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Biomedical subjects

R G Lester

Publications and source records attributed to R G Lester.

At least 19 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↗
PubMed1984

President's address. The contributions of radiology to the diagnosis, management, and cure of breast cancer.

The role of radiology in the diagnosis and treatment of breast cancer is reviewed and placed in the context of advances in diagnostic radiology and radiation oncology in the overall care of patients with this disease. The author discusses the early history of mammography, the results of large-scale screening studies, improvements in the understanding of the biology of tumors, and the principles underlying the movement away from radical or modified radical mastectomy for tumor control.

Adult↗
PubMed1984

Low (type III) odontoid fracture: a new radiographic sign.

Dens fractures are frequently difficult to identify radiographically, particularly when it is only possible to obtain a lateral radiograph of the upper cervical spine. Further, when a dens fracture is identified in lateral projection, it is often difficult to distinguish the "high" (Type II) from the "low" (Type III) fracture. The authors describe an elongated "ring" density superimposed upon the body of the axis in the lateral cervical radiograph which, when horizontally disrupted, indicates a dens fracture and is a specific radiographic sign of the "low" variety.

Axis, Cervical Vertebra↗
PubMed1981

Computed tomography of chest trauma.

Computed tomography (CT) and radiography were used to study 20 patients with chest injuries. Excluding rib fractures, CT revealed 50 traumatic lesions ranging from extrapleural hematomas to pericardial fluid collections. In contrast, only 12 lesions were detected on the corresponding radiographs. While many of the processes demonstrated on CT were not life-threatening, substantial abnormalities such as pericardial effusion and diaphragmatic rupture were detected.

Diaphragm↗
PubMed1981

Computed tomography in blunt trauma.

Until now, CT has been utilized very little in the evaluation of the bluntly traumatized patient. Based on our early experience, we have attempted to demonstrate the CT features of a spectrum of injuries. Much of this information is new and additional studies will have to be performed to elucidate fully the benefits of computed tomography in the diagnosis of trauma. A method of study has been outlined which stresses the use of intravascular, oral, and, when needed, rectal contrast materials for study in these patients.

Abdominal Injuries↗
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↗