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1.
These studies investigate the magnitude and valence state of chromium absorbed following plausible drinking water exposures to chromium(VI). Four adult male volunteers ingested a single dose of 5 mg Cr (in 0.5 liters deionized water) in three choromium mixtures: (1) Cr(III) chloride (CrCl3), (2) potassium dichromate reduced with orange juice (cr(III)-OJ); and (3) potassium dichromate [Cr(VI)]. Blood and urine chromium levels were followed for 1-3 days prior to and up to 12 days after ingestion. The three mixtures showed quite different pharmacokinetic patterns. CrCl3 was poorly absorbed (estimated 0.13% bioavailability) and rapidly eliminated in urine (excretion half-life, approximately 10 hr), whereas Cr(III)-OJ was absorbed more efficiently (0.60% bioavailability) but more slowly (half-life, approximately 17 hr), and Cr(VI) had the highest bioavailability (6.9%) and the longest half-life (approximately 39 hr). All three chromium mixtures caused temporary elevations in red blood cell (RBC) and plasma chromium concentrations, but the magnitude and duration of elevation showed a clear trend (Cr(VI) > Cr(III)-OJ > CrCl3). The data suggest that nearly all the ingested Cr(VI) was reduced to Cr(III) before entering the bloodstream based on comparison to RBC and plasma chromium patterns in animals exposed to high doses of Cr(VI). These findings support our prior work which suggests that water-soluble organic complexes of Cr(III) formed during the reduction of Cr(VI) in vivo explain the patterns of blood uptake and urinary excretion in humans at drinking water concentrations of 10 mg/liter or less.  相似文献   

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This study was designed to assess the morphological effects of a bolus infusion of PEG-hemoglobin on the heart, lung, liver, spleen and kidney of laboratory rats. Of particular interest was the determination of PEG-hemoglobin's potential to form vacuoles in the tissues and whether these were transitory and article specific. One hundred ten female Sprague-Dawley rats were used in this study. The first experiment determined whether vacuole formation was test article specific by infusing either stroma-free bovine hemoglobin, PEG-hemoglobin, bovine serum albumin, PEG-bovine serum albumin or free PEG. The second experiment assessed the transitory nature of vacuolization. In both experiments, unconscious rats received an intravenous top-loading (bolus) injection of test article via the tail vein. Rats were sacrificed at various time points following administration and had their tissues examined for the presence of vacuoles by light microscope morphological examination and iron staining. Formation of vacuoles appeared to be test article specific with only prolonged circulating, high solute test articles producing vacuoles. These vacuoles appeared dose responsive and transitory in nature. The vacuolization found was non-toxic and believed to be due to the known effect of lysosomal overloading following the phagocytosis of vascularly persistent high solute test articles.  相似文献   

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The authors report on the perforation of the sigmoid colon in a 48-year-old male following the accidental ingestion of a partial dental plate. Sharp, pointed objects may perforate the bowel and surgery should be considered. A review of the literature revealed no previously reported cases.  相似文献   

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The body's equilibrium is possible thanks to the integration of skeletal structure, vertebrae, ligaments and muscles to form one functional unity. The forces which determine posture are composed of two complementary systems, the ligamentary and the muscular systems, which together determine a dynamic act of balance. The ligaments operate mainly against the visco-hydraulic pressure of the nucleus pulposus and bind the vertebral bodies together, whereas the muscles exhibit an antigravity function and support spinal stability. A mathematical model based on a mixed theory of directed and oriented curves is proposed. Through this model it is possible to develop an exact theory governing the deformation of the ligamentous spine. This theory should be universal in the sense that it can be used to supply the spine in any of its environments.  相似文献   

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A second administration of one half MAC enflurane for two hours one week following a previous identical exposure caused no increase in urinary inorganic Fluoride excretion (UFV). At this dosage of 1 MAC hour, which is equivalent to use as a supplement, UFV did not sub-anaesthetic doses of enflurane are administered at this time interval there appears to be no increased risk of nephrotoxicity. This study also provides strong support for the concept that drug metabolism is very reproducible within individuals but there is considerable variation between individuals. Since the subjects in this study were all of similar age, and drug free, the results are in keeping with recent twin studies which indicate that individual differences in drug metabolism are largely determined on a genetic basis.  相似文献   

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1. A case of poisoning due to the raw root tuber of a Chinese medicinal plant, Alocasia macrorrhiza is presented. 2. The patient developed neurological (severe pain and numbness in the perioral area and throat) and gastrointestinal (nausea, vomiting, abdominal pain) symptoms immediately after eating the root tuber. 3. A macrorrhiza has properties and morphology very similar to another medical plant. A. odora. The root tuber of the latter is known to contain a neurotoxin sapotoxin.  相似文献   

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Selecting of strain a Musca domestica resistant to trichlorphon with Bi 58 (active ingredient: dimethoate) resulted in an only slight (1.33-fold) increase of the resistance to dimethoate between 1974 and 1975. In the same time the resistance to trichlorphon rose to 5.28 times the original degree. The resistance extends to some other organophosphates, especially malathion, dichlorvos and bromophos, but not to diazinon. Among the insecticides registered for control of flies in pig-sties Bi 58 has the greatest chance, though there exists neither a certainty for the decrease of the resistance to trichlorphon nor for the non-appearance of a resistance to dimethoate. To overcome the problem of flies in stables and sties, particularly in plants of industrial cattle-breeding, complex measures must be taken.  相似文献   

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PURPOSE: To describe dense vitritis as the primary manifestation of ocular syphilis in three human immunodeficiency virus (HIV)-positive patients and to determine the response of these patients to the established regimen for neurosyphilis. METHODS: Anti-Toxoplasma gondii IgM and IgG antibody titers, tuberculin skin test, chest radiograph, and serum angiotensin-converting enzyme level were obtained because tuberculosis, sarcoidosis, and toxoplasmosis were in the differential diagnosis. Two of the three patients were not known to have HIV infection at the time of initial examination and consented to HIV testing. Treponemal and nontreponemal tests were performed on serum and cerebrospinal fluid to establish a definitive diagnosis. Treatment for neurosyphilis was initiated, and daily ophthalmic examinations were performed, with careful attention to signs commonly associated with syphilitic eye disease. RESULTS: All three patients exhibited improvement in visual acuity and resolution of vitreous haze. There was no evidence of other signs of posterior uveitis. The one patient for whom there has been a 6-month follow-up showed no sequelae of his eye disease. CONCLUSIONS: Human immunodeficiency virus-positive patients with syphilis may present atypically dense vitritis. In these patients, vitritis may be the first manifestation of syphilis. The regimen for neurosyphilis provides effective therapy. Moreover, in some patients, syphilitic vitritis may be the initial manifestation of HIV disease.  相似文献   

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The fluoride (F) contents of ten alginate impression materials in powder form, were found to range from 0.44% to 2.42%. Plasma F concentrations showed no appreciable changes in five dental personnel exposed to aerosols of these powders during routine clinical work. Elevated plasma F levels (120-158 ng/ml) were recorded after ingesting 2 g (approximately 10 mg F) of Zelgan normal-set alginate. The bioavailability of F from the alginate was about 55% of the total F in the administered dose. It is concluded that routine clinical exposure to alginate does not cause any important change in plasma F levels, whereas accidental swallowing of alginate raises the plasma F level significantly.  相似文献   

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A case of ectopic ureter without urinary incontinence despite its ureteral orifice in the vestibulum is reported. A 2-year-and-9-month-old female was referred to our hospital with the pain of external genitalia, pollakisuria and macroscopic hematuria. Examination revealed a complete double system of the left upper tract with vestibular opening from the upper moiety. She did not show any signs of ureteric incontinence after the establishment of voiding habits. Because radioisotope (RI) scintigram showed apparent uptake in the upper half of the left kidney we performed left ureterocystoneostomy with psoas hitch procedure. We postulate that the incontinence mechanism is maintained when the running course of the ectopic ureter is through some portion of the urethral sphincter musculature. This is the 10th case reported in Japan.  相似文献   

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In the mouse, the process of implantation is initiated by the attachment reaction between the blastocyst trophectoderm and uterine luminal epithelium that occurs at 2200-2300 h on day 4 (day 1 = vaginal plug) of pregnancy. Several members of the EGF family are considered important in embryo-uterine interactions during implantation. This investigation demonstrates that the expression of two additions to the family, betacellulin and epiregulin, are exquisitely restricted to the mouse uterine luminal epithelium and underlying stroma adjacent to the implanting blastocyst. These genes are not expressed during progesterone-maintained delayed implantation, but are rapidly switched on in the uterus surrounding the implanting blastocyst following termination of the delay by estrogen. These results provide evidence that expression of betacellulin and epiregulin in the uterus requires the presence of an active blastocyst and suggest an involvement of these growth factors in the process of implantation.  相似文献   

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Recorded self-directed aggressive behavior in 11 rhesus macaques. 4 Ss were given 5-15% ethyl alcohol in various combinations; the others served as controls. Self-aggression increased with an increase in the amount of alcohol ingested, independent of thirst or reduced fluid intake. In contrast, alcohol has been reported to ameliorate self-mutilating behaviors of children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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We studied 40 patients with the clinical diagnostic of chronic urticaria from January to June, 1995 and excluded 4 patients who did not fulfilled the entry criteria. 29 women and 7 men with age from 4 to 62 years old. We performed a basic clinics history and the oral challenge tests (PRO) included Tartrazine (Ta), Sodium Metabisulfite (MS), Potasium Metabisulfite (MP) and Sodium Bisulfite (BS) in consecutive days with increasing doses unless an adverse reactions appear. Other tests included Skin Prick tests for food (PC), complete blood counts, coprology and immunology tests (IgE, IgA, IgM, IgG, C3, C4, Cel LE and ANA) and paranasal sinus X Ray. 63.8% (23/36) had positive PRO. 47.2% (17/36) positives to Ta,, 36.1% (13/36) to MS, 33.3% (12/36) to BS and 30.5% (11/36) to MP. 72.2% (26/36) had positive PC to one or more foods, 65.3% (17/26) besides had positive PRO. 41.1% (7/17) of the patients who had positive PRO and positive PC to foods had sinusitis. One patient (0.23%) had palpebral angioedema with PRO. The prevalence was 3.1%. Ta was the additive that cause more reactivity. It is possible to find reactivity to one or more additives in a patient with chronic urticaria.  相似文献   

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The effects of a training experience that involves foot shock on the endogenous phosphorylation of membrane-bound proteins from brain were studied. Crude membrane fractions were prepared from the cerebral cortex and neostriatum of animals that had been sacrificed by quick freezing. In vitro incubation of the membranes with gamma-32P-ATP, follwed by SDS-gel electrophoresis of the phosphorylated substrates, revealed that the phosphorylation of two protein components (designated F and H-I) increased in preparations from animals that were subjected to a training experience 24 hr prior to sacrifice. These effects were greater in preparations from the neostriatum than from the cerebral cortex, and were observed in experiments using both rats and mice. Although all trained animals showed a high phosphorylation of bands F and H-I, control animals showed a greater variability in the phosphorylation of these bands. The results indicate that the phosphorylation of specific proteins may play a mediatory role in the processing of experiential information.  相似文献   

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BACKGROUND: Traditional Chinese medicines often contain 'chuanwu' and 'caowu', the roots of certain Aconitum species which are thought to have an anti-inflammatory effect in many conditions. Excessive amounts of these materials, which contain diterpene alkaloids particularly aconitine, can produce toxic effects and occasional fatalities. AIMS: This study was conducted to document the adverse effects related to these herbal medicines which resulted in hospital admission and to determine the outcome in these patients. METHODS: A retrospective survey was conducted of patients admitted to the Prince of Wales Hospital, Hong Kong with suspected adverse effects from Chinese herbal medicines containing chuanwu or caowu over a two year period from 1989 to 1991. RESULTS: Eight patients were identified with features of mild to moderate intoxication including nausea and vomiting, paraesthesiae or numbness in the mouth and extremities, hypotension and ventricular extrasystoles. The management of aconitine poisoning is essentially supportive and in-hospital observation with ECG monitoring should be continued for at least 24 hours because of the risk of cardiovascular collapse and ventricular arrhythmias. The medical profession and general public should be alerted to the potential toxicity of these herbs and their usage should be controlled by legislation in Hong Kong as it is in some other countries.  相似文献   

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[2-14C]2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) was administered orally (304 ng/kg body-weight dose based upon an average 70-kg-body-weight subject) to 5 human colon-cancer patients (58 to 84 years old), as well as to F344 rats and B6C3F1 mice. Colon tissue was collected from the human subjects at surgery and from the rodents 3.5 to 6 hr after administration. Colon DNA-adduct levels and tissue available doses were measured by accelerator mass spectrometry (AMS). The mean levels of MeIQx in the histologically normal colon tissue were not different among the human (97 +/- 26 pg MeIQx/g), rat (133 +/- 15 pg/g) or mouse (78 +/- 10 pg/g) tissues; and no difference existed between the levels detected in human normal and tumor tissue (101 +/- 15 pg/g). Mean DNA-adduct levels in normal human colon (26 +/- 4 adducts/10(12) nucleotides) were significantly greater (p < 0.01) than in rats (17.1 +/- 1 adduct/10(12) nucleotides) or mice (20.6 +/- 0.9 adduct/10(12) nucleotides). No difference existed in adduct levels between normal and tumor tissue in humans. These results show that MeIQx forms DNA adducts in human colon at low dose, and that the human colon may be more sensitive to the effects of MeIQx than that of mice or rats.  相似文献   

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