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1.
J Dairy Sci ; 93(9): 4189-95, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20723693

ABSTRACT

The objective of this study was to investigate the effect of dietary supplementation with the disaccharides trehalose and cellobiose on antioxidant activity in rumen fluid, blood, and milk of dairy cows. Nine Holstein dairy cows housed in a free-stall barn were divided into 3 groups, with each group receiving a different dietary treatment (a control diet, a 1% trehalose-supplemented diet, or a 1% cellobiose-supplemented diet) following a 3x3 Latin square design. Feed intake and milk production increased in cows receiving the trehalose-supplemented diet compared with those receiving the control and cellobiose-supplemented diets. The total protozoa numbers in the rumen fluid of cows fed trehalose- or cellobiose-supplemented diets were greater than those of the control group. The C18:0 and C18:1 fatty acid content was increased in the milk of cows fed the trehalose-supplemented diet compared with that of the control group, and the C18:3n-3 fatty acid content in the milk of cows fed the cellobiose-supplemented diet was less than that of the control group. Plasma biochemical parameters were unchanged among the different treatments. In rumen fluid, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and superoxide dismutase activity were increased 2h after feeding in cows receiving the cellobiose-supplemented diet compared with the control group, and the concentration of thiobarbituric acid reactive substances in the rumen fluid of cows fed the cellobiose-supplemented diet was decreased. In contrast, the values of these parameters measured in the milk of cows fed the cellobiose-supplemented diet were no different from those of control cows. Dietary supplementation with trehalose did, however, bring about an improvement of the oxidative status of milk and blood in these animals compared with controls. These results provide the first evidence supporting the use of dietary disaccharides to decrease lipid peroxide levels and increase the antioxidant content of dairy cow milk. The findings suggest that disaccharides, particularly trehalose, might be useful as supplements for reducing oxidative stress and improving the quality of milk for human consumption, as well as possibly impairing the processes that give rise to lipid oxidation odor in dairy cow milk.


Subject(s)
Antioxidants/analysis , Dietary Supplements , Lipid Peroxides/analysis , Milk/chemistry , Trehalose/pharmacology , Animals , Cattle , Cellobiose/pharmacology , Diet/veterinary , Eating/drug effects , Eukaryota/drug effects , Fatty Acids/analysis , Female , Free Radical Scavengers/analysis , Gastric Juice/chemistry , Lactation/drug effects , Lipid Peroxidation/drug effects , Milk/drug effects , Milk/metabolism , Rumen/drug effects , Rumen/parasitology , Superoxide Dismutase/analysis
2.
J Clin Invest ; 90(3): 897-905, 1992 Sep.
Article in English | MEDLINE | ID: mdl-1326000

ABSTRACT

Although Escherichia coli strains possessing the K1 capsule are predominant among isolates from neonatal E. coli meningitis and most of these K1 isolates are associated with a limited number of 0 lipopolysaccharide (LPS) types, the basis of this association of K1 and certain 0 antigens with neonatal E. coli meningitis is not clear. The present study examined in experimental E. coli bacteremia and meningitis in newborn and adult rats whether or not the K1 capsule and/or O-LPS antigen are critical determinants in the development of meningitis. Rats received subcutaneously at K1 E. coli strain (018+K1+) or mutants lacking either the K1 capsule (018+K1-) or 0 side-chain (018-K1+). 12-24 h later, blood and cerebrospinal fluid (CSF) specimens were obtained for quantitative cultures. The isolation of E. coli from CSF was observed in both newborn and adult rats infected with K1+ strains regardless of LPS phenotype (018+ or 18-) who also developed a high degree of bacteremia (e.g., greater than 10(4) CFU/ml of blood). In contrast, none of the newborn and adult rats infected with 018+K1- and developing bacteremia of greater than 10(4) were found to have positive CSF cultures. These findings indicate that the presence of the K1 capsule and a high degree of bacteremia are key determinants in the development of E. coli meningitis, suggesting that there may be specific binding sites present in the brain which have an affinity for the K1 capsule and thus may be responsible for the entry of K1-encapsulated E. coli into the meninges.


Subject(s)
Antigens, Bacterial , Escherichia coli Infections/etiology , Meningitis, Bacterial/etiology , Polysaccharides, Bacterial/toxicity , Animals , Bacterial Capsules , Base Sequence , DNA Transposable Elements , Female , Lipopolysaccharides/toxicity , Molecular Sequence Data , Pregnancy , Rats , Rats, Inbred Strains , Sepsis/etiology
3.
Arch Neurol ; 41(2): 210-2, 1984 Feb.
Article in English | MEDLINE | ID: mdl-6691828

ABSTRACT

One month before death, a 63-year-old man with known lung carcinoma manifested a left third-nerve palsy and crossed ataxia. The oculomotor involvement began with a dilated left pupil and progressed to a complete left oculomotor nerve palsy, with the exception of nearly normal lid function. Pathologic examination revealed a solitary midbrain metastasis involving the left third-nerve nucleus and rootlets, with the exception of the caudal central oculomotor subnucleus and its outflow fibers.


Subject(s)
Adenocarcinoma/secondary , Brain Neoplasms/secondary , Ophthalmoplegia/complications , Adenocarcinoma/complications , Adenocarcinoma/pathology , Brain Neoplasms/complications , Brain Neoplasms/pathology , Humans , Lung Neoplasms , Male , Mesencephalon/pathology , Middle Aged , Ophthalmoplegia/pathology
4.
Arch Neurol ; 32(10): 699-701, 1975 Oct.
Article in English | MEDLINE | ID: mdl-1180734

ABSTRACT

Two siblings had what we believe to be a unique disorder manifested by stationary congenital ichthyosiform erythroderma coupled with a slowly progressive spastic weakness of adult onset. The disorder was presumably inherited as an autosomal recessive trait. The mechanism by which a genetic mutation would mediate this multiple organ system disorder is unknown.


Subject(s)
Ichthyosis/congenital , Muscle Spasticity/complications , Adult , Age Factors , Female , Humans , Ichthyosis/complications , Ichthyosis/genetics , Intelligence , Male , Middle Aged , Muscle Spasticity/genetics , Syndrome
5.
Arch Neurol ; 32(10): 669-71, 1975 Oct.
Article in English | MEDLINE | ID: mdl-1180728

ABSTRACT

A case of neurocutaneous melanosis with malignant leptomeningeal melanoma was seen in a black man. The presence of extracranial metastases was noted, and evidence is presented favoring the central nervous system as the primary source.


Subject(s)
Brain Diseases/complications , Brain Neoplasms/complications , Melanoma/complications , Melanosis/complications , Meninges , Nevus, Pigmented/complications , Adult , Brain/pathology , Brain Neoplasms/pathology , Humans , Male , Melanoma/pathology , Meninges/pathology , Neoplasm Metastasis , Spinal Cord Compression/etiology
6.
Neurology ; 37(3): 491-4, 1987 Mar.
Article in English | MEDLINE | ID: mdl-3822146

ABSTRACT

Two patients had upward nystagmus on forward gaze before they died with acute caudal brainstem dysfunction. Bilateral dorsal paramedian damage in the rostral medulla, involving the perihypoglossal nuclei, was probably the critical lesion responsible for upbeat nystagmus.


Subject(s)
Medulla Oblongata/pathology , Nystagmus, Pathologic/pathology , Adolescent , Aged , Cerebral Infarction/pathology , Female , Humans , Medulla Oblongata/blood supply , Pons/pathology
7.
Neurology ; 35(11): 1647-9, 1985 Nov.
Article in English | MEDLINE | ID: mdl-4058754

ABSTRACT

A 28-year-old man had a chronic locked-in syndrome following tentorial herniation caused by an epidural hematoma. Postmortem examination revealed bilateral corticospinal tract degeneration caudal to the midbrain, with infarction of the right internal capsule just rostral to the cerebral peduncle and pressure necrosis of the pyramidal portion of the left cerebral peduncle.


Subject(s)
Cerebral Hemorrhage/complications , Encephalocele/complications , Hematoma/complications , Quadriplegia/etiology , Adult , Cerebral Hemorrhage/pathology , Craniocerebral Trauma/complications , Craniocerebral Trauma/pathology , Encephalocele/pathology , Hematoma/pathology , Humans , Male , Quadriplegia/pathology
8.
Neurology ; 29(11): 1527-30, 1979 Nov.
Article in English | MEDLINE | ID: mdl-574209

ABSTRACT

We describe an autopsy-proven case of central pontine myelinolysis (CPM) with premortem computerized tomographic (CT) visualization of the lesion on two scans, performed with an interval of 2 weeks. This case demonstrates the capability of CT to support the clinical diagnosis of central pontine myelinolysis. Identification of the condition should facilitate prompt initiation of aggressive supportive care.


Subject(s)
Brain Diseases/diagnostic imaging , Demyelinating Diseases/diagnostic imaging , Pons/diagnostic imaging , Humans , Male , Middle Aged , Tomography, X-Ray Computed
9.
Neurology ; 34(8): 1046-52, 1984 Aug.
Article in English | MEDLINE | ID: mdl-6540384

ABSTRACT

A 27-year-old woman who had undergone extensive small bowel resection at age 14 months developed kyphoscoliosis, ocular palsies, constricted visual fields, retinitis pigmentosa, progressive ataxia, muscular weakness, nearly absent vibration and impaired position sense, areflexia, extensor plantar responses, and macrocytic anemia. Her condition closely resembled Bassen-Kornzweig disease, but lipoprotein electrophoresis was normal. Mild fat malabsorption, lactic acidosis, and severe deficiency of vitamins A and E and carotene were documented. Serum B12 and folic acid levels were normal. During vitamin A and E therapy sufficient to elevate serum levels to the normal range, there was improvement of visual fields and visual acuity in dim light, lactic acidosis, and red cell volume. Progression of symptoms was halted during vitamin replacement therapy, and her gait improved. This syndrome is the human counterpart to vitamin E deficiency in experimental animals.


Subject(s)
Cerebellar Diseases/etiology , Intestine, Small/surgery , Spinal Cord Diseases/etiology , Vitamin E Deficiency/etiology , Adult , Cerebellar Diseases/drug therapy , Cerebellar Diseases/pathology , Female , Humans , Postoperative Complications/etiology , Postoperative Complications/pathology , Spinal Cord Diseases/pathology , Syndrome , Vision Disorders/etiology , Vitamin E/therapeutic use , Vitamin E Deficiency/complications , Vitamin E Deficiency/drug therapy , Vitamin E Deficiency/pathology
10.
Neurology ; 35(12): 1695-701, 1985 Dec.
Article in English | MEDLINE | ID: mdl-3877883

ABSTRACT

We studied a 69-year-old man with multiple brain infarcts who died 8 days after being studied with positron emission tomography and (F-18)-fluorodeoxyglucose. Metabolic abnormalities were greater than structural changes in size and extent. They were found in areas with no gross pathologic abnormalities. Remote metabolic effects were attributed both to degeneration of fiber tracts with disconnection of remote structures, as demonstrated by hypometabolism in the left frontal cortex associated with an infarct in the genu of the left internal capsule, and to microscopic infarcts not apparent on gross examination but manifested as hypometabolic regions.


Subject(s)
Cerebral Infarction/metabolism , Glucose/metabolism , Tomography, Emission-Computed , Aged , Cerebral Infarction/diagnostic imaging , Humans , Male
11.
Sleep ; 9(1 Pt 2): 126-32, 1986.
Article in English | MEDLINE | ID: mdl-3704435

ABSTRACT

This article describes the neuropathologic findings in a woman who died suddenly at the age of 48 after having had symptoms of narcolepsy for 1 1/2 years. Gross examination of the brain showed an arachnoid cyst. The significant light microscopic findings consisted of focal gliosis of the ventrolateral caudal pons and the periventricular anterior hypothalamus. Although cases of symptomatic narcolepsy have been previously reported, to our knowledge structural brain changes in idiopathic narcolepsy have not been previously described. In the present case, there is no evidence that the narcoleptic symptoms were secondary to any other disorder, including the arachnoid cyst. This patient's symptoms may be related to the pontine and hypothalamic gliosis, the etiology for which is unknown.


Subject(s)
Hypothalamus, Anterior/pathology , Narcolepsy/pathology , Pons/pathology , Arachnoid , Cysts/complications , Female , Gliosis , Humans , Middle Aged , Narcolepsy/complications , Narcolepsy/etiology
12.
J Am Geriatr Soc ; 43(11): 1243-7, 1995 Nov.
Article in English | MEDLINE | ID: mdl-7594158

ABSTRACT

BACKGROUND: The clinical diagnosis of dementia continues to be flawed. Although the diagnosis of Alzheimer's disease (AD) is better than 90% at research centers in highly selected patients, the diagnosis of patients with non-AD dementias and atypical AD patients is poor. Single photon emission computed tomography (SPECT) is a functional imaging technique touted as a diagnostic technique for the degenerative disorders. However there have been few clinicopathological studies using SPECT. METHODS: Twenty-seven consecutive dementia patients were evaluated clinically at a University-based specialty dementia clinic, and a diagnosis of a specific dementia was made. SPECT imaging was used in helping to select a clinical diagnosis. The correlations between clinical, SPECT and autopsy diagnoses were analyzed. RESULTS: Single photon emission computed tomography predicted pathologic diagnosis in 25 of 27 patients with dementia (92.6%), compared with clinical diagnosis, which was confirmed in 20/27 (74.1%). Distinct patterns were associated with dementia caused by AD, Fronto-Temporal Dementia (FTD), and Jakob-Creutzfeldt Disease (JCD). Vascular insults not seen with computerized tomography (CT) or magnetic resonance imaging (MRI) were found with SPECT. Three different pathologies were found in patients with Parkinsonian-Dementias (PD): Lewy-Body Variant of AD, Diffuse Lewy-bodies without plaques, and substantia nigra neuronal loss without plaques or Lewy-bodies. All showed a temporal-parietal pattern with SPECT that was similar to AD. CONCLUSION: SPECT provides useful positive information in dementia, particularly the differentiation of AD, FTD, and JCD. However, it does not distinguish PD from AD.


Subject(s)
Alzheimer Disease/diagnostic imaging , Dementia/diagnostic imaging , Tomography, Emission-Computed, Single-Photon , Adult , Aged , Aged, 80 and over , Alzheimer Disease/pathology , Creutzfeldt-Jakob Syndrome/diagnostic imaging , Creutzfeldt-Jakob Syndrome/pathology , Dementia/pathology , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Predictive Value of Tests
13.
Arch Ophthalmol ; 93(10): 991-5, 1975 Oct.
Article in English | MEDLINE | ID: mdl-1180757

ABSTRACT

When the diagnosis of optic glioma is made, the visual loss is most often mildly or profoundly impaired. We report the details of the unusual situation where central visual acuity, visual fields, and color vision were normal at the time a large optic nerve glioma was demonstrated in a young boy. To our knowledge, this is the first case report containing ophthalmologic, neuroradiologic, surgical, and histologic details illustrating the rare association of normal vision and an optic glioma.


Subject(s)
Glioma/physiopathology , Optic Nerve Diseases/physiopathology , Peripheral Nervous System Neoplasms , Vision, Ocular , Child , Glioma/pathology , Humans , Male , Optic Nerve/pathology , Optic Nerve Diseases/pathology
14.
Am J Clin Pathol ; 77(3): 363-70, 1982 Mar.
Article in English | MEDLINE | ID: mdl-6176114

ABSTRACT

Drechslera spicifera is a dematiaceous fungus which occurs widely in nature but only rarely has been implicated in animal and human infections. Previous infections have occurred in superficial and subcutaneous sites or were encountered in immunologically compromised hosts. This report documents a case of granulomatous encephalitis due to Drechslera spicifera in an immunologically competent woman with no known underlying disease, from whom the fungus was isolated. Animal pathogenicity studies in mice reproduced the histopathologic features, and the fungus was reisolated from the animals.


Subject(s)
Brain/microbiology , Encephalitis/microbiology , Mitosporic Fungi/isolation & purification , Mycoses/microbiology , Adult , Animals , Brain/pathology , Brain Abscess/diagnostic imaging , Brain Abscess/microbiology , Encephalitis/diagnostic imaging , Encephalitis/pathology , Female , Humans , Mice , Staining and Labeling , Tomography, X-Ray Computed
15.
J Neurol ; 240(7): 391-406, 1993 Jul.
Article in English | MEDLINE | ID: mdl-8410079

ABSTRACT

We reviewed the clinical, radiographic, and pathologic features of 15 patients with the acquired immune deficiency syndrome (AIDS) and progressive multifocal leukoencephalopathy (PML). Brain tissue from 10 autopsy and 6 biopsy specimens was studied using: in situ hybridization (ISH) for JC virus (JCV), immunohistochemistry for human immunodeficiency virus (HIV) p24 antigen, and electron microscopy. Thirteen patients presented with focal neurologic deficits, while 2 presented with a rapid decline in mental status. PML was commonly the initial opportunistic infection of AIDS and produced hemiparesis, dementia, dysarthria, cerebellar abnormalities, and seizures. Magnetic resonance imaging was more sensitive than computed tomography in detecting lesions, and often showed multifocal areas of PML. CD4+ T-cell counts were uniformly low (mean 84/mm3), except in 1 patient who improved on 3'-azido-3'-deoxythymidine (AZT). PML involved the cerebral hemispheres, brain stem, cerebellum, and cervical spinal cord. The distribution of brain involvement was consistent with hematogenous dissemination of the virus. In 2 brain specimens, multiple HIV-type giant cells were present within the regions involved by PML. When co-infection by HIV and papovavirus was present, PML dominated the pathological picture. ISH for JCV showed virus in the nuclei of oligodendrocytes and astrocytes. Occasionally there was staining for JCV in the cytoplasm of glial cells and in the neuropil, the latter possibly a correlate of papovavirus spread between myelin sheaths, as seen by electron microscopy. ISH demonstrated more extensive foci of PML than did routine light microscopy.


Subject(s)
Acquired Immunodeficiency Syndrome/complications , Leukoencephalopathy, Progressive Multifocal/complications , Adult , Brain/diagnostic imaging , Brain/pathology , Female , Follow-Up Studies , Humans , Immunohistochemistry , In Situ Hybridization , Leukoencephalopathy, Progressive Multifocal/diagnostic imaging , Leukoencephalopathy, Progressive Multifocal/pathology , Magnetic Resonance Imaging , Male , Microscopy, Electron , Middle Aged , Retrospective Studies , Tomography, X-Ray Computed
16.
AJNR Am J Neuroradiol ; 8(2): 221-7, 1987.
Article in English | MEDLINE | ID: mdl-3105279

ABSTRACT

A number of CT head scans, covering a 2-year period and showing a variety of distinct curvilinear subinsular lucent lesions, were collected and reviewed. Variations in extent of involvement, tendency toward bilateral symmetry, and clinical background allowed the lesions to be grouped into four general patterns, most of which, to our knowledge, have not been specifically described in the radiologic literature. This project was undertaken first to bring to the attention of those involved in interpretation of cranial CT images several patterns of injury they may not heretofore have been aware of and second to attempt to derive a specific etiology for each of the patterns described. Pattern 1, which appears as a distinct curvilinear lesion (sometimes cystic) apparently limited to the lateral aspect of the putamen, is thought to represent the residua of previous lateral striatal hemorrhage. Pattern 2, occurring in a markedly younger age group appears as relatively symmetrical bilateral subinsular lucencies, which in one case completely resolved. A specific etiology for this pattern remains uncertain. Acute demyelination, either secondary to a variant of anoxic leukoencephalopathy or to a limited form of diffuse encephalomyelitis, is postulated. A third pattern, which extends from generalized deep frontal white-matter lucency across the anterior limb of the internal capsule and tapering posteriorly in the subinsular area is thought to be on the basis of chronic ischemia similar to subcortical arteriosclerotic encephalopathy. The fourth pattern, occurring as a broad band of lucency extending from the frontal horn of the lateral ventricle and also tapering posteriorly is due to relatively proximal occlusion of the lateral lenticulostriate arteries.


Subject(s)
Brain Ischemia/diagnostic imaging , Cerebral Infarction/diagnostic imaging , Corpus Striatum/blood supply , Adolescent , Adult , Aged , Aged, 80 and over , Brain Ischemia/complications , Cerebral Infarction/etiology , Corpus Striatum/diagnostic imaging , Female , Humans , Infant , Male , Middle Aged , Retrospective Studies , Tomography, X-Ray Computed
17.
AJNR Am J Neuroradiol ; 14(4): 929-39, 1993.
Article in English | MEDLINE | ID: mdl-8179647

ABSTRACT

PURPOSE: To describe the MR imaging features of cerebellar medulloblastoma in the adult. MATERIALS AND METHODS: The neuroimages and records of 15 adults with proved cerebellar medulloblastoma were retrospectively evaluated. In 12 patients, preoperative MR scans were reviewed; nine had Gd-DTPA-enhanced scans. RESULTS: Of the 12 tumors evaluated preoperatively, eight were hemispheric, two hemispheric-vermian, and two vermian. Tumor margins were well demarcated, except in three cases, two of which had large infiltrative tumors. In 10 cases, tumor extended to the brain surface, and in five of these, contiguity with the tentorium or cerebellopontine angle cistern was such than an extraaxial tumor was considered. The tumors were typically hypointense on T1 but a spectrum was seen on T2-weighted images. Enhancement ranged from minimal and patchy to marked. One tumor became isointense after Gd-DTPA. Other features included cystic changes, hemorrhage, exophytic invasion at the cerebellopontine angle, spinal cerebrospinal fluid seeding, intraventricular seeding, and bone metastasis. CONCLUSION: Although there is no pathognomonic MR appearance of adult cerebellar medulloblastoma, the finding of a well-demarcated, mild to moderately enhancing hemispheric mass involving the brain surface in a young adult is suggestive of medulloblastoma. Awareness that this tumor may resemble meningioma may avoid misdiagnosis and aid surgical planning.


Subject(s)
Cerebellar Neoplasms/diagnosis , Magnetic Resonance Imaging , Medulloblastoma/diagnosis , Adolescent , Adult , Cerebellar Neoplasms/epidemiology , Contrast Media , Diagnosis, Differential , Female , Gadolinium DTPA , Humans , Male , Medulloblastoma/epidemiology , Middle Aged , Neoplasm Recurrence, Local/epidemiology , Organometallic Compounds , Pentetic Acid , Retrospective Studies
18.
Neurosurgery ; 4(4): 319-24, 1979 Apr.
Article in English | MEDLINE | ID: mdl-450231

ABSTRACT

We present a patient with a recurrent intracerebral blastomycotic granuloma. The computerized tomographic scan appearance of this lesion is illustrated. Of the 81 reported cases of intracranial blastomycosis, only 35 have represented solid intracerebral lesions; the other patients have had spinal lesions or meningitis. This patient represents the first reported recurrence of an intracerebral blastomycotic granuloma. The treatment utilized, surgical resection combined with intravenous and intraventricular amphotericin B, represents a unique approach to this problem. The diagnosis and currently advocated treatment of intracranial blastomycosis is reviewed, particularly in regard to the potential for recurrence of blastomycosis.


Subject(s)
Amphotericin B/administration & dosage , Blastomycosis/therapy , Brain Diseases/therapy , Granuloma/therapy , Adult , Blastomycosis/diagnosis , Blastomycosis/pathology , Brain Diseases/diagnosis , Brain Diseases/pathology , Granuloma/diagnosis , Granuloma/pathology , Humans , Injections, Intravenous , Male , Recurrence
19.
Talanta ; 40(1): 101-6, 1993 Jan.
Article in English | MEDLINE | ID: mdl-18965601

ABSTRACT

A redox reaction of copper(II) with iron(II) proceeds slowly in the presence of neocuproine, although the reaction would not take place in its absence. This reaction is accelerated by the presence of complexing agents such as EDTA, DTPA, CyDTA, EDTA-OH, NTA, citrate, pyrophosphate, producing a copper(I)-neocuproine complex (lambda(max) = 454 nm). A reverse flow injection analysis (r-FIA) method is presented for the determination of trace amounts of complexing agents by measuring the increase in absorbance at 454 nm. Complexing agents at the 10(-6)M level can be determined at a rate of 120 samples/hr. By using this r-FIA system, a new procedure for the measurement of complexing capacity with metal ions such as Al(III), Cu(II), Zn(II), Cd(II) and Pb(II) has been developed. Complexing capacity for each metal ion can be measured at a rate of 120 samples/hr.

20.
Talanta ; 45(3): 549-55, 1998 Jan.
Article in English | MEDLINE | ID: mdl-18967036

ABSTRACT

A new catalytic method for the determination of silver(I) was developed based on a metal exchange reaction between ethylenediaminetetraacetatomercury(II) (Hg(II)-EDTA) in the aqueous phase and bis(diethyldithiocarbamato)copper(II) (Cu(II)-DDTC) in the organic phase. This exchange reaction (Cu(II)-DDTC(org)+Hg(II)-EDTA-->Hg(II)-DDTC(org)+Cu(II)-EDTA, where org denotes the organic phase) was observed to proceed slowly and the Cu(II)-DDTC complex transferred quantitatively to Hg(II)-complex in the organic phase in the equilibrium state. In this system, silver(I) acts as the catalyst and can be determined by measuring the decrease in the absorbance of the Cu(II)-DDTC complex (lambda(max)=435 nm). The reaction was applied to the extractive flow injection analysis of silver(I). The present method allows the determination of silver(I) at 10(-7) mol dm(-3) level with the sampling frequency of 30 h(-1). The relative standard deviation of 0.28% (n=10) was obtained at 4.0x10(-7) mol dm(-3) of silver(I).

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