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1.
J Environ Manage ; 226: 448-456, 2018 Nov 15.
Article in English | MEDLINE | ID: mdl-30144783

ABSTRACT

The study endeavors the anaerobic treatment of cyanide-containing effluents using the hybrid anaerobic reactor, with self-immobilized granules under high up-flow velocities. Comparison of one-year time-course analyses of HARs treating high strength effluents containing cyanide and control indicates the importance of wastewater characteristics in development and maintenance of microbiome. Efforts were directed towards associating process performance with microbial dynamics. Presence of cyanide results in the accumulation of intermediates paralleled with a drop in abundance of sensitive aceticlastic methanogens. HAR appear to have better resilience than other identified digesters because of shielding effects and enhanced granule-wastewater contact. The predominance of Methanobacteriales in the presence of cyanide can be linked to its tolerance. It was found that methane yield is positively correlated with abundance of aceticlastic guilds (R = 0.830, CI = 0.01). Tolerant bacterial groups were also identified. The study advances our knowledge related to less energy intensive technology with the focus on the development of efficient HAR.


Subject(s)
Bioreactors , Cyanides/isolation & purification , Anaerobiosis , Cyanides/chemistry , Methane , Sewage , Wastewater , Water Purification
2.
J Toxicol Environ Health A ; 63(3): 221-35, 2001 Jun 08.
Article in English | MEDLINE | ID: mdl-11405417

ABSTRACT

A bolus dose of cadmium metallothionein (CdMT) produces renal proximal tubular dysfunction because it accumulates in the tubular epithelial cells and undergoes rapid degradation, releasing Cd. Morphologically, mitochondria appear to be the target organelle. The present study examined changes in renal cortical mitochondrial function following CdMT administration and investigated whether some of these effects could be ascribed to Cd2+ accumulation in the mitochondria. Sprague-Dawley rats were injected ip with 0.3 mg Cd as CdMT/kg and the animals were sacrificed after 6, 8, or 12 h. Two- to threefold increases in urinary protein excretion and LDH activity were evident at 8 h, with marked elevations (11- and 29-fold) thereafter. Renal cortical mitochondria were swollen and rounded at 12 h. The mitochondrial Cd level was 399 pmol/mg protein at 6 h and did not change significantly during the next 6 h; however, mitochondrial respiratory function declined with time. At 12 h, state 3 oxygen consumption, respiratory control ratio (RCR), and ADP:O (P/O) ratio were 48, 49, and 76% of control values, respectively, indicating inhibition of electron transfer and oxidative phosphorylation. The direct effect of Cd on mitochondrial function was examined by incubating mitochondria from untreated rats with 0.1-2 microM CdCl2. Rapid uptake of Cd resulted in concentration-dependent effects on respiration. After 1 min of incubation with 2 microM Cd, the mitochondria contained 262 microgCd/mg protein and state 3 respiration and RCR values were 75 and 33% of control levels, respectively. Thus, renal proximal tubular cell damage following a bolus dose of CdMT involves perturbations in mitochondrial respiration, brought on by the accumulation of Cd.


Subject(s)
Kidney Cortex/drug effects , Kidney Tubules, Proximal/drug effects , Metallothionein/toxicity , Mitochondria/drug effects , Analysis of Variance , Animals , Disease Models, Animal , Dose-Response Relationship, Drug , Female , In Vitro Techniques , Kidney Cortex/pathology , Kidney Tubules, Proximal/pathology , L-Lactate Dehydrogenase/urine , Metallothionein/pharmacokinetics , Mitochondria/pathology , Mitochondrial Swelling/drug effects , Oxidative Phosphorylation/drug effects , Oxygen Consumption/drug effects , Proteins/metabolism , Rats , Rats, Sprague-Dawley , Time Factors
3.
Article in English | MEDLINE | ID: mdl-11381787

ABSTRACT

In order to identify some causal relations among various urinary indices of cadmium-induced renal dysfunction, such as glucose, total protein, amino nitrogen, beta 2-microglobulin (beta 2-m), metallothionein (MT), and cadmium (Cd), we applied path analysis method to previous epidemiological studies targeting the residents of the Cd-polluted Kakehashi River basin of Ishikawa Prefecture, Japan. We obtained a diagram-termed path model, representing some causal relations among the above urinary indices. It shows that urinary Cd is located at the beginning point in the diagram, and Cd-induced renal dysfunction develops in the following order: Cd exposure-->increase of beta 2-m and/or MT excretion-->increase of amino-N and/or total protein excretion-->increase of glucose excretion. It was proved mathematically, that in the case of both males and females, increased excretions of beta 2-m and/or MT were the most sensitive urinary indices of the early stage of chronic Cd-induced renal dysfunction.


Subject(s)
Cadmium/adverse effects , Environmental Pollutants/adverse effects , Kidney Diseases/etiology , Models, Theoretical , Aged , Biomarkers/urine , Cadmium/urine , Epidemiologic Studies , Female , Humans , Male , Middle Aged , Proteinuria , Risk Assessment , beta 2-Microglobulin/urine
4.
J Neurol Sci ; 185(1): 19-26, 2001 Mar 15.
Article in English | MEDLINE | ID: mdl-11266686

ABSTRACT

Cortical and subcortical gray matter hypointensities on T2-weighted MR images (T2WI) occur commonly in MS brains and have been related to disease duration, clinical course, and the level of neurologic disability. These hypointensities have been reported to occur in the thalamus, basal ganglia, and rolandic cortex. We assessed whether T2 hypointensity is associated with the severity of white matter plaques and atrophy of MS brains. In 114 MS patients, hypointensity of the thalamus, putamen, caudate, and sensorimotor cortex was ordinally rated against age- and gender-matched normal controls on 1.5-T MRI fast spin-echo axial T2WI. Regional and global T2 hyperintense and T1 hypointense parenchymal lesion loads were ordinally rated. Enlargement of subarachnoid and ventricular spaces (atrophy) was ordinally rated vs. age- and gender-matched normal controls. T2 hypointensity was highly, positively correlated with many other MRI variables. Regression modeling showed that T2 hypointensity was related to total atrophy, total T2 lesion load, third ventricular enlargement, parietal atrophy, and to a lesser extent, frontal T1 lesions and cerebellar T2 lesions, but not related to gadolinium enhancement. Ordinal ratings of T2 lesions and central atrophy showed high correlations with quantitative computerized assessments. We conclude that gray matter hypointensity on T2WI may reflect pathologic iron deposition and brain degeneration in MS. This T2 hypointensity is associated with brain atrophy and other MR markers of tissue damage. Further study is warranted to determine if T2 hypointensity is predictive of disease course in MS and is a useful surrogate outcome measure in therapeutic trials.


Subject(s)
Brain/pathology , Magnetic Resonance Imaging , Multiple Sclerosis/pathology , Adolescent , Adult , Atrophy , Female , Follow-Up Studies , Humans , Male , Middle Aged , Plaque, Amyloid/pathology
5.
J Child Neurol ; 15(10): 696-9, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11063086

ABSTRACT

Moyamoya disease is a chronic occlusive cerebrovascular disorder. It can occur as a primary disease or as a syndrome associated with a variety of conditions. Usually it takes 1 to 2 years to develop a classic moyamoya pattern. We report a 20-month-old girl with Down syndrome and moyamoya syndrome who presented with seizure and hemiparesis. To our knowledge, this is the youngest case reported with moyamoya syndrome and Down syndrome. The prognosis and current treatment of moyamoya syndrome and its relation to Down syndrome are reviewed. There is some reason to speculate that the abnormalities associated with Down syndrome might create a vulnerability for the development of moyamoya syndrome.


Subject(s)
Down Syndrome/complications , Moyamoya Disease/complications , Moyamoya Disease/diagnosis , Age Factors , Atrophy/pathology , Cerebral Cortex/pathology , Cerebral Cortex/surgery , Female , Humans , Infant , Magnetic Resonance Angiography , Magnetic Resonance Imaging , Moyamoya Disease/surgery
6.
J Neuroimaging ; 10(3): 180-3, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10918747

ABSTRACT

A 74-year-old man had diplopia, painful right ophthalmoplegia, proptosis, conjunctival injection, and facial skin lesions. Magnetic resonance imaging (MRI) revealed infiltration of the right intraorbital adipose tissue. Lesions were mixed low- and high-signal on T2-weighted images and enhanced on fat-suppressed T1-weighted postcontrast images. A skin biopsy revealed numerous noncaseating granulomas consistent with sarcoidosis. Treatment with corticosteroids and chlorambucil led to a full clinical recovery. Sarcoidosis should be considered in the evaluation of orbital pseudotumor in elderly patients, even if no systemic manifestations of sarcoidosis are present.


Subject(s)
Magnetic Resonance Imaging , Orbital Diseases/diagnosis , Sarcoidosis/diagnosis , Aged , Diagnosis, Differential , Humans , Male , Orbit/pathology
7.
Mult Scler ; 6(3): 181-5, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10871830

ABSTRACT

We studied multiple sclerosis fatigue (MSF) and its relationship to depression and disability. Seventy-one patients [50 relapsing-remitting, 21 secondary progressive] were grouped by Fatigue Severity Scale (FSS) into MS-fatigue (MSF) (FSS>/=5; n=46) or MS-nonfatigue (MSNF) (FSS

Subject(s)
Depression/etiology , Disabled Persons/psychology , Fatigue/etiology , Multiple Sclerosis/physiopathology , Multiple Sclerosis/psychology , Nervous System/physiopathology , Adult , Depression/psychology , Fatigue/physiopathology , Fatigue/psychology , Female , Humans , Male , Middle Aged , Multiple Sclerosis/complications , Severity of Illness Index
8.
Neuroreport ; 11(6): 1153-8, 2000 Apr 27.
Article in English | MEDLINE | ID: mdl-10817583

ABSTRACT

It is unclear whether brain MRI lesions are associated with depression in multiple sclerosis (MS). Neurological dysfunction in depressed (n= 19) and non-depressed (n = 29) MS patients was rated by expanded disability status scale (EDSS). EDSS was weakly predictive of the presence of (p = 0.03) and severity of (p = 0.01) depression. After correcting for EDSS, the presence of depression was predicted by superior frontal and superior parietal hypointense TI lesions (p<0.01); the severity of depression was predicted by superior frontal, superior parietal and temporal TI lesions, lateral and third ventricular enlargement, and frontal atrophy (p<0.01). Depression was not related to bright T2 lesions or enhancement. We conclude that atrophy and cortical-subcortical disconnection due to frontal and parietal white matter destructive lesions may contribute to depression in MS.


Subject(s)
Depression/etiology , Frontal Lobe/pathology , Magnetic Resonance Imaging , Multiple Sclerosis/complications , Multiple Sclerosis/pathology , Parietal Lobe/pathology , Adult , Atrophy/etiology , Atrophy/pathology , Demyelinating Diseases/etiology , Demyelinating Diseases/pathology , Depression/diagnosis , Female , Frontal Lobe/physiopathology , Humans , Male , Middle Aged , Neuropsychological Tests , Parietal Lobe/physiopathology , Predictive Value of Tests , Third Ventricle/pathology
9.
Neuroreport ; 11(1): 15-21, 2000 Jan 17.
Article in English | MEDLINE | ID: mdl-10683822

ABSTRACT

Abnormal iron deposition occurs in the brains of patients with multiple sclerosis (MS) and may cause MRI T2 shortening ('black T2'; BT2). The frequency, distribution and clinical significance of BT2 in MS is unknown. Analysis of brain MRI scans of 114 MS patients showed BT2 in thalamus (n = 65; 57%), putamen (n = 48; 42%), caudate (n = 27; 24%) and Rolandic cortex (n = 9; 8%). BT2 was significantly related to longer disease duration and advancing neurological disability. Wheelchair-bound patients had worse BT2 in thalamus (p < 0.05), putamen (p < 0.001) and Rolandic cortex (p < 0.05). Patients with secondary progressive disease (n = 34) had worse BT2 in thalamus, putamen and caudate (all p < 0.05) than those with relapsing remitting disease (n = 80). BT2 is proposed as a clinically relevant finding relating to neuronal degeneration in MS.


Subject(s)
Multiple Sclerosis/pathology , Adolescent , Adult , Brain Chemistry/physiology , Disease Progression , Female , Humans , Iron/metabolism , Magnetic Resonance Imaging , Male , Middle Aged , Multiple Sclerosis/metabolism , Recurrence
10.
J Neuroimaging ; 10(4): 223-5, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11147402

ABSTRACT

Bell's palsy (idiopathic facial paralysis) is the most common cause of unilateral peripheral facial neuropathy. Bilateral involvement occurs in less than 10% of cases. The authors describe a 20-year-old man with bilateral idiopathic facial weakness. Brain magnetic resonance imaging (MRI) showed abnormal bilateral enhancement of the proximal intracanalicular segments of VII/VIII nerve complexes. The enhancement was most prominent in the leptomeningeal regions. There was no facial nerve swelling. Three months later he had improving residual bifacial weakness. To the authors' knowledge, this is the first report of abnormal MRI findings in bilateral Bell's palsy.


Subject(s)
Bell Palsy/diagnosis , Magnetic Resonance Imaging , Adult , Arachnoid/pathology , Bell Palsy/physiopathology , Cochlear Nerve/pathology , Facial Muscles/physiopathology , Facial Nerve/pathology , Humans , Image Enhancement , Male , Muscle Weakness/physiopathology , Pia Mater/pathology
11.
Neurology ; 53(5): 1151-3, 1999 Sep 22.
Article in English | MEDLINE | ID: mdl-10496289

ABSTRACT

Fatigue is an unexplained but common and disabling symptom in MS. We assessed fatigue in 71 patients with MS and identified MS-fatigue (MSF) and MS-nonfatigue (MSNF) groups. Fatigue severity did not correlate with regional or global MRI plaque load or atrophy assessed by conventional sequences. No significant differences were noted in any MRI measures between MSF and MSNF groups. We suggest that brain MRI disease topography or severity does not explain fatigue in MS and that fatigue is likely due to mechanisms poorly characterized by conventional MRI.


Subject(s)
Fatigue/pathology , Multiple Sclerosis/pathology , Adult , Brain/pathology , Fatigue/etiology , Female , Humans , Magnetic Resonance Imaging , Male , Multiple Sclerosis/complications
12.
J Neuroimaging ; 9(3): 134-40, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10436754

ABSTRACT

Intracranial lipomas are histologically benign and usually incidental magnetic resonance imaging findings that must be differentiated from ominous lesions. The authors describe 32 lipomas in 30 patients using conventional spin-echo (CSE) T1-weighted images (T1WI), CSE proton density (PDWI), CSE T2-weighted images (T2WI), fast spin-echo (FSE) T2WI, and FSE fluid-attenuated inversion recovery (FLAIR). Lipomas occurred most commonly in the trigonal choroid plexus, cerebral convexity, pericallosal, and quadrigeminal cistern regions. Lipomas were hyperintense on CSE T1WI and of variable appearance on CSE PDWI and CSE T2WI. Lipomas were isointense to hyperintense on FSE T2WI and hyperintense on FLAIR. Chemical shift artifact (CSA) usually was present on either CSE PDWI or CSE T2WI but was not seen on FSE images. One patient had intracranial hypotension associated with a large convexity lipoma. The authors conclude that lipomas appear different on CSE T2WI than on FSE T2WI. CSE PDWI and CSE T2WI are complementary in detecting CSA. The lack of CSA being detected in lipomas on FSE images most likely relates to inherent bandwidth differences compared with those of CSE. The hyperintense appearance of lipomas on FSE FLAIR and FSE T2WI may be confused with subacute hematomas. The authors recommend that if CSE technique by itself is used to exclude lipomas (in centers that are not using FSE), then T1WI, PDWI, and T2WI usually are sufficient. For centers using FSE routinely, fat saturation or CSE sequences also may be needed to exclude lipomas. Finally, the authors' series suggests that intracranial lipomas may occur in lateral locations more frequently than reported previously.


Subject(s)
Brain Neoplasms/diagnosis , Lipoma/diagnosis , Magnetic Resonance Imaging , Artifacts , Brain/pathology , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged
13.
Toxicology ; 132(2-3): 139-46, 1999 Feb 15.
Article in English | MEDLINE | ID: mdl-10433377

ABSTRACT

A Japanese drug containing glycine, glycyrrhizin, and cysteine (Stronger Neo-Minophagen C) has been reported to protect against chronic cadmium (Cd) toxicity. The present study was conducted to evaluate which of the three constituents of this drug was the main antagonist for Cd toxicity and whether the mechanism of protection involved antioxidant action. Adult female Sprague-Dawley rats were injected sc with 5 micromol CdCl2/kg per day, five times per week, for 15 weeks. Four groups of Cd-injected animals received co-treatments with either 10 mg glycyrrhizin/kg, 100 mg glycine/kg, 5 mg cysteine/kg, or with a mixture of all three compounds, five times per week, starting from week 7. An additional Cd-injected group was co-treated with vitamin E (100 mg/kg, five times per week, starting from week 7) as a positive control. Only those animals that received vitamin E, Minophagen mixture, or glycine were protected against Cd-induced hepatotoxicity as well as nephrotoxicity. All three co-treatments suppressed Cd-induced hepatic and renal lipid peroxidation. We conclude that the reported beneficial effects of Stronger Neo-Minophagen C are due to glycine, which appears to protect against chronic Cd toxicity by reducing oxidative stress.


Subject(s)
Cadmium/toxicity , Glycine/pharmacology , Animals , Cadmium/pharmacokinetics , Female , Kidney/drug effects , Lipid Peroxidation/drug effects , Liver/drug effects , Oxidative Stress , Rats , Rats, Sprague-Dawley
14.
J Toxicol Environ Health A ; 57(3): 211-22, 1999 Jun 11.
Article in English | MEDLINE | ID: mdl-10376887

ABSTRACT

Acute cadmium-metallothionein (CdMT) injection is frequently used as a model to study the mechanism of chronic Cd-induced nephrotoxicity. The purpose of this study was to investigate the relationship between glutathione (GSH) status and the ability of CdMT, either administered as a bolus dose or infused over a 24-h period by an osmotic minipump, to cause nephrotoxicity. GSH levels were modulated by pretreatment with either buthionine sulfoximine (BSO) or GSH. BSO enhanced while GSH suppressed acute CdMT nephrotoxicity. An infused dose of CdMT (150 microg Cd/kg) that was well tolerated when delivered over a 24-h period became nephrotoxic when GSH synthesis was inhibited by BSO. With depletion of GSH, as little as 0.4 microg Cd/g renal cortex was sufficient to cause nephrotoxicity after an acute dose of CdMT. While BSO had no effect on renal Cd accumulation, pretreatment with GSH reduced renal cortical Cd accumulation by 36%. CdMT nephrotoxicity was enhanced by depleting renal GSH, but without increasing renal Cd accumulation, which suggests that intracellular GSH is directly involved in protection against CdMT nephrotoxicity. Reduced Cd accumulation in the renal cortex following GSH pretreatment suggests an additional extracellular mechanism of GSH protection. It is concluded that GSH status is an important determinant of CdMT nephrotoxicity, with low GSH levels enhancing and high GSH levels reducing its toxicity, and that the mechanism appears to involve both intracellular and extracellular sites.


Subject(s)
Cadmium Compounds/toxicity , Glutathione/pharmacology , Kidney/drug effects , Metallothionein/toxicity , Animals , Dose-Response Relationship, Drug , Drug Interactions , Female , Infusions, Intravenous , Injections, Intravenous , Rats , Rats, Sprague-Dawley
15.
J Anal Toxicol ; 23(3): 153-8, 1999.
Article in English | MEDLINE | ID: mdl-10369323

ABSTRACT

Urinary metallothionein (MT) is a biological marker of cadmium (Cd) exposure and Cd-induced renal dysfunction. The MT is prone to oxidation due to high cysteine content and forms polymers, which can result in overestimation of the protein by immunochemical methods. The objectives of the present study were to develop an enzyme-linked immunosorbent assay (ELISA) for the measurement of MT in urine and to find ways by which the protein could either be preserved in its monomeric form or converted to this form before analysis to avoid overestimation. Urine specimens analyzed were either from rats repeatedly injected with Cd or from individuals chronically exposed to cadmium through their diets. The MT in rat urine remained in the monomeric form if the urine was collected at 4 degrees C but did not if it was collected at room temperature. The MT was also polymerized if the urine was subjected to repeated freezing and thawing. Overestimation of MT in rat urine occurred (as much as 12-fold) if the MT was polymerized. Addition of 5mM mercaptoethanol to freshly collected rat urine retarded MT polymerization, and addition of 50mM mercaptoethanol converted the polymerized MT to its monomeric form. Analysis of MT in frozen human urine samples revealed that if the urines were not treated with mercaptoethanol, the estimates of MT concentration were up to 11-fold higher than in the treated samples. We conclude that the polymerization of MT in rat and human urines is a serious problem and results in overestimation of the protein by ELISA and that this problem could be overcome by the addition of mercaptoethanol to the urine samples prior to analysis.


Subject(s)
Cadmium/toxicity , Metallothionein/urine , Polymers/metabolism , Aged , Animals , Biomarkers/urine , Drug Stability , Environmental Exposure , Female , Food Contamination , Freezing , Humans , Kidney Diseases/chemically induced , Kidney Diseases/urine , Male , Metallothionein/biosynthesis , Metallothionein/metabolism , Rats , Rats, Sprague-Dawley , Sheep
16.
Toxicology ; 133(2-3): 93-103, 1999 Apr 15.
Article in English | MEDLINE | ID: mdl-10378476

ABSTRACT

Exposure to cadmium (Cd) can result in nephrotoxicity and osteotoxicity. Because Cd-induced nephrotoxicity involves oxidative stress and caloric restriction decreases oxidative stress, we examined whether reduced caloric intake will protect against Cd-induced nephrotoxicity. In addition, the protection against the osteotoxicity was also examined. Male and female Sprague-Dawley rats were provided drinking water containing 100 mg Cd/l. Since fluid intake relative to the body weight was higher in females as compared to the males, the Cd concentration in their water was reduced to 80 mg/l after 3 months and 65 mg/l after 6.5 months. During the 27 month exposure period the males and females consumed a total of about 5 g Cd/kg body weight. Food was restricted to 20 g/day after the first 3 months. During the unrestricted food intake period Cd exposure reduced the bone density in females by 23%, with a partial recovery and stabilization during the caloric restriction phase. Hepatic and renal Cd accumulation and corresponding metallothionein (MT) levels were very similar in both sexes. The reported critical Cd concentration for nephrotoxicity was reached by 9 months. Renal MT levels were maximum at this time. Despite a 1.5-fold increase in renal Cd concentration over the next 18 months, there was no significant increase in renal MT levels. In spite of high renal Cd levels and lack of availability of sufficient MT, there was no sign of nephrotoxicity, as measured by urinary protein and glucose excretion. It is concluded that caloric restriction prevents Cd-induced nephrotoxicity and also appears to control the osteotoxicity of Cd.


Subject(s)
Cadmium/toxicity , Energy Intake , Animals , Body Weight/physiology , Bone Density/drug effects , Bone Density/physiology , Bone Diseases/chemically induced , Bone Diseases/diet therapy , Bone Diseases/prevention & control , Cadmium/pharmacokinetics , Drinking , Female , Kidney/drug effects , Kidney/metabolism , Kidney Diseases/chemically induced , Kidney Diseases/diet therapy , Kidney Diseases/prevention & control , Liver/metabolism , Male , Metallothionein/metabolism , Rats , Rats, Sprague-Dawley , Sex Factors
17.
Neurology ; 52(6): 1285-8, 1999 Apr 12.
Article in English | MEDLINE | ID: mdl-10214762

ABSTRACT

Clinical-neuroimaging analysis of 12 thrombotic thrombocytopenic purpura (TTP) patients revealed a variety of brain lesions. These included reversible cerebral edema lesions with MRI features of reversible posterior leukoencephalopathy syndrome (RPLS). Most of the RPLS patients had hypertension and renal dysfunction, suggesting RPLS due to hypertensive encephalopathy. Prompt treatment usually led to neurologic recovery and disappearance of edematous lesions. Those with infarcts or hematomas had a poorer outcome. TTP should be added to the expanding spectrum of RPLS and hypertensive encephalopathy.


Subject(s)
Purpura, Thrombotic Thrombocytopenic/diagnostic imaging , Purpura, Thrombotic Thrombocytopenic/pathology , Adult , Aged , Brain/diagnostic imaging , Brain/pathology , Child , Female , Humans , Magnetic Resonance Imaging , Male , Tomography, X-Ray Computed
18.
Toxicol Appl Pharmacol ; 154(3): 256-63, 1999 Feb 01.
Article in English | MEDLINE | ID: mdl-9931285

ABSTRACT

The role of oxidative stress in chronic cadmium (Cd) toxicity and its prevention by cotreatment with antioxidants was investigated. Adult female Sprague-Dawley rats were injected sc with 5 micromol CdCl2/kg/day, 5 times a week, for up to 22 weeks. Serum alanine amino transferase and lactate dehydrogenase activities were elevated after 9 weeks of Cd administration, indicating hepatic damage. Renal toxicity, indicated by elevation in urinary lactate dehydrogenase activity and protein, was also observed around this time. Chronic Cd administration resulted in a gradual rise in hepatic as well as renal cortex glutathione levels. In spite of this, lipid peroxidation increased in both tissues, particularly during the second half of the Cd exposure period. Depletion of glutathione following buthionine sulfoximine administration at the end of Week 5, or inhibition of catalase by aminotriazole at the end of Week 7, resulted in the development of acute nephrotoxicity within 6 h. Coadministration of antioxidants, N-acetylcysteine (50-100 mg/kg, sc), or vitamin E (100-150 mg/kg, sc) with Cd, starting from the early phases of Cd exposure, controlled Cd-induced lipid peroxidation and protected the animals against hepatic as well as renal toxicity. A Japanese hepatoprotective drug, Stronger Neo-Minophagen C, containing glycyrrhizin, glycine, and cysteine, was also effective in reducing the chronic Cd nephrotoxicity. In conclusion, oxidative stress appears to play a major role in chronic Cd-induced hepatic and renal toxicity since inhibition of components of the antioxidant defense system accelerated and administration of antioxidants protected against Cd toxicity.


Subject(s)
Antioxidants/pharmacology , Cadmium/toxicity , Kidney/drug effects , Liver/drug effects , Oxidative Stress/drug effects , Acetylcysteine/pharmacology , Alanine Transaminase/metabolism , Amitrole/pharmacology , Animals , Anti-Inflammatory Agents/pharmacology , Buthionine Sulfoximine/pharmacology , Cysteine/pharmacology , Drug Combinations , Enzyme Inhibitors/pharmacology , Female , Glutathione/metabolism , Glycine/pharmacology , Glycyrrhetinic Acid/analogs & derivatives , Glycyrrhetinic Acid/pharmacology , Kidney/metabolism , L-Lactate Dehydrogenase/metabolism , L-Lactate Dehydrogenase/urine , Lipid Peroxidation/drug effects , Liver/metabolism , Malondialdehyde/metabolism , Proteinuria/chemically induced , Rats , Rats, Sprague-Dawley , Steroids , Time Factors , Vitamin E/pharmacology
19.
Toxicol Lett ; 104(1-2): 137-42, 1999 Jan 11.
Article in English | MEDLINE | ID: mdl-10048759

ABSTRACT

Chronic cadmium (Cd)-induced nephrotoxicity is believed to be irreversible at advanced stages and no treatment is currently available. This study examined the beneficial effect of N-acetyl cysteine (NAC) on Cd-induced nephrotoxicity. Female Sprague-Dawley rats were injected s.c. with 5 micromol CdCl2/kg per day, five times/week for up to 26 weeks. Nephrotoxicity was detected after 10 weeks by elevation in urinary lactate dehydrogenase activity and protein. NAC co-administration from week 13 prevented the progression of nephrotoxicity. In these animals, with low-level nephrotoxicity, discontinuation of Cd exposure at the end of week 22 resulted in gradual recovery over the next several weeks, without the need for treatment with NAC. On the other hand, discontinuation of NAC co-treatment at the end of week 22 resulted in quick progression of nephrotoxicity, indicating that NAC protection was short-lived. Resumption of NAC treatment and cessation of Cd exposure after 26 weeks resulted in rapid recovery from advanced nephrotoxicity. It is concluded that protection from Cd-induced nephrotoxicity is possible by continued co-administration of NAC and that recovery from advanced nephrotoxicity can also be achieved with NAC, provided that Cd exposure is stopped.


Subject(s)
Acetylcysteine/therapeutic use , Cadmium Poisoning/prevention & control , Free Radical Scavengers/therapeutic use , Kidney Diseases/prevention & control , Animals , Cadmium Poisoning/enzymology , Cadmium Poisoning/pathology , Female , Kidney Diseases/chemically induced , Kidney Diseases/pathology , L-Lactate Dehydrogenase/metabolism , Rats , Rats, Sprague-Dawley , Time Factors
20.
Toxicol Appl Pharmacol ; 154(1): 59-66, 1999 Jan 01.
Article in English | MEDLINE | ID: mdl-9882592

ABSTRACT

Cadmium (Cd) is reported to produce cardiotoxicity at doses and exposure conditions that cause no effect in kidney or liver. The purpose of the present investigation was to examine the cytotoxicity of Cd to neonatal rat cardiomyocytes in primary culture and to elucidate the transport characteristics of Cd in these cells at a nontoxic concentration. Cd concentrations of 0.1 microM and higher that are well tolerated by hepatocytes and renal cortical epithelial cells were toxic to the cardiomyocyte. The plot of initial uptake rate of Cd at various concentrations was nonlinear suggesting that, in addition to simple diffusion, other processes may also be involved. These processes required metabolic energy as pretreatment with dinitrophenol or sodium fluoride inhibited 58 and 59% of the Cd uptake, respectively. The uptake of Cd was also affected by the incubation temperature and lowering the temperature from 37 to 4 degreesC reduced Cd uptake over 30 min by 61%. Cd uptake required interaction with membrane sulfhydryl groups; pretreatment with p-chloromercuribenzenesulfonic acid or mercuric chloride reduced Cd uptake by 46 and 58%, respectively. Cd utilized the transport pathways for calcium (Ca), zinc (Zn), and copper (Cu). Coincubation with 1.26 mM Ca competitively inhibited Cd uptake by 77%. In the presence of Ca, 30 microM Zn or Cu further inhibited Cd accumulation competitively by as much as 63 and 32%, respectively. Cd could enter the cardiomyocytes through Ca channels and Ca channel blocker, verapamil, inhibited up to 76% of Cd uptake. From the above results it can be concluded that Cd is highly toxic to the cardiomyocytes. A majority of Cd enters these cells through transport processes that exist for Ca, Zn, and Cu. The transport processes utilized by Cd are temperature sensitive and dependent on metabolic energy. Furthermore, these involve membrane sulfhydryl groups and include Ca channels.


Subject(s)
Cadmium/metabolism , Cadmium/toxicity , Heart Diseases/chemically induced , Myocardium/metabolism , Animals , Biological Transport , Cadmium/administration & dosage , Calcium/metabolism , Calcium/pharmacology , Cell Death , Cells, Cultured , Copper/metabolism , Copper/pharmacology , Kinetics , Rats , Rats, Sprague-Dawley , Sulfhydryl Reagents/pharmacology , Temperature , Zinc/metabolism , Zinc/pharmacology
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