Effects of anisodamine against myocardial ischemia-reperfused injuries and antilipid peroxidation

AIM

Anisodamine (Ani), an alkaloid first isolated in China. To study the relationship between the protective effects of Ani on myocardial cells of reperfused injuries and the antilipid peroxidation.

METHODS

Coronary ligation for 15-min followed by 10 min reperfusion was performed in anesthetized rats.

RESULTS

Ani 1, 3, 5 mg.kg-1 i.v. 1 min prior to reperfusion could dose-dependently lower the release of creatine kinase (282 +/- 29, 252 +/- 53, 226 +/- 50), counteract the increase of malondialdehyde content (3.3 +/- 1.3, 3.2 +/- 1.6, 3.1 +/- 1.2) in the reperfused myocardium and preserve the SOD activity (41 +/- 7, 46 +/- 8, 55 +/- 8). Ani completely abolished the drop in the contents of principal unsaturated fatty acids (oleic, linoleic, and arachidonic acids) of the membrane lipids in the reperfused myocardium. SOD 75 U.kg-1 i.v. 1 min prior to reperfusion exerted similar effects like Ani 3 mg.kg-1.

CONCLUSION

It is suggested that the antilipid peroxidative effect of Ani may contribute to its protection against reperfusion-induced myocardial injuries.

Retinoic acid antagonizes basal as well as coal tar and glucocorticoid-induced cytochrome P4501A1 expression in human skin

Cytochrome P4501A1 is known to be expressed in skin and thus has been implicated in the pathogenesis of skin cancer due to certain environmental carcinogens. Retinoic acid (RA) has been used in chemoprevention of certain skin and other epithelial cancers. Therefore, we used Northern and Western analysis to determine the effect of externally applied RA on basal P4501A1 expression. RA reduced basal levels of P4501A1 mRNA and protein by 68 (n = 14, P = 0.005) and 75% (n = 7, P = 0.04) respectively. RA application also reduced basal levels of P4501A2 (another P4501A1 subfamily member) mRNA by 93% (n = 7, P = 0.001) as determined by reverse transcription-polymerase chain reaction. Interestingly, P4501A1 mRNA expression induced by coal tar or glucocorticoid (clobetasol) was reduced 46 (n = 10, P = 0.003) and 69% (n = 5, P < 0.05) respectively by RA co-application. Downregulation of basal P4501A1 expression and antagonism of coal tar mediated P4501A1 induction by RA may be a mechanism involved in chemo-prevention of skin and other epithelial cancer by RA.

Immunomodulating effects of morphine microinjected into periaqueductal gray

AIM

To study the effects of morphine on immune system through rat brain periaqueductal gray (PAG).

METHODS

Three hours after microinjection of morphine through the implanted steel tubes to PAG, splenic cytokines interleukin 2 (IL-2), interleukin 6 (IL-6), tumor necrosis factor (TNF), and natural killer cells (NK) activity were measured.

RESULTS

Microinjection of morphine (0.5 microL, 3672 ng) into PAG region had no influence on IL-6 and TNF-alpha (production of splenic macrophages, suppressed the natural killer cell (NK) activity and enhanced T-lymphocyte functions, including concanavalin A (Con A)-induced T-cell proliferation, IL-2 and TNF-beta production. Both the suppressive and stimulating actions were blocked by PAG preinjection of the mu opioid receptor antagonist naloxone (0.5 microL, 1 microgram), which alone showed the contrary effect to morphine.

CONCLUSION

Morphine affected immunofunctions through opioid receptors in PAG, and the influences on various immunocompetent cells were different.

[Tyr-D-Ala-Gly-Phe-D-Leu (DADL) solid-phase synthesis and its effects on immune function]

DADL, a delta-receptor selective enkephalin analogue, was prepared with the technique of solid-phase peptide synthesis. It was found to stimulate directly the proliferation of mouse splenic lymphocytes dose-dependently. However, synergistic effect of DADL at different concentrations with ConA and LPS were not found. In addition, TNF-alpha production was increased by ip DADL (1.0 mg.kg-1 x 6 d) in mice and the production of LPS-induced TNF-alpha in mouse peritoneal macrophages was enhanced after DADL was added in vitro. These results suggest that DADL, like enkephalins, exerts some immunoregulatory activities.

[Electron microscopic observation of the denervated flap reinnervation after implantation of sensory nerve]

Flap reinnervation was studied by electron microscopy in the rabbit cervico-shoulder flap with great auricular nerve implanted. After transferring the flap to the dorsal defect of the rabbit's ear and division of its pedicle, the original nerve fibers of the flap underwent a degenerative process which would persist over 2 months. The great auricular nerve implanted into the flap regenerated axons by entering into old endoneurial rube of the flap and sprouting. The development process of the regenerating nerves showed that the unmyelinated fibers appeared first in the 2nd month, and the myelinated ones in the 4th month. The regenerating nerve fibers had often accompanied by blood vessels.

[Detection of Mycobacterium tuberculosis using a nested-primer gene amplification assay]

A nested-primer gene amplification assay (NPGAA) was established by using two pairs of primers, an outside pair of primers and an inside pair of primers, sequences of which were from M. tuberculosis(Mtb) gro EL genes. The outside pair of primers should amplify a 576-bp piece of the Mtb gro EL gene that contains sites for the inside pair of primers, which should amplify a 344-bp piece. The results shows NPGAA'S detectable limitation was 1 organism/ml and no amplification products were produced from DNAs of other mycobacterium species tested in this study. For detecting Mtb, the entire NPGAA, from sample preparation to data analysis, can be completed within 6-8 hours. When identifying AFB cultures isolated from lesions of skin diseases, the same positive size patterns were obtained.

Dominant negative analogs of NF-YA

NF-Y is a highly conserved heteromeric CCAAT-binding transcription factor involved in the function of several promoters. The NF-YA subunit contains a domain of high homology to yeast HAP2, which we show to be necessary and sufficient to mediate interactions with the NF-YB subunit and with DNA. Using protein affinity columns derivatized with amino acid substitution mutants, we further dissect this region into two functionally separable subdomains. The subunit association function resides in a 21-amino acid stretch, which is almost perfectly conserved among different species, while interaction with DNA resides in another short segment. We also show that DNA-binding mutants act as dominant repressors of NF-Y-DNA complex formation and of NF-Y-dependent transcription.

An investigation of the role of glutathione in increased epithelial permeability induced by cigarette smoke in vivo and in vitro

Airspace epithelial permeability is known to increase in cigarette smokers. To study the role of the antioxidant reduced glutathione (GSH) in this phenomenon, we used an in vitro model of the epithelial permeability of a monolayer of human type II alveolar epithelial cells (A549 cell line). Both whole (WSC) and vapor (VSC) smoke condensates induced a recoverable, concentration-dependent increase in epithelial permeability to 125iodine-labeled bovine serum albumin (125IBSA), associated with a profound fall in intracellular GSH. Buthionine sulfoximine (BSO), a GSH synthesis inhibitor, decreased GSH levels in A549 epithelial cells, significantly increased A549 epithelial cell permeability, and enhanced both WSC and VSC-induced A549 epithelial cell permeability. Co-culturing epithelial cells and GSH (500 microM) reduced WSC-induced, but not VSC-induced A549 epithelial cell permeability. Increasing intracellular GSH also ameliorated the smoke-induced increased epithelial permeability. Concentrations of cigarette smoke condensate of < 20% increased A549 epithelial cell permeability without associated cell detachment and lysis, which was also the case with BSO-induced increased epithelial permeability. WSC and VSC, instilled intratracheally, significantly increased rat lung epithelial permeability to 125IBSA, 6 h postinstillation, associated with a significant recruitment of neutrophils into the airspaces. This was associated with a small increase in GSH in the lung tissue of VSC-treated rats. However, both WSC and VSC markedly reduced GSH in bronchoalveolar lavage (BAL) fluid. Reduction in lung GSH to 95% but not to 68% of control values by BSO increased lung epithelial permeability in vivo. However, there was no additive effect on epithelial permeability of WSC and BSO.(ABSTRACT TRUNCATED AT 250 WORDS)

Type-specific immune response to human T cell lymphotropic virus (HTLV) type I and type II infections in Nigeria

Type-specific antibody responses to human T cell lymphotropic virus type I (HTLV-I) and type II (HTLV-II) were studied in blood samples collected from 25 different locations in Nigeria between 1985 and 1991 and stored at the University College Hospital in Ibadan. A total of 4,153 sera were collected from participants in the National Immunity Survey of Viral Infections (n = 1,640), patients with tuberculosis (TB) (n = 140), patients with sexually transmitted diseases (STDs) (n = 876), patients with other medical conditions (n = 1,285), female prostitutes (n = 60), and health care workers (n = 152). The overall seroprevalence of HTLV was 5.6%, with similar rates among males and females. Using enzyme immunoassays that differentiated between antibodies to the two viruses, the seroprevalence rates were 2.5% for HTLV-I and 1.9% for HTLV-II, with an additional 1.2% of the samples dually reactive for both HTLV-I and HTLV-II. The seroprevalence rates for HTLV were low among children (0.8%) and adolescents (1.7%), with substantially higher rates among adults (range 5.0-7.4%). Age-specific patterns among adults appears to differ for HTLV-I and HTLV-II, with HTLV-I rates peaking above age 50 and HTLV-II rates peaking below age 50. The highest overall HTLV prevalence rates were observed for STD patients (16.3%), followed by female prostitutes (8.3%), TB patients (6.4%), health care workers (3.3%), patients with other medical conditions (3.2%), and immunity survey participants (1.8%).(ABSTRACT TRUNCATED AT 250 WORDS)

Mesothelial cell injury caused by pleural leukocytes from rats treated with intratracheal instillation of crocidolite asbestos or Corynebacterium parvum

The pleural and peritoneal mesothelium is a major target in asbestos exposure where mesothelial cell proliferation, exfoliation, and neoplasia have been reported in workers and experimental animals. The objective of this study was to determine the role of pleural leukocytes in mesothelial cell damage caused by asbestos exposure. We therefore investigated detachment and lysis injury to mesothelial cells in vitro induced by leukocytes lavaged from the pleural space of rats exposed, by intratracheal instillation, to crocidolite asbestos. Our studies revealed that normal pleural leukocytes were composed of macrophages, lymphocytes, eosinophils, and mast cells. This population showed a small but significant recruitment of mast cells and eosinophils 3 to 14 days after instillation of crocidolite asbestos; there were also modestly increased levels of macrophages present 30 days after low doses of asbestos. One day after intratracheal instillation of 5 mg crocidolite asbestos, the pleural leukocytes caused detachment injury to mesothelial cells in vitro. This injury was markedly reduced 3 days after asbestos exposure and was undetectable by Day 14. One month after instillation of asbestos, despite doses of asbestos from 0.5 to 5 mg, pleural leukocytes showed no ability to injure mesothelial cells in vitro. In a parallel study, pleural inflammation was induced by intratracheal instillation of heat-inactivated Corynebacterium parvum. Transient mesothelial cell-detaching injury was again expressed by pleural leukocytes 1 day after C. parvum instillation. This was likely related to an increase in the percentage of neutrophils present on this day. These results show that a single administration of crocidolite asbestos, intratracheally, leads to transient activation of pleural leukocytes in terms of the ability of these cells to detach mesothelial cells from matrix. This finding implies that mesothelial cell proliferation and exfoliation found in individuals exposed to asbestos may result from persistent stimulation of pleural leukocytes caused by the continuous presence of asbestos in the lung.

An improved method for the measurement of malondialdehyde in biological samples

An improved method was developed for measuring malondialdehyde (MDA) as its thiobarbituric acid (TBA) complex. Samples were initially incubated with 1% potassium iodide and 0.1% butylated hydroxytoluene at 50 degrees C for 20 min, and then with 0.4% TBA at 60 degrees C for 60 min. The MDA-TBA complex formed was extracted with isobutyl alcohol and measured by high-performance liquid chromatography with fluorescence detection. The improved method allows for a more specific determination of MDA present in biological samples.

Expression levels of IL-6 mRNA in PBMNCs from patients with IDDM, NIDDM and normals by RT-PCR procedure

Although it has been confirmed that insulin dependent diabetes mellitus (IDDM) is a kind of autoimmune disease, islet cell autoantibodies (ICAs), insulin autoantibodies (IAA) and anti-GAD-glutamic acid decardaxylase antibodies have been found in the sera of patients with IDDM and immunotherapies have been used in some patients with IDDM, yet the manner in which the dysfunctional immunosystem acts on beta cells and causes damage to them remains to be clarified. Recently, possible involvement of the abnormal production of IL-6 in autoimmune symptoms was suggested in patients with cardiac myxomas, Castleman's disease and rheumatoid arthritis. However reports of IL-6 abnormal production in patients with IDDM are rare. In the present study, we examined whether or not an abnormal expression of IL-6 mRNA was present in mononuclear cells (PBMNCs) of the peripheral blood of patients with IDDM. We devised a highly sensitive, specific and semiquantitative protocol, ie, reverse transcription and polymerase chain reaction (RT-PCR). We have used such an assay to measure the relative expression levels of IL-6 mRNA in PBMNCs from 12 early IDDM patients (duration < 6 mon, 8.20 +/- 3.85 yr), 29 newly-diagnosed NIDDM patients (54.85 +/- 9.12 yr), 23 normal children (8.20 +/- 3.26 yr) and 12 normal adults (31.92 +/- 11.22 yr). In this assay significantly high expression levels of IL-6 mRNA were found in PBMNCs from patients with IDDM (P < 0.05). The relative levels were 0.91 +/- 0.19; 0.10 +/- 0.06; 0.43 +/- 0.08; 0.10 +/- 0.07, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitumor activity and immuno-potentiating actions of Achyranthes bidentata polysaccharides

Achyranthes bidentata polysaccharides (ABP), isolated from the root of Achyranthes bidentata Blume, 50 mg.kg-1 ip or 250 mg.kg-1 to ICR mice inhibited the growth of sarcoma 180. ABP 50 and 100 mg.kg-1 ip prolongated the survival days of mice bearing Ehrlich carcinoma. ABP 50-800 micrograms.ml-1 did not exert direct cytotoxic effect in vitro on S180 cells, but enhanced the cytotoxicity of peritoneal macrophages against S180 cells. ABP 50 mg.kg-1 ip x 17 d or 250 mg.kg-1 ig x 16 d promoted the plaque forming cells (PFC) response to sheep red blood cells (SRBC) and serum IgG level as well as splenocyte proliferation induced by mitogen Con A or LPS in tumor-induced immunodeficient mice. ABP also elevated the NK cell activity and serum TNF content in mice bearing S180. These results indicated that the antitumor effect of ABP may be related to its potentiating effect on both specific and nonspecific host immunological responses.

Analyzing the red-shift characteristics of azulenic, naphthyl, other ring-fused and retinyl pigment analogs of bacteriorhodopsin

Prompted by the near infrared-absorbing properties of some of the azulenic bacteriorhodopsin (bR) analogs, we have analyzed their absorption characteristics along with 11 new related ring-fused analogs and the corresponding Schiff bases (SB) and protonated Schiff bases (PSB). The following three factors are believed to contribute to the total red shift of each of the pigment analogs (sigma RS): perturbation of the basic chromophore (SB shift, delta SB), protonation of the SB (PSB shift, PSBS) and protein perturbation (the opsin shift, OS). For each factor, effects of structural modifications were examined. For the red-shifted pigments, percent OS has been suggested as an alternate way of measuring protein perturbation. Computer-simulated chromophores provided evidence against any explanation involving altered shapes of the binding pocket as a major cause for absorption differences. Implications of the current bR results on preparation of further red-shifted bR and possible application to visual pigment analogs are discussed.

Direct evidence that the hydroxyl radical plays a pathogenetic role in myocardial "stunning" in the conscious dog and demonstration that stunning can be markedly attenuated without subsequent adverse effects

Recent studies suggest that the hydroxyl radical (.OH) plays a pathogenetic role in postischemic ventricular dysfunction (myocardial "stunning"). This concept, however, is predicated exclusively on results obtained in anesthetized open-chest preparations, which are subject to the confounding influence of many unphysiological conditions and in which both myocardial stunning and free radical generation are greatly exaggerated. The lack of supporting evidence in more physiological animal models represents a major limitation of the .OH hypothesis of stunning. Furthermore, concern has been raised that myocardial stunning may be a period of "rest" necessary for full recovery, so that attenuation of the early phase of stunning by antioxidant therapy may have subsequent detrimental effects on the resting function and/or on the return of myocardial contractile reserve. To address these issues, in phase 1 of this study conscious unsedated dogs undergoing a 15-minute coronary artery occlusion received an intravenous infusion of normal saline (n = 22), of the .OH scavenger N-2-mercaptopropionyl glycine (MPG, n = 17), or of the iron chelator desferrioxamine (DF, n = 14). Compared with control dogs, the dogs treated with MPG or DF exhibited significantly greater postischemic wall thickening throughout the first 6 hours of reperfusion; the total deficit of wall thickening during this time interval was reduced 50% by MPG and 50% by DF. The magnitude of this beneficial effect was a function of the severity of ischemia, so that the dogs with the lowest collateral flows had the greatest improvement of wall thickening. The accelerated recovery produced by MPG and DF in the first 6 hours was not followed by any deterioration of resting wall thickening at 24 or 48 hours. Furthermore, in dogs treated with MPG or DF, the increase in wall thickening elicited by maximal inotropic stimulation (isoproterenol or dopamine) was similar before stunning and shortly after resting wall thickening had normalized (24 or 48 hours after reflow); thus, despite the fact that most of the early postischemic dysfunction had been eliminated by antioxidant therapy, there was no subsequent impairment of either resting function or contractile reserve. In phase 2, production of free radicals (measured with the spin trap alpha-phenyl N-tert-butyl nitrone) was markedly (> 80%) inhibited by the same doses of MPG and DF that attenuated stunning in phase 1.(ABSTRACT TRUNCATED AT 400 WORDS)

Lymphocytes protect against and are not required for reovirus-induced myocarditis

Many studies suggest that host lymphocytes are damaging, rather than protective, in virally induced myocarditis. We have investigated the role of lymphocyte-based immunity in murine myocarditis by using a myocarditic reovirus (reovirus serotype 3 8B), nonmyocarditic reoviruses, adoptive transfer experiments, and mice with severe combined immunodeficiency (SCID mice). Prior to infection, passive transfer of monoclonal antibodies specific for 8B capsid proteins protected neonatal mice against 8B-induced myocarditis, indicating that humoral immunity can protect against myocarditis. Some monoclonal antibodies acted by blocking viral spread to and/or replication in the heart. Passive transfer of reovirus-immune, but not naive, spleen cells prior to infection protected neonatal mice from 8B-induced myocarditis. Depletion of either CD4 or CD8 T cells resulted in increased viral titer in the heart but did not abrogate immune cell-mediated protection against myocardial injury. This shows that both CD4 and CD8 T cells can act independently to protect myocardial tissue from reovirus infection. In addition, reovirus 8B caused extensive myocarditis in SCID mice. This confirms a prior report (B. Sherry, F. J. Schoen, E. Wenske, and B. N. Fields, J. Virol. 63:4840-4849, 1989) that T cells are not required for reovirus-induced myocarditis and demonstrates for the first time that B cells are not required for reovirus-induced myocarditis. We used SCID mice and a panel of reoviruses to assess (i) the relationship between growth in the heart and myocardial damage and (ii) the possibility that nonmyocarditic reoviruses exhibit a myocarditic phenotype in the absence of functional lymphocytes. Growth in the heart was not the sole determinant of myocarditic potential in SCID mice. Although 8B induced myocarditis in SCID mice, no or minimal myocarditis was found in SCID mice infected with four reovirus strains previously shown (B. Sherry and B. N. Fields, J. Virol. 63:4850-4856, 1989) to be nonmyocarditic or poorly myocarditic in normal neonatal mice. We conclude that (i) humoral immunity and cellular immunity are protective against, and not required for, reovirus-induced myocarditis and (ii) the potential to induce cardiac damage is a property of the virus independent of lymphocyte-based immunity.

Use of aromatic hydroxylation of phenylalanine to measure production of hydroxyl radicals after myocardial ischemia in vivo. Direct evidence for a pathogenetic role of the hydroxyl radical in myocardial stunning

A pathogenetic role of .OH in myocardial stunning has been inferred from the protective effects of .OH scavengers and iron chelators. However, conclusive demonstration of the .OH radical hypothesis of myocardial stunning requires direct verification of three major, but still unproven, assumptions: (1) .OH is produced in the stunned myocardium in vivo; (2) antioxidant therapy inhibits .OH production; and (3) such inhibition results in enhanced recovery of contractility (ie, .OH is necessary for the development of myocardial stunning). Since phenylalanine (Phe) reacts with .OH to form the hydroxylated products ortho-, meta-, and para-tyrosines (o-, m-, and p-tyr), we used aromatic hydroxylation of Phe to detect .OH formation in the stunned myocardium. Open-chest dogs undergoing a 15-minute coronary occlusion followed by reperfusion received an intravenous infusion of Phe (54.3 mg/kg for 11.5 minutes beginning 90 seconds before reperfusion); these animals were given either no antioxidant therapy (group I, n = 15), N-2-mercaptopropionyl glycine (MPG) (group II, n = 11), or MPG combined with superoxide dismutase, catalase, and desferrioxamine (group III, n = 12). In addition, group IV (nonischemic control group, n = 6) received Phe but did not undergo coronary occlusion, whereas group V (ischemic control group, n = 16) underwent a 15-minute occlusion but did not receive Phe or antioxidants. The plasma concentrations of tyrosines in the local venous effluent and in the arterial blood were measured with high-performance liquid chromatography. In group I, production of o- and m-tyr, which are specific markers of .OH formation, began during coronary occlusion but increased dramatically immediately after reperfusion, peaking at 1 minute and continuing up to 10 minutes of reperfusion. In group II, the production of o- and m-tyr was markedly decreased throughout the first 10 minutes of reperfusion. In group III, the production of m-tyr was decreased to levels similar to those in group II, whereas the production of o-tyr was almost completely abolished. There was no appreciable production of o- or m-tyr in group IV. Recovery of contractile function (assessed as systolic wall thickening) was increased in group I vs group V. Recovery of function was further enhanced in group II, with only a slight additional improvement in group III.(ABSTRACT TRUNCATED AT 400 WORDS)

The production of TNF-alpha and IL-1-like activity by bronchoalveolar leucocytes after intratracheal instillation of crocidolite asbestos

We have used a rat intratracheal instillation model to study the effect of crocidolite asbestos exposure on cytokine production by bronchoalveolar lavage (BAL) leucocytes. In unexposed controls, the normal BAL leucocytes were mostly macrophages which spontaneously produced interleukin 1 (IL-1)-like activity and tumour necrosis factor (TNF-alpha) in culture; these levels were enhanced by stimulation with LPS. In animals exposed to crocidolite asbestos, two new types of cell, neutrophils and eosinophils, were recruited into the bronchoalveolar space by 1-3 days after instillation. However, the BAL profile had returned to normal by 14 days. The production of IL-1-like activity was decreased considerably compared to control from 1 to 14 days after asbestos instillation, but was increased at 30 days. However, the leucocytes produced increased TNF-alpha as early as 3 days after asbestos instillation and maintained this elevated level throughout the experimental period. Crocidolite asbestos in vitro also stimulated normal BAL leucocytes to release significantly increased amounts of IL-1-like activity and TNF-alpha. We conclude that the deposition of crocidolite asbestos fibre in the lung by instillation causes reduced production of IL-1-like activity in the acute phase, but elevated production of both IL-1-like activity and TNF in the chronic phase, suggesting that enhanced activities of these cytokines may contribute to the development of lung pathological changes in the long term.

Demonstration of free radical generation in the "stunned" myocardium in the conscious dog and identification of major differences between conscious and open-chest dogs

Conscious dogs undergoing a 15-min coronary occlusion were given alpha-phenyl N-tert-butyl nitrone (PBN) and the local coronary venous plasma was analyzed by electron paramagnetic resonance spectroscopy. A prolonged myocardial release of PBN radical adducts was observed, which exhibited a burst in the initial minutes of reflow (peaking at 3 min) and then abated but continued for 1-3 h after reperfusion. Computer simulation revealed the presence of at least two PBN adducts (aN = 15.2 G and a beta H = 6.0 G; aN = 14.6 G and a beta H = 3.0 G), both consistent with the trapping of secondary carbon-centered radicals. No appreciable PBN adduct production was observed when collateral flow exceeded 30-40% of nonischemic flow, indicating that a flow reduction of at least 60% is necessary to trigger free radical reactions. There was a direct relationship between the magnitude of PBN adduct production and the severity of contractile dysfunction (r = 0.77), suggesting that the radicals generated upon reperfusion play a causal role in the subsequent stunning. The total release of PBN adducts after 3 h of reperfusion following a 15-min coronary occlusion was found to be approximately five times greater in open-chest compared with conscious dogs; at the same time, the recovery of wall thickening was markedly less in open-chest dogs. This study represents the first application of spin trapping to a conscious animal model of myocardial ischemia. The results demonstrate (a) that free radicals are generated in the stunned myocardium in the absence of the artificial or abnormal conditions associated with previously used models (isolated hearts, open-chest preparations), and (b) that both the severity of postischemic dysfunction and the magnitude of the attendant free radical production are greatly exaggerated in the open-chest dog, implying that previous conclusions derived from this model may not be applicable to conscious animals or to humans. This investigation also provides a method to measure free radicals in awake animals.

Effects of Achyranthes bidentata polysaccharides on interleukin-1 and tumor necrosis factor-alpha production from mouse peritoneal macrophages

Achyranthes bidentata polysaccharides (ABP), extracted from the root of Achyranthes bidentata, induced interleukin-1 (IL-1) synthesis as well as tumor necrosis factor-alpha (TNF-alpha) synthesis and secretion from thioglycolate-primed mouse peritoneal macrophages in vitro. ABP 100-800 micrograms.ml-1 enhanced both synthesis and release of IL-1 when stimulated by lipopolysaccharides (LPS) (5 micrograms.ml-1), but had no significant influences on synthesis and release of TNF-alpha induced by LPS (10 micrograms.ml-1). Studies on IL-1 and TNF-alpha production induced by ABP (200 micrograms.ml-1) alone or plus LPS showed that peak levels of IL-1 release reached at 24 h and that of TNF-alpha release at about 2-6 h after incubation. Peritoneal macrophages from mice ip ABP 25 and 50 mg.kg-1.d-1 x 5 d produced much more IL-1 than those from control group. Peritoneal macrophages from ip ABP 100 mg.kg-1.d-1 x 6 d alone released more TNF-alpha vs control group, and showed a synergetic action with LPS (10 micrograms.ml-1), which was as strong as the positive control agent BCG. These results provide an explanation for the immunopotentiating effect of ABP.

Study of activation of murine T cells with bacterial superantigens. In vitro induction of enhanced responses in CD4+ T cells and of anergy in CD8+ T cells

Primary and secondary responses of murine CD4+ T cells and CD8+ T cells upon stimulation with staphylococcal enterotoxin E (SEE) bearing superantigenic properties were examined. Both isolated C57BL/6 splenic CD4+ T cells and CD8+ T cells proliferated and produced IL-2 and IFN-gamma upon stimulation with SEE in substantial levels. The amounts of IL-2 were greater in CD4+ T cells and those of IFN-gamma were somewhat greater in CD8+ T cells. SEE-induced CD4+ T lymphoblasts, larger parts of which bore the V beta 11 element in their TCR, proliferated, produced IL-2 and IFN-gamma, and showed toxin-dependent cytotoxicity in substantial levels upon restimulation with SEE. By contrast, SEE-induced CD8+ T lymphoblasts, the larger part of which bore the V beta 11 element, did not show the first two of the three responses at all upon restimulation with SEE, whereas these cells showed greater cytotoxicity. The CD8+ T lymphoblasts did not suppress the reactivity of the CD4+ T lymphoblasts. Both SEE-induced CD4+ T lymphoblasts and CD8+ T lymphoblasts proliferated and produced IL-2 and IFN-gamma in comparable levels upon stimulation with rIL-2 or mAb to CD3 or V beta 11.

Study of activation of murine T cells with bacterial superantigens. In vitro induction of enhanced responses in CD4+ T cells and of anergy in CD8+ T cells

Primary and secondary responses of murine CD4+ T cells and CD8+ T cells upon stimulation with staphylococcal enterotoxin E (SEE) bearing superantigenic properties were examined. Both isolated C57BL/6 splenic CD4+ T cells and CD8+ T cells proliferated and produced IL-2 and IFN-gamma upon stimulation with SEE in substantial levels. The amounts of IL-2 were greater in CD4+ T cells and those of IFN-gamma were somewhat greater in CD8+ T cells. SEE-induced CD4+ T lymphoblasts, larger parts of which bore the V beta 11 element in their TCR, proliferated, produced IL-2 and IFN-gamma, and showed toxin-dependent cytotoxicity in substantial levels upon restimulation with SEE. By contrast, SEE-induced CD8+ T lymphoblasts, the larger part of which bore the V beta 11 element, did not show the first two of the three responses at all upon restimulation with SEE, whereas these cells showed greater cytotoxicity. The CD8+ T lymphoblasts did not suppress the reactivity of the CD4+ T lymphoblasts. Both SEE-induced CD4+ T lymphoblasts and CD8+ T lymphoblasts proliferated and produced IL-2 and IFN-gamma in comparable levels upon stimulation with rIL-2 or mAb to CD3 or V beta 11.

Effect of transforming growth factor-beta 1 on myocardial stunning in the intact dog

Previous studies have demonstrated that transforming growth factor-beta (TGF-beta) can accelerate wound healing, inhibit free radical formation and limit myocardial ischemia/reperfusion injury in a variety of experimental models. However, it is unknown whether exogenous TGF-beta 1 can attenuate the prolonged contractile dysfunction that is observed after a brief, reversible ischemic insult (myocardial stunning). Thus, open-chest dogs undergoing a 15-min left anterior descending coronary artery occlusion and 4 h of reperfusion were given TGF-beta 1 as an intravenous bolus (250 micrograms) at 24 h and again at 1 h before coronary occlusion (n = 5). Control dogs (n = 7) received equivalent amounts of vehicle. The two groups were similar with respect to occluded bed size, collateral blood flow and rate-pressure product. Fundamental physiological parameters, such as body temperature, arterial pH, PO2 and hematocrit, were within normal limits throughout the experiment. In control dogs, regional myocardial function (assessed as systolic thickening fraction) remained depressed throughout the 4 h reperfusion period, indicating severe myocardial stunning. TGF-beta 1 did not produce any significant improvement in the recovery of regional function; 4 h after reperfusion, paradoxical systolic thinning was still present in both treated and control groups, with thickening fraction being -22.5 +/- 6.1% and -31.0 +/- 5.3% of baseline, respectively (P = N.S.). These results demonstrate that a large dose of TGF-beta 1 given before ischemia fails to attenuate myocardial stunning in the open-chest dog, suggesting that this growth factor does not exert protective effects in the setting of reversible myocardial ischemia/reperfusion injury.

Effects of the spin trap alpha-phenyl N-tert-butyl nitrone on myocardial function and flow: a dose-response study in the open-chest dog and in the isolated rat heart

Alpha-phenyl N-tert-butyl nitrone (PBN) is widely used in spin-trapping experiments, but its possible toxicity has not been systematically evaluated. The purpose of this study was to investigate the effects of different doses of PBN on cardiac function in vivo (open-chest dogs) and in vitro (isolated rat hearts). In open-chest dogs, PBN was infused intracoronarily to achieve coronary arterial concentrations ranging from 1.6 mM to 10.0 mM. At coronary arterial concentrations of 1.6 mM and 2.5 mM, PBN had no appreciable effect on regional myocardial function (assessed as systolic wall thickening). However, coronary arterial concentrations of PBN of 5.0 mM and 10.0 mM produced a marked reduction and, eventually, a complete loss of systolic wall thickening (53% of baseline values after 30 min at 5.0 mM and 14% after 30 min at 10.0 mM). Furthermore, PBN increased coronary blood flow by approximately 25% at 2.5 mM and by > 100% at 10.0 mM. In isolated rat hearts, perfusion with 2.5 and 5.0 mM PBN for 60 min did not significantly affect global myocardial function, assessed as developed pressure, rate-pressure product, and positive and negative dP/dt. At the 10.0 mM concentration, however, these variables were significantly decreased after 30 min (developed pressure: -77% vs. controls; rate-pressure product: -84%; +dP/dt: -60%; -dP/dt: -70%); two out of five hearts stopped beating within 30 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of human immunodeficiency virus types 1 and 2 infections in Nigeria

The prevalence of human immunodeficiency virus (HIV) types 1 and 2 infections in Nigeria was estimated from 3854 serum samples collected at 21 locations from 1985 to 1990. Seventy-eight samples (2.0%) were reactive for HIV-1 and 49 (1.3%) for HIV-2 antibodies; 5 samples were reactive for both viruses. The prevalence of HIV-1 and -2 infections, respectively, was highest among 60 female prostitutes, with 10% and 6.7% positive. For other groups the respective rates of positivity were 4.1% and 3.4% in 610 patients with sexually transmitted diseases, 3.6% and 1.4% in 140 tuberculosis patients, 1.6% and 0.6% of 1253 other medical patients, and 1.2% and 0.9% of 1640 volunteer blood donors. Of 153 health care workers, 1.3% were positive for HIV-1 only. The age group from 20 to 29 years had the highest prevalences of HIV-1 (3.3%) and -2 (2.2%). In Nigeria, antibody prevalence for both viruses appears to have increased > 10-fold between 1986 and 1990.

Determination of 3-methylflavone-8-carboxylic acid, the main metabolite of flavoxate, in human urine by capillary electrophoresis with direct injection

The effects of tetraalkylammonium salts and sodium dodecyl sulphate on the migration behaviour of human urinary components and other negatively charged or neutral solutes were investigated. The sulphate acted mainly on hydrophobic and positively charged substances, whereas the ammonium salts acted mainly on negatively charged solutes. By choosing the components of the eluent carefully, the free and conjugate forms of 3-methylflavone-8-carboxylic acid (MFA) in human urine, the major metabolites of flavoxate, could be simultaneously determined without pretreatment, using fenprofen as an internal standard. The calibration curve of MFA was linear in the range 1-50 micrograms/ml and the detection limit was 0.2 microgram/ml, which covered the urine levels encountered in pharmacokinetic studies. The intra-day and inter-day precisions of the method, expressed as the relative standard deviation, were less than 2 and 3%, respectively. This method was successfully applied to an excretion study of MFA in eight healthy volunteers, and the results were in agreement with data in the literature obtained by gas chromatography.

Reactive pleural inflammation caused by intratracheal instillation of killed microbes

To investigate the pleural leucocyte response to severe alveolar inflammation, heat-killed Corynebacterium parvum were instilled intratracheally into the lungs of PVG rats and pleural lavage was performed. Polymorphonuclear neutrophils are not normally resident in the pleural space but were found transiently after intratracheal instillation of C. parvum. Macrophages increased gradually in the pleural space following instillation, reaching a peak at day 5. The activity of plasminogen activator inhibitor in the pleural leucocyte supernatants was increased at day 1, but returned to control levels by day 5. The activities of interleukin-1 and tumour necrosis factor secreted by pleural leucocytes were decreased compared with control pleural leucocytes at day 1 and were further reduced at day 5. The analysis of particle translocation showed that intratracheally instilled C. parvum and fluorescent beads with or without C. parvum did not reach the pleural space. We hypothesize that pleural inflammation resulting from C. parvum-induced inflammation in the lung is the result of transfer of a diffusible factor from the adjacent parenchyma.

Reactive pleural inflammation caused by intratracheal instillation of killed microbes

To investigate the pleural leucocyte response to severe alveolar inflammation, heat-killed Corynebacterium parvum were instilled intratracheally into the lungs of PVG rats and pleural lavage was performed. Polymorphonuclear neutrophils are not normally resident in the pleural space but were found transiently after intratracheal instillation of C. parvum. Macrophages increased gradually in the pleural space following instillation, reaching a peak at day 5. The activity of plasminogen activator inhibitor in the pleural leucocyte supernatants was increased at day 1, but returned to control levels by day 5. The activities of interleukin-1 and tumour necrosis factor secreted by pleural leucocytes were decreased compared with control pleural leucocytes at day 1 and were further reduced at day 5. The analysis of particle translocation showed that intratracheally instilled C. parvum and fluorescent beads with or without C. parvum did not reach the pleural space. We hypothesize that pleural inflammation resulting from C. parvum-induced inflammation in the lung is the result of transfer of a diffusible factor from the adjacent parenchyma.

Production of interleukin 1 by rat pleural leucocytes in culture after intratracheal instillation of crocidolite asbestos

This study was undertaken to investigate the production of interleukin 1 (IL-1) by pleural leucocytes in culture and to evaluate the influence of intratracheal instillation of crocidolite asbestos on this production. Normal pleural leucocytes spontaneously released IL-1 in culture and stimulation with lipopolysaccharide (LPS) dramatically increased production. Intratracheal instillation with crocidolite asbestos induced recruitment of pleural leucocytes in the longer term and changed IL-1 production by the leucocytes. Reduced production of IL-1 was found by one day after instillation of asbestos and this was correlated with the dose of asbestos. With increasing time after instillation, however, release of IL-1 by pleural leucocytes gradually recovered to normal until, one month after asbestos injection, the leucocytes produced augmented IL-1 in culture compared with control pleural leucocytes. Our data show that pleural leucocytes possess the potential to produce IL-1 in vitro and this capability is altered by intratracheal instillation of crocidolite asbestos. This may be relevant to development of pleural diseases associated with inhalation of asbestos.

T cells expressing both L-selectin and CD44 molecules increase in number in peritoneal exudate cells and in vitro-stimulated spleen cells from mice immunized intraperitoneally with Listeria monocytogenes

L-selectin, which was first reported as MEL-14 antigen in mice, is a type of animal lectin and expressed on lymphocytes, neutrophils and macrophages. L-selectin has been reported to be a homing receptor of lymphocytes to peripheral lymph nodes and to have an important role in initial adhesion of lymphocytes and neutrophils to endothelial cells activated by inflammatory cytokines. On the other hand, it has been reported that naive T cells express L-selectin while memory T cells and in vitro antigen-stimulated T cells lose its expression. If all memory T cells lack L-selectin, trafficking of memory T cells into inflammatory sites would be difficult. To know whether all memory T cells lack L-selectin expression, kinetics of expression of L-selectin was analysed on memory T-cell subsets, which are detected by expression of CD44, in mice after intraperitoneal immunization with a sublethal dose of viable Listeria monocytogenes. T cells expressing both L-selectin and CD44 were detected in splenocytes and peritoneal exudate cells (PEC) from untreated mice, though at low levels. L-selectin+ CD44+ T cells increased in PEC, which are known to be highly enriched in antigen-primed T cells, and reached maximum level on day 14 after immunization. Furthermore, we found increases not only of L-selectin- CD44+ but also of L-selectin+ CD44+ T cells by in vitro Listeria antigen stimulation of Listeria-immune spleen cells on day 14. These results showed that T cells expressing both L-selectin and CD44 increase after antigen stimulation in vivo and in vitro. The L-selectin+ CD44+ T cells may be a subset of memory T cells which retain their capacity of trafficking to inflammatory sites.

Asbestos-stimulated tumour necrosis factor release from alveolar macrophages depends on fibre length and opsonization

Fibre length has been shown to be an important factor in the ability of respirable fibres to cause lung fibrosis and cancer. We have reported that a long sample of amosite asbestos is more carcinogenic and fibrogenic than a short sample of similar diameter. These amosite asbestos samples were studied with regard to their ability to stimulate the release of the pro-inflammatory cytokine tumour necrosis factor (TNF) from rat alveolar macrophages in vitro. The long fibre sample was found to stimulate substantially greater release of the cytokine than the short sample. Furthermore, on treatment of the fibres with rat immunoglobulin G (IgG), there was an increase in the ability of both the long and the short sample to stimulate TNF secretion, although the long sample retained by far the greatest activity. Coating of the fibres with a range of other proteins had no substantial effect on their ability to stimulate TNF secretion. Quartz and titanium dioxide (TiO2) were included as control particles and the TNF-stimulating activity of quartz was notably increased by opsonization with IgG. TiO2 showed a similar low activity to that of the short fibre sample of amosite but this again could be modestly increased by opsonization with IgG. The simulation of TNF release caused by treatment with immunoglobulin-opsonized long fibre amosite could be inhibited by treatment of the macrophages with the protein kinase C-inhibitor staurosporine. The study demonstrates a fibre length-related ability to stimulate cytokine secretion by alveolar macrophages, and its enhancement by opsonization with IgG.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal antibodies to NF-Y define its function in MHC class II and albumin gene transcription

NF-Y is a sequence-specific DNA-binding protein which, as a heterodimer, recognizes CCAAT motifs in a variety of transcriptional promoters. We have generated a panel of monoclonal and affinity-purified polyclonal antibodies directed against various epitopes of NF-Y. These reagents are highly specific for either of the A or B subunits; we have mapped the epitopes recognized by the monoclonal antibodies to the glutamine-rich activation domain of NF-YA. The antibodies inhibit in vitro transcription from the promoters of the albumin gene and of Ea, a class II gene of the major histocompatibility complex. These data definitively demonstrate the role of NF-Y in regulating the transcription of two tissue-specific genes whose expression patterns do not overlap. Interestingly, the antibodies cannot inhibit a formed pre-initiation complex, but do block reinitiation of subsequent rounds of transcription from the same templates.

Intron-exon organization of the NF-Y genes. Tissue-specific splicing modifies an activation domain

NF-Y is a highly conserved transcription factor which recognizes CCAAT motifs in a variety of genes. We report here the genomic organization of the genes encoding both subunits, which gives interesting clues about the functional organization of the proteins. We also report the existence of isoforms of NF-YA which result from differential splicing. These alternative splicing events map within a glutamine-rich activation domain and show a marked cell- and tissue-specific bias.

Spectroscopic studies on the interaction of calf lens membranes with crystallins

The interaction of crystallins with lens membranes and liposomes was studied by fluorescence and circular dichroism (CD) measurements. Two extrinsic fluorescence probes ANS (1-anilino-naphthalene-8-sulfonic acid) and DPH (1,6-diphenyl, 1,3,5-hexatriene) were used to detect the binding and to explore the binding site. The ANS fluorescence intensity is greater in membranes than in liposomes, but is reverse for DPH. Among alpha, beta and gamma-crystallins, only alpha c-crystallin decreased the ANS fluorescence intensity in membranes, indicating a binding between membranes and alpha c-crystallin. The binding site appears to be at the polar-apolar interface in membrane protein (MIP26) and alpha c-crystallin. Fluorescence polarization measurements show that lipid bilayer becomes less mobile with alpha c-crystallin binding. The change in the near UV CD due to the binding also indicates a decreased freedom of rotation of aromatic amino acid residues either in MIP26 or in alpha-crystallin.

Intratracheal injection of crocidolite asbestos depresses the secretion of tumor necrosis factor by pleural leukocytes in vitro

Tumor necrosis factor (TNF) is a cytokine released predominantly by monocytes/macrophages that has been shown to modulate a variety of different immune and metabolic functions. To understand the regulatory mechanisms of TNF in governing responses in the pleural cavity following deposition of fibrous dust in the airspace of the lung, we studied the capability of leukocytes, lavaged from the pleural cavity, to release TNF in culture. TNF production by lavaged pleural leukocytes was measured using the L-929 TNF-sensitive cell line, after intratracheal instillation of crocidolite asbestos. A high level of TNF activity was found in the supernatants of normal, unstimulated pleural leukocytes; the addition of 100 ng/ml lipopolysaccharide to the culture increased the activity up to threefold. Following intratracheal instillation of 5 mg crocidolite asbestos, the pleural leukocytes secreted less TNF than the control. With increasing mass of intratracheally instilled asbestos, there was a dose-dependent reduction in TNF release. Changes in the population of the pleural leukocytes or their number could not be related to variation in TNF activity. These results suggest that exposure of rat lungs to crocidolite asbestos by intratracheal instillation affects the response of pleural leukocytes without causing changes in the population. Such changes in the bronchoalveolar space may be related to the pleural pathology found in asbestos-exposed individuals.

Evolutionary variation of the CCAAT-binding transcription factor NF-Y

NF-Y is a CCAAT-specific transcription factor thought to be involved in the regulation of a variety of eukaryotic genes. It shows a striking sequence similarity with the yeast factor HAP2/3. In an attempt to trace back its evolutionary history, we succeeded in isolating NF-Y cDNA clones from a plant and from several species of vertebrates. The patterns of sequence conservation delineate potential functional domains: A central, highly conserved, domain likely responsible for DNA-binding and subunit interaction; more evolutionarily flexible flanking regions, in which variability is clustered, individualizing conserved glutamine or acidic amino-acids putatively involved in protein-protein contacts.

Influence of methionine-enkephalin on interleukin-2 production and interleukin-2 receptor expression

Influences of methionine enkephalin (met-enk) on delayed hypersensitivity (DH) against 2,4-dinitrofluoro-benzene (DNFB) and interleukin-2 (IL-2) production of mouse lymphocytes were examined. Met-enk enhanced the DH response to ear challenge when mice were treated with met-enk beginning at the same time as cpicutaneous sensitization with DNFB but not after being sensitized. When met-enk (10 nmol.L-1-100 mumol.L-1) was included in Con A-stimulated lymphocyte cultures, the IL-2 production increased in a concentration-dependent manner. Furthermore, in vivo treatment with met-enk also increased IL-2 production of splenocytes, and the enhancement of IL-2 production was parallel to that of lymphocyte proliferation. However, met-enk 10 nmol.L-1 had no effect on IL-2 receptor expression on thymocytes, splenocytes, and gut-associated lymphocytes. The data suggested that the stimulative effect of met-enk on lymphocytes may be mediated through the increase of IL-2, but not through the IL-2 receptor expression.

C-FOS EXPRESSION DURING ELECTROACUPUNCTURE ANALGESIA IN RATS - AN IMMUNOHISTOCHEMICAL STUDY

Although the central mechanisms of electroacupuncture analgesia (EAA) have been investigated, a systematic study for the involvement of neuronal populations of central nervous system (CNS) in EAA has not been well undertaken, largely due to the difficulty in tracing the neuronal pathways by traditional techniques. Recently developed c-fos expression examination by immunohistochemical method with Ab-1 antisera might be used for this purpose as a useful marker for neuronal activity in CNS. In this study, tail flick latency (TFL) was tested as an index of pain threshold in conscious rats. After unilateral electroacupuncture was applied at 'Zuan-san-li' and 'Huan-tiao', the TFL was significantly prolonged. To explore the possible involvement of certain neuronal groups of central nervous system in EAA, we examined the EAA accompanied c-fos expression throughout the neuraxis, and a lot of specific c-fos protein labelled neurons were found in lumbar spinal cord (laminae I and II), nucleus raphe magnus, nucleus raphe dorsalis, substantia grisea centralis, nucleus habenulae lateralis, nucleus habenulae medialis, nucleus medialis thalami, nucleus lateralis hypothalami, nucleus supramamillaris, nucleus supraopticus, nucleus arcuatus, nucleus preopticus medialis, nucleus amygdala, nucleus tractus diagonalis, etc. No obvious c-fos expression was shown in these areas on control rats. These results strongly suggested that the functional activation of above-mentioned nuclei by electroacupuncture was underlied in EAA action.

Effect of a traditional Chinese medicine, bu-zhong-yi-qi-tang (Japanese name: Hochu-ekki-to) on the protection against Listeria monocytogenes infection in mice

Effects of Bu-Zhong-Yi-Qi-Tang (Japanese name: Hochu-ekki-to) on the resistance against Listeria monocytogenes were observed in ICR mice orally administered this medicine daily for 10 days. Survival rates were increased by the pretreatment in mice inoculated i.v. with bacteria 1 day after the last administration and in mice inoculated i.p. 4 days after the last administration. After an i.v. inoculation of L. monocytogenes, the numbers of bacteria in the spleen and liver increased gradually to kill mice by day 5 in untreated group but the bacterial numbers increased slightly by day 3 and decreased from day 3 to day 8 in Hochu-ekki-to pretreated group. After an i.p. inoculation, the number of bacteria in the peritoneal cavity decreased very rapidly within 6h in Hochu-ekki-to treated group compared to that in untreated group. After the administration, number of polymorphonuclear cells increased in the peripheral blood, peritoneal cavity and spleen. In treated mice, macrophages increased in number in the peritoneal cavity and the spleen but decreased in the peripheral blood. Peritoneal macrophages from treated mice showed an enhanced activity to kill L. monocytogenes in vitro within 60 min after ingestion of bacteria. Hochu-ekki-to may augment the host defense against L. monocytogenes through the activation of macrophage series during an early phase of infection.

One subunit of the transcription factor NF-Y maps close to the major histocompatibility complex in murine and human chromosomes

The genes coding for the A and B subunits of the transcription factor NF-Y are assigned by a combination of in situ hybridization and analysis of somatic cell hybrids and recombinant mouse strains. NF-YA is assigned to human chromosome 6p21 and to mouse chromosome 17. NF-YB is assigned to human chromosome 12 and to mouse chromosome 10.

Butyl conformational reorganization as a possible explanation for the longitudinal flexibility of the binding site of bacteriorhodopsin. The azulene and C-22 retinoid analogs

The UV-VIS absorption data of four bacteriorhodopsin (BR) analogs formed from azulene-retinals of varying polyene chain length show that the one-bond-shortened to one-bond-lengthened analogs possess comparable opsin shift values to that of BR. A two-bond-shortened analog exhibited a much smaller opsin shift. These data, combined with those reported for the C-22 retinal analog (Tokunaga et al., 1977, Biophys. J. 19, 191-198) were analyzed by molecular modelling and computer graphics in terms of a model where conformational flexibility of the appended butyl is the controlling factor in determining ease of pigment formation and protein/substrate interaction.

Postischemic myocardial "stunning". Identification of major differences between the open-chest and the conscious dog and evaluation of the oxygen radical hypothesis in the conscious dog

Recent studies suggest that oxygen-derived free radicals contribute to the pathogenesis of postischemic myocardial dysfunction (myocardial "stunning"). This concept, however, is predicated exclusively on results obtained in open-chest preparations, which are subject to the confounding influence of many unphysiological conditions. The lack of supporting evidence in more physiological animal models represents a major persisting limitation of the oxy-radical hypothesis of myocardial stunning. The goal of this study was to address two fundamental (and related) questions: 1) Does the open-chest animal model alter the phenomenon of myocardial stunning? 2) If so, how valid are the concepts, derived from such a model, regarding the pathogenetic role of oxy-radicals? In part 1 of the study, myocardial stunning after a 15-minute coronary occlusion was compared in 30 pentobarbital-anesthetized open-chest dogs and in 19 conscious dogs. For any given level of collateral flow during occlusion, the recovery of systolic wall thickening after reperfusion was markedly less in open-chest animals. In an additional group of five open-chest dogs, a close inverse relation was noted between body temperature and postischemic wall thickening, indicating that the recovery of the stunned myocardium in acute experiments may vary markedly depending on how temperature is controlled. Because of these major differences between open-chest and conscious dogs, the oxy-radical hypothesis needs to be tested in the latter model. Thus, in part 2 of the study, conscious unsedated dogs undergoing a 15-minute coronary occlusion were randomized to an intravenous infusion of either saline (19 coronary occlusions) or superoxide dismutase (SOD) plus catalase (CAT) (21 coronary occlusions). Despite the fact that the plasma levels of SOD and CAT declined rapidly after reperfusion, postischemic wall thickening was significantly greater in treated compared with control dogs throughout the first 6 hours of reflow. Thus, a brief (60-minute) infusion of SOD and CAT produced a sustained improvement of recovery of contractility. The magnitude of this beneficial effect was a function of the severity of ischemia: the lower the collateral perfusion, the greater the improvement effected by the enzymes. The accelerated recovery produced by SOD and CAT was not followed by any deterioration of contractility, suggesting that postischemic dysfunction is not a teleologically "protective" phenomenon. In conclusion, the severity of myocardial stunning is greatly exaggerated by the unphysiological conditions present in the barbiturate-anesthetized open-chest dog.(ABSTRACT TRUNCATED AT 400 WORDS)

Interaction and aggregation of lens crystallins

Crystallins of the normal eye lens have a specific structure that maintains lens transparency. This structure reportedly arises from a short-range order. The age-related post-translational changes and high molecular weight (HMW) aggregation disrupt the normal structure and decrease lens transparency. In the current study, we have carried out fluorescence measurements (polarization and extrinsic probe binding) in an attempt to understand protein interaction and aggregation. Based on polarization measurements of dansyl chloride (DCl) labeled gamma-crystallin, there is a hetero-interaction among crystallins (alpha-gamma, beta-gamma, etc.) but no self-interaction in gamma-crystallin (gamma-gamma) (less than 30 mg ml-1). Alpha-crystallin is rich in hydrophobic region and possibly has a self-interaction through hydrophobic interaction. Hydrophobic probes, ANS (1-anilinonaphthalene-8-sulfonic acid) and DPH (1,6-diphenyl 1,3,5-hexatriene) measurements show that alpha-crystallin is a very hydrophobic protein. HMW alpha-crystallin appears to be even more hydrophobic, indicating that the post-translational unfolding exposes more hydrophobic groups which facilitate HMW aggregation. The HMW aggregation results from highly hydrophobic proteins which tend to become thermodynamically more stable.

Effect of L-4-oxalysine on ultrastructures of liver cells in mice

Mice were given ig L-4-oxalysine (I-677) 10, 50, and 100 mg.kg-1.d-1 for 7 d. On d 8 the hepatocytes showed accumulation of lipid droplets followed by loss of matrices in cytoplasm. The total area of lipid droplets was far less than 25% of mean section of hepatocytes. The injury of mitochondria and RER was only found in the groups of medium and high dose. The lipidoses and regional topolysis of cytoplasm graduated away at same pace. After 4 wk the hepatocytes were restored to normal. Such finding suggests that the site of action of I-677 be at the cytoplasmic ground substance. The inhibition of protein synthesis causes a decrease in albumin carrier, that may be the main mechanism of steatosis of liver cells induced by I-677.

Immunomodulating Chinese herbal medicines

Traditional Chinese medicine always pays close attention to the strengthening of the patient's general resistance against illness, there are many Chinese herbs used for thousands of years are considered as tonics. Animal experiments and modern clinical trails have shown that quite a number herbs are immunologically active, and most of the tonics are excellent immunomodulating agents, such as polysaccharides or saponins isolated from Astragalus mongholicus, Acanthopanax senticosus and Panax notoginseng, which stimulated macrophages, promoted antibody formation, activated complement and increased T lymphocyte proliferation. Moreover, some of them were proved to be anti-irradiative and protected animals from liver intoxications. On the other hand, some anti-inflammative or anti-pyretic herbs such as Tripterygium wilfordii, Aconitum and Artemisiae species were proved to have immunosuppressive principles, some of them were now used clinically for the treatment of rheumatoid arthritis, chronic nephritis, systemic lupus erythematosis and various skin disorders. Pharmacological studies revealed that they have depressant effect on most of the humoral-immunity but not on the cell-mediated immunity. Some of them stimulated adrenal cortex functions and prolonged the survival time of transplanted allograft tissues.