PubMed Health⌕ Search

Biomedical subjects

C Perry

Publications and source records attributed to C Perry.

At least 91 records · Page 5Linked to original sources
PubMed1989

Interactions of Escherichia coli SO-187 tRNA(IVal) with Bacillus stearothermophilus valine-tRNA synthetase studied by 13C-NMR.

Uracil isotopically labelled with 13C at C4 and C5 has been incorporated into nucleic acids of the Escherichia coli uracil auxotroph, SO-187. [4,5-13C]uracil-labeled tRNA(IVal) was isolated and purified. 13C longitudinal relaxation times measured at 67.8 MHz demonstrated that the C5 dipole caused a 20-50% increase in the C4 relaxation. Interactions of this tRNA with valine-tRNA synthetase (VTS) purified from Bacillus stearothermophilus were established by 13C-NMR. Specific spectral changes were seen at 4-thiouridine, ribothymidine and pseudouridine of the 'bend' in the three-dimensional structure, and particularly at the uridine-5-oxyacetic acid in the wobble position of the anticodon. Thus, the protein seems to be in contact along the entire tRNA molecule, including the anticodon loop.

Amino Acyl-tRNA Synthetases↗
PubMed1989

In vivo [31P]NMR studies on the influence of age on rat brain hypoxia.

In this paper the response of cerebral phosphate metabolism to mild hypoxia in young, medium and old rats has been studied via in-vivo [31P]nuclear magnetic resonance (NMR). It was found that the young adults (5-6 months) were more sensitive to this mild stress than either the mature adult (11-12 months) or senescent (23-24 months) rats even though the depth of hypoxia (paO2 = 45-55 mm Hg) was equal for all age groups. They displayed an earlier onset of acidosis, a greater fall in PCr and larger rise in Pi. This response is presumably an attempt to maintain adequate adenosine triphosphate (ATP) levels via anaerobic glycolysis. In contrast, mature adults and senescent adults appear to be able to maintain ATP levels by increasing mitochondrial rates. Acidosis is less severe as are drops in PCr and rises in Pi. Recovery is less complete for the young rats: Pi levels remain high while PCr and pHi levels stay low after normoxia has been reinstigated. All metabolite levels in the mature and senescent adults return to within 10% of control levels. All the data were analyzed and differences were found to be statistically significant. This study reveals that, contrary to popular belief, mature and old rats respond more favorably to reduced O2 than younger individuals. This is due to a more severe anaerobic acidosis in the latter age group. Speculations to explain this disparity are based on the fact that previous in-vitro studies involve systems that are totally or partially disconnected from the organism will not account for important feedback control present in an in-vivo system as studied here.

Aging↗
PubMed1988

Preservation of the eye in paranasal sinus cancer surgery.

Forty-one patients undergoing surgery between 1977 and 1985 for malignant tumors of the paranasal sinuses abutting or eroding the orbital walls were studied for the need to remove the orbital contents. All patients had preliminary computed tomographic scans to delineate the extent of orbital invasion. All were treated with preoperative radiotherapy. If the tumor mass could be peeled from the periorbita, the eye was saved. Preservation of eyes in the patients without periosteal invasion did not alter survival. Frozen-section control may be used to determine periorbital involvement. If the periorbita was minimally involved, it was locally resected. If invasion of the periorbita was extensive, an orbital exenteration was done. Only five of 41 patients required exenteration. Local recurrence of disease in the orbit has not occurred in these patients.

Adenocarcinoma↗
PubMed1987

Total glossectomy.

Total glossectomy is a procedure based on sound oncologic principles, and its usefulness may not be fully appreciated. Given the dimensions of the tongue and the need to obtain a wide margin of resection, this procedure may be indicated in selected T3 lesions and recurrences after irradiation. The procedure offers excellent palliation of pain, and form and function may be preserved by rim mandibulectomy when indicated. New reconstructive techniques allow for speedier recovery. Aspiration need not be a complication of total glossectomy if care is taken to preserve the superior laryngeal nerve. Speech rehabilitation plays an important role in returning these patients to their normal environment. Overall 1 and 3 year disease-free survival rates have been encouraging.

Adolescent↗
PubMed1987

Multiple predictors of hypnotic susceptibility.

In this article, we report two experiments in which various measures thought to be related to hypnotizability were analyzed by stepwise discriminant analysis techniques. Absorption (Tellegen, 1981, 1982; Tellegen & Atkinson, 1974) and preference for an imagic style of thinking (Isaacs, 1982) were robust predictors of hypnotizability; each variable accounted for significant variance in hypnotizability at their respective steps in two samples and correctly classified a significant proportion of low- and high-hypnotizable subjects in the discriminant analyses. The addition of two other variables in Experiment 2--a Sleep-Dream score derived from Evans's (1977) Cognitive Control of Sleep Mentation subscale and Gibson's (1985) Dream Questionnaire, and the Belief in the Supernatural subscale of the Taft (1969) Experience Questionnaire--increased the correct classification of the medium-hypnotizable subjects from chance levels to 74%. It is argued that a confirmatory and hierarchical approach is needed in future studies to explore correlates of hypnotizability more fully.

Adult↗
PubMed1986

Flicker electroretinogram in retinitis pigmentosa.

Electroretinograms (ERGs) were recorded as a function of flicker frequency from 5 to 50 Hz for 14 retinitis pigmentosa (RP) patients, 12 normal subjects and 1 rod monochromat. Data were analyzed by measuring the angular position of the response maximum, i.e. the phase, as a function of pulse-train frequency. Flicker ERGs obtained from the RP patients showed non-linear, frequency-dependent phase shifts when compared to the normal data. These phase shifts were simulated in a normal observer by attenuating the stimulus luminance by 1 log unit. However, the shape of the waveforms recorded from the normal differed markedly from those recorded from the RP patients. The differences, but not the ratios of the times-to-peak of the positive and negative ERG wavelets were longer in the RP patients than in the normal. These data suggest that the temporal anomalies in the RP flicker ERG are most likely due to changes in the amplitudes and time constants of the ERG components, and not simply to a reduced quantum catch or photoreceptor loss.

Adolescent↗
PubMed1986

Transient visual anomalies associated with drug treatment for spastic colon.

A case report revealing two previously unreported adverse side effects of meprobamate and tridihexethyl chloride (Milpath) drug therapy for a spastic colon is presented. The two previously unreported adverse effects are a diffuse loss of color discrimination and an increased time course to complete dark adaptation.

Colonic Diseases, Functional↗
PubMed1985

A problem with refusing certain forms of psychiatric treatment.

Certain affective disorders are associated with compromised cognitive and emotional capacities and thus, with one's ability to act as a fully autonomous individual. Some of these personality problems have been treated very successfully with specified drug regimes. Continued treatment with lithium has rendered previously incompetent manic patients fully capable of competent self-governance. If the competent have the right to refuse medical attention (even when the refusal is not in the patient's best interest) does the drug-induced competent psychiatric patient have the right to refuse that medical treatment necessary for his continued competency? This paper investigates this issue.

Beneficence↗