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Biomedical subjects

R E Allen

Publications and source records attributed to R E Allen.

At least 91 records · Page 5Linked to original sources
PubMed1982

Influence of age on accumulation of alpha-actin in satellite-cell-derived myotubes in vitro.

Because muscle satellite cells have been implicated in the process of muscle growth and mass regulation, as well as regeneration, alterations in the capacity of satellite cells to differentiate and accumulate muscle specific proteins during aging could play a role in the process of senile muscle atrophy. Skeletal muscle satellite cells were cultured from male rats from the following four age groups: neonatal rats (less than 5 days of age), growing rats (1--3 months of age, adult rats (9--12 months of age) and old rats (more than 24 months of age). A series of experiments was conducted in which cultures were harvested at daily intervals following fusion, and the amount of alpha-actin per myotube nucleus was determined. Analysis of maximum actin accumulation in myotubes from each experiment within each age group revealed no significant differences among cells derived from growing, adult or old rats; however, myotubes differentiating from neonatal muscle cells were able to accumulate more than three times as much alpha-actin per myotube nuclei as cells from the other three age groups. This result may reflect fundamental differences between authentic satellite cells and myogenic cells of prenatal origin. Aside from differences between neonatal cells and satellite cells, satellite cells from old muscle do not appear to have a diminished capacity to accumulate muscle-specific proteins following differentiation into muscle fibers.

Actins↗
PubMed1982

The effects of child maltreatment on language development.

The separate effects of child neglect, abuse, and their interaction upon language development as measured by the Preschool Language Scale were examined in four groups of children (n = 79) in a quasi-experimental design. There were three groups of maltreated subjects, all drawn from a treatment center: an abused only group (n = 13), a neglected only group (n = 7), and an abused and neglected group (n = 31); a non-maltreated group (n = 28) was drawn from a day care center. Abuse, neglect, and their interaction were used to predict both auditory comprehension and verbal ability as separate criteria in two stepwise multiple regression equations, where the variance attributable to gender and mother's status on Aid to Dependent Children had been removed. Child neglect was found to predict significantly both auditory comprehension and verbal ability. Neither child abuse nor the interaction between abuse and neglect significantly predicted either dependent variable. These findings suggest that child neglect may be the critical type of maltreatment associated with language delay.

Child↗
PubMed1981

Occupational intoxication and long-term persistence of phencyclidine (PCP) in law enforcement personnel.

By utilizing a glass capillary gas chromatographic nitrogen detector (GC2-N) method specific for phencyclidine (PCP) and sensitive to pg/mL in blood or urine samples, we have demonstrated occupational intoxication of law enforcement personnel charged with handling confiscated illegal PCP preparations. Further, we have demonstrated persistence of PCP in blood and urine for at least 6 months after the last known occupational exposure in one officer. Some aspects of the PCP problem are outlined, and possible mechanisms of the occupational intoxication are discussed.

Adult↗
PubMed1980

Myogenic potential of satellite cells in skeletal muscle of old rats. A brief note.

Muscle satellite cells from old (> 30 months) female Long-Evans rats were isolated and grown in cell culture. Satellite cells differentiated in culture to form multinucleated myotubes that had the ability to accumulate muscle-specific proteins. Therefore, satellite cells exist in muscle through senescence and retain their myogenic potential.

Aging↗
PubMed1980

Drug modification of ECT: methohexital and diazepam. II.

A systematic comparison of methohexital and diazepam as anesthetics in the drug modification of ECT was done by holding atropinizaton, succinylcholine-depolarizing neuromuscular blockade, and resuscitation constant while monitoring four ECT in each of 24 patients. Each patient served as his own control, and two dosages of each drug (0.25 and 0.35 mg/kg diazepam, 0.9 and 1.1 mg/kg methohexital) were given each patient in all possible orderings (4! = 24) in a scheduled experimental design in which methohexital was given by very rapid (5 sec) and diazepam was given by the recommended slower (60 sec) infusion. The data revealed significant differences and methohexital was superior. Eight of 48 (17%) EKGs were abnormal post-ECT with methohexital, 18 of 48 (38%, phi = 5.3, p < 0.025) with diazepam. Five of 24 (21%) patients had an abnormal post-ECT EKG with methohexital, 15 of 24 (60%, phi 8.6, p < 0.005) with diazepam. Significantly more ventricular premature contractions (VPCs) occurred after diazepam. Diazepam records contained both more numerous and more extensive EKG abnormalities. Methohexital induction was clinically superior as well; there was little of the induction restlessness seen in seven treatments with diazepam (phi2 7.6, p < 0.01). The differences were less marked than in a previous study in which diazepam was given as rapidly as methohexital. Methohexital has been demonstrated to be the anexthesia of safety and choice for ECT when compared to diazepam.

Diazepam↗
PubMed1980

Incidental intoxication with phencyclidine.

Utilizing a sensitive and specific gas chromatography nitrogen detector (GC2-N) method we have demonstrated phencyclidine (PCP) in the blood of a 65-year-old widowed Mexican-American woman who lived in a second floor apartment directly over an illegal laboratory utilizing open-vat methods of PCP synthesis. This is the first proof of such incidental PCP intoxication, although police officers regularly complain of developing symptoms of intoxication after raiding such clandestine laboratories and handling the confiscated products. The presumed mechanism of incidental intoxication with PCP and the psychiatric manifestations of this patient are described and discussed.

Chromatography, Gas↗
PubMed1980

Disproportionate accumulation of myosin and tropomyosin in cultured muscle cells.

Accumulation of two major myofibrillar proteins, myosin and tropomyosin, was monitored in differentiating skeletal muscle cultures. The tropomyosin subunit to myosin heavy chain accumulation rate ratio was more than twice the stoichiometric ratio of tropomyosin subunit to myosin heavy chain in mature skeletal muscle myofibrils and crude myofibrils from cultured muscle cells. Electron microscopy revealed normal patterns of myofibril assembly in these muscle cultures. Therefore, the observed disproportionate accumulation of tropomyosin and myosin heavy chain may be reflecting normal cellular conditions for de novo myofbril assembly.

Animals↗
PubMed1978

Sythesis of tropomyosin in cultures of differentiating muscle cells.

The accumulation of tropomyosin in cultures of differentiating muscle cells was quantitatively measured. Tropomyosin was isolated from cultured cells during and after myoblast fusion; both alpha- and beta-subunits were present in myotube cultures. During fusion small amounts of tropomyosin were detectable, but, as fusion approached a maximum, tropomyosin accumulation began to increase. The increased synthesis of tropomyosin after the initiation of muscle cell fusion is consistent with the increased synthesis of other proteins characteristic of muscle, including myosin.

Animals↗