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Biomedical subjects

M Sussman

Publications and source records attributed to M Sussman.

At least 91 records · Page 5Linked to original sources
PubMed1970

RNA in cytoplasmic and nuclear fractions of cellular slime mold amebas.

A method is described for the rapid separation of cellular slime mold (Dictyostelium discoideum) cells into nuclear and cytoplasmic fractions. Sucrose density sedimentation profiles of radioactivity from cells that had been grown for long or short periods in the presence of uridine-(3)H indicate very low levels of cross-contamination between the fractions. The nuclear fraction contains few, if any, ribosomes. In exponentially growing cells, at least 80% of the ribosomes were associated in polysomal complexes. No loss of counts from pre-labeled rRNA was observed during 2 generations (24 hr) of logarithmic growth and, within the polysomal complexes, the distributions of the preformed material and of rRNA synthesized during the 2 generations were identical. In stationary phase cells that had entered the developmental program leading to fruiting body construction, the rRNA turned over rapidly so that by the end of development at least 75% of the ribosomes fabricated during exponential growth had disappeared and had been replaced by new ones synthesized during the morphogenetic sequence. The preformed ribosomes disappeared preferentially from the monosomal contingent; the newly synthesized ribosomes appeared exclusively in the polysomal contingent and did not appear as monosomes in appreciable numbers for at least 6 hr. The possible significance of this wholesale replacement of ribosomes is discussed.

Amino Acids↗
PubMed1969

Asymptomatic significant bacteriuria in the non-pregnant woman. I. Description of a population.

The clinical, laboratory, and radiological findings in a group of 107 non-pregnant bacteriuric women and 88 controls have been compared. A previous history of urinary tract infection was more commonly obtained from the bacteriuric women. The means of the diastolic blood pressures, serum ureas, and erythrocyte sedimentation rates were significantly higher in the bacteriuric group, and acquired renal abnormalities were demonstrated in 18% of the bacteriuric women as compared with 4% of the controls. It is concluded that screening for asymptomatic bacteriuria in the adult non-pregnant female population in many instances fails to detect urinary tract infection at an early and reversible stage.

Adult↗
PubMed1969

Asymptomatic significant bacteriuria in the non-pregnant woman. II. Response to treatment and follow-up.

Short courses of nitrofurantoin and ampicillin produced an immediate cure in 80% of adult non-pregnant bacteriuric women. Of the subjects so treated, 55% remained cured at the end of one year. Over the same follow-up period 36% of untreated bacteriuric women developed a spontaneous remission of bacteriuria. Treatment failed to prevent the development of symptomatic infection, and the reinfections which followed successful treatment were more commonly associated with the development of symptoms than the persistent or relapsing infections in untreated or unsuccessfully treated subjects.It is concluded that a search for bacteriuria in non-pregnant women is unlikely to be of value as a preventive measure, since in many instances it fails to detect urinary tract infection at an early stage and since treatment by methods suitable for large-scale use is ineffective.

Adult↗
PubMed1969

Alternative developmental pathways determined by environmental conditions in the cellular slime mold Dictyostelium discoideum.

The cellular slime mold Dictyostelium discoideum grows in the soil as a population of independent, uninucleate amoebae. Upon entrance to the stationary phase, the amoebae collect in multicellular aggregates to form organized fruiting bodies composed of spores and stalk cells. Depending upon environmental conditions, the developing aggregate either constructs the fruiting body at the site of aggregation or transforms into a structure that can migrate to a more favorable location. Environmental conditions that favor migration are (i) the accumulation of metabolite(s) produced by the aggregate and (ii) a low ionic strength in the substratum. Conditions that prevent migration or that stop a migrating slug are (i) the presence of buffer and (ii) illumination by overhead light.

Amoeba↗