Biomedical subjects

F Moller

Publications and source records attributed to F Moller.

13 recordsLinked to original sources

PubMed1993

Cellular mechanisms underlying differential rejection of sequential heart and lung allografts in rats.

As the simultaneous transplantation of two or more organs into a single recipient has become increasingly common, asynchronous allograft rejection has become an important clinical problem. To investigate the cellular and molecular mechanisms underlying differential organ rejection, we developed a rat model in which heart and lung allografts were transplanted sequentially. Heterotopic heart allografts transplanted into DA recipients from PVG donors survived indefinitely if the recipients were given a short course of rabbit antirat thymocyte globulin or cyclosporine at the time of transplantation. In contrast, orthotopic left lungs transplanted under the same conditions were rejected in ATG-treated recipients and accepted in most CsA-treated recipients. These animals were then given a second organ allograft from the same strain or a third party to assess whether they exhibited donor specific tolerance and whether the acceptance or rejection of the first allograft would influence the survival of the second transplant. Animals tolerized to a heart allograft with ATG rejected an orthotopic lung transplant from the same strain as the original allograft, whereas recipients treated with CsA at the time of their heart transplant accepted a subsequent lung graft. Surprisingly, animals treated with either ATG or CsA that had rejected a lung allograft accepted a subsequent heart transplant. Using limiting dilution analysis and adoptive transfer studies, we found that some recipients had developed suppressor cells while others demonstrated anergy. We conclude that major histocompatibility complex antigens as well as other antigens are involved in the differential rejection of heart and lung allografts.

Animals↗

PubMed1993

Optimizing alveolar expansion prolongs the effectiveness of exogenous surfactant therapy in the adult rabbit.

We evaluated four ventilator patterns after the administration of 80 mg/kg bovine lipid extract surfactant (LES) to anesthetized, paralyzed, saline-lavaged New Zealand white rabbits. Two ventilator types were compared: high frequency oscillatory ventilation (HFO) versus conventional mechanical ventilation (CMV), each at high (HI) and low (LO) end-expiratory lung volumes (EELV); n = 6, each group; treatment duration = 4 h. Target PaO2 ranges were > 350 mm Hg for groups with high EELV (i.e., HFO-HI and CMV-HI) and 70 to 100 mm Hg for those with low EELV (i.e., HFO-LO and CMV-LO). Ventilator pressures were limited to < or = 39/9 cm H2O in the CMV-HI group. Five of six CMV-HI-treated animals did not maintain target PaO2 levels. Both ventilator type and strategy influenced outcome significantly. Animals managed with HFO had higher mean arterial pressures (p = 0.004), lower mean airway pressures (Paw) (p < 0.00008) and HCO3- requirements (p < 0.02), larger inflation (p = 0.003) and deflation (p < 0.00001) respiratory system volumes at 10 cm inflation pressure, and higher lung lamellar body (p = 0.0006) and lavage fluid (p = 0.003) phospholipid quantities than did CMV-treated animals. The deflation P-V curve (p = 0.0004), lamellar body (p < 0.00001) and lavage fluid (p = 0.0002) phospholipid levels were superior after the high EELV strategy. We conclude that ventilator pattern strongly influences exogenous surfactant efficacy. Benefits arise from keeping EELV high enough to prevent atelectasis and using small (approximately 2 ml/kg) tidal volumes to prevent overdistension.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1986

A double-blind placebo-controlled trial of progesterone vaginal suppositories in the treatment of premenstrual syndrome.

Rigorous criteria were used to select women with severe premenstrual syndrome for inclusion in an 8-month double-blind placebo-controlled clinical trial of progesterone vaginal suppositories. Following a control month without treatment, progesterone (200 mg in polyethylene glycol base) or placebo was self administered twice daily by vaginal suppository for a minimum of 12 days before the onset of menstruation for 3 months. Crossover to the opposite medication for a further 3 months was followed by a final control cycle without treatment in month 8. Physician contact was minimized throughout the study to avoid any possible positive effects of psychological support which may have confounded past investigations. Detailed self-report questionnaires were completed every 3 days for the duration of the study. Although the attrition rate was high, 20 women completed the trial and their records are analyzed here. The results of this trial indicate that the response to vaginal progesterone in these dosages is, at best, marginal and not significantly different from response with placebo use.

Adolescent↗

PubMed1983

The influence of specific phospholipids on the interaction of hexokinase with the outer mitochondrial membrane.

Repeated washing of a brain mitochondrial fraction results in a progressive decrease in the proportion of mitochondrially bound hexokinase that can be solubilized during a subsequent incubation with glucose-6-phosphate (glucose-6-P). Phospholipids removed during the washing procedure can be added back to washed mitochondria, resulting in enhancement of the solubilization by glucose-6-P. Column and thin-layer chromatographic methods have been used to isolate and identify active phospholipids. Additional studies were performed with purified lipids obtained commercially. Both lysophospholipids and acidic phospholipids were active in enhancing solubilization of hexokinase by glucose-6-P. Phospho-inositides, particularly diphosphoinositide, were quite effective, raising the possibility that the actively metabolized phosphoinositides may be involved in regulation of hexokinase binding in vivo.

Animals↗

PubMed1983

[Colonic occlusions. Retrospective cooperative study of 497 cases].

A retrospective multicenter study involving 12 digestive surgery centers was conducted on 497 cases of colon obstruction. The most frequent cause of colon obstruction was colo-rectal cancer (71 p. cent of cases), but many other etiologies were involved, including 61 cases of torsion and 37 patients with occlusive sigmoiditis. Differential clinical and radiological features in each etiological group are discussed, the results of therapy undertaken analyzed, and a reasonable line of conduct proposed, adapted to each situation, with the objective of attempting to reduce mortality which still affects 25 p. cent of cases operated upon.

Adult↗

PubMed1982

Effect of salts on membrane binding and activity of adipocyte phosphatidate phosphohydrolase.

Isosmotic replacement of sucrose in a low ionic strength homogenizing buffer (0.25 M sucrose/1 mM EDTA/1 mM Tris-HCl, pH 7.4) with KCl increased the microsomal and decreased the soluble phosphatidate phosphohydrolase (EC 3.1.3.4) activity of isolated rat fat cells. At 54 mM KCl the microsomal specific activity was increased 6-fold and the soluble activity was decreased to less than one-third. Binding of enzyme was promoted by KCl and NaCl when the once isolated soluble and microsomal fractions were recombined and incubated at 37 degrees C. Half-maximal binding occurred at about 17 mM salt and maximal binding at about 50 mM. The pH optimum of binding was 7.8 in 15 mM Hepes. MgCl2, CaCl2 and spermine prevented desorption of microsomal enzyme at mu molar levels and maximal effects were observed at concentrations below the 1 mM level. At maximum, however, the prevention of desorption was less by these salts than it was by KCl. MgCl2 and spermine also interfered with the effect of KCl. Moderate salt-induced loading of microsomes with the phosphohydrolase (specific activity increased 3.5-fold) increased their ability to incorporate 14C into triacylglycerol from sn-[U-14C]glycerol 3-phosphate while a high loading (specific activity increased 6-fold) had no effect or even suppressed it. The results are discussed in relation to a role of translocation of phosphatidate phosphohydrolase in glyceride biosynthesis and its control.

Adipose Tissue↗

PubMed1981

Control of fat cell phosphohydrolase by lipolytic agents.

The Mg2+-dependent phosphatidate phosphohydrolase activity increased in the microsomal and decreased in the soluble fraction of isolated rat fat cells incubated for short periods with the lipolytic hormones or agents, epinephrine, cyclic AMP, theophylline, and dibutyryl cyclic AMP. Adrenocorticotropin, on the other hand, increased not only the microsomal but also the soluble activity. The increases in microsomal activity ranged from 30 to 134% with epinephrine to almost 200% with dibutyryl cyclic AMP. The decreases in soluble activity were more modest. The effect of epinephrine was inhibited by the beta-adrenergic antagonist propranolol while the alpha-antagonist phentolamine enhanced it. These results strongly suggest that the fat cell phosphatidate phosphohydrolase is controlled through the beta-adrenergic receptor and the activity of adenylate cyclase. Lipolysis, as measured by fatty acid release, was stimulated in a similar pattern as the microsomal activity suggesting parallel activation of the hormone sensitive lipase and phosphatidate phosphohydrolase. It is speculated that the activation of this lipogenic enzyme by lipolytic stimuli may represent a mechanism whereby fatty acid release from adipose tissue may be modulated and intracellular fatty acid accumulation may be counteracted during accelerated lipolysis in adipose tissue.

Adipose Tissue↗

PubMed1977

Soluble rat adipocyte phosphatidate phosphatase activity: characterization and effects of fasting and various lipids.

Phosphatidate phosphatase (phosphatidate phosphohydrolase, EC 3.1.3.4) was present at very high specific activity in the soluble fraction of isolated rat adipocytes. Using phosphatidate in aqueous dispersion 90% of its hydrolysis depended on the presence of Mg2+. Mg2+ appeared to almost saturate the enzyme at 20-40 mM with no indication of an optimum. The substrate concentration was optimum at 1.2 mM and the pH at 6.8. Initial rates were linear for only 4-5 min at optimum conditions. Increasing inhibition occurred at high phosphatidate concentrations. At optimum conditions acid or alkaline phosphatase activity was not measurable. The Mg2+-dependent activity was enhanced by 3-sn-phophatidylcholine and inhibited by albumin, 3-sn-phosphatidyletanolamine, 3-sn-phosphatidylinositol, diacylglycerol, oleoyl-CoA, and oleate. Oleoyl-CoA was the most potent "effector". Fasting for 24, 48 and 72 h decreased the activity both relative to protein and to DNA. The activity thus decreased to about one-third of that of the fed rat during 72 h of fasting. The effects of Mg2+, various lipids, and fasting may indicate that some form of control of glyceride synthesis can be exerted through the soluble phosphatidate phosphatase.

Adipose Tissue↗

PubMed1974