PubMed Health⌕ Search

Biomedical subjects

M Kohan

Publications and source records attributed to M Kohan.

13 recordsLinked to original sources
PubMed2003

Tetrasomy 12p--unusual presentation in CVS.

CVS direct preparations usually achieve limited resolution and are better at detecting numerical rather than structural abnormalities. A CVS direct preparation analyzed using G-banding revealed a 47,XY,+G karyotype in 5 of 11 cells and was reported as mosaic for trisomy 21. Subsequent analysis of the CVS culture found only normal male cells. Amniocentesis revealed both normal male cells and cells with an extra F-group chromosome. Fluorescence in situ hybridization (FISH) identified this chromosome to be an isochromosome from the short arm of chromosome 12 [i(12)(p10)]. The amniocyte karyotype was reported as 47,XY,+i(12)(p10)[12]/46,XY[8].ish i(12)(p10)(wcp12+), which is associated with Pallister-Killian syndrome. Reexamination of the CVS direct preparation by FISH with a chromosome 12 centromere probe confirmed the karyotype of this tissue to be 47,XY,+mar[5]/46,XY[6].nuc ish 12cen(D12Z3 x 3)/12cen(D12Z3 x 2). Thus, multiple studies, including amniocentesis and fluorescence in situ hybridization, may be required to fully and accurately evaluate abnormalities detected by CVS. This case also indicates that mosaicism for supernumerary isochromosomes may have a complex origin.

Abnormalities, Multiple↗
PubMed2001

[Iron deficiency anemia due to stromal tumor of the ileum].

Iron-deficiency anemia occurs in 3.5 to 5.3% of adult men and postmenopausal women. Occult gastrointestinal bleeding is the cause in the vast majority of cases. After endoscopic examinations have ruled out lesions in colon and upper gastrointestinal tract, 5 to 20% of those patients remain without diagnosis. Angiodysplasias and tumors are the most common causes of occult bleeding arising from the small bowel. Their diagnosis requires complex studies with quite low yield. However, it is necessary to perform them when anemia becomes severe or persistent. We report the case of a male patient with severe and persistent iron-deficiency anemia who had a stromal gastrointestinal tumor located in the ileum.

Anemia, Iron-Deficiency↗
PubMed1999

[Steatohepatic cirrhosis in a morbidly obese patient].

Sixty to ninety percent of obese subjects show histological abnormalities of the liver. The hepatic lesion can be classified into one of the four following groups: steatosis, steatohepatitis, fibrosis and cirrhosis. The incidence of cirrhosis among patients with fatty liver changes ranges from 1.5% to 8%. The now abandoned surgery procedures performed for the treatment of morbid obesity (jejunoileal bypass) had left a negative experience: the onset of acute hepatic failure in subjects with no previous hepatic disease or the development of cirrhosis within one year of the bypass. Very low formula diets leading to precipitous weight loss in morbidly obese people induce metabolic changes similar to those observed after jejunoileal bypass. We report the case of a morbidly obese patient who had lost 40 kg of weight during the 6 months previous to his hospitalization. He came with signs of hepatic failure. He worsened rapidly and died in a month-time. The hepatic tissue obtained post-mortem showed a non alcoholic steatohepatitic cirrhosis.

Adult↗
PubMed1997

[Hemochromatosis associated with hereditary spherocytosis].

Hereditary spherocytosis is a chronic hemolytic anemia that very infrequently produces severe iron overload. Only 15 cases of hereditary spherocytosis associated with hemochromatosis have been described previously. It was initially thought that hemochromatosis was the result of the increase of iron stores secondary to chronic hemolysis. Afterwards, it became apparent that iron overload could appear in patients splenectomized. This fact suggested that spherocytosis and idiopathic hemochromatosis could be inherited independently. We describe the case of a 45-year-old man, with known hereditary spherocytosis, splenectomized at 5 years of age, who developed iron overload which affected his heart, liver and pancreas.

Cardiomyopathies↗
PubMed1993

Detection and comparison of DNA adducts after in vitro and in vivo diesel emission exposures.

Development of methods to evaluate certain classes of polycyclic aromatic compounds (PAC) detected in complex mixtures to which humans are exposed would greatly improve the diagnostic potential of 32P-postlabeling analysis. Identification of DNA adduct patterns or specific exposure-related marker adducts would strengthen associations between observed DNA adducts and exposures to different environmental pollutants (e.g., kerosene, cigarette smoke, coke oven, and diesel). We have compared diesel-modified DNA adduct patterns in various in vitro and in vivo rodent model systems and compared them to DNA reactive oxidative and reductive metabolites of 1-nitropyrene. The formation of nitrated polycyclic aromatic hydrocarbon (nitrated PAH) DNA adducts, derived from the metabolism of diesel extract constituents, was enhanced relative to other PAH-derived DNA adducts via xanthine oxidase-catalyzed nitroreduction. These adducts were detectable only by the butanol extraction version of the postlabeling analysis. Five major DNA adducts were detected in human lymphocytes treated in vitro with diesel extract. A major adduct detected in human lymphocytes treated in vitro with diesel extract comigrated with a major adduct detected in lymphocyte DNA treated with benzo[a]pyrene (BaP) alone. Other adducts that co-migrated with the major BaP-derived adducts were detected in skin and lung DNA isolated from rodents topically treated with (50 mg) diesel extract and the major adduct detected in calf thymus DNA treated with rat liver S9 and diesel particle extract. Postlabeling of lung DNA isolated from rodents exposed via lung inhalation for 24 months to diesel combustion emissions resulted in the formation of a major nuclease-P1-sensitive DNA adduct that did not co-migrate with the major BaP-diol epoxide adduct.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

1-Chloromethylpyrene: a reference skin sensitizer and genotoxin.

1-Chloromethylpyrene (1-CMP) has been evaluated as a model mutagen and toxin related to the ultimate electrophiles derived from benzo[a]pyrene and 1-nitropyrene. It was mutagenic to Salmonella (greater than 100 pg/plate) and exceptionally reactive to DNA when assessed by the 32P-postlabelling technique. 1-CMP was inactive in a mouse bone micronucleus assay when administered by gavage, probably due to hydrolysis, whose kinetics have been studied (t1/2 approximately 23 min at 37 degrees C). However, as expected, it was a potent skin toxin as determined by its activity as a mitogen to mouse skin and its contact allergenicity, as determined using the local lymph node proliferative assay. It is concluded that 1-CMP will probably be a potent human skin carcinogen and contact allergen.

Animals↗
PubMed1988

Mutagenic screening of marker grenade dyes by the Salmonella reversion assay, L5178Y/TK+/- mouse lymphoma assay, and in vivo sister chromatid exchange analysis in mice.

Two dyes (C.I. Solvent Yellow No. 33 and a mixture of C.I. Solvent Yellow No. 33 and C.I. Solvent Green No. 3) were tested for mutagenicity in the Salmonella reversion assay and the L5178Y/TK+/- mouse lymphoma assay, and also for sister chromatid exchange (SCE) induction in vivo in C57B1/6J mice. In addition, a greater than 99.9% pure sample of the yellow dye [2-(2'-quinolyl)-1,3-indandione] was tested with and without exogenous activation in the Salmonella reversion assay and the L5178Y/TK+/- mouse lymphoma assay. Neither C.I. Solvent Yellow No. 33 nor the C.I. Solvent Yellow No. 33 and Solvent Green No. 3 mixture was positive for inducing SCEs in vivo. All three dyes were tested in the standard plate incorporation test in seven Salmonella strains TA98, TA100, TA102, TA104, TA1535, TA1537, and TA1538. The dyes were negative with and without exogenous activation in TA98, TA1535, and TA1538. One test with TA1537 was positive with the greater than 99.9% purified yellow dye. All three dyes gave weakly positive results (less than a twofold increase) with S-9 in TA100 and were clearly positive in TA102 and TA104 both with and without S-9. They also induced mutation at the thymidine kinase locus in mouse lymphoma cells, produced both large- and small-colony trifluorothymidine-resistant mutants, and were clastogenic. The purified yellow dye was further tested for SCE induction in mouse lymphoma cells and was determined to give a slightly positive response in the presence of S-9.

Animals↗
PubMed1983

Mutagenicity of diesel-exhaust particle extract, 1-nitropyrene, and 2,7-dinitrofluorenone in Salmonella typhimurium under various metabolic activation conditions.

The mutagenic activities of 1-nitropyrene (1-NP), 2,7-dinitrofluorenone (2,7-DNF), and a diesel-exhaust extract were compared using the Salmonella typhimurium plate-incorporation assay. Each sample was tested with and without a 9000 X g liver homogenate (S9), both with and without an NADPH-generating system. The samples were also treated with the microsome fraction of S9, cytosol fraction of S9, boiled S9, bovine serum albumin (BSA), and boiled BSA. Salmonella tester strains TA98 and TA98FR1 were used in all treatments; TA98/1,8DNP6 was used to test mutagenic activity without activation. Without the NADPH-generating system, the samples generally had less mutagenic activity than samples treated with the NADPH-generating system. The addition of the NADPH-generating system resulted in marked increases in mutagenic activity of 1-NP in the microsome and S9 treatments, and of all 3 samples in the cytosol fraction treatment. These results indicate that although protein binding reduced the mutagenic activity of diesel-exhaust extract and 1-NP, microsomal activation increased the mutagenic activity of 1-NP. Because 1-NP and 2,7-DNF contributed less than 1.5% of the mutagenic activity of the diesel-exhaust extract, the response to diesel exhaust was not typified by these compounds.

Animals↗
PubMed1980

Pulmonary nonspecific defense mechanisms in cystic fibrosis. I. Phagocytic capacity of alveolar macrophages and neutrophils.

Cystic fibrosis (CF) is the commonest cause of chronic obstruction lung disease within the first three decades of life. Because patients suffer from repeated pulmonary infections, we were interested in studying the nonspecific antibacterial mechanisms of the lungs of CF children. Fifteen CF children, 13 nontuberculous pulmonary-infected (I) children and 4 noninfected (N-I) children, who were diagnosed as having a foreign body in the air passages, were submitted to a bronchopulmonary washing. The absolute number, viability, and differential count of the cells were determined, and the phagocytic assay using the Lehrer's technique was carried out on the harvested cells. The materials obtained from CF and I patients were mucopurulent, whereas the ones from the N-I patients were not mucopurulent. The number of cells retrieved from CF and I patients was higher than that from the N-I patients. This was attributed to an increase in the absolute number of polymorphonuclear leukocytes. The phagocytic capacity of polymorphonuclear leukocytes was not different for the three groups studied, whereas that of alveolar macrophages was higher for the CF and the I patients than for the N-I ones. Inasmuch as there was no significant difference between the CF and the I patients, we conclude that the nonspecific phagocytic behavior of alveolar macrophages and pulmonary polymorphonuclear leukocytes of CF patients might be similar to the one coming from other bacterial infectious states of the lung.

Adolescent↗