Empirical transfusion strategies for major hemorrhage in trauma patients: A systematic review.

Background: Major hemorrhage is a significant cause of mortality and morbidity around the world. There is currently no consensus on the best empirical transfusion strategy. The current National Institute for Clinical Excellence (NICE) guidelines suggest a ratio of 1:1 of red blood cells and plasma.

Expression of transforming growth factor alpha (TGF alpha) in breast cancer.

Transforming growth factor alpha (TGF alpha) is one growth factor that has been circumstantially implicated in regulating the autocrine growth of breast cancer cells. Expression of TGF alpha can be modulated by activated cellular protooncogenes such as ras and by estrogens. For example, the epidermal growth factor (EGF)-responsive normal NOG-8 mouse and human MCF-10A mammary epithelial cell lines can be transformed with either a point-mutated c-Ha-ras protooncogene or with a normal or point-mutated c-neu (erbB-2) protooncogene.

Transforming growth factor-alpha expression is enhanced in human mammary epithelial cells transformed by an activated c-Ha-ras protooncogene but not by the c-neu protooncogene, and overexpression of the transforming growth factor-alpha complementary DNA leads to transformation.

MCF-10A cells are a spontaneously immortalized normal human mammary epithelial cell line. MCF-10A cells were transfected with two expression vector plasmids containing either a human point-mutated c-Ha-ras protooncogene or the rat c-neu protooncogene. c-Ha-ras-transfected MCF-10A cells grow as colonies in soft agar, exhibit a 3- to 4-fold increase in their growth rate in serum-free medium, and show a reduced mitogenic response to exogenous epidermal growth factor (EGF) or transforming growth factor-alpha (TGF alpha) as compared to MCF-10A cells.

Isolation of a new class of 'flat' revertants from ras-transformed NIH3T3 cells using cis-4-hydroxy-L-proline.

A new class of nontransformed revertant cells has been isolated from the ras-transformed cell line DT using cis-4-hydroxy-L-proline (CHP) as a selective agent. The new revertants, CHP 9CJ and CHP CB4, each contain two copies of the v-Ki-ras gene, elevated levels of phosphorylated p21ras protein, and rescuable transforming virus, indicating that the revertant phenotype observed in these cells does not result from inactivation of v-Ki-ras or inhibition of its expression. Both CHP 9CJ and CHP CB4 revertants show a greatly reduced ability to form colonies in soft agar and to produce tumors in syngeneic mice.

Development of a retroviral vector for inducible expression of transforming growth factor beta 1.

A retroviral vector system for the expression of exogenous genes under the control of an inducible promoter was developed. By utilizing this system, the cDNA for human transforming growth factor beta 1 (TGF-beta 1) was inserted into a retroviral vector under the control of an internal mouse metallothionein promoter and introduced via infection into normal rat kidney fibroblasts (NRK-49F) and epithelial cells (NRK-52E), Chinese hamster ovary cells (CHO), and the human monocytic cell line U937. Control of TGF-beta 1 expression, achieved by Cd2+ induction of vector-encoded TGF-beta 1 mRNA, was cell line specific and resulted in a concomitant increase in neutralizable TGF-beta 1 production by the cells.

Does leukotriene C4 mediate hypoxic vasoconstriction in isolated ferret lungs?

To evaluate leukotriene (LT) C4 as a mediator of hypoxic pulmonary vasoconstriction, we examined the effects of FPL55712, a putative LT antagonist, and indomethacin, a cyclooxygenase inhibitor, on vasopressor responses to LTC4 and hypoxia (inspired O2 tension = 25 Torr) in isolated ferret lungs perfused with a constant flow (50 ml.kg-1.min-1).

Infection with a TGF-alpha retroviral vector transforms normal mouse mammary epithelial cells but not normal rat fibroblasts.

A cDNA clone of human transforming growth factor alpha (TGF-alpha) was introduced into two different retroviral vectors under the transcriptional control of either the viral LTR, vector 1520, or an internal mouse metallothionein-1 promoter, vector 1522. Infection of normal rat kidney fibroblasts (NRK-49F) and mouse mammary epithelial cells (NOG-8), followed by selection, allowed isolation of individual colonies expressing human TGF-alpha. NRK-49F and NOG-8 1520 infectants conditioned their media with equivalent amounts of TGF-alpha protein but responded differently to autocrine stimulation.

Age-dependent effects of indomethacin on hypoxic vasoconstriction in neonatal lamb lungs.

Although smooth muscle is abundant in the pulmonary vessels of young animals at birth, it is not clear if these vessels respond more vigorously to hypoxia than the less muscular vessels of older neonates. To determine the effect of age on the pulmonary vascular response to hypoxia during the neonatal period in a single species, we measured the steady-state stimulus-response relationship between inspired oxygen tension (200, 50, 30 and 0 mm Hg) and pulmonary artery pressure-flow curves in isolated blood perfused lungs from 2- to 4- and 12- to 14-day-old lambs. Hypoxic vasoconstriction was attenuated in the younger newborns at an inspired oxygen tension of 50 mm Hg, but not at the other oxygen tensions.

Effects of cyclo- and lipoxygenase inhibitors on hypoxic vasoconstriction in isolated ferret lungs.

To evaluate the role of leukotrienes in hypoxic pulmonary vasoconstriction, we measured steady-state pressor responses to graded hypoxia in isolated ferret lungs perfused with autologous blood containing 0.001, 0.03, 1, or 3 mM nordihydroguaiaretic acid (NDGA), 1 mM BW 755C, or 0.

Effects of arterial ligation and embolization on pulmonary vascular pressure distribution.

The effects of embolization on the longitudinal distribution of pulmonary vascular pressures with respect to vascular compliance were determined by the vascular inflow and outflow occlusion technique in isolated blood-perfused pig lungs treated with papaverine to prevent vasomotor responses. Embolization with microspheres having mean diameters of 75, 200, and 550 microns and with barrier beads (2 X 3 X 3.5 mm) significantly increased the pressure gradient across the relatively compliant middle region (delta Pm) without increasing the gradients across the relatively noncompliant regions on the arterial (delta Pa) or venous (delta Pv) ends of the vasculature.

Effects of indomethacin on estradiol-induced attenuation of hypoxic vasoconstriction in lamb lungs.

To determine whether cyclooxygenase products mediated the attenuation of hypoxic pulmonary vasoconstriction induced by estradiol, we measured pulmonary arterial pressure at a flow of 50 ml X min-1 X kg-1 (Ppa50) during steady-state exposures to inspired O2 tensions (PIO2) between 0 and 200 Torr in isolated lungs of juvenile ewes. Intramuscular estradiol (10 mg) 44-60 h before study significantly decreased perfusate concentrations of 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), the stable metabolite of the pulmonary vasodilator, prostacyclin, but did not significantly affect the stimulus-response relationship between PIO2 and Ppa50. Estradiol (20 mg) 3-5 days before study increased 6-keto-PGF1 alpha concentrations and decreased Ppa50 at PIO2 of 10, 30, and 50 Torr.

Sequences upstream from the mouse c-mos oncogene may function as a transcription termination signal.

A region upstream from the mouse c-mos proto-oncogene, termed upstream mouse sequence (UMS), prevents expression of mos transforming activity. Previous studies suggested that the UMS prevented transcription readthrough. In this study, we constructed a recombinant DNA clone, pHTS3MS, with the UMS inserted downstream from both the mos gene and a truncated long terminal repeat containing only the U3 enhancer region.

Mouse c-mos oncogene activation is prevented by upstream sequences.

Although the molecularly cloned mouse c-mos oncogene locus can be efficiently activated by insertion of a retroviral long terminal repeat (LTR) 5' to its coding region, only low-frequency transformation occurs with the LTR element inserted 3' to this region. Analysis of several of the latter transformed cell lines suggested that loss of 2 kilobases (kb) of normal mouse DNA sequences preceding c-mos was required for oncogene activation. The determination of the transforming potential of deletion mutants containing only portions of this region followed by analysis of their nucleotide sequences identified a region termed upstream mouse sequence (UMS) as a cis-acting locus that prevents c-mos activation by a 3' LTR.

Long terminal repeat enhancement of v-mos transforming activity: identification of essential regions.

The transforming efficiency of recombinant DNA clones containing the Moloney sarcoma virus v-mos sequence was enhanced by introducing the Moloney sarcoma virus long terminal repeat (LTR) in either the 5' or 3' position relative to v-mos. We analyzed the polyadenylated RNA expressed in cells transformed by these recombinant DNA clones and examined the structural integrity of integrated copies of the DNA. In each case, we demonstrated the presence of v-mos containing RNA transcripts in the polyadenylated RNA and showed that these RNA transcripts are consistent with the structure of the transfected DNA.

In vitro methylation of specific regions of the cloned Moloney sarcoma virus genome inhibits its transforming activity.

The transforming activity of cloned Moloney sarcoma virus (MSV) proviral DNA was inhibited by in vitro methylation of the DNA at cytosine residues, using HpaII and HhaI methylases before transfection into NIH 3T3 cells. The inhibition of transforming activity due to HpaII methylation was reversed by treatment of the transfected cells with 5-azacytidine, a specific inhibitor of methylation. Analysis of the genomic DNA from the transformed cells which resulted from the transfection of methylated MSV DNA revealed that the integrated MSV proviral DNA was sensitive to HpaII digestion in all cell lines examined, suggesting that loss of methyl groups was necessary for transformation.

Proteolytic cleavage of VP1 in 'A' particles of coxsackievirus B3 does not appear to mediate virus uncoating by HeLa cells.

'A' particle of Coxsackievirus B3 were generated from native virus by heating and purified by sucrose gradient centrifugation. These particles were found to be similar to 'A' particles formed by elution from cellular receptors of HeLa cells. Electrophoretic analysis of [35S]methionine-labelled 'A' particles revealed that treatment of the particles with chymotrypsin resulted in the cleavage of VP1 and the formation of a cleavage product which migrated between VP2 and VP3.

Persistence of human rhinovirus infectivity under diverse environmental conditions.

The persistence of human rhinovirus type 2 and type 14 infectivity was studied under various laboratory conditions designed to mimic those commonly found in the environment. The effects of temperature, ionic strength, protein content, and evaporation were compared. Both viruses were stable (less than 0.

Stabilization of "A" particles of coxsackievirus B3 by a HeLa cell plasma membrane extract.

Previous studies in our laboratory showed that HeLa cell plasma membranes were recovered from sucrose gradients in two major bands and that the heavier band possessed a putative inhibitor of uncoating of coxsackievirus B3. It has now been found that the mechanism of inhibition is the stabilization of "A" particles against inactivation at 37 degrees C. [3H]uridine-labeled virions converted to A particles by band 4, the heavier band, were four times more stable at 37 degrees C than those produced by band 3.

Survival of coxsackievirus B3 under diverse environmental conditions.

The survival of coxsackievirus B3 was studied under various conditions of incubation. The comparative study demonstrated that coxsackievirus B3 was stable for 24h (less than 0.4-log decrease in titer) when suspended at neutral pH (6 or 23 degrees C) in the presence of 0.