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M J Sands

Publications and source records attributed to M J Sands.

At least 19 recordsLinked to original sources
PubMed1990

Identification of a novel transforming growth factor-beta (TGF-beta 5) mRNA in Xenopus laevis.

A novel transforming growth factor-beta (TGF-beta) mRNA of about 3.0 kilobases, which encodes a putative protein of 382 amino acids, has been identified in amphibians by cDNA cloning. This mRNA, which we designate as TGF-beta 5, is developmentally regulated and highly expressed beginning at early neurula (stage 14) and in many adult tissues in Xenopus laevis. Following the first methionine, the putative precursor protein has a hydrophobic region, approximately 22 amino acids long, which probably represents a signal sequence, similar to that found in TGF-beta s 1-3. The precursor also has potential sites for glycosylation, integrin binding (RGD), and a tetrabasic amino acid (RKKR) site for potential cleavage of the precursor peptide to a biologically active protein. The putative mature protein consists of 112 amino acids with 9 cysteines and has 76, 66, 69, and 72% identity to TGF-beta s 1-4, respectively.

Amino Acid Sequence↗
PubMed1986

Quantitative analysis of stress thallium-201 myocardial scintigrams: a multicenter trial.

Previously we validated a method for quantification of 201TI myocardial stress distribution and washout in which the patient's stress and washout circumferential profiles are compared with observed normal limits. The present study reports the results of a multicenter trial in which this method, utilizing normal limits from our institution, was employed to evaluate the presence, location, and extent of coronary artery disease (CAD). The normal limits utilized were generated from 49 patients having a low likelihood of CAD. The study population included 157 patients from four centers in the United States and Canada as well as a comparative prospective population from Cedars-Sinai Medical Center (CSMC) of 51 patients with CAD, 30 patients with normal coronary arteriograms, and 30 additional low-likelihood normals. The results in the combined centers regarding overall detection of CAD revealed a sensitivity of 84% and a frequency of test normality in the patients with low likelihood of CAD of 88%, compared to a sensitivity of 82% and true normalcy rate of 83% obtained in the prospective CSMC population. The sensitivity for detecting disease increased according to the extent of angiographic CAD in both the multicenter sites and the prospective CSMC group. Regarding localization of disease, similar sensitivities and specificities for detecting disease in individual coronary arteries were found in the multicenter sites and the prospective CSMC population. The results indicate that our method for quantifying 201TI stress-redistribution scintigrams utilizing standard normal limits can be applied at other institutions using a variety of scintillation cameras with similar accuracy to that currently obtained at our institution.

Adult↗
PubMed1985

Left tension pneumothorax masquerading as anterior myocardial infarction.

Spontaneous pneumothorax is an emergency that can present with variable signs and symptoms. Diagnosis of pneumothorax can be difficult, particularly in patients who present with unusual clinical findings. The electrocardiographic changes that develop with left pneumothorax are not widely known and can mimic acute myocardial ischemia. Our patient was admitted to the Cardiovascular Intensive Care Unit because of characteristic changes on the electrocardiogram. An admission chest film revealed left tension pneumothorax.

Diagnosis, Differential↗
PubMed1983

Beat-to-beat left ventricular performance in atrial fibrillation: radionuclide assessment with the computerized nuclear probe.

There is wide beat-to-beat variability in cycle length and left ventricular performance in patients with atrial fibrillation. In this study, left ventricular ejection fraction and relative left ventricular volumes were evaluated on a beat-to-beat basis with the computerized nuclear probe, an instrument with sufficiently high sensitivity to allow continuous evaluation of the radionuclide time-activity curve. Of 18 patients with atrial fibrillation, 5 had mitral stenosis, 6 had mitral regurgitation, and 7 had coronary artery disease. Fifty consecutive beats were analyzed in each patient. The mean left ventricular ejection fraction ranged from 17 to 51%. There was substantial beat-to-beat variation in cycle length and left ventricular ejection fraction in all patients, including those with marked left ventricular dysfunction. In 14 patients who also underwent multiple gated cardiac blood pool imaging, there was an excellent correlation between mean ejection fraction derived from the nuclear probe and gated ejection fraction obtained by gamma camera imaging (r = 0.90). Based on beat-to-beat analysis, left ventricular function was dependent on relative end-diastolic volume and multiple preceding cycle lengths, but not preceding end-systolic volumes. This study demonstrates that a single value for left ventricular ejection fraction does not adequately characterize left ventricular function in patients with atrial fibrillation. Furthermore, both the mean beat-to-beat and the gated ejection fraction may underestimate left ventricular performance at rest in such patients.

Aged↗
PubMed1983

Gold-195m for serial first pass radionuclide angiocardiography during upright exercise in patients with coronary artery disease.

Sequential first pass radionuclide angiocardiography can be performed in rapid succession using gold-195m because of its low radiation dose and short half-life (30.5 seconds). In 25 patients with known or suspected coronary artery disease, first pass studies with gold-195m were obtained using a computerized multicrystal gamma camera at rest (n = 29), at the end of each 3 minute stage of exercise (n = 25) and immediately after exercise (n = 23). In 13 patients, assessment of left ventricular function during exercise with gold-195m was combined with thallium-201 stress scintigraphy. Left ventricular ejection fraction at rest assessed with technetium-99m and gold-195m correlated well (r = 0.93). In addition, repeat left ventricular ejection fractions at rest with gold-195m correlated closely (r = 0.96). Comparing peak exercise left ventricular ejection fraction with ejection fraction at rest, abnormal left ventricular reserve was found in 20 of 25 patients. Various abnormal patterns of left ventricular ejection fraction response were noted, showing the diagnostic potential of serial exercise angiocardiography. Thallium-201 myocardial images, obtained on a single crystal gamma camera after multiple gold-195m injections, were all of good diagnostic quality and were abnormal in 10 of 13 patients. Thus, multiple high count rate first pass studies can be obtained with gold-195m during and after exercise, allowing serial study of physiologic changes in left ventricular function during exercise. Thallium-201 myocardial imaging can be performed using the same exercise test, providing direct comparison of myocardial function and perfusion.

Adult↗