Search PubMed⌕ Search

Biomedical subjects

M Graham

Publications and source records attributed to M Graham.

At least 91 records · Page 5Linked to original sources
PubMed1977

Ultrasound emission in infant rats as an indicant of arousal during appetitive learning and extinction.

Infant rats rewarded for crawling by being allowed to suckle on the dry nipple of an anesthetized dam showed a decreasing rate of ultrasound production during acquisition and an increasing rate during extinction. These results suggest that infant rats can be stressed and are aroused as a result of successive nonrewards just as adult rats are. In addition, these results do not support the hypothesis that infant rats lack inhibitory mechanisms related to poorly developed neural centers.

Animals↗
PubMed1975

Properties of sea urchin embryo messenger RNA containing and lacking poly(A).

Various properties of nonhistone messenger RNA species containing poly(A), [+A]mRNA, and lacking poly(A), [-A]mRNA, are described: the rates of turnover of these mRNA classes are not significantly different, as indicated by their similar rates of entry into and decay from the cytoplasm; each mRNA class is essentially entirely transcribed from unique DNA sequences; the ratio of [+A] to [-A] nonhistone mRNA increases with increase in size of free polyribosome, although the average molecular weights of these mRNAs are similar in each polysomal size class. These results indicate that the [+A]mRNA species tend to be more fully loaded with ribosomes than the nonhistone [-A]mRNA species.

Animals↗
PubMedDate not supplied

Double pituitary glands with partial duplication of facial and fore brain structures with hydrocephalus.

A female term infant was born with multiple bony and facial abnormalities involving the mandible, palate, tongue, nasopharynx, vertebrae, ribs and brain. Death occurred at 1 week and a rare combination of forebrain anomalies, were found in a big head, with complete agenesis of the corpus callosum with duplication of the infundibulum, pituitary, anterior third ventricle and aqueduct. The CAT scan was diagnostic of agenesis of corpus callosum. Incomplete twinning or incompetent neural induction with genetic and epigenetic factors have been suggested as possible mechanisms responsible for this rare malformation.

Abnormalities, Multiple↗
PubMedDate not supplied

Murine T lymphomas with retroviral inserts in the chromosomal 15 locus for plasmacytoma variant translocations.

The frequent trisomy of murine chromosome 15 in T lymphomas suggests that it bears one or more genes conducive to T-cell neoplasia. One such gene seems to be c-myc, the oncogene frequently activated in B-lymphoid tumours either by retroviral insertion, as in the avian bursal lymphomas, or by a translocation to the immunoglobulin heavy-chain locus, as in the predominant t(12; 15) of murine plasmacytomas and the analogous t(14; 8) of human Burkitt lymphomas. The c-myc gene was strongly implicated in T-cell neoplasia when 15-25% of T lymphomas arising in AKR mice, a strain prone to leukaemia, were found to have retroviral inserts near c-myc. Proviruses near c-myc were also found in several T lymphomas induced by murine leukaemia viruses (MuLV) in both mice and rats, but many of the rat thymomas bear an insert instead at one of several other common sites, at least two of which have murine homologues on chromosome 15. We show here that some murine T lymphomas contain proviral inserts in the recently identified chromosome 15 locus for plasmacytoma variant (6; 15) translocations, which we have denoted pvt-1. Although 6; 15 breakpoints map cytogenetically to the same chromosome band as c-myc, the alterations of pvt-1 in tumours occur at least 72 kilobases (kb) from the c-myc promoters. The insertions in T lymphomas suggest that an altered pvt-1 locus is conducive to neoplasia in T cells as well as B cells, possibly via long-range effects on c-myc expression.

Animals↗
PubMedDate not supplied

Disposition of cocaine in fatal poisoning in man.

A fatal case of intravenous (IV) cocaine administration is presented. Cocaine tissue concentrations (mg/kg) in descending order were: kidney, 26; spleen, 22; brain, 14; heart, 6.1; skeletal muscle, 6.1; lung, 3.4; liver, 1.6; and adipose, 1.0. Body fluid cocaine concentrations (mg/L) were: urine, 39; bile, 10; vitreous humor, 2.4; and blood, 1.8. These results are in excellent agreement with cocaine tissue distribution in the dog following IV administration and limited tissue data in previously reported cocaine fatalities in man.

Adult↗
PubMedDate not supplied

Tympanosclerosis. An electron microscopic study of matrix vesicles.

The ultrastructure of tympanosclerotic tissue has been studied and compared with other processes of fibrogenesis and calcification. Evidence is presented of the presence of large numbers of extracellular membrane-bound matrix vesicles and their role as the site of primary calcification in tympanosclerosis. Calcified spherular structures are formed and fuse into larger structures lined by a lamina limitans indicating the lines of arrested calcification in the collagenous matrix.

Adult↗