[N-2-mercaptopropionyl-glycine improves recovery of myocardial stunning after reversible regional ischemia in conscious dogs]

In order to investigate the therapeutic effect of N-2-Mercaptopropionyl-glycine (MPG), a scavenger of hydroxyl radical, on postischemic myocardial dysfunction of 39 conscious unsedated dogs were undergone a 15 min occlusion of left anterior descending coronary artery followed by 48 hours of reperfusion. The treated dogs (n = 17) received an infusion of MPG (100 mg/kg.h) for 60 minutes (starting 15 minutes before occlusion) while the control dogs (n = 22) received normal saline. The result showed that there were no significant differences between the two groups in collateral blood flow determined by radioactive microsphere, occlusion vascular bed and hemodynamic variables. Systolic thickening fraction of ventricular wall (an index of regional myocardial function) was similar in both groups under baseline condition and during ischemia, whereas it (expressed as percent of baseline) was considerably greater in treated dogs at 2, 3, 4, 5, 6 hours of reperfusion. Much more significant recovery was observed in the dogs with collateral flow less than 10% in MPG group. The exponential regression analysis showed that the lower the collateral flow, the greater the recovery of function in treated dogs. It is concluded that MPG improves recovery of myocardial function after reversible regional ischemia, especially with lower collateral blood flow.

Preproopiomelanocortin and preprodynorphin mRNA expressions in rat brain after electroacupuncture + droperidol

AIM

To study the expression of preproopiomelanocortin (POMC) and preprodynorphin (PPD) mRNA following the combination of electroacupuncture (EA) with droperidol (Dro), a dopamine receptor antagonist.

METHODS

The brains and spinal cords of Sprague-Dawley rats were sectioned after combination of EA with Dro, and the gene expression was investigated using nonradioactive in situ hybridization histochemistry (ISHH).

RESULTS

Ten hours after EA, the POMC mRNA expression was enhanced; the expression was further enhanced when EA was combined with Dro. The expression of PPD mRNA showed regional difference in central nervous system (CNS): in spinal cord, EA enhanced the PPD mRNA expression and the combination of EA with Dro further promoted the expression; in the brain, the PPD mRNA expression after EA or combination of EA with Dro showed no obvious change in most regions (caudate-putamen, accumbens, arcuate nucleus of hypothalamus) or was decreased in supraoptic nucleus.

CONCLUSION

Dro combined with EA promoted the expression of POMC mRNA in CNS and PPD mRNA in spinal cord, but reduced or had no effect on PPD mRNA expression in the brain.

Suprabasal expression of a dominant-negative RXR alpha mutant in transgenic mouse epidermis impairs regulation of gene transcription and basal keratinocyte proliferation by RAR-selective retinoids

To determine whether 9-cis retinoic acid receptors (RXRs) regulate the biological activity of all-trans retinoic acid (tRA) and its receptors (RARs) in skin, we have targeted a dominant-negative RXR alpha (dnRXR alpha) lacking transactivation function AF-2 to differentiated suprabasal keratinocytes in the epidermis of transgenic mice. Driven by the suprabasal-specific keratin-10 gene promoter, expression of dnRXR alpha severely reduced the ability of RAR-selective ligands tRA and CD367 to induce epidermal mRNA levels of the CRABPII, CRBPI, and CRBPII genes, which contain RA-responsive elements (RAREs) DR1 and/or DR2. It also reduced gene-specific, synergistic induction of CRBPI mRNA by a combination of CD367 and RXR-selective SR11237. Like endogenous RXR alpha, dnRXR alpha in epidermal nuclear extracts from the transgenic mice competitively formed heterodimers with endogenous RAR gamma on RAREs, suggesting that dnRXR alpha impairs retinoid signaling by competing with endogenous RAR gamma-RXR alpha heterodimers. Histologically, the epidermis of dnRXR alpha mice showed no detectable developmental abnormalities. Surprisingly, in adult animals, the suprabasal expression of dnRXR alpha significantly reduced the ability of topically applied tRA to stimulate proliferation of undifferentiated keratinocytes in the basal layer of epidermis. RXR-selective ligands alone had no detectable effects on both normal and transgenic mouse epidermis. Accordingly, we suggest that in vivo: (1) in suprabasal keratinocytes, retinoids regulate gene transcription via RAR-RXR heterodimers in which RAR confers a predominant ligand response, whereas RXR AF-2 is required for liganded RAR AF-2 to efficiently trans-activate target genes, and (2) this suprabasal RXR-assisted mechanism indirectly regulates proliferation of basal keratinocytes likely via intercellular signaling.

Free radical activity and pro-inflammatory effects of particulate air pollution (PM10) in vivo and in vitro

BACKGROUND

Epidemiological evidence has implicated fine particulate air pollution, particularly particles less than 10 microns in diameter (PM10), in the development of exacerbations of asthma and chronic obstructive pulmonary disease (COPD) although the mechanism is unknown. The hypothesis that PM10 particles induce oxidant stress, causing inflammation and injury to airway epithelium, was tested.

METHODS

The effects of intratracheal instillation of PM10 was assessed in rat lungs (three per group). Inflammatory cell influx was measured by bronchoalveolar lavage (BAL) and air space epithelial permeability was assessed as the total protein in BAL fluid in vivo. The oxidant properties of PM10 particles were determined by their ability to cause damage to plasmid DNA and by changes in reduced (GSH) and oxidised (GSSG) glutathione. The effects of PM10 particles were compared in some experiments with those of fine (CB) and ultrafine (ufCB) carbon black particles.

RESULTS

Six hours after intratracheal instillation of PM10 there was an influx of neutrophils (up to 15% of total cells in BAL fluid) into the alveolar space, increased epithelial permeability, the mean (SE) total protein in the BAL fluid increasing from 0.39 (0.01) to 0.62 (0.01) mg/ml, and increased lactate dehydrogenase (LDH) concentrations in the BAL fluid. An even greater inflammatory response was seen following intratracheal instillation of ufCB but not following CB instillation. PM10 particles had free radical activity in vivo, as shown by a decrease in GSH levels in the BAL fluid from 0.36 (0.05) to 0.25 (0.01) nmol/ml following instillation. The free radical activity of PM10 was confirmed in vitro by its ability to deplete supercoiled plasmid DNA, an effect which could be reversed by mannitol, a specific hydroxyl radical scavenger. BAL fluid leucocytes from rats treated with PM10 produced greater amounts of nitric oxide (NO), measured as nitrite (control 3.07 (0.33), treated 4.45 (0.23) microM/1 x 10(6) cells), and tumour necrosis factor alpha (control 21.0 (3.1), treated 179.2 (29.4) units/l x 10(6) cells) in culture than those obtained from control animals. Since the PM10 preparation was contaminated with small amounts of filter fibres due to the extraction process, the effects of instillation of filter fibres alone was assessed. These studies showed that filter fibres did not account for the proinflammatory and injurious effects of the PM10 suspension.

CONCLUSIONS

These findings provide evidence that PM10 has free radical activity and causes lung inflammation and epithelial injury. These data support the proposed hypothesis for the mechanism by which particulate air pollution causes adverse effects in patients with airways diseases.

Role of Th1 and Th2 cells in anterior chamber-associated immune deviation

The immunological privilege of the anterior chamber (AC) of the eye is due, at least in part, to a selective antigen-specific down-regulation of delayed-type hypersensitivity (DTH) and a normal induction of antibody responses: a phenomenon that has been termed anterior chamber-associated immune deviation (ACAID). This dichotomy in the systemic immune responses is suggestive of a T-helper type-2 (Th2)-dominated immune phenotype in which a Th2 cell population is preferentially activated and cross-regulates T-helper type-1 (Th1) effector elements. This hypothesis was tested by comparing the cytokine pattern of antigen-pulsed spleen cells from mice primed in the anterior chamber with antigens that induce ACAID with responses in hosts primed with antigens that do not induce ACAID. The results indicated that CD4+ spleen cells from hosts primed in the AC with antigens that induce ACAID produced significant quantities of interleukin-10 (IL-10) but insignificant levels of IL-2, IL-4 and interferon-gamma (IFN-gamma). In contrast, hosts primed in the AC with antigens that do not induce ACAID, but instead elicit normal DTH, displayed cytokine patterns indicative of a Th1 response significant quantities of IL-2 and IFN-gamma were produced while IL-4 and IL-10 secretion was insignificantly different from normal controls. The immunological phenotype of the AC-primed hosts could be altered by systemic treatment with antibodies against either a Th1 cytokine (IFN-gamma) or a Th2 cytokine (IL-10). Hosts treated with anti-IL-10 antibody and subsequently primed in the AC with ACAID-inducing antigens developed normal DTH responses, while hosts treated with anti-IFN-gamma antibody and primed in the AC with antigens that normally produce positive DTH responses failed to develop positive DTH collectively the results support the proposition that immune privilege in the AC of the eye is due to the selective activation of a Th2 population that cross-regulates Th1 responses.

Implantation of IL-2-containing osmotic pump prolongs the survival of superantigen-reactive T cells expanded in mice injected with bacterial superantigen

In the present study we investigated the mechanism of deletion of superantigen (sAg)-reactive T cells expanded in sAg-injected mice. In staphylococcal enterotoxin A (SEA)-injected mice, IL-2 activity in serum peaked at 1 to 3 h and the expression of IL-2R alpha-chain (IL-2R alpha) on SEA-reactive (V beta 3+, or V beta 11+) T cells peaked at 6 to 12 h after the injection. Expansion of V beta 3+ or V beta 11+ T cells peaked at 2 days after the injection when most of these T cells were IL-2R alpha negative, and IL-2 activity was not detected at all in serum, suggesting the involvement of IL-2 deprivation in the deletion of expanded T cells. Implantation of an osmotic pump containing human rIL-2 (IL-2 pump) prolonged the expanded states of V beta 3+ or V beta 11+ T cells in SEA-injected C57BL/6 mice and of V beta 8+ T cells in SEB-injected MRL +/+ and Fas Ag-defective MRL-Ipr/Ipr mice. Adult thymectomy did not change at all the effect induced by implantation of IL-2 pump. DNA fragmentation was blocked substantially in mice co-treated with SEA and IL-2 pump. In addition, CD4+ T cell blasts, obtained by in vitro stimulation with rIL-2 of splenic CD4+ T cells from mice co-treated with SEA and IL-2 pump, produced substantial amounts of IL-2 upon restimulation with SEA. These results indicate that deprivation of IL-2 is deeply involved in the deletion of expanded sAg-reactive T cells and their anergy induction in sAg-injected mice.

Implantation of IL-2-containing osmotic pump prolongs the survival of superantigen-reactive T cells expanded in mice injected with bacterial superantigen

In the present study we investigated the mechanism of deletion of superantigen (sAg)-reactive T cells expanded in sAg-injected mice. In staphylococcal enterotoxin A (SEA)-injected mice, IL-2 activity in serum peaked at 1 to 3 h and the expression of IL-2R alpha-chain (IL-2R alpha) on SEA-reactive (V beta 3+, or V beta 11+) T cells peaked at 6 to 12 h after the injection. Expansion of V beta 3+ or V beta 11+ T cells peaked at 2 days after the injection when most of these T cells were IL-2R alpha negative, and IL-2 activity was not detected at all in serum, suggesting the involvement of IL-2 deprivation in the deletion of expanded T cells. Implantation of an osmotic pump containing human rIL-2 (IL-2 pump) prolonged the expanded states of V beta 3+ or V beta 11+ T cells in SEA-injected C57BL/6 mice and of V beta 8+ T cells in SEB-injected MRL +/+ and Fas Ag-defective MRL-Ipr/Ipr mice. Adult thymectomy did not change at all the effect induced by implantation of IL-2 pump. DNA fragmentation was blocked substantially in mice co-treated with SEA and IL-2 pump. In addition, CD4+ T cell blasts, obtained by in vitro stimulation with rIL-2 of splenic CD4+ T cells from mice co-treated with SEA and IL-2 pump, produced substantial amounts of IL-2 upon restimulation with SEA. These results indicate that deprivation of IL-2 is deeply involved in the deletion of expanded sAg-reactive T cells and their anergy induction in sAg-injected mice.

Transcriptional elongation and cancer. Tumorigenesis

Recent discoveries indicate that transcriptional elongation is an important regulatory step in gene expression, and that deregulation of elongation can lead to the development of certain malignancies.

Kinetics of serum granulocyte-colony stimulating factor (G-CSF) concentration and G-CSF receptor expression during G-CSF treatment of cyclophosphamide-treated mice

We analyzed the kinetics of leukocyte number, serum granulocyte colony stimulating factor (G-CSF) concentration, and G-CSF receptor expression in mice after recombinant human (rh) G-CSF treatment. Intraperitoneal (i.p.) injection with 200 mg/kg of cyclophosphamide (CP) induced a transient decrease of leukocyte number in blood and spleen. Daily i.p. inoculation of a low dose of rhG-CSF (1 microgram/kg/day) from day 1 of CP injection for 8 days resulted in a significant increase of spleen cell number from day 5 to day 8, while serum rhG-CSF concentration decreased to an undetectable level on day 7. Furthermore, daily i.p. inoculation of high dose rhG-CSF (100 micrograms/kg/day) for 5 days to CP-injected mice induced a significant increase of leukocytes from day 3 to day 6 in both peripheral blood and spleen, and the increase was higher than that observed after low dose G-CSF treatment. In the course of the high dose rhG-CSF treatment, however, serum rhG-CSF concentration decreased from day 3, which is earlier than the decrease of serum rhG-CSF seen after low dose rhG-CSF treatment. A reverse transcription-polymerase reaction analysis of mRNA expression showed that spleen cells from high dose rhG-CSF-treated mice on day 4 and day 6 expressed more than 10 times higher levels of membrane G-CSF receptors than did those obtained before rhG-CSF treatment. All these results suggest that decrease of serum G-CSF during daily G-CSF treatment does not always indicate neutralization of G-CSF, but implies that the inoculated G-CSF is still stimulating granulocytes and their precursors by binding to membrane G-CSF receptors which are up-regulated by G-CSF treatment. This observation is important when we measure pharmacokinetics of G-CSF in patients chronically injected with G-CSF.

Mechanisms of cigarette smoke induced increased airspace permeability

BACKGROUND

Increased epithelial permeability of the airspaces occurs commonly in the lungs of cigarette smokers. It is likely to be important in augmenting the inflammatory response in the airspaces and hence may have a role in the pathogenesis of emphysema. It has previously been shown that intratracheal instillation of cigarette smoke condensate induces increased epithelial permeability in vivo in rats and in vitro in epithelial cell monolayers, associated with a disturbance in the lung antioxidant, glutathione (GSH). The aim of this study was to assess the role of neutrophils, GSH, and tumour necrosis factor (TNF) in the increased epithelial permeability following intratracheal instillation of cigarette smoke condensate.

METHODS

Epithelial permeability of the airspaces was measured in rat lungs as the passage of intratracheally instilled 125-iodine labelled bovine serum albumin (BSA) into the blood. The permeability of a monolayer of human type II alveolar epithelial cells to 125I-BSA was also measured.

RESULTS

Cigarette smoke condensate produced a 59.7% increase in epithelial permeability over control values peaking six hours after instillation and returning to control values by 24 hours. Depletion of neutrophils and, to a lesser extent, macrophages by an intraperitoneal injection of antineutrophil antibody did not influence the increased epithelial permeability induced by cigarette smoke condensate. Although instillation of human recombinant TNF alpha produced an increase in epithelial permeability in the rat lung from 0.62 (0.61)% to 1.27 (0.08)%, only a trivial amount of TNF alpha was detected in bronchoalveolar lavage (BAL) fluid in vivo or in culture medium from BAL leucocytes obtained from animals treated with cigarette smoke condensate (94.9 (28.8) units/ml). Furthermore, antiTNF antibody did not abolish the increased epithelial permeability produced by cigarette smoke condensate. The role of GSH was assessed by measuring the changes in both the reduced (GSH) and oxidised form (GSSG) in lung tissue and in BAL fluid. One hour after instillation of cigarette smoke condensate there was a marked fall in the GSH content in the lung (from 809.8 (31.8) to 501.7 (40.5) nmol/g) in association with increased GSSG levels (from 89.8 (2.7) to 148.7 (48.8) nmol/g). This was followed by a return of GSH levels to control values, with a concomitant decrease in GSSG levels six hours after instillation. GSH levels in BAL fluid fell dramatically following cigarette smoke condensate (from 2.56 (0.30) to 0.31 (0.21) nmol/ml) and this fall was sustained up to six hours after instillation of cigarette smoke condensate.

CONCLUSIONS

These studies suggest that neutrophils and TNF do not have a major role in the increased epithelial permeability induced by cigarette smoke condensate. However, the data support a role for the depletion of the antioxidant glutathione in the increased epithelial permeability caused by cigarette smoke condensate.

Membrane anchoring and release of carboxypeptidase M: implications for extracellular hydrolysis of peptide hormones

Carboxypeptidase M (CPM) was discovered as a membrane-bound B-type carboxypeptidase which is widely distributed in a variety of tissues and cells. The amino acid sequence of CPM indicated that the C-terminal hydrophobic region might be a signal for membrane attachment via a glycosylphosphatidylinositol (GPI) anchor. This was demonstrated by [3H)ethanolamine labeling of Madin Darby canine kidney (MDCK) cells which resulted in labeling of the membrane anchor of CPM as shown by immunoprecipitation, polyacrylamide gel electrophoresis and autoradiography. Trypsin released CPM from the membrane, resulting in removal of the radiolabeled ethanolamine. Carboxypeptidase activity was spontaneously and continuously released from MDCK cells into the medium. The released enzyme is a soluble form of CPM as shown by Triton X-114 partitioning, immunoprecipitation, Western blotting, inhibition studies and its neutral pH optimum. CPM was also found in soluble form in biological fluids such as urine and amniotic fluid where it is the primary enzyme that hydrolyzes epidermal growth factor (EGF), producing des-Arg53-EGF. These data indicate that CPM is involved in peptide metabolism on both the cell surface and in extracellular fluids.

Pharmacology and molecular action of retinoids and vitamin D in skin

All-trans retinoic acid and 1,25-dihydroxyvitamin D3 are biologically active hormones derived from metabolism of vitamins A and D, respectively. Their cellular effects in physiology and pharmacology are mediated mainly through their nuclear receptors, retinoic acid receptors (RARs), and vitamin D receptor (VDR), which are members of the steroid/thyroid hormone receptor superfamily. The nuclear receptor superfamily is a group of hormone (ligand)-dependent transcription factors that bind to specific DNA recognition sequences located in the promotor region of target genes and modulate the gene transcription. Both RARs and VDR bind to DNA in the form of heterodimers with retinoid X receptor (RXR) as the key partner. In human skin epidermis, endogenous RAR and VDR bind to their respective enhancer elements as heterodimers (RAR-RXR, VDR-RXR) and not as homodimers. 9-cis retinoic acid is the natural ligand for RXRs. Because RXR heterodimerizes with either RARs or VDR, it functions as a key protein in the overall retinoid or vitamin D response of a given biological system. The contribution of RXRs in coregulating these signaling pathways is likely to depend on the abundance of the RXRs within target cells, the relative amounts of other receptors with which they can dimerize, and the availability of their ligands (hormones). Understanding each of these components in human skin in vivo will lead to practical applications in dermatologic therapeutics.

Augmentation of TNF-alpha production, NK cell activity and IL-12 p35 mRNA expression by methionine enkephalin

AIM

To study the host immune surveillance functions by the neuropeptide methionine enkephalin (met-enk).

METHODS

To measure the effects of met-enk on NK activity, the production and gene expression of anti-tumor cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-12 (IL-12) in vitro and in vivo.

RESULT

Met-enk promoted NK activity at 1 x 10(-8) - 1 x 10(-5) mol.L-1, increased TNF-alpha production both in vitro and in vivo, and enhanced IL-12 p35 gene transcription after ip 0.1 mg.kg-1 for 6 d.

CONCLUSION

The up-regulating effects of met-enk contribute to the host neuro-immunomodulating mechanism against tumors and invading antigens. Enkephalins and endorphins were originally described as the endogenous ligands for the morphine receptors in the brain. In addition to their central nervous activity, an immunomodulating action of the enkephalins was first reported in 1979. Methionine enkephalin (met-enk) regulated a variety of immunological responses, including enhancing the proliferation of human peripheral lymphocytes and mouse spleen cells, regulating antibody production, natural killer cells (NK) activity and synthesis of a number of cytokines. These results suggested that met-enk might be used to elevate the body resistance to cancer and other diseases, or diminish autoimmune responses which are detrimental to host. To elucidate that met-enk has the activity of anti-tumor through related immune regulating responses, this study is to investigate the effects of met-enk on immune surveillance and immune defence functions.

Intramolecular inhibition of activating transcription factor-2 function by its DNA-binding domain

ATF-2 is a cellular basic region-leucine zipper (bZIP) transcription factor that can mediate diverse transcriptional responses, including activation by the adenovirus Ela protein. ATF-2 contains an activation domain, required for transcriptional activity, but in the absence of an appropriate inducer, full-length ATF-2 is transcriptionally inactive. Here we have investigated the mechanism underlying this regulated inhibition of ATF-2 transcriptional activity. We show that the region of ATF-2 that suppresses the activation region is the bZIP DNA-binding domain and that maximal inhibition requires both the basic region and leucine zipper subdomains. Inhibition is activation domain specific: The ATF-2 bZIP suppresses the ATF-2 and the related Ela activation domains but not acidic- and glutamine-rich activation domains. In vitro protein interaction assays demonstrate that the ATF-2 activation domain and bZIP specifically bind to one another. Finally, we show that bZIP-mediated inhibition can be modulated in a cell-type-specific manner by another sequence element within ATF-2. On the basis of these and other data, we propose that the ATF-2 bZIP and activation domain are engaged in an inhibitory intramolecular interaction and that inducers of ATF-2 disrupt this interaction to activate transcription.

Harmful effects of MSG on function of hypothalamus-pituitary-target gland system

It has been demonstrated that neonatal administration of monosodium glutamate (MSG) results in a clearly defined lesion of the arcuate nucleus (AN) of the hypothalamus. The present study shows that fat was accumulated in the abdomen of male rats treated with MSG; weights of the body, pituitary and testis were lower; beta-EP content in hypothalamus decreased while L.EnK content increased; serum LH, FSH, TSH, GH and TS levels all decreased in varying degrees while serum PRL level significantly increased. The cAMP content lowered in pituitary, but nor in testes; clear histological changes occurred in testicular tissue; Se-GSH-Px activity in both testis and adrenal gland lowered while LPO level significantly increased. Both Se-GSH-Px activity and LPO level in liver increased. These results indicate that MSG is harmful to the function of the hypothalamus-pituitary-target system of neonatal rats.

Glutathione homeostasis in alveolar epithelial cells in vitro and lung in vivo under oxidative stress

We studied the acute effects of cigarette smoke condensate (CSC), H2O2, and tumor necrosis factor (TNF)-alpha on the glutathione (GSH) redox system in a human type II epithelial cell line (A549) in vitro. CSC, in vitro and in vivo after intratracheal instillation of CSC in the rat, produced a depletion of intracellular soluble GSH, concomitant with GSH-conjugate formation, without significant elevation of oxidized GSH (GSSG), protein-GSH mixed disulfides (PrSSG), nor any GSH efflux from the cells. By contrast, H2O2 (500 microM) after 5-min exposure to A549 cells caused significant depletion of intracellular GSH associated with an efflux of GSSG and a significant increase in the formation of PrSSG. TNF-alpha, in concentrations of 100 U/ml and 1,000 U/ml, produced a significant depletion of GSH in A549 cells after 4- and 24-h exposure, with an associated elevation of GSSG. The activities of glutathione peroxidase, gamma-glutamylcysteine synthetase, and glucose-6-phosphate dehydrogenase were significantly decreased in epithelial cells and in rat lungs after CSC exposure, without change in glutathione S-transferase and glutathione reductase activities. By contrast, H2O2 and TNF-alpha did not alter these enzyme activities in epithelial cells. Thus GSH depletion and alteration in enzyme activities in alveolar epithelial cells by CSC, H2O2, and TNF-alpha occur by different mechanisms.

On modeling the vibrational spectra of 14-s-cis retinal conformers in bacteriorhodopsin

The vibrational properties of 13-cis, 14-s-trans and 13-cis, 14-s-cis protonated retinal Schiff base model compounds are explored with MNDO calculations. In particular, the effect of isomerization about the C14-C15 single bond on the vibrational properties of the deuterium in-plane rocking vibrations has been examined. Our MNDO calculations, using a variety of lysine models, lysine conformations and Schiff base charge environments, demonstrate that the C14-D and C15-D in-plane rocking vibrations in the 14,15-dideuterio retinal protonated Schiff base are strongly coupled in 13-cis, 14-s-cis molecules producing a splitting of ca. 80 cm-1 between the symmetric and antisymmetric rocking mode combinations but that these modes are only weakly coupled in 14-s-trans molecules. This analysis demonstrates that the 14,15-dideuterio labeling method developed earlier for determining C14-C15 conformation (S.P.A. Fodor, W. T. Pollard, R. Gebhard, E. M. M. van den Berg, J. Lugtenburg and R. A. Mathies, Proc. Natl. Acad. Sci. USA, 85, (1988) 2156-2160) is valid, and hence that the structure of the retinal chromophore in bacteriorhodopsin's L550 intermediate is 13-cis, 14-s-trans. The reasons for the misleading conclusions derived from MNDO calculations performed earlier by Schulten and Tavan are discussed.

Expressions of preproenkephalin mRNA during electroacupuncture analgesia enhanced by fenfluramine

AIM

To study the changes of preproenkephalin (PPE) mRNA in rat brain in response to electroacupuncture (EA) combined with fenfluramine (Fen), a releaser of 5-HT.

METHODS

In situ hybridization histochemistry technique was used to observe the expression of PPE mRNA in rat brain during EA analgesia potentiated by Fen.

RESULTS

The greatest relative increase of PPE mRNA was seen in lumbar spinal cord (laminae I & II), nucleus raphe magnus, dorsal raphe nucleus, periaqueductal gray, interpeduncular nucleus, preoptic lateral area, amygdala nucleus and caudate-putamen (P < 0.01, vs NS + EA). Moderate increases were found in lateral septal, preoptic medial area, hypothalamus ventromedial nucleus, lumbar spinal laminae III & IV (P < 0.05, vs NS + EA). Thalamus showed no statistical significant change in PPE mRNA.

CONCLUSION

The enhancing of PPE mRNA in relative brain nuclei is involved in potentiating action of Fen on EA.

Effect of morphine on interleukin-1 and tumor necrosis factor alpha production from mouse peritoneal macrophages in vitro

AIM

To study the influence of morphine on lymphokine production from mouse peritoneal macrophages (PM phi).

METHODS

The productions of interleukin-1 (IL-1) and tumor necrosis factor (TNF-alpha) from PM phi under various concentrations of morphine with or without naloxone were measured by testing thymocyte proliferation and L929 cell lysis in vitro.

RESULTS

Both morphine (1 x 10(-8) - 1 x 10(-3) mol L-1) and naloxone (50 mumol L-1) inhibited IL-1 production from mouse PM phi primed by sodium thioglycolate. Naloxone did not block the inhibitory effect of morphine. TNF-alpha production from PM phi was inhibited by only high concentration (1 mmol L-1) of morphine which was not blocked by naloxone.

CONCLUSION

Morphine had a direct inhibitory effect on PM phi, which was not mediated by opioid receptor of PM phi.

Photostationary state compositions of retinal and related compounds included in beta-lactoglobulin. Effects of protein host on isomer distribution of polyene substrates

The UV-visible absorption spectra and photostationary state compositions of retinal (or the related C-18 ketone, 3-dehydroretinal and the C-22 aldehyde) imbedded in the binding cavity of beta-lactoglobulin (BLG) are consistent with the view that the carbonyl group of these polyenes are hydrogen-bonded with the protein host, most likely with the lone protonated lysine residue in the binding pocket. Patterns of variation in photochemical behavior of the imbedded chromophore versus that in solution are discussed in terms of possible specific protein-substrate interactions. The results are also compared with that of the methyl ether of retinol where similar hydrogen bonding is not possible.

The role of tumor necrosis factor in increased airspace epithelial permeability in acute lung inflammation

Increased airspace epithelial permeability is an early event in lung inflammation and injury. In this study, we have developed a rat model to study the mechanisms of the epithelial permeability to 125iodine-labeled bovine serum albumin (125I-BSA), instilled intratracheally during acute lung inflammation. Epithelial permeability was measured as the percentage of instilled 125I-BSA appearing in the blood. The increase in epithelial permeability induced by intratracheal instillation of heat-killed Corynebacterium parvum produced a peak influx of neutrophils into the bronchoalveolar space at 16 h, which occurred after the peak increase in epithelial permeability (8 h). The increased epithelial permeability induced by C. parvum did not appear to be protease- or oxidant-mediated. Depletion of peripheral blood neutrophils was achieved by an intravenous injection of anti-neutrophil polyclonal antibody. The consequent profound reduction in neutrophil and macrophage influx into the airspaces 8 h after instillation of C. parvum reduced the epithelial permeability to control values. Bronchoalveolar lavage (BAL) leukocytes from rats 8 h, but not 16 h, after treatment with C. parvum caused a modest increase in epithelial permeability when re-instilled intratracheally into control rat lungs. Separation of the leukocytes before re-instillation indicated that macrophages rather than neutrophils were predominantly responsible for the increased epithelial permeability. The presence of dramatically increased levels of tumor necrosis factor (TNF) in BAL 8 h in contrast to a slight increase in BAL 16 h after C. parvum, the release of TNF from 8 h macrophages, the increased epithelial permeability induced by TNF in epithelial monolayers in vitro, and the inhibition of C. parvum-induced epithelial permeability by TNF antibody support the premise that TNF is a major player in the increased epithelial permeability that occurs during C. parvum-induced acute alveolitis.

Anti-leukocyte function-1 antibody treatment prevents the rejection of intraocular regressor tumors and their metastases

The role of the cell adhesion molecules, LFA-1 and ICAM-1, in intraocular tumor rejection was examined using four different syngeneic intraocular regressor tumors and four different inbred mouse strains. All four tumors undergo T cell-dependent immune rejection in the syngeneic host. Two of the tumors, D5.1G4 melanoma and P91 mastocytoma, undergo rejection by a cytotoxic T lymphocyte-like immune process. The other two tumors, UV5C25 fibrosarcoma and 124E2 melanoma, are rejected by a process that appears to be mediated by delayed-type hypersensitivity. Systemic administration of anti-LFA-1 prevented the rejection of all four categories of tumors. By contrast, similar in vivo treatment with anti-ICAM-1 antibody did not inhibit tumor rejection. The effect of anti-LFA-1 and anti-ICAM-1 antibody treatment on the rejection of metastases arising from intraocular P91 tumors was also examined and found to be highly dependent upon normal LFA-1 function since antibody treatment with anti-LFA-1 prevented the rejection of metastases. Treatment with anti-ICAM-1 antibody alone had no appreciable effect on the rejection of metastases. The results from this study indicate that the expression and function of LFA-1 is crucial for the generation of immune responses to tumor antigens originating within the eye and the expression of tumor immunity within the eye and at distant sites.