Intermuscular and perimuscular fat expansion in obesity correlates with skeletal muscle T cell and macrophage infiltration and insulin resistance.

BACKGROUND/OBJECTIVES: Limited numbers of studies demonstrated obesity-induced macrophage infiltration in skeletal muscle (SM), but dynamics of immune cell accumulation and contribution of T cells to SM insulin resistance are understudied. SUBJECTS/METHODS: T cells and macrophage markers were examined in SM of obese humans by reverse transcription-PCR (RT-PCR). Mice were fed high-fat diet (HFD) for 2-24 weeks, and time course of macrophage and T-cell accumulation was assessed by flow cytometry and quantitative RT-PCR. Extramyocellular adipose tissue (EMAT) was quantified by high-resolution micro-computed tomography (CT), and correlation to T-cell number in SM was examined. CD11a-/- mice and C57BL/6 mice were treated with CD11a-neutralizing antibody to determine the role of CD11a in T-cell accumulation in SM. To investigate the involvement of Janus kinase/signal transducer and activator of transcription (JAK/STAT), the major pathway for T helper I (TH1) cytokine interferon-γ, in SM and adipose tissue inflammation and insulin resistance, mice were treated with a JAK1/JAK2 inhibitor, baricitinib. RESULTS: Macrophage and T-cell markers were upregulated in SM of obese compared with lean humans. SM of obese mice had higher expression of inflammatory cytokines, with macrophages increasing by 2 weeks on HFD and T cells increasing by 8 weeks. The immune cells were localized in EMAT. Micro-CT revealed that EMAT expansion in obese mice correlated with T-cell infiltration and insulin resistance. Deficiency or neutralization of CD11a reduced T-cell accumulation in SM of obese mice. T cells polarized into a proinflammatory TH1 phenotype, with increased STAT1 phosphorylation in SM of obese mice. In vivo inhibition of JAK/STAT pathway with baricitinib reduced T-cell numbers and activation markers in SM and adipose tissue and improved insulin resistance in obese mice. CONCLUSIONS: Obesity-induced expansion of EMAT in SM was associated with accumulation and proinflammatory polarization of T cells, which may regulate SM metabolic functions through paracrine mechanisms. Obesity-associated SM 'adiposopathy' may thus have an important role in the development of insulin resistance and inflammation.

Bioavailability of insulin detemir and human insulin at the level of peripheral interstitial fluid in humans, assessed by open-flow microperfusion.

AIMS: To find an explanation for the lower potency of insulin detemir observed in humans compared with unmodified human insulin by investigating insulin detemir and human insulin concentrations directly at the level of peripheral insulin-sensitive tissues in humans in vivo. METHODS: Euglycaemic-hyperinsulinaemic clamp experiments were performed in healthy volunteers. Human insulin was administered i.v. at 6 pmol/kg/min and insulin detemir at 60 pmol/kg/min, achieving a comparable steady-state pharmacodynamic action. In addition, insulin detemir was doubled to 120 pmol/kg/min. Minimally invasive open-flow microperfusion (OFM) sampling methodology was combined with inulin calibration to quantify human insulin and insulin detemir in the interstitial fluid (ISF) of subcutaneous adipose and skeletal muscle tissue. RESULTS: The human insulin concentration in the ISF was ∼115 pmol/l or ∼30% of the serum concentration, whereas the insulin detemir concentration in the ISF was ∼680 pmol/l or ∼2% of the serum concentration. The molar insulin detemir interstitial concentration was five to six times higher than the human insulin interstitial concentration and metabolic clearance of insulin detemir from serum was substantially reduced compared with human insulin. CONCLUSIONS: OFM proved useful for target tissue measurements of human insulin and the analogue insulin detemir. Our tissue data confirm a highly effective retention of insulin detemir in the vascular compartment. The higher insulin detemir relative to human insulin tissue concentrations at comparable pharmacodynamics, however, indicate that the lower potency of insulin detemir in humans is attributable to a reduced effect in peripheral insulin-sensitive tissues and is consistent with the reduced in vitro receptor affinity.

Benefits and costs of improved IEQ in U.S. offices.

UNLABELLED: This study estimates some of the benefits and costs of implementing scenarios that improve indoor environmental quality (IEQ) in the stock of U.S. office buildings. The scenarios include increasing ventilation rates when they are below 10 or 15 l/s per person, adding outdoor air economizers and controls when absent, eliminating winter indoor temperatures >23°C, and reducing dampness and mold problems. The estimated benefits of the scenarios analyzed are substantial in magnitude, including increased work performance, reduced Sick Building Syndrome symptoms, reduced absence, and improved thermal comfort for millions of office workers. The combined potential annual economic benefit of a set of nonoverlapping scenarios is approximately $20 billion. While the quantitative estimates have a high uncertainty, the opportunity for substantial benefits is clear. Some IEQ improvement measures will save energy while improving health or productivity, and implementing these measures should be the highest priority. PRACTICAL IMPLICATIONS: Owners, designers, and operators of office buildings have an opportunity to improve IEQ, health, work performance, and comfort of building occupants and to obtain economic benefits by improving IEQ. These benefits can be achieved with simultaneous energy savings or with only small increases in energy costs.

Phospholipase C release of basic fibroblast growth factor from human bone marrow cultures as a biologically active complex with a phosphatidylinositol-anchored heparan sulfate proteoglycan.

Basic fibroblast growth factor (bFGF) is a potent mitogen for human bone marrow stromal cells and stimulates haematopoiesis in vitro. We report here that primary human bone marrow cultures contain bFGF and express heparin-like bFGF binding sites on the cell surface and in the extracellular matrix (ECM). bFGF bound predominantly to a 200-kD cell surface heparan sulfate proteoglycan (HSPG), which was also found in conditioned medium. bFGF was released from bone marrow cultures by incubation with phosphatidylinositol-specific phospholipase C (PI-PLC) and, less efficiently, by plasmin. Solubilized bFGF was found as a complex with the 200-kD HSPG. The complex was biologically active as shown by its ability to stimulate plasminogen activator production in bovine aortic endothelial cells. bFGF-HSPG complexes of bovine endothelial cells, however, were not released by PI-PLC. While only trace amounts of the bFGF-binding 200-kD HSPG were released spontaneously from bone marrow cultures, incubation with PI-PLC solubilized almost all of the 200-kD HSPG. The HSPG could be metabolically labeled with ethanolamine or palmitate, which was partially removed by treatment with PI-PLC. These findings indicate linkage of the HSPG to the cell surface via a phosphatidylinositol anchor. Plasmin released the 200-kD HSPG less efficiently than PI-PLC. We conclude that HSPGs of human bone marrow serve as a reservoir for bFGF, from which it can be released in a biologically active form via a dual mechanism; one involving a putative endogenous phospholipase, the other involving the proteolytic cascade of plasminogen activation.

Risk factors in heating, ventilating, and air-conditioning systems for occupant symptoms in US office buildings: the US EPA BASE study.

UNLABELLED: Building-related symptoms in office workers worldwide are common, but of uncertain etiology. One cause may be contaminants related to characteristics of heating, ventilating, and air-conditioning (HVAC) systems. We analyzed data from 97 representative air-conditioned US office buildings in the Building Assessment and Survey Evaluation (BASE) study. Using logistic regression models with generalized estimating equations, we estimated odds ratios (OR) and 95% confidence intervals for associations between building-related symptom outcomes and HVAC characteristics. Outdoor air intakes less than 60 m above ground level were associated with significant increases in most symptoms: e.g. for upper respiratory symptoms, OR for intake heights 30 to 60 m, 0 to <30 m, and below ground level were 2.7, 2.0, and 2.1. Humidification systems with poor condition/maintenance were associated with significantly increased upper respiratory symptoms, eye symptoms, fatigue/difficulty concentrating, and skin symptoms, with OR = 1.5, 1.5, 1.7, and 1.6. Less frequent cleaning of cooling coils and drain pans was associated with significantly increased eye symptoms and headache, with OR = 1.7 and 1.6. Symptoms may be due to microbial exposures from poorly maintained ventilation systems and to greater levels of vehicular pollutants at air intakes nearer the ground level. Replication and explanation of these findings is needed. PRACTICAL IMPLICATIONS: These findings support current beliefs that moisture-related HVAC components such as cooling coils and humidification systems, when poorly maintained, may be sources of contaminants that cause adverse health effects in occupants, even if we cannot yet identify or measure the causal exposures. While finding substantially elevated risks for poorly maintained humidification systems, relative to no humidification systems, the findings do not identify important (symptom) benefits from well-maintained humidification systems. Findings also provide an initial suggestion, needing corroboration, that outdoor air intakes lower than 18 stories in office buildings may be associated with substantial increases in many symptoms. If this is corroborated and linked to ground-level vehicle emissions, urban ventilation air intakes may need to be located as far above ground level as possible or to incorporate air cleaners that remove gaseous pollutants.

Chloroquine induces human macrophage killing of Histoplasma capsulatum by limiting the availability of intracellular iron and is therapeutic in a murine model of histoplasmosis.

We investigated the role of intracellular iron on the capacity of Histoplasma capsulatum (Hc) yeasts to multiply within human macrophages (Mphi). Coculture of Hc-infected Mphi with the iron chelator deferoxamine suppressed the growth of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by iron-free transferrin (apotransferrin). Chloroquine, which prevents release of iron from transferrin by raising endocytic and lysosomal pH, induced human Mphi to kill Hc. The effect of chloroquine was reversed by iron nitriloacetate, an iron compound that is soluble at neutral to alkaline pH, but not by holotransferrin, which releases iron only in an acidic environment. Chloroquine (40-120 mg/kg) given intraperitoneally for 6 d to Hc-infected C57BL/6 mice significantly reduced the growth of Hc in a dose-dependent manner. At 120 mg/kg there was a 17- and 15-fold reduction (P < 0.01) in CFU in spleens and livers, respectively. The therapeutic effect of chloroquine also correlated with the length of treatment. As little as 2 d of chloroquine therapy (120 mg/kg), when started at day 5 after infection, reduced CFU in the spleen by 50%. Treatment with chloroquine for 10 d after a lethal inoculum of Hc protected six of nine mice; all control mice were dead by day 11 (P = 0.009). This study demonstrates that: (a) iron is of critical importance to the survival and multiplication of Hc yeasts in human Mphi; (b) in vitro, chloroquine induces Mphi killing of Hc yeasts by restricting the availability of intracellular iron; and (c) in vivo, chloroquine significantly reduces the number of organisms in the spleens and livers of Hc-infected mice and can protect mice from a lethal inoculum of Hc yeasts. Thus, chloroquine may be effective in the treatment of active histoplasmosis and also may be useful in preventing relapse of histoplasmosis in patients with acquired immunodeficiency syndromes.

Isolation of surface lectins of GH3 cells from whole cells and isolated plasma membranes.

Lectins localized in the plasma membranes seem to be of special importance for the intercellular interaction mechanisms. We describe the isolation of mannose-binding proteins by Triton X-100 extraction and affinity chromatography on agarose-bound mannose. The isolation procedure was performed with whole GH3 cells as well as with isolated plasma membranes. For the isolation of plasma membranes of GH3 cells a mechanical pump was used for the disruption. After differential centrifugation an enriched plasma membrane fraction was achieved by discontinuous sucrose gradient centrifugation. The whole fractionation procedure was controlled by total balance sheets for the marker enzymes of the different cell organelles. The plasma membrane fraction was further characterized by gel electrophoresis and electron microscopy. The SDS gel electrophoresis patterns of the proteins, resulting from the Triton X-100 extraction and the affinity chromatography, are nearly identical for whole cells as well as for the enriched plasma membrane fraction. Therefore we presume these mannose-specific proteins to be plasma membrane bound, showing the molecular properties of integral proteins and having a molecular weight of Mr 67 000, 57 000, 47 000.

Changes of the internal organization of the plasma membrane correlated to the regeneration potency of the cell.

Internal organization of the plasma-membrane of rat thymocytes and pituitary tumor cells (GH3) was experimentally altered by low temperature and either changing osmolarity or adding drugs destroying the cytoskeleton. These treatments induce reversible aggregation of intramembrane particles of the plasma membrane. Thin section electron microscopy of the hypotonically shocked cells show all the cell organelles to be extremely swollen and the cytoplasmic space to be rather empty. Returned to physiological conditions, the cells show normal morphological aspects, accompanied by 'normal' permeability properties of the plasma membrane; the aggregation of intramembrane particles is reversed. The proliferation behaviour of GH3-cell is not affected by this treatment. This demonstrates a high regeneration potency of the mammalian cell and leads to the assumption that molecular components which are important for the survival of the cell must be structural (membrane) bound.

Fractionation of membrane vesicles. II. A method for separation of membrane vesicles bearing different enzymes by free-flow electrophoresis.

Free-flow electrophoresis was used to subfractionate membrane vesicles from calf thymocyte plasma membranes. The fractionation resulted in a separation of vesicle populations bearing four different enzymes: alkaline nitrophenyl-phosphatase (orthophosphoric-monoester phosphohydrolase (alkalin optimum) EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), (Mg2+ + Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) and acyl-CoA:lysophosphatidylcholine acyltransferase (acyl-CoA:1-acylglycero-3-phosphocholine-O-acyltransferase, EC 2.3.1.23). The specific content of cholesterol and total phospholipid coincided with the distribution of membrane-bound protein. However, vesicles migrating towards the cathode had a higher molar ratio of cholesterol to phospholipid (0.75) compared to those migrating to the anode (0.55). Sodium dodecyl sulphate-gel electrophoresis of pooled vesicle fractions also demonstrates distinct differences in their protein pattern. Electron-micrographic thin sections show that the vesicle populations have a similar morphology and size distribution. These results are discussed in terms of heterogeneity of the original thymocytes, contamination with intracellular membranes and a heterogeneous structure of the plasma membrane.

Plasma and interstitial glucose dynamics after intravenous glucose injection: evaluation of the single-compartment glucose distribution assumption in the minimal models.

Recent experimental evidence suggests that estimates of glucose effectiveness (S(G)) from the minimal model of unlabeled glucose disappearance (Cold-MM) are in error. The single-compartment glucose distribution assumption embedded in the model has been indicated as a possible source of error. In this study, to directly examine the single-compartment assumption, we measured plasma and interstitial glucose concentrations after intravenous glucose injection. Additionally, we compared the accuracy of the estimates of glucose effectiveness from the Cold-MM and the single-compartment tracer minimal model (Hot-MM). Paired labeled intravenous glucose tolerance tests (IVGTTs) were performed in each of six C-peptide-negative type 1 diabetic subjects. Two different insulin infusion protocols were used: an infusion at constant basal rates and an infusion at variable rates to mimic a normal insulin response. During the labeled IVGTT with basal insulin infusion, the microperfusion technique was employed to sample adipose tissue interstitial fluid. Marked differences between the plasma and interstitial dynamics of (cold) glucose were observed during the first 22 min after glucose injection. These results suggest that the requirements for a single-compartment representation of glucose kinetics are not satisfied during at least the first 22 min of an IVGTT. Data from the labeled IVGTT with normal insulin response were used to identify the minimal-model parameters. The measure of S(G) derived using the Cold-MM was 3.44-fold higher than the direct measure obtained from the labeled IVGTT with basal insulin infusion (0.0179+/-0.0027 vs. 0.0052+/-0.0010 min(-1), P<0.01). The measure of glucose effectiveness (S(G)*) derived by the Hot-MM was 1.36-fold higher than the direct measure available from the labeled IVGTT with basal insulin infusion (0.0079+/-0.0013 vs. 0.0058+/-0.0004 min(-1), P>0.26). These results suggest that the Hot-MM is more appropriate for the evaluation of glucose effectiveness than the Cold-MM.

Evaluation of a structured outpatient group education program for intensive insulin therapy.

OBJECTIVE: To determine the efficacy and safety of a structured diabetes teaching and treatment program (DTTP) in patients with insulin-dependent diabetes mellitus (IDDM) in an outpatient setting. RESEARCH DESIGN AND METHODS: All patients with IDDM who completed a structured 5-day outpatient DTTP were reevaluated after a mean follow-up of 3 years. A standardized interview was used to assess frequency of severe hypoglycemia, type of insulin treatment, self-monitoring, and other diabetes-related parameters. HbA1c was measured by high-performance liquid chromatography. RESULTS: Of 205 patients, 4 (2%) died during the observation period. HbA1c in the 201 surviving patients decreased significantly from 8.7 +/- 2.0 to 7.5 +/- 1.2% at follow-up (P < 0.001); frequency of severe hypoglycemia decreased from a mean of 0.46 to 0.13 per patient per year (P < 0.001). Hospital admission due to acute metabolic disturbances decreased from 4.5 +/- 11.1 to 1.4 +/- 6.7 days/patient-year (P < 0.001). At follow-up, intensive insulin therapy was carried out by 98% of the patients, and 80% of the patients reported three or more measurements of blood glucose per day. Diabetes-related knowledge had a positive (P < 0.01) and body mass index a negative (P < 0.02) influence on improving HbA1c assessed by multiple regression analysis. Severe hypoglycemia after DTTP was associated with a history of severe hypoglycemia before DTTP (P < 0.001) and the existence of overt diabetic nephropathy (P < 0.05). CONCLUSIONS: A structured outpatient DTTP as used in this study is able to improve overall metabolic control and decrease the frequency of severe hypoglycemia in patients with IDDM.

Accuracy of home blood glucose meters during hypoglycemia.

OBJECTIVE: To evaluate the accuracy of home blood glucose meters during hypoglycemia. METHODS: Six blood glucose meters-One Touch II (LifeScan, Milpitas, CA), Companion II (Medisense, Cambridge, U.K.), Reflolux (Boehringer Mannheim, Mannheim, Germany), Accutrend (Boehringer Mannheim), Elite (Bayer, Munich, Germany), and HemoCue (HemoCue, Angelholm, Sweden)-were compared with a reference method (Beckman Glucose Analyzer 2). Glucose concentrations from arterialized venous blood samples were measured using all glucose meters (whole blood) and the reference method (plasma) during hypoglycemic-hyperinsulinemic clamps in 15 subjects. RESULTS: In total, 663 blood glucose monitor readings and 119 reference values ranging from 2.28 to 3.89 mmol/l were analyzed. The correlation coefficients and the percentage of measurements within 20% and outside 40% of the reference values for each glucose meter were as follows: One Touch II: 0.91, 99.2% and 0%; Companion II: 0.81, 88.2% and 2.5%; Reflolux: 0.78, 85.0% and 0.9%; Accutrend: 0.88, 46.0% and 6.6%; Elite: 0.78, 75.6% and 4.2%; and HemoCue: 0.93, 96.6% and 0% (P < 0.001). CONCLUSIONS: There were substantial differences between the blood glucose meters during hypoglycemia, and none of the devices met the latest criteria recommended by the American Diabetes Association.

Open-flow microperfusion of subcutaneous adipose tissue for on-line continuous ex vivo measurement of glucose concentration.

OBJECTIVE: To evaluate a novel technique for on-line continuous glucose measurement in subcutaneous adipose tissue, and to investigate its accuracy for detection of hypoglycemia. RESEARCH DESIGN AND METHODS: The method combined an open-flow microperfusion of subcutaneous adipose tissue using a double lumen catheter and an extracorporeal sensor cell. An isotonic ion-free solution was perfused through the inner lumen of the catheter, equilibrated with the subcutaneous tissue fluid, and sampled through the outer lumen. The recovery was continuously monitored as the ratio between the measured sampled fluid conductivity and the subcutaneous tissue fluid conductivity (assumed to have a constant value of 1.28 S/m at 25 degrees C). Glucose concentration was calculated on-line from the measured glucose in the sampled fluid and the measured recovery in healthy volunteers during hyperglycemic glucose loads (n = 8), hypoglycemic hyperinsulinemic clamp (n = 6), and a 24-h monitoring period (n = 7). RESULTS: Subcutaneous glucose concentrations in the fasting state were 94% of the plasma glucose concentrations in arterialized venous samples. According to the error grid analysis, 96.9% of the on-line measured subcutaneous glucose concentrations during hyperglycemia and 96.3% during hypoglycemia were in accurate or acceptable zones. The mean differences between the measured subcutaneous glucose and the actual plasma glucose concentration were -0.06-3.3 mmol/l (hyperglycemia), and -0.6-1.1 mmol/l (hypoglycemia). CONCLUSIONS: By combining open-flow microperfusion, glucose sensor, and conductivity measurement, glucose concentration in the subcutaneous adipose tissue can be monitored on-line, extracorporeally, and continuously without any in vivo calibration, and gives accurate measurements during hyper- and hypoglycemia.

Validation of home blood glucose meters with respect to clinical and analytical approaches.

OBJECTIVE: To evaluate the clinical and analytical accuracy of home blood glucose meters. RESEARCH DESIGN AND METHODS: Six blood glucose meters--Reflolux S (Boehringer Mannheim, Mannheim, Germany), One Touch II (LifeScan, Milpitas, CA), Glucocard Memory (Menarini, Florence, Italy), Precision QID (Medisense, Cambridge, U.K.), HaemoCue (HaemoCue, Angelholm, Sweden), and Accutrend alpha (Boehringer Mannheim, Mannheim, Germany)--were compared with a reference method (Beckman Glucose Analyzer II) under controlled conditions (glucose clamp technique). Validation of the blood glucose meters was accomplished by clinically oriented approaches (error grid analysis), statistical approaches (variance components analysis), and by the criteria of the American Diabetes Association (ADA), which recommend a target variability of < 5%. RESULTS: A total of 1,794 blood glucose monitor readings and 299 reference values ranging from 2.2 to 18.2 mmol/l were analyzed (705 readings < 3.89 mmol/l, 839 readings between 3.89 and 9.99 mmol/l, and 250 readings > 9.99 mmol/l). According to error grid analysis, only Reflolux S and Glucocard M had 100% of estimations within the clinically acceptable zones A and B. Assessment of analytical accuracy revealed substantial differences between the glucose meters after separation of the data into defined glycemic ranges. None of the devices met the ADA criteria. CONCLUSIONS: To evaluate accuracy of blood glucose meters, error grid analysis, as well as statistical models, are helpful means and should be performed together. Analytical performance of currently available home blood glucose meters differs substantially within defined glycemic ranges.

Lactate metabolism of subcutaneous adipose tissue studied by open flow microperfusion.

Open flow microperfusion and a novel calibration technique (ionic reference technique) were evaluated for the frequent measurement of the absolute lactate concentration in sc adipose tissue. Furthermore, the influence of the plasma insulin concentration on the lactate concentration of sc adipose tissue was investigated during hyperglycemia. Sixteen lean healthy young men participated in the studies. In the postabsorbtive state the mean sc lactate concentrations were 1.29 and 1.36 mmol/L for the ionic reference technique and the no net flux protocol, respectively (not significant, P > 0.05). The simultaneously measured arterialized plasma lactate concentration was significantly lower at 0.77 mmol/L (P < 0.05). Both the sc lactate concentration (1.8+/-0.33 mmol/L) and the plasma lactate concentration (0.96+/-0.03 mmol/L) were significantly elevated during a hyperinsulinemic euglycemic clamp experiment. During a hyperglycemic clamp experiment the sc lactate concentration reached a significantly elevated plateau (2.15+/-0.27 mmol/L) that was not influenced by the increasing plasma insulin concentration. It is concluded that 1) open flow microperfusion combined with the ionic reference technique enables frequent measurement of the sc lactate concentration; 2) sc adipose tissue is a significant source of lactate release in the postabsorbtive state as well as during hyperinsulinemic clamp conditions; and 3) insulin concentrations greater than 180 pmol/L have no further influence on adipocyte stimulation of sc adipose tissue with respect to lactate release.

Activation of pro-urokinase by the human T cell-associated serine proteinase HuTSP-1.

The human T cell-associated serine proteinase-1 (HuTSP-1) is expressed by activated T lymphocytes and is exocytosed upon their interaction with target cells. Here, we report that HuTSP-1 is able to convert single-chain human pro-urokinase into the active two-chain enzyme. Time-dependent activation by HuTSP-1 of recombinant human pro-urokinase as well as natural pro-urokinase derived from human melanoma cells was demonstrated in a chromogenic assay specific for active urokinase type plasminogen activator and in immunoblotting experiments revealing the conversion of single-chain into two-chain urokinase. Control experiments excluded plasmin as the activating agent. These data suggest a novel pathway for plasmin generation during T cell-mediated processes such as immune responses and extravasation of immune cells.

Tryptophan requirement in young adult women as determined by indicator amino acid oxidation with L-[13C]phenylalanine.

To determine tryptophan requirements with use of the indicator amino acid oxidation technique, we studied 5 healthy, premenopausal women who each consumed 6 different intakes of tryptophan. The energy-sufficient diet contained 1.0 g x kg(-1) x d(-1) of an L-amino acid mixture patterned after egg protein, with adequate phenylalanine (14 mg x kg(-1) x d(-1)) and excess tyrosine (40 mg x kg(-1) x d(-1)). The effect of graded alterations in dietary tryptophan on phenylalanine flux and oxidation was studied by using L-[1-(13)C]phenylalanine as the indicator amino acid. Graded increases in tryptophan had no effect on phenylalanine flux. Determined by two-phase linear regression crossover analysis, the mean tryptophan requirement based on indicator (phenylalanine) oxidation was 4.01 mg x kg(-1) x d(-1), with a safe intake at 5.02 mg x kg(-1) x d(-1). These results show that the indicator amino acid oxidation technique can be used to determine the requirement for amino acids such as tryptophan that cannot be successfully studied by direct oxidation because of their characteristic metabolism. Our value of safe intake for 95% of the population was found to be 43% higher than that reported previously for adults.

Roxatidine acetate in the long term maintenance of duodenal ulcers.

A non-comparative multicentre study of 105 patients with healed duodenal ulcers was conducted to determine the effect on ulcer recurrence of 6 months' maintenance treatment with roxatidine acetate 75 mg daily. All patients had previously received roxatidine acetate treatment. 31 patients out of 89 had 32 relapsed ulcers after 6 months of treatment, which represents an overall relapse rate of around 30%; the relapse rate in smokers was double that of non-smokers. The overall incidence of epigastric pain did not increase significantly over the period of the trial, although some patients complained of mild pain when they entered the study despite having endoscopically confirmed healed ulcers. At the end of the study continuous poor appetite and pyrosis were reported by 17% and 6% of patients, respectively. Side effects, which included constipation and diarrhoea, were reported by 4 patients, 1 of whom withdrew from therapy. There were no clinically significant changes in laboratory values. Thus, maintenance treatment with roxatidine acetate 75 mg daily proved a safe and effective method of preventing symptomatic duodenal ulcer relapse.

Adhesive function of newcastle-disease virus hemagglutinin in tumor-host interaction.

Infection of metastatic lymphoma cells (ESbL) by a low dose of a non-lytic strain of Newcastle disease virus (NDV) leads to viral replication followed by strong cell surface expression of viral antigens, especially hemagglutinin neuraminidase (HN). The expressed HN was functional and facilitated cell-cell interactions and cell attachment. This was shown for NDV infected tumor cells, lymphocytes, fibroblasts and endothelial cells. The interactions could be strongly inhibited by antibodies against the viral HN protein. Increased binding was also seen with HN c-DNA transfectants expressing the HN as the only viral protein. Viral infection did not influence proliferation and lysability of the infected tumor cells. Following intravenous injection of tumor cells, the number of hepatic metastases was significantly reduced when the cells had been pre-infected with NDV. This reduction of metastases correlated with an increased survival time of the animals. As potential mechanisms of these NDV effects we propose augmentation of cell-eel interactions and immune functions and reduction of invasive capacity of NDV infected, as compared to non-infected tumor cells.

Long-term therapy with pantoprazole in patients with peptic ulceration resistant to extended high-dose ranitidine treatment.

Patients (106) with peptic ulceration of the oesophagus, stomach and duodenum, unresponsive to 3 or more months of high-dose treatment with ranitidine, were initially given pantoprazole (40-80 mg, p.o.) daily. In 96.7% of the patients ulcers healed within 2 to 8 weeks, and in 2.3% of patients the ulcers healed within 12 weeks. In just one patient with severe oesophagitis, the lesion took more than 6 months to heal. After ulcer healing, patients (98 to date) were treated with pantoprazole (40 mg/day) as long-term maintenance therapy. Eighty-eight of the 98 patients have been taking pantoprazole for 6 months to 3 years. During maintenance therapy, peptic disease was kept in remission in most patients with 40 mg pantoprazole. Twelve patients with oesophagitis and two patients with gastric ulcers needed higher doses (80-120 mg) to control the disease. One female patient developed peripheral oedema which disappeared quickly after stopping treatment. No further drug-related adverse effects were observed. Seven patients withdrew from the study and two patients died, all for non-drug-related reasons. Routine laboratory tests remained without significant changes in all patients. Mean (+/- S.E.M.) serum gastrin levels were already elevated during the initial high-dose ranitidine treatment (128 +/- 23 pg/ml). Within one year of the start of the pantoprazole treatment, serum gastrin levels rose to 3 times normal values (189 +/- 32 pg/ml). Thereafter, no further increases in serum gastrin were observed for up to 2.5 years. Enterochromaffin-like (ECL) cell density increased very slightly from 0.19% to 0.24% within one year.(ABSTRACT TRUNCATED AT 250 WORDS)