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Biomedical subjects

J C Crawley

Publications and source records attributed to J C Crawley.

At least 37 records · Page 2Linked to original sources
PubMed1984

Assessment of left ventricular function in coronary artery disease with the nuclear probe during intervention studies.

The nuclear probe was used for measuring left ventricular function in 11 normal subjects and the results compared with those using a digital gammacamera. The probe was then used to measure left ventricular function in patients with coronary artery disease during dynamic exercise and stress atrial pacing. The ability of the probe to detect changes induced by glyceryl trinitrate was also evaluated in separate parallel studies. In the 11 normal subjects there was a good correlation between the left ventricular ejection fraction measured by the gammacamera and the nuclear probe both at rest and during exercise. Exercise increased this value by at least 5% in all normal subjects during measurements with both the gammacamera and the nuclear probe. The mean (SD) difference was -0.3% (2.60) at rest and 2.3% (5.02) at peak exercise. Both exercise and pacing produced angina in the patient group and the mean (SEM) value fell from 52% (3.5) to 28% (2.6) and from 46% (5.1) to 34% (3.2) respectively. Glyceryl trinitrate prolonged the exercise and pacing times, and the corresponding falls in ejection fraction were significantly reduced. The non-imaging nuclear probe is a cheap and portable instrument capable of assessing left ventricular function in patients with cardiac disease. It is designed for high count rate acquisition over a short period of time and can thus provide both beat to beat and summated left ventricular time activity curves suitable for quantitative analysis. It therefore has important advantages in the clinical setting and during controlled interventions compared with the gammacameras.

Adult↗
PubMed1983

Thyroid function and immunological activity during and after medical treatment of Graves' disease.

The variable clinical course of Graves' disease has been followed in 27 patients each studied for 2 years from the time of diagnosis. Thyroid hormone synthesis was blocked with large doses of antithyroid drugs for the first 12 months while euthyroidism was maintained with triiodothyronine. The latter was given alone from 12 to 18 months, and for the last 6 months the patients received no treatment. The activity of the disease was determined by repeated measurements of thyroid uptake of pertechnetate and by assay of thyrotrophin receptor antibodies (TSH binding inhibitory immunoglobulins). Retrospectively there were no features on presentation which singly or in combination indicated the clinical outcome: 16 patients remained in remission (Group 1) whilst in 11 hyperthyroidism had recurred before the end of the study (Group 2). Both measures of disease activity (thyroid uptake and antibody levels) fell during the first 12 months in patients of both groups. Recurrence of Graves' disease could be predicted in some but not all patients of Group 2 at 12 months by higher thyroid uptakes and levels of thyrotrophin receptor antibodies. There was, however, evidence of abnormal thyroid function, from which we infer continuing activity of the disease, 12 to 18 months after diagnosis in all patients of Group 1, even though these patients had normal TRH tests during the last phase of the study. The difference in the course of Graves' disease 12 to 24 months after diagnosis between those patients who remained in remission and those who did not was relative: in no patient was completely normal physiological control of thyroid function re-established. Clinical remission from hyperthyroidism at this time is a level of disease activity at which the normal physiological output of thyroid hormones is not exceeded.

Carbimazole↗
PubMed1983

Consistency and variability in the character of thyrotrophin receptor antibodies in Graves' disease.

At diagnosis there was no correlation between the uptake of pertechnetate by the thyroid and thyrotrophin receptor antibodies (TRAb) measured as TSH binding inhibitory immunoglobulins in a series of 27 patients with Graves' disease. TRAb were detectable initially in 19 patients, in 11 of these there was a significant positive correlation (P less than 0.05) between serial measurements of pertechnetate uptake and TRAb made during 2 years following diagnosis. In five patients pertechnetate uptake fell with time whilst TRAb levels were maintained or fluctuated. In the remaining three of the 19 patients both measurements were low and did not change during treatment. We conclude that TRAb in any individual patient are a mixture of immunoglobulins of variable effectiveness as thyroid stimulators. In a majority of patients the composition of this mixture remains constant during the course of the illness and the clinical state reflects the levels of TRAb in the blood. In a minority, however, the character of these antibodies may alter with time or there is a change in the responsiveness of the thyroid gland. The general lack of correlation between measurements of thyroid stimulating activity and TSH binding inhibitory immunoglobulins in groups of patients is due to differences between patients in the composition of TRAb.

Female↗
PubMed1983

Scalp blood flow measured by the xenon clearance technique and transcutaneous PO2 in the fetal lamb.

Scalp blood flow and transcutaneous (tc) PO2 were measured in four fetal lambs at 130-135 days of gestation. Scalp blood flow was measured by the xenon clearance technique using a technetium source to correct for changes in distance from the detector. The effect of circular pressure, the so-called "tonsure effect" on scalp flow and tcPO2, was evaluated by pressing a ring on the scalp. A circular pressure between 20-30 mmHg markedly reduced local scalp blood flow and was sufficient to reduce tcPO2 to zero. We found evidence of significant recirculation of xenon in the fetal circulation indicating right-left shunting. This study showed that the tonsure effect seriously affected scalp blood flow and tcPO2 in the fetus.

Animals↗
PubMed1982

Selenium 75-selenofolate metabolism and radiation dosimetry.

Following the oral administration of 75Se-selenofolate in two normal healthy volunteers, retention was measured by whole body counting, and distribution throughout the body was determined with a hybrid scanner. Approximately 65% of the dose was absorbed from the GI tract. The metabolic data obtained from this study was used to calculate the integrated radiation dose to the liver, and the effective dose equivalent.

Absorption↗
PubMed1982

Graves' disease: thyroid function and immunologic activity.

Patients with Graves' disease were studied for two years during and after a twelve-month course of treatment. Disease activity was determined by repeated measurements of thyroidal uptake of [99mTc]pertechnetate during tri-iodothyronine administration. These in-vivo measurements of thyroid stimulation were compared with the results of in-vitro assays of Graves, immunoglobulin (TSH binding inhibitory activity--TBIA). There was no correlation between the thyroid uptake and TBIA on diagnosis. Pertechnetate uptake and TBIA both declined during the twelve months of antithyroid therapy. TBIA was detectable in sera from 19 of the 27 patients at diagnosis; in 11 of these 19 patients there was a good correlation (p less than 0.05) throughout the course of their disease between the laboratory assay of the Graves, immunoglobulin and the thyroid uptake. Probability of recurrence can be assessed but sustained remission of Graves' disease after treatment cannot be predicted from either measurement alone or in combination.

Adult↗
PubMed1981

Feasibility of outpatient management after intra-articular yttrium-90: comparison of two regimens.

In a study comparing two regimens of treatment after intra-articular irradiation of the knee with yttrium-90 one group of patients was allocated to bed rest for 48 hours in hospital and the other to mobilisation at home. Initially a Robert-Jones orthopaedic bandage was applied to the knee in all patients, serving as a semi-rigid splint, but as loss of isotope from the knee was appreciable in the mobilised patients, subsequent patients were sent home with the knee in a plaster-of-Paris cylinder. No difference in extra-articular spread or chromosomal damage was found between the patients sent home with their knee in a rigid splint and those treated by bed rest. Clinical outcome at three months was satisfactory in all three groups. These results show that rigid splinting is essential in reducing extra-articular spread of the isotope but that bed rest is not necessary. Increases in intra-articular pressure associated with quadriceps muscle activity combined with flexion of the knee may be the most important factor affecting extra-articular spread of isotope.

Ambulatory Care↗
PubMed1980

Increased alveolar epithelial permeability in cigarette smokers.

Two indices of alveolar epithelial permeability were derived in man by a non-invasive method. The rate of transfer of 99mTc DTPA (diethylenetriamine penta-acetate) from the lung into the blood was measured and a significantly greater (P less than 0.001) transfer rate was found in symptomless cigarette smokers compared with non-smokers.

Adult↗
PubMed1980

The measurement of gastric transit time in obese subjects using 24Na and the effects of energy content and guar gum on gastric emptying and satiety.

1. A new method has been used to measure mean gastric transit time. 2. This method, based on the absorption of 24Na from the proximal small bowel, is simple, non-invasive and can be used at the bedside. 3. The mean transit time was increased by adding guar gum to a test meal. 4. There was a significant correlation between mean gastric emptying time and a subjective measure of satiety.

Adult↗
PubMed1979

Evaluation of two regimens to immobilise the knee after injections of yttrium-90.

Two regimens to immobilise the knee after injection were compared in patients receiving intra-articular yttrium-90 for persistent synovitis of the knee, the patients being randomly allocated to receive either complete bed rest or full mobilisation with the affected knee in a firm splint. There was no difference in the percentage of the radioisotope retained in the knee or in that taken up by other tissues between the two regimens. It is concluded that after intra-articular injections of yttrium-90 strict bed rest in hospital is unnecessary.

Bed Rest↗
PubMed1979

Placental intervillous blood flow measured by inhaled 133Xe clearance in relation to induction of epidural analgesia.

A method of determining placental intervillous blood flow (IBF) using an inhaled 133Xe technique is described. The method was used to investigate the effect on IBF of epidural analgesia with an initial dose of 37.5 mg bupivacaine. There was no statistically significant reduction in IBF following the initial dose of bupivacaine in spite of a small but statistically significant reduction in mean blood pressure. There was no significant correlation between the change in mean blood pressure and the percentage change in IBF following epidural block although the single largest percentage reduction in IBF was associated with the largest fall in mean blood pressure.

Adult↗
PubMed1978

Abnormalities of renal transport of sodium o-[131I]iodohippurate (Hippuran) in essential hypertension.

1. Renal function has been studied in 312 hypertensive patients by quantitative renography with sodium o-[131I]iodohippurate (131I-labelled Hippuran) and estimation of overall effective renal plasma flow. In 59% of the patients the results were normal. 2. Severe hypertension was associated not only with reduced effective renal plasma flow but also a characteristic abnormality of Hippuran transport in 10% of the patients in which there was a wider than normal variation in transit times of Hippuran through the kidney, which may reflect non-uniformity of reabsorption of filtrate by different groups of nephrons. 3. Plasma renin activity was higher in a group of 14 patients with multimodal transit time spectra than in a matched hypertensive control group, with very substantial overlap between the two groups. 4. The renographic abnormality was usually reversed by treatment.

Blood Flow Velocity↗
PubMed1977

Treatment of Gaucher's disease with liposome-entrapped glucocerebroside: beta-glucosidase.

An adult with Gaucher's disease was injected with liposomes containing human glucocerebroside: beta-glucosidase. After 13 months of treatment the lower border of the right hepatic lobe and moved up 3 cm, and the left lobe had shrunk. Reduction in the size of the liver was associated with relief of pressure symptoms in the left lower abdomen. Scans obtained after the injection of radiolabelled liposomes suggested improvement in function of the reticuloendothelial system.

Adult↗