Biomedical subjects
K Ellis
Publications and source records attributed to K Ellis.
One piece of paper we can't do without.
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Systemic effects and safety of intravenous dipyridamole in elderly patients with suspected coronary artery disease.
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Tn2501, a component of the lactose transposon Tn951, is an example of a new category of class II transposable elements.
Tn2501 is a cryptic class II transposon found as part of the lactose transposon Tn951. Insertional inactivation and nucleotide sequence analysis of Tn2501 allowed us (i) to localize the transposase (tnpA) and the resolvase (tnpR) genes as well as the resolution site (res) of Tn2501 and (ii) to compare Tn2501 with other well-known elements of the two subgroups of class II transposons (Tn3, gamma delta, Tn951, IS101; and Tn21, Tn501, Tn1721). The genetic organization of Tn2501 is similar to that of Tn3 with divergent transcription of the tnpA and tnpR genes away from the intervening res site. The tnpR gene of Tn2501 shows weak homology with that of Tn3 and even less with those of Tn21 and Tn501. However, the tnpA gene and the inverted repeat sequences of Tn2501 present more homology with those of Tn21 and Tn501 than with those of Tn3. Complementation studies showed that TnpA- mutants of Tn2501 can be complemented, at a low frequency, by the Tn21 transposase. None of the tested transposons complemented TnpR- mutants of Tn2501.
The current state of residency and fellowship training programs in pulmonary and cardiac radiology.
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In vivo effect of ciprofloxacin on plasmid-mediated resistance.
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Hypoplastic left heart syndrome: report of a unique survivor.
A remarkable patient is described, a child who has survived until the age of 7 years with hypoplastic left heart syndrome (mitral and aortic atresia) without surgical intervention. The child has led an active, normal life and, aside from minimal cyanosis, has remained asymptomatic. The unique clinical course for this patient is the result of a number of favorable hemodynamic factors that have not been previously reported in an individual patient with hypoplastic left heart syndrome and intact ventricular septum widely patent ductus arteriosus, adequate retrograde coronary flow, unrestricted pulmonary venous return, and absence of significant vascular obstructive disease. This documentation of long-term survival in a child without surgical treatment for mitral and aortic atresia suggests that successful early palliative treatment for infants with this syndrome could also result in a favorable prognosis.
Role of chest radiography in predicting the extent of airway disease in patients with suspected pulmonary embolism.
An independent evaluation of the chest radiographs and ventilation-perfusion (VP) scintigrams of 119 patients (121 studies) was performed to assess the ability of radiographic findings to indicate the extent of ventilation abnormalities in patients suspected of having pulmonary embolism (PE). VP scans were obtained with krypton-81m in 72 cases and with xenon-133 in 49. All scintigrams showing ventilation abnormalities in greater than 50% of the lung were considered indeterminate for PE, owing to an increased likelihood of false-negative interpretations, as reported in previous studies. Indeterminate VP studies were found in all 21 patients who had radiographic findings of widespread obstructive pulmonary disease (OPD), in 35% with radiographic findings of focal OPD (P less than .001), and in only 18% with no OPD seen radiographically (P less than .001). VP scintigraphy is likely to be indeterminate for PE when widespread OPD is seen by chest radiography and ventilation imaging may not be warranted in these patients.
Endobronchial osseous foreign body: computed tomographic evaluation.
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Stroke: what to say about sex.
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Risk factors for postmenopausal osteoporosis.
Fifty-eight women with postmenopausal osteoporosis (crush fracture of the spine) were compared with 58 age-matched normal women. The osteoporotic women had lower total-body calcium levels and bone mineral content of the radius, had undergone an earlier menopause, smoked cigarettes more, and had breast-fed less often. They also had lower levels of estrone, estradiol, and testosterone and reduced levels of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D. These findings suggest the presence of changeable risk factors for the development of osteoporosis. Smoking should be discouraged. An adequate intake of calcium and vitamin D should be ensured. It is the opinion of the authors that those women who have had an early menopause or who have a low bone mass at the time of menopause should be given the choice of medically supervised replacement therapy with estrogen and progesterone.
A model for involutional bone loss.
Bone mass of the total skeleton and distal radius were measured by in vivo neutron activation analysis and single photon absorptiometry, respectively, in 403 healthy white women and 151 healthy white men. In addition, the density of L-2 to L-4 (bone mineral content of the spine [BMCs]) was measured by dual photon absorptiometry in 159 of these women and in 56 women with the vertebral crush fracture syndrome. The rate of loss of total body calcium (TBCa) and bone mineral content of the radius (BMCr) was linear in men and was slower than in women. The best fit for TBCa and the bone mineral content of the distal radius and spine as a function of age in women was with a two-phase regression. The TBCa and BMCr could be used as well as BMCs to identify women with crush fractures. The ratios of BMCs/TBCa, BMCs/BMCr, and TBCa/BMCr did not differ among women with crush fractures and age-matched normal individuals. Our data do not support the hypothesis that women with vertebral crush fractures have preferential loss of spinal bone.
Involvement of kil and kor genes in the phenotype of a host-range mutant of RP4.
Plasmid pRP761 is a derivative of the promiscuous plasmid RP4, which has a Tn76 insert 1.8 kb from its EcoRI site within the trfB region (Barth 1979). This mutation was pleiotropic, having three effects: the plasmid is unstably maintained in E. coli, it reduces the growth rate of its host and it has suffered a reduction in host-range. We show that pRP761 has reduced expression from both its korA and korB genes and that Tn76 has inserted between them. Fragment exchange experiments showed that this is the only mutant region in pRP761 and is therefore solely responsible for the pleiotropic effects. A spontaneous deletion derivative pRP761-6 has lost Tn76 and its adjacent kilA and korA genes: it has reacquired stability, does not inhibit host growth but is still reduced in its host-range. The provision of cloned korA+ in trans complements the first two phenotypic effects in pRP761 to a large extent, but neither korA+ alone nor korA+ with korB+ complements the host-range reduction in pRP761 or pRP761-6. A possible explanation for these results is that there is a site between korA and korB, affected by the Tn76 insert, that is essential to stable replication of these plasmids in some of their bacterial hosts.
Total body phosphorus in postmenopausal women.
Total body phosphorus (TBP) and total body calcium (TBCa) were measured by neutron activation analysis and whole body counting in 82 white women who were 1-6 years postmenopausal. Mean TBP was 395 g +/- 6.3 (SE). There was no evidence for subgroups of patients with either higher or lower TBP. The TBP was significantly related to TBCa, as well as to the bone mineral content of the distal radius. Positive associations were found between TBP and urinary phosphate excretion as well as serum 1,25(OH)2D levels (r = 0.30; p = 0.017; n = 48). Serum phosphate was related to 1,25(OH)2D levels and the number of years since menopause.
Sodium excess in postmenopausal osteoporosis.
The sodium excess (Naes) which represents the nonexchangeable sodium compartment of bone was calculated from the total body sodium and total body chlorine of 95 women with vertebral crush fracture syndrome. No evidence was found for a subpopulation with increased or decreased Naes or Naes:TBCa ratio (TBCa is total body calcium which reflects total skeletal mass). Correlations in the osteoporotic women were found between the Naes and serum alkaline phosphatase (r = 0.31), PTH (r = 0.53), urinary hydroxyproline excretion (r = 0.42) and serum 250H vitamin D (r = -0.32). These data suggest that the state of vitamin D nutrition as well as parathyroid hormone levels may influence the quantity of sodium in bone in osteoporotic women. It is of great interest that these relationships were not observed in two control populations consisting of elderly women and women who recently underwent spontaneous menopause.
Spontaneous complete closure of a congenital coronary artery fistula.
The first documentation is reported of spontaneous closure of a coronary artery to right ventricle fistula that was demonstrated initially in a 14 month old boy. Over a 4 year period after diagnosis, the characteristic continuous murmur gradually disappeared. When the patient was 5 1/2 years of age, selective coronary arteriography showed normal coronary vessels and circulation. Six other cases of coronary fistula observed during the past 10 years are also reviewed. This study supports the rationale for clinical follow-up rather than obligatory surgical intervention in asymptomatic patients with a small shunt who have no evidence of myocardial dysfunction.
Computed tomography of intrathoracic goiters.
Ten patients with intrathoracic goiters were evaluated by computed tomography (CT). In comparison with chest radiographs, CT showed additional features helpful in suggesting the correct diagnosis. These observations included: (1) clear continuity with the cervical thyroid gland (8/10 cases); (2) well defined borders (9/10); (3) punctate, coarse, or ringlike calcifications (8/10); (4) nonhomogeneity (9/10) often with discrete, nonenhancing, low-density areas (6/10); (5) precontrast attenuation values at least 15 H greater than adjacent muscles (4/10) with more than 25 H after contrast enhancement (8/8); and (6) characteristic patterns of goiter extension into mediastinum.