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Biomedical subjects

D C Sullivan

Publications and source records attributed to D C Sullivan.

At least 55 records · Page 3Linked to original sources
PubMed1991

Measurement of force applied during mammography.

The discomfort that patients experience during mammography is probably related to a variety of factors, one of which might be the amount of compression used. The authors measured the amount of force applied to the breasts during mammography and the resulting breast thickness in 560 women and correlated these measurements with the patient's subjective impression of the examination. The amount of force applied ranged from 49 to 186.2 N (median, 122.5 N). Breast thickness ranged from 10 to 88 mm (median, 46.5 mm). Forty-seven women (8%) rated the examination as painful (ie, mammography was either "very uncomfortable" or "intolerable"). Logistic regression analysis revealed a highly significant relationship between probability of a painful response and ratio of force to thickness (P = .007). Current guidelines suggest that maximum available force be at least 160 N but not more than 200 N. However, because increasing force is associated with increasing likelihood of pain, technologists should be aware that these recommended maximum limits are not intended to be used routinely for all women. In this study, high-quality mammograms were obtained in a majority of women with forces less than the maximum available level.

Breast↗
PubMed1991

In vivo measurements of ultrasonic beam distortion in the breast.

The phase aberrations encountered by ultrasonic pulses propagating through breast tissue in twenty-two female volunteers were measured. The experiments were designed to assess the impact of these aberrations on clinical ultrasonic image quality for a variety of transducer and imaging geometries. The phase aberration profiles of a given patient were correlated with the amount of parenchymal tissue determined from that patient's mammogram. These data are useful in assessing the image quality achievable with conventional ultrasonic imaging systems, and the potential application of adaptive ultrasonic imaging systems. The results indicate that phase aberrations significantly degrade breast image quality for typical transducer frequencies and sizes.

Breast Neoplasms↗
PubMed1990

Temporal regulation of equine herpesvirus type 3 transcription.

The transcription of equine herpesvirus type 3 (EHV-3; equine coital exanthema virus) has been examined and found to be temporally regulated into three classes: immediate early (IE), early (E), and late (L). Hybridization of in vivo 32PO4-labeled transcripts revealed that IE transcript(s) are derived exclusively from the inverted repeat segments (IRs) of the viral genome, while E and L transcripts are not restricted to any specific region of the genome. Northern blot analysis of EHV-3 IE RNA revealed a single transcript of approximately 5.7 kb (3.8 MDa). We have previously shown that transcription of equine herpesvirus type 1 (EHV-1) DNA is temporally regulated and produces a single 6 kb IE RNA which is derived from the IRs segments. In this paper, we show that the EHV-1 and EHV-3 IE RNA species are homologous, reflecting the colinearity of the genomes of these two related viruses. While four IE polypeptides are synthesized in EHV-1 infected cells in the presence of actinomycin D following the removal of a cycloheximide block, only one major IE polypeptide (180 kDa) is detectable in EHV-3 infected cells under these conditions. However, immunoprecipitation of EHV-3 infected cell extracts with polyvalent rabbit antisera to IE1 of EHV-1 revealed at least two other viral specific IE polypeptides.

Animals↗
PubMed1989

Synthesis and processing of equine herpesvirus type 1 glycoprotein 14.

Glycoprotein 14 (gp14) of equine herpesvirus type 1 (EHV-1), the homolog of herpes simplex virus (HSV) glycoprotein B (gB), was investigated employing a panel of monoclonal antibodies to ascertain the regulatory class, rate of synthesis, and type of glycosylation of this polypeptide. Application of immunoprecipitation, Western blot, and SDS-PAGE analysis in conjunction with the use of metabolic inhibitors (cycloheximide, antinomycin D, phosphonoacetic acid, tunicamycin, and monensin), and time-course and pulse-chase experiments revealed the following information: (1) Three gp14-related polypeptides with molecular weights of 138 kilodaltons (K), 77-75K, and 55-53K are present in EHV-1-infected cell extracts. (2) All three species are synthesized in the presence of the DNA synthesis inhibitor phosphonoacetic acid although their synthesis is enhanced by DNA replication, indicative of a beta-gamma class molecule. (3) The 138K species is synthesized first as a precursor of the smaller species of gp14, the 77-75K and 55-53K forms. (4) Use of glycosylation inhibitors and digestion of immunoprecipitated gp14 with endoglycosidases indicate that the primary translation product is a 118K molecule which is cotranslationally glycosylated to the 138K form by the addition of high mannose oligosaccharides. (5) The 77-75K species contains both high mannose and hybrid oligosaccharides while the 55-53K form of gp14 contains some complex oligosaccharides. (6) In the absence of a reducing agent, the 138K polypeptide and a large 145K species are observed in both infected cell extracts and purified virions. Thus, EHV-1 gp14 appears to be synthesized as a large precursor molecule of 138K and is proteolytically cleaved to two smaller forms, 77-75K and 55-53K, which are linked by a disulfide bond(s) to form a 145K complex. This model of gp14 synthesis and maturation is similar to those proposed for a number of HSV gB equivalents found in the Alphaherpesvirnae.

Animals↗
PubMed1989

Breast skin calcifications: localization with a stereotactic device.

Calcifications that lie within the skin of the breast may be mistakenly thought to be intraparenchymal on mammograms if they are projected over breast tissue in two views. A simple, reliable technique was developed to determine calcification location. It uses a commercially available stereotactic localization device and has been used successfully in six patients.

Breast Diseases↗
PubMed1988

Characterization of equine herpesvirus type 1 immediate early proteins.

EHV-1 immediate early (IE) gene expression in lytic infection results in the production of four high mol wt immediate early polypeptides (IEPs), designated IE1, IE2, IE2, and IE4; however, IE transcription is limited to the synthesis of a single 6-kb mRNA. Together, these findings raised questions as to whether the four IEPs were related products of the same gene. In the present study the IEPs were characterized with respect to their structural similarities, antigenic relatedness, and postsynthetic modifications. IE1 was the most abundant IEP, in that it accounted for approximately 80% of the IEP-incorporated radiolabel in infected rabbit kidney cells labeled under IE conditions with [35S]methionine or 14C-labeled amino acid mixtures. IE1 also was the major phosphorylated species. Limited proteolytic digestion of isolated radiolabeled IEP bands with Staph V8 protease yielded virtually identical fragment profiles in SDS-PAGE, as did digestions with chymotrypsin and N-chlorosuccinimide. Monospecific rabbit antisera raised against each of the four isolated IEPs reacted with all the IEP species in immunoblotting assays. Pulse-chase experiments indicated that all the IEPs were detectable immediately after a 15-min pulse and that several alterations in the IEP profile occurred during subsequent chase periods. Thus, the EHV-1 IEPs are closely related structurally and antigenically and appeared to be either produced simultaneously or processed to yield the individual forms immediately.

Antibodies, Viral↗
PubMed1988

Nonpalpable breast lesions at biopsy. A detailed analysis of radiographic features.

Several studies have demonstrated that mammographic screening of asymptomatic women results in a lower mortality rate where breast cancer is concerned. Often, screening mammograms reveal a nonpalpable radiographic abnormality and the diagnosis must be determined by an excisional biopsy after radiographic needle localization. The mammographic features associated with 179 nonpalpable breast abnormalities biopsied after radiographic needle localization were carefully characterized. There were 41 carcinomas (23%) in the series. The aim of this study was to determine which radiographic findings, if any, strongly portend the presence of either a malignant or benign lesion. Mammographic features that were commonly associated with malignancy include a change from a previous mammogram, a distortion of the surrounding architecture, the association of a soft tissue density and calcifications, and the presence of more than ten calcifications in the lesion. The radiographic abnormalities which were more commonly associated with benign disease include well-defined densities without calcifications, asymmetric densities without calcifications, and abnormalities consisting solely of a focus of mammographic calcifications that have fewer than ten concretions. The incidence of malignancy in lesions having these mammographic characteristics was only 5.5%. On the basis of these results alone, no firm threshold for biopsy can be recommended. The risks of deferring biopsy until there is worsening of the mammographic image remains to be determined.

Biopsy, Needle↗
PubMed1988

Effects of ECT on brain structure: a pilot prospective magnetic resonance imaging study.

The authors describe a pilot prospective investigation of the effects of ECT on brain structure using magnetic resonance imaging (MRI). In nine patients with major depression, a course of ECT produced no acute changes in brain structure according to blind raters' assessments of cortical atrophy and global comparison of pre- and post-ECT studies. There were also no significant changes in the ventricle-brain ratios. Pre-ECT brain abnormalities were common in these patients yet were also unaffected by ECT. Future MRI studies of ECT should include more subjects and should address long-term changes and subtle brain abnormalities.

Adult↗
PubMed1986

Oncogenic transformation of primary hamster embryo cells by equine herpesvirus type 3.

Infection of nonpermissive primary hamster embryo cells with equine herpesvirus type 3 (EHV-3; multiplicity of infection = 10 pfu/cell) resulted in an abortive infection and the development of several hundred foci of rapidly growing cells. Five of these foci were chosen at random for the establishment of transformed cell lines, designated EVD-1 (equine venereal disease) through 5. These transformed cell lines exhibited altered biological properties typical of transformed cells, including immortality, growth to high saturation density, colony formation in soft agar, reduced serum requirements, aneuploid karyotype, and oncogenicity in syngeneic animals. Subsequently, five corresponding tumor cell lines (EVD-1T through 5T) with similar biological properties were established. All EHV-3 transformed and tumor cell lines have been shown to express EHV-3-specific proteins by indirect immunofluorescence assays employing rabbit antisera to EHV-3 infected equine cells. None of the transformed cell lines were found to release infectious virus by infectious center or cocultivation assay or to contain viral particles by electron microscopy.

Animals↗
PubMed1986

Regional pulmonary distribution of iodine-125-labeled oleic acid. Its relationship to the pattern of oleic acid edema and pulmonary blood flow.

Oleic acid infusion in dogs produces a patchy, predominantly peripheral lesion on CT scans. This study correlates the pattern of oleic acid injury with the distribution of infused oleic acid and pulmonary blood flow. Radiolabeled oleic acid (I-125, 0.05 ml/kg) and radiolabeled 15-micron microspheres (Co-57) were infused into the right atria of 11 dogs. Oleic acid was given after the microspheres in six dogs and before microspheres in five dogs. Ten minutes after infusion, the lungs were removed. Four transverse slices (0.5 cm thick) of the lower lobes were taken from each dog and cubed. Samples were grouped into three regions of the transverse slice: outer, middle, and inner concentric rings. In both groups, I-125 (oleic acid) activity was greater in the outer than the middle and inner concentric layers (P less than 0.001). When Cobalt-57 microspheres were given before oleic acid, Cobalt-57 activity was marginally lower in the outer layer compared with the middle and inner layers. However, when oleic acid was given first, microsphere activity in the outer layer was significantly lower (P less than 0.001) than the middle layer. Thus, oleic acid was preferentially distributed to the peripheral regions of the lung, similar to the regions of injury on CT. This distribution did not correspond to the pattern of pulmonary blood flow as indicated by the microspheres. Immediately after oleic acid infusion, pulmonary blood flow to the periphery was reduced, reflecting a response to the predominantly peripheral injury by oleic acid.

Animals↗
PubMed1986

Distribution of 15- and 137-mu diameter microspheres in the dog lung in the axial plane.

Oleic acid infusion, as a model of fat embolism, produces a predominantly peripheral lesion in the dog lung. The lung injury corresponds to the peripheral distribution of labeled oleic acid. The basis for this distribution of oleic acid is not known. Our hypothesis for this nonuniform distribution is that particle diameter plays a role in the subsequent distribution of infused oleic acid and the resulting lung injury. We injected 15-mu microspheres 85Sr and then 137-mu microspheres (141Ce) into the right atria of seven dogs, which were killed and the lungs removed. Analysis of the distribution of the two different diameter microspheres within axial slices from the left caudal lobe of each dog revealed a peripheral distribution of the larger diameter microspheres not seen with the smaller microspheres.

Animals↗
PubMed1986

Genetic relatedness and colinearity of genomes of equine herpesvirus types 1 and 3.

The arrangement and location of homologous DNA sequences within the genomes of equine herpesvirus type 1 (EHV-1) and EHV-3 were investigated by using Southern blot hybridization analyses conducted under stringent conditions. Recombinant plasmid libraries comprising 95 and 84% of the EHV-1 and EHV-3 genomes, respectively, were labeled with 32P-deoxynucleotides by nick translation and were used as probes in filter hybridization studies. The DNA homology between the EHV-1 and EHV-3 genomes was dispersed throughout the genomes in a colinear arrangement. Significant hybridization was detected between the EHV-1 short region inverted repeat sequences, which are known to encode immediate early transcripts, and the corresponding EHV-3 inverted repeat sequences. Interestingly, probes derived from the EHV-1 heterogeneous region, which is adjacent to the EHV-1 short region, hybridized strongly to EHV-3 DNA sequences within a similar genomic location, but did not reveal any corresponding heterogeneity within the EHV-3 genome. Our results demonstrated that there is a highly conserved evolutionary relationship between EHV-1 and EHV-3 and provided the foundation for further investigations to determine whether similarities in protein function underpin the genetic relatedness between these two herpesviruses.

DNA, Viral↗
PubMed1985

Intraperitoneal chromic phosphate P 32 suspension therapy of malignant peritoneal cytology in endometrial carcinoma.

Malignant peritoneal cytology in patients with endometrial carcinoma is a poor prognostic feature, identifying patients at high risk for early intra-abdominal recurrence. Between 1977 and January, 1983, 65 women with endometrial carcinoma who had malignant peritoneal cytology were treated with adjuvant intraperitoneal radioactive chromic phosphate P 32 suspension. Fifty-three patients (80%) were clinical Stage I, nine (14%) were Stage II, and three (7%) were clinical Stage III. Life-table estimates of disease-free survival were 89% for clinical Stage I patients and 94% for surgical Stage I patients beyond 24 months. One patient developed an intraperitoneal recurrence, four had simultaneous intraperitoneal and extraperitoneal recurrences, and six developed recurrences outside of the peritoneal cavity. Few significant acute complications occurred after therapy with radioactive chromic phosphate P 32 suspension. Chronic intestinal morbidity that required surgical correction was encountered in five of 17 patients (29%) who received adjuvant pelvic radiation, compared to none of the 48 patients (0%) who received only radioactive chromic phosphate P 32 suspension (p less than 0.001). Intraperitoneal instillation of radioactive chromic phosphate P 32 suspension is effective therapy for patients with malignant peritoneal cytology from endometrial carcinoma. Caution should be exercised when radioactive chromic phosphate P 32 suspension and external radiation therapy are combined.

Adenocarcinoma↗