Growth and differentiation of cultured fetal hepatocytes isolated various developmental stages.
(17/2483)
We examined the relationship between cell proliferation and differentiation of cultured rat fetal and newborn hepatocytes isolated from various developmental stages. The albumin production rate increased along with cell growth under in vitro culture and became maximal two days after the growth cessation. AFP was secreted by both fetal and newborn hepatocytes with growth ability. Furthermore, the responses to HGF addition in fetal hepatocyte cultures were observed in terms of growth stimulation and down-regulated of the Met receptor. We also studied the changes in RB and liver enriched transcription factors (C/EBPs) for investigating the mechanism underlying proliferation and differentiation of fetal hepatocytes. Western blot analysis of hepatocytes taken from various gestation stages of rat liver showed that the expression of RB and C/EBP beta increased as gestation stage proceeded. When RB antisense S-oligonucleotide was added to the culture medium, proliferation and AFP expression increased, while C/EBP alpha and albumin expressions decreased. These results indicated that the tumor suppressor gene product RB had a profound role not only in cell proliferation but also hepatocyte differentiation. (+info)
Evaluation of myocardial, hepatic, and renal perfusion in a variety of clinical conditions using an intravenous ultrasound contrast agent (Optison) and second harmonic imaging.
(18/2483)
OBJECTIVE: To assess the potential of intravenous Optison, a second generation ultrasound contrast agent, and various ultrasound imaging modes to determine myocardial, kidney, and liver perfusion in normal subjects and patients with left ventricular dysfunction or chronic pulmonary disease together with renal or hepatic dysfunction. METHODS: Five normal subjects and 20 patients underwent grey scale echocardiographic imaging of myocardium, kidney, and liver during 505 intravenous injections of Optison. Images were assessed qualitatively by two independent observers and quantitatively using video densitometry to determine the peak contrast enhancement effect. RESULTS: Qualitative analysis showed that intermittent harmonic imaging was superior to either conventional fundamental or continuous harmonic imaging for all organs. Quantitative analysis showed that the peak change in echocardiographic intensity v baseline during continuous harmonic imaging was 11 units for myocardium (p < 0.03), 7 units for kidney (NS), and 14 units for liver (p < 0.05). During intermittent harmonic imaging the peak change was significantly greater, being 33 units for myocardium (p < 0.0001), 24 units for kidney (p < 0.0002), and 16 units for liver (p < 0.001). CONCLUSIONS: Organ tissue perfusion can be demonstrated following intravenous injection of Optison, particularly when used in combination with intermittent harmonic imaging techniques. This contrast agent is effective in a variety of clinical conditions. (+info)
Purification and some properties of a medium-chain acyl-thioester hydrolase from lactating-rabbit mammary gland which terminates chain elongation in fatty acid synthesis.
(19/2483)
1. An acyl-thioester hydrolase was isolated from the cytosol of lactating-rabbit mammary gland. The purified enzyme terminates fatty acid synthesis at medium-chain (C8:0-C12:0) acids when it is incubated with fatty acid synthetase and rate-limiting concentrations of malonyl-CoA. These acids are characteristic products of the lactating gland. 2. The mol.wt. of the enzyme is 29000+/-500 (mean+/-S.D. of three independent preparations), as estimated by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. 3. The enzyme also hydrolyses acyl-CoA esters of chain lengths C10:0-C16:0 when these are used as model substrates. The greatest activity was towards dodecanoyl-CoA, and the three preparations had specific activities of 305, 1130 and 2010 nmol of dodecanoyl-CoA hydrolysed/min per mg of protein when 56muM substrate was used. 4. The way in which this enzyme controls the synthesis of medium-chain fatty acids by fatty acid synthetase is briefly discussed. (+info)
Osmotic pressure contribution of albumin to colloidal interactions.
(20/2483)
Two surfaces that come in close contact in a solution with macromolecules present experience an attractive force caused by the osmotic pressure. We present a measurement of this effect by using a micrometer-sized sphere bound to a flat plate through a single molecular attachment in an albumin-containing solution. We obtain the osmotic part of the interaction potential with a resolution of <1 nm and a fraction of kTroom. This attractive interaction is seen to have a range comparable to the size of the albumin molecule. The results are broadly in agreement with a geometric model first proposed by Asakura and Oosawa. (+info)
Ultrasonographic arterial portography with second harmonic imaging: evaluation of hepatic parenchymal enhancement with portal venous flow.
(21/2483)
Ultrasonographic arterial portography was evaluated with second harmonic and conventional gray scale imaging after the administration of 0.001 to 0.1 ml/kg of FS069 (Optison) in 10 dogs (four dogs with ligation of the portal vein branch) and two woodchucks with hepatocellular carcinomas. Harmonic imaging was required to obtain good liver parenchymal enhancement for ultrasonographic arterial portography to be useful. The tumors were visible as regions of greater enhancement after intravenous injection and as hypoechoic regions after superior mesenteric artery injection. The segments with portal vein ligation were not detected after intravenous injection but were clearly seen after superior mesenteric artery injection. Doppler signal measurement verified a significant difference between the portal vein and hepatic vein after superior mesenteric artery injection and in the femoral artery after intravenous versus superior mesenteric artery injection, demonstrating that minimal levels of FS069 pass through the liver. (+info)
Induction of monocyte chemoattractant protein-1 by albumin is mediated by nuclear factor kappaB in proximal tubule cells.
(22/2483)
The transcription and translation of monocyte chemoattractant protein-1 (MCP-1), a CC chemokine, are increased in proximal tubule epithelial cells (PTC) stimulated with pathophysiologically relevant concentrations of albumin. The purpose of this study was to investigate whether nuclear factor kappaB (NFkappaB)/Rel proteins play a role in albumin-induced MCP-1 transcription. Confluent monolayers of rat PTC in primary culture were stimulated with delipidated bovine serum albumin. NFkappaB, the NFkappaB inhibitory protein (IkappaB), and MCP-1 transcription were assessed using electrophoretic mobility shift assays, Western immunoblotting, semiquantitative reverse transcription-PCR, and ribonuclease protection assays. Activation of NFkappaB by delipidated bovine serum albumin (15 mg/ml) was detectable within 2 h, maximal after 8 h, and maintained for at least 16 h of continuous exposure. Supershift analysis showed that the activated proteins were composed of p50/p50, p50/p65, and p50/c-Rel dimers. dimers. Cytoplasmic IkappaBalpha levels were decreased 30 min after stimulation and returned to unstimulated levels by 4 to 8 h. IkappaBbeta levels were decreased at 2 h and there was no recovery until 8 h. Inhibition of NFkappaB with pharmacologic agents (N-tosyl-phenylalanine chloromethyl ketone and dexamethasone) and an antisense oligonucleotide to the rat p65 subunit of NFkappaB significantly reduced MCP-1 transcription. The 3.6-kb 5' flanking region of the rat MCP-1 gene was cloned and sequenced, and two putative kappaB binding sites were identified within the enhancer region. Therefore, albumin increased NFkappaB and reduced IkappaB levels in PTC, and MCP-1 expression was dependent on NFkappaB activation. It is concluded that the activation of NFkappaB/Rel proteins modulates chemokine production in PTC in response to albumin and is likely to have an important role in the mediation of tubulointerstitial injury in proteinuric renal disease. (+info)
Effect of intravenous saline, albumin, or hydroxyethylstarch on blood volume during combined ultrafiltration and hemodialysis.
(23/2483)
It is generally advocated to use saline or albumin infusions during symptomatic hypotension during dialysis. However, because of their side effects and/or costs, they are of limited use. Hydroxyethylstarch (HES), a synthetic colloid with a long-standing volume effect, is used in the management of hypovolemia. In this study, the efficacy of three fluids (isotonic saline [0.9%], albumin [20%], and HES [10%]) was assessed during three treatment sessions with combined ultrafiltration and hemodialysis, which differed in the type of fluid given intravenously. Changes in relative blood volume (BV), systolic BP (SBP), and vascular reactivity (venous tone [VT]) were compared. An intravenous infusion of 100 ml of fluid was given when the decrease in BV versus baseline was more than 10% as measured by a continuous optical reflection method. The ultrafiltration was continued. BV decreased significantly versus baseline independent of the intravenous fluid administration in all three treatment sessions. However, when we compared BV values at the end of the dialysis session with those at the time of infusion, BV continued to decrease significantly with saline (change in BV -4.56 +/- 2.75%; P < 0.05) and albumin (change in BV -2.13 +/- 2.51%; P < 0.05), but not with HES (change in BV -0.15 +/- 2.17%; NS). Between albumin and HES there were no significant differences in changes in BV (NS), whereas between HES and saline (P < 0.05) and between albumin and saline (P < 0.05) the differences in BV changes were significant. SBP remained unchanged within each session. Although SBP tended to decrease more with saline compared to albumin and HES, the difference was not significant. The higher decrease in BV and SBP with saline was counterbalanced by a significantly higher increase in VT, while VT remained unchanged in the other two sessions. It is concluded that HES is a promising fluid in preserving blood volume, comparable to albumin, but superior to saline. (+info)
Soluble intercellular adhesion molecule-1 in the bronchoalveolar lavage fluid of normal children exposed to parental cigarette smoke.
(24/2483)
This study sought to test the hypothesis that normal children exposed to parental cigarette smoke have increased bronchoalveolar lavage (BAL) fluid levels of soluble intercellular adhesion molecule (sICAM)-1. Cells and solutes from the lower airway of normal children were obtained by nonbronchoscopic BAL using three aliquots of 1 mL x kg body weight(-1) normal saline, prior to elective orthopaedic surgery. Children with evidence of recent or ongoing infection, atopic disease, previous history of wheeze, and chronic respiratory symptoms were excluded. Twelve children with parents who smoked (group 1) were paired with 12 age- and weight-matched controls with self-reported nonsmoking parents (group 2). There was no significant difference (group 1 versus 2) in the volume of BAL fluid recovered (median 29.0 versus 28.7 mL), the percentage of alveolar macrophages (92.5 versus 91.8%), neutrophils (1.1 versus 2.1%), lymphocytes (5.3 versus 5.6%) and eosinophils (0 versus 0%), and the total BAL fluid leukocyte concentration (80 versus 61 x 10(3) cells x mL(-1)). BAL fluid albumin concentration was similar between the two groups (0.033 versus 0.020 mg x mL(-1)). sICAM-1 was detected in all BAL fluid samples, and was significantly increased in group 1 (39.2 versus 22.5 ng x mL(-1), p<0.01). It was concluded that exposure of children to parental cigarette smoke is associated with increased soluble intercellular adhesion molecule-1 concentrations in the bronchoalveolar lavage fluid and this may reflect an altered activation of pulmonary immune cells. (+info)