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Biomedical subjects

R M Mulligan

Publications and source records attributed to R M Mulligan.

40 records · Page 3Linked to original sources
PubMedDate not supplied

RNA editing site recognition in higher plant mitochondria.

RNA editing is a process by which genomically encoded cytidines are converted to uridines in plant mitochondrial transcripts. This conversion usually changes the amino acid specified by a codon and converts an "aberrant" residue to the evolutionarily conserved amino acid. The selection of the edited cytidine is highly specific. The cis-acting sequences for editing site recognition have been examined in ribosomal protein S12 (rps12) transcripts and in transcripts for a second copy of an internal portion of the ribosomal protein S12 (rps12b). rps12b was created by recombination at 7 and 9 nucleotide sequences that included editing sites I and IV of rps12, thus affording an opportunity to study the editing of chimeric transcripts with rearrangement very near C to U editing sites. Rearrangements downstream of editing site IV did not affect the editing of that sequence, while rearrangement upstream of editing site I ablated editing at that cytidine residue. Secondary structure predictions indicated that RNA structure did not correlate with the editing of these substrates. These results taken together with other studies in the literature suggest that RNA editing site recognition is primarily dependent on the 5' flanking RNA sequence.

Amino Acid Sequence↗
PubMedDate not supplied

Etiologic factors in carcinoma of the prostate.

A staining method is presented by which azocarmine combines with spermine to form a poorly soluble red precipitate highlighted against the yellow cytoplasm of positive cells achieved by counterstaining with metanil yellow. In the prostate, the spermine-dye complex was abundant in normal acinar epithelial cells, moderate in the epithelial cells of hyperplastic glands, and moderate to absent in carcinoma cells. Spermine is evidently concerned with stabilizing the structure of desoxyribose nucleic acid and probably of proteins, notably several zinc metalloenzymes. Diagnosis and treatment of carcinoma of the prostate should include an adequate basic diet, retention of testes, hormonal treatment oriented toward testicular, pituitary and hypothalamic hormones; zinc--ordinary and radioactive; and utilization of spermine and precursors.

Adenocarcinoma↗
PubMedDate not supplied

Neural cells in culture.

In vitro culture of neural cells (nerve sheath cells, melanoblasts, neuroblasts, astrocytes) for three to 20 months revealed a non-mitotic type of replication characterized by appearance between 30 and 120 days. Unipolar and bipolar neural cells, resulting from an initial phase of mitotic reproduction, developed multipolar and dendritic forms with large cell bodies and numerous primary and secondary processes with broad proximal ends exhibiting right-handed helices by phase contrast, differential interference electron microscopy and time lapse cinemicrophotography. The nuclei of the conspicuous cell bodies were quite large, one to three, and contained round, rod, ovid or comma nucleoli up to three or four per nucleus. After 30 days of culture, the nuclei of the cell bodies were notably quiescent with regard to mitotic proliferation, but nucleoli were active and mitochondria were numerous around the nuclei. The cytoplasm of the cell bodies often contained channels interpreted as cisternae of endoplasmic reticulum. The helices of the processes were interpreted as cytoplasmic pumps for conveying mitochondria into their distal ends. The slender distal ends became packed with rod and filamentous mitochondria, which then broke up into fine granules associated with the formation of new nuclei appearing in the preterminal and terminal ends of the processes. The preterminal or terminal unit--knob containing nucleus and distal end of process packed with mitochondrial dust--detached by was of a thread-like connection as a new cell, which entered into a new growth phase toward non-mitotic proliferation.

Adult↗