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Biomedical subjects

C Eastman

Publications and source records attributed to C Eastman.

14 recordsLinked to original sources
PubMed1999

Coordinated transcriptional regulation of the unc-25 glutamic acid decarboxylase and the unc-47 GABA vesicular transporter by the Caenorhabditis elegans UNC-30 homeodomain protein.

An important aspect of the specification of neuronal fate is the choice of neurotransmitter. In Caenorhabditis elegans the neurotransmitter GABA is synthesized by the UNC-25 glutamic acid decarboxylase (GAD) and packaged into synaptic vesicles by the UNC-47 transporter. Both unc-25 and unc-47 are expressed in 26 GABAergic neurons of five different types. Previously, we have identified that the unc-30 homeobox gene controls the fate of 19 type D GABAergic neurons. We report here that the UNC-30 homeodomain protein transcriptionally regulates the expression of unc-25 and unc-47 in the 19 type D neurons. UNC-30 bound to the unc-25 and unc-47 promoters sequence-specifically. Mutations in the UNC-30 binding sites of the unc-25 and unc-47 promoters abolished the expression of reporter genes in the D neurons. The ectopic expression of UNC-30 induced the ectopic expression of reporter genes driven by the wild-type unc-25 and unc-47 promoters. Our data establish a mechanism for cell type-specific transcriptional coregulation of genes required for the synthesis and packaging of the neurotransmitter GABA.

Animals↗
PubMed1994

The quantitative distribution of nebulized antibiotic in the lung in cystic fibrosis.

Nebulized antibiotic therapy in cystic fibrosis is an established procedure. The present study was designed to quantitate deposition, and assess its relation to the disease state. Twenty seven children and young adults with cystic fibrosis (mean 11.6 years, range 4-23 years, 12 females) were studied to establish the quantity and pattern of deposition of nebulized tobramycin in the respiratory tract. A single (120 mg) dose of nebulized 99 m technetium-labelled tobramycin was administered, and imaged with a gamma-camera. The mean penetration index (which compares the distribution of 81 m-Krypton gas with Tc-radioaerosol) was also used to measure peripheral deposition efficiency. The aerosol mass median diameter (MMAD) for the compressor-nebulizer system used was 5.3 u, measured with the Malvern Mastersizer. Serial sputum samples were fluroimmunoassayed for tobramycin in nine patients. A mean of 8.0 (SEM 1.0) mg tobramycin reached the lungs. There was no relationship between the total pulmonary deposition and indices of pulmonary damage in cystic fibrosis. Sixteen percent of the lung tobramycin reached the periphery. The greater the lung damage as indicated by FEV1 and Chrispin-Norman scores, the smaller the proportion of pulmonary tobramycin that reached the periphery. The mean penetration index increased with increase in the FRC, but bore no relation to other respiratory function tests or to chest X-ray scores. Sputum tobramycin concentrations reached levels bactericidal for Pseudomonas aeruginosa. Airway obstruction and damage affected the proportion of pulmonary tobramycin reaching the periphery. The proportion of tobramycin reaching the lungs was small and variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Evaluation of automated urinary iodine methods: problems of interfering substances identified.

We evaluated automated methods for measurement of urinary iodine (UI) over a range expected in iodine-replete and iodine-deficient populations. Results obtained with Technicon AutoAnalyzer II systems, based on either dialysis or acid digestion, were compared with those obtained by a manual alkaline ashing technique. Results of automated dialysis were consistently higher than those obtained by the other methods. The apparently higher concentrations of UI we measured were due to interfering substances crossing the dialysis membrane and participating in the catalytic reaction. Thiocyanate (SCN) was one endogenous substance contributing to the increased measurement of UI. For urinary SCN concentrations of 5 to 15 mg/L, the amount of overestimation in the UI measurement attributable to SCN ranged from 21.8 to 61 micrograms/L. However, SCN may account for only 40-50% of the apparent increase in UI. In samples with lower UI (less than 50 micrograms/L), interfering substances produced a 100% error in results. We conclude that the automated dialysis system should not be used to assess iodine-deficient populations. This leaves a major dilemma for researchers wanting to assess the iodine status of populations, because the automated digestion method is no longer commercially available.

Adult↗
PubMed1988

Antibodies to the period gene product of Drosophila reveal diverse tissue distribution and rhythmic changes in the visual system.

Polyclonal antibodies were prepared against the period gene product, which influences biological rhythms in D. melanogaster, by using small synthetic peptides from the per sequence as immunogens. The peptide that elicited the best antibody reagent was a small domain near the site of the pers (short period) mutation. Specific immunohistochemical staining was detected in a variety of tissue types: the embryonic CNS; a few cell bodies in the central brain of pupae; these and other cells in the central brain of adults, as well as imaginal cells in the eyes, optic lobes, and the gut. The intensity of per-specific staining in the visual system was found to oscillate, defining a free-running circadian rhythm with a peak in the middle of the night.

Animals↗
PubMed1986

Effects of stress inoculation training on self-report, behavioural and psychophysiological reactions to abseiling.

The study examined the effect of stress inoculation training on the level of self-reported stress and anxiety, overt signs of distress and the physiological impact of the stress of abseiling. Twenty volunteer subjects were randomly assigned to either a 'no training' control group or a stress inoculation training group, following which both groups of subjects had to complete a test abseil from the roof of a 21.2 m building. Prior to descent, two self-report measures were taken: an intensity score derived from the word or phrase chosen by subjects from the Perceived Stress Index to best describe their feelings and a state anxiety score from Spielberger's State Trait Anxiety Inventory. Overt distress was also evaluated by a 'blind' observer also using the Perceived Stress Index. In addition, heart rate was monitored just prior to and throughout the abseil using a telemetry system. The stress inoculation group showed significantly less self-reported anxiety and stress and less behavioural signs of distress as judged by the observer. However, there were no significant differences between the groups in terms of heart rate. In addition, while self-report and the assessment of the observer were highly inter-correlated, these measures were poorly correlated with heart rate.

Adolescent↗
PubMed1986

Stress inoculation training: a case study in gymnastics.

A young female gymnast of regional squad potential had ceased to make progress when she resumed training after a series of injuries and was given stress inoculation training to help her to regain her form. Preliminary interviews revealed that she had developed a number of negative self-statements and images which, it was hypothesised, may have been contributing towards her lack of progress. In order to replace these with positive self-statements and images a treatment programme of eight training sessions was implemented. Recorded interviews and subsequent comparison of comments made by the subject before and after the intervention programme, indicated that the training had been successful. This was endorsed by the coaches who reported an improved attitude to training and rapid progress in skill learning.

Child↗
PubMed1986

Binding characteristics of thyroxin binding globulin in serum of normal, pregnant, and severely ill euthyroid patients.

Serum from normal, pregnant, and severely ill patients was stripped of endogenous thyroid hormones and diluted 1100-fold in barbital buffer. We then used it to study the binding characteristics of thyroxin binding globulin (TBG), noting significant differences in binding capacities among the groups. The mean (+/- SD) triiodothyronine/thyroxin ratio for binding capacity was 18 +/- 4 for normal subjects. The ratio was significantly increased in pregnant patients, 21 +/- 4 (p less than 0.05), and significantly lower in severely ill patients, 12 +/- 4 (p less than 0.05). When serum was diluted before assay, to give a uniform TBG concentration among groups, these apparent differences in binding characteristics were eliminated. It therefore is unlikely that different molecular species of TBG account for the variations in binding characteristics in these clinical states. Apparently, the distribution of thyroxin and triiodothyronine among the binding sites on TBG changes with variations in TBG concentration. This may explain the discrepancies observed in the concentrations of free thyroid hormones as estimated by various methodologies.

Binding, Competitive↗
PubMed1983

Circadian temperature and wake rhythms of rats exposed to prolonged continuous illumination.

The purpose of this study was to simultaneously measure temperature and sleep in the rat under continuous illumination in an attempt to reveal properties of the underlying circadian oscillators. At first, the circadian rhythms of temperature and wake free-ran in parallel. Within weeks or months, circadian arrhythmicity developed in most animals. Both circadian rhythms eventually damped out, even at fairly low light intensities. The circadian rhythm of wake was weaker and disintegrated sooner than the circadian rhythm of temperature. Although the data did not rule out control by separate circadian oscillators, one for temperature and one for wake, a single oscillator model was sufficient to explain this phenomenon. Ultradian variations with a period of about 2-5 hr were superimposed upon the circadian rhythms. When the circadian rhythms damped out, the ultradian variations remained. The ultradian bursts of wake preceded the ultradian bursts of temperature, suggesting a causal relationship. On the other hand, the circadian rhythm of temperature could not be dependent on the circadian rhythm of wakefulness, because the temperature rhythm could persist while the wake rhythm was absent.

Animals↗
PubMed1982

As others see us: general practitioners' perceptions of psychological problems and the relevance of clinical psychology.

Structured interviews were carried out with 30 randomly selected general practitioners, to discover how they perceived and handled psychological problems in their patients. In addition, the doctors' perceptions and expectations of their professionals who might assist in the management of such problems were examined. Much of the previously published work was confirmed by the present investigation, but some new information was also uncovered. Thus, although almost all the GPs were sympathetic towards the wish of some clinical psychologists to work at the primary health care level, almost half the doctors would not want a psychologist within their practice, even if finance and accommodation were not problematic. Clinical psychologists were viewed, primarily, as therapists and, as such, were mostly expected to provide a regular part-time service to the practice. Only a minority of GPs wished to acquire skills from clinical psychology, but a large majority were in favour of direct referrals. The results of this study are discussed in terms of their implications for clinical psychology services.

Allied Health Personnel↗