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Biomedical subjects

A Segal

Publications and source records attributed to A Segal.

At least 145 records · Page 8Linked to original sources
PubMed1983

Acute myelomonocytic leukemia associated with nephrotic syndrome. A case report with immunological studies.

A patient with acute myelomonocytic leukemia (AML) developed nephrotic syndrome. The renal biopsy showed focal glomerulosclerosis by light microscopy. Electron microscopy and immunofluorescence revealed electrondense deposits, IgG and C'3 in the glomerular mesangium. A 21S circulating immune complex (CIC) present in the patient's serum and the renal biopsy eluate contained immunochemically identical materials. The isolated antibodies from the 21S CIC and the eluate showed restricted reactivity against autologous AML cells. Immunodiffusion studies demonstrated common antigenicity between the 21S CIC antigen, the eluted antigen and between autologous AML cell membrane antigens.

Antigen-Antibody Complex↗
PubMed1983

Hormonal and cytopathological changes in vaginal and cervical smears from women undergoing chemotherapy for extragenital malignant diseases.

The effects of various chemotherapeutic drugs on the squamous epithelium of the cervicovaginal tissues were investigated in a test group of 74 and a control group of 44 women with advanced extragenital malignancy. The cytological findings were as follows: (A) cytohormonal changes reflecting estrogenic withdrawal in pre- and postmenopausal women, (B) reversible cytopathological changes reflecting a cytotoxic reaction, and (C) absence of premalignant and malignant changes.

Adult↗
PubMed1983

Bacterial colonization of the nose and external ear canal in newborn infants.

The bacterial flora of the nose and external ear canal of 132 newborn infants, aged 3 days and 4 to 7 days, was examined. Cultures taken from the nose showed the following pattern of bacterial colonization: normal flora (39%); potentially pathologic gram-positive microorganisms (23%); gram-negative enteric rods (16%); and sterile cultures (22%). The most frequent bacterial cultures from nostrils were Staphylococcus epidermidis (39%); Staph. aureus (11%) and Escherichia coli (8%). The cultures from the external ear canal showed normal flora (37%); potentially pathologic gram-positive microorganisms (5%); gram-negative enteric rods (24%); and sterile cultures (34%). The most frequent bacteria cultured from the ear canal were: Staph. epidermidis (37%); E. coli (8%); and Klebsiella pneumoniae (7.5%). Of several factors studied, the type of delivery, Apgar score and the duration of hospitalization were found to have a significant influence on the pattern of bacterial colonization.

Apgar Score↗
PubMed1982

Formation of 6-dimethylcarbamyloxy-dGuo, 6-dimethylamino-dGuo and 4-dimethylamino-dThd following in vitro reaction of dimethylcarbamyl chloride with calf thymus DNA and 6-diethylcarbamyloxy-dGuo following in vitro reaction of diethylcarbamyl chloride with calf thymus DNA.

The rodent carcinogens dimethylcarbamyl chloride (DMCC) and diethylcarbamyl chloride (DECC) react with dGuo (pH 7.0-7.5, 37 degrees C, 4 h) to form the O6-acyl derivatives 6-dimethylcarbamyloxy-2'-deoxyguanosine (6-DMC-dGuo) and 6-diethylcarbamyloxy-2'-deoxyguanosine (6-DEC-dGuo), respectively. Reaction of DMCC with dThd under identical conditions yielded 4-dimethylamino-thymidine (4-DMA-dThd). Compounds 6-DMC-dGuo and 6-DEC-dGuo undergo a nucleophilic aromatic substitution reaction with dimethylamine (DMA) to form 6-dimethylamino-2'-deoxyguanosine (6-DMA-dGuo) via displacement of the C-6 dialkylcarbamyloxy moiety. The substitution reaction did not take place when diethylamine or NH3 were substituted for DMA. The structures of the new compounds 6-DMC-dGuo, 6-DEC-dGuo, 4-DMA-dThd and 6-DMA-dGuo were deduced from chemical analyses and syntheses, UV and nuclear magnetic resonance (NMR) spectra and electron impact, isobutane chemical ionization and source insertion isobutane chemical ionization mass spectra. It was postulated that 4-DMA-dThd was formed following reaction of the transient intermediate 4-DMC-dThd with DMA formed by hydrolysis of DMCC. Calf thymus DNA was reacted in vitro with DMCC (pH 7.0-7.5, 37 degrees C, 4 h) and the modified DNA hydrolyzed enzymatically to 2'-deoxynucleosides. Compounds 6-DMC-dGuo, 4-DMA-dThd and 6-DMA-dGuo were identified in the hydrolysate by high-pressure liquid chromatography (HPLC). In an identical manner 6-DEC-dGuo was identified following in vitro reaction of DECC with calf thymus DNA. Compounds 6-DEC-dGuo and 6-DMC-dGuo possess novel structures with respect to the types of adducts known to be formed between carcinogens and bases in DNA. The implications of these findings with respect to chemical mutagenesis and carcinogenesis is discussed. The structural relationship between N4-dimethyl-5-methylcytosine (4-dimethylamino-Thy) formed in DNA following in vitro reaction with DMCC and 5-methylcytosine, the only modified base found in vertebrate DNA is noted.

Animals↗
PubMed1982

Effect of patient size on doses received by patients in diagnostic radiology.

A large number of people in this country receive X-rays every year. It would be of value to determine the dose received by an individual, and to follow the medical histories of each. However, it is shown that with currently available information, it is not possible to determine with sufficient accuracy the dose received by an individual exposed to diagnostic X-rays. Therefore, this step in establishing a dose-response relationship is more imprecise than it need be. A suggestion is made on using the exposure-area product to overcome this difficulty.

Adult↗
PubMed1982

[Not Available].

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Equipment and Supplies↗
PubMed1981

The isolation and characterization of 3-(2-carboxyethyl)cytosine following in vitro reaction of beta-propiolactone with calf thymus DNA.

The new adduct 3-(2-carboxyethyl)cytosine (3-CEC) was isolated following in vitro reaction of the carcinogen beta-propiolactone (BPL) with calf thymus DNA. The structure of 3-CEC was confirmed by synthesis from BPL and dCyd. Reaction of BPL with cCyd (pH 7.0-7.5, 37 degrees C) gave 3-(2-carboxyethyl)deoxycytidine (3-CEdCyd) (9% yield) and 3,N4-bis(2-carboxyethyl)deoxycytidine (3,N4-BCEdCyd) (0.6% yield). 3-CEdCyd and 3,N4-BCEdCyd were hydrolyzed (1.5 N HCl, 100 degrees C, 2 h) to 3-CEC and 3,N4-bis(2-carboxyethyl)cytosine (3,N4-BCEC), respectively. The structure of 3-CEC was assigned on the basis of UV and NMR spectra and the electron impact (EI) mass spectra of 3-CEC and a tri-trimethylsilyl (TMS) derivative of 3 CEC as well as deuterated (d27) tri-TMS derivative of 3-CEC. The structure of 3,N4-BCEC was assigned on the basis of UV spectra and the EI mass spectra of a tri-TMS derivative. Ei and isobutane chemical ionization mass spectra of 3-methylcytosine (3-MeCyt) and a di-TMs derivative of 3-MeCyt were obtained and were helpful in deducing the structures of 3-CEC and 3,N4-BCEC. This is the first report of the alkylation by BPL of an exocyclic atom on a base in DNA. Compound 3,N4-BCEC was not detected in BPL-reacted calf thymus DNA. The relative amounts of 1-(2-carboxyethyl)-adenine (1-CEA), 7-(2-carboxyethyl)guanine (7-CEG), 3-(2-carboxyethyl)-thymine (3-CET) and 3-CEC isolated from BPL-reacted DNA following perchloric acid hydrolysis were 0.23, 1.00, 0.39 and 0.41 respectively, when the alkylation reaction was conducted in phosphate buffer at 0-5 degrees C and pH 7.5 and 0.10, 1.00, 0.29 and 0.28 respectively when the reaction was conducted in H2O at 37b degrees C and pH 7.0-7.5.

Animals↗
PubMed1981

[Not Available].

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Education, Medical↗