone (30, 60, 90 and 120 kg N ha(-1)), irrespective of the rate of chemical nitrogen applied to rice fields. Besides, soil cores from plots treated with urea alone at 60, 90 and 120 kg N ha(-1) oxidised methane more rapidly than did the core samples from plots treated with urea alone at 30kg N ha(-1). Cyanobacteria and A. microphylla, applied to flood water, appear to play a major role in mitigation of methane emission from rice fields-through enhanced methane oxidation.