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Biomedical subjects

S Erickson

Publications and source records attributed to S Erickson.

At least 19 recordsLinked to original sources
PubMed1992

Effects of dimethyl prostaglandin A1 on herpes simplex virus and human immunodeficiency virus replication.

We have investigated the direct effect of dimethyl prostaglandin A1 (dmPGA1) on the replication of herpes simplex virus (HSV) and human immunodeficiency virus type 1 (HIV-1). dmPGA1 significantly inhibited viral replication in both HSV and HIV infection systems at concentrations of dmPGA1 that did not adversely alter cellular DNA synthesis. The 50% inhibitory concentration (ID50) for several HSV type 1 (HSV-1) strains ranged from 3.8 to 5.6 micrograms/ml for Vero cells and from 4.6 to 7.3 micrograms/ml for human foreskin fibroblasts. The ID50s for two HSV-2 strains varied from 3.8 to 4.5 micrograms/ml for Vero cells; the ID50 was 5.7 micrograms/ml for human foreskin fibroblasts. We found that closely related prostaglandins did not have the same effect on the replication of HSV; dmPGE2 and dmPGA2 caused up to a 60% increase in HSV replication compared with that in untreated virus-infected cells. HIV-1 replication in acutely infected T cells (VB line) and chronically infected macrophages was assessed by quantitative decreases in p24 concentration. The effective ID50s were 2.5 micrograms/ml for VB cells acutely infected with HIV-1 and 5.2 micrograms/m for chronically infected macrophages. dmPGA1 has an unusual broad-spectrum antiviral activity against both HSV and HIV-1 in vitro and offers a new class of potential therapeutic agents for in vivo use.

Animals↗
PubMed1992

Color Doppler sonography in the evaluation of the adult acute scrotum.

Color Doppler sonography (CDS) was used to evaluate 35 adult males with acute scrotal discomfort. Correlative nuclear scintigraphy was performed in 15 patients. Surgical correlation was available in 10 patients with clinical follow-up in the remaining 25. The complete absence of intratesticular color flow was used as our criterion for testicular ischemia. This was found to be 100% sensitive and 100% specific in 8 patients with surgically confirmed testicular ischemia. Spontaneous detorsion was noted in one patient with hyperemia demonstrated by color imaging. Increased color flow was found in 20 patients with the clinical impression of scrotal inflammation. Nuclear scintigraphy and color Doppler imaging had 100% agreement in 15 patients. Color Doppler sonography is a useful and highly accurate diagnostic method in the evaluation of patients with the acute scrotal syndrome. Color flow imaging is comparable to nuclear scintigraphy in the diagnosis of testicular ischemia.

Acute Disease↗
PubMed1991

Hepatic metastases: CT versus MR imaging at 1.5T.

A prospective multi-institutional study was performed to compare the sensitivity of computed tomography (CT) and high-field magnetic resonance (MR) imaging (1.5T) in the detection of hepatic metastases. T1-weighted and 72-weighted spin-echo (SE) MR images were compared with noncontrast, dynamic, and delayed CT. Sixty-nine oncology patients were studied. Noncontrast CT showed an overall sensitivity of 57%, dynamic CT 71%, delayed CT 72%, T1-weighted SE MR 47%, and T2-weighted SE MR 78%. Although there was no statistically significant (p less than 0.05) difference among dynamic CT, delayed CT, and T2-weighted SE MR, these three methods were significantly more sensitive (p less than 0.005) than noncontrast CT or T1-weighted SE MR. T2-weighted SE MR was significantly more sensitive (p less than 0.006) than CT or T1-weighted SE MR in the detection of small (less than 1 cm) lesions. CT was more sensitive in the detection of extrahepatic disease. These data confirm the superiority of T2-weighted SE over T1-weighted SE pulse sequences at 1.5T.

Adult↗
PubMed1991

Regulation of the phage phi 29 prohead shape and size by the portal vertex.

Bacteriophage phi 29 of Bacillus subtilis packages its double-stranded DNA into a preformed prohead during morphogenesis. The prohead is composed of the scaffold protein gp7, the capsid protein pg8, the portal protein gp10, and the dispensable head fiber protein gp8.5. Our objective was to elucidate the phi 29 prohead assembly pathway and to define the factors that determine prohead shape and size. The structural genes of the phi 29 prohead were cloned and expressed in Escherichia coli individually or in combination to study form determination. The scaffold protein was purified from E. coli as a soluble monomer. In vivo and in vitro studies showed that the scaffolding protein interacted with both the portal vertex and capsid proteins. When the scaffold protein interacted only with the capsid protein in vivo, particles were formed with variable size and shape. However, in the presence of the portal vertex protein, particles with uniform size and shape were produced in vivo. SDS-PAGE analysis showed that the latter particles contained the proteins of the scaffold, capsid, head fiber, and portal vertex. These results suggest that the scaffolding protein serves as the linkage between the portal vertex and the capsid proteins, and that the portal vertex plays a crucial role in regulating the size and shape of the prohead.

Bacillus subtilis↗
PubMed1991

sRNA of phage phi 29 of Bacillus subtilis mediates DNA packaging of phi 29 proheads assembled in Escherichia coli.

The structural genes of the prohead of phage phi 29 of Bacillus subtilis and a small phi 29 RNA (sRNA) were cloned and expressed in Escherichia coli individually or in combination to study the role of the sRNA in prohead assembly and the mechanism of prohead morphogenesis. The genes coding for the proteins of the scaffold (gp7), the capsid (gp8), the portal vertex (gp10), and the dispensable head fiber (gp8.5) were expressed in E. coli and the gene products were assembled, with and without the presence of the sRNA, into uniform and prolate particles that resembled the typical native phi 29 prohead. No differences in particle size and shape were found between the particles of 7-8-8.5-10 (scaffold-capsid-fiber-portal vertex) and 7-8-8.5-10-RNA (scaffold-capsid-fiber-portal vertex-RNA), suggesting that the phi 29 sRNA was not required for phi 29 prohead assembly. The 7-8-8.5-10 particles produced in E. coli in the absence of phi 29 sRNA were fully competent to package phi 29 DNA in the defined in vitro DNA packaging system by the addition of purified sRNA. Moreover, these DNA-filled heads were assembled into infectious virions in extracts. Without the addition of the sRNA, the 7-8-8.5-10 particles were incompetent while the 7-8-8.5-10-RNA particles were competent in DNA packaging. Bacterial sRNA present in E. coli cannot substitute for the phi 29 sRNA. The assembly of prohead particles in E. coli indicated that host factors unique to B. subtilis were not required. The evidence that the phi 29 sRNA was not required for phi 29 prohead assembly and was not a fixed structural component of the phi 29 prohead favors the conclusion that the phi 29 sRNA is a specific enzyme or morphogenetic factor in DNA packaging.

Bacillus subtilis↗
PubMed1989

Computed tomographic features of esthesioneuroblastoma.

Esthesioneuroblastomas are uncommon neoplasms of the superior nasal cavity originating from olfactory epithelium. High resolution CT features of this neoplasm have not been well studied. Nine cases of esthesioneuroblastoma were reviewed to evaluate findings on high resolution CT. Homogeneous soft tissue masses with relatively uniform enhancement centered in the superior nasal cavity are characteristic. Bony erosion is frequent and usually accompanied by molding of bone. Staging, determined by extension and critical for treatment decisions, is well evaluated by CT.

Adult↗
PubMed1989

Perivascular color artifact: pathologic significance and appearance on color Doppler US images.

A distinctive type of artifactual extravascular assignment of color was identified in 49 color Doppler ultrasound (US) examinations in 43 patients. This artifact appeared as a random localized mixture of red and blue assigned to perivascular soft tissues; the artifact varied with the cardiac cycle, being most prominent in systole and absent or less prominent in diastole. The artifact was seen in 26 patients (32 examinations) at an anastomotic site or stenotic lesion associated with surgically created arteriovenous fistulas for hemodialysis. It was also observed in ten patients with accidental iatrogenic arteriovenous fistulas (renal transplant [n = 6], femoral artery [n = 3], and iliac artery [n = 1]), five with stenotic arteries not associated with arteriovenous fistulas, and two with arterial aneurysms. The authors believe this artifact reflects perivascular tissue vibration caused by turbulent intravascular blood flow. If properly recognized and accurately interpreted, the artifact can be a valuable color Doppler US sign of underlying vascular abnormality.

Aneurysm↗
PubMed1989

Color Doppler ultrasound imaging of lower-extremity venous disease.

A color Doppler ultrasound imaging device was used to evaluate 475 patients with suspected lower-extremity venous thrombosis. Occlusive and nonocclusive femoral and popliteal thrombi were detected in 200 studies (42%). In phase 1 of the study (240 examinations), peripheral augmentation with the use of periodic calf compression was required to show color flow throughout the femoropopliteal venous segment. In phase 2 (235 examinations), with a software upgrade to enhance detectability of slow flow, spontaneous flow could be appreciated in the normal, partly thrombosed, and recanalized femoral popliteal veins without augmentation. Augmentation was often necessary to view tibioperoneal veins. Of the total study group, conventional venography was performed for correlation in 47 patients. In the other patients, clinicians relied on the color Doppler test for the definitive diagnosis of the presence or absence of femoral popliteal venous thrombosis and treated these patients on the basis of the color Doppler test result. In the femoral veins, color Doppler studies and venography agreed in all 12 positive and 35 negative cases. In the popliteal veins, there was agreement in five isolated popliteal thromboses and in 10 femoral popliteal thromboses; there were two false-negative color Doppler studies of isolated popliteal thromboses. In four patients, Doppler studies detected nonocclusive thrombus not evident on venography. Color Doppler imaging is easy to perform and does not require augmentation to view color flow in the femoropopliteal venous segment. Eccentric thrombus and partially canalized thrombus can be shown. Initial experience suggests color Doppler imaging may be useful in the detection of tibioperoneal venous thrombosis.

Femoral Vein↗
PubMed1988

Neovascularity in venous extension of renal cell carcinoma: CT and arteriographic evaluation.

Renal cell carcinoma with venous extension can be evaluated preoperatively using computerized tomography, venography, arteriography, sonography, and magnetic resonance imaging. The spectrum of venous involvement ranges from bland thrombus to tumor with neovascularity. With CT imaging, bland thrombus or tumor thrombus without vivid neovascularity will show a central area of decreased attenuation. Using CT with intravenous bolus technique, thrombus with neovascularity will show attenuation that is isodense with the viable portions of the tumor. This appearance represents the venous extension of tumor thrombus containing a rich bed of neovascularity.

Carcinoma, Renal Cell↗
PubMed1987

A small viral RNA is required for in vitro packaging of bacteriophage phi 29 DNA.

A small RNA of Bacillus subtilis bacteriophage phi 29 is shown to have a novel and essential role in viral DNA packaging in vitro. This requirement for RNA in the encapsidation of viral DNA provides a new dimension of complexity to the attendant protein-DNA interactions. The RNA is a constituent of the viral precursor shell of the DNA-packaging machine but is not a component of the mature virion. Studies of the sequential interactions involving this RNA molecule are likely to provide new insight into the structural and possible catalytic roles of small RNA molecules. The phi 29 assembly in extracts and phi 29 DNA packaging in the defined in vitro system were strongly inhibited by treatment with the ribonucleases A or T1. However, phage assembly occurred normally in the presence of ribonuclease A that had been treated with a ribonuclease inhibitor. An RNA of approximately 120 nucleotides co-purified with the phi 29 precursor protein shell (prohead), and this particle was the target of ribonuclease action. Removal of RNA from the prohead by ribonuclease rendered it inactive for DNA packaging. By RNA-DNA hybridization analysis, the RNA was shown to originate from a viral DNA segment very near the left end of the genome, the end packaged first during in vitro assembly.

Bacillus subtilis↗
PubMed1986

Future Fit: a cardiovascular health education and fitness project in an after-school setting.

Future Fit was developed to provide a low cost, heart health education and fitness program that could be incorporated readily into existing after-school programs with minimal teacher training and nominal expenditures for equipment and supplies. Participants in the 12-week demonstration project were 55 third and fourth grade students enrolled in after-school programs at four sites, randomly assigned to experimental and control conditions. Results indicated significant knowledge gains and changes in knowledge, attitude, and behavior at home. These outcomes suggest health and fitness programming in the after-school setting can be an effective complement to the education provided within the school setting.

Attitude to Health↗
PubMed1985

Lobar collapse with respiratory syncytial virus pneumonitis.

In a study of 30 children with uncomplicated respiratory syncytial virus (RSV) pneumonias, a high incidence of lobar collapse (8/30-26%) was noted. This involved the right upper lobe in seven patients and the left upper lobe in one patient. It is probably attributable to anatomical predispositions, sloughing of necrotic epithelium, and stimulation of mucus production. Lobar collapse should be considered part of the spectrum of RSV pneumonitis.

Female↗