Search PubMed⌕ Search

Biomedical subjects

L Graves

Publications and source records attributed to L Graves.

32 records · Page 2Linked to original sources
PubMed1989

Increase in the activity of tryptophan hydroxylase from cortex and midbrain of male Fischer 344 rats in response to acute or repeated sound stress.

Exposure of male Fischer 344 rats to an acute sound stress consisting of 100 dB tones of 2-s duration presented at random 60-s intervals for 2 h, increased cortical and midbrain tryptophan hydroxylase activity, measured in vitro, 50% over that from sham-stressed animals. This increase in enzyme activity was observed when animals were killed immediately, but not 1 h, after termination of the sound stress. It was non-additive with the increase in activity induced by incubation of enzyme under phosphorylating conditions and could be reversed in vitro with alkaline phosphatase. Graded increases in enzyme activity were obtained with increments of sound intensity (90-120 dB). In contrast to acute stress, chronic sound stress (110 dB) repeated over a period of 1, 2 or 6 weeks (3 sessions per week each of 2-h duration) produced a 50% increase in cortical enzyme activity that persisted 24 h after the termination of the stress and was not reversed by alkaline phosphatase. However, a further increase in enzyme activity could be produced if the chronically stressed animals were exposed to an acute 2-h stress (110 dB) immediately before being killed. This additional increase in activity was reversible in vitro by alkaline phosphatase and non-additive with that produced by incubation under phosphorylating conditions. In summary, acute sound stress produced a prompt, reversible activation of tryptophan hydroxylase. Repeated exposure to sound stress induced a persistent increase in enzyme activity that was detected 24 h after the last stress.

Acoustic Stimulation↗
PubMed1986

Behavioural differences of school-age children who were small-for-dates babies.

Twenty-one children aged between five and nine years who were small for gestational age (SFD) at birth and whose intra-uterine head growth was shown by ultrasonography to be slowing before 35 weeks were observed in a special room, using video-cameras. Their behaviour was compared with that of 21 matched control children who had had normal birthweight. The children in the SFD group were quieter, more compliant and less active than the control group, and their play behaviour suggested that they were less advanced developmentally. The behaviour of the mothers of the SFD group showed that they were aware of their child's problems and tried to compensate for it by teaching the child while they were waiting for the observational session to start, by sitting closer to the child during a drawing test, and by using more words to explain it.

Body Height↗
PubMed1982

Antigenic and genetic characterization of a novel hemagglutinin subtype of influenza A viruses from gulls.

Influenza A virus isolates from ring-billed, Franklin, blackback, and herring gulls in the United States possess a hemagglutinin (HA) distinct from the 12 reference HA subtypes. Serological assays (hemagglutination inhibition and double-immunodiffusion) with specific antisera to reference strains and to a representative gull isolate showed that the HA of the gull virus was not antigenically related to that of any known subtype. The gull virus did not replicate in ducks or chickens but did replicate in ferrets. Comparison of the nucleotide sequences (and deduced amino acid sequences) of the 3' 20% of the HA genes of these viruses indicates that the gull viruses represent a genetically distinct group. We propose that this HA, which has been detected only in gull isolates thus far, be called the H13 subtype.

Animals↗
PubMed1981

Electronic measurement of locomotion by means of pressure-sensitive floor mats.

This paper describes a method of adapting an observation room to record a child's position in the room and to give an index of the amount of locomotion. The adaptation consisted of under-carpet pressure mats, linked electronically to digital counters. This recording system showed a highly significant correlation with observational measurements of the same aspects of behaviour. It has potential as an aid in the diagnosis of abnormal behaviour states.

Child↗
PubMed1980

Fluoride resistance and adherence of selected strains of Streptococcus mutans to smooth surfaces after exposure to fluoride.

The fluoride resistance and smooth surface adherence characteristics of Streptococcus mutans were examined using tooth model and radioactive cell assays. Resistance to 600 ppmF by S. mutans isolated from the plaque of radiation-induced xerostomia patients receiving daily topical applications of a caries preventive 1% NaF gel was transient. Resistance induced in vitro in two strains of S. mutans by exposure to gradually increasing levels of NaF was apparently permanent. Smooth surface adherence by both fluoride-sensitive and -resistant strains of S. mutans 6715 in a tooth model system was slightly diminished by 1% NaF gel. Fluoride-resistant strains retained 89 to 93% of their adherence capability in 600 ppmF, as determined by the cell radiolabeling assay.

Adhesiveness↗
PubMed1979

Maturity of fetal lungs tested by production of stable microbubbles in amniotic fluid.

Lung surfactant in amniotic fluid, and hence the maturity of the fetal lungs, can be assessed by observation of stable microbubbles (less than 15 micron diameter). Bubbles are formed by agitation with a Pasteur pipette and examined in hanging drops under the 10 x power of a microscope. Either after a count of bubbles, or after a general survey of hanging drops, the fluid is given a stable microbubble rating. A 'strong' rating indicates that the idiopathic respiratory distress syndrome will not occur after delivery, and that the lecithin/sphingomyelin ratio will indicate maturity. Complete absence of stable microbubbles suggests a high risk of respiratory trouble for the newborn infant, as does a weak or lower rating in the 30 to 37 week gestational age group. The test takes 5 to 10 minutes to perform, is cheap and easy, is not affected by blood, but may be affected by meconium. If a 'strong' rating is found, measurement of the L/S ratio can safely be omitted.

Amniotic Fluid↗
PubMed1979

Mode of delivery and the lecithin/sphingomyelin ratio.

Babies born by elective Caesarean section are more likely to develop the respiratory distress syndrome that babies born vaginally. We studied the amniotic fluid and pharyngeal lecithin/sphingomyelin (L/S) ratios in three groups of babies born at term: 20 were delivered vaginally after elective induction of labour; 20 were delivered by elective Caesarean section; and 14 by Caesarean section after spontaneous onset of labour. Babies born after induction of labour had higher pharyngeal L/S ratios than babies born by elective Caesarean section. Those born by Caesarean section after spontaneous onset of labour had significantly higher pharyngeal L/S ratios than those in both of the elective delivery groups. There were no significant differences in the amniotic fluid L/S ratios of the two groups who underwent elective delivery. Regression analysis showed a significant relationship between length of labour and increase in the L/S ratio. These results indicate that, during labour, there is a release of fetal lung surfactant into the airways.

Amniotic Fluid↗
PubMed1976

Free cortisol in obesity; effect of fasting.

Plasma and urinary corticosteroids were measured in 13 obese subjects before and after high and low protein diets, and after fasting. During isocaloric high and low protein diets, urinary 17-oxogenic steroids and to a lesser extent urinary free cortisol excretion rose and fell in parallel with protein intake. Plasma unbound cortisol levels were not much changed by high or low protein intake. However, during 7 to 11 days total fasting, there was a highly significant rise in plasma unbound cortisol at 24.00. A smaller rise occurred at 09.00. The overall effect was a considerable diminution of the day-night variation of plasma unbound coritsol levels during fasting, and a rise in prevailing unbound cortisol levels and urinary free cortisol excretion. In 3 subjects tested these changes were reversed immediately by glucose re-feeding.

17-Ketosteroids↗
PubMedDate not supplied

Retention of neonatal resuscitation skills and knowledge: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: This study compared the effectiveness of two booster strategies designed to improve retention of skills and knowledge in neonatal resuscitation by family practice residents. METHODS: Residents were randomly allocated to one of three groups: video, hands on, or control. Residents in the two experimental groups received a "booster" 3-5 months after the Neonatal Resuscitation Program (NRP) course. All participants completed the follow-up test 6-8 months after taking the course. The main outcome measures consisted of the NRP written examination and the performance checklists. RESULTS: A total of 44 residents completed the study (video, n = 13; hands-on, n = 14; control, n = 17). Overall, participants had significantly lower scores at follow-up than at baseline, indicating deterioration in both neonatal skills and knowledge. Residents in the hands-on booster group made significantly fewer errors across all five checklists in life-supporting but not in lifesaving scores than those allocated to the control and video groups. CONCLUSIONS: The beneficial effect of mannequin practice or video boosters on skills and knowledge retention was less than what had been anticipated, and no benefit could be demonstrated in comparison to the control group. Deteriorating knowledge and skills remain a major concern, since boostering by hands-on or video at 3-5 months do not seem to have an impact on the retention of knowledge or lifesaving skills.

Adult↗
PubMedDate not supplied

Evaluation of Pepscan analyses for epitope mapping of anti-MUC1 monoclonal antibodies--a comparative study and review of five antibodies.

Many murine monoclonal antibodies against MUC1 mucin have been analysed for reactivity against short overlapping peptides with sequences based upon that of the 20 amino acid tandem repeat of the MUC1 protein core, in order to identify the minimum binding units or epitopes. This report summarises the findings using a set of overlapping heptamers to identify the epitopes of 5 established anti-MUC1 antibodies. The results are evaluated and reviewed in comparison to those obtained using other length peptides and other assay formats for epitope mapping using the Pepscan technique.

Amino Acid Sequence↗