26
|
Ma SW, Zhao DL, Yin ZQ, Mukherjee R, Singh B, Qin HY, Stiller CR, Jevnikar AM. Transgenic plants expressing autoantigens fed to mice to induce oral immune tolerance. Nat Med 1997; 3:793-6. [PMID: 9212110 DOI: 10.1038/nm0797-793] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Oral administration of protein can induce antigen-specific immune hyporesponsiveness. However, the utility of oral tolerance to autoantigens in the treatment of autoimmune diseases may be limited when candidate autoantigens cannot be produced by conventional systems in quantities sufficient for clinical studies. Plants may be ideally suited for this purpose, as they can synthesize, glycosylate and assemble mammalian proteins to provide huge quantities of relatively low cost soluble proteins. Furthermore, edible transgenic plants could provide a simple and direct method of autoantigen delivery for oral tolerance. Therefore, the aim of this study was to determine whether a transgenic plant expression system was capable of synthesizing the diabetes-associated autoantigen, glutamic acid decarboxylase (GAD) in an immunogenic form and whether the oral administration of an autoantigen expressed by a plant could directly induce protective immune responses in a mouse model of diabetes. We show that a GAD-expressing transgenic plant, given as a dietary supplement, inhibits the development of diabetes in the non-obese diabetic (NOD) mouse.
Collapse
|
27
|
Lai J, Ma SW, Porreca F, Raffa RB. Tramadol, M1 metabolite and enantiomer affinities for cloned human opioid receptors expressed in transfected HN9.10 neuroblastoma cells. Eur J Pharmacol 1996; 316:369-72. [PMID: 8982709 DOI: 10.1016/s0014-2999(96)00770-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tramadol hydrochloride is a centrally acting synthetic analgesic in widespread clinical use. Despite different degrees of opioid-like characteristics in preclinical tests, it is characterized by lack of full naloxone reversibility or naloxone-precipitated withdrawal in humans. To investigate this apparent discrepancy, the present study measured the affinity of tramadol (and its enantiomers) and an active O-desmethyl metabolite (M1) (and its enantiomers) to cloned human opioid receptors of the mu, delta and kappa type stably expressed in HN9.10 neuroblastoma cells. At mu sites, the Ki values for tramadol, its (+) and (-) enantiomers, M1, and its (+) and (-) enantiomers were 17000, 15700, 28800, 3190, 153 and 9680 nM, respectively, compared to 7.1 nM for morphine. These results are consistent with the suggestion of a non-opioid contribution to the clinical profile of tramadol.
Collapse
|
28
|
Lai J, Ma SW, Zhu RH, Rothman RB, Lentes KU, Porreca F. Pharmacological characterization of the cloned kappa opioid receptor as a kappa 1b subtype. Neuroreport 1994; 5:2161-4. [PMID: 7865767 DOI: 10.1097/00001756-199410270-00043] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Substantial pharmacological evidence in vitro and in vivo has suggested the existence of subtypes of the kappa opioid receptor. Quantitative radioligand binding techniques resolved the presence of two high affinity binding sites for the kappa 1 ligand [3H]U69,593 in mouse brain membranes, termed kappa 1a and kappa 1b, respectively. Whereas the kappa 1a site has high affinity for fedotozine and oxymorphindole and low affinity for bremazocine and alpha-neoendorphin, site kappa 1b has high affinity for bremazocine and alpha-neoendorphin and low affinity for fedotozine and oxymorphindole. CI-977 and U69,593 bind equally well at both sites. To determine the relationship between these kappa 1 receptor subtypes and the recently cloned mouse kappa 1 receptor (KOR), we examined [3H]U69,593 binding to the KOR in stably transfected cells (KORCHN-8). Competition of [3H]U69,593 binding to the KOR by bremazocine, alpha-neoendorphin, fedotozine and oxymorphindole resolved a single class of binding sites at which these agents had binding affinities similar to that of the kappa 1b site present in mouse brain. These results suggest that the cloned KOR corresponds to the kappa 1 site in mouse brain defined as kappa 1b.
Collapse
|
29
|
Liang DC, Ma SW, Lu TH, Lin ST. Transient myeloproliferative disorder and acute myeloid leukemia: study of six neonatal cases with long-term follow-up. Leukemia 1993; 7:1521-4. [PMID: 8412314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Six neonates with hematological and clinical pictures indistinguishable from acute myeloid leukemia were studied. Two patients had Down syndrome and three others had either +21 or i(21q) chromosomal abnormalities in their blood cells at presentation. Granulocyte-macrophage colony-forming unit assays performed in bone marrow and peripheral blood mononuclear cells revealed abnormal growth patterns in two patients; both died of progressive disease of acute myeloid leukemia. All the other four neonates with normal in vitro cell growth pattern had spontaneous remission within 7 months. Of these four patients, one remains well and in remission for 8 years and the other three developed acute myeloid leukemia at the ages of 15, 32 and 19 months, respectively. We conclude that the in vitro cell growth pattern is helpful to distinguish transient myeloproliferative disorder from congenital acute myeloid leukemia and that patients with the former condition are at risk to develop acute myeloid leukemia subsequently.
Collapse
MESH Headings
- Acute Disease
- Cell Division/physiology
- Colony-Forming Units Assay
- Diagnosis, Differential
- Female
- Follow-Up Studies
- Granulocytes/cytology
- Humans
- Infant
- Infant, Newborn
- Leukemia, Myeloid/diagnosis
- Leukemia, Myeloid/etiology
- Leukemia, Myeloid/pathology
- Leukemia, Myeloid, Acute/diagnosis
- Leukemia, Myeloid, Acute/etiology
- Leukemia, Myeloid, Acute/pathology
- Leukemia, Myelomonocytic, Acute/diagnosis
- Leukemia, Myelomonocytic, Acute/etiology
- Leukemia, Myelomonocytic, Acute/pathology
- Macrophages/cytology
- Male
- Myeloproliferative Disorders/complications
- Myeloproliferative Disorders/epidemiology
- Myeloproliferative Disorders/pathology
- Risk Factors
- Time Factors
Collapse
|
30
|
Ma SW, Corsaro BG, Klebba PE, Fraser MJ. Cloning and sequence analysis of a p40 structural protein gene of Helicoverpa zea nuclear polyhedrosis virus. Virology 1993; 192:224-33. [PMID: 8517018 DOI: 10.1006/viro.1993.1025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A gene encoding an occluded virion structural protein was isolated from an expression library constructed from the Helicoverpa zea S-type nuclear polyhedrosis virus (NPV) isolate HzS-15 using both polyclonal and monoclonal antibody screening. The gene was located within a Pstl-Sall fragment of the HzS-15 genome spanning from 96.5 to 97.3 m.u. Sequencing analyses revealed a long open reading frame of 927 nucleotides that predicted a protein of 37 kDa in size. Immunoblot analyses using the monoclonal antibody ENV409 demonstrated that the gene corresponded to a 40-kDa protein (p40) in SDS-polyacrylamide gels that was present exclusively in enveloped occluded virions but not in extracellular budded virions or envelope-stripped nucleocapsids. A p40 protein-specific transcript was detected at 16 hr postinfection in HzS-15-infected Hz 1075/UND-K cells and remained until 22 hr. Primer extension analyses demonstrated that the p40 protein-specific transcript started at -49 nucleotides from the ATG start codon within an ATAAG consensus pentamer found in late protein genes of Baculoviruses. The deduced amino acid sequence of the HzS-15 p40 protein gene shared 44 and 45% sequence homology with the p40 proteins of Bombyx mori NPV and Autographa californica NPV, respectively.
Collapse
|
31
|
Lai J, Nunan L, Waite SL, Ma SW, Bloom JW, Roeske WR, Yamamura HI. Chimeric M1/M2 muscarinic receptors: correlation of ligand selectivity and functional coupling with structural modifications. J Pharmacol Exp Ther 1992; 262:173-80. [PMID: 1625198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Chimeric M1/M2 receptors were expressed in murine fibroblasts (B82) transfected with recombinant m1/m2 receptor genes. The binding affinities of a number of muscarinic antagonists and the agonist carbachol for these chimeric receptors were compared with the ligands' affinities for the M1 and M2 receptors expressed in the B82 cells. The tricyclic compounds, namely pirenzepine (PZ), 11-([2-[(diethylamino)methyl]-1-piperidinyl]acetyl)-5,11- dihydro-6H-pyrido-[2,3-6][1,4]benzodiazepine-6-one (AF-DX 116) and himbacine, shared a binding site between transmembrane domains VI and VII. However, the selective interaction of pirenzepine with M1 and AF-DX 116 and himbacine with M2 involved different structural regions. The high-affinity binding for 4-diphenylacetoxy-N- methylpiperidine and hexahydrosiladifenidol was confined to within loop o2 and transmembrane domains V and VI, which were clearly distinguishable from those of the tricyclic compounds. These results support the hypothesis that the ligands' stereochemical features are critical in their optimal alignment within the ligand binding pocket. The cytoplasmic i3 loop modulated the binding of carbachol such that receptors which contained the i3 domain from the M2 receptor exhibited a single high-affinity state, whereas those with the i3 domain from the M1 receptor had an additional low-affinity state for the agonist. The i3 regions are essential for the differential functional coupling of the M1 and M2 receptors to second messenger systems; however, additional upstream regions seem to be essential for a potent and efficacious activation of phospholipase C by the M1 receptor. This study provides new insight into the molecular basis of ligand selectivity.
Collapse
|
32
|
Ma SW, Preston E. Disparate effects of fenfluramine on thermogenesis in brown adipose tissue in the rat. Can J Physiol Pharmacol 1992; 70:214-8. [PMID: 1521178 DOI: 10.1139/y92-026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It has been suggested that fenfluramine, a clinically used appetite suppressant, can also promote weight loss by augmenting energy expenditure, as indicated by increased whole-body O2 consumption (VO2) and mitochondrial GDP binding in brown adipose tissue (BAT) of fenfluramine-treated rats. To further investigate a possible involvement of BAT in the drug's metabolic effects, 113Sn-labelled microspheres were injected into the left cardiac ventricle of conscious rats 70-80 min after intraperitoneal delivery of 20 mg/kg fenfluramine (DL-mixture) or saline vehicle. At 28 degrees C ambient temperature, fenfluramine augmented resting whole-body VO2 and increased the microsphere entrapment in BAT, indicating enhanced blood flow and metabolism. At 20 degrees C ambient temperature, the expected increase in BAT blood flow associated with nonshivering thermogenesis was observed in control rats, but in fenfluramine-treated rats the increase in BAT blood flow was severely attenuated, and VO2 and body temperature were reduced. The stimulatory effect of fenfluramine on BAT metabolism was not prevented by urethane anesthesia but did not occur if the tissue was denervated. These blood flow measurements corroborate previous reports, based on GDP-binding assays, that fenfluramine treatment can augment thermogenesis in BAT by effects mediated through the innervation of the tissue. However, the data also indicate that this calorigenic effect is dependent on ambient temperature being near thermoneutrality and that in a cool environment the drug inhibits BAT thermogenesis.
Collapse
|
33
|
Zhao Y, Shen Y, Liu Y, Zhang JC, Ye LZ, Ma SW, Lo WH, Wu GY, Cheng ZY, Zhang XZ. Fragile X syndrome (Martin-Bell syndrome) in China. AMERICAN JOURNAL OF MEDICAL GENETICS 1991; 38:288-9. [PMID: 2018073 DOI: 10.1002/ajmg.1320380224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
34
|
Ma SW, Iyer VN. New Field Isolates of
Rhizobium leguminosarum
Biovar Viciae That Nodulate the Primitive Pea Cultivar Afghanistan in Addition to Modern Cultivars. Appl Environ Microbiol 1990; 56:2206-12. [PMID: 16348240 PMCID: PMC184584 DOI: 10.1128/aem.56.7.2206-2212.1990] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A collection of 13 field isolates of
Rhizobium leguminosarum
bv. viciae that have the ability to nodulate the roots of current North American cultivars of peas as well as a “primitive” cultivar, Afghanistan, was examined. These isolates originated in diverse geographical regions of the world, which indicates that this phenotype is not restricted to isolates from any one region. When subclones of the nodulation region from one plasmid were used to examine
Eco
RI-fragment-length polymorphisms in this collection of strains as well as in a collection comprising strains that do not nodulate the primitive cultivar, polymorphism was found in both collections. With one exception, RisφA6, all strains that nodulated cv. Afghanistan pea contained a region called
nodX
as an extension to the
nodA BCIJ
operon that has been observed in all
R. leguminosarum
bv. viciae strains, including those that do not nodulate cv. Afghanistan pea. RisφA6 was also the only strain in which nodulating ability could not be associated with a conjugative plasmid.
Collapse
|
35
|
Ma SW, Foster DO. Brown adipose tissue, liver, and diet-induced thermogenesis in cafeteria diet-fed rats. Can J Physiol Pharmacol 1989; 67:376-81. [PMID: 2758378 DOI: 10.1139/y89-061] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Diet-induced thermogenesis (DIT) in young rats overeating a "cafeteria" (CAF) diet of palatable human foods is characterized by a chronic, propranolol-inhibitable elevation in resting metabolic rate (VO2) and is associated with various changes in brown adipose tissue (BAT) that have been taken as evidence for BAT as the effector of DIT. But direct evidence for participation of BAT in DIT has been lacking. By employing a nonocclusive cannula to sample the venous effluent of interscapular BAT (IBAT) for analysis of its O2 content and measuring tissue blood flow with microspheres, we accomplished direct determination (Fick principle) of the O2 consumption of BAT in conscious CAF rats. In comparison with normophagic controls fed chow, the CAF rats exhibited a 43% increase in metabolizable energy intake, reduced food efficiency, a 22% elevation in resting VO2 at 28 degrees C (thermoneutrality) or 24 degrees C (housing temperature), and characteristic changes in the properties of their BAT (e.g., increased mass, protein content and mitochondrial GDP binding). They also exhibited the greater metabolic response to exogenous noradrenaline characteristic of CAF rats and the near elimination by propranolol of their elevation in VO2. By the criterion of their elevated VO2, the CAF rats were exhibiting DIT at the time of the measurements of BAT blood flow and blood O2 levels. However, BAT O2 consumption was found to be no greater in the CAF rats than in the controls at either 28 or 24 degrees C. At 28 degrees C it accounted for less than 1% of whole body VO2; at 24 degrees C it increased to about 10% of overall VO2 in both diet groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
36
|
Liang DC, Ma SW, Lin-Chu M, Lan CC. Granulocyte/macrophage colony-forming units from cord blood of premature and full-term neonates: its role in ontogeny of human hemopoiesis. Pediatr Res 1988; 24:701-2. [PMID: 3205625 DOI: 10.1203/00006450-198812000-00010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
It is still uncertain whether the yolk sac is the only origin of hemopoietic stem cells during fetal development. We studied the level of circulating granulocyte/macrophage colony-forming unit (CFU-GM) from the 23rd week of gestation to fullterm, trying to delineate its role in the ontogeny of human hemopoiesis. Cord blood samples were collected from 45 healthy premature neonates and 91 healthy full-term neonates. CFU-GM assays were performed using a single agar layer system with human placental conditioned medium as a source of colony stimulating activity. The mean numbers of colonies produced from the cord blood samples of the premature and full-term neonates were 116 +/- 185 (SD) and 96 +/- 113/2 x 10(5) mononuclear cells, respectively. There was no statistical difference between the numbers of colonies of the two groups (Mann-Whitney test, p greater than 0.05). These results indicate that the level of circulating CFU-GM from the 23rd week of gestation to full term is constantly high and add credence to the assumption that CFU-GM are produced not only from the yolk sac but also from other hemopoietic sites.
Collapse
|
37
|
Ma SW, Foster DO, Nadeau BE, Triandafillou J. Absence of increased oxygen consumption in brown adipose tissue of rats exhibiting "cafeteria" diet-induced thermogenesis. Can J Physiol Pharmacol 1988; 66:1347-54. [PMID: 3242772 DOI: 10.1139/y88-221] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Young male Sprague-Dawley rats were induced to overeat (approximately 45%) by provision of a "cafeteria" (CAF) diet of palatable human foods. Normophagic rats fed a commercial chow or a semisynthetic diet served as controls. The CAF rats exhibited (a) the reduced food efficiency and the propranolol-inhibitable elevation in resting metabolic rate (resting VO2) that are indicative of a facultative diet-induced thermogenesis (DIT) by which excess energy gain is resisted, and (b) certain changes in brown adipose tissue (BAT) that are among those taken as evidence for BAT as the effector of DIT, e.g., increased protein content and increased mitochondrial binding of GDP. To assess directly and quantitatively the contribution by BAT to the elevation in VO2 (apparent DIT) of the CAF rats, BAT O2 consumption was determined (Fick principle) from measurements of tissue blood flow (microsphere method) and the arteriovenous difference in blood O2 across interscapular BAT (IBAT). To obtain the measurements, the animals were fitted under halothane anesthesia with vascular cannulas for intraventricular injection of microspheres and sampling of arterial blood and the venous effluent of IBAT. After recovery from anesthesia and rewarming to normal body temperature the animals were placed singly in a temperature-controlled metabolic chamber and the measurements, which also included determination of resting VO2, were made 1.5-2 h later about 11:30 h. As determined from measurements made at 28 degrees C (thermoneutrality) mean values of resting VO2 for the cannulated rats were unchanged from those of intact (unoperated) CAF or control rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
38
|
Liang DC, Ma SW. A simple and rapid in situ staining method for granulocyte-macrophage colonies in agar culture. INTERNATIONAL JOURNAL OF CELL CLONING 1988; 6:25-9. [PMID: 2448395 DOI: 10.1002/stem.5530060104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This report describes a very simple, quick and effective method for in situ staining of granulocyte-macrophage colonies in agar cultures and for classifying various colony types. The procedure takes only one minute to fix and a few minutes to stain; a few additional minutes are required for preparation of the permanent whole plate. In this process the Riu stain, a modified Romanowsky stain, is used. Besides the ease and rapidity of this procedure, the identification of colony types appears to be enhanced. Thus, the method seems to be very beneficial in routine observations of colony types.
Collapse
|
39
|
Li ZW, Wang XC, Ma SW, Wang J, He SF. Clinical and histopathologic findings in osteoarticular chronic hypertrophic neuritis and differentiation from leprosy. INTERNATIONAL JOURNAL OF LEPROSY AND OTHER MYCOBACTERIAL DISEASES : OFFICIAL ORGAN OF THE INTERNATIONAL LEPROSY ASSOCIATION 1987; 55:556-9. [PMID: 3655468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
40
|
Ma SW, Nadeau BE, Foster DO. Evidence for liver as the major site of the diet-induced thermogenesis of rats fed a "cafeteria" diet. Can J Physiol Pharmacol 1987; 65:1802-4. [PMID: 3690401 DOI: 10.1139/y87-281] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The resting metabolic rates (VO2) of rats fed chow (CH) or a "cafeteria" (CAF) diet of highly palatable human foods were measured at thermoneutrality (28 degrees C) before and shortly after two-thirds hepatectomy or sham operation, and again after administration of propranolol (5 mg/kg). CAF rats initially had a 17% and 1.2 mL/min higher mean resting VO2 than CH rats, a difference usually considered to represent the diet-induced thermogenesis (DIT) that CAF rats develop during overconsumption of the diet. Sham operation did not significantly affect resting VO2 in either diet group. Two-thirds hepatectomy decreased VO2 by about 1.0 mL/min more (125% more) in CAF rats than in CH rats, from which it may be estimated that the CAF rats initially had a liver VO2 about 1.6 mL/min higher than that of the CH rats, a difference more than sufficient to fully account for their apparent DIT. Propranolol did not significantly affect the VO2 of CH rats. It reduced the VO2 of sham-operated CAF rats by 0.94 +/- 0.08 mL/min (12%), but had a significantly smaller effect (delta VO2 = -0.50 +/- 0.05 mL/min) in partially hepatectomized CAF rats. This difference suggests that about 70% of the propranolol-inhibitable fraction of the elevated VO2 of the CAF rats, presumably a measure of sympathetically mediated DIT, resided in the liver. This study thus points to the liver as the major (70-100%) effector of the DIT of CAF rats.
Collapse
|
41
|
Ye LZ, Ma SW, Zhao Y, Li SH, Zhang JC, Sun NH, Luo HY. [Cytogenetic studies on 60 couples with habitual abortions]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1987; 9:226-8. [PMID: 2958163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
42
|
Zhao Y, Liu CY, Cheng ZY, Ye LZ, Gao CS, Ma SW, Zhang JC, Shi HP, Yuan LF, Luo HY. [Chromosome analysis of 1133 cases in genetic counseling clinic]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1987; 9:157-64. [PMID: 2958156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
43
|
Huo YS, Zhang SC, Zhou D, Yao DL, You GY, Zhang HW, Ma SW, Mo QZ, Gong B, Yi MG. [Pharmacokinetics and tissue distribution of [3H]ginsenoside Rg1]. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1986; 7:519-21. [PMID: 2955640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
44
|
Ma SW, Nadeau BE, Foster DO. A nonocclusive cannula for sampling venous blood from the interscapular brown fat of conscious rats. Can J Physiol Pharmacol 1986; 64:1434-9. [PMID: 3791044 DOI: 10.1139/y86-242] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Lack of an adequate method for sampling venous blood from the brown adipose tissue (BAT) of conscious animals has impeded study of the in vivo metabolism of this tissue during physiological activation of its thermogenic function. This paper describes a technique for cannulating the main vein (Sulzer's) of the interscapular BAT (IBAT) of rats in a manner that does not impair blood flow and allows multiple venous sampling over several hours in conscious animals. The technique was tested over the widest possible range of IBAT blood flows by applying it to measurements of IBAT arteriovenous O2 differences in barbital-anesthetized, cold-acclimated rats infused with vehicle or with various doses of noradrenaline. Comparison was made with controls in which samples of IBAT venous blood were obtained by cutting Sulzer's vein. Blood flow was measured by the microsphere method. These tests showed that the presence of the special cannula in Sulzer's vein had no significant effect on the blood flow, arteriovenous O2 difference, or O2 consumption of the IBAT at any level of noradrenaline-induced thermogenesis. The new technique will permit examination of the functioning of BAT in nonshivering thermogenesis and diet-induced thermogenesis under much more physiological conditions than hitherto possible. It should also significantly reduce the number of animals required for such studies.
Collapse
|
45
|
Ma SW, Foster DO. Starvation-induced changes in metabolic rate, blood flow, and regional energy expenditure in rats. Can J Physiol Pharmacol 1986; 64:1252-8. [PMID: 3779521 DOI: 10.1139/y86-211] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Starvation results in an energy-conserving reduction in metabolic rate that has features of an adaptive response. Tissue and organ sites of this response were investigated by examining the effects of starvation for 5 d on tissue blood flow (microsphere method) and regional arteriovenous O2 differences ((a-v)O2) in conscious rats resting quietly at 28 degrees C. Comparison was with fed and overnight-fasted animals. Whole body resting metabolic rates (MR), colonic temperatures (Tc), and tissue weights were also determined. Quantitative changes in energy expenditure (as O2 consumption) were obtained for two regions: the portal-drained viscera (PDV) and the hindquarters (HQ). Fasting overnight resulted in increased blood flow to white adipose tissue (WAT) and decreased flow to the brain, PDV, testes, and skin; however, MR, Tc, the two regional ((a-v)O2, and the weights of most tissues were not significantly altered. In comparison with overnight fasting, starvation for 5 d resulted in a 13% reduction in body weight, weight loss in many tissues and organs, a 26% reduction in MR, a decline of 0.5 degree C in Tc, decreased (a-v)O2 across both the PDV and HQ, reduced cardiac output, and decreased blood flow to the heart, PDV, skin, WAT, leg muscle, HQ, and the musculoskeletal body as a whole. Utilization of O2 by the PDV and HQ (flow X (a-v)O2) declined by amounts that accounted for 22 and 18%, respectively, of the reduction in MR. The reductions in cardiac output (18%) and heart blood flow (36%) indicate that the heart also made a contribution to energy conservation (roughly estimated as 5%).(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
46
|
Harris WH, Foster DO, Ma SW, Yamashiro S, Langlais-Burgess LA. The noradrenaline content and innervation of brown adipose tissue in the young rabbit. Can J Physiol Pharmacol 1986; 64:561-7. [PMID: 3730941 DOI: 10.1139/y86-093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This work examined the noradrenaline content of brown adipose tissue, the metabolic response to endogenous noradrenaline released during tyramine infusion, and the innervation of brown fat at the electron microscopic level in the young rabbit. The noradrenaline content (ng/g) of the interscapular and cervical fat deposits ranged from 256 +/- 51 to 343 +/- 59 and 399 +/- 18 to 694 +/- 92, respectively, in four groups of rabbits (1-2, 7-8, 12-13, and 25-27 days of age). There was considerable variation amongst animals in each age group, but no evidence of a major increase or decrease in noradrenaline content during the first 4 weeks of life. Intravenous infusion of tyramine (100 micrograms X kg-1 X min-1) increased plasma noradrenaline concentration, oxygen consumption, and blood flow to brown fat. Thus noradrenaline released from endogenous sites, as well as injected noradrenaline, will initiate the thermogenic response of brown fat. Ultrastructurally, unmyelinated axons that were not organized in a fascicle were observed adjacent to the adipocytes in the late gestation fetus. By 1 week of age of axons were surrounded by Schwann cell cytoplasm which formed a fascicle. However, no evidence of myelination was found up to 21 days of age. Collectively, the data indicate that the brown adipocyte is fully responsive at 1-2 days of age even though myelination of the nerves is incomplete, and that the incomplete development of the sympathetic nerves at birth is not a factor in the synthesis of noradrenaline in the very young rabbit. In addition, brown fat of the newborn rabbit is not as thermogenically active as the brown fat of the cold-acclimated rat.
Collapse
|
47
|
Ma SW, Foster DO. Uptake of glucose and release of fatty acids and glycerol by rat brown adipose tissue in vivo. Can J Physiol Pharmacol 1986; 64:609-14. [PMID: 3730946 DOI: 10.1139/y86-101] [Citation(s) in RCA: 137] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The net in vivo uptake or release of free fatty acids glycerol, glucose, lactate, and pyruvate by the interscapular brown adipose tissue (IBAT) of barbital-anesthetized, cold-acclimated rats was determined from measurements of plasma arteriovenous concentration differences across IBAT and tissue blood flow. Measurements were made without stimulation of the tissue and also during submaximal and maximal stimulation by infused noradrenaline (NA), the physiological activator of BAT thermogenesis. There was no appreciable uptake of glucose or release of fatty acids and glycerol by the nonstimulated tissue. At both levels of stimulation there was significant uptake of glucose (1.7 and 2.0 mumol/min) and release of glycerol (0.9 and 1.2 mumol/min), but only at maximal stimulation was there significant release of fatty acids (1.9 mumol/min). Release of lactate and pyruvate accounted for 33% of the glucose taken up at submaximal stimulation and 88% at maximal stimulation. By calculation, the remainder of the glucose taken up was sufficient to have fueled about 12% of the thermogenesis at submaximal stimulation, but only about 2% at maximal stimulation. As estimated from the rate of glycerol release, the rate of triglyceride hydrolysis was sufficient at submaximal stimulation to fuel IBAT thermogenesis entirely with the resulting fatty acids, but it was not sufficient to do so at maximal stimulation when some of the fatty acid was exported. It is suggested that at maximal NA-induced thermogenesis a portion of lipolysis proceeded only to the level of mono- and di-glycerides with the result that glycerol release did not fully reflect the rate of fatty acid formation.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
48
|
Ling LH, Ma SW, Tang MY, Gu CX, Shi YF, Jin ZM, Shao HX, Wu M. [Clinical manifestation and cytogenetic analysis of true hermaphroditism]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1986; 8:32-6. [PMID: 2943441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
49
|
Ma SW, Foster DO. Potentiation of in vivo thermogenesis in rat brown adipose tissue by stimulation of alpha 1-adrenoreceptors is associated with increased release of cyclic AMP. Can J Physiol Pharmacol 1984; 62:943-8. [PMID: 6149006 DOI: 10.1139/y84-158] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Release of cyclic AMP (cAMP) from the interscapular brown adipose tissue (IBAT) of barbital-anesthetized, cold-acclimated rats given activators and inhibitors of brown adipose tissue (BAT) thermogenesis was assessed by measuring IBAT blood flow (microsphere method) and the arteriovenous difference in plasma cAMP across the tissue. The release was taken as an index of the generation of cAMP in the IBAT. During thermogenesis induced by infusion of graded doses of noradrenaline (NA), release of cAMP increased from no significant release without NA to 68 pmol/min at a NA dose that effected maximal thermogenesis. The alpha-adrenoreceptor antagonist dihydroergotoxin inhibited NA-induced BAT thermogenesis and markedly reduced the release of cAMP. The alpha 1-adrenoreceptor agonist phenylephrine potentiated the in vivo thermogenic response of BAT to isoproterenol or to a suboptimal dose of NA and enhanced the release of cAMP elicited by these catecholamines. But given alone, phenylephrine or dihydroergotoxin had very little or no effect on thermogenesis and cAMP release. These results suggest that stimulation of the alpha 1-adrenoreceptors on BAT adipocytes potentiates the thermogenic response originating from stimulation of the adenylate cyclase-coupled beta 1-adrenoreceptors by increasing, in some indirect way, the generation of cAMP, the intracellular messenger for activation of thermogenesis. However, in the absence of proof that adipocytes are the principal source of the cAMP released from IBAT, during catecholamine-induced thermogenesis, this explanation for the effect of alpha 1-adrenoreceptor stimulation on thermogenesis remains tentative.
Collapse
|
50
|
Ma SW, Foster DO. Redox state of brown adipose tissue as a possible determinant of its blood flow. Can J Physiol Pharmacol 1984; 62:949-56. [PMID: 6488086 DOI: 10.1139/y84-159] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
During norepinephrine (NE) induced thermogenesis in the adipocytes of brown adipose tissue (BAT), the blood flow of the tissue, and thus its oxygen supply, seems to be controlled by the adipocytes, possibly through their production of a vasodilator. This study sought to discover a metabolic parameter of the adipocytes that might account for modulation of vasodilator production and BAT blood flow. The blood flow of the interscapular BAT (IBAT) of anesthetized, cold-acclimated rats was varied by infusing NE and by altering the concentration of oxygen in arterial blood (AO2). Flow was measured with radiolabeled microspheres. IBAT was freeze fixed in situ for determination of its levels of adenine nucleotides and its cytosolic redox state; the latter was measured in terms of the concentration ratios, lactate/pyruvate (L/P) and glycerol-3-phosphate/dihydroxyacetone phosphate (GP/DHAP) in the tissue. The increase in IBAT blood flow with dose of NE was associated with a progressive decline in tissue ATP, increases in ADP and AMP at high doses of NE, and progressive increases in L/P and GP/DHAP, the latter increases indicating increased reduction of the cytosolic NAD+-NADH system. Reducing AO2 by hemodilution raised the blood flow, L/P, and GP/DHAP of IBAT to values significantly above those measured in rats of normal AO2 given the same doses of NE; whereas, elevating AO2 by hemoconcentration had the opposite effects on these values. For rats of normal or altered AO2 together, a correlation coefficient of 0.94 was obtained for the relation between IBAT blood flow and L/P and one of 0.85 for that between flow and GP/DHAP.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|