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1.
J Med Microbiol ; 68(8): 1167-1172, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31199227

ABSTRACT

OBJECTIVES: Elizabethkingia meningoseptica is a multi-drug-resistant organism that is associated with high mortality and morbidity in newborn and immunocompromised patients. This study aimed to identify the best antimicrobial therapy for treating this infection. METHODS: A retrospective descriptive study was conducted from 2010 to 2017 in a tertiary paediatric hospital in Singapore. Paediatric patients aged 0 to 18 years old with a positive culture for E. meningoseptica from any sterile site were identified from the hospital laboratory database. The data collected included clinical characteristics, antimicrobial susceptibility and treatment, and clinical outcomes. RESULTS: Thirteen cases were identified in this study. Combination therapy with piperacillin/tazobactam and trimethoprim/sulfamethoxazole or a fluoroquinolone resulted in a cure rate of 81.8  %. The mortality rate was 15.4  % and neurological morbidity in patients with bacteraemia and meningitis remained high (75 %). CONCLUSIONS: Treatment with combination therapy of piperacillin/tazobactam and trimethoprim/sulfamethoxazole or a fluroquinolone was effective in this study, with low mortality rates being observed.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Flavobacteriaceae Infections/drug therapy , Fluoroquinolones/therapeutic use , Piperacillin, Tazobactam Drug Combination/therapeutic use , Trimethoprim, Sulfamethoxazole Drug Combination/therapeutic use , Anti-Bacterial Agents/pharmacology , Child , Child, Preschool , Female , Flavobacteriaceae/drug effects , Flavobacteriaceae/isolation & purification , Flavobacteriaceae Infections/epidemiology , Flavobacteriaceae Infections/microbiology , Fluoroquinolones/pharmacology , Humans , Infant , Infant, Newborn , Male , Microbial Sensitivity Tests , Piperacillin, Tazobactam Drug Combination/pharmacology , Retrospective Studies , Risk Factors , Singapore/epidemiology , Treatment Outcome , Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology
2.
Plant Physiol Biochem ; 110: 118-127, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27622847

ABSTRACT

This report focuses on application of zinc oxide nanoparticles (ZnONPs) carrying phycomolecule ligands as a novel plant growth promoter aimed at increasing the crop productivity. The present investigation examined the effect of ZnONPs on plant growth characteristics, and associated biochemical changes in cotton (Gossypium hirsutum L.) following growth in a range of concentrations (25-200 mg L-l ZnONPs) in combination with 100 mM P in a hydroponic system. Treated plants registered an increase in growth and total biomass by 130.6% and 131%, respectively, over control. Results demonstrated a significant increase in the level of chlorophyll a (141.6%), b (134.7%), carotenoids (138.6%), and total soluble protein contents (179.4%); at the same time, a significant reduction (68%) in the level of malondialdehyde (MDA) in leaves with respect to control. Interestingly, a significant increase in superoxide dismutase (SOD, 264.2%), and peroxidase (POX, 182.8%) enzyme activities followed by a decrease in the catalase (CAT) activity, in response to above treatments. These results suggest that bioengineered ZnONPs interact with meristematic cells triggering biochemical pathways conducive to an accumulation of biomass. Further investigations will map out the mode of action involved in growth promotion.


Subject(s)
Gossypium/drug effects , Metal Nanoparticles/administration & dosage , Phosphorus/pharmacology , Zinc Oxide/pharmacology , Biomass , Carotenoids/metabolism , Catalase/metabolism , Chlorophyll/metabolism , Dose-Response Relationship, Drug , Gossypium/growth & development , Gossypium/metabolism , Hydroponics/methods , Malondialdehyde/metabolism , Meristem/drug effects , Meristem/growth & development , Meristem/metabolism , Metal Nanoparticles/chemistry , Metal Nanoparticles/ultrastructure , Microscopy, Electron, Scanning , Peroxidase/metabolism , Phosphorus/chemistry , Plant Proteins/metabolism , Spectrometry, X-Ray Emission , Spectroscopy, Fourier Transform Infrared , Superoxide Dismutase/metabolism , Surface Properties , X-Ray Diffraction , Zinc Oxide/chemistry
3.
Bone Joint J ; 98-B(3): 420-4, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26920970

ABSTRACT

AIMS: The management of open lower limb fractures in the United Kingdom has evolved over the last ten years with the introduction of major trauma networks (MTNs), the publication of standards of care and the wide acceptance of a combined orthopaedic and plastic surgical approach to management. The aims of this study were to report recent changes in outcome of open tibial fractures following the implementation of these changes. PATIENTS AND METHODS: Data on all patients with an open tibial fracture presenting to a major trauma centre between 2011 and 2012 were collected prospectively. The treatment and outcomes of the 65 Gustilo Anderson Grade III B tibial fractures were compared with historical data from the same unit. RESULTS: The volume of cases, the proportion of patients directly admitted and undergoing first debridement in a major trauma centre all increased. The rate of limb salvage was maintained at 94% and a successful limb reconstruction rate of 98.5% was achieved. The rate of deep bone infection improved to 1.6% (one patient) in the follow-up period. CONCLUSION: The reasons for these improvements are multifactorial, but the major trauma network facilitating early presentation to the major trauma centre, senior orthopaedic and plastic surgical involvement at every stage and proactive microbiological management, may be important factors. TAKE HOME MESSAGE: This study demonstrates that a systemised trauma network combined with evidence based practice can lead to improvements in patient care.


Subject(s)
Fractures, Open/surgery , Practice Guidelines as Topic , Quality Improvement/organization & administration , Tibial Fractures/surgery , Trauma Centers/organization & administration , Adolescent , Adult , Aged , Aged, 80 and over , Delivery of Health Care, Integrated/organization & administration , Female , Fracture Fixation/methods , Fracture Fixation/standards , Humans , London , Male , Middle Aged , Patient Care Team/organization & administration , Plastic Surgery Procedures/methods , Plastic Surgery Procedures/standards , Retrospective Studies , Soft Tissue Injuries/surgery , Surgical Wound Infection/etiology , Trauma Centers/standards , Young Adult
4.
Biomaterials ; 64: 125-135, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26111596

ABSTRACT

D-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), a glycosphingolipid synthesis inhibitor, holds promise for the treatment of atherosclerosis and cardiac hypertrophy but rapid in vivo clearance has severely hindered translation to the clinic. To overcome this impediment, we used a materials-based delivery strategy wherein D-PDMP was encapsulated within a biodegradable polymer composed of poly ethylene glycol (PEG) and sebacic acid (SA). PEG-SA was formulated into nanoparticles that were doped with (125)I-labeled PEG to allow in vivo bio-distribution and release kinetics of D-PDMP to be determined by using γ-scintigraphy and subsequently, by mass spectrometry. Polymer-encapsulation increased the residence time of D-PDMP in the body of a treated mouse from less than one hour to at least four hours (and up to 48 h or longer). This substantially increased in vivo longevity provided by polymer encapsulation resulted in an order of magnitude gain in efficacy for interfering with atherosclerosis and cardiac hypertrophy in apoE-/- mice fed a high fat and high cholesterol (HFHC) diet. These results establish that D-PDMP encapsulated in a biodegradable polymer provides a superior mode of delivery compared to unconjugated D-PDMP by way of increased gastrointestinal absorption and increased residence time thus providing this otherwise rapidly cleared compound with therapeutic relevance in interfering with atherosclerosis, cardiac hypertrophy, and probably other diseases associated with the deleterious effects of abnormally high glycosphingolipid biosynthesis or deficient catabolism.


Subject(s)
Atherosclerosis/drug therapy , Cardiomegaly/drug therapy , Morpholines/administration & dosage , Animals , Aortic Diseases/blood , Aortic Diseases/drug therapy , Aortic Diseases/prevention & control , Apolipoproteins E/deficiency , Atherosclerosis/blood , Atherosclerosis/prevention & control , Capsules , Cardiomegaly/blood , Cholesterol, Dietary/toxicity , Decanoic Acids , Delayed-Action Preparations , Dicarboxylic Acids , Diet, Atherogenic , Drug Evaluation, Preclinical , Heart Ventricles/pathology , Inactivation, Metabolic , Iodine Radioisotopes/analysis , Lipids/blood , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Molecular Structure , Morpholines/pharmacokinetics , Nanoparticles/administration & dosage , Polyethylene Glycols , Tissue Distribution , Vascular Stiffness/drug effects
5.
Plant Physiol Biochem ; 51: 90-101, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22153244

ABSTRACT

The objective of the present study was to examine the role of SOS pathway in salinity stress tolerance in Brassica spp. An experiment was conducted in pot culture with 4 Brassica genotypes, i.e., CS 52 and CS 54, Varuna and T 9 subjected to two levels of salinity treatments along with a control, viz., 1.65 (S(0)), 4.50 (S(1)) and 6.76 (S(2)) dS m(-1). Salinity treatment significantly decreased relative water content (RWC), membrane stability index (MSI) and chlorophyll (Chl) content in leaves and potassium (K) content in leaf, stem and root of all the genotypes. The decline in RWC, MSI, Chl and K content was significantly less in CS 52 and CS 54 as compared to Varuna and T 9. In contrast, the sodium (Na) content increased under salinity stress in all the plant parts in all the genotypes, however, the increase was less in CS 52 and CS 54, which also showed higher K/Na ratio, and thus more favourable cellular environment. Gene expression studies revealed the existence of a more efficient salt overly sensitive pathway composed of SOS1, SOS2, SOS3 and vacuolar Na(+)/H(+) antiporter in CS 52 and CS 54 compared to Varuna and T 9. Sequence analyses of partial cDNAs showed the conserved nature of these genes, and their intra and intergenic relatedness. It is thus concluded that existence of an efficient SOS pathway, resulting in higher K/Na ratio, could be one of the major factor determining salinity stress tolerance of Brassica juncea genotypes CS 52 and CS 54.


Subject(s)
Brassica/genetics , Salt-Tolerant Plants/genetics , Sodium Chloride/pharmacology , Stress, Physiological , Amino Acid Sequence , Brassica/drug effects , Brassica/metabolism , Brassica/physiology , Calcium Chloride/pharmacology , Cell Membrane/metabolism , Chlorophyll/metabolism , DNA, Complementary/genetics , Gene Expression Regulation, Plant , Genes, Plant , Genotype , Molecular Sequence Data , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Leaves/physiology , Plant Roots/genetics , Plant Roots/metabolism , Plant Roots/physiology , Plant Stems/metabolism , Plant Stems/physiology , Potassium/metabolism , Salt-Tolerant Plants/drug effects , Salt-Tolerant Plants/metabolism , Salt-Tolerant Plants/physiology , Sequence Alignment , Sodium/metabolism , Sodium-Hydrogen Exchangers/metabolism , Water/metabolism
6.
Bone ; 46(3): 655-9, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19853678

ABSTRACT

INTRODUCTION: Osteoporosis is a major health problem for postmenopausal women. Adjuvant hormonal therapy with aromatase inhibitors (AIs) in postmenopausal breast cancer patients further worsens bone loss. Bisphosphonates are able to prevent AI-induced bone loss, but limited data exists on their effect on bone structure. Our objectives were to (1) examine the impact of AIs and no-AIs on hip structural geometry (HSA) of chemotherapy-induced postmenopausal women, and (2) determine if oral bisphosphonates could affect these changes. METHODS: This is a sub-analysis of a 2-year double-blind randomized trial of 67 women with nonmetastatic breast cancer, newly postmenopausal following chemotherapy (up to 8 years), who were randomized to risedronate, 35 mg once weekly (RIS) and placebo (PBO). Many women changed their cancer therapy from a no-AI to an AI during the trial. Outcomes were changes in Beck's HSA-derived BMD and structural parameters. RESULTS: Eighteen women did not receive adjuvant hormone therapy, while 41 women received other therapy and 8 received AIs at baseline distributed similarly between RIS and PBO. Women on AIs and PBO were found to have the lowest BMD and indices. RIS improved BMD and several HSA indices at the intertrochanteric site in women regardless of their hormonal therapy, but most improvement was observed in women who were not on AIs (all p< or =0.05 except buckling ratio). Changes at the narrow neck and femoral shaft were similar. CONCLUSION: The use of AIs appears to lead to lower HSA-derived BMD and hip structural indices as compared to women on no or non-AI therapy in chemotherapy-induced postmenopausal breast cancer patients. Preventive therapy with once weekly oral risedronate maintains structural, skeletal integrity independently of the use of or type of adjuvant therapy.


Subject(s)
Antineoplastic Agents, Hormonal/adverse effects , Aromatase Inhibitors/adverse effects , Etidronic Acid/analogs & derivatives , Hip Joint/drug effects , Osteoporosis, Postmenopausal/diagnostic imaging , Osteoporosis, Postmenopausal/prevention & control , Bone Density/drug effects , Bone Density/physiology , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/drug therapy , Double-Blind Method , Etidronic Acid/pharmacology , Etidronic Acid/therapeutic use , Female , Follow-Up Studies , Hip Joint/diagnostic imaging , Humans , Middle Aged , Osteoporosis, Postmenopausal/chemically induced , Postmenopause/drug effects , Radiography , Risedronic Acid
7.
Indian J Exp Biol ; 46(10): 690-7, 2008 Oct.
Article in English | MEDLINE | ID: mdl-19024166

ABSTRACT

Chronic arsenic exposure causes skin diseases, gastrointestinal and neurological disorders, diabetes and cancer in various organs. Oxidative stress associated with arsenic exposure cause genetic instabilities and may initiate carcinogenesis. Phytochemicals present in vegetables, fruits, spices, tea, and medicinal plants, have shown to suppress experimental carcinogenesis in various organs. The aim of the present study was to elucidate the protective effect of some of the phytochemicals against the arsenite induced DNA damage in normal mammalian V79 cells. Comet assay was used for assessment of DNA damage and 2', 7'-dichlorofluorescein dihydroacetate for estimation of ROS generated by arsenite. The effect of the phytochemicals was observed during simultaneous treatment with arsenic, before arsenite exposure and during repair experiments. Of all the phytochemicals tested against arsenic, curcumin gave better protection during simultaneous treatment and resveratrol during pre treatment, which was evident both from comet assay and ROS generation experiments. During pre treatment a longer duration of treatment with lower dose of phytochemicals proved fruitful in reducing the genotoxicity. During repair experiments the phytochemicals enhanced recovery of DNA damage and ellagic acid gave promising results. The results indicated that natural phytochemicals may have the efficacy in reducing arsenic induced genotoxicity, in scavenging ROS and in enhancing the process of DNA repair in V79 cells.


Subject(s)
Arsenites/antagonists & inhibitors , Arsenites/toxicity , Diet , Mutagens/toxicity , Animals , Capsaicin/pharmacology , Cell Line , Comet Assay , Cricetinae , Cricetulus , Curcumin/pharmacology , DNA Damage , Ellagic Acid/pharmacology , Flavonoids/pharmacology , Reactive Oxygen Species/metabolism , Resveratrol , Stilbenes/pharmacology
8.
Article in English | MEDLINE | ID: mdl-16611159

ABSTRACT

Although caffeine is not carcinogenic, its hydrolysed product, caffeidine causes human cancer, possibly through endogenous nitrosation to form mononitroso caffeidine (MNC). MNC undergoes enzymatic demethylation and reacts with cellular nucleophiles, notably DNA, via the formation of a putative imidazole diazonium ion. Its interaction with proteins has not been reported. The present work is based on the hypothesis that some active metabolites of MNC covalently interact with cellular DNA and/or proteins to initiate carcinogenesis. We report here the synthesis of a possible reactive metabolite of MNC, viz., N, 1-methyl-4(N-methyl-N-nitrosamino)-imidazole-5-carboxylic acid (MNIC). Its structure has been determined by uv, ir, nmr and mass spectral analyses and its interaction with egg albumin and human serum protein has been examined by uv and CD spectroscopy. We concluded that metabolic activation of MNC occurs through the formation of MNIC. Avoiding consumption of salted tea or coffee that prevents the intake of caffeidine will possibly eliminate the risk of MNC carcinogenicity.


Subject(s)
Anticarcinogenic Agents , Caffeine/analogs & derivatives , Amino Acids/chemistry , Animals , Biotransformation , Blood Proteins/chemistry , Caffeine/pharmacokinetics , Caffeine/pharmacology , Carcinogens/toxicity , Chromatography, High Pressure Liquid , Circular Dichroism , Coffee/chemistry , Humans , Magnetic Resonance Spectroscopy , Male , Mass Spectrometry , Mice , Nitroimidazoles/antagonists & inhibitors , Nitroimidazoles/toxicity , Spectrophotometry, Infrared , Spectrophotometry, Ultraviolet , Tea/chemistry
9.
Cancer Lett ; 230(1): 111-21, 2005 Dec 08.
Article in English | MEDLINE | ID: mdl-16253767

ABSTRACT

Treatment of human leukemic cell lines HL-60 and K-562 with extracts of green and black tea and their polyphenols epigallocatechin gallate and theaflavins, respectively, showed a dose dependent inhibition of growth as a result of cytotoxicity and suppression of cell proliferation. Based on the IC50 values obtained from cytotoxicity data it was clearly evident that black tea was as efficient as green tea. Analysis of polyphenol contents of tea extracts revealed that not only epigallocatechin gallate, which is a predominant polyphenol of green tea, but also theaflavin that is abundantly present in black tea affords significant chemotherapeutic action by imparting cytotoxicity to human leukemic cells. Electrophoretic analysis of fragmented DNA from treated cells displayed characteristic ladder pattern. Flow cytometric analysis revealed the dose dependent increase in sub-G1 peak. These criteria confirmed that cytotoxic activity of green and black tea was due to induction of apoptosis. Such induction was found to be mediated through activation of caspases 3 and 8, particularly caspase 3 and by altering apoptosis related genes as evident by down-regulation of Bcl-2 and up-regulation of Bax proteins.


Subject(s)
Antioxidants/pharmacology , Apoptosis/drug effects , Biflavonoids/pharmacology , Catechin/pharmacology , Tea/chemistry , Caspase 3 , Caspase 8 , Caspases/drug effects , Caspases/metabolism , Down-Regulation , Flavonoids/analysis , Flavonoids/pharmacology , Flow Cytometry , Genes, bcl-2 , HL-60 Cells , Humans , Phenols/analysis , Phenols/pharmacology , Polyphenols , bcl-2-Associated X Protein
10.
Phytother Res ; 18(8): 595-600, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15476314

ABSTRACT

Tiliacora racemosa and Semecarpus anacardium, the two plants frequently used in Ayurvedic medicine for the treatment of cancerous diseases, have been selected to examine their action in four human tumour cell lines: acute myeloblastic leukaemia (HL-60), chronic myelogenic leukaemia (K-562), breast adenocarcinoma (MCF-7) and cervical epithelial carcinoma (HeLa). In cells grown in appropriate media the ethanol extract of T. racemosa root, the total alkaloids isolated from this organ and S. anacardium nut oil prepared according to the Ayurvedic principle were found to have cytotoxic activity. The alkaloid fraction from T. racemosa had maximum cytotoxicity and was effective against all four cell lines. S. anacardium oil was cytotoxic only in leukaemic cells. These herbal preparations were not cytotoxic towards normal human lymphocytes, suggesting their action is specific for tumour cells. On microscopic examination the cells treated with these agents exhibited characteristic morphological features of apoptosis, such as cell shrinkage, and the formation of apoptotic bodies. Fluorescent staining with propidium iodide revealed distinct chromatin condensation and nuclear fragmentation. The apoptotic index paralleled the cytotoxic parameters, and fragmented DNA extracted free of genomic DNA from treated cells displayed a typical ladder pattern on gel electrophoresis. Apoptosis induced by alkaloids and phenolics, the active principles present in T. racemosa and S. anacardium, respectively, was found to be mediated by the activation of caspases.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Phytotherapy , Plant Extracts/pharmacology , Plant Oils/pharmacology , Plants, Medicinal , Semecarpus , Antineoplastic Agents, Phytogenic/administration & dosage , Antineoplastic Agents, Phytogenic/therapeutic use , Apoptosis/drug effects , Cell Line, Tumor/drug effects , DNA Fragmentation/drug effects , Dose-Response Relationship, Drug , Fruit , HL-60 Cells/drug effects , HeLa Cells/drug effects , Humans , K562 Cells/drug effects , Medicine, Ayurvedic , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Plant Oils/administration & dosage , Plant Oils/therapeutic use , Plant Roots
11.
Asian Pac J Cancer Prev ; 4(3): 233-7, 2003.
Article in English | MEDLINE | ID: mdl-14507244

ABSTRACT

Arsenic, a naturally ocurring chemical element, is considered hazardous to human health. Inorganic arsenic compounds were found to induce cytotoxicity in Chinese hamster V-79 cells in culture. The arsenite form was more toxic than arsenate. Extracts of green and two varieties of black tea, as well as their principal polyphenols, (-)-epigallocatechingallate and theaflavin, efficiently counteracted the cytotoxic effects of arsenic compounds. On the basis of the amount of tea extract that afforded 50% protection to the cells from arsenic induced cytotoxicity, black tea was found to be as effective as green tea. The protective effect was attributable to the contents of not only (-)-epigallocatechingallate but also of theaflavin, the latter being a predominant polyphenol present in black tea.


Subject(s)
Arsenic/antagonists & inhibitors , Cytotoxins/antagonists & inhibitors , Tea , Animals , Arsenic/toxicity , Cell Line, Tumor , Chemoprevention , Cricetinae , Cricetulus , Male
12.
J Appl Toxicol ; 21(6): 495-9, 2001.
Article in English | MEDLINE | ID: mdl-11746197

ABSTRACT

Recently we have shown that cyanide poisoning by the oral (p.o.) route could be antagonized significantly by pretreatment or simultaneous treatment of alpha-ketoglutarate (alpha-KG), administered p.o. in rodents. The protective effect of alpha-KG was dose dependent (0.125-2.0 g kg(-1)) and the effect was significant at a dose above 1.0 g kg(-1). In order to establish the safety of alpha-KG, various haematological, biochemical and histological parameters were studied following p.o. administration of 2.0 g kg(-1)alpha-KG in female rats, and various physiological parameters were studied following p.o. administration of 2.0 or 4.0 g kg(-1)alpha-KG in anaesthetized male rats. The p.o. LD(50) of alpha-KG in male and female rats was >5.0 g kg(-1) and no toxic signs were observed in the surviving animals. Except for an increase in plasma alkaline phosphatase and urea levels after 1 h and a decrease in inorganic phosphorus levels after 7 days of treatment, no significant change in haematology, biochemistry or histology of the vital organs were observed. Mean arterial pressure and neuromuscular transmission were decreased at 4.0 g kg(-1)alpha-KG but other physiological variables such as heart rate, respiratory rate, rectal temperature, left ventricular pressure (systolic), arterial pressure (systolic) and arterial pressure (diastolic) were not altered. The changes observed at 4.0 g kg(-1)alpha-KG are unlikely to be of toxicological concern. The results indicate that alpha-KG at 2.0 g kg(-1) (p.o.)-a dose offering maximum antidotal efficacy-is non-toxic and therefore can be considered suitable for cyanide poisoning.


Subject(s)
Antidotes/adverse effects , Antidotes/pharmacology , Ketoglutaric Acids/adverse effects , Ketoglutaric Acids/pharmacology , Radiation-Protective Agents/adverse effects , Radiation-Protective Agents/pharmacology , Administration, Oral , Alkaline Phosphatase/blood , Animals , Dose-Response Relationship, Drug , Female , Lethal Dose 50 , Male , Phosphorus/blood , Poisoning/drug therapy , Poisons/adverse effects , Potassium Cyanide/poisoning , Rats , Rats, Wistar , Urea/blood
13.
J Cell Biochem ; 81(2): 357-67, 2001 Mar 26.
Article in English | MEDLINE | ID: mdl-11241675

ABSTRACT

The active metabolite of vitamin D, 1 alpha,25-dihydroxyvitamin D(3)[1,25(OH)(2)D(3)] has been receiving increasing attention and has come to the forefront of cancer chemoprevention research as being a regulator of cellular growth, differentiation and death. In the present study, attempts have been made to investigate the in vivo chemopreventive effect of 1,25(OH)(2)D(3) in two-stage rat liver carcinogenesis. Hepatocarcinogenesis was initiated with a single intraperitoneal injection of diethylnitrosamine [DEN] (200 mg/kg b. wt.) at week 4. After a brief recovery period of 2 weeks, all the DEN-treated rats were given phenobarbital (0.05%) in the basal diet and continued thereafter till the completion of the experiment. The results of our experiment showed that the rats which received 1,25(OH)(2)D(3) for 14 weeks (0.3 microg/100 microL propylene glycol, per os, twice a week), starting the treatment 4 weeks prior to DEN injection, exhibited maximum protective effect in maintaining the normal cellular architecture of the hepatocytes than the group of rats which received this micronutrient for only 9 weeks. Moreover, continuous supplementation of 1,25(OH)(2)D(3) maintains the concentration of hepatic microsomal cytochrome P-450 like that of normal vehicle control. Thus, long-term supplementation of 1,25(OH)(2)D(3) significantly (P < 0.001) inhibits hepatic cytosolic lipid peroxidation, thereby protecting the cell membranes from free-radical mediated damage. These results suggest that 1,25(OH)(2)D(3) is useful in the inhibition of rat liver carcinogenesis.


Subject(s)
Calcitriol/pharmacology , Diethylnitrosamine/pharmacology , Liver Neoplasms/chemically induced , Liver Neoplasms/prevention & control , Liver/drug effects , Liver/ultrastructure , Phenobarbital/pharmacology , Animals , Cytochrome P-450 Enzyme System/biosynthesis , Dose-Response Relationship, Drug , Endoplasmic Reticulum/metabolism , Liver/pathology , Liver Neoplasms/pathology , Male , Microscopy, Electron , Rats , Rats, Sprague-Dawley , Time Factors
14.
Biomed Environ Sci ; 13(4): 293-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11351863

ABSTRACT

Kombucha tea (KT) is a popular health beverage and is used as an alternative therapy. KT is prepared by placing the kombucha culture in solution of tea and sugar and allowing to ferment. The inoculum is a fungus consisting of symbiotic colony of yeast and bacteria. KT is consumed in several countries and is believed to have prophylactic and therapeutic benefits in a wide variety of ailments, viz., intestinal disorders, arthritis, ageing and stimulation of immunological system. Though KT is used in several parts of the world its beneficial effects and adverse effects have not been scientifically evaluated. Since there are no animal toxicological data on KT, subacute oral toxicity study was carried out. Five groups of rats were maintained: (a) control group given tap water orally, (b) KT given 2 ml/kg orally, (c) plain tea (PT) given 2 ml/kg orally, (d) KT given in drinking water, 1% (v/v) and (e) PT given in drinking water, 1% (v/v). The rats were given this treatment daily for a period of 90 days. Weekly records of weight, feed intake, water intake and general behaviour were monitored. There was no significant difference in the growth of the animals as evidenced by the progressive body weight change. The organ to body weight ratio and histological evaluation did not show any toxic signs. The haematological and biochemical variables were within the clinical limits. The study indicates that rats fed KT for 90 days showed no toxic effects.


Subject(s)
Bacteria , Beverages/toxicity , Complementary Therapies , Yeasts , Administration, Oral , Animals , Blood Glucose/analysis , Blood Urea Nitrogen , Female , Fermentation , Liver Function Tests , No-Observed-Adverse-Effect Level , Rats , Rats, Wistar
15.
Indian J Biochem Biophys ; 36(6): 442-8, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10844999

ABSTRACT

The activity of thymidylate synthase (TS) purified in our laboratory from Lactobacillus leichmannii was inhibited by pergularinine (PGL) and tylophorinidine (TPD) and deoxytubulosine (DTB) isolated from the Indian medicinal plants Pergularia pallida and Alangium lamarckii respectively. Cytotoxicity studies showed that cell growth of L. leichmannii was inhibited (IC50 = 40-45 microM) by all the three alkaloids, the concentrations > 80-90 microM resulting in complete loss of the enzyme activity. Ki values of the enzyme calculated from Lineweaver-Burk and Dixon plots for PGL, TPD and DTB were 10 x 10(-6) M, 9 x 10(-6) M and 7 x 10(-6) M respectively. These are typed as 'non-competitive' inhibitors of TS. All the three alkaloids inhibited (IC50 = 50 microM) the elevated TS activity of leukocytes in cancer patients with clinically diagnosed chronic myelocytic leukemia (n = 10), acute lymphocytic leukemia (n = 8) and metastatic solid tumours (n = 3).


Subject(s)
Alkaloids , Emetine/analogs & derivatives , Enzyme Inhibitors/pharmacology , Isoquinolines/pharmacology , Thymidylate Synthase/antagonists & inhibitors , Emetine/pharmacology , Humans , Neoplasms/blood , Neoplasms/enzymology
16.
Anticancer Drugs ; 9(8): 727-32, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9823431

ABSTRACT

Precursor 2'-deoxythymidine 5'-monophosphate for DNA biosynthesis is supplied by thymidylate synthase (TS) (EC 2.1.1.45) through a de novo pathway and the enzyme levels are elevated in malignancy. TS is therefore a key target for cancer chemotherapy. Human leukocyte TS levels in patients with chronic myeloblastic leukemia (CML) and acute lymphoblastic leukemia (ALL) are highly elevated (66- and 33-fold, respectively) compared to the low baseline activity of normal healthy controls. Preliminary screening tests for the antitumor activity of the beta-carboline-benzoquinolizidine alkaloid deoxytubulosine (DTB) (isolated from the Indian medicinal plant Alanguim lamarckii) were performed employing in vitro inhibition studies on the leukemic leukocyte TS as the probe enzyme. Enzyme activity of the leukemic leukocytes was potently inhibited by DTB (IC50 = 50 microM) in both CML and ALL. The emetine alkaloid DTB was assessed for its biochemical and biological evaluation for the first time as a potential antileukemic agent.


Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukocytes/enzymology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Quinolizines/pharmacology , Thymidylate Synthase/antagonists & inhibitors , Tubercidin/pharmacology , Adolescent , Adult , Antineoplastic Agents/pharmacology , Child , Child, Preschool , Female , Humans , Leukocyte Count , Leukocytes/drug effects , Male , Middle Aged , Thymidylate Synthase/metabolism
17.
Cancer Lett ; 128(2): 183-8, 1998 Jun 19.
Article in English | MEDLINE | ID: mdl-9683281

ABSTRACT

Thymidylate synthase (TS) (EC 2.1.1.45) provides precursors for DNA biosynthesis through a de novo pathway and is a key target enzyme for cancer chemotherapy. TS levels of human leukemic leukocytes from patients with chronic myelocytic leukemia (CML) and acute lymphocytic leukemia (ALL) were observed to be highly elevated (66- and 33-fold for CML and ALL, respectively) compared to the usual low level of basal activity in normal healthy controls. In vitro inhibition studies on the human leukemic leukocyte TS with the phenanthroindolizidine alkaloids pergularinine (PGL) and tylophorinidine (TPD) (isolated from the Indian medicinal herb Pergularia pallida) were conducted for the preliminary screening tests for their antitumor activity. The leukemic leukocyte enzyme activity was potently inhibited by PGL and TPD (IC50 = 50 microM) in both types of leukemias. These alkaloids were assessed for biological evaluation for the first time as potential antileukemic agents.


Subject(s)
Alkaloids , Antineoplastic Agents, Phytogenic/pharmacology , Enzyme Inhibitors/pharmacology , Isoquinolines/pharmacology , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology , Leukocytes/enzymology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/enzymology , Thymidylate Synthase/antagonists & inhibitors , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukocytes/drug effects , Male , Middle Aged , Precursor Cell Lymphoblastic Leukemia-Lymphoma/blood , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Thymidylate Synthase/blood
18.
J Biochem Mol Toxicol ; 12(3): 167-73, 1998.
Article in English | MEDLINE | ID: mdl-9522276

ABSTRACT

Employing thymidylate synthase (TS) (5, 10-CH2-H4PteGlu: dUMP C-methyltransferase, EC 2.1.1.45), a key target enzyme in chemotherapy, the biological activity of the beta-carboline-benzoquinolizidine alkaloid deoxytubulosine (DTB) isolated from the Indian medicinal plant Alangium lamarckii has been evaluated and assessed for the first time. The TS employed in the present studies was purified from Lactobacillus leichmannii. The DTB was demonstrated to exhibit potent cytotoxicity and inhibited the cell growth of L. leichmannii, and DTB potently inhibited TS activity (IC50 = 40 microM). The DTB concentrations > 80 microM resulted in a total loss of the TS activity, thus suggesting that the beta-carboline-benzoquinolizidine alkaloid is a promising potential antitumor agent. The DTB binding to TS appears to be irreversible and tight through a possible covalent linkage. Although DTB strongly binds to DNA, it is not known whether DTB binds to RNA associated with TS. Inhibition kinetics showed that TS has a Ki value of 7 x 10(-6) M for DTB and that the inhibition is a simple linear "noncompetitive" type.


Subject(s)
Emetine/analogs & derivatives , Emetine/pharmacology , Growth Inhibitors/pharmacology , Lactobacillus/enzymology , Plants, Medicinal/chemistry , Quinolizines/pharmacology , Thymidylate Synthase/antagonists & inhibitors , Thymidylate Synthase/metabolism , Tubercidin/pharmacology , Cell Division/drug effects , Emetine/toxicity , Kinetics , Lactobacillus/drug effects , Lactobacillus/growth & development , Models, Molecular , Protein Binding/drug effects , Quinolizines/toxicity , Tubercidin/toxicity
19.
Chem Biol Interact ; 106(3): 201-12, 1997 Oct 24.
Article in English | MEDLINE | ID: mdl-9413547

ABSTRACT

Biological activity of the phenanthroindolizidine alkaloids pergularinine (PGL) and tylophorinidine (TPD) isolated from the Indian medicinal herb Pergularia pallida has been evaluated and assessed for the first time employing thymidylate synthase (TS) (5,10-CH2H4 PteGlu: dUMP-C-methyltransferase, EC 2.1.1.45), a key target enzyme in cancer chemotherapy. TS used in the present investigations was purified from Lactobacillus leichmannii. Toxicity studies showed that PGL and TPD were potently toxic and inhibited growth of L.leichmannii cells. Both PGL and TPD significantly inhibited TS activity (IC50 = 40 and 45 microM, respectively). PGL concentrations > 80 microM and TPD concentrations > 90 microM resulted in a complete loss of the TS activity, thus suggesting that both these phenanthroindolizidine alkaloids are promising potential antitumor agents. Our results show that the alkaloid-binding to TS is irreversibly tight through a probable covalent linkage. Inhibition kinetics reveal that the enzyme has Ki values of 10 x 10(-6) and 9 x 10(-6) M for PGL and TPD, respectively and that the inhibition in both the cases is a simple linear 'noncompetitive' type.


Subject(s)
Alkaloids , Antineoplastic Agents, Phytogenic/pharmacology , Isoquinolines/pharmacology , Lactobacillus/drug effects , Thymidylate Synthase/antagonists & inhibitors , Antineoplastic Agents, Phytogenic/chemistry , Cell Division/drug effects , Cell Survival , Dose-Response Relationship, Drug , Isoquinolines/chemistry , Lactobacillus/enzymology , Thymidylate Synthase/isolation & purification
20.
Indian J Med Res ; 105: 131-5, 1997 Mar.
Article in English | MEDLINE | ID: mdl-9119419

ABSTRACT

Effects of paracetamol treatment in vivo to young-adult (2-3 months) and old (22-24 months) rats at subtoxic (375 mg/kg) and toxic (750 mg/kg) doses on kidney mitochondrial energy metabolism were examined. Administration of paracetamol (both doses) to young-adult animals did not, in general, affect the respiratory functions of kidney mitochondria. On the other hand, treatment of toxic doses to aged animals resulted in decrease in the state 3 respiration rates with glutamate, pyruvate + malate and succinate as substrates. Succinoxidase activity was also impaired in this experimental group. With subtoxic doses, state 3 respiration rate was decreased only with pyruvate + malate as substrate. Results indicate that the in vivo administration of paracetamol impaired kidney mitochondrial energy metabolism in aged animals.


Subject(s)
Acetaminophen/toxicity , Analgesics, Non-Narcotic/toxicity , Kidney/drug effects , Mitochondria/drug effects , Oxygen Consumption/drug effects , Aging/physiology , Animals , Drug Evaluation, Preclinical , Kidney/ultrastructure , Male , Rats , Rats, Wistar
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