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Biomedical subjects

J Rank

Publications and source records attributed to J Rank.

16 recordsLinked to original sources
PubMed2002

Genotoxicity of maleic hydrazide, acridine and DEHP in Allium cepa root cells performed by two different laboratories.

The purpose of this paper was to compare the results of the Allium cepa chromosome aberration assay between two laboratories under the same test protocol and at the same time, use chemicals and onions obtained in their own homeland. For this study three chemicals were selected: di(2-ethylhexyl)phthalate (DEHP), maleic hydrazide, and acridine. Both laboratories found genotoxicity with a positive dose-response relationship for maleic hydrazide and acridine. However, for DEHP the results were quite different--one of the laboratories found this compound not genotoxic but the other found a positive response. Although the comparative study was inconclusive for DEHP, it was successful for the maleic hydrazide, acridine and also for the positive control (methyl methanesulfonate). Further studies need to be performed in the case of DEPH.

Acridines↗
PubMed2001

Differences in cyclists and car drivers exposure to air pollution from traffic in the city of Copenhagen.

It has frequently been claimed that cycling in heavy traffic is unhealthy, more so than driving a car. To test this hypothesis, teams of two cyclists and two car drivers in two cars were equipped with personal air samplers while driving for 4 h on 2 different days in the morning traffic of Copenhagen. The air sample charcoal tubes were analysed for their benzene, toluene, ethylbenzene and xylene (BTEX) content and the air filters for particles (total dust). The concentrations of particles and BTEX in the cabin of the cars were 2-4 times greater than in the cyclists' breathing zone, the greatest difference being for BTEX. Therefore, even after taking the increased respiration rate of cyclists into consideration, car drivers seem to be more exposed to airborne pollution than cyclists.

Adult↗
PubMed2000

A model to predict poor survival in patients undergoing transjugular intrahepatic portosystemic shunts.

Transjugular intrahepatic portosystemic shunts (TIPS) may worsen liver function and decrease survival in some patients. The Child-Pugh classification has several drawbacks when used to determine survival in such patients. The survival of 231 patients at 4 medical centers within the United States who underwent elective TIPS was studied to develop statistical models to (1) predict patient survival and (2) identify those patients whose liver-related mortality post-TIPS would be 3 months or less. Among these elective TIPS patients, 173 had the procedure for prevention of variceal rebleeding and 58 for treatment of refractory ascites. Death related to liver disease occurred in 110 patients, 70 within 3 months. Cox proportional-hazards regression identified serum concentrations of bilirubin and creatinine, international normalized ratio for prothrombin time (INR), and the cause of the underlying liver disease as predictors of survival in patients undergoing elective TIPS, either for prevention of variceal rebleeding or for treatment of refractory ascites. These variables can be used to calculate a risk score (R) for patients undergoing elective TIPS. Patients with R > 1.8 had a median survival of 3 months or less. This model was superior to both the Child-Pugh classification, as well as the Child-Pugh score, in predicting survival. Using logistic regression and the same variables, we also developed a nomogram that indicates which patients survive less than 3 months. Finally, the model was validated among an independent set of 71 patients from the Netherlands. This Mayo TIPS model may predict early death following elective TIPS for either prevention of variceal rebleeding or for treatment of refractory ascites.

Adult↗
PubMed1998

Genotoxicity testing of wastewater sludge using the Allium cepa anaphase-telophase chromosome aberration assay.

Wastewater sludges were analysed in the Allium cepa genotoxicity test. They were sampled during three winter periods from three Danish municipal wastewater treatment plants differing in size and industrial load. The toxicity of the sludge was tested in the Allium root inhibition assay, and the results expressed as EC30 and EC50 values showed that the toxicity could be positive correlated to the industrial load. However, when genotoxicity was tested at concentrations corresponding to the EC30 and EC50 values in the A. cepa anaphase-telophase assay, only two sludge samples from the smallest plant with the lowest industrial load induced significant chromosome aberrations. Concentrations of the heavy metal's Pb, Ni, Cr, Zn, Cu, and Cd were also determined and could partly be correlated with the toxicity of the sludge and the industrial load of the treatment plants.

Anaphase↗
PubMed1997

Allium cepa anaphase-telophase root tip chromosome aberration assay on N-methyl-N-nitrosourea, maleic hydrazide, sodium azide, and ethyl methanesulfonate.

The Allium anaphase-telophase assay was used to show genotoxicity of N-methyl-N-nitrosourea (MNU), maleic hydrazide (MH), sodium azide (NaN3) and ethyl methanesulfonate (EMS). All agents induced chromosome aberrations at statistically significant levels. The rank of the lowest doses with positive effect was as follows: NaN3 0.3 mg/l < MH 1 mg/l < MNU 41 mg/l < EMS 100 mg/l. The results were compared with results from other plant assays (Arabidopsis, Vicia, Tradescantia) and for MH and MNU the values were found to be within the same range, whereas the results in the Allium test for NaN3 and EMS were in a lower range than that found for the other plant assays. EMS and MMS (methyl methanesulfonate), two chemicals used as positive controls in mutagenicity testing, were compared in the Allium test, and MMS was found to be about ten times more potent in inducing chromosome aberrations than EMS. Recording of micronuclei in interphase cells showed that this endpoint does not give more information of clastogenicity than recording of chromosome aberrations in anaphase-telophase cells.

Allium↗
PubMed1997

Endoscopic variceal ligation in pediatric patients with portal hypertension secondary to liver cirrhosis.

BACKGROUND: Endoscopic variceal ligation is the initial treatment of choice in the management of esophageal varices. Few reports include its use in the pediatric population. We review our experience with this therapeutic modality in pediatric patients with end stage liver disease and esophageal varices. METHODS: We reviewed the medical records of pediatric patients with end stage liver disease who underwent endoscopic variceal ligation from January 1994 until December 1996. RESULTS: Thirty-two endoscopic variceal ligation procedures were performed in six pediatric patients during the period of study. In all patients, the esophageal varices classification was improved at the end of treatment. Only one patient had an episode of bleeding from esophageal varices during the period of study; only one patients had a complication associated with endoscopic variceal ligation. CONCLUSIONS: Endoscopic variceal ligation is feasible, safe, and effective for the management of esophageal varices in pediatric patients with end stage liver disease.

Child↗
PubMed1995

Electrophoresis-tutor: an image-based personal computer program that teaches clinical interpretation of protein electrophoresis patterns of serum, urine, and cerebrospinal fluid.

High-resolution protein electrophoresis of serum, urine, and cerebrospinal fluid (CSF) can aid in the diagnosis of multiple myeloma, amyloidosis, macroglobulinemia, multiple sclerosis, and other diseases. Electrophoresis-Tutor is a personal computer program based on approximately 150 digital images that teaches the clinical interpretation of agarose gel electrophoretic patterns. The program is divided into the following sections: introduction, CSF, serum, urine, review of disease states, program navigator, and final exam. The CSF section describes normal and abnormal CSF findings with emphasis on oligoclonal banding, as seen in the CSF of patients with multiple sclerosis. The serum section emphasizes monoclonal gammopathy patterns but also has detailed descriptions of inflammation, liver disease, protein-losing disorders, genetic deficiencies, and other patterns. Monoclonal gammopathy is described in the context of specific associated clinical conditions (e.g., myeloma, amyloidosis). For each monoclonal gammopathy example, results of standard electrophoresis, densitometry, and immunofixation are presented. The review of disease states uses animation to illustrate the development and remission of a variety of pathological patterns. The program navigator allows the user to jump quickly to any place in the program. The optional exam contains 20 questions, and detailed feedback is given after each question. Electrophoresis-Tutor can be used as a stand-alone teaching tool, a companion to traditional instruction, or a reference source.

Blood Proteins↗
PubMed1994

Evaluation of the Allium anaphase-telophase test in relation to genotoxicity screening of industrial wastewater.

The Allium anaphase-telophase test was evaluated to find out if it could be recommended in the screening of wastewater for genotoxicity. Five mutagenic or carcinogenic chemicals usually found in wastewater were tested in the Allium anaphase-telophase test. Sodium dichromate (25 microM), benzene (100 microM), dichloromethane (175 microM) and 1,1,1-trichloromethane (175 microM) increased the frequency of chromosome aberrations in the root cells, whereas formaldehyde (1 mM) was found to be non-mutagenic in this test system. Other studies where chemicals were tested in the Allium test were reviewed. For 15 chemicals the results were compared with results from the Ames test, the Microscreen assay, and carcinogenicity tests in rodents. The sensitivity of the Allium test was calculated to be 82%. In conclusion the Allium test is recommended for the screening of wastewater because it has a high sensitivity, is cheap, rapid, easy to handle, and because it can be used on wastewater without pretreatment of the sample.

Allium↗
PubMed1994

Screening of toxicity and genotoxicity in wastewater by the use of the Allium test.

Wastewater was collected from two municipal wastewater treatment plants and twelve different industries representing five lines of business (chemical, metallic, petrochemical, pulp- and paper, and textile dye industries). Effect on the growth of Allium roots was measured after five days of exposure. Growth inhibition values, EC50 and EC30, showed no toxic effect for eight of the fourteen plants. The most toxic effect was found in wastewater from one of the pulp- and paper plants. Allium root tip cells were analyzed for chromosome aberrations after 24 h of exposure. Wastewater from nine of the fourteen plants was able to induce chromosome aberrations at a statistically significant level. The textile dye industry was the only line of business which did not show any genotoxic effect. Three of the plants (municipal wastewater, metallic, and pulp- and paper) showed genotoxicity in spite of being nontoxic in the growth inhibition experiment.

Allium↗
PubMed1993

Genotoxicity testing of the herbicide Roundup and its active ingredient glyphosate isopropylamine using the mouse bone marrow micronucleus test, Salmonella mutagenicity test, and Allium anaphase-telophase test.

The genotoxic potential of the herbicide Roundup and its active agent, glyphosate isopropylamine salt, was studied in three different assays. No clastogenic effects were found in the mouse bone marrow micronucleus test for either of the two agents. In the Salmonella assay only Roundup was tested. It showed a weak mutagenic effect for the concentrations 360 micrograms/plate in TA98 (without S9) and 720 micrograms/plate in TA100 (with S9). These concentrations are close to the toxic level. The anaphase-telophase Allium test showed no effect for the glyphosate isopropylamine salt, but a significant increase in chromosome aberrations appeared after treatment with Roundup at concentrations of 1.44 and 2.88 mg/l when calculated as glyphosate isopropylamine. The most frequent aberrations observed could be characterized as disturbances of the spindle.

Allium↗
PubMed1985

Molecular size of [3H]WB-4101-binding sites in rat cortex as determined by radiation inactivation.

The molecular weight of the [3H]WB-4101-binding sites in rat cerebral cortex was estimated by the irradiation-inactivation technique. The molecular weight was found to be dependent on the assay concentrations of the radioligand in the binding assay. Assays with a [3H]WB-4101 concentration of 0.25 nM showed a molecular weight of 62,100 daltons and 5.1 nM showed 50,800 daltons. Scatchard transformation of the [3H]WB-4101-binding data shows two binding sites (high-affinity: KD = 0.09 nM, Bmax = 9.1 pmoles/g; low-affinity: KD = 20 nM, Bmax = 80 pmoles/g). It is suggested that the two binding exist at two distinct molecules and in that case the observed molecular weights of 62,100 and 50,800 daltons are not true values because the determinations are carried out on a mixture of the two molecule populations. The distribution of the two binding sites was calculated for the two radioligand concentrations, 0.25 nM and 5.1 nM; and on this background the "true" molecular weights of the two [3H]WB-4101-binding sites were estimated to be 68,300 daltons for the high-affinity molecule and 41,400 daltons for the low-affinity molecule. Competition studies with a variety of adrenergic agonists and antagonists against [3H]WB-4101 supported the hypothesis that only the high-affinity binding site is an alpha-1-adrenoceptor.

Animals↗
PubMedDate not supplied

Changes in IgA following varying degrees of biliary obstruction in the rat.

Polymeric IgA is rapidly transported from blood to bile by the rat liver. The effect of varying degrees of biliary obstruction on this transport process was studied. IgA concentrations were measured by radioimmunoassay. Serum IgA concentrations increased progressively, and IgA output in bile declined with increasing bile duct obstruction. The decline in bile IgA output was explained by both diminished bile flow and decreased concentrations of IgA in bile. Very little polymeric IgA was present in normal rat serum. In contrast, using column chromatography on Ultrogel AcA 22, increases in serum IgA associated with cholestasis were shown to be due to increments in polymeric IgA. Serum IgA was a more sensitive indicator of cholestasis than was serum alkaline phosphatase. IgA and secretory component were found, using indirect immunofluorescence, surrounding bile canaliculi and on or adjacent to the hepatocyte plasma membrane lining the sinusoids. With biliary obstruction, staining for IgA and secretory component intensified markedly near the bile canaliculi. We conclude that: (a) polymeric IgA must be efficiently removed from serum by the normal rat liver; (b) even minimal cholestasis impairs IgA output into bile, and (c) impairment of IgA transport during cholestasis appears to occur at or near the canalicular membrane.

Animals↗
PubMedDate not supplied

Xylene induced feeding and drinking behavior and central adrenergic receptor binding.

Mice were exposed to 1600 ppm m-xylene 4 hours a day, 5 days a week in 7 weeks. At the end of exposure binding of 3H-clonidine to four brain regions was measured, and it was found that the binding was significantly decreased in the hypothalamus region but not altered in diencephalon, cortex and cerebellum. During the m-xylene exposure the mice ate and drank more than the control group, which resulted in a loss of weight for the controls compared to the exposed mice, when weighed before and after the 4 hours exposure. The results show that m-xylene can induce eating and drinking response in mice, and it is suggested that there is a connection between this phenomenon and the decrease in alpha-receptor binding in the hypothalamus region.

Animals↗