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Biomedical subjects

K Ellis

Publications and source records attributed to K Ellis.

At least 91 records · Page 5Linked to original sources
PubMed1977

Persistence of the fetal circulation: radiologic considerations.

Persistence of the fetal circulation is a recently recognized cause of severe cyanosis in newborn full term infants. Abnormally elevated pulmonary vascular resistance apparently stimulated by hypoxia, acidosis, and/or hyperviscosity results in cyanosis due to large right-to-left shunts through persistent fetal channels (patent foramen ovale and patent ductus arteriosus). Initial chest radiographs demonstrate clear lungs, decreased, normal, or mildly prominent pulmonary vascularity, and normal to moderately enlarged cardiac silhouettes. Angiocardiography, when required to rule out cyanotic congenital heart disease, demonstrates normal intracardiac anatomy, normal great vessel relationships, and right-to-left shunting across the patent foramen ovale and patent ductus arteriosus. Significant tricuspid regurgitation occurs in some of these infants, associated with variable right ventricular dilatation; the left ventricle is normal. The majority of babies with this condition ultimately survive. Treatment consists of intensive care including oxygen therapy and correction of acidosis. Vasodilators such as tolazoline may be helpful.

Coronary Angiography↗
PubMed1977

Radiographic morphometry and osteopenia in spinal osteoporosis.

Measurements of bone mineral content and total-body calcium, normalized and expressed as ratios, were compared with radiographic morphometry in 45 women who had spinal osteoporosis. The radiographic indices examined included the femoral score, the femoral trabecular pattern, the biconcavity and metacarpal indices, and the total peripheral score. Both ratios and all the radiographic indices except the femoral trabecular pattern were found to be related to the number of dorsal spine fractures. The relationships observed support the following conclusions: (A) the femoral score and the metacarpal index are related to the degree of osteopenia; (B) the biconcavity index reflects the extraskeletal factors that are pathogenic in spinal osteoporosis; (C) a reduced femoral trabecular pattern index is associated with spinal osteoporosis, although this measurement is not related to the degree of osteopenia; and (D) it may be imprudent to diagnose osteoporosis from the presence of lumbar compression fractures.

Age Factors↗
PubMed1976

Myocardial blood flow in congestive and hypertrophic cardiomyopathy: relationship to peak wall stress and mean velocity of circumferential fiber shortening.

Myocardial blood flow/unit mass (MBF) and the determinants of myocardial oxygen consumption were measured in seven control subjects (group I) and 15 patients (pts) with cardiomyopathy (CM), group II (group IIa-congestive CM: 10 pts; group IIb-hypertrophic CM: 5 pts). In group I left ventricular (LV) MBF was 64 +/- 8 (SD) ml/100g-min; it was significantly lower in IIa (45 +/- 15 ml/100g-min, P less than 0.01) and IIb (39 +/- 7 ml/100g-min, P less than 0.01). However, calculated total LV flow (LV mass X MBF) was increased in the two CM groups. In nine CM pts, LV MBF increased in response to atrial pacing from 41 +/- 7 to 63 +/- 13 ml/100g-min. In group IIa, calculated peak wall stress was normal (4.39 +/hortening (MVcf) was significantly reduced (0.53 +/- 0;18 vs 1.26 +/- 0.12 circum/sec, P less than 0.01). In IIb, MVcf was normal but peak stress was significantly reduced (2.80 +/- 0.75 vs 4.51 +/- 1.10 dynes/cm2 X 10(5), P less than 0.05). Multiple regression analysis based on all pts yielded, MBF - 16.9 MVcf + 9.30 Stress + 0.26 Heart Rate - 26.4 (r=0.79). The data indicate that MBF is reduced in CM patients and the regression analysis suggests that MBF in these 22 pts with normal coronary arteriograms was determined largely by heart rate, peak stress, and ventricular performance.

Blood Flow Velocity↗
PubMed1976

Subpulmonary obstruction in congenitally corrected transposition of the great arteries due to ventricular membranous septal aneurysms.

The clinical, hemodynamic, and angiographic observations, as well as the surgical approach used for repair in three patients with congenitally corrected transposition of the great arteries and ventricular membranous septal aneurysms, are presented. In two of the three patients the membranous septal aneurysm caused subpulmonary obstruction, with 94 and 125 mm Hg systolic gradients. In each patient the aneurysm was demonstrated by angiocardiography, which also showed differences in size and shape with cardiac systole and diastole. Review of the previously described reports indicates that patients with congenitally corrected transposition often display various forms of pulmonary outflow obstruction and when a ventricular membranous septal aneurysm exists, a significant subpulmonary obstruction is present in most patients. The unique anatomic relationship between the pulmonary artery and a ventricular membranous septal aneurysm in patients with transposition of the great arteries with and without atrioventricular discordance explains why subpulmonary obstruction sometimes develops.

Adolescent↗
PubMed1976

Effects of growth hormone in osteoporosis.

The effect of chronic administration of growth hormone (GH) to osteoporotic patients was studied using the techniques of total body neutron activation analysis, whole body counting, calcium tracer kinetics, photon absorptiometry, quantitative microradiography, and urinary hydroxyproline. Two dosage schedules were utilized for six months each: 2 units daily and 0.2 w3/4 units of GH daily (where W represents body weight expressed in kg). The lower dosage (2 units) did not produce any appreciable change in the indices studied. Following the higher dose, no evidence of any anabolic effect was apparent in most patients (i.e., no increase in total body levels of Ca, Na, K, P, or Cl). Increases were noted in the urinary calcium excretion rate and in the urinary hydroxyproline excretion. Bone mineral content decreased. The bone biopsies displayed an increase in bone formation and resorption surfaces in response to treatment, but these changes were not statistically significant. It may be concluded that under the conditions of this study, GH administration did not result in an increment in skeletal mass. Several side effects that are characteristic of acromegaly were observed, including hyperglycemia, hypertension, arthralgia, and the carpal tunnel syndrome. Because of the lack of demonstrated benefit and the associated complications of therapy, GH administration does not appear to be of value in the treatment of osteoporosis.

Bone and Bones↗
PubMed1976

Body composition and skeletal metabolism following pituitary irradiation in acromegaly.

The change in body composition in acromegaly that resulted from pituitary irradiation was examined using the technic of total body neutron activation analysis. Before treatment, increased ratios of total body P:Ca, P:K and Na:K were noted. After pituitary irradiation, the total body levels of P, Na and K were reduced in a proportion that indicated restoration of body composition towards normal. Skeletal mass (total body calcium) decreased into the range observed in osteoporosis in several patients. Trabecular bone mass, as reflected by the Singh Index, was consistently reduced, and two patients had vertebral compression fractures. Local bone mass as determined by photon absorptiometry was reduced when the values were normalized for age, sex and body size. It is postulated that in untreated acromegaly there is differential bone remodelling with an increase in cortical bone accompanied by a reduced trabecular bone mass. When reduction of hGH levels is accomplished with treatment, cortical apposition may decrease. Since the increased cortical bone mass probably aids in preventing vertebral compression fractures, the treated acromegalic patient may incur an increased risk of fractures. This risk may be increased further by the hypogonadism which may arise secondary to pituitary irradiation or surgery. It would be prudent to ensure that the hypogonadal acromegalic patient receives an adequate calcium intake and sex hormone replacement therapy.

Acromegaly↗
PubMed1975

The fat embolism syndrome.

The "shock lung syndrome," whenever associated with trauma, is probably in part the consequence of fat emboli, though aspiration, disseminated intravascular coagulation, microatelectasis, pulmonary edema, and hemorrhage due to other lung insults may be important in the etiology of many cases. When lung injury is due to fat emboli, there is an interval between the time of trauma and the onset of clinical symptoms and chest radiographic findings. The radiographic picture is that of a diffuse alveolar and interstitial lung density. In severe cases marked respiratory embarrassment requires the use of both oxygen therapy and mechanical respirators for survival.

Accidents↗
PubMed1975

Volume ejected in early systole. A sensitive index of left ventricular performance in coronary artery disease.

Indices based on early systolic ejection rates are theoretically more sensitive to ventricular performance than indices based on the entire systolic ejection (SE) period (mean ejection phase indices-MEPI): mean systolic ejection rate (MSER), mean normalized systolic ejection rate (MNSER) and mean velocity of circumferential fiber shortening (MVcf). The volume ejected in early systole is an indicator of the early rate of ejection. Accordingly, ventricular volume changes were determined by ventriculographic analysis for each thrid of SE in ml/sec (SER), as normalized systolic ejection rate (NSER), and as percent of stroke volume (PSV). In ten normal controls all these indices were higher in the first third compared to the other thirds of SE. Seven patients with diffuse ventricular disease had depressed values in the first third of SE. Despite "normal ventriculograms and normal MEPI, eight patients with left anterior descending coronary artery stenoses (greater than 60%) also had definitely depressed ejection indices during first third of systole. Detailed wall motion analysis in this group showed anteroapical hypokinesis isolated to the first third of SE. These data show that indices based on early SER are more sensitive than MEPI (MVcf, MNSER) for detecting abnormalities in ventricular performance in coronary artery disease;

Adult↗
PubMed1975

The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

Measurements of mean left ventricular (LV) and regional myocardial blood flow rates were made at rest in 161 patients with 133Xe and a multiplecrystal scintillation camera. Myocardial perfusion rates were correlated with assessments of the degree of coronary artery disease made from the arteriograms obtained during the same studies. In patients with normal coronary arteries without heart failure, the presence of hypertension, aortic stenosis, or aortic insufficiency was not associated with changes in mean LV perfusion from the control value of 61+/-7 ml/100 g-min. However, mean LV perfusion was significantly reduced in patients with normal coronary arteries who had cariomyopathy and impaired ventricular performance. Mean LV perfusion was not significantly different from control values in patients with "mild" coronary artery disease (less than 50% obstruction) or in patients with significant isolated disease (greater than 50% obstruction) of the left anterior descending (lad) artery. Significant reductions in mean LV perfusion were found in patients with greater than 50% obstruction of two coronary arteries (LAD + right or LAD + circumflex) and in patients with triple-vessel disease. The average perfusion rate for regions distal to LAD obstructions in patients with isolated LAD disease was not lower than the LAD perfusion in control patients, but was significantly reduced in patients with LAD + right coronary artery disease (43+/-14 ml/100 g-min). In the latter group average perfusion distal to the LAD lesion was significantly lower than the average regional perfusion rate for the remainder of the LV. However, the mean blood flow rate for the remainder of the LV was also significantly lower than control values despite the lack of significant circumflex disease. The data demonstrate that the presence of radiographically "mild" or significant isolated LAD coronary disease is not associated with reductions in mean LV perfusion at rest, but that mean LV perfusion is reduced in the presence of significant disease of two or three coronary artieries. None of the patients experienced angina during the resting studies and most had clinical evidence of ventricular failure. The observation of depressed LV perfusion in this group, as in the patients with cardiomyopathy, raises the possibility that a lowered resting blood supply may be adequate for a reduced level of performance of a diseased ventricle. The lack of selective reductions of regional perfusion at rest in the majority of the patients with LAD lesions suggests that regional myocardial blood flow must be measured during an intervention which increases myocardial oxygen consumption in order to assess the physiological significance of lesions which are observed at coronary arteriography.

Adult↗
PubMed1975

Phonton absorptiometry and skeletal mass in the treatment of osteoporosis.

Thirty-six osteoporotic patients who underwent several therapeutic regimes were studied on two occasions by photon absorptiometry and total-body neutron activation analysis (TBNAA). These determinations were made at a mean interval of 8.9 plus or minus 0.8 months. The 8-cm radial site was chosen for the photon absorptiometry which was performed with the Norland-Instruments Densitometer. Mean initial bone mineral content (BMC) was 0.724 plus or minus 0.069 gm/cm and mean bone width was 1.235 plus or minus 0.072 cm. The mean percent change in BMC (%deltaBMC) was 1.02 plus or minus 4.2. The initial total-body calcium (TBCa) as determined by TBNAA was reduced when compared with values that would be expected from empirically derived formulas. The mean percent change in TB-Ca (%deltaTB-Ca) was -3.2 plus or minus 4.7. Most patients displayed a change in BMC and TB-Ca that was at least 2 s.d. greater than the precision of the methods used (%deltaTB-Ca greater than 2). No relationship was found between the deltaBMC and the deltaTB-Ca (r = 0.17). These findings suggest that changes in the radical BMC at the 8-cm site cannot be extrapolated to indicate changes in skeletal mass in response to treatment of osteoporosis. Whether photon absorptiometry at other sites or at multiple sites provides a closer relationship to changes in skeletal mass (TB-Ba) remains to be determined.

Activation Analysis↗
PubMed1975

Studies of regional myocardial perfusion in patients with coronary atherosclerosis, using xenon-133 and a multiple crystal scintillation camera.

Regional myocardial perfusion was measured in 164 patients at coronary arteriography. Washout of xenon-133 from multiple areas of the heart was monitored with a multiple crystal scintoooillation camera after tracer injection int the left or right coronary artery. Rate constants of radioisotope clearance were computed by monoexponential analysis of the initial portion of each washout curve. Regional myocardial blood flow rates in ml/100 g.min were calculated by the Kety formula. The pattern of local myocardial perfusion rates was compared to the coronary arteriogram obtained during the same study. In patients with normal coronary arteriograms, the average mean myocardial perfusion rate in the left ventricle (LV) significantly exceeded that of the right ventricle and the right atrial area. Mild heterogeneity of local myocardial flow rates in the LV was observed. In patients with essential hypertension, aortic stenosis, and aortic insufficiency, the average LV perfusion rates were similar to those of subjects with normal coronary arteriograms, pressures, and ventriculograms. The mean LV perfusion rates were significantly reduced in patients without coronary disease who had cardiomyopathy and cardiac failure.

Collateral Circulation↗