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Biomedical subjects

S C Henderson

Publications and source records attributed to S C Henderson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Dynamic organization of DNA replication in mammalian cell nuclei: spatially and temporally defined replication of chromosome-specific alpha-satellite DNA sequences.

Five distinct patterns of DNA replication have been identified during S-phase in asynchronous and synchronous cultures of mammalian cells by conventional fluorescence microscopy, confocal laser scanning microscopy, and immunoelectron microscopy. During early S-phase, replicating DNA (as identified by 5-bromodeoxyuridine incorporation) appears to be distributed at sites throughout the nucleoplasm, excluding the nucleolus. In CHO cells, this pattern of replication peaks at 30 min into S-phase and is consistent with the localization of euchromatin. As S-phase continues, replication of euchromatin decreases and the peripheral regions of heterochromatin begin to replicate. This pattern of replication peaks at 2 h into S-phase. At 5 h, perinucleolar chromatin as well as peripheral areas of heterochromatin peak in replication. 7 h into S-phase interconnecting patches of electron-dense chromatin replicate. At the end of S-phase (9 h), replication occurs at a few large regions of electron-dense chromatin. Similar or identical patterns have been identified in a variety of mammalian cell types. The replication of specific chromosomal regions within the context of the BrdU-labeling patterns has been examined on an hourly basis in synchronized HeLa cells. Double labeling of DNA replication sites and chromosome-specific alpha-satellite DNA sequences indicates that the alpha-satellite DNA replicates during mid S-phase (characterized by the third pattern of replication) in a variety of human cell types. Our data demonstrates that specific DNA sequences replicate at spatially and temporally defined points during the cell cycle and supports a spatially dynamic model of DNA replication.

Animals↗
PubMed1991

The effects of an atherogenic diet on macrophage/biomaterial interactions.

We previously reported that biomaterials differentially induced macrophages to secrete growth factors that mediate reendothelialization. The present study evaluates the effect of an atherogenic diet on macrophage/biomaterial interactions. Female New Zealand white rabbits were fed an atherogenic diet. Peritoneal macrophages were harvested from these as well as rabbits fed a normal diet and cultured in Minimum Essential Medium with platelet-poor serum. Dacron or polyglactin 910 were added to two of three conditions of both cell groups in passage 2. Conditioned media were collected weekly through week 15. Mitogenicity assays were performed with quiescent mouse embryonal (BALB/c3T3) fibroblasts, atherosclerotic rabbit aortic smooth muscle cells, and murine capillary lung (LE-II) endothelial cells. Mitogenic activity was assayed by scintillation counting of tritiated thymidine incorporation into deoxyribonucleic acid (DNA). Results showed increased mitogenic activity released by macrophages from atherosclerotic rabbits, in the absence of prosthetic material, when assayed against every cell line. In normal diet macrophages, polyglactin 910 stimulated mitogen release for every cell line, and Dacron yielded minimal mitogen release. In lipid diet macrophages polyglactin 910 slightly increased mitogen release for all three cell lines, whereas Dacron resulted in stimulation of DNA synthesis in smooth muscle cells and BALB/c3T3 cells but less DNA synthesis in LE-II cells than in control, no graft material, media. Western blotting demonstrated immunoreactivity to basic fibroblast growth factor in media from normal diet macrophages but only in the presence of polyglactin 910 or Dacron. Radioimmunoassay for platelet-derived growth factor B chain was negative in all groups, and polymerase chain reaction techniques to amplify transforming growth factor-beta messenger ribonucleic was negative. These data demonstrate the effect of in vivo dietary manipulation on macrophage activation as well as the effect of an atherogenic diet in modulating macrophage/biomaterial interactions. Additionally, different biomaterials differentially induce macrophages to release factors that stimulate and inhibit growth.

Animals↗
PubMed1989

Hemodynamic effects on endothelial cell monolayer detachment from vascular prostheses.

The establishment of an early blood-contacting endothelialized surface may improve the graft-host relationship. This study evaluated the adherence of indium 111-radiolabeled endothelial cells that were cultured to confluence on fibronectin-treated polyester elastomer (Hytrel) grafts that were perfused for two hours on a pulse duplicator apparatus under high- and low-shear conditions. Perfusate samples were serially assayed for radioactivity. After perfusion, grafts were sectioned into four segments and assayed for retained radioactivity. All graft segments were hematoxylin stained and examined under light microscopy for evaluation of cell density. Excellent endothelial cell adherence (90%) was observed under both hemodynamic conditions at 120 minutes, with most losses occurring within the first 15 minutes. No differences were seen between high- and low-shear conditions or proximal vs distal graft segments.

Animals↗
PubMed1982

Unsuspected adnexal masses in renal transplant recipients.

Post-transplant sonograms in 74 female recipients less than 40 years old revealed unsuspected adnexal masses in 5 (7 per cent). Sonographically, these masses were difficult to distinguish from other post-transplant fluid collections, such as lymphoceles, urinomas or abscesses and, consequently, led to further diagnostic evaluations in 4 patients. Of the adnexal masses 4 were excised surgically: 2 were hemorrhagic ovarian cysts, 1 was a follicular ovarian cyst and 1 was a paraovarian cyst. A coexisting gynecologic mass should be included in the differential diagnosis of a perinephric mass in female transplant recipients. Pre-transplant sonograms to identify or exclude occult pelvic masses in women may be of benefit in simplifying the postoperative management and minimizing unnecessary diagnostic evaluation.

Adnexal Diseases↗
PubMed1980

Percutaneous aspiration biopsy of renal allografts using ultrasound localization.

Percutaneous aspiration of renal allografts was done employing ultrasound localization and the Jamshidi renal biopsy needle-syringe. Adequate tissue for pathologic assessment was obtained in 19 of 20 biopsy attempts. There were no complications. Ultrasound provides a convenient, nonradiologic means of renal localization for allograft biopsy. The aspiration needle-syringe is well suited for percutaneous transplant biopsy.

Biopsy, Needle↗
PubMed1978

Ultrasound findings of renal angiomyolipoma.

Angiomyolipoma (AML) IS A BENIGN RENAL NEOPLASM. Preoperative diagnosis is important because of the different surgical approaches to benign and malignant tumors. Angiographic findings of AML and renal carcinoma may be similar and differentiation difficult. B-mode ultraslund examination of AML demonstrates a different image pattern which may be helpfou in differentiation.

Adolescent↗
PubMed1977

Intravenous renal angiography revisited.

A non-catheter technique to visualize the renal arteries during conventional excretory urography is re-emphasized. By rapid injection of the contrast agent and immediate filming satisfactory visualization can be obtained in many cases. This technique is useful in the evaluation of vascular impressions and other urographic findings when intra-arterial catheter examination is not indicated.

Angiography↗
PubMed1977

Ultrasound diagnosis of common bile duct dilatation.

The use of ultrasound in the differential diagnosis of obstructive jaundice has been previously reported. Although common bile duct dilatation has been demonstrated, criteria for its accurate identification have not been stressed. This report describes findings and relationships helpful in recognition of a dilated common bile duct. It is important to identify this structure, since it could otherwise be confused with surrounding vessels.

Adenocarcinoma↗
PubMed1977

Ultrasonic aortography: unexpected findings.

In a series of 125 patients examined ultrasonically for suspected abdominal aortic aneurysms, 15 patients (12%) had intraabdominal abnormalities unrelated to the aorta. In 12 of these patients, a retroperitoneal malignancy clinically mimicked an aneurysm. In the remaining three, other abnormalities were discovered in addition to an aneurysm. In one patient, a large uterine myoma was visualized; in another, large retroperitoneal lymph nodes subsequently proved to be lymphoma; in the third, enlarged lymph nodes in association with a carcinoma of the colon were discovered. Because of the high incidence of unsuspected findings, ultrasonography should become an essential part of the evaluation of this group of patients.

Aged↗
PubMedDate not supplied

Platelet interactions with heparin binding growth factor and fibronectin.

A fibronectin (Fn)/heparin/heparin binding growth factor (HBGF)/heparin (FHHH) complex can be affixed to vascular grafts. This study examines the effect of HBGF, Fn, and FHHH on platelet adhesion and aggregation. Expanded polytetrafluoroethylene (PTFE) grafts (5 cm X 4 mm) were treated with Fn (n = 9), FHHH (n = 9), or neither (n = 10) and interposed into canine aortoiliac systems, using each dog as its own control. Autogenous radiolabeled (111In oxine-650 muCi) platelets were injected IV prior to re-establishment of circulation. Blood flow was determined by electromagnetic flowmetry and perfusion maintained for 30 min. Grafts were removed with native aorta and ipsilateral iliac arteries (IIA). Specimens, excluding anastomoses, were sectioned for gamma counting and computerized planimetry. Results showed that FHHH and Fn treated grafts contained significantly more radioactivity than control segments, when normalized to their IIA. FHHH treated grafts contained 27 +/- 16 times more radioactivity per mm2 than IIA, Fn treated prostheses 12 +/- 8 times more, and untreated PTFE 4 +/- 3 times more. FHHH was significantly more radioactive than Fn alone (p less than or equal to 0.03). Platelet aggregation in response to either Fn or HBGF was studied in vitro. Aggregation was not activated by either Fn (1-100 micrograms/100 microliters) or HBGF (25-2,500 ng/100 microliters). These data suggest that Fn and HBGF promote platelet adhesion but not aggregation.

Animals↗
PubMedDate not supplied

Albumin impregnated vascular grafts: albumin resorption and tissue reactions.

This study aimed to determine the kinetics of albumin resorption from and the healing of two types of albumin impregnated Vasculour II (Bard Cardiovascular) Dacron grafts (ACG-A and ACG-B) using whole blood preclotted Vasculour II Dacron grafts (without albumin) as controls (PCC). Prostheses measuring 4 mm ID x 50 mm length were implanted in the aortoiliac position in 24 dogs (ACG-A n = 12, ACG-B n = 24, PCC n = 12) and explanted after 1, 2 4, and 6 months. Platelet count, platelet aggregometry to 10(-5) M ADP, prothrombin time (PT), and partial thromboplastin time (PTT) were determined preoperatively and at explantation. Sections of the explanted grafts were assayed for human albumin by immunohistochemical techniques utilizing a rabbit polyclonal mono-specific antibody for human albumin followed by the addition of a biotinylated goat anti-rabbit IgG. Immunoperoxidase staining was then performed using Avidin D horse-radish peroxidase. Histology of the grafts (light microscopy, scanning electron microscopy, and transmission electron microscopy) as well as percent thrombus free surface area (TFSA) by computerized planimetry were also determined. Seven of 48 grafts were occluded (85.4% patency) with no difference among the three groups. Platelet aggregometry was not predictive of graft patency. No change in PT or PTT occurred nor was there any difference among the three groups. Retained albumin was detected in every one-month explant but not beyond that time, with the sensitivity for detecting human albumin in this assay being 20 mg albumin per gram of Dacron. All ACG explants at one month revealed inner capsular fibrin coagula not present in PCC specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗