Brown adipose tissue is involved in diet-induced thermogenesis and whole-body fat utilization in healthy humans.

BACKGROUND/OBJECTIVES: Brown adipose tissue (BAT) is a potential therapeutic target against obesity and diabetes through thermogenesis and substrate disposal with cold exposure. The role of BAT in energy metabolism under thermoneutral conditions, however, remains controversial. We assessed the contribution of BAT to energy expenditure (EE), particularly diet-induced thermogenesis (DIT), and substrate utilization in human adults. METHODS: In this cross-sectional study, BAT activity was evaluated in 21 men using 18F-fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography (18F-FDG-PET/CT) after cold exposure (19 °C). The subjects were divided into BAT-positive (n=13) and BAT-negative (n=8) groups according to the 18F-FDG-PET/CT findings. Twenty-four hour EE, DIT and respiratory quotient were measured using a whole-room indirect calorimeter at 27 °C. RESULTS: Body composition, blood metabolites and 24-h EE did not differ between groups. DIT (%), calculated as DIT divided by total energy intake, however, was significantly higher in the BAT-positive group (BAT-positive: 9.7±2.5%, BAT-negative: 6.5±4.0%, P=0.03). The 24-h respiratory quotient was significantly lower (P=0.03) in the BAT-positive group (0.861±0.027) than in the BAT-negative group (0.889±0.024). CONCLUSION: DIT and fat utilization were higher in BAT-positive subjects compared to BAT-negative subjects, suggesting that BAT has a physiologic role in energy metabolism.

(NZW x BXSB)F1 mouse. A new animal model of idiopathic thrombocytopenic purpura.

A decrease in thrombocyte count was observed in (NZW x BXSB)F1 (W/B F1) mice at the age of greater than 5 mo, whereas megakaryocyte counts were found to increase in such mice. FACS analyses revealed the presence of both platelet-associated antibodies (PAA) and circulating antiplatelet antibodies. There is a correlation between the presence of these antibodies and the degree of thrombocytopenia. The transplantation of normal bone marrow cells from BALB/c nu/nu mice to W/B F1 mice was found to have preventative and curative effects on thrombocytopenia; the mice showed normal platelet counts and no evidence of circulating antiplatelet antibodies. These results indicate that thrombocytopenia in W/B F1 mice is due to the presence of antibodies to platelets. We therefore think that W/B F1 mice serve as a useful animal model of idiopathic thrombocytopenic purpura (ITP) not only for elucidating the mechanism of the development of antiplatelet antibodies, but also for characterizing autoantibodies to platelets.

A multiple shock tube and chemical kinetic modeling study of diethyl ether pyrolysis and oxidation.

The pyrolysis and oxidation of diethyl ether (DEE) has been studied at pressures from 1 to 4 atm and temperatures of 900-1900 K behind reflected shock waves. A variety of spectroscopic diagnostics have been used, including time-resolved infrared absorption at 3.39 mum and time-resolved ultraviolet emission at 431 nm and absorption at 306.7 nm. In addition, a single-pulse shock tube was used to measure reactant, intermediate, and product species profiles by GC samplings at different reaction times varying from 1.2 to 1.8 ms. A detailed chemical kinetic model comprising 751 reactions involving 148 species was assembled and tested against the experiments with generally good agreement. In the early stages of reaction the unimolecular decomposition and hydrogen atom abstraction of DEE and the decomposition of the ethoxy radical have the largest influence. In separate experiments at 1.9 atm and 1340 K, it is shown that DEE inhibits the reactivity of an equimolar mixture of hydrogen and oxygen (1% of each).

Greater fat oxidation with diacylglycerol oil consumption for 14 days compared with triacylglycerol oil consumption in overweight men and women.

BACKGROUND: Several studies have reported increased fat oxidation with diacylglycerol (DAG) oil consumption. However, the effects of long-term DAG oil consumption on energy metabolism remain to be investigated. OBJECTIVE: The objective of this study was to compare the effects of 14 days of either DAG or triacylglycerol (TAG) oil consumption on substrate oxidation, energy expenditure (EE) and dietary fat oxidation. DESIGN: Eight males and six females participated in this randomized, double-blind, crossover feeding study. Each patient consumed the 14-day controlled test diet containing either 10 g day(-1) of DAG or TAG oil for acclimatization before a respiratory chamber measurement, followed by a 2-week washout period between diet treatments. Substrate oxidation and EE were measured in the respiratory chamber at the end of each dietary treatment. The patients consumed test oil as 15% of total caloric intake in the respiratory chamber (mean test oil intake was 36.1+/-6.6 g day(-1)). RESULTS: Twenty-four hour fat oxidation was significantly greater with 14 days of DAG oil consumption compared with TAG oil consumption (78.6+/-19.6 and 72.6+/-14.9 g day(-1), respectively, P<0.05). There were no differences in body weight or body composition between diet treatments. Dietary fat oxidation was determined using the recovery rate of (13)CO(2) in breath, and was significantly enhanced with DAG oil consumption compared with TAG oil consumption, measured over 22 h after ingestion of (13)C-labelled triolein. Resting metabolic rate (RMR) was significantly greater with DAG oil consumption compared with TAG oil consumption (1766+/-337 and 1680+/-316 kcal day(-1), respectively, P<0.05). CONCLUSION: Consumption of DAG oil for 14 days stimulates both fat oxidation and RMR compared with TAG oil consumption, which may explain the greater loss of body weight and body fat with DAG oil consumption that has been observed in weight-loss studies.

CT pulmonary angiogram with 60% dose reduction: Influence of iterative reconstructions on image quality.

GOALS: To compare the quality of low-dose CT images with sinogram affirmed iterative reconstruction (SAFIRE), and full-dose CT with filtered back projection reconstructions (FBP). MATERIALS AND METHODS: Fifty pulmonary CT performed by a dual-source technique (120kVp; 110mAs) with (a) the same energy in both tubes, and (b) the distribution of reference mAs with 40% in tube A (44mAs) and 60% in tube B (66mAs). Each acquisition allowed reconstruction of: (a) full-dose images (with both tubes) with FBP reconstructions (group 1); and (b) low-dose images (from tube A) reconstructed with SAFIRE (group 2). RESULTS: Group 2 images presented: (a) a significant objective reduction in noise measured in the trachea on mediastinal (16.04±5.66 vs 17.66±5.84) (P=0.0284) and pulmonary (29.77±6.79 vs 37.96±9.03) (P<0.0001) images; (b) a similar subjective perception of noise and overall image quality (P=1), which was considered to be excellent in 66% (33/50) of the cases, with no influence on the detection of elementary pulmonary lesions of infiltration (98.4%; 95% CI=[96.9%-99.9%]). CONCLUSION: Despite a 60% reduction in radiation dose, the image quality with iterative reconstruction is objectively better and subjectively similar to full-dose FBP images.

Effect of the sugar chain of soluble recombinant CD59 on complement inhibitory activity.

A soluble recombinant CD59#77 (rCD59#77), consisting of 77 amino acids starting from the N terminus of membrane-bound CD59, was prepared using a gene expression system in CHO cells. The rCD59#77 preparation was composed of glycosylated and non-glycosylated forms (G and NG forms). Unexpectedly, NG form was 7 times more potent than G form in complement inhibitory activity. Postulating that sialic acids on G-form molecules make it difficult for rCD59#77 to access nascent membrane attack complexes on the cell surface, the sialic acids were removed by neuraminidase treatment. However, the inhibitory activity was not changed. Next, one of two putative N-glycosylation sites was mutated by substituting Gln18 for Asn18. The mutant, designated rCD59#77(N/Q), had no sugar moiety and was as active as the NG form of rCD59#77. These results suggest that the bulky sugar moiety at Asn18 is not necessary for the complement-inhibitory activity of rCD59 and actually hampers that function.

Localization of vagal cardioinhibitory preganglionic neurons with rat brain stem.

In chloralose-urethane anesthetized spinal rats, electrical stimulation of systematically chosen points over the entire caudal brain stem area was carried out to explore the site(s) responsible for vagally mediated bradycardia. A dorsomedial locus including the nucleus dorsalis and the adjacent structures, the nucleus tractus solitarius, the nucleus commissuralis and the area postrema, and a ventrolateral locus around the nucleus ambiguus were found to elicit bradycardia with low threshold and high responsiveness. In another series of experiments, horseradish peroxidase (HRP) was iontophoretically administered through a glass capillary microelectrode into the identified cardiac branch of the vagus nerve of rats in order to localize more precisely the cells of origin of vagal cardioinhibitory fibers within the brain stem. Distribution of the HRP-labeled cells was not confined to one area, but these cells were found within the nucleus dorsalis, the reticular formation surrounding the nucleus ambiguus and an intermediary zone between the two nuclei. Such a pattern of distribution of vagal cardioinhibitory preganglionic cells is discussed in relation to phylogenetic and ontogenetic development of the vagal motor nuclei.

A cooperative clinical trial of high-dose immunoglobulin therapy in 177 cases of idiopathic thrombocytopenic purpura.

A study was conducted with the cooperation of 31 university hospitals and 44 general hospitals in Japan on high-dose immunoglobulin therapy for idiopathic thrombocytopenic purpura (ITP). Sulfonated immunoglobulins were administered to 177 patients, comprising 102 children and 75 adults for two to seven days, and a favorable rise of platelet count was found in 114 (64.4%) of these patients. In particular, of the 107 patients who had not responded favorably to adrenocortico -steroids therapy, 63 cases showed a favorable rise of platelet count. And of the 14 patients who had not responded favorably to splenectomy, 6 cases showed a favorable rise of platelet count. In the majority of cases the platelet count fell to its pretreatment level within one month after the start of sequence of administration. Although a dosage of 400 mg/kg/day was suitable for most patients, the wide range of individual responses suggested the desirability of determining an optimal dose for each patients.

Effects of injected antibody against the platelet glycoprotein IIb/IIIa complex on monkey platelet fibrinogen.

Four monkeys were injected for a 10-day period with the Fab fragment of a murine monoclonal antibody (NNKY 1-32) which inhibits the binding of fibrinogen to the platelet glycoprotein (GP) IIb/IIIa complex. Platelet fibrinogen levels were assessed quantitatively by electroimmunoassay and qualitatively by immunoelectron microscopy. The platelet fibrinogen level fell to 9.0 +/- 2.8% of the control level after antibody administration. Immunoelectron microscopy showed that the injected antibody was localized on the inner surface of the platelet alpha-granule membrane. Our findings suggest that the GP IIb/IIIa complex can be internalized by alpha-granules and that it may mediate the endocytosis of plasma fibrinogen by platelets.

A new nitrosourea derivative for the treatment of chronic myelogenous leukemia.

A new water-soluble nitrosourea derivative, methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU), was found to be useful for the treatment of chronic myelogenous leukemia (CML) in the chronic phase. To compare the efficacy of MCNU with that of busulfan, patients were randomized. In the 40 patients administered MCNU, the median time to the achievement of a complete remission (CR) was 50 days. This value was shorter than that observed in 37 patients administered busulfan (126 days, p less than 0.05). There were no differences in the rate of CR achieved, mortality, median time to the onset of blast crisis (BC), BC rate, or survival rate during the observation period. The overall incidence of side effects was higher for MCNU (31%) than for busulfan (15%), but the symptoms were mild, transient and tolerable for most patients. These results suggest that MCNU is a safe and valuable addition to the therapeutic repertoire for the control of CML.

Anti-glycoprotein IIb/IIIa autoantibodies are reversibly internalized into platelets in idiopathic (autoimmune) thrombocytopenic purpura.

We used flow cytometry to investigate the binding of platelet-binding IgG (PBIgG) to unfixed platelets in idiopathic thrombocytopenic purpura (ITP), including that of anti-glycoprotein (GP) IIb/IIIa antibodies. Anti-GPIIb/IIIa antibodies were detected in 13/64 ITP patients using antigen-capture ELISA and immunoblotting. When unfixed platelets were incubated with ITP plasma, the PBIgG level was significantly higher than after incubation with normal plasma. When 1 microM ADP was added to unfixed platelets, which were incubated with ITP plasma and washed, the PBIgG level increased additively. GMP-140 is a constituent of platelet alpha-granules, and a monoclonal antibody directed against this protein showed weak binding to platelets after 1 microM ADP stimulation. The increase of PBIgG produced by ADP was significantly greater when ITP plasma positive for anti-GPIIb/IIIa antibody was used compared with that obtained using antibody-negative ITP plasma. This increase of PBIgG was markedly inhibited by the removal of extracellular calcium with EDTA or the dissociation of the GPIIb/IIIa complex by EDTA treatment at 37 degrees C. These results suggest that anti-GPIIb/IIIa autoantibodies are internalized by unfixed ITP platelets and stored somewhere other than the alpha-granules. This stored antibody pool can be reversibly redistributed on the platelet surface by weak stimulants such as ADP and a functional GPIIb/IIIa complex appears to be necessary for this to occur.

Polymorphonuclear leukocyte-platelet interactions: acetylglyceryl ether phosphocholine-induced platelet activation under stimulation with chemotactic peptide.

A mixture of rabbit polymorphonuclear leukocytes (PMNs) and platelets at concentrations of 5 X 10(6) PMN and 3.5 X 10(8) platelets/ml Tyrode's solution was stimulated with the chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (FMLP). A micromolar concentration of FMLP elicited an immediate weak aggregation, followed by a strong aggregation with a time lag of about 1 min. Microscopic examination showed that the immediate aggregation was due to PMNs and the delayed one was more complex and involved platelets. The delayed aggregation was dependent upon the concentrations of both the PMNs and FMLP. The delayed aggregation was completely blocked by pretreatment of the PMN-platelet mixture with 8 microM CV-3988, a specific receptor antagonist of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC), or by the application of platelets desensitized to AGEPC. The time course of AGEPC production by PMNs was well matched to that of the biphasic aggregation response. Furthermore, nordihydroguaiaretic acid inhibited both the AGEPC production by PMNs and the delayed aggregation in a similar dose-dependent manner. These result demonstrate that AGEPC, newly-generated by PMNs under FMLP-stimulation, is of primary importance in platelet aggregation in a PMN-platelet mixed system.

Application of selected ion monitoring to determination of platelet-activating factor.

The selected ion monitoring (SIM) technique was applied to determination of platelet-activating factor (PAF) or acetyl glyceryl ether phosphorylcholine (AGEPC). Two types of PAF, 1-hexadecyl- and 1-octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (C16 = 0 AGEPC and C18 = 0 AGEPC), were found in human neutrophils on the challenge with ionophore A23187. The contents of C16 = 0 AGEPC in 1 X 10(7) neutrophil cells of four volunteers, respectively, were 47, 18, 59, and 73 ng and those of C18 = 0 AGEPC were 22, 4, 19, and 31 ng.

Efficacy of sulbactam/cefoperazone for the treatment of infections in patients with hematologic diseases.

The efficacy and safety of sulbactam/cefoperazone (SBT/CPZ) was studied in 94 patients with severe infections and concomitant hematologic diseases. All of the study patients were included in the evaluation for safety, and 76 cases were evaluable for efficacy. Clinical efficacy was excellent in 13 cases (17.1%), good in 27 cases (35.5%), fair in seven cases (9.2%), and poor in 29 cases (38.2%). The bacteriologic eradication was 66.7% for Gram-negative bacilli and 50.0% for Gram-positive bacteria. The efficacy rate for neutropenic patients with counts less than 50 mm3 and 100 mm3 were 47.5 and 42.9%, respectively. Efficacy in patients for whom other antibiotic therapy before treatment with SBT/CPZ had been ineffective was 46.2%. Side effects were reported in one case (1.1%), and abnormal serum liver tests in five cases (5.3%); both returned to normal after discontinuation of the study medication. SBT/CPZ was an effective antibiotic for the treatment of severe infections in the presence of concurrent hematologic diseases.

Plasma coagulation and fibrinolysis parameters in patients with collagen diseases, and analysis of the multimeric structure of von Willebrand factor (vWF).

We studied the relationship between vascular complications and coagulation and fibrinolysis parameters in 75 subjects with collagen diseases. Thirty normal healthy persons served as controls. We found that patients with collagen diseases were in a state of a hypercoagulation and hyperfibrinolysis. In SLE (systemic lupus erythematosus) in particular, coagulation and fibrinolysis parameters appeared to be indices of vascular complications. Increases in the levels of thrombin-antithrombin III complex (TAT) and alpha 2-plasmin inhibitor-plasmin (PIP) were particularly associated with proteinuria, while increases in fibrinopeptide A (FPA) levels were associated with Raynaud's phenomenon. Administration of glucocorticoid seemed to improve the hypercoagulation and hyperfibrinolytic states of patients with collagen diseases. Analysis of the multimeric structure of von Willebrand factor (vWF) revealed a tendency for large and intermediate multimers (LIM) of plasma vWF to increase in SLE patients with accompanying vascular complications, whereas such increases were not observed in SLE patients without any vascular complications. Therefore, analysis of the multimeric structure of vWF appeared to be a useful indicator of vascular complications in collagen diseases.

Expression of platelet alpha-granule proteins in a human megakaryocytic leukemia cell line (CMK 11-5).

We investigated the expression of three platelet alpha-granule proteins, thrombospondin (TSP), von Willebrand factor (vWF), and fibrinogen (Fbg), in a human megakaryocytic cell line (CMK 11-5) by immunocytochemical staining, using the alkaline phosphatase anti-alkaline phosphatase (APAAP) complex method and immunoelectron microscopy of ultrathin-frozen sections. CMK 11-5, established from a Down's syndrome patient with acute megakaryoblastic leukemia, has characteristics closely resembling those of normal megakaryocytes. Under basal conditions, TSP expression was observed in the alpha-granules, whereas the other two proteins were not detected. When the cells were cultured with 12-o-tetradecanoylphorbol-13-acetate (TPA), the expression of TSP was enhanced and vWF was also detected, but not Fbg. Cells cultured in the presence of plasma for 24 h took up Fbg and stored it in their alpha-granules. These findings suggest that TSP and vWF are synthesized by CMK 11-5 cells, with the former being produced more rapidly than the latter, whereas Fbg is endocytosed from the plasma.

High-dose intravenous gamma globulin reduces macrophage colony-stimulating factor levels in idiopathic thrombocytopenic purpura.

We investigated the effect of high-dose intravenous gamma globulin therapy on the plasma level of macrophage-colony stimulating factor (M-CSF) level in 13 patients with chronic idiopathic thrombocytopenic purpura. M-CSF and interleukin-6 levels were determined by enzyme-linked immunosorbent assay. The mean +/- S.D. level of M-CSF in the patients was 1235 +/- 439 U/ml, and the level in 8 patients was higher than the mean + S.D. (903.6 U/ml) in normal controls. All 8 patients had steroid-refractory disease. M-CSF levels were significantly correlated with the serum levels of interleukin-6 (r = 0.66, P < 0.05). Interleukin-6 levels were also significantly raised in the high M-CSF group compared with the normal M-CSF group (P < 0.05). In the whole patient population, M-CSF levels decreased, but not significantly, after intravenous gamma globulin, while interleukin-6 decreased significantly. However, in the patients with high pretreatment M-CSF levels, both M-CSF and interleukin-6 decreased significantly after treatment (M-CSF, 4 weeks, P < 0.05; IL-6, 1 week, P < 0.05, 4 weeks, P < 0.01). These findings suggest that high-dose intravenous gamma globulin causes thrombocytosis by the decrease of M-CSF levels in idiopathic thrombocytopenic purpura.

Inhibition of platelet aggregation by low concentrations of sodium fluoride. Significance of the intracellular calcium ion concentration.

Sodium fluoride activates platelets but its mechanism of action has not yet been completely identified. We examined the effect of a low concentration of sodium fluoride (which could not cause aggregation) on thrombin-induced changes in the intracellular calcium ion concentration ([Ca2+]i). In the presence of 1 mM extracellular Ca2+, preincubation with a low concentration of sodium fluoride decreased the peak of the thrombin-induced elevation of [Ca2+]i, when measured with aequorin. When [Ca2+] was measured using fura-2, preincubation caused no marked changes in its peak, but the later changes that were thought to mainly reflect extracellular Ca2+ influx were inhibited. The inhibitory mechanism of sodium fluoride appears to depend on reducing extracellular Ca2+ influx. Aequorin appears to reflect [Ca2+]i near the cell membrane and is thus easily affected by the extracellular Ca2+ influx.

Ultrastructural analysis of platelet-like particles from a human megakaryocytic leukemia cell line (CMK 11-5).

Ultrastructural observations were performed to further characterize the human megakaryocytic leukemia cell line, CMK, and its subclone, CMK11-5. We found that particles derived from CMK11-5 cells had cytoplasmic projections and no nucleus, and that some particles contained alpha granules. Incubation with ADP induced fibrinogen receptors on the surface of these particles. Furthermore, the particles had glycoprotein Ib antigen on their surfaces, and attached nonreversibly to rabbit aortic subendothelium, showing associated morphological changes similar to those observed in normal platelets. CMK and CMK11-5 are the first megakaryocytic cell lines that have been found to release particles that have some of the same functions as normal platelets. In particular, CMK11-5 seems to be a useful model for studying megakaryocyte function.

Flow cytometric analysis of surface membrane proteins on activated platelets and platelet-derived microparticles from healthy and thrombasthenic individuals.

We used flow cytometry to investigate surface membrane protein expression by platelets and platelet-derived microparticles from normal individuals and a patient with Glanzmann's thrombasthenia. Microparticles were detected by both forward scatter and side scatter using FACScan. The binding of coagulation factors on microparticles was investigated by using monoclonal anti-Factor IX (IXa) and anti-Factor X (Xa) antibodies. Furthermore, the procoagulant activity of microparticles was measured with a chromogenic substrate (S-2222) using a microtiter enzyme-linked immunosorbent assay. Both types of platelets showed similar release of microparticles. Microparticles released from platelets after activation with the calcium ionophore A23187 did not bind factors IXa and Xa, but when purified factors Va and Xa were added to the incubation buffer, factor Xa binding increased markedly in both normal and thrombasthenic platelets. Both normal and thrombasthenic platelets showed a similar time-dependent release of microparticles when activated with A23187. However, the binding of an antibody to granule membrane protein-140 also increased time-dependently in normal microparticles, but was little increased in thrombasthenic microparticles. These findings suggest that glycoprotein IIb/IIIa does not participate in the expression of prothrombinase activity on the surface of activated platelets and microparticles, whereas this glycoprotein appears to have an important role in the movement of granule membrane protein-140 from platelets to microparticles.