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Biomedical subjects

E Israeli

Publications and source records attributed to E Israeli.

At least 55 records · Page 3Linked to original sources
PubMed1991

Inhibition of growth of Bacillus subtilis by recombinant plasmid pCED3.

The present study deals with the mechanism by which plasmid pCED3 interferes with the growth of Bacillus subtilis. Plasmid pCED3 was constructed from pUB110 and pBR322 and contains the lacZ gene attached to the B. subtilis tms promoter. Plasmid derivatives that contain mutations in the tms promoter were used to examine the effect of promoter strength on cell growth, plasmid stability, the amount of plasmid DNA per cell and the activities of plasmid-encoded enzymes, i.e., beta-galactosidase and kanamycin nucleotidyltransferase (KNT). Efficient lacZ transcription directed from the tms promoter resulted in reduction in growth rate and plasmid stability without an increase in beta-galactosidase activity. The amount of plasmid DNA varied between 6.6 and 12.9 pmol per mg cell protein and showed no clear correlation with the strength of the tms promoter. Transcription from the tms promoter inhibited the expression of the plasmid-encoded kanamycin resistance gene resulting in the reduction of both beta-galactosidase activity and growth rate in the presence of kanamycin. These results suggest that the negative effect on B. subtilis growth exerted by pCED3 results at least partly from a decrease in kanamycin resistance by plasmid-bearing cells.

Bacillus subtilis↗
PubMed1988

Biological safety cabinets, decontamination or sterilization with paraformaldehyde.

Bacillus subtilis var. niger spores were used to determine the exposure time for formaldehyde decontamination of biological safety cabinets. Formaldehyde contact times less than 3 hr were insufficient for sterilization. A contact time of 4 hr or more resulted in a reproducible killing of the spore strips placed inside the cabinets. At 6 hr sufficient formaldehyde had diffused through the high efficiency particulate air (HEPA) filter to sterilize the strips with lower spore counts. A minimum of 5 to 6 logs of killing were observed after 4 to 6 hr of treatment.

Bacillus subtilis↗
PubMed1985

Cyclic nucleotide levels in human breast cancer and in rat mammary tissues during tumor development.

The levels of cyclic adenosine 3':5'-monophosphate (cAMP) and cyclic guanosine 3':5'-monophosphate (cGMP) were studied in dimethylbenz(a)anthracene (DMBA)-induced mammary tumors of Sprague-Dawley rats and in human breast cancer. In the rat carcinomas, these levels were significantly lower than in non-malignant tissues when calculated on the basis of DNA content, but higher (cAMP) or equal (cGMP) when calculated on the basis of weight. In human breast cancer the cyclic nucleotide levels were higher than in non-malignant tissues according to both methods of calculation. No correlation was found in human carcinomas between the cyclic nucleotide levels and mitotic index, nuclear grade, tumor size, or lymph node involvement. The rat tumors were subclassified according to state of differentiation, mitotic index, and state of development. Not all the sub-groups had cAMP levels different from normal values. Differences in cAMP levels between the sub-groups could not be correlated with tumor growth rates and/or mitotic index. Thus, cyclic nucleotides may not be useful in prognosis of breast cancer.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

The development of time concepts in young children: the relations between duration and succession.

108 children from nursery school, first grade, and third grade were given 5 problems measuring the concept of time, in which they were required to judge and explain which of 2 partially overlapping events started first, which ended first, and which lasted for a longer time. 2 types of problems were used which presented time with and without the interference of movement: "still time" (the duration of 2 lights) and "linear time" (the traveling time of 2 toy cars). In both types of problems, judging the succession of both beginnings and endings was equally difficult and was easier than judging duration. Duration judgments were explaned predominantly by succession, whereas succession judgments were explained tautologically or by mere "seeing." Overall, performance increased with age and decreased with interference. A recent model of the development of time concepts is further elaborated and compared with Piaget's framework.

Child↗
PubMed1977

RNA:DNA ratios in human tumors.

A study has been made of the quantitative relation existing between the RNA:DNA ratios in benign and in malignant human tumors. It has been demonstrated that a significant difference (Student's t-test) existed between malignant and benign human tumors within the different groups studied: a) malignant and benign breast tumors (t=2.22, P less than 0.05); b) Hodgkin's disease in spleen and its controls (t=2.39, P less than 0.02); and c) malignant and benign thyroid tumors (t=4.23, P less than 0.01). The diagnostic value of this finding is discussed.

Breast Neoplasms↗
PubMed1977

Different binding sites for entry and exit of amino acids in whole cells of Mycobacterium phlei.

On the basis of mutual inhibition of uptake with different amino acids in whole cells of Mycobacterium phlei, it was demonstrated that the binding site of proline was different from those of all other amino acids studied. Other groups of amino acids share a common binding site: lysine, histidine, and arginine; valine, leucine, and isoleucine; tryptophan, tyrosine, and phenylalanine; glutamic acid and aspartic acid. The exit and entry processes were studied for proline, glutamine, and glutamic acid. It was observed that in each case the entry and exit processes were mediated by different membrane sites.

Amino Acids↗
PubMed1975

RNA:DNA ratios in a developing fibrosarcoma and its lung metastases in C3H mice.

The quantitative ratios of RNA:DNA were followed in a developing transplanted fibrosarcoma in C3H mice and in its lung metastases. There was a significant increase in these ratios in developing tumors originating from cell suspensions (P smaller than 0.001) and a single implanted piece (P smaller than 0.05). No significant change was demonstrated in developing fibrosarcoma originating from two pieces of this tumor (P greater than 0.05) which were implanted simultaneously. When comparing the ratios of RNA and DNA of developing lung metastases to the primary tumors, we found a significantly higher ratio in the metastases (P smaller than 0.001). No significant changes in RNA:DNA ratios were demonstrated in normal proliferating tissues either in physiologic hyperplasia or embryo tissue culture (P greater than 0.05).

Animals↗
PubMed1975

A human adrenocortical adenoma in tissue culture. Morphology and hormone secretion.

A human adrenocortical adenoma was cultivated in vitro and the morphological characteristics, steroidogenic activity and response to ACTH of the cultured cells were studied over a period of about two months. At first, the morphology of the cultures was similar to that of the original tissue. This structure changed in the course of time and the cells underwent fibroblastoid transformation. Stimulation with ACTH evoked two types of morphological response: a) a short-term response, whereby an extensive but rapidly reversible vacuolization was followed by cell enlargement and granulation, and b) a long-term effect in which the differentiated cell morphology was maintained. The cultures showed a low steroidogenic activity throughout the experiment. ACTH stimulation increased the total 17-hydroxysteroid production up to 10-fold. After ACTH withdrawal the corticosteroid levels declined slowly and about 50% of the maximal activity persisted on the fifth day after ACTH withdrawal.

Adenoma↗