Genetic variations among the isolates of Bipolaris Maydis based on phenotypic and molecular markers

Abstract Maydis leaf blight, caused by Bipolaris maydis, is an important disease of maize crop in Khyber Pakhtunkhwa (KP) Pakistan. Fifteen isolates of the pathogen, collected across KP, were studied for variability based on phenotypic and molecular markers. Significant variability among the isolates was observed when assessed using phenotypic traits such as radial growth, spore concentration, fungicide sensitivity and virulence. The isolates were classified into six culture groups based on colour, texture and margins of the colony. Conidial morphology was also variable. These were either straight or slightly curved and light to dark brown in colour. Fungicide test showed significant variation in the degree of sensitivity against Carbendazim. Isolate Bm8 exhibited maximum radial growth on carbendazim spiked plates. Conversely, isolate Bm15 showed the lowest radial growth. Variations in virulence pattern of the isolates were evident when a susceptible maize variety Azam was inoculated with spores of B. maydis. Genetic variability amongst the isolates was also estimated by RAPD as well as sequencing of ITS region. The RAPD dendrogram grouped all the isolates into two major clusters. Average genetic distance ranged from 0.6% to 100%, indicating a diverse genetic gap among the isolates. Maximum genetic distance was found between isolates Bm9 and Bm10 as well as Bm2 and Bm8. Conversely, isolates Bm13 and Bm15 were at minimum genetic distance. Phylogenetic dendrogram based on sequencing of ITS region grouped all the isolates into a single major cluster. The clusters in both the dendrogram neither correlate to the geographical distribution nor to the morphological characteristics.

The small molecule Erk1/2 signaling pathway inhibitor PD98059 improves DNA repair in an experimental autoimmune encephalomyelitis SJL/J mouse model of multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disorder in which the myelin sheath covering the central nervous system axons is damaged or lost, disrupting action potential conduction and leading to various neurological complications. The pathogenesis of MS remains unclear, and no effective therapies are currently available. MS is triggered by environmental factors in genetically susceptible individuals. DNA damage and DNA repair failure have been proposed as MS genetic risk factors; however, inconsistent evidence has been found in multiple studies. Therefore, more investigations are needed to ascertain whether DNA damage/repair is altered in this disorder. In this context, therapies that prevent DNA damage or enhance DNA repair could be effective strategies for MS treatment. The overactivation of the extracellular-signal-related kinase 1 and 2 (Erk1/2) pathway can lead to DNA damage and has been linked to MS pathogenesis. In our study, we observed substantially elevated oxidative DNA damage and slower DNA repair rates in an experimentally autoimmune encephalomyelitis animal model of MS (EAE). Moreover, statistical decreases in oxidative DNA strand breaks and faster repair rates were observed in EAE animals injected with the Erk1/2 inhibitor PD98059 (PD). Moreover, the expression of several genes associated with DNA strand breaks and repair changed in EAE mice at both the mRNA and protein levels, as revealed by the RT² Profiler PCR array and verified by RT-PCR and protein analyses. The treatment with PD mitigated these changes and improved DNA repair gene expression. Our results demonstrate clear associations between Erk1/2 activation, DNA damage/repair, and MS pathology, and further suggest that PD therapy may be a promising adjuvant therapeutic strategy.

Effect of natural and synthetic androgen hormone on sex reversal of Nile Tilapia (Oreochromis niloticus)

The present study aimed to produce a monosex population of all male Nile tilapia (Oreochromis spp.) using 17α-methyl testosterone and common carp testes (as a source of natural androgen). Trial was conducted into two consecutive phases, the first was fry (4-5 days old)administration with negative control (without hormone) and positive control (with hormone) feed viz., MT1:60mg/kg, MT2:70mg/kg (17α-MT), carp testis CT1:70% and CT2:80% for 30 days to reverse the sex of male fish and the second phase was nursing the fingerlings for two months on control diet (32% Crude protein).Results revealed a significant growth rate (P<0.05) in the control group where final weight (4.8±0.34ab) and weight gained was recorded as 0.66±0.03ac. In proximate chemical composition of body meat, CT2 treatment showed maximum retention of crude protein, crude fat, and ash whereas dry matter showed maximum retention in MT2 and CT1 treatments. Morphological and histological examination revealed significant difference (p<0.05) in phenotypic males of Nile tilapia fed with the highest percent in MT-treated diet (MT2) of 95±0.58a while MT1, CT2 and CT1 had males of 85±6.0b, 70±5.0b and 65±6.5b, respectively. It was concluded that synthetic androgen (17αMT) was more effective for masculinization but natural androgen scan be an alternative method to produce male tilapia population in an environment-friendly manner as they are inexpensive, eco-friendly, and radially available. These results suggested that synthetic and natural androgen supplementation in the diet plays a significant role in improving growth performance and body composition.

Concurrent Obsessive-Compulsive Symptoms in Patients With Schizophrenia: A Retrospective Study From a Tertiary Care Centre in Sindh, Pakistan

INTRODUCTION

The present study aimed to evaluate the proportion of concurrent symptoms of obsessive-compulsive symptoms (OCSs) among patients with schizophrenia.

METHODS

A retrospective study was undertaken at the Department of Psychiatry, Jinnah Postgraduate Medical Center, Sindh, Pakistan between 1st March 2019 and 1st April 2020. All cases with diagnosed schizophrenia irrespective of gender, age, or ethnicity were eligible for the study. We excluded patients with acute psychosis due to isolated substance use disorder or any organic brain disease. The medical records for each patient were retrieved from the departmental database. Sociodemographic factors including age, gender, ethnicity, and presence of OCSs and other psychiatric comorbidities were recorded in a predefined pro forma. The presence of OCSs was noted by the attending psychiatrist during history taking as positive or negative.

RESULTS

A total of 139 patients were included. A predominance of the male gender was noted. There were 63 (45.3%) patients with concurrent OCSs. Out of the total patients, 42 (66.67%) males and 21 (33.33%) females had OCSs. A total of 28 (44.44%) patients between 31 and 45 years of age had OCSs. Out of the 63 patients with OCSs, 36 (57.14%) had a history of substance abuse (p = 0.471). In the study, 17 (26.98%) Balochi and 19 (30.16%) Pashtuns had OCSs. However, the difference was statistically insignificant.

CONCLUSION

In conclusion, OCSs were frequent in patients with schizophrenia, according to the current study. We discovered that males, individuals between the ages of 18 and 30 years, Balochis, Pashtuns, and those with a history of substance abuse were more likely to have OCSs. However, the difference was not statistically significant.

Multiple exposure to methylmercury aggravates DNA damage in the BTBR T + Itpr3 tf/J autistic mouse model: the role of DNA repair efficiency

Environmental and genetic factors have been recognized to play major roles in the pathogenesis of autism. Here we examined the BTBR T⁺Itpr3^tf/J (BTBR) mice's susceptibility, an autistic model, to the genotoxic effects and DNA repair dysregulation of methylmercury. Micronuclei formation and oxidative DNA damage were analyzed using the micronucleus/fluorescence in situ hybridization test and modified comet assay, respectively. The results showed higher centromeric-positive micronuclei and oxidative DNA damage in BTBR mice exposed to methylmercury than the unexposed mice, which indicates that mutagenesis aggravated in BTBR mice after methylmercury exposure. Lipid peroxides in BTBR mice were significantly elevated, with a decrease in reduced/oxidized glutathione ratio after methylmercury exposure, indicating an augmenting oxidant-antioxidant imbalance. The expression of several genes involved in DNA repair was markedly altered in BTBR mice after methylmercury exposure as evaluated via PCR array and RT-PCR analyses. Declining of the antioxidant defense and dysregulation in DNA repair process after methylmercury exposure may explain the aggravated genotoxic susceptibility of BTBR mice. Thus, autistic individuals exposed to methylmercury must be under regular medical follow-up through standard timetabled medical laboratory inquiry to allow for early recognition of any mutagenic changes. Additionally, strategies that elevate cellular antioxidants/DNA repair efficiency may counteract methylmercury-induced genotoxicity.

The Association Between Deficiency of Vitamin D and Diabetes Mellitus Type 2 (DMT2)

Background 

The impact of vitamin D deficiency on the incidence of various diseases and its relationship with the progression of diabetes mellitus type 2 (DMT2) is still controversial. The present study evaluated the incidence of vitamin D deficiency in patients with DMT2.

Methodology 

A cross-sectional study was conducted in a tertiary care hospital, Sindh, Pakistan from October 2020 to September 2021. A total of 525 patients of DMT2 were recruited. Another 525 patients acted as healthy controls. In patients with DMT2, blood samples were taken in the morning to measure vitamin D levels. All socio-demographic and clinical data were documented in a predefined pro forma. The association between the incidence of DMT2 and hypovitaminosis was explored. 

Results

The mean age of the patients was 50 ± 5.5 years. There were 100 (54.1%) male and 85 (45.9%) female patients. The mean duration of diabetes of the patients was 6.8 ± 2.4 years. The mean serum 25-hydroxy vitamin D level was 22.3 ±10.4 ng/ml. In the case group, the majority of the patients had vitamin D deficiency i.e. 54.1%, while only 25.9% of controls had hypovitaminosis. Vitamin D deficiency was significantly correlated with the occurrence of DMT2 (p<0.0001). 

Conclusion

The current study indicates that patients with diabetes mellitus type 2 (DMT2) more frequently suffer from vitamin D deficiency. Those patients with vitamin D deficiency and DMT2 can benefit from vitamin D replenishment. This may help improve glycemic control in these patients. This study served as a catalyst for future studies where the relationship between hypovitaminosis and insulin resistance can be thoroughly explored. 

Plant age, crop stage and surrounding habitats: their impact on sucking pests and predators complex in cotton (Gossypium hirsutum L.) field plots in arid climate at district Layyah, Punjab, Pakistan

Sucking pests are major threat to cotton field crop which cause unbearable losses to the crop yield. Aim of the current study was to record seasonal dynamics of major sucking insect pests including whitefly, jassid, thrips and their natural arthropod predators i.e. green lacewings and spiders in cotton field plots. The effects of surrounding field crops on pests' density and predatory efficiency of predators were also recorded. For sampling and survey of insects, the visual counting was found to be the most efficient method for recording the abundance of insects, trailed by net sweeping and tapping. Whitefly was the most dominant sucking pest found on the vegetative stage of cotton, followed by jassid and thrips. Fluctuated populations of predatory arthropods, spiders and green lacewings were also recorded during whole cropping season however, the densities of pests and predators varied with crop phenology. Spiders' population was encouraging at both vegetative and flowering stage and also the same trend of jassid and whitefly were observed at both stages of the crop. Surrounding habitats showed non-significant effect on population densities of insect pests and predators. For abiotic factors, the spiders showed strong positive correlation with humidity and temperature. However, green lacewing was only positively correlated with humidity. On the other hand, the populations of whitefly, jassid and thrips showed non-significant correlation with both temperature and humidity. Overall densities of sucking insect pests were found above economic threshold level. The plant age, crop stage and surrounding habitats effect on the population fluctuation of pests as well as the predators' abundance. The future studies are also warranted to investigate the altered habitats and multiple trap cropping to find out their impact on unattended insect predators and parasitoids in cotton crop.

SNP discovery and population structure analysis in Lassi and Marecha camel breeds using a genotyping by sequencing method

Pakistani camels have been classified socio-geographically into 20 breeds, but they have not yet been subjected to substantial selective pressures and the genetic basis for these breeds is not understood. However, it should be possible to distinguish them by use of molecular data. This study investigated the genetic diversity and population structure within and between two major Pakistani camel breeds, Marecha and Lassi. As no SNP array is currently available, we first identified 63 619 SNPs using a genotyping by sequencing approach. After quality control, a panel of 36 926 SNPs was used in the analysis. Population structure was investigated with a principal coordinate analysis as well as a cluster analysis using NetView, and multilocus heterozygosity analysis to explore between- and within-breed genetic variation. In addition, between-breed variation was explored using the fixation index, F_ST . We also compared relationship matrices computed using the VanRaden SNP-based method and a method developed specifically for genotyping by sequencing data. Among the two camel breeds, Lassi showed a lower level of genetic diversity whereas Marecha showed a higher level. As a genotyping platform has not yet been developed for the camel, the SNPs discovered in this study will be useful in future genetic studies in camels.

Identification of novel single nucleotide polymorphisms in the PRKAG3 gene of Pakistani river buffalo

Pakistani river buffalo is classified in five breeds out of which Kundi buffalo has been least documented. This study is designed to find single nucleotide polymorphisms (SNPs) in exonic and in-tronic regions of PRKAG3 (AMP-activated, Gamma3 non-catalytic subunit) gene in the Kundi buf-falo. The PRKAG3 gene of 95 animals each from Kundi and Nili-Ravi were sequenced for identifica-tion of novel SNPs. Comparing with the Nili Ravi breed of buffalo PRKAG3 gene, six SNP sites were identified in the Kundi buffalo. The novel SNPs found in this work can function as a genomic indicator for genetic-phenotypic relationship of PRKAG3 gene with milk and meat production in buffalo. This is the first report of SNPs in PRKAG3 gene of Kundi Buffalo.

Assessment of DNA repair efficiency in the inbred BTBR T+tf/J autism spectrum disorder mouse model exposed to gamma rays and treated with JNJ7777120

Information regarding DNA repair in autism is limited to a few studies, which have reported inconsistent results. Therefore, we designed a study to determine whether DNA repair efficiency is altered in autism and to investigate whether the H₄ ligand JNJ7777120 can enhance DNA repair efficiency in BTBR T⁺tf/J (BTBR) mice; we also attempted to elucidate the mechanism(s) underlying this amelioration. Evaluation of DNA damage using the comet assay on bone marrow cells showed increased levels of DNA damage in BTBR mice compared with age-matched control C57BL/6J mice. Conversely, BTBR animals pretreated with 20 mg/kg JNJ7777120 for five days exhibited significant decreases in DNA damage compared with that of control BTBR mice. Our results also indicated higher sensitivity of BTBR mice exposed to gamma rays to DNA damage generation. A marked difference was observed between BTBR and C57BL/6J mice at different sampling times after irradiation, with BTBR mice showing a higher percentage of DNA damage and slower repair rate than that of C57BL/6J mice. JNJ7777120 led to enhanced repair of the DNA damage induced by radiation when administered to BTBR mice five days prior to radiation. Additionally, oxidative stress in BTBR mice was significantly elevated with a reduced GSH/GSSG ratio; significant amelioration was subsequently observed in JNJ7777120-pretreated BTBR mice. Furthermore, repetitive behaviors were also attenuated in BTBR mice by JNJ7777120 treatment without altering locomotor activity. Our results suggest that JNJ7777120 can be developed for use as a therapeutic agent to enhance DNA repair efficiency in autism spectrum disorder.

Investigation of belinostat-induced genomic instability by molecular cytogenetic analysis and pathway-focused gene expression profiling

Histone deacetylases (HDACs), which regulate transcription and specific functions such as tumor suppression by p53, are frequently altered in tumors and have a contentious role in carcinogenesis. HDAC inhibitors, which have a long history of use in psychiatry and neurology, have recently been tested as possible treatments for tumors. Belinostat received regulatory approval in the USA on July 3, 2014, for use against peripheral T-cell lymphoma. However, the unavailability of information on belinostat genotoxicity in normal cells and the molecular mechanisms involved in the genetic instability after exposure to belinostat encouraged us to conduct this study. Our data showed that the exposure of mice to belinostat at the recommended human doses induced chromosome breakage, whole-chromosome lagging, and oxidative DNA damage in bone marrow cells in a dose-dependent manner. The expression levels of 84 genes involved in the DNA damage signaling pathway were evaluated by using an RT² Profiler PCR array. Belinostat exposure altered the expression of 25 genes, with statistically significant changes observed in 17 genes. The array results were supported by RT-PCR and western blotting experiments. Collectively, our results showed that belinostat exposure caused oxidative DNA damage and downregulated the expression of genes involved in DNA damage repair, which may be responsible for belinostat-induced genomic instability. Thus, the clinical usage of this drug should be weighed against the hazards of carcinogenesis, and the observed genotoxicity profile of belinostat may support further development of efficient HDAC inhibitors with weaker genotoxicity.

Glucose-6-phosphate dehydrogenase inhibition attenuates acute lung injury through reduction in NADPH oxidase-derived reactive oxygen species

Acute lung injury (ALI) is a heterogeneous disease with the hallmarks of alveolar capillary membrane injury, increased pulmonary oedema and pulmonary inflammation. The most common direct aetiological factor for ALI is usually parenchymal lung infection or haemorrhage. Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) are thought to play an important role in the pathophysiology of ALI. Glucose-6-phosphate dehydrogenase (G6PD) plays an important role both in production of ROS as well as their removal through the supply of NADPH. However, how G6PD modulation affects NOX2-mediated ROS in the airway epithelial cells (AECs) during acute lung injury has not been explored previously. Therefore, we investigated the effect of G6PD inhibitor, 6-aminonicotinamide on G6PD activity, NOX2 expression, ROS production and enzymatic anti-oxidants in AECs in a mouse model of ALI induced by lipopolysaccharide (LPS). ALI led to increased G6PD activity in the AECs with concomitant elevation of NOX2, ROS, SOD1 and nitrotyrosine. G6PD inhibitor led to reduction of LPS-induced airway inflammation, bronchoalveolar lavage fluid protein concentration as well as NOX2-derived ROS and subsequent oxidative stress. Conversely, ALI led to decreased glutathione reductase activity in AECs, which was normalized by G6PD inhibitor. These data show that activation of G6PD is associated with enhancement of oxidative inflammation in during ALI. Therefore, inhibition of G6PD might be a beneficial strategy during ALI to limit oxidative damage and ameliorate airway inflammation.

Prophage as a genetic reservoir: Promoting diversity and driving innovation in the host community

Sequencing of bacterial genomes has revealed an abundance of prophage sequences in many bacterial species. Since these sequences are accessible, through recombination, to infecting phages, bacteria carry an arsenal of genetic material that can be used by these viruses. We develop a mathematical model to isolate the effects of this phenomenon on the coevolution of temperate phage and bacteria. The model predicts that prophage sequences may play a key role in maintaining the phage population in situations that would otherwise favor host cell resistance. In addition, prophage recombination facilitates the existence of multiple phage types, thus promoting diverse co-existence in the phage-host ecosystem. Finally, because the host carries an archive of previous phage strategies, prophage recombination can drive waves of innovation in the host cell population.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Functional inhibition of PAR2 alleviates allergen-induced airway hyperresponsiveness and inflammation

BACKGROUND

Proteinase-activated receptor 2 (PAR2 ) is a G protein-coupled receptor activated by trypsin-like serine proteinases. PAR2 activation has been associated with inflammation including allergic airway inflammation. We have also shown that PAR2 activation in the airways leads to allergic sensitization. The exact contribution of PAR2 in the development of eosinophilic inflammation and airway hyperresponsiveness (AHR) in sensitized individuals is not clear.

OBJECTIVE

To investigate whether functional inhibition of PAR2 during allergen challenge of allergic mice would inhibit allergen-induced AHR and inflammation in mouse models of asthma.

METHODS

Mice were sensitized and challenged with ovalbumin (OVA) or cockroach extract (CE). To investigate the role of PAR2 in the development of AHR and airway inflammation, we administered blocking anti-PAR2 antibodies, or a cell permeable peptide inhibitor of PAR2 signalling, pepducin, i.n. before allergen challenges and then assessed AHR and airway inflammation.

RESULTS

Administration of anti-PAR2 antibodies significantly inhibited OVA- and CE-induced AHR and airway inflammation. In particular, two anti-PAR2 antibodies, the monoclonal SAM-11 and polyclonal B5, inhibited AHR, airway eosinophilia, the increase of cytokines in the lung tissue and antigen-specific T cell proliferation, but had no effect on antigen-specific IgG and IgE levels. Pepducin was also effective in inhibiting AHR and airway inflammation in an OVA model of allergic airway inflammation.

CONCLUSIONS AND CLINICAL RELEVANCE

Functional blockade of PAR2 in the airways during allergen challenge improves allergen-induced AHR and inflammation in mice. Therefore, topical PAR2 blockade in the airways, through anti-PAR2 antibodies or molecules that interrupt PAR2 signalling, has the potential to be used as a therapeutic option in allergic asthma.

Targeting of nucleotide-binding proteins by HAMLET--a conserved tumor cell death mechanism

HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) kills tumor cells broadly suggesting that conserved survival pathways are perturbed. We now identify nucleotide-binding proteins as HAMLET binding partners, accounting for about 35% of all HAMLET targets in a protein microarray comprising 8000 human proteins. Target kinases were present in all branches of the Kinome tree, including 26 tyrosine kinases, 10 tyrosine kinase-like kinases, 13 homologs of yeast sterile kinases, 4 casein kinase 1 kinases, 15 containing PKA, PKG, PKC family kinases, 15 calcium/calmodulin-dependent protein kinase kinases and 13 kinases from CDK, MAPK, GSK3, CLK families. HAMLET acted as a broad kinase inhibitor in vitro, as defined in a screen of 347 wild-type, 93 mutant, 19 atypical and 17 lipid kinases. Inhibition of phosphorylation was also detected in extracts from HAMLET-treated lung carcinoma cells. In addition, HAMLET recognized 24 Ras family proteins and bound to Ras, RasL11B and Rap1B on the cytoplasmic face of the plasma membrane. Direct cellular interactions between HAMLET and activated Ras family members including Braf were confirmed by co-immunoprecipitation. As a consequence, oncogenic Ras and Braf activity was inhibited and HAMLET and Braf inhibitors synergistically increased tumor cell death in response to HAMLET. Unlike most small molecule kinase inhibitors, HAMLET showed selectivity for tumor cells in vitro and in vivo. The results identify nucleotide-binding proteins as HAMLET targets and suggest that dysregulation of the ATPase/kinase/GTPase machinery contributes to cell death, following the initial, selective recognition of HAMLET by tumor cells. The findings thus provide a molecular basis for the conserved tumoricidal effect of HAMLET, through dysregulation of kinases and oncogenic GTPases, to which tumor cells are addicted.

Oxidative airway inflammation leads to systemic and vascular oxidative stress in a murine model of allergic asthma

Oxidant-antioxidant imbalance plays an important role in repeated cycles of airway inflammation observed in asthma. It is when reactive oxygen species (ROS) overwhelm antioxidant defenses that a severe inflammatory state becomes apparent and may impact vasculature. Several studies have shown an association between airway inflammation and cardiovascular complications; however so far none has investigated the link between airway oxidative stress and systemic/vascular oxidative stress in a murine model of asthma. Therefore, this study investigated the contribution of oxidative stress encountered in asthmatic airways in modulation of vascular/systemic oxidant-antioxidant balance. Rats were sensitized intraperitoneally with ovalbumin (OVA) in the presence of aluminum hydroxide followed by several intranasal (i.n.) challenges with OVA. Rats were then assessed for airway and vascular inflammation, oxidative stress (ROS, lipid peroxides) and antioxidants measured as total antioxidant capacity (TAC) and thiol content. Challenge with OVA led to increased airway inflammation and oxidative stress with a concomitant increase in vascular inflammation and oxidative stress. Oxidative stress in the vasculature was significantly inhibited by antioxidant treatment, N-acetyl cysteine; whereas hydrogen peroxide (H2O2) inhalation worsened it. Therefore, our study shows that oxidative airway inflammation is associated with vascular/systemic oxidative stress which might predispose these patients to increased cardiovascular risk.

Identification of a novel mutation (p.Ile198Thr) in gene TYR in a Pakistani family with nonsyndromic oculocutaneous albinism

The TYR gene (MIM #6069333) is located at position 11q14.3 on the human chromosome, and encodes tyrosinase, which is expressed in melanocytes and controls the biosynthesis of melanin. Most TYR mutations eliminate the activity of tyrosinase, preventing melanocytes from producing any melanin throughout life. People with this form of albinism have white hair, light-coloured eyes and very pale skin. Some mutations in TYR reduce but do not completely eliminate tyrosinase activity, and allow some melanin to be produced. We report a Pakistani family with four members affected by oculocutaneous albinism (OCA). Blood samples were collected from all affected individuals, normal siblings and their parents. Genomic DNA was extracted, and sequence analysis of all the coding exons and adjacent intronic sequences of TYR was performed, which identified a novel missense substitution (p.Ile198Thr). Sequencing of TYR in 90 unrelated healthy individuals showed no sequence variant at this location. Our study expands the mutational spectrum of OCA1.

Effect of the apoptosis signal ceramide (C6) on antitumor activity of chemotherapeutic agents in SCID mice

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Introduction: The ceramides are a major signaling pathway for apoptosis in cells undergoing stress or exposure to chemotherapy. We have demonstrated synergistic anti-tumor effects of combining C6 ceramide with paclitaxel, doxorubicin and cisplatin and are currently addressing the question; does C6 augment activity of all the major classes of drugs? Backround: Currently the in vivo anti-tumor effects of C6 with oxaliplatin and Gemcitabine. Methods: Invivo experiments SCID/Beige/Taconic male mice inoculated S.C. with 2X106 L3.6 pancreatic cells were treated 4 days post tumor implant with trice weekly (3x/wk) intraperitoneal (IP) injections of paclitaxel (P) 3.0 m/kg, oxaliplatin (OX) 2.5 mg/kg, cisplatin (CP) 2.5 mg/kg, Gemcitabine (Gem) 10 mg/kg with/without ceramide 10 mg/kg. Mice were observed for 6 weeks and were autopsied when near death. (All controls died by 3rd week). Maximum tumor volume, tumor weight; body weight and survival were recorded. Results: Combination with C6 ceramide augmented the tumor reduction obtained by chemotherapy alone by 57% (while preserving body weight), and increased 6 week survival from 0% (Chemotherapy alone) to 60% with combined therapy. Mean survival was increased from 25 to 37 days. Although short term immunohistochemical studies suggested enhanced apoptosis and increased caspase 3 production by ceramide combinations it may actually be independent of capase activation and mitochondrial activation. Conclusions: Combination therapy with the apoptotic signal C6 ceramide significantly enhanced the anti-tumor effects of the anti microtubule, alkylating Paclitaxel a DNA interculating antibiotic (doxorubicin) the alkylating/DNA adducting agents (cisplatin, oxaliplatin) and an anti metabolite (gemcitabine) suggesting generation of broad based apoptotic signals which interact with major cancer drug classes (tested).

No significant financial relationships to disclose.

A2A adenosine receptor deficiency leads to impaired tracheal relaxation via NADPH oxidase pathway in allergic mice

A(2A) adenosine receptor (A(2A)AR) has been shown to suppress superoxide generation in leukocytes via the cAMP-protein kinase A (PKA) pathway. However, no study has yet explored the role of A(2A)AR in relation to NADPH oxidase in murine tracheas in vitro, which may lead to altered smooth muscle relaxation in asthma. Therefore, the present study evaluated the effects of A(2A)AR deficiency on the NADPH oxidase pathway in tracheas of A(2A) wild-type (WT) and A(2A) knockout (KO) mice. A(2A)WT mice were sensitized with ovalbumin (30 microg i.p.) on days 1 and 6, followed by 5% ovalbumin aerosol challenge on days 11, 12, and 13. A(2A)AR (gene and protein expression), cAMP, and phosphorylated PKA (p-PKA) levels were decreased in A(2A)WT sensitized mice compared with controls. A(2A)KO mice also showed decreased cAMP and p-PKA levels. A(2A)WT sensitized and A(2A)KO control mice had increased gene and protein expression of NADPH oxidase subunits (p47phox and gp91phox) compared with the controls. Tracheal relaxation to specific A(2A)AR agonist, 4-[2-[[6-amino-9-(N-ethyl-beta-d-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS 21680), decreased in A(2A)WT sensitized mice compared with the controls, although it was absent in A(2A)KO mice. Pretreatment with NADPH oxidase inhibitors apocyanin/diphenyliodonium reversed the attenuated relaxation to CGS 21680 in A(2A)WT sensitized tracheas, whereas specific PKA inhibitor (9S,10S,12R)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i] [1,6]benzodiazocine-10-carboxylic acid hexyl ester (KT 5720) blocked CGS 21680-induced relaxation. Tracheal reactive oxygen species (ROS) generation was also increased in A(2A)WT sensitized and A(2A)KO control mice compared with the controls. In conclusion, this study shows that A(2A)AR deficiency causes increased NADPH oxidase activation leading to decreased tracheal relaxation via altered cAMP-PKA signaling and ROS generation.

Effect of vitamin E supplementation with standard treatment on oxidant-antioxidant status in chronic obstructive pulmonary disease

BACKGROUND & OBJECTIVES

Chronic oxidant burden and depletion of endogenous antioxidants have been proposed to play a key role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Exogenous antioxidants have potential therapeutic implications and their role has not been explored in COPD. The objective of this study was to investigate the effect of supplementation of standard treatment (inhaled long-acting beta(2) agonists, anticholinergics and corticosteroids) with vitamin E on oxidant-antioxidant balance in patients with COPD.

METHODS

The study was carried out in the outpatient setting. Patients were divided into two groups: group A- placebo group (n=14), receiving only standard therapy, and group B- vitamin E-supplemented group (n=10), receiving 400 IU of vitamin E capsules twice daily in addition to standard therapy. Spirometry and clinical assessment were carried out at the start and completion of 8 wk treatment along with measurements of several biochemical parameters of oxidant-antioxidant status in plasma, leukocytes and red cells separated from venous blood.

RESULTS

Leukocyte superoxide generation was decreased in both the groups. Vitamin E-supplemented group had significantly increased levels of plasma sulphydryls and red cell catalase while the placebo group had decreased levels of plasma nitrates and nitrites. No significant differences were observed in red cell superoxide dismutase and glutathione peroxidase activities, total blood glutathione, and plasma total antioxidant capacity, lipid peroxides and glutathione peroxidase activity in either group. There was a similar degree of lung function and clinical improvement in both the groups.

INTERPRETATION & CONCLUSION

Our findings showed that an 8 wk supplementation of standard treatment with 400 IU twice daily of vitamin E did not provide any additional clinical benefit although it augmented certain endogenous antioxidants in patients with COPD.

Effect of potassium chloride supplementation in drinking water on broiler performance under heat stress conditions

The effect of water supplementation of KCl on performance of heat-stressed Hubbard broilers was evaluated in the present experiment. The 3 experimental treatments (i.e., control, 0.3 and 0.6% KCl) were allocated to 3 replicates of 15 birds each. The control group was kept on dugout tap water, whereas the other 2 groups were supplied water supplemented with 0.3 and 0.6% KCl (wt/vol) by supplementing 3 and 6 g of KCl, respectively, per liter of drinking water. Broilers were provided ad libitum access to feed and water for the experimental period of 7 to 42 d of age and kept in open-sided house. The birds were reared under continuous thermostress (minimum 28.2 +/- 1.02 and maximum 37.5 +/- 0.78 degrees C) environment. Supplementing drinking water with 0.6% KCl reduced panting-phase blood pH to 7.31 and significantly increased live BW gain by 14.5 (P = 0.036) and 7.9% (P = 0.029) at 28 and 42 d of age, respectively, relative to control. An improved (P = 0.04) feed:gain and lowered body temperature were noted in groups supplemented with 0.6% KCl as compared with control and 0.3% KCl. Enhanced physiological adaptation with 0.6% KCl was evidenced by a more favorable pH during the panting phase in the present study. These findings demonstrated a possibility of better broiler live performance through KCl supplementation under conditions of severe heat stress (35 to 38 degrees C).

Less tongue engorgement with lateral placement of the Esophageal Tracheal Combitube

BACKGROUND

The conventional technique of insertion and fixation of the Esophageal Tracheal Combitube (ETC) is occasionally associated with engorgement of the tongue. This study sought to evaluate the efficacy of an alternative placement technique in reducing the incidence of this complication.

METHODS

Thirty ASA I and II adult patients posted for elective surgery under general anaesthesia lasting from 30 to 120 min were randomly divided into two groups (n=15, each). In Group A, the ETC was inserted and fixed in the midline. In Group B, the ETC was inserted along the angle of the mouth and was fixed at this lateral position. Intra-operative occurrence of engorgement of the tongue, the time of such an occurrence and any complaints of post-operative discomfort were recorded.

RESULTS

The overall incidence of engorgement of the tongue in Group A patients (67%) was significantly more (P<0.01) as compared with Group B (17%). The incidence significantly increased (P<0.01) with an increase in the duration of surgery in both the groups. The engorgement persisted into the post-operative period in three patients in Group A and resolved spontaneously in <15 min in each case.

CONCLUSION

Lateral insertion and fixation of the ETC is an easy, safe and effective method of preventing engorgement of the tongue associated with the use of this device without compromising a leak-proof oropharyngeal cavity.

A novel A1 adenosine receptor antagonist, L-97-1 [3-[2-(4-aminophenyl)-ethyl]-8-benzyl-7-{2-ethyl-(2-hydroxy-ethyl)-amino]-ethyl}-1-propyl-3,7-dihydro-purine-2,6-dione], reduces allergic responses to house dust mite in an allergic rabbit model of asthma

Adenosine, an important signaling molecule in asthma, produces bronchoconstriction in asthmatics. Adenosine produces bronchoconstriction in allergic rabbits, primates, and humans by activating A1 adenosine receptors (ARs). Effects of L-97-1 [3-[2-(4-aminophenyl)-ethyl]-8-benzyl-7-{2-ethyl-(2-hydroxyethyl)-amino]-ethyl}-1-propyl-3,7-dihydro-purine-2,6-dione] a water-soluble, small molecule A1 AR antagonist were investigated on early and late phase allergic responses (EAR and LAR) in a hyper-responsive rabbit model of asthma. Rabbits were made allergic by intraperitoneal injections of house dust mite [HDM; 312 allergen units (AU)] extract within 24 h of their birth. Booster HDM injections were given weekly for 1 month, biweekly for 4 months, and continued monthly thereafter. Hyperresponsiveness was monitored by measuring lung dynamic compliance (Cdyn), after histamine or adenosine aerosol challenge in allergic rabbits. Hyper-responsive rabbits were subjected to aerosol of HDM (2500 AU), 1 h after intragastric administration of L-97-1 (10 mg/kg) solution or an equivalent volume of saline. Cdyn was significantly higher after treatment with L-97-1 compared with untreated controls (p < 0.05 n = 5). Histamine PC30 was significantly higher (p < 0.05; n = 5) after L-97-1 at 24 h compared with histamine PC30 at 24 h after HDM. Adenosine PC30 was significantly higher at 15 min and 6 h after L-97-1 compared with control (p < 0.05; n = 5). L-97-1 showed strong affinity for human A1 ARs in radioligand binding studies and no inhibition toward human phosphodiesterase II, III, IV, and V enzymes. These data suggest that L-97-1 produces a significant reduction of histamine or adenosine-induced hyper-responsiveness and HDM-induced EAR and LAR in allergic rabbits by blocking A1 ARs and may be beneficial as an oral therapy for human asthma.

Binding of bilirubin with albumin-coupled liposomes: implications in the treatment of jaundice

In the present study, we demonstrated the suitability of liposomes as a method of removing plasma bilirubin in hyperbilirubinemic rats. The liposomes have innate tendency to bind with bilirubin through hydrophobic interaction. Among different types of liposomes, the positively charged liposomes were found to have maximum affinity to free bilirubin. However, the entrapment or coupling of serum albumin on the surface of egg phosphatidylcholine liposomes can render a several-fold increase in their bilirubin binding capacity. The proteoliposomes were able to preferentially bind with bilirubin even in the presence of erythrocytes. Interestingly, these liposomes were found to displace bilirubin bound on the surface of erythrocytes as well. The results of the present study further demonstrate that albumin-bearing liposomes were equally effective in removing plasma bilirubin in experimental jaundiced animals. These observations indicate that liposome-mediated selective homing of excess plasma bilirubin to the liver cells (cf. hepatocytes) may help in the development of safer strategy for the treatment of hyperbilirubinemic conditions in the model animals.

Stent-based gene therapy

Delivery of gene therapy to inhibit intimal hyperplasia has been proposed to prevent postangioplasty restenosis. We sought to apply gene therapy by using a stent-based technique. There are several hurdles that must be overcome before gene-stent therapy can be applied successfully in clinical trials. These include increasing the efficiency of gene delivery through atherosclerotic plaque; increasing intramural retention times; preventing the inflammatory reaction that stents coated with biodegradable polymers can elicit; overcoming the risk of systemic gene delivery; and accessing the adventitia via percutaneous approach. We evaluated a gene-stent delivery mechanism based on microporous metal microneedles developed with nanotechnology in an attempt to overcome some of these problems. A novel approach to the transfection of genes by microfabricated technology was evaluated in smooth muscle cells in culture. We demonstrated that microneedles can deliver gene therapy to smooth muscle cells in culture and can produce controlled penetration of the IEL and intima. We conclude that taller microneedles need to be developed to reach the media in diseased human arteries and that this technology has the potential to be incorporated in a stent to deliver gene therapy in atherosclerotic plaque.

Meningococcal infection among pilgrims visiting Madinah Al-Munawarah despite prior A-C vaccination

OBJECTIVE

To study the profile of meningococcal infection among pilgrims despite prior A-C vaccination.

SETTING

King Abdul Aziz Hospital, Madinah Al-Munawarah, Saudi Arabia.

SUBJECTS AND METHODS

Fifteen patients admitted to the hospital during the study period of April 1992 to June 1993 were evaluated prospectively regarding their clinical and laboratory features, culture and antibiotic sensitivity and meningococcal serotypes.

RESULTS

Twelve cases presented as meningitis while 3 cases had meningococcaemia. Most (53.3%) were from Pakistan while rest were from 6 other countries. Clinical and laboratory features at presentation were similar as reported in the literature. In 13 cases where serotyping could be done, most belonged to group A (54%) and C (23%). Antimicrobial sensitivity showed the isolates to be sensitive to most of the antibiotics commonly used to treat this infection. Mortality was 33% with the poorest outcome in patients with W135 infection.

CONCLUSION

This study underscores the need of further studies in Makkah and Madinah, Saudi Arabia to find out the serotypes and immunological factors responsible for meningococcal infection in A-C vaccinated pilgrims so as to explore the possibility of use of polyvalent meningococcal vaccine.

Micromechanical devices for intravascular drug delivery

Microfabrication technology, more commonly applied to the manufacture of integrated circuits, can be used to build devices useful for mechanical delivery of drugs and genes. Microprobes fabricated using silicon micromachining have been used to deliver DNA into cells as an alternative to bombardment and microinjection. This idea can be extended to intravascular stents with integrated microprobes capable of piercing compressed plaque and delivering anti-restenosis therapies into coronary arteries. Preliminary experiments using filleted rabbit arteries have demonstrated transection of the internal elastic lamina. New nonplanar microfabrication technologies are necessary for creating practical devices with cylindrical symmetry; a promising possibility is to use microfabricated structures of anodic metal oxides.