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Biomedical subjects

R G Lester

Publications and source records attributed to R G Lester.

13 recordsLinked to original sources
PubMed1990

Are implantation and pregnancy outcome impaired in diethylstilbestrol-exposed women after in vitro fertilization and embryo transfer?

Forty-six infertile women with a history of diethylstilbestrol (DES) exposure in utero underwent 149 stimulation attempts for in vitro fertilization (IVF). The mean (+/- SE) number of preovulatory oocytes harvested at retrieval and transferred was 3.9 +/- 3.3 (536/138) and 2.6 +/- 1.4 (328/124). When compared with patients with tubal factor infertility and less than or equal to 4 pre-embryos transferred, the clinical pregnancy rate (15.3% versus 22%) was not statistically different. However, the term/ongoing pregnancy rate was significantly lower in the study group (8% versus 16%). Comparison of the IVF outcome with different uterine anomalies as detected by hysterosalpingogram (n = 29) showed a trend for a worse prognosis in women with constrictions and a combination of T-shape and constrictions. It is concluded that implantation and pregnancy outcome are impaired in DES-exposed women after IVF.

Adult↗
PubMed1985

Pseudolesion of the chest. A conglomerate shadow on the lateral radiograph.

A pseudolesion encountered in the lateral chest roentgenogram of normal patients is described. This concatenation of shadows can produce an opacity which projects over the distal aortic arch and can simulate a mass or pneumonia. This pseudolesion can be found in 4 to 5 percent of normal lateral chest films and is formed by superimposition of normal upper lobe vascular structures.

Diagnosis, Differential↗
PubMed1979

Digital radiography using a computed tomographic instrument.

A prototype computed radiography (CR) system was evaluated for its efficacy as an independent diagnostic modality. Preliminary measurements of high contrast resolution, low contrast perceptibility, and dose were obtained. Clinical examinations including skull, abdomen, liver, gallbladder, biliary system, spine, and extremities were performed as an adjunct to either computed tomography or CR. The data suggest that CR can be an effective diagnostic imaging modality by itself. Advantages over conventional radiography include high scatter rejection, low patient dose, wide dynamic range, and good low contrast sensitivity for large objects; disadvantages, its long exposure time and relatively poor high contrast spatial resolution.

Biliary Tract↗
PubMed1978

Tetralogy of Fallot associated with uncommon lesions.

A patient presented with a a unique combination of cardiovascular abnormalities: tetralogy of Fallot, absent pulmonary valve, stenosis of peripheral pulmonary arteries, and partial anomalous pulmonary venous connection to the azygos vein. The salient aspects and associated lesion of each of these abnormalities are described.

Abnormalities, Multiple↗
PubMed1977

Risk versus benefit in mammography.

Controversy surrounds the use of mammography in asymptomatic women 35-49 years of age. There is agreement that routine mammography is useful beyond 50 years. By extrapolating data from relatively high radiation exposures, a radiation carcinogenic risk at diagnostic levels has been calculated by some workers. Benefit for asymptomatic women in the 35-49 year age group has been questioned. This paper presents evidence that significant numbers of breast cancers are found in this age period on the basis of x-ray examination alone. Data also indicate absorbed dose from modern-day mammography is half to one quarter of that previously assumed. Based on these data, mammography is recommended as a tool for diagnosis of nonpalpable carcinomas of the breast.

Adult↗
PubMed1976

Total anomalous pulmonary venous connection to the left vertical vein. A plain-film sign useful in early diagnosis.

Total anomalous pulmonary venous connection to the left vertical vein often may be recognized on the plain postero-anterior chest radiograph by the characteristic supracardiac shadow. This "snowman sign" is useful in older patients but rarely is apparent in infancy. In such young patients the authors have discovered a density anterior to the trachea on the lateral chest radiograph. This finding is present prior to the appearance of the snowman sign and should prove useful in the early diagnosis of this anomaly, facilitating prompt, appropriate treatment. Five representative cases are tabulated and developmental and clinical aspects are reviewed.

Child↗
PubMed1976

One-view mammographic screening?

Repeated mammographic exposures of asymptomatic women in the screening situation has raised questions regarding possible risks. Obtaining only one view, regardless of imaging technique, would approximately halve the exposure. While retrospective analysis indicates further investigation is warranted, one-view mammographic screening is not yet recommended. The lateral view, including the chest wall, would reduce exposure by approximatley 44% but little savings in technologist time could be anticipated.

Breast Neoplasms↗
PubMed1975

Substrate utilization and oxygen consumption by canine jejunal mucosa in vitro.

Oxygen consumption, carbon dioxide production, and substrate utilization by small pieces of canine jejunal mucosa have been measured in vitro. In the absence of added substrate, the Qo2 was 0.21 mumol/h per mg dry wt and the respiratory quotient (RQ) was 0.73 indicating the endogenous substrate to be lipid in nature. When glucose or galactose was added, Qo2 and RQ increased. Metabolism of the endogenous substrate was depressed by fructose but not by glucose or galactose. Less than 15% of the metabolized glucose and fructose was degraded to Co2; 80% of the metabolized glucose was recovered as lactate. Galactose disappeared at one-seventh the rate of glucose, but 40% of that metabolized was degrated to CO2. In all experiments Qo2 showed marked cyclic fluctuations with an amplitude of 30-40% of the mean value and a period of 30-40 min. For tissues from a single animal, the cycles were in phase on a clock time basis, indicating that the cycles were synchronized by some in vivo mechanism.

Animals↗
PubMedDate not supplied

X-ray appearance and clinical significance of left atrial wall calcification.

Ten patients with calcifications of the left atrium are reported with review of the literature. Calcification of the left atrium is frequently associated with history of rheumatic fever, longstanding congestive heart failure, atrial fibrillation, mural thrombus and embolization. Early recognition of such lesions is essential for the management of the patients, particularly when surgical intervention is contemplated. A practical classification of left atrial calcification is proposed according to the dominant lesion in each group: (a) Calcification of the left atrial appendage alone (Mitral stenosis). (b) cacification of all 3 component lesions of the left atrium, i.e., the left atrial appendage, the free wall, and the mitral valve (Severe mitral stenosis). (c) Calcification of the left atrium in MacCallum's patch alone (Mitral insufficiency).

Adult↗