Acoustomechanically activatable liposomes for ultrasonic drug uncaging

Ultrasound-activatable drug-loaded nanocarriers enable noninvasive and spatiotemporally-precise on-demand drug delivery throughout the body. However, most systems for ultrasonic drug uncaging utilize cavitation or heating as the drug release mechanism and often incorporate relatively exotic excipients into the formulation that together limit the drug-loading potential, stability, and clinical translatability and applicability of these systems. Here we describe an alternate strategy for the design of such systems in which the acoustic impedance and osmolarity of the internal liquid phase of a drug-loaded particle is tuned to maximize ultrasound-induced drug release. No gas phase, cavitation, or medium heating is necessary for the drug release mechanism. Instead, a non-cavitation-based mechanical response to ultrasound mediates the drug release. Importantly, this strategy can be implemented with relatively common pharmaceutical excipients, as we demonstrate here by implementing this mechanism with the inclusion of a few percent sucrose into the internal buffer of a liposome. Further, the ultrasound protocols sufficient for in vivo drug uncaging with this system are achievable with current clinical therapeutic ultrasound systems and with intensities that are within FDA and society guidelines for safe transcranial ultrasound application. Finally, this current implementation of this mechanism should be versatile and effective for the loading and uncaging of any therapeutic that may be loaded into a liposome, as we demonstrate for four different drugs in vitro, and two in vivo. These acoustomechanically activatable liposomes formulated with common pharmaceutical excipients promise a system with high clinical translational potential for ultrasonic drug uncaging of myriad drugs of clinical interest.

Dose-Dependent Dissociation of Pro-cognitive Effects of Donepezil on Attention and Cognitive Flexibility in Rhesus Monkeys

Background

Donepezil exerts pro-cognitive effects by nonselectively enhancing acetylcholine (ACh) across multiple brain systems. Two brain systems that mediate pro-cognitive effects of attentional control and cognitive flexibility are the prefrontal cortex and the anterior striatum, which have different pharmacokinetic sensitivities to ACh modulation. We speculated that these area-specific ACh profiles lead to distinct optimal dose ranges for donepezil to enhance the cognitive domains of attention and flexible learning.

Methods

To test for dose-specific effects of donepezil on different cognitive domains, we devised a multitask paradigm for nonhuman primates that assessed attention and cognitive flexibility. The nonhuman primates received either vehicle or variable doses of donepezil before task performance. We measured intracerebral donepezil and its strength in preventing the breakdown of ACh within the prefrontal cortex and anterior striatum using solid phase microextraction neurochemistry.

Results

The highest administered donepezil dose improved attention and made the subjects more robust against distractor interference, but it did not improve flexible learning. In contrast, only a lower dose range of donepezil improved flexible learning and reduced perseveration, but without distractor-dependent attentional improvement. Neurochemical measurements confirmed a dose-dependent increase of extracellular donepezil and decreases in choline within the prefrontal cortex and the striatum.

Conclusions

The donepezil dose for maximally improving attention differed from the dose range that enhanced cognitive flexibility despite the availability of the drug in two major brain systems supporting these functions. These results suggest that in our cohort of adult monkeys, donepezil traded improvements in attention for improvements in cognitive flexibility at a given dose range.

Optimizing a High-Throughput Solid-Phase Microextraction System to Determine the Plasma Protein Binding of Drugs in Human Plasma

Plasma protein binding refers to the binding of a drug to plasma proteins after entering the body. The measurement of plasma protein binding is essential during drug development and in clinical practice, as it provides a more detailed understanding of the available free concentration of a drug in the blood, which is in turn critical for pharmacokinetics and pharmacodynamics studies. In addition, the accurate determination of the free concentration of a drug in the blood is also highly important for therapeutic drug monitoring and in personalized medicine. The present study uses C₁₈-coated solid-phase microextraction 96-pin devices to determine the free concentrations of a set of drugs in plasma, as well as the plasma protein binding of drugs with a wide range of physicochemical properties. It should be noted that the extracted amounts used to calculate the binding constants and plasma protein bindings should be measured at respective equilibrium for plasma and phosphate buffer. Therefore, special attention is placed on properly determining the equilibration times required to correctly estimate the free concentrations of drugs in the investigated systems. The plasma protein binding values obtained with the 96-pin devices are consistent with those reported in the literature. The 96-pin device used in this research can be easily coupled with a Concept96 or other automated robotic systems to create an automated plasma protein binding determination protocol that is both more time and labor efficient compared to conventional equilibrium dialysis and ultrafiltration methods.

Gas chromatography-mass spectrometric identification of cyanide using a nucleophilic substitution based derivatization with S-phenyl benzenethiosulfonate

A novel, simple and efficient analytical method for GC-MS based identification of cyanide has been developed using a single step nucleophilic substitution based derivatization of cyanide in aqueous medium. The nucleophilic substitution reaction of cyanide with S-phenyl benzenethiosulfonate results in the formation of phenyl thiocyanate as a cyanide derivative and it was found that the relative response of the resultant cyanide derivative was much higher than that of the cyanide derivatives resulting from disulfide based derivatizing agents. The sample preparation protocol for the identification of cyanide in aqueous samples was also optimized with the new derivatizing agent. Derivatization followed by liquid-liquid extraction was employed for the preparation of aqueous samples containing cyanide salts. The resultant samples were subjected to GC-MS analysis for the identification of the cyanide derivative. Under optimized conditions, the detection and quantification limits for cyanide aqueous samples were found to be 0.075 μg mL-1 and 0.25 μg mL-1 respectively. The calibration curve had a linear relationship with y = 0.086x - 0.076 and r2 = 0.997 for the working range of 0.25 μg mL-1 to 50 μg mL-1. The intraday RSDs were between 2.24 and 8.17%, and the interday RSDs were between 2.22 and 12.85%. The method can also be successfully employed for the identification of hydrogen cyanide in aqueous medium. The applicability of the present method was demonstrated by analysing a real sample from apple seed extraction.

Gas chromatography-tandem mass spectrometry-based detection of half nitrogen mustards in plasma as a new biomarker of nitrogen mustard exposure

The development and optimization of an analytical method for the detection and identification of reactive metabolite of organochlorine chemical warfare agent nitrogen mustards (NMs), 2-[(2-chloroethyl)(alkyl)amino]ethanol (CEAAE), known as half nitrogen mustard, in blood samples is presented, herein. In this study, half nitrogen mustards in plasma are presented as a new and unambiguous biomarker of NM exposure since the fully hydrolyzed product, i.e., amino alcohols, are common industrial chemicals that can be present as such without getting exposed to NMs. Thus, the detection of half nitrogen mustard as a biomarker holds great significance for verification by the Chemical Weapon Convention (CWC) and will also be helpful in understanding the pharmacokinetics of NM-based chemotherapeutic pro-drugs. To the best of our knowledge, this is the first report on the detection of half nitrogen mustards in any matrice, including plasma. A very simple sample preparation protocol was developed for its extraction from plasma samples. Heptafluorobutyrylation and gas chromatography-tandem mass spectrometry in the positive chemical ionization mode were developed for the detection and identification of halfNMs. The developed method has shown excellent analytical figures of merits such as a wide range of linearity (1.0-50 ng mL^-1), low limit of detection (0.3-0.5 ng mL^-1), and low limit of quantification (1.0 ng mL^-1). The interday and intraday reproducibilities were also less than 15%. The developed method was successfully applied to real-world samples; in vitro human plasma was spiked with ∼1 ng mL^-1 of all the NMs and in vivo studies were done with rats intravenously exposed to 1 × LD₅₀ of bis(2-chloroethyl)methylamine (HN2).

Mass spectral fragmentation of perfluoroacyl derivatives of half nitrogen mustards for their detection by gas chromatography/mass spectrometry

RATIONALE

Analytical methods for the detection and identification of half nitrogen mustards (halfNMs), i.e., partially hydrolyzed products of nitrogen mustards (pHpNMs), using silyl derivatives are often associated with low sensitivity and selectivity. In order to overcome these limitations, the derivatization of halfNMs was performed using perfluoroacylation.

METHODS

Two efficient derivatization techniques using trifluoroacetyl (TFA) and heptafluorobutyryl (HFB) groups were developed for the unambiguous identification of halfNMs. A mass spectral database was generated by performing gas chromatography/electron ionization mass spectrometry (GC/EI-MS) and gas chromatography/positive chemical ionization mass spectrometry (GC/PCI-MS). The fragmentation pathways were studied by tandem mass spectrometry (MS/MS) in both EI and PCI mode.

RESULTS

The EI-MS spectra of the TFA and HFB derivatives of halfNMs contain intense molecular ions and fragment ions, thus making perfluoroacylation preferable to silylation. In addition, the background-free chromatogram obtained using these derivatives provides unambiguous identification of these compounds in blind samples. The structures of the fragment ions were postulated, and the sources of significant ions were traced by performing MS/MS precursor ion scans. In the PCI-MS spectra, along with the protonated molecule, significant peaks due to neutral losses of HF, HCl, CH₃ Cl and CF₃ COOH were observed.

CONCLUSIONS

This is the first report of the elucidation of the fragmentation pathways of perfluoroacyl derivatives of halfNMs. The complementary GC/PCI-MS and GC/PCI-MS/MS data will be helpful in the identification of unknown metabolites in a fast and reliable fashion.

Mass spectral studies of silyl derivatives of partially hydrolyzed products of nitrogen mustards: Important markers of nitrogen mustard exposure

RATIONALE

Nitrogen mustards (NMs) are vesicant class of chemical warfare agents. From the viewpoint of the Chemical Weapons Convention partially hydrolyzed products of nitrogen mustards (pHpNMs) are considered as important markers of nitrogen mustard exposure. The detection of pHpNMs from biological or environmental samples is highly useful for obtaining forensic evidence of exposure to NMs.

METHODS

Gas chromatography interfaced with tandem mass spectrometry (GC/MS/MS) is a widely used tool for the identification and sensitive detection of metabolites of NMs in complex matrices. The pHpNMs were derivatized using silylating agents as they are highly polar and non-amenable to GC. The mass spectral studies of these silyl derivatives of pHpNMs were performed using GC/MS/MS in both electron ionization (EI) and chemical ionization (CI) mode.

RESULTS

Various approaches have been proposed to assess the fragmentation pathways of the trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS) derivatives of pHpNMs. All the proposed fragmentation pathways were based on the product and/or precursor ion scanning of corresponding ions in both EI and CI mode. In the case of EI, most of the fragmentation pathways involved either α-cleavage or inductive cleavage.

CONCLUSIONS

This is the first report on the MS study of the silyl derivatives of pHpNMs. The study of the two different derivatives of pHpNMs using both EI- and CI-MS provides a reliable, unambiguous identification of pHpNMs in complex environmental and biomedical matrices (such as plasma and urine) during any verification activities.

Triazine-Based Covalent Organic Framework: A Promising Sorbent for Efficient Elimination of the Hydrocarbon Backgrounds of Organic Sample for GC-MS and 1H NMR Analysis of Chemical Weapons Convention Related Compounds

The strict monitoring and precise measurements of chemical warfare agents (CWAs) in environmental and other complex samples with high accuracy have great practical significance from the forensic and Chemical Weapons Convention (CWC) verification point of view. Therefore, this study was aimed to develop an efficient extraction and enrichment method for identification and quantification of toxic agents, especially with high sensitivity and multidetection ability in complex samples. It is the first study on solid-phase extraction (SPE) of CWAs and their related compounds from hydrocarbon backgrounds using covalent triazine-based frameworks (CTFs). This nitrogen-rich CTF sorbent has shown an excellent SPE performance toward sample cleanup by selective elimination of hydrocarbon backgrounds and enrich the CWC related analytes in comparison with the conventional and other reported methods. The best enrichment of the analytes was found with the washing solvent (1 mL of n-hexane) and the extraction solvent (1 mL of dichloromethane). Under the optimized conditions, the SPE method had good linearity in the concentration range of 0.050-10.0 μg mL^-1 for organophosphorus esters, 0.040-20.0 μg mL^-1 for nerve agents, and 0.200-20.0 μg mL^-1 for mustards with correlation coefficients ( r²) between 0.9867 and 0.9998 for all analytes. Limits of detection ( S/ N = 3:1) in the SIM mode were found to be in the range of 0.015-0.050 μg mL^-1 for organophosphorus esters, 0.010-0.030 μg mL^-1 for nerve agents, and 0.050-0.100 μg mL^-1 for blister agents. Limits of quantification ( S/ N = 10:1) were found in the range of 0.050-0.200 μg mL^-1 for organophosphorus esters, 0.040-0.100 μg mL^-1 for nerve agents, and 0.180-0.350 μg mL^-1 for blister agents in the SIM mode. The recoveries of all analytes ranged from 87 to 100% with the relative standard deviations ranging from 1 to 8%. This method was also successfully applied for the sample preparation of ¹H NMR analysis of sulfur and nitrogen mustards in the presence of hydrocarbon backgrounds. Therefore, this SPE method provides the single sample preparation for both NMR and GC-MS analyses.

Mechanism of plant mediated methane emission in tropical lowland rice

Methane (CH₄) is predominantly produced in lowland rice soil, but its emission from soil to atmosphere primarily depends on passage/conduit or capillary pore spaces present in rice plants. The gas transport mechanism through aerenchyma pore spaces of rice cultivars was studied to explore the plant mediated CH₄ emission. Seven rice cultivars, based on the life cycle duration (LCD), were tested in tropical eastern India. Three LCD groups were, (a) Kalinga 1 and CR Dhan 204 (LCD: 110-120 days); (b) Lalat, Pooja and CR 1014 (LCD: 130-150 days); and (c) Durga and Varshadhan (LCD: 160-170 days). Rate of CH₄emission, root exudates, root oxidase activities and shoot aerenchyma pore spaces were analyzed to study the mechanism of plant mediated emission from rice. Aerenchyma pore space was quantified in the hypothesis that it regulates the CH₄ transportation from soil to atmosphere. The ratio of pore space area to total space was lowest in Kalinga 1 cultivar (0.29) and highest was in Varshadhan (0.43). Significant variations in the methane emission were observed among the cultivars with an average emission rate ranged from 0.86 mg m^-2 h^-1 to 4.96 mg m^-2 h^-1. The CH4 emission rates were lowest in short duration cultivars followed by medium and long duration ones. The greenhouse gas intensity considering average CH₄ emission rate per unit grain yield was also lowest (0.35) in Kalinga 1 and relatively less in short and medium duration cultivars. Root exudation was higher at panicle initiation (PI) than maximum tillering (MT) stage. Lowest exudation was noticed in (197.2 mg C plant^-1 day^-1) Kalinga 1 and highest in Varsadhan (231.7 mg C plant^-1 day^-1). So we can say, the rate of CH₄ emission was controlled by aerenchyma orientation, root exudation and biomass production rate which are the key specific traits of a cultivar. Identified traits were closely associated with duration and adaptability to cultivars grown in specific ecology. Therefore, there is possibility to breed rice cultivars depending on ecology, duration and having less CH₄ emission potential, which could be effectively used in greenhouse gas mitigation strategies.

Advancement of puberty and enhancement of seminal characteristics by supplementation of trace minerals to bucks

Attainment of puberty in animals is dependent on their age, body weight, nutritional status, genetic and environmental conditions. Nutritionally, organic minerals are suggested to improve semen production, sperm motility and male fertility. In this context, role of organic zinc (Zn) and copper (Cu) in advancing male puberty and semen characters in Osmanabadi goats were studied. Forty one (n = 41) bucks (Aged 5 months) were divided into ten groups and the dietary treatments comprised of a control group (basal diet; without additional trace mineral supplementation) and nine treatment groups that received, in addition to the basal diet, various doses of trace minerals (mg) on per kg dry matter basis, organic Zn as low Zn20, medium Zn40 and high Zn60, organic Cu as low Cu12.5, medium Cu25, high Cu37.5 and combination of organic Zn + Cu as low Zn20 + Cu12.5, medium Zn40 + Cu25, high Zn60 + Cu37.5, respectively fed for a period of 8 months. Bucks fed organic trace minerals reached puberty 28-35 days earlier than control group. In addition, improvement (P < .01) in testosterone hormone (ng/ml) levels (control: 1.63 ± 0.07 VS Zn60: 2.54 ± 0.02; Cu12.5: 6.17 ± 0.05; Cu25: 3.01 ± 0.04; Cu37.5: 2.39 ± 0.06; Zn20 + Cu12.5: 1.94 ± 0.02; Zn60 + Cu37.5: 2.44 ± 0.16 at 240 days), semen production capacity (sperm concentration, volume, mass motility) and semen quality (higher progressive motility, velocity, sperm membrane integrity and acrosome integrity) were observed in supplemented groups (P < .05) than the control bucks. The present study demonstrated that, additional feeding of organic Zn and Cu to growing male goats advanced onset of puberty and improved quantitative and qualitative semen characteristics. The results also implied that the organic Cu had a significant effect on overall performances of bucks as compared to Zn alone or Zn and Cu in combination.

Metagenomic assessment of methane production-oxidation and nitrogen metabolism of long term manured systems in lowland rice paddy

Biochemical pathways of methanogenesis and methanotrophy coupled with carbon (C)-nitrogen (N) metabolism were studied in long term (13years) manured systems in lowland rice paddy through metagenomics approach. Manured systems included in this study were, control (exclusion of application of any manure), farm yard manure (FYM, @5Mgha^-1yr^-1) and green manuring (GM with Sesbania aculeata). Metagenomic sequence data revealed the dominance of C decomposing bacterial communities' like Proteobacteria, Planctomycetes, Actinobacteria, Firmicutes, Acidobacteria, in manure amended soils as compared to control. Diversities for assimilatory and dissimilatory N-fixing microorganisms at phylum level were found higher under GM as compared to rest. Two genera responsible for methanogenesis, viz. Methanolobus and Methanotorris were absent in manured systems as compared to control. The acetoclastic and serine pathway was found as the predominant pathway for methanogenesis and methanotrophy, respectively, in tropical lowland rice paddy. Abundance reads of enzymes were in the range of 254-445 in the acetoclastic methanogenesis pathway. On the other hand, these were varied from 165 to 216 in serine pathway of methanotrophy. Lowland paddy soil exhibited higher functional and structural diversities in manured systems as compared to unamended control in respect to labile C pools and CH₄ production. Methane (CH₄) emission was 31% higher in FYM system than GM. However, nitrous oxide (N₂O) emission was found 25% higher in GM as compared to FYM. As a whole, bacterial diversities were higher under FYM system in tropical lowland rice paddy as compared to GM and unamended systems.

Elucidation of rice rhizosphere metagenome in relation to methane and nitrogen metabolism under elevated carbon dioxide and temperature using whole genome metagenomic approach

Carbon (C) and nitrogen (N) mineralization is one of the key processes of biogeochemical cycling in terrestrial ecosystem in general and rice ecology in particular. Rice rhizosphere is a rich niche of microbial diversity influenced by change in atmospheric temperature and concentration of carbon dioxide (CO2). Structural changes in microbial communities in rhizosphere influence the nutrient cycling. In the present study, the bacterial diversity and population dynamics were studied under ambient CO2 (a-CO2) and elevated CO2+temperature (e-CO2T) in lowland rice rhizosphere using whole genome metagenomic approach. The whole genome metagenomic sequence data of lowland rice exhibited the dominance of bacterial communities including Proteobacteria, Firmicutes, Acidobacteria, Actinobacteria and Planctomycetes. Interestingly, four genera related to methane production namely, Methanobacterium, Methanosphaera, Methanothermus and Methanothermococcus were absent in a-CO2 but noticed under e-CO2T. The acetoclastic pathway was found as the predominant pathway for methanogenesis, whereas, the serine pathway was found as the principal metabolic pathway for CH4 oxidation in lowland rice. The abundances of reads of enzymes in the acetoclastic methanogenesis pathway and serine pathways of methanotrophy were much higher in e-CO2T (328 and 182, respectively) as compared with a-CO2 (118 and 98, respectively). Rice rhizosphere showed higher structural diversities and functional activities in relation to N metabolism involving nitrogen fixation, assimilatory and dissimilatory nitrate reduction and denitrification under e-CO2T than that of a-CO2. Among the three pathways of N metabolism, dissimilarity pathways were predominant in lowland rice rhizosphere and more so under e-CO2T. Consequently, under e-CO2T, CH4 emission, microbial biomass nitrogen (MBN) and dehydrogenase activities were 45%, 20% and 35% higher than a-CO2, respectively. Holistically, a high bacterial diversity and abundances of C and N decomposing bacteria in lowland rice rhizosphere were found under e-CO2T, which could be explored further for their specific role in nutrient cycling, sustainable agriculture and environment management.

Soil respiration, labile carbon pools, and enzyme activities as affected by tillage practices in a tropical rice-maize-cowpea cropping system

In order to identify the viable option of tillage practices in rice-maize-cowpea cropping system that could cut down soil carbon dioxide (CO2) emission, sustain grain yield, and maintain better soil quality in tropical low land rice ecology soil respiration in terms of CO2 emission, labile carbon (C) pools, water-stable aggregate C fractions, and enzymatic activities were investigated in a sandy clay loam soil. Soil respiration is the major pathway of gaseous C efflux from terrestrial systems and acts as an important index of ecosystem functioning. The CO2-C emissions were quantified in between plants and rows throughout the year in rice-maize-cowpea cropping sequence both under conventional tillage (CT) and minimum tillage (MT) practices along with soil moisture and temperature. The CO2-C emissions, as a whole, were 24 % higher in between plants than in rows, and were in the range of 23.4-78.1, 37.1-128.1, and 28.6-101.2 mg m(-2) h(-1) under CT and 10.7-60.3, 17.3-99.1, and 17.2-79.1 mg m(-2) h(-1) under MT in rice, maize, and cowpea, respectively. The CO2-C emission was found highest under maize (44 %) followed by rice (33 %) and cowpea (23 %) irrespective of CT and MT practices. In CT system, the CO2-C emission increased significantly by 37.1 % with respect to MT on cumulative annual basis including fallow. The CO2-C emission per unit yield was at par in rice and cowpea signifying the beneficial effect of MT in maintaining soil quality and reduction of CO2 emission. The microbial biomass C (MBC), readily mineralizable C (RMC), water-soluble C (WSC), and permanganate-oxidizable C (PMOC) were 19.4, 20.4, 39.5, and 15.1 % higher under MT than CT. The C contents in soil aggregate fraction were significantly higher in MT than CT. Soil enzymatic activities like, dehydrogenase, fluorescein diacetate, and β-glucosidase were significantly higher by 13.8, 15.4, and 27.4 % under MT compared to CT. The soil labile C pools, enzymatic activities, and heterotrophic microbial populations were in the order of maize > cowpea > rice, irrespective of the tillage treatments. Environmental sustainability point of view, minimum tillage practices in rice-maize-cowpea cropping system in tropical low land soil could be adopted to minimize CO2-C emission, sustain yield, and maintain soil health.

Influence of elevated carbon dioxide and temperature on belowground carbon allocation and enzyme activities in tropical flooded soil planted with rice

Changes in the soil labile carbon fractions and soil biochemical properties to elevated carbon dioxide (CO2) and temperature reflect the changes in the functional capacity of soil ecosystems. The belowground root system and root-derived carbon products are the key factors for the rhizospheric carbon dynamics under elevated CO2 condition. However, the relationship between interactive effects of elevated CO2 and temperature on belowground soil carbon accrual is not very clear. To address this issue, a field experiment was laid out to study the changes of carbon allocation in tropical rice soil (Aeric Endoaquept) under elevated CO2 and elevated CO2 + elevated temperature conditions in open top chambers (OTCs). There were significant increase of root biomass by 39 and 44 % under elevated CO2 and elevated CO2 + temperature compared to ambient condition, respectively. A significant increase (55 %) of total organic carbon in the root exudates under elevated CO2 + temperature was noticed. Carbon dioxide enrichment associated with elevated temperature significantly increased soil labile carbon, microbial biomass carbon, and activities of carbon-transforming enzyme like β-glucosidase. Highly significant correlations were noticed among the different soil enzymes and soil labile carbon fractions.

Impact of elevated CO2 and temperature on soil C and N dynamics in relation to CH4 and N2O emissions from tropical flooded rice (Oryza sativa L.)

A field experiment was carried out to investigate the impact of elevated carbon dioxide (CO2) (CEC, 550 μmol mol(-1)) and elevated CO2+elevated air temperature (CECT, 550 μmol mol(-1) and 2°C more than control chamber (CC)) on soil labile carbon (C) and nitrogen (N) pools, microbial populations and enzymatic activities in relation to emissions of methane (CH4) and nitrous oxide (N2O) in a flooded alluvial soil planted with rice cv. Naveen in open top chambers (OTCs). The labile soil C pools, namely microbial biomass C, readily mineralizable C, water soluble carbohydrate C and potassium permanganate oxidizable C were increased by 27, 23, 38 and 37% respectively under CEC than CC (ambient CO2, 394 μmol mol(-1)). The total organic carbon (TOC) in root exudates was 28.9% higher under CEC than CC. The labile N fractions were also increased significantly (29%) in CEC than CC. Methanogens and denitrifier populations in rhizosphere were higher under CEC and CECT. As a result, CH4 and N2O-N emissions were enhanced by 26 and 24.6% respectively, under CEC in comparison to open field (UC, ambient CO2, 394 μmol mol(-1)) on seasonal basis. The global warming potential (GWP) was increased by 25% under CEC than CC. However, emissions per unit of grain yield under elevated CO2 and temperature were similar to those observed at ambient CO2. The stimulatory effect on CH4 and N2O emissions under CEC was linked with the increased amount of soil labile C, C rich root exudates, lowered Eh, higher Fe(+2) concentration and increased activities of methanogens and extracellular enzymes.

Plasma progesterone, oestradiol-17β and total oestrogen profiles in relation to oestrous behaviour during induced ovulation in Murrah buffalo heifers

The objectives of this study were to establish the characteristics of oestrous behaviour in Ovsynch (induction of ovulation through administration of GnRH-PGF2-GnRH in a systemic manner on 0, seventh and ninth day respectively) and Ovsynch plus Norprolac (Quinagolide hydrochloride – an inhibitor of prolactin secretion) treated Murrah buffalo heifers and to determine the relationships between this behaviour and the plasma concentrations of oestradiol-17β (E2), total oestrogen, and progesterone. Oestrus was detected by visual observations of oestrus signs, per rectal examination of genitalia and bull parading thrice a day during treatment period. Among all the symptoms, it was observed that bull mounting of heifers in oestrus was highest. Examination of genital tracts per rectum revealed that the cervix was relaxed, uterus was turgid and ovaries had palpable follicle in animals with oestrus. The peak concentrations of E2 (10.81 ± 0.62 pg/ml) and total oestrogen (17.11 ± 1.21 pg/ml) occurred at 9.45 ± 0.85 and 9.64 ± 0.93 h after second GnRH administration, respectively, in Ovsynch treated animals. However, the peak levels of E2 (20.02 ± 2.87 pg/ml) and total oestrogen (32.71 ± 3.15 pg/ml) occurred at 10.18 ± 0.50 and 10.36 ± 0.75 h after second GnRH administration, respectively, in Ovsynch plus Norprolac treated animals. Plasma progesterone concentration was basal (0.20 ± 0.001 ng/ml) during the peri-oestrus period. The plasma progesterone concentration was the lowest on the day of oestrus and increased to register a peak on day 13 ± 2 of the cycle. Oestrous behaviour was positively correlated with the peak concentration of E2 (p < 0.001) and total oestrogen (p < 0.001) during the peri-oestrus period. Inhibition of prolactin by Norprolac administration significantly increased the concentration of E2 and total oestrogen during oestrus in buffaloes in comparison to those recorded in animals subjected to Ovsynch protocol alone. In conclusion, our results suggest that the peak concentrations of E2 and total oestrogen and mean level of E2 and total oestrogen during the peri-oestrus period are the important factors contributing the behavioural manifestation of oestrus in buffalo cows.

Development and validation of a simple, sensitive enzyme immunoassay (EIA) for quantification of prolactin in buffalo plasma

A simple and highly sensitive enzyme immunoassay (EIA) was developed and validated for prolactin quantification in buffalo plasma (on a microtitreplate) using the biotin-streptavidin-peroxidase amplification and immobilized antiserum in a competitive assay. Prolactin standards (range: 5-5000 pg/(well 50 microL)) were prepared in hormone-free plasma collected from minimal stress non-lactating buffalo heifers in temperate weather. The sensitivity of the EIA procedure was 5 pg/(well 50 microL) (corresponds to 0.1 ng/mL plasma); the 50% relative binding sensitivity occurred at 160 ng/(well 50 microL). Plasma volumes for the EIA, viz. 12.5, 25, and 50 microL, did not influence the shape of standard curve. A parallelism test was carried out to compare the endogenous buffalo plasma prolactin with bovine prolactin standard. To validate the assay biologically, 11 Murrah buffaloes were given a third-generation antiprolactin (Norprolac; 10 mg/animal, i.m.). Blood samples were collected 1 d prior to the start of Norprolac administration and continued up to seventh day in an Ovsynch treatment program. In all animals, there were abrupt declines in prolactin concentrations following Norprolac treatments, which confirmed the biological validation of the EIA. After development and validation of EIA procedure, the concentration of plasma prolactin was determined efficiently in samples collected during both summer and winter samples.

Anatomical study on true hermaphroditism in an Indian pig (Sus scrofa domesticus)

A pig was confirmed to be a true hermaphrodite on the basis of gross and histomorphological studies of the genital organs. The genitalia was consisted of left ovary, oviduct, two coiled uterine horns, body of uterus along with right testis and an epididymis. Vagina and vulva were absent but male urethra with prostate gland was present. Grossly the size of all the genital organs appeared to be normal. Histomorphologically, testis and epididymis were underdeveloped as there was no clearcut spermatogenia and sertoli cells but Leydig cells were normal. The ovary presents normal histological features with some portion of testicular tissue. Degeneration of uterine epithelium was observed along with normal endometrial glands.

A preliminary study on the effect of ultrasound therapy on the healing of surgically severed achilles tendons in five dogs

This study was conducted on the left Achilles tendon in five clinically normal dogs. The Achilles tendon was surgically exposed and severed 3-4 cm proximal to the point of its insertion. Tenorrhaphy was undertaken by the application of three sutures on the various tendon units of the Achilles tendon using single locking-loop sutures with polyamide no. 1-0. The superficial digital flexor tendon was sutured with catgut using two horizontal mattress sutures. No ultrasound therapy was used in the animals of group I (control). Ultrasound therapy was given to the animals of group II (treated) starting from the third day post-operatively at 0.5 W/cm2 for 10 min daily for 10 days. A cortical screw was used for immobilization of the tibiotarsal joint which was removed 4 weeks after tenorrhaphy. Post-operatively, healing of the Achilles tendon was monitored using clinical observations, ultrasonography, gross and histomorphological observations at various intervals up to 120 days in both groups. Clinically, the dogs showed significant lameness for the first 4-5 days, which disappeared earlier in the ultrasound-treated (group II) animals than the controls (group I). Extension and flexion of the hock joint were found to be near normal at 6 weeks after the repair of the Achilles tendon. Ultrasonography showed anechoic to hypo-echoic echo-texture on days 3 and 7 after repair. By day 40, the echo-texture started to improve to hypo-echoic in group II, but in group I anechoic areas were still observed. However, the tendon showed near normal mottled hypo- to hyper-echoic texture in both groups by day 120. Gross observations suggested that the Achilles tendon in group II showed comparatively fewer adhesions than in group I animals. Histologically, in group II (treated), on day 40, the union was comparatively better without any inflammatory reaction. Bundle formation had begun in the ultrasound-treated animals which was not observed in the control animals. By day 90, more compact parallel bundle formation had taken place with minimum cellularity. Bundle formation was in its advanced stage in the treated animals. By day 120, the tendon tissue was comparatively acellular and looking like a normal tendon. The use of the cortical screw provided good immobilization and ultrasound therapy at 0.5 W/cm2 enhanced the Achilles tendon healing in dogs.

Homologous plasma-stored tendon grafting in equids--gross and histomorphological observations

The efficacy of homologous plasma-stored tendon grafting in the superficial digital flexor tendon severed in the mid-metacarpal region was evaluated in 10 donkeys. Experimental tenectomies were performed, followed by grafting using plasma-stored tendon and human amniotic membrane encasement in group I (n=8) but no grafting or encasement in group II (control) (n=2). Gross observations in group I showed no peritendinous adhesions, except in one animal, while control animals showed thick fibrous adhesions and thickening at both the cut ends. Histologically, in the grafted tendon there was normal healing tissue at the junctional sites with negligible collagen fibre and mild regressing inflammatory reaction by day 15. By day 30 there were a great number of blood vessels but without any inflammatory reaction. The healing tissue at the grafted site and the adjoining paratenon was more mature. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. By day 60 fibroblastic activity was negligible and the healing tissue at the distal graft and host tendon junction site was at a more advanced stage of maturation and showed early fasciculi/bundle formation. Healing tissue at three months showed collagen fibres fasciculi/bundle comparable to normal tendon architecture. Tendon appeared histologically normal at four months after grafting.

Histochemical/histoenzymic studies in broiler chicks fed aflatoxin, ochratoxin and inoculated with inclusion body hepatitis virus singly and in concurrence

The effect of feeding mycotoxins, i.e. aflatoxin B1 (1.25 ppm from 3 to 38 days of age) and ochratoxin A (0.5 ppm from 3 to 38 days of age) along with inclusion body hepatitis virus (IBHV) inoculation (at 10 days of age) singly and in combination was studied in broiler chicks. Birds in combined treatment groups, i.e. aflatoxin fed and virus inoculated and ochratoxin fed and virus inoculated, showed more changes in activities of phosphatases (AKPase, ATPase, G-6-Pase and ACPase) in liver and kidney tissues than their respective individual treatment groups with a few exceptions. Reduction in the activities of oxido-reductases in liver and kidney tissues were almost comparable in different treatment groups. The increase in muco-polysaccharides reaction was more marked in both the combined treatment groups than the single treatment groups. Intensity of lipid reaction was more in ochratoxin virus combination group than either alone.

Effect of operation theatre environment on laparotomy wound infection in bovines

Right flank laparotomies were performed on five clinically healthy cross-bred calves. A significant (P less than 0.05) increase of 22.1 and 2.7 times in bacterial count in subcutaneous tissue and incised skin edges, respectively, and a non-significant increase (1.1 times) in muscles and peritoneum had occurred during 15 minutes exposure to the operation theatre environment. Poly-morphonuclear cells and Gram-positive and Gram-negative bacterial infiltration was also demonstrated histopathologically in muscles and peritoneum. Organisms isolated from operation theatre air were Staphylococcus aureus, other Staphylococcus spp., Bacillus spp., Micrococcus spp., and yeast. Usually similar organisms were also found on the laparotomy wound, just before closure of abdomen. Operation theatre environment is concluded to be a significant source of operative wound contamination. Provision of separate operation theatres for different types of surgery in different species is recommended and the necessity for their regular disinfection is stressed.

Gross and histopathological observations on the effects of therapeutic ultrasound in experimental acute chemical arthritis in calves

Acute chemical arthritis was induced in right radiocarpal joints of eight cow calves by intraarticular injections of turpentine oil. They were randomly divided into two groups A and B of four calves each. Group A served as control. Group B was given therapeutic ultrasound at 2.0W/cm2 for 7 minutes daily for 7 days starting on day 5. On day 19, all the calves of both the groups were slaughtered. Grossly as well as microscopically, joint tissues of group A calves showed severe inflammatory and degenerative changes. Joint capsule of group B calves showed regeneration of synovial membrane and articular cartilage was normal grossly as well as microscopically.

Histomorphochemical effects of shortwave diathermy on healing of experimental muscular injury in dogs

The biceps femoris muscle was surgically incised and sutured in 10 clinically healthy mongrel dogs, aged 1-2 yr and weighing 10-15 kg. The surgical wounds of 5 dogs were exposed to shortwave diathermy for 5 min daily for 7 days, starting a day after the creation of trauma. The remaining 5 dogs served as control. After 15 days of healing, the tissues from biceps femoris muscle were collected and subjected to histomorphological and histochemical examination. Mature collagen bundles were seen at healing site in diathermy treated animals while there were immature collagen fibres and more number of fibroblasts in control animals. Normal muscle fibres could be seen on either side of the healing tissue in treated animals whereas in control animals, atrophied and necrosed muscle fibres were encountered. The neutral and acid mucopolysaccharides, lipid droplets in the intermyofibrillar area and the activity of alkaline phosphatase, adenosine triphosphatase and lactate dehydrogenase at the healing site was better in treated as compared to controls.