Primary middle ear tuberculosis mimicking cholesteatoma.

Tuberculous granuloma in the middle ear is an unusual entity. Herein, we report a case with short presentation of otitis media with mastoid abscess but with a CT scan showing widespread bone destruction. The cause was determined to be middle ear tuberculosis. Awareness of this entity is important, as it may cause a delay in referral to an otorhinolaryngology specialist and, subsequently, a delay in initiating treatment. Therefore, it should be considered in the differential diagnosis, especially when the usual treatment fails to produce the desired result.

The efficacy of intratympanic steroid injection for the treatment of idiopathic sudden sensorineural hearing loss.

OBJECTIVE: A systemic steroid is known to have a potential to recover hearing after idiopathic sudden sensorineural hearing loss (ISSHL). However, lately many centres have introduced the use of intratympanic (IT) steroid therapy as an option. We reviewed our experience in the treatment of patients with ISSHL looking at the overall success of using systemic steroid, IT steroid injections as salvage therapy and primary IT steroid injection. METHODS: A retrospective study was conducted on 20 patients who had suffered from ISSHL from January 1, 2012, to December 31, 2017. ISSHL is defined as a rapid decline in hearing over three days or less affecting three or more frequencies by 30dB or greater. Comparison between the mode of steroid therapies and improvement in patients was done. At least 15dB improvement in pure tone audiogram (PTA) was considered as successful therapeutic intervention. RESULTS: Twenty male and female patients who fit the inclusion and exclusion criteria were included. The mean age of the patients was 41.4 years with a range from 13 to 72 years. Ninety percent patients presented with unilateral ISSHL involvement. Eight ears of patients who received systemic steroid therapy alone had improved hearings (75%). Out of seven ears from six patients who received salvage therapy, four ears (57.1 %) had improvement in PTA. Seven ears showed improvement in PTA from a total of eight patients who primarily received IT injections. CONCLUSIONS: IT steroid therapy promises a favourable outcome in the improvement of the hearing, as compared to systemic steroid administration. Its usage is recommended not only for salvage therapy but should be used as primary treatment especially in those with co- morbidities.

QTL Mapping and Heterosis Analysis for Fiber Quality Traits Across Multiple Genetic Populations and Environments in Upland Cotton.

An "immortalized F2" (IF2) population and two reciprocal backcross (HSBCF1 and MARBCF1) populations were constructed to investigate the genetic bases of fiber quality traits in upland cotton across four different environments. A relatively high level of heterosis for micronaire (MIC) in IF2 population as well as fiber length (FL) and MIC in MARBCF1 population was observed. A total of 167 quantitative trait loci (QTLs) were detected in the three related experimental populations and their corresponding midparental heterosis (MPH) datasets using the composite interval mapping (CIM) approach. An analysis of genetic effects of QTLs detected in different populations and their MPH datasets showed 16 (24.24%) QTLs of partial dominance, and 46 (69.70%) QTLs of overdominance were identified in an IF2 population; 89 (62.68%) additive QTLs, three (2.11%) partial dominant QTLs, and 49 (34.51%) over-dominant QTLs were detected in two BCF1 populations. Multi-environment analysis showed 48 and 56 main-QTLs (m-QTLs) and 132 and 182 epistasis-QTLs (e-QTLs), by inclusive composite interval mapping (ICIM) in IF2 and two BCF1 populations, respectively. Phenotypic variance explained by e-QTLs, except for MARBCF1 population, was higher than that by m-QTLs. Thus, the overdominant, partial dominant, and epistasis effects were the main causes of heterosis in the IF2 population, whereas the additive, overdominant, and epistasis effects were the primary genetic basis of heterosis in the two BCF1 populations. Altogether, additive effect, partial dominance, overdominance, and epistasis contributed to fiber quality heterosis in upland cotton, but overdominance and epistasis were the most important factors.

Glomus tympanicum.

Glomus tympanicum is a tumour classified under the group glomus tumours, and is also known as paragangliomas. It is thought to commonly occur in women in the fifth to sixth decades of life. Here, we report a case of a 77-year-old lady with multiple co-morbids and a diagnosis of glomus tympanicum presenting to us. Her symptoms included pulsatile tinnitus, and reduced hearing, and the management of the case was done with consideration for her underlying multiple co-morbidities. This paper also describes the best modality of treatment for this patient with regard to her background history. The treatment goal was to improve her quality of life and control the disease.

Relapse of B-cell acute lymphoblastic leukaemia presenting as right aural polyp with facial and mandibular nerves palsy.

A patient presenting with an ear polyp is a common finding in otorhinolaryngology practice. The common causes include chronic otitis media and cholesteatoma. We report an adult female patient with a history of acute leukaemia presenting with chronic otitis media symptoms and right ear polyp. She was subsequently diagnosed as relapse of B-cell acute lymphoblastic leukaemia based on histopathological examination. The presentation may be similar to an inflammatory pathology of the middle ear, making it misleading.

Drinking Water Quality Status and Contamination in Pakistan.

Due to alarming increase in population and rapid industrialization, drinking water quality is being deteriorated day by day in Pakistan. This review sums up the outcomes of various research studies conducted for drinking water quality status of different areas of Pakistan by taking into account the physicochemical properties of drinking water as well as the presence of various pathogenic microorganisms. About 20% of the whole population of Pakistan has access to safe drinking water. The remaining 80% of population is forced to use unsafe drinking water due to the scarcity of safe and healthy drinking water sources. The primary source of contamination is sewerage (fecal) which is extensively discharged into drinking water system supplies. Secondary source of pollution is the disposal of toxic chemicals from industrial effluents, pesticides, and fertilizers from agriculture sources into the water bodies. Anthropogenic activities cause waterborne diseases that constitute about 80% of all diseases and are responsible for 33% of deaths. This review highlights the drinking water quality, contamination sources, sanitation situation, and effects of unsafe drinking water on humans. There is immediate need to take protective measures and treatment technologies to overcome unhygienic condition of drinking water supplies in different areas of Pakistan.

Seed priming by sodium nitroprusside improves salt tolerance in wheat (Triticum aestivum L.) by enhancing physiological and biochemical parameters.

The germination, seedling vigor, crop establishment and yield of agronomically important crops is negatively affected by soil salinity. The current study aimed to investigate the ability of exogenous fertigation by sodium nitroprusside (SNP) to induce salt tolerance in four high yielding wheat cultivars (Sahar-06, Punjab-11, Millat-11 and Galaxy-13) that differ in their response to salt stress in terms of biomass production, oxidative defense mechanisms and grain yield. Three levels of SNP (0, 0.1 and 0.2 mM) were used for seed soaking. During soaking the seeds were kept in the dark. After soaking for 12 h the seeds were air-dried for 5 h before sowing. Salinity caused a significant reduction in biomass and grain yield, while it increased proline (Pro), ascorbic acid (AsA), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. Cultivar Sahar-06 and Galaxy-13 were found more tolerant to salinity based on shoot length root fresh and dry wights, 100 grain weight, decreased MDA and H2O2 accumulation, phenolic and ascorbic acid (AsA) contents, accumulation of proline, activities of SOD, POD and CAT as compared to the other cultivars. Seed priming with SNP was effective in reducing the adverse effects of salt stress induced oxidative stress on plant biomass and grain yield in all the studied wheat cultivars, but maximum amelioration of salt stress tolerance by SNP treatment was found in cv. Sahar-06. The increased salt tolerance in wheat plants by SNP seed priming might be due to the role of NO in improving seed vigor and germination and early establishment of seedlings with better growth. 0.1 mM SNP was found the most effective in improving salt tolerance, as compared to other SNP concentations. Exogenous SNP fertigation increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and the contents of AsA, Pro and total phenolics content (TPC) in the salt stressed wheat plants. Our data indicate that SNP-priming induced salt tolerance by up-regulating the antioxidative defense mechanisms resulting in better biomass production and grain yield.

Biochemical responses and ultrastructural changes in ethylene insensitive mutants of Arabidopsis thialiana subjected to bisphenol A exposure.

Bisphenol A (BPA), an important raw material in plastic industry, has become a serious environmental contaminant due to its wide spread use in different products and increasing release into the environment. BPA is known to cause adverse effects in living organisms including plants. Several studies reported that BPA affects growth and development in plants, mainly through oxidative stress. Plants are known to generally cope with stress mainly through hormonal regulation and adaptation, but little is known about the role of plant hormones in plants under BPA stress. The present study was conducted to investigate the role of ethylene in BPA induced oxidative stress in plants using Arabidopsis thaliana as a test plant. The response of ethylene insensitive mutants of Arabidopsis (ein2-1 and etr1-3) to BPA exposure was studied in comparison to the wild type Arabidopsis (WT). In all three genotypes, exposure to BPA adversely affected cellular structures, stomata and light-harvesting pigments. An increase in reactive oxygen species (ROS) lipid peroxidation and other oxidative stress markers indicated that BPA induced toxicity through oxidative stress. However, the overall results revealed that WT Arabidopsis had more pronounced BPA induced damages while ein2-1 and etr1-3 mutants withstood the BPA induced stress more efficiently. The activity of antioxidant enzymes and expression of antioxidants related genes revealed that the antioxidant defense system in both mutants was more efficiently activated than in WT against BPA induced oxidative stress, which further evidenced the involvement of ethylene in regulating BPA induced oxidative stress. It is concluded that ethylene perception and signaling may be involved in BPA induced oxidative stress responses in plants.

Genome-wide identification of membrane-bound fatty acid desaturase genes in Gossypium hirsutum and their expressions during abiotic stress.

Membrane-bound fatty acid desaturases (FADs) are of great importance and play multiple roles in plant growth and development. In the present study, 39 full-length FAD genes, based on database searches, were identified in tetraploid upland cotton (Gossypium hirsutum L.) and were phylogenetically clustered into four subfamilies. Genomic localization revealed that 34 genes were mapped on 22 chromosomes, and five genes were positioned on the scaffold sequences. The FAD genes of G. hirsutum in the same subfamily had similar gene structures. The structures of paralogous genes were considerably conserved in exons number and introns length. It was suggested that the FAD gene families in G. hirsutum might be duplicated mainly by segmental duplication. Moreover, the FAD genes were differentially expressed in different G. hirsutum tissues in response to different levels of salt and cold stresses, as determined by qRT-PCR analysis. The identification and functional analysis of FAD genes in G. hirsutum may provide more candidate genes for genetic modification.

Chlorpyrifos and lambda cyhalothrin-induced oxidative stress in human erythrocytes.

Pesticides are one of the most potentially harmful chemicals introduced into the environment, and their adverse impacts on non-target organisms can be significant. The present study was conducted to shed light on effects of locally used insecticides chlorpyrifos (CPF) and lambda cyhalothrin (LCT) on oxidative stress biomarkers in human erythrocytes. The activity of catalase (CAT), superoxide dismutase (SOD), and protein contents as well as the levels of malondialdehyde (MDA) and osmotic fragility (OF) were measured in human erythrocytes exposed to CPF at concentrations of 0, 100, 500, 1000, and 2000 ppm and LCT at concentrations of 0, 100, 300, 600, and 800 ppm for 1 h and 3 h at 37°C. MDA levels and OF of erythrocytes were significantly higher in erythrocytes incubated with CPF and LCT at increasing concentrations of both insecticides and increased incubation time. However, erythrocyte CAT and SOD activities were decreased at all concentrations of CPF and LCT tested. Protein oxidation products were decreased at lower doses of CPF (100 and 500 ppm); at higher doses (1000 and 2000 ppm), total protein content was increased compared with control. In contrast LCT was associated with decreased in protein contents at all the concentrations. These results clearly demonstrated that CPF and LCT can induce oxidative stress in human erythrocytes ( in vitro).

Genome-Wide SNP Linkage Mapping and QTL Analysis for Fiber Quality and Yield Traits in the Upland Cotton Recombinant Inbred Lines Population.

It is of significance to discover genes related to fiber quality and yield traits and tightly linked markers for marker-assisted selection (MAS) in cotton breeding. In this study, 188 F8 recombinant inbred lines (RILs), derived from a intraspecific cross between HS46 and MARCABUCAG8US-1-88 were genotyped by the cotton 63K single nucleotide polymorphism (SNP) assay. Field trials were conducted in Sanya, Hainan Province, during the 2014-2015 cropping seasons under standard conditions. Results revealed significant differences (P < 0.05) among RILs, environments and replications for fiber quality and yield traits. Broad-sense heritabilities of all traits including fiber length, fiber uniformity, micronaire, fiber elongation, fiber strength, boll weight, and lint percentage ranged from 0.26 to 0.66. A 1784.28 cM (centimorgans) linkage map, harboring 2618 polymorphic SNP markers, was constructed, which had 0.68 cM per marker density. Seventy-one quantitative trait locus (QTLs) for fiber quality and yield traits were detected on 21 chromosomes, explaining 4.70∼32.28% phenotypic variance, in which 16 were identified as stable QTLs across two environments. Meanwhile, 12 certain regions were investigated to be involved in the control of one (hotspot) or more (cluster) traits, mainly focused on Chr05, Chr09, Chr10, Chr14, Chr19, and Chr20. Nineteen pairs of epistatic QTLs (e-QTLs) were identified, of which two pairs involved in two additive QTLs. These additive QTLs, e-QTLs, and QTL clusters were tightly linked to SNP markers, which may serve as target regions for map-based cloning, gene discovery, and MAS in cotton breeding.

Leaf-based physiological, metabolic, and ultrastructural changes in cultivated cotton cultivars under cadmium stress mediated by glutathione.

Cadmium (Cd) pollution is present in the world over especially in the industrialized parts of the world. To reduce Cd accumulation in various crops especially food crops, alleviating agents such as reduced glutathione (GSH) can be applied, which are capable either to exclude or to sequester Cd contamination. This study investigated the leaf-based spatial distribution of physiological, metabolic, and microstructural changes in two cotton cultivars (Coker 312 and TM-1) under GSH-mediated Cd stress using single levels of Cd (50 µM) and GSH (50 µM) both separately and in mix along with control. Results showed that GSH revived the morphology and physiology of both cotton cultivars alone or in mix with Cd. Cd uptake was enhanced in all segments of leaf and whole leaf upon the addition of GSH. GSH alleviated Cd-induced reduction in the photosynthetic pigment compositions and chlorophyll a fluorescence parameters. Mean data of biomarkers (2,3,5-triphenyltetrazolium (TTC), total soluble protein (TSP), malondialdehyde (MDA), hydrogen peroxide (H2O2)) revealed the adverse effects of Cd stress on leaf segments of both cultivars, which were revived by GSH. The oxidative metabolism induced by Cd stress was profoundly influenced by exogenous GSH application. The microstructural alterations were mainly confined to chloroplastic regions of leaves under Cd-stressed conditions, which were greatly revived upon the GSH addition. As a whole, Cd stress greatly affected TM-1 as compared to Coker 312. These results suggest a positive role of GSH in alleviating Cd-mediated changes in different leaf sections of cotton cultivars.

Alleviation of lead-induced physiological, metabolic, and ultramorphological changes in leaves of upland cotton through glutathione.

Plants face changes in leaves under lead (Pb) toxicity. Reduced glutathione (GSH) has several functions in plant metabolism, but its role in alleviating Pb toxicity in cotton leaves is still unknown. In the present study, cotton seedlings (28 days old) were exposed to 500 µM Pb and 50 µM GSH, both alone and in combination, for a period of 10 days, in the Hoagland solution under controlled growth conditions. Results revealed Pb-induced changes in cotton's leaf morphology, photosynthesis, and oxidative metabolism. However, exogenous application of GSH restored leaf growth. GSH triggered build up of chlorophyll a, chlorophyll b, and carotenoid contents and boosted fluorescence ratios (F v/F m and F v/F 0). Moreover, GSH reduced the malondialdehyde (MDA), hydrogen peroxide (H2O2), and Pb contents in cotton leaves. Results further revealed that total soluble protein contents were decreased under Pb toxicity; however, exogenously applied GSH improved these contents in cotton leaves. Activities of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione reductase (GR), and ascorbate peroxidase (APX)) were also increased by GSH application under Pb toxicity. Microscopic analysis showed that excess Pb shattered thylakoid membranes in chloroplasts. However, GSH stabilized ultrastructure of Pb-stressed cotton leaves. These findings suggested that exogenously applied GSH lessened the adverse effects of Pb and improved cotton's tolerance to oxidative stress.

Effect of some commonly used pesticides on seed germination, biomass production and photosynthetic pigments in tomato (Lycopersicon esculentum).

Pesticides are highly toxic substances. Their toxicity may not be absolutely specific to the target organisms but can adversely affect different processes in the non-target host plants. In the present study, the effect of over application of four commonly used pesticides (emamectin benzoate, alpha-cypermethrin, lambda-cyhalothrin and imidacloprid) was evaluated on the germination, seedling vigor and photosynthetic pigments in tomato. The obtained results revealed that seed germination was decreased by the pesticides and this effect was more prominent at early stages of exposure. All the tested pesticides reduced the growth of tomato when applied in higher concentration than the recommended dose, but at lower doses the pesticides had some stimulatory effects on growth as compared to the control. A similar effect of pesticides was observed on the photosynthetic pigments, i.e. a decrease in pigments concentrations was caused at higher doses but an increase was observed at lower doses of pesticides. The calculation of EC50 values for different parameters revealed the lowest EC50 values for emamectin (ranged as 51-181 mg/L) followed by alpha-cypermethrin (191.74-374.39), lambda-cyhalothrin (102.43-354.28) and imidacloprid (430.29-1979.66 mg/L). A comparison of the obtained EC50 values for different parameters of tomato with the recommended doses revealed that over application of these pesticides can be harmful to tomato crop. In a few cases these pesticides were found toxic even at the recommended doses. However, a field based study in this regard should be conducted to further verify these results.

Congenital cholesteatoma: Different clinical presentation in two cases.

INTRODUCTION: Congenital cholesteatoma (CC) of the middle ear is a rare entity that may be undiagnosed for years. The lesion can grow undetected until it produces symptoms such as reduced hearing or otalgia. METHOD: Case report. RESULTS: We report two cases of young ladies with CC who presented with different otological symptoms. The first case complained of recurrent unilateral ear pain while the second case presented with unilateral reduced hearing. Examination of both cases revealed a whitish mass seen behind an intact tympanic membrane. Both cases underwent surgery and histopathological examinations; findings were consistent with cholesteatoma. CONCLUSION: There are varieties of clinical presentations of CC and the diagnosis is based on clinical findings.

Pretreatment with salicylic acid and ascorbic acid significantly mitigate oxidative stress induced by copper in cotton genotypes.

Higher uptake and translocation of copper (Cu) into plant tissues can cause serious physiological and biochemical alterations in root and leaf tissues of plants. The present study investigates the ameliorative role of salicylic acid (SA) and ascorbic acid (AsA) against Cu-induced toxicity changes in cotton genotypes (two parental lines (J208, Z905) and their hybrid line (ZD14)). To study the tolerance potential against Cu (100 µM) stress, 2-week-old cotton seedlings were pretreated with 100 µM either SA or AsA for three days. Elevated Cu concentration in nutrient media increased Cu accumulation in roots and shoots of all the three cotton genotypes studied. Roots were the main Cu storage site, followed by leaves and stems. Increased cellular Cu concentration significantly inhibited the root and shoot development, although leaf growth was more sensitive toward Cu toxicity. Cu-induced oxidative stress to cotton leaves was evident from significantly increased hydrogen peroxide (H2O2) contents and lipid membrane damage. Increasing Cu translocation toward cotton leaves strongly influenced the malondialdehyde (MDA) contents, which, in turn, inhibited biomass production. SA and AsA pretreated cotton seedlings showed better growth under Cu stress. Despite increase in overall Cu uptake, the SA-pretreated seedlings could defy Cu toxicity through inhibited Cu translocation and modification in the activities of antioxidative enzymes. Whereas, tolerance to Cu-induced toxicity in AsA pretreated plants was associated with Cu exclusion from tissues and reduction of the overall Cu uptake. The present study revealed that the alleviatory role of AsA was significantly higher than SA regarding Cu stress in our experimental cotton genotypes. Furthermore, the hybrid cotton genotype (ZD14) performed well followed by J208 and Z905 in the present experimental setup.

Ultrastructural, metabolic and proteomic changes in leaves of upland cotton in response to cadmium stress.

Present study explores physiological, biochemical and proteomic changes in leaves of upland cotton (ZMS-49) using 500 µM cadmium (Cd) along with control. Leaves' biomass and chlorophyll pigments decreased at 500 µM Cd. Cd contents in roots were higher than leaves. Levels of ROS ( [Formula: see text] and H2O2) both in vivo and in vitro and MDA contents were significantly increased. Chlorophyll parameters (F0, Fm, Fm(') and Fv/Fm), total soluble protein contents and APX showed a decline at 500 µM Cd. SOD, CAT and POD and GR activities significantly enhanced. Less ultrastructural alterations in leaves under Cd stress could be observed. Scanning micrographs at 500 µM Cd possessed less number of stomata as well as near absence of closed stomata. Cd could be located in cell wall, vacuoles and intracellular spaces. Important upregulated proteins were methionine synthase, ribulose 1,5-bisphosphate carboxylase, apoplastic anionic guaiacol peroxidase, glyceraldehydes-3-phosphate dehydrogenase (chloroplastic isoform) and ATP synthase D chain, (mitochondrial). Important downregulated proteins were seed storage proteins (vicilin and legumin), molecular chaperones (hsp70, chaperonin-60 alpha subunit; putative protein disulfide isomerase), ATP-dependent Clp protease, ribulose-1,5-bisphophate carboxylase/oxygenase large subunit. Increase in the activities of ROS-scavenging enzymes, less ultrastructural modification, Cd-deposition in dead parts of cells as well as active regulation of different proteins showed Cd-resistant nature of ZMS-49.

In vitro cadmium-induced alterations in growth and oxidative metabolism of upland cotton (Gossypium hirsutum L.).

Cadmium (Cd) is a toxic pollutant, which cause both dose- and time-dependent physiological and biochemical alterations in plants. The present in vitro study was undertaken to explore Cd-induced physiological and biochemical changes in cotton callus culture at 0, 550, 700, 850, and 1000 µM Cd for four different stress periods (7, 14, 21, and 28 days). At 1000 µM Cd, mean growth values were lower than their respective control. The cell protein contents decreased only after 7-day and 14-day stress treatment. At 550 µM Cd, malondialdehyde (MDA) contents decreased after various stress periods except 21-day period. Superoxide dismutase (SOD) activity at 1000 µM Cd improved relative to its respective controls in the first three stress regimes. Almost a decreasing trend in the hydrogen peroxide (H2O2) and peroxidase (POD) activities at all Cd levels after different stress periods was noticed. Ascorbate peroxidase (APX) activity descended over its relevant controls in the first three stress regimes except at 700 µM Cd after 14- and 21-day stress duration. Moreover, catalase (CAT) mean values significantly increased as a whole. From this experiment, it can be concluded that lipid peroxidation as well as reactive oxygen species (ROS) production was relatively higher as has been revealed by higher MDA contents and greater SOD, CAT activities.

Chromium (VI) uptake and tolerance potential in cotton cultivars: effect on their root physiology, ultramorphology, and oxidative metabolism.

Chromium (Cr) is present in our environment as a toxic pollutant, which needs to be removed using phytoremediation technology. In present study, two transgenic cotton cultivars (J208, Z905) and their hybrid line (ZD14) were used to explore their Cr uptake and tolerance potential using multiple biomarkers approach. Four different levels of Cr (CK, 10, 50, and 100 µM) were applied. Cr caused a significant reduction in root/shoot length, number of secondary roots, and root fresh and dry biomasses at 100 µM. Cr accumulated more in roots and was found higher in hybrid line (ZD14) as compared with its parent lines (J208, Z905) at all Cr stress levels (10, 50, and 100 µM). Cr translocation was less than 1 in all cultivars. Ultrastructural studies at 100 µM Cr showed an increase in number of nuclei and vacuoles and presence of Cr dense granules in dead parts of the cell (vacuoles/cell wall). Malondialdehyde (MDA), hydrogen peroxide (H2O2), total soluble proteins, superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) as a whole were upregulated with elevated levels of Cr. Higher Cr uptake by roots, accelerated metabolism, and Cr sequestration in dead parts of the cell indicate that these cotton cultivars can be useful for Cr accumulation and tolerance.

Impact assessment of cadmium toxicity and its bioavailability in human cell lines (Caco-2 and HL-7702).

Cadmium (Cd) is a widespread environmental toxic contaminant, which causes serious health-related problems. In this study, human intestinal cell line (Caco-2 cells) and normal human liver cell line (HL-7702 cells) were used to investigate the toxicity and bioavailability of Cd to both cell lines and to validate these cell lines as in vitro models for studying Cd accumulation and toxicity in human intestine and liver. Results showed that Cd uptake by both cell lines increased in a dose-dependent manner and its uptake by Caco-2 cells (720.15 µg mg(-1) cell protein) was significantly higher than HL-7702 cells (229.01 µg mg(-1) cell protein) at 10 mg L(-1). A time- and dose-dependent effect of Cd on cytotoxicity assays (LDH release, MTT assay) was observed in both Cd-treated cell lines. The activities of antioxidant enzymes and differentiation markers (SOD, GPX, and AKP) of the HL-7702 cells were higher than those of Caco-2 cells, although both of them decreased significantly with raising Cd levels. The results from the present study indicate that Cd above a certain level inhibits cellular antioxidant activities and HL-7702 cells are more sensitive to Cd exposure than Caco-2 cells. However, Cd concentrations <0.5 mg L(-1) pose no toxic effects on both cell lines.