Changes in catecholamine-induced lipolysis in isolated human fat cells during the first year of life.

Catecholamine-induced lipolysis in isolated human adipocytes during the first year of life was investigated. During this period fat cell size increased markedly. Basal and catecholamine-induced glycerol release were positively correlated with age when lipolysis was expressed per cell. However, when lipolysis was expressed per unit of cell surface area (micrometer squared), this correlation was observed only for noradrenaline. Basal lipolysis and the effect of the pure beta-agonist, isoprenaline, were identical in infants and adults. From 0 to 2 mo of age noradrenaline had very little lipolytic effect. The addition of the alpha-2-adrenoceptor antagonist, yohimbine, to noradrenaline equalized lipolysis per micrometer squared in infants and adults and the alpha-2-adrenoceptor sensitivity was significantly enhanced in infants. In both groups the lipolytic adrenoceptor was of the beta-1 type. In conclusion, adipocytes from infants have a poor lipolytic response to noradrenaline partly because of the small fat cells but mainly because of an enhanced alpha-2-adrenoceptor activity.

Mechanisms for differences in lipolysis between human subcutaneous and omental fat cells.

Catecholamine-regulation of lipolysis and beta-adrenoceptor binding isoterms were studied in human sc and omental isolated fat cells from 24 subjects undergoing elective cholecystectomy. The lipolytic sensitivity of the nonselective beta-agonists epinephrine and isoprenaline as well as the selective agonists norepinephrine (beta 1) and terbutaline (beta 2) was significantly increased 5-10 times in omental fat cells. On the other hand, no regional difference in antilipolytic sensitivity was seen for the alpha 2 agonist clonidine. No regional difference in lipolytic action was seen when measuring the effect of forskolin, (Bu)2cAMP or enprofylline, which act at different postadrenoceptor steps in the lipolytic cascade. Lipolysis data showed no sex differences. A beta 1-pattern was seen in both regions when lipolysis dose-response curves were arranged in order of potency. Radioligand saturation experiments with the nonselective beta-antagonist 125I-cyanopindolol and competition experiments between this radioligand and the selective antagonists CGP-20,712-A (beta 1) and ICI-118551 (beta 2) showed a 2-fold increase in the amount of beta 1- and beta 2-adrenergic receptors in omental as compared to sc fat cells (P less than 0.02). Competition studies with the same radioligand and the nonselective beta-agonist isoprenaline showed no regional differences in terms of receptor affinity (Kd high 10 nM and Kd low 1 microM) or in relative fraction of receptors in the high affinity state (35%). It is concluded that an increased lipolytic sensitivity for beta 1- and beta 2-agonists can be due to an increase in the amount of the two adrenoceptor subtypes in omental fat cells and thereby explain why catecholamines are more lipolytic in omental cells than in sc fat cells.

Beta-adrenoreceptor subtype expression in human liver.

The pharmacological and gene expressions of beta 1- and beta 2-adrenoceptor subtypes (BAR1 and BAR2) were investigated in human liver by radioligand binding assays, adenylate cyclase experiments, and RNA excess solution hybridization. [125I]Cyanopinodolol, nonlabeled adrenergic agents, and BAR1/BAR2 cRNA were used as probes. The relationship between binding sites for BAR1 and BAR2 was markedly different from that between the basal mRNA expression for the two receptor subtypes. Plasma membranes as well as a microsomel-enriched fraction contained binding sites only for BAR2. The potency of BAR agonists and antagonists in stimulating adenylate cyclase activity of plasma membranes was typical of a BAR2 response. Northern blot analysis of total cellular RNA isolated from liver tissue showed hybridization of the BAR1 probe to a mRNA species of 2.5-2.6 kilobases and of the BAR2 probe to a mRNA species of 2.2-2.3 kilobases. The basal level of BAR1 mRNA was 5-fold higher than of BAR2 mRNA, as assayed by solution hybridization. No difference in BAR subtype mRNA stability was observed, as indicated by a mRNA half-life of approximately 5.5 h for both receptor subtypes. It is concluded that specific factors are involved in the steady state regulation of BAR subtype expression in human liver. This tissue contains solely BAR2 owing to a posttranscriptional block of basal BAR1 expression.

Different dose regimens of 5-fluorouracil and interferon-alpha in patients with metastatic colorectal carcinoma.

Three different 5-fluorouracil (5-FU)-interferon-alpha-2b (IFN)-containing regimens were designed for treatment of patients with advanced colorectal cancer. 87 patients with a Karnofsky index > or = 70 were included in three sequential non-randomised phase II trials. Regimen A consisted of 5-FU (750 mg/m2/day) given as a continuous infusion on days 1-5 followed by weekly 1-h intravenous infusions until week 8. IFN (5 MU) was given subcutaneously on days 1, 3 and 5 followed by injections (9 MU) every second day until week 8. The cycle was then repeated. Regimen B consisted of 5-FU (750 mg/m2/day) given as a continuous infusion on days 1-5 followed by 5-min intravenous injections on days 12 and 19. IFN (3 MU) was given subcutaneously on days 1-5 followed by injections (5 MU) on days 11-13 and 18-20. The cycle was repeated every fourth week. Regimen C consisted of 5-FU (750 mg/m2/day) given as a continuous infusion on days 1-5. IFN (3 MU) was given subcutaneously on days 1-5. The cycle was repeated every third week. The objective response rates (complete response (CR) and partial response (PR)) after approximately 4 months of therapy or longer were as follows: regimen A (n = 27) 22% (2 CR, 4 PR), regimen B (n = 33) 42% (4 CR, 10 PR) and regimen C (n = 27) 22% (1 CR, 5 PR). The corresponding response figures for previously untreated patients were regimen A 50%, regimen B 64% and regimen C 38%. Response durations varied from a few weeks up to 142 + weeks. Toxicities were generally mild and reversible, and the treatments were convenient for the patients and cost effective since the 5-day infusions could be given by a portable pump without hospitalisation. Our results are in agreement with those of others showing that 5-FU/IFN combinations can be highly effective in advanced colorectal cancer, and that a number of factors such as doses, dose intensities, infusion rates and timing of the two drugs may be crucial for the anti-tumour activity of this drug combination.

Quantitative comparison of insulin-like growth factor mRNA levels in human and rat tissues analysed by a solution hybridization assay.

In this study a solution hybridization assay was evaluated for its application to the measurement of levels of specific mRNAs. The evaluation included parameters such as incubation time, hybridization stringency and probe concentration/structure. Both short (50 bases derived from synthetic oligonucleotides) and long (125-147 bases) RNA probes, derived from cloned sequences, could be used to obtain quantitative information on specific mRNA species. The solution hybridization assay was used to compare the levels of insulin-like growth factor-I (IGF-I) and IGF-II mRNAs in various rat and human tissues. In the rat the liver was the main source of IGF-I mRNA (approximately 400 molecules/cell), but significant levels were also found in extrahepatic tissues such as fat and muscle (3-50 molecules/cell). Human liver contained approximately 100-fold less IGF-I mRNA than rat liver. Human fat, muscle and placenta contained levels of IGF-I mRNA (2-8 molecules/cell) similar to those in the liver. Levels of IGF-II mRNA in rat and human tissues were similar, in that the expression was greatest in the placenta (approximately 200 molecules/cell). Species differences were evident, however, since human liver and fat contained significant amounts of IGF-II mRNA (15-20 molecules/cell), while the rat counterparts had almost undetectable levels. Young and old rats were used to examine the influence of age on the expression of IGF-I and GH receptor mRNAs in the liver. Levels of both IGF-I mRNA and GH receptor mRNA were found to decrease with age (2.8-fold and 1.7-fold respectively). It is concluded that low levels of IGF mRNAs can be detected using the solution hybridization assay and that there are considerable species differences within and between tissues with regard to steady-state levels of IGF-I and IGF-II mRNAs.

Inhibition by nicotine of the formation of prostacyclin-like activity in rabbit and human vascular tissue.

1 Rings of vascular tissue (from rabbit aorta or human peripheral vein) were incubated at room temperature in Tyrode solution in the absence or presence of nicotine or indomethacin. 2 Addition of portions of the incubates to human platelet-rich plasma (HPRP) elicited a decrease in adenosine 5'-diphosphate (ADP)-induced platelet aggregation in this plasma. Authentic prostacyclin (PGI2) also induced such a decrease. The decreased aggregation amplitudes that followed the addition of the vascular tissue incubates and of PGI2 were equally potentiated by theophylline (10(-4) M). 3 Both nicotine and indomethacin counteracted the formation of platelet anti-aggregatory activity in the vascular tissue incubates. The IC50S of nicotine and of indomethacin on the formation of platelet antiaggregatory activity were 2 X 10(-5) M and 6 X 10(-6) M, respectively. 4 Nicotine failed to affect the platelet anti-aggregatory effect induced by authentic PGI2 in HPRP. 5 It is concluded that nicotine counteracts the formation of platelet anti-aggregatory activity in rabbit aorta and human peripheral vein by eliciting an inhibitory effect on the bioformation of prostacyclin in these types of vascular tissue.

Glucocorticoid receptor mRNA expression in pulmonary alveolar macrophages in sarcoidosis.

The presence of the glucocorticoid receptor was demonstrated by immunocytochemistry in pulmonary alveolar macrophages obtained by bronchoalveolar lavage. Also, GR mRNA content was determined by solution hybridization in PAM from 12 healthy volunteers and in 6 patients with sarcoidosis. No significant differences with regard to GR mRNA expression was detected between the two groups examined. For comparison, lung tissue from three patients undergoing thoracic surgery was examined and found to contain GR mRNA levels in the same range. As an indication of GR function, we also determined the mRNA levels of a glucocorticoid-regulated gene, metallothionein IIA, during basal conditions and after in vitro incubation of PAM with dexamethasone. Neither the control sample nor the dexamethasone-stimulated MTII mRNA values in PAMs differed significantly between the two groups. Solution hybridization is a rapid, sensitive and convenient assay which enables accurate and specific quantitation of GR mRNA in PAM. The GR mRNA content and basal as well as dexamethasone-induced MTII mRNA levels in PAM from patients with sarcoidosis is not significantly different from those in healthy volunteers.

Ontogeny of a human polychlorinated biphenyl-binding protein. Level of expression in tracheal aspirates in bronchopulmonary dysplasia.

A human lung polychlorinated biphenyl binding protein (PCB-BP,M(r) 13 kd) has recently been purified from lavage fluid. Polyclonal monospecific antibodies against PCB-BP were produced and used for immunohistochemical staining in sections of human lung tissue. PCB-BP was found to localize preferentially to the nonciliated (Clara) cells of the lung, whereas the alveolar cells and ciliated cells of the larger airways were devoid of staining. Tracheal aspirates from infants receiving mechanical ventilation were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis separation and Western immunoblotting. The antibodies to human PCB-BP detected a single band of the expected molecular weight, and a quantitative analysis of the ontogeny of PCB-BP in tracheal aspirates was performed by construction of Western immunoblot standard curves. A significant increase in the levels of PCB-BP in late gestation (gestational weeks 39 to 41) was demonstrated. In similar experiments, levels of PCB-BP in tracheal aspirates obtained from infants with bronchopulmonary dysplasia (BPD) at the postconceptional age of less than 38 weeks were found to be significantly elevated as compared with a normal study group of similar gestational age (21.8 +/- 4.8 vs 3.1 +/- 0.8 ng of PCB-BP per microgram of total protein, p < 0.005). It is suggested that the high levels of PCB-BP at the postconceptional age of less than 38 weeks observed in infants with BPD may reflect inflammatory injury and regeneration of airway epithelium, associated with proliferation of Clara cells.

Ileofemoral thromboendarterectomy through retroperitoneal approach.

Seven years' experience with retroperitoneal thromboendarterectomy for ileofemoral obstruction has been reviewed. Eighty-five limbs in 75 patients were operated upon. Thirty-four limbs received simultaneous femoropopliteal bypass graft. Operative mortality (3.5%) and morbidity rates were low. The average postoperative hospital stay was 11 days. Only four ileofemoral segments thrombosed for cumulative 1-month and 5-year patency rates of 98.8% and 93.8%, respectively. In addition two femoropopliteal grafts became occluded, leaving, however, the proximal reconstructions patent. The safety, effectiveness, and smooth postoperative course of this operation in both good risk and poor risk patients suggest that it is a most satisfactory alternative to other reconstructive procedures. It is well suited for the treatment of both unilateral and-as a staged operation-bilateral ileofemoral occlusions, and it can ideally be combined with a femoropopliteal bypass. Advantages compared to conventional transabdominal operations and extra-anatomic bypass grafts are discussed.

Characterization of insulin resistance after surgery.

The effects of insulin on glucose utilization were investigated in seven nonobese patients before and 24 hours after elective cholecystectomy. Surgery was followed by a significant increase in the circulating levels of glucose and insulin. The hypoglycemic action of insulin was reduced by one third (p less than 0.01) after surgery. In isolated fat cells after surgery there was a significant overall reduction of 35% to 50% of the effects of insulin on 3-0-methylglucose transport and lipogenesis at 1 mumol/L of glucose (where hexose transport is rate-limiting for insulin action). However, there was no change in insulin sensitivity in these cells. The effects of insulin on lipogenesis in adipocytes incubated with 100 mumol/L of glucose (where glucose metabolism is rate-limiting for insulin action) and adipocyte insulin receptor binding were not influenced by surgery. Insulin action in vivo and in vitro was not altered in five nonoperated control subjects 24 hours after they were given the same type of nutritional support as the cholecystectomy patients postoperatively. It was concluded that an elective moderate surgical trauma induces a rapid and marked insulin resistance that is not the result of postoperative nutritional restriction and involves a postreceptor binding alteration of glucose transport.

Circulatory effects of VIP in anesthetized man.

VIP was given intravenously over 1 min at the doses 0.1 and 0.2 micrograms X kg X min-1 to twenty-one anesthetized patients undergoing abdominal surgery. Intra-arterial blood pressure was monitored and various blood flows were measured simultaneously by electromagnetic technique. Following VIP, intra-arterial blood pressure was decreased. The blood flows were increased in the gastroduodenal-, and the left gastric arteries. The flow in the hepatic artery proper was increased only following the 0.2 micrograms dose. The flow in the superior mesenteric artery varied considerably inter-individually. In branches supplying only the small intestine, it seemed to be unaffected. The flow in the splenic artery was decreased in normal-sized spleens, but unaffected in enlarged spleens. The flow in the external iliac artery initially decreased and thereafter increased. Changes in vascular resistances showed that VIP acted as a vasodilator in the splanchnic region except in the superior mesenteric vasculature, where it was ineffective. In normal spleens it was a vasoconstrictor. In the external iliac artery, an initial insignificant vasoconstriction was followed by vasodilation. It seemed that VIP acts directly on the vessels and has a specific pattern of vasoactivity of probable physiological significance.

Reconstructive vascular surgery for intermittent claudication.

Over an 8-year period, 140 patients underwent 172 vascular reconstructions (187 reconstructed limbs) to relieve disabling intermittent claudication: bilateral aortoiliac or aortoileofemoral thrombendarterectomy (30 limbs), unilateral iliac or ileofemoral thrombendarterectomy (41 limbs), simultaneous unilateral ileofemoral thrombendarterectomy and femoropopliteal saphenous vein bypass graft (23 limbs), femoropopliteal saphenous vein bypass graft alone (93 limbs). The cumulative 5-year limb patency rates varied between 100 and 85.6% in the four groups. Age and diabetes did not influence patency rates. Only 2 limbs required amputation. These results indicate that reconstruction can be undertaken with a high rate of long-term patency and symptomatic relief In patients with restricting claudication due to aortoiliac, ileofemoral and/or femoropopliteal occlusion.

Factors determining outcome of reversed saphenous vein femoropopliteal bypass grafts.

The investigation was designed to study factors that might be of predictive value in femoropopliteal vein bypass grafting. A series of 146 grafts had a cumulative 5-year graft patency of 82.5 per cent. Five-year limb survival rate in salvage cases was 77.9 per cent. These results are encouraging. However, taking certain factors into account, the patency rates varied. In limbs with claudication, the 5-year graft patency rate was significantly higher than in salvage procedures (P < 0.05). Basal and maximal (during pharmacological vasodilatation) intraoperative graft flow rates were also significantly higher in claudicating limbs (P < 0.01). Reconstructions in limbs with a good run-off had better patency and flow rates than in limbs with a poor run-off (P < 0.001). This suggests that progression of distal atherosclerosis is a major factor for late graft thrombosis. The incidence of graft thrombosis was correlated with the flow rates (P < 0.01). Age, the presence of diabetes, graft diameter and the site of the distal anastomosis did not affect patency.

Pharmacological vasodilation during reconstructive vascular surgery.

The effect on graft blood flow of two vasodilatory drugs, papaverine and bamethane (Vasculat), was infestigated by electromagnetic flowmetry intra-operatively in 31 patients following vascular reconstruction with a femoro-popliteal reversed saphenous vein bypass graft. With both drugs, graft flow augmentation was dose dependent (p less than 0.01) with increasing flow rates up to the injection into the popliteal artery of 40 mg of papaverine and 100 mg of bamethane respectively. The increase in graft flow rate was significantly more pronounced during vasodilation with 40 mg of papaverine than when 100 mg of bamethane was injected (p less than 0.001). Furthermore, 40 mg of papaverine and 100 mg of bamethane respectively induced a significantly larger increase in graft blood flow when injected into the popliteal artery than into the common femoral artery (p less than 0.01). The interpretation of these findings is discussed, and the augmented graft flow values presented are compared to those previously reported. From the present results, it is recommended that, for 'maximal' intra-operative flow augmentation, papaverine should be used, the dose being 40 mg injected into the popliteal artery or into the graft, but not into the common femoral artery or elsewhere intra-arterially.