PubMed Health⌕ Search

Biomedical subjects

P Sheldon

Publications and source records attributed to P Sheldon.

At least 55 records · Page 3Linked to original sources
PubMed1987

A comparison of a sustained release preparation of tiaprofenic acid with the conventional tablet formulation and a placebo in rheumatoid arthritis.

In a randomized double-blind, multicentre crossover study, the short-term efficacy and tolerance of tiaprofenic acid (TA) conventional tablet 300 mg twice daily was compared with a sustained release preparation of tiaprofenic acid 600 mg once daily and with a placebo in 146 patients with rheumatoid arthritis. After a minimum washout period of three days, patients were randomly allocated to receive each treatment for a period of two weeks each in a crossover fashion. Pain levels, duration of morning stiffness, onset of inactivity stiffness, articular index, and grip strength, were measured at the end of the washout period and at the end of each treatment period. Escape analgesic consumption, patient compliance, patient preference and overall assessment were measured at the end of each treatment period. Side-effects were noted and standard laboratory tests performed. Sustained release TA was shown to be as effective as the conventional tablet TA in the treatment of rheumatoid arthritis, producing significant improvements in efficacy parameters measured. Both preparations were as well tolerated as the placebo.

Adult↗
PubMed1986

Treatment of chronic knee effusions with 90yttrium-correlation of in vitro radiation and chemical effects with clinical results at three and six months.

Twenty seven knees, mainly of rheumatoid patients, received intra-articular 90Y for chronic effusions; 24% were effusion-free at 6 months. In vitro chemical, radiation (32P-induced), and combined effects of cold (non-radioactive) yttrium and 32P on synovial fluid mononuclear cells, failed to show any significant correlation with subjective and/or objective clinical effects at 3 or 6 months. If 90Y exerts its therapeutic effect via these cells, it probably does so other than by a direct effect on mononuclear cell viability.

Chronic Disease↗
PubMed1985

Magnetic resonance imaging the velocity vector components of fluid flow.

Encoding the precession phase angle of proton nuclei for Fourier analysis has produced accurate measurement of fluid velocity vector components by MRI. A pair of identical gradient pulses separated in time by exactly 1/2 TE, are used to linearly encode the phase of flow velocity vector components without changing the phase of stationary nuclei. Two-dimensional Fourier transformation of signals gave velocity density images of laminar flow in angled tubes which were in agreement with the laws of vector addition. These velocity profile images provide a quantitative method for the investigation of fluid dynamics and hemodynamics.

Fourier Analysis↗
PubMed1985

Specific cell-mediated responses to bacterial antigens and clinical correlations in reactive arthritis, Reiter's syndrome and ankylosing spondylitis.

In 2 cases of ReA seen during the acute phase and shown serologically to be due to Y. enterocolitica 0:3, the LT test showed a marked response using as antigen a freeze dried preparation of the causative organism. The test result correlated with the activity of the disease when repeated during a flare in the 1st case, and during remission in both. Patients with ReA/RS in general showed a significantly higher response to the yersinia and klebsiella antigens tested when compared to AS, suggesting an overall difference in cell-mediated immunity to these enteric bacteria. AS cases reacted significantly less than controls to K. pneumoniae under suboptimal conditions. K. pneumoniae was shown to enhance the LT response to yersinia, possibly through an adjuvant effect. This was found with AS, ReA and in controls, though whether it is of relevance in the etiopathogenesis of AS or ReA/RS remains far from clear. Acute non-traumatic synovitis of the knee, occurring de novo, or in association with psoriasis, inflammatory bowel disease, or as part of RS, may be accompanied by evidence of heightened reactivity to streptococci both by blood and synovial fluid mononuclear cells. In 1 case with serological evidence of streptococcal infection and erythema nodosum, these changes were found to parallel disease activity. ReA can, it appears, follow recent streptococcal infection, and be associated with B27.

Antigens, Bacterial↗
PubMed1985

A controlled trial of tiaprofenic acid against indomethacin in patients with rheumatoid arthritis.

A multicentre double-blind crossover study of tiaprofenic acid 600 mg daily against indomethacin 75 mg daily was carried out in 68 patients with rheumatoid arthritis to compare short-term efficacy and tolerance. There were no significant differences in efficacy between the two treatments, but significantly fewer C.N.S. side-effects were associated with tiaprofenic acid treatment. Five patients withdrew during the course of the study due to side-effects and all were receiving indomethacin.

Adult↗
PubMed1984

A method for the selective beta-irradiation of individual lymphocyte microcultures and its application in a preliminary study of radiation sensitivity.

A method that permits high energy beta-irradiation to be applied to individual lymphocyte microplate cultures is described. The principle involves the introduction of single energy sources (in this case 32P) contained within tubes which rest inside wells containing the lymphocyte cultures. Cell viability and mitogen-induced transformation were studied under these conditions. Dose-response effects were clearly demonstrated. The method is simple and, provided the precautions described are adhered to, safe. It should be applicable to studies of radiation sensitivity of putative target cells in various clinical situations.

Animals↗
PubMed1984

High-resolution magnetic resonance imaging. Technical concepts and their implementation.

In magnetic resonance (MR) imaging manipulating spatial resolution, contrast resolution, and imaging time separately results in improvement in some parameters without degradation of others. The authors have found that MR imaging of the head with a repetition time TR = 2.0 seconds produces images with high signal-to-noise levels and excellent sensitivity to demyelinating disease and brain water content. In the body, a long TR yields large signal levels that permit delineation of low-intensity structures such as patent vessels and bone. The long TR technique can be used in a high-resolution mode (256 X 256 data acquisition elements, each 0.8 X 0.8 mm) while maintaining image times of 50 or 100 sec/section. For normal resolution (1.7 X 1.7 mm), imaging time is 25 or 50 sec/section. It is concluded that the combination of slow-imaging techniques with simultaneous multisection imaging will prove practical for clinical MR.

Brain↗
PubMed1984

Nuclear magnetic resonance: principles of blood flow imaging.

Nuclear magnetic resonance (NMR) imaging with spin-echo techniques defines vascular structures with superb anatomic detail. Contrast agents are not necessary as there is intrinsic contrast between flowing blood and the vascular wall. The signal intensity from blood within the vessel lumen varies with the sequence of gradient and radiofrequency pulses used to generate the image as well as with the velocity of blood flow. Appropriate imaging techniques can optimize anatomic detail, distinguish slow from rapidly flowing blood, and serve to identify marked impairment or complete obstruction of flow in an artery or vein. Some examples of these principles in the intracranial circulation are illustrated.

Adolescent↗
PubMed1983

Nuclear magnetic resonance imaging of mammary adenocarcinomas in the rat.

A study of 24 rats implanted in the hind leg with mammary adenocarcinomas and five sham-implanted rats, followed from the second to the eight week postimplantation, showed nuclear magnetic resonance imaging capable of detecting all the tumors without yielding any false-positives in the control rats. The T1 relaxation time of tumors overlapped that of muscle, and the T2 times overlapped fat, but the combination was unique when comparing tumors to muscle and fat. Necrotic regions of the tumor and the bladder contents tended to have very long T1 and T2 relaxation times. The difference in relaxation time between tumors and muscle could be accounted for in terms of water content, which was approximately 8% higher for the tumors. The study corroborates data from previous studies indicating that NMR imaging is a highly sensitive modality, although T1 and T2 times are not exclusive indicators of malignancy.

Adenocarcinoma↗
PubMed1983

Nuclear magnetic resonance imaging of acute myocardial infarction in dogs: alterations in magnetic relaxation times.

Nuclear magnetic resonance (NMR) imaging was used to study 24-hour-old acute myocardial infarctions in 8 dogs. Images and measurements of excised hearts were obtained in a 6.5 ml bore-resistive NMR imager (0.35 Tesla). Spin echo NMR imaging in each instance demonstrated the area of infarction as a region of increased signal intensity compared with that in normal myocardium. The T1 and T2 values of the area of infarction were greater than those of normal myocardium in all dogs. For each dog the T1 value was greater for the infarct region; however, the group mean value for T1 (ms) of the infarct region (728 +/- 94) was not significantly greater than that for the normal region (650 +/- 87). The T2 value (ms) was discriminate for all dogs, and the mean value for the infarct region (48 +/- 2) was significantly different (p less than 0.01) from the value for normal myocardium (42 +/- 1). The percent water content of the infarct (79 +/- 1%) was significantly greater (p less than 0.01) than that of normal regions (76 +/- 1%). The linear relationship between T2 value and percent water content showed a good correlation coefficient (r = 0.90; p less than 0.01). NMR imaging detects acute myocardial infarction as a positive image without contrast media. Increased signal intensity of the infarct is related to increased hydrogen density and increased T2 relaxation time.

Animals↗
PubMed1983

Nuclear magnetic resonance imaging of the kidney.

The role of nuclear magnetic resonance (NMR) imaging of the kidney was analyzed in 18 persons (6 normal volunteers, 3 patients with pelvocaliectasis, 2 with peripelvic cysts, 1 with renal sinus lipomatosis, 3 with renal failure, 1 with glycogen storage disease, and 2 with polycystic kidney disease). Ultrasound and/or computed tomography (CT) studies were available for comparison in every case. In the normal kidney distinct anatomical structures were clearly differentiated by NMR. The best anatomical detail was obtained with spin echo (SE) imaging, using a pulse sequence interval of 1,000 msec and an echo delay time of 28 msec. However, in the evaluation of normal and pathological conditions, all four intensity images (SE 500/28, SE 500/56, SE 1,000/28, and SE 1,000/56) have to be analyzed. No definite advantage was found in using SE imaging with a pulse sequence interval of 1,500 msec. Inversion recovery imaging enhanced the differences between the cortex and medulla, but it had a low signal-to-noise level and, therefore, a suboptimal overall resolution. The advantages of NMR compared with CT and ultrasound are discussed, and it is concluded that NMR imaging will prove to be a useful modality in the evaluation of renal disease.

Glomerulonephritis↗
PubMed1983

Nuclear magnetic resonance imaging of the thorax.

Nuclear magnetic resonance (NMR) images of the thorax were obtained in ten normal volunteers, nine patients with advanced bronchogenic carcinoma, and three patients with benign thoracic abnormalities. In normal volunteers, mediastinal and hilar structures were seen with equal frequency on NMR images and computed tomographic scans. The hila were especially well displayed on spin-echo images. Spin-echo images showed mediastinal invasion by tumor, vascular and bronchial compression and invasion, and hilar and mediastinal adenopathy. Tumor and benign abnormalities could be separated from mediastinal and hilar fat because of their longer T1 times. Lung masses and nodules as small as 1.5 cm could be seen on the spin-echo images. NMR imaging shows promise for assessment of benign and malignant mediastinal, hilar, and lung abnormalities.

Adult↗
PubMed1983

The potential impact of nuclear magnetic resonance imaging on cardiovascular diagnosis.

Nuclear magnetic resonance (NMR) is used to generate cross-sectional images of the human body that show excellent anatomic and functional definition. The NMR imaging process involves interactions between electromagnetic fields and the hydrogen nuclei being imaged. These interactions occur on time scales of milliseconds to seconds. Consequently, the motion of these nuclei, for instance, when carried by blood, produces distinct signatures that are used to assess flow in major vessels. Myocardial dyskinesis also produces visible effects. Because of these effects, NMR imaging may be a safe and effective tool in the diagnosis and assessment of cardiovascular disease.

Blood Flow Velocity↗
PubMed1983

NMR demonstration of cerebral abnormalities: comparison with CT.

Sixty-eight patients with a wide spectrum of brain pathology were imaged with both computed tomography (CT) using a G.E. 8800 scanner and nuclear magnetic resonance (NMR) imaging with a 3.5 kG prototype device. NMR was more advantageous in the detection and/or characterization of pathology in 20 of the 68 patients, especially when demyelination was part of the disease process or when the lesion was obscured on CT by beam-hardening artifact. Punctate foci of calcification identified on CT were not detected on NMR, but larger calcifications were seen. NMR was sensitive to detection of both normal and abnormal vascular structures. The ability of NMR to differentiate among different pathologic entities remains to be fully evaluated. NMR currently complements CT in the evaluation of many disease entities and may actually supplant CT in some. The full future potential of NMR and its role with respect to CT has only begun to be elucidated.

Adolescent↗