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Biomedical subjects

A Axelrad

Publications and source records attributed to A Axelrad.

13 recordsLinked to original sources

Prospective multicenter trial of esophageal Z-stent placement for malignant dysphagia and tracheoesophageal fistula.

BACKGROUND: Conventional esophageal prosthesis placement has been associated with a 6% to 8% perforation rate and numerous postplacement complications. Expandable esophageal stents have been developed to preclude the above but there are few studies that have prospectively defined clinical results and subsequent stent-related complications. METHODS: All patients who underwent esophageal Z-stent placement at nine university or referral hospitals were prospectively assessed. Data collected included patient demographics, acute and subacute placement problems, the ability to occlude airway fistulas, prestent and poststent dysphagia scores, and patient survival. RESULTS: Fifty-four of 56 patients (96%) with refractory dysphagia or malignant esophagoairway fistulae had 73 Z-stents successfully inserted. Initial distal deployment occurred in 13% of the patients and an additional 17% required balloon dilation to achieve maximal diameter. Acute placement complications occurred in 11% of patients and included severe pain (3), bleeding from necrotic tumor (2), and hiatal hernia intussusception (1). No perforations occurred. Eight of 11 patients (73%) had complete tracheoesophageal fistula occlusion and mean dysphagia score (+/- SD) improved from 2.6 (0.7) to 1.1 (1.2) (p < 0.01). Fifteen stents (27%) had delayed migration at a mean of 1 month and 3 required surgery for retrieval. Three patients had ultimate stent erosion resulting in bleeding in 2 (exsanguination 1) or fistula (treated with a conventional stent). CONCLUSIONS: The authors conclude that esophageal Z-stents can be placed safely and successfully in the majority of patients. The tendency of distal deployment during placement and subsequent migration problems at a time distant from placement in a patient subset deserve attention and are currently being addressed.

Adult↗

Can ultrasound replace diagnostic peritoneal lavage in the assessment of blunt trauma?

Diagnostic peritoneal lavage (DPL) and computed tomography (CT) are the primary diagnostic modalities in the evaluation of patients with suspected blunt abdominal trauma (BAT). Diagnostic peritoneal lavage is fast and accurate but associated with complications. Computed tomography is also accurate, yet requires that patients be stable and transportable. A prospective study was designed to determine the utility of emergency ultrasound (US) studies in the initial assessment of BAT. Two hundred acutely injured patients with suspected BAT were evaluated with US. Patients were eligible for the study if they met trauma criteria and had suspected BAT. Subsequently, without knowledge of the US results, DPL or CT was performed. Ultrasound showed a sensitivity of 83%, a specificity of 100%, and an accuracy of 97% in detecting intra-abdominal injuries. Six injuries were missed but only one was felt to be significant. If US had been used in all 200 patients, 199 would have had appropriate care. We conclude US is reliable in the detection of free intraperitoneal fluid and may be used in place of DPL or CT.

Abdominal Injuries↗

Superoxide dismutase specifically inhibits erythroid cell DNA synthesis and proliferation.

The antioxidant enzyme superoxide dismutase (SOD) was previously shown to inhibit both the proliferation of murine erythroid DA-1 cells growing in the presence of Interleukin-3 (IL-3) and the DNA synthesis of marrow erythroid progenitor cells (BFU-E) in vitro. We show here that the inhibition of marrow cell DNA synthesis by SOD is specific for BFU-E and erythroid precursors (CFU-E), with other myeloid progenitors (CFU-GM) and stem cells (CFU-S) being unaffected, and IL-3 blocks the inhibitory effects of SOD on BFU-E in a dose-dependent manner. Extending earlier observations on the effects of SOD on cell proliferation, it was found that SOD was capable of inhibiting DA-1 cell proliferation supported by either IL-3 or erythropoietin (epo), but had no effect on IL-3 dependent FDCP-1 cells, nor on epo-dependent HCD-57 cells. Of several murine erythroleukemia cell lines tested, only those transformed with Friend SFFVa virus were inhibited by SOD, while those transformed with Friend SFFVp or MuLV virus were not affected. These results show that the effects of SOD are not antagonistic to particular growth factors but rather the inhibition is specific for erythroid cells, and cells of the proper stage can be inhibited even if they have been transformed to factor independence.

Cell Differentiation↗

A self-renewing, bipotential erythroid/mast cell progenitor in continuous cultures of normal murine bone marrow.

We have established permanent lines of nonadherent cells from fresh normal mouse bone marrow in media containing pokeweed mitogen-stimulated spleen cell conditioned medium (PWSCM). These lines continuously produced erythropoietic progenitor cells (detected by their ability to form erythroid bursts in semi-solid medium containing erythropoietin) together with cells having characteristics of the mast cell lineage (as demonstrated by metachromatic staining with toluidine blue, histamine content and membrane receptors for IgE). Sixteen such cell lines have been established in sixteen attempts. Cloning experiments were carried out to determine the nature of the progenitor cell(s) responsible for the permanence of these cultures. When cells were cultured in methylcellulose medium containing PWSCM, colonies were observed which reached macroscopic size after 4 weeks of incubation. Replating of individual primary colonies resulted in secondary colony formation, indicating the presence of progenitor cells with self-renewal potential. Forty-seven primary colonies were picked and their cells were suspended in liquid culture medium containing PWSCM. Of these, twenty-one could be expanded to establish permanently growing sublines. Sixteen of these sublines were found to be composed of both erythroid progenitors and mast cells. In five sublines only mast cells could be seen; none of the sublines appeared to be purely erythroid. Karyotypic analysis of mast cells and of erythroid cells of seven sublines derived from individual colonies which arose in cocultures of male and female cells revealed that the mast cells and erythroid cells were both of the same sex in each of the seven sublines; this demonstrates the single cell origin of each colony and of the two lineages derived from it. We conclude that these nonadherent, factor-dependent cell lines are maintained by self-renewal and differentiation of bipotential progenitor cells apparently restricted to the erythroid and mast cell lineages.

Animals↗

[Computed tomography of the heart. Technic for quantitative evaluation of the perfusion of the ischemic myocardial region. Experimental basis].

A CT standard procedure has been developed in six series of experiments, using 62 anaesthetised dogs in order to quantitative relative blood flow through ischaemic heart muscle. Measurements of cardiac dynamics by means of contrast media were less strictly controlled. The use of the standardised procedures with contrast injections is necessary because of the variable perfusion and washout intervals of the contrast in normal and ischaemic myocardium.

Animals↗

A "serum-free" medium for the production of erythropoietic bursts by murine bone marrow cells.

We describe a culture medium that does not require the addition of serum, in which erythropoietic bursts are produced from murine bone marrow cells with efficiencies at least as great as those of serum-containing media. Four ingredients were shown to be essential: bovine serum albumin (BSA), transferrin, cholesterol, and erythropoietin. The system supported burst formation without the addition of conditioned medium as source of burst-promoting factor(s). To include cholesterol in the medium we found that there was no necessity for sonication, nor for subsequent evaporation of the ethanol in which the cholesterol was dissolved. Filtration of cholesterol and delipidation of BSA both impaired the ability of the medium to support burst production. The "serum-free" medium described here, even though not truly defined, is useful for erythropoietic culture: it is reliable, highly efficient in supporting burst formation, and simple and economical to prepare from ingredients readily available from commercial sources without the need for special testing.

Animals↗

Gene controlled negative regulation of DNA synthesis in erythropoietic progenitor cells.

Congenic strains differing by a small segment of Chromosome 9 that bears the Fv-2 locus have provided valuable material for investigating genetic resistance to Friend polycythemia virus (FV). C57BL/6 (B6) (Fv-2rr) mice have been found to differ from B6.S (Fv-2ss) mice not only in their response to this virus but also in the proliferative state of their erythropoietic progenitor cells BFU-E: in B6 mice the majority of BFU-E are normally quiescent, while in B6.S mice approximately 50% are actively synthesizing DNA at any time. We have shown that B6 but not B6.S marrow contains a macromolecule that negatively regulates DNA synthesis specifically of BFU-E in vitro. Evidence is presented that this macromolecule is a physiological negative regulator active in vivo in B6 mice. A new liquid culture system is described in which FV and erythropoietin (epo) act synergistically on Ficoll-Isopaque separated bone marrow cells to give rise after 7 days to large numbers of CFU-E detectable in 2-day plasma cultures with and without epo. Inclusion of concentrated B6 but not B6.S bone marrow supernatant in liquid cultures drastically curtailed the amplification of CFU-E by FV and epo. These studies indicate that both DNA synthesis and the BFU-E stage of differentiation are necessary conditions for initiating the effects of polycythemia-inducing FV. Genetic resistance to FV appears not to reside within the target cells for the virus.

Animals↗