Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit interleukin-12 transcription by regulating nuclear factor kappaB and Ets activation

The vasoactive intestinal peptide (VIP) and the structurally related neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) act as "macrophage-deactivating factors". We showed previously that VIP and PACAP inhibit the production of macrophage-derived tumor necrosis factor-alpha, interleukin (IL)-6, nitric oxide, and IL-12. This study examines the molecular mechanisms involved in the VIP/PACAP inhibition of IL-12 production. VIP and PACAP inhibit IL-12 (p40) gene expression by affecting both NF-kappaB binding and the composition of the Ets-2 binding complex. Both neuropeptides prevent the activation-induced nuclear translocation of the NF-kappaB components p65 and c-Rel by inhibiting the reduction in cytoplasmic IkappaBalpha. Moreover, VIP and PACAP inhibit the synthesis of the interferon responsive factor-1. The decrease in nuclear interferon responsive factor-1 and c-Rel results in alterations of the Ets-2-binding complex. Two transduction pathways, a cAMP-dependent and a cAMP-independent pathway, are involved in the inhibition of IL-12 gene expression and appear to differentially regulate the transcriptional factors involved. Because IL-12 participates in T cell activation and cytolytic T lymphocyte activity and promotes the differentiation of T helper cells into the Th1 subset, the understanding of the mechanisms that affect IL-12 production in normal and pathological conditions could contribute to immune response-based therapies or vaccine designs.

VIP and PACAP differentially regulate the costimulatory activity of resting and activated macrophages through the modulation of B7.1 and B7.2 expression

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP), two structurally related neuropeptides produced and/or released within the lymphoid microenvironment, modulate numerous immune functions. Although primarily antiinflammatory in nature, VIP and PACAP also affect resting macrophages. In this study, we report on in vitro and in vivo dual effects of VIP/PACAP on the expression of B7.1 and B7.2 and on the costimulatory activity for T cells in unstimulated and LPS/IFN-gamma-activated macrophages. VIP and PACAP up-regulate B7.2, but not B7.1, expression and induce the capacity to stimulate the proliferation of naive T cells in response to soluble anti-CD3 or allogeneic stimulation. In contrast, both neuropeptides down-regulate B7.1/B7.2 expression on LPS/IFN-gamma-activated macrophages and inhibit the endotoxin-induced costimulatory activity for T cells. Interestingly, both the stimulatory and the inhibitory effects of VIP/PACAP are mediated through the specific receptor VPAC1 and involve the cAMP/protein kinase A transduction pathway. The dual effect on B7.1 and B7.2 expression occurs at both mRNA and protein level and correlates with the VIP/PACAP regulation of the macrophage costimulatory activity. Through their regulatory role for resting and activated macrophages, VIP and PACAP act as endogenous participants in the control of immune homeostasis. Their effects depend not only on the timing of their release, but also on the activation and differentiation state of the neighboring immune cells.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide stimulate the induction of Th2 responses by up-regulating B7.2 expression

Vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP), two structurally related neuropeptides produced within the lymphoid microenvironment, modulate several immunologic functions. We have recently demonstrated that VIP and PACAP enhance the macrophage costimulatory activity for naive CD4+ T cells exposed to allogeneic or anti-CD3 stimuli through the differential regulation of the B7 costimulatory molecules. In this study, we report on the role of VIP and PACAP on macrophage B7 expression and costimulatory function for Ag-primed CD4+ T cells, and on the macrophage-induced regulation of Th1/Th2 differentiation in vitro and in vivo. VIP and PACAP up-regulate the costimulatory activity of macrophages for Ag-primed CD4+ T cells. VIP-/PACAP-treated macrophages gain the ability to induce Th2-type cytokines such as IL-4 and IL-5 and reduce Th1-type cytokines such as IFN-gamma and IL-2. In vivo administration of VIP or PACAP in Ag-immunized mice reduce the numbers of IFN-gamma-secreting cells and enhance the numbers of IL-4-secreting cells. One of the consequences of the VIP-/PACAP-induced shift in cytokine profile is a change in the Ag-specific Ig isotype, increasing IgG1 and decreasing IgG2a levels. Finally, the preferential differentiation into Th2 effector cells after Ag stimulation induced by VIP-/PACAP-treated macrophages is mediated through the up-regulation of B7.2 expression.

Probable effect of photoperiod on seasonal variation in the nuclear volume of the adrenal cortex of viscacha (Lagostomus maximus maximus)

The neuroendocrine system regulates several organic functions such as reproduction, metabolism and adaptation to the environment. This system shows seasonal changes linked to the environment. The experimental model used in the present study was Lagostomus maximus maximus (viscacha). The reproduction of males of this species is photoperiod dependent. Twenty-four adult male viscachas were captured in their habitat at different times during one year. The adrenal glands were processed for light microscopy. Serial cuts were stained with hematoxylin-eosin for the morphometric study, and 100 nuclei of each zone of the adrenal cortex were counted per animal. Data were analyzed statistically by ANOVA and the Tukey test. The cells of the glomerulosa zone are arranged in a tube-shaped structure. The fasciculata zone has large cells with central nuclei and clearly visible nucleoli and with a vacuolar cytoplasm. In the reticularis zone there are two of types of cells, one with a nucleus of fine chromatin and a clearly visible nucleolus and the other with nuclear pycnosis. Morphometric analysis showed maximum nuclear volumes during the February-March period with values of 133 +/- 7.3 microm3 for the glomerulosa, 286.4 +/- 14.72 microm3 for the fasciculata, and 126.3 +/- 9.49 microm3 for the reticularis. Minimum nuclear volumes were observed in August with values of 88.24 +/- 9.9 microm3 for the glomerulosa, 163.7 +/- 7.78 microm3 for the fasciculata and 64.58 +/- 4.53 microm3 for the reticularis. The short winter photoperiod to which viscacha is subjected could inhibit the adrenal cortex through a melatonin increase which reduces the nuclear volume as well as the cellular activity.

Shedding of membrane-bound CD14 from lipopolysaccharide-stimulated macrophages by vasoactive intestinal peptide and pituitary adenylate cyclase activating polypeptide

Macrophage activation and deactivation play essential roles in the initiation and maintenance of a successful immune response. Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP), two structurally related neuropeptides, act as macrophage deactivating factors. We reported previously that VIP and PACAP inhibit IL-6, IL-12, TNF alpha and NO production, and enhance IL-10 production, from lipopolysaccharide (LPS)-stimulated macrophages. In this study, we demonstrate that VIP and PACAP down-regulate the expression of CD14, the membrane-bound LPS receptor, by inducing its rapid shedding. The soluble CD14 released by VIP and PACAP corresponds in size to the soluble CD14 released by PMA. Neither VIP/PACAP nor PMA, affect the steady-state levels of CD14 mRNA. The CD14 shedding induced by VIP/PACAP is mediated through the PAC1 specific receptors and the major transduction pathway involves the protein kinase C (PKC). The VIP/PACAP inhibition of TNF alpha and NO occurs through both CD14-dependent and -independent mechanisms, whereas the inhibition of IL-6 production appears to be strictly CD14-dependent. The shedding of CD14 by VIP and PACAP represents an important mechanism by which these neuropeptides limit the macrophage inflammatory response.

Synthesis of Novel Polyethers in a Geometrically Precise Conformation

[reaction: see text] A convergent design for the preparation of a polyoxyethylene-based channel molecule is presented, and the synthesis of the key unit 2 required for the projected construction is described. The essential elements of the design included face to face oriented macrorings spaced by rigid trans-fused oxanes. The strategy combines conformational predictability of C-linked oxanyl systems and ring-closing metathesis for the synthesis of crown ethers with engineerable ion-binding abilities.

[Scintigraphy with 99MTc-HMPAO labeled leukocytes and computed tomography in the diagnosis of vascular graft infection. A comparative study]

The purpose of this work was to compare the results obtained with a scitigraphy using 99mTc-HMPAO labeled leukocyte and a computed tomography (CT) in the diagnosis of vascular graft infection (VGI). We carried out 22 studies with both scintigraphy and CT in 20 patients with vascular grafts with VGI suspicion. One patient had two grafts, thus a total of 23 grafts were analyzed. In addition, 6 control studies were performed. The persistent increase in leukocyte uptake in the graft area was considered as evidence of VGI and the scintigraphy with HMPAO-99mTc labeled leukocytes. For the CT, the presence of perigraft fluid and/or gas collection in the graft bed was also considered to be evidence of VGI. The total number of VGI was 12. The VGI diagnosis was confirmed by culture in all cases. The sensitivity and specificity of the scintigraphy in the diagnosis of VGI was 100%, while the CT has a sensitivity of 58% and specificity of 91%. Five grafts presented pseudoaneurysm in distal aorto-bifemoral graft anastomosis. All theses cases were detected with CT and only one patient with pseudoaneurysms showed scintigraphic evidence of VGI. In addition, both techniques detected two soft tissue infections associated with cutaneous fistulae, one case of abdominal abscess and another of acute diverticulitis. The scintigraphy was also pathologic in one infection of the surgical wound while that the CT was negative. In conclusion, although both techniques are useful to evaluate patients with suspicion of VGI, the scintigraphy with 99m-Tc-HMPAO labeled leukocytes has been shown to be more sensitive than the CT in the assessment of patients with VGI suspicion.

The use of diffusion tensor imaging in quantifying the effect of dexamethasone on brain tumours

The role of dexamethasone in the treatment of patients with brain tumours remains poorly understood. In this study the self-diffusion parameters of extracellular water within primary intracranial tumours and peritumoural tissue, and their response to dexamethasone, have been measured using MR diffusion tensor imaging. Maps of the mean diffusivity <D> and two measures of diffusion anisotropy were obtained from six patients before, and typically 48-72h after, commencing dexamethasone treatment. A significant decrease in <D> of either tumour (p < 0.02) or oedematous brain (p < 0.04) was observed in three patients. No significant changes were noted in either of the two calculated diffusion anisotropy indices before and after steroid treatment in any of the six patients.

VIP and PACAP inhibit IL-12 production in LPS-stimulated macrophages. Subsequent effect on IFNgamma synthesis by T cells

Since IL-12 plays a central role against intracellular pathogens, and contributes to the pathogenesis of immune diseases, its regulation is essential. This study examines the effect of two neuropeptides, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP), on interleukin-12 (IL-12) production. VIP/PACAP inhibit IL-12 dose-dependently. Type 1 VIP receptor (VPAC1), and to a lesser degree type 2 VIP receptor (VPAC2), mediate the inhibition of IL-12, primarily through the cAMP/PKA pathway. VIP/PACAP inhibit the production of IL-12, IL-6, tumor necrosis factor alpha (TNFalpha), and interferon gamma (IFNgamma) in vivo in endotoxemic mice. The presence of VIP/PACAP in the lymphoid organs and the specific effects on cytokine production offer a physiological basis for their immunomodulatory role in vivo.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide prevent inducible nitric oxide synthase transcription in macrophages by inhibiting NF-kappa B and IFN regulatory factor 1 activation

High-output nitric oxide (NO) production from activated macrophages, resulting from the induction of inducible NO synthase (iNOS) expression, represents a major mechanism for macrophage cytotoxicity against pathogens. However, despite its beneficial role in host defense, sustained high-output NO production was also implicated in a variety of acute inflammatory diseases and autoimmune diseases. Therefore, the down-regulation of iNOS expression during an inflammatory process plays a significant physiological role. This study examines the role of two immunomodulatory neuropeptides, the vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP), on NO production by LPS-, IFN-gamma-, and LPS/IFN-gamma-stimulated peritoneal macrophages and the Raw 264.7 cell line. Both VIP and PACAP inhibit NO production in a dose- and time-dependent manner by reducing iNOS expression at protein and mRNA level. VPAC1, the type 1 VIP receptor, which is constitutively expressed in macrophages, and to a lesser degree VPAC2, the type 2 VIP receptor, which is induced upon macrophage activation, mediate the effect of VIP/PACAP. VIP/PACAP inhibit iNOS expression and activity both in vivo and in vitro. Two transduction pathways appear to be involved, a cAMP-dependent pathway that preferentially inhibits IFN regulatory factor-1 transactivation and a cAMP-independent pathway that blocks NF-kappa B binding to the iNOS promoter. The down-regulation of iNOS expression, together with previously reported inhibitory effects on the production of the proinflammatory cytokines IL-6, TNF-alpha, and IL-12, and the stimulation of the anti-inflammatory IL-10, define VIP and PACAP as "macrophage deactivating factors" with significant physiological relevance.

[Hypothyroidism in patients treated for laryngeal cancer: preliminary results]

OBJECTIVE

The reported incidence of hypothyroidism following surgery and/or irradiation for laryngeal cancer varies widely and the condition often is misdiagnosed. This study examines the incidence of thyroid dysfunction in patients with laryngeal cancer.

MATERIAL AND METHODS

Thyroid function tests were carried out in 75 patients with stage III and IV laryngeal carcinoma who were treated in our center with surgery (13 cases), radiotherapy (13 cases), or surgery and radiotherapy (49 cases) at least 18 months earlier. The clinical and histological variables recorded included T4 and TSH concentrations. Univariate and multivariate analysis was carried out with the BMDP program from UCLA (1995 version) to examine the relationship between hypothyroidism and clinical and pathological factors.

RESULTS

Twenty-nine patients (38.6%) had high TSH or low T4 concentrations and were diagnosed as having hypothyroidism. Hypothyroidism was significantly related with date of surgery (before 1993) and the treatment used on the neck. Thyroid function was rarely affected in patients who underwent functional neck dissection, but radical neck dissection and irradiation of the neck always were followed by hypothyroidism.

CONCLUSIONS

Thyroid testing should be performed routinely in the follow-up of laryngeal cancer. Many psychological symptoms attributed to total laryngectomy may be due to hypothyroidism, an easily treated condition.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit endotoxin-induced TNF-alpha production by macrophages: in vitro and in vivo studies

Vasoactive intestinal peptide (VIP) is a neuropeptide synthesized by immune cells that can modulate several immune aspects, including the function of cells involved in the inflammatory response, such as macrophages and monocytes. The production and release of cytokines by activated phagocytes are important events in the pathogenesis of ischemia-reperfusion injury. There is abundant evidence that the proinflammatory cytokine TNF-alpha is an important mediator of shock and organ failure complicating Gram-negative sepsis. VIP has been shown to attenuate the deleterious consequences of this pathologic phenomenon. In this study we have investigated the effects of VIP and the structurally related neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP38) on the production of TNF-alpha by endotoxin-activated murine peritoneal macrophages. Both neuropeptides rapidly and specifically inhibit the LPS-stimulated production of TNF-alpha, exerting their action through the binding to VPAC1 receptor and the subsequent activation of the adenylate cyclase system. VIP and PACAP regulate the production of TNF-alpha at a transcriptional level. In vitro results were correlated with an inhibition of both TNF-alpha expression and release in endotoxemic mice in vivo. The immunomodulatory role of VIP in vivo is supported by the up-regulation of VIP release in serum and peritoneal fluid by LPS and proinflammatory cytokines such as TNF-alpha, IL-1beta, and IL-6. These findings support the idea that under toxicity conditions associated with high LPS doses, VIP and PACAP could act as protective mediators that regulate the excessive release of TNF-alpha to reduce inflammation or shock.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide enhance IL-10 production by murine macrophages: in vitro and in vivo studies

Vasoactive intestinal peptide (VIP), a neuropeptide present in the lymphoid microenvironment, and the structurally related pituitary adenylate cyclase-activating polypeptide (PACAP) act as potent anti-inflammatory agents that inhibit the function of activated macrophages and TH cells. Previous reports showed that VIP/PACAP inhibit IL-6 and TNF-alpha production in LPS-stimulated macrophages. The present study reports on the effect of VIP/PACAP on IL-10 production. Although VIP/PACAP do not induce IL-10 by themselves, they enhance IL-10 production in LPS-stimulated macrophages. The specific VPAC1 receptor mediates the stimulatory effect of VIP/PACAP, and cAMP is the major second messenger involved. VIP/PACAP increase IL-10 mRNA in LPS-stimulated cells, and the effect of transcriptional and protein synthesis inhibitors indicates de novo IL-10 production. Electromobility shift assays show that VIP/PACAP induce an increase in nuclear cAMP response element (CRE)-binding complexes, with CRE binding protein as the major active component. Treatments with either a VPAC1 antagonist or a protein kinase A inhibitor abolish IL-10 stimulation and, concomitantly, the increase in CRE binding. Effects similar to the in vitro stimulation of IL-10 were obtained in vivo in mice treated with LPS and VIP or PACAP. The neuropeptides induce increased levels of IL-10 in both serum and peritoneal fluid, and increased expression of the IL-10 mRNA in peritoneal exudate cells. The stimulation of IL-10 production in activated macrophages represents a novel anti-inflammatory activity of VIP and PACAP, which presumably acts in vivo in conjunction with the inhibition of proinflammatory cytokines such as IL-6 and TNF-alpha to reduce the magnitude of the immune response.

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activation polypeptide (PACAP) protect mice from lethal endotoxemia through the inhibition of TNF-alpha and IL-6

The neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) down-regulate cytokine production. Because human septic shock involves excessive cytokine production, the effect of VIP/PACAP was investigated in a high endotoxemia murine model. Both peptides protect against endotoxin-induced lethality and prevent septic shock-associated histopathological alterations. VIP/PACAP reduce serum and peritoneal TNF-alpha and IL-6, suggesting that the protective effect is exerted by inhibiting the production of endogenous TNF-alpha/IL-6. Consistent with this mechanism, VIP does not protect against septic shock induced by exogenous TNF-alpha. The immunomodulatory role of VIP in vivo is supported by the appearance of high levels of VIP in serum and peritoneal fluid following LPS administration. Thus, the neuropeptides VIP/PACAP protect from the lethal effect of high endotoxemia, presumably by down-regulating TNF-alpha and IL-6 production, and may offer an alternative in the treatment of human septic shock syndrome.

Vasoactive intestinal peptide in thymus: synthesis, receptors and biological actions

Evidence summarized in this report indicates that thymocytes produce and secrete VIP. Moreover, different stimuli such as Con A, LPS and anti-TCR antibody induce a significant increase in VIP production by thymocytes. In addition, proinflammatory cytokines such as IL-1, IL-6 and TNF-alpha, but not IL-2, stimulate in a similar time-dependent manner VIP production by lymphocytes. We also describe the expression of VIP1 receptor and VIP2 receptor mRNA in murine thymocytes. Thus, VIP released in thymus microenvironment may modulate immune functions through direct binding to VIP receptors on thymocytes. Our functional data support that VIP through the interaction with their specific receptors affect three important aspects of thymocytes function: cytokine production, mobility and apoptosis.

Identification of laminin alpha1 and beta1 chain peptides active for endothelial cell adhesion, tube formation, and aortic sprouting

Laminin-1 is a basement membrane glycoprotein that promotes several biological activities including cell attachment, tumor metastasis, and angiogenesis. Angiogenesis plays an important role in tissue formation, reproduction, wound healing, and several pathological conditions. In this study, we screened 405 synthetic peptides from the alpha1 and beta1 chains to identify potential sites on laminin-1 active with endothelial cells. Peptides were initially screened by testing both endothelial cell adhesion to peptide-coated wells and tube formation on Matrigel in the presence of soluble peptide. Twenty active peptides were identified in these screens. A secondary screen using the rat aortic ring sprouting assay identified 13 of the 20 peptides that stimulated endothelial sprouting. Several of these active peptides were also found to stimulate human umbilical vein endothelial cell migration in Boyden chamber assays. Differences in the amount of peptide needed for the response and in the resultant morphologies/responses were observed between the peptides in all of the assays. Our results suggest that several active domains on laminin-1 may play important roles in stimulating different steps in angiogenesis.

Regulation of VIP production and secretion by murine lymphocytes

Vasoactive intestinal peptide (VIP) is a neuropeptide present in the lymphoid microenvironment with a multiplicity of actions. Two sources for VIP have been described in the immune system, the terminals present in central and peripheral lymphoid organs and the immune cells. Although VIP is synthesized by lymphocytes, there is no evidence demonstrating that VIP is released, and which stimuli are able to induce VIP production and secretion. In this study, we demonstrated for the first time, that agents that mediate important immune functions, such as proliferation and antigenic stimulation (Con A, LPS, and anti-TCR antibody), inflammation (LPS, TNFalpha, IL-6 and IL-1beta) or apoptosis (dexamethasone) induce the production and release of VIP to the lymphoid microenvironment. We conclude that VIP is produced and secreted by lymphocytes and propose that during an immune response, the timely release of VIP within the lymphoid organs and peritoneum should influence the differentiation and/or downregulation of the ongoing response.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit tumor necrosis factor alpha transcriptional activation by regulating nuclear factor-kB and cAMP response element-binding protein/c-Jun

Tumor necrosis factor alpha (TNFalpha), an early cytokine produced by activated macrophages, plays an essential role in normal and pathological inflammatory reactions. The excessive production of TNFalpha is prevented by the so-called "macrophage-deactivating factors." This study examines the role of two structurally related neuropeptides, the vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating peptide (PACAP), as inhibitors of TNFalpha. Both VIP and PACAP inhibit TNFalpha production from lipopolysaccharide-stimulated RAW 246.7 cells in a dose- and time-dependent manner. Although the activated cells express mRNA for all three VIP/PACAP receptors, agonist and antagonist studies indicate that the major receptor involved is VIP1R. VIP/PACAP inhibit TNFalpha gene expression by affecting both NF-kB binding and the composition of the cAMP responsive element binding complex (CREB/c-Jun). Two transduction pathways, a cAMP-dependent and a cAMP-independent pathway, are involved in the inhibition of TNFalpha gene expression and appear to differentially regulate the transcriptional factors involved. Because TNFalpha plays a central role in various inflammatory diseases such as endotoxic shock, multiple sclerosis, cerebral malaria, and various autoimmune conditions, the down-regulatory effect of VIP/PACAP may have a significant therapeutic potential.

[Tonsillectomy by electrical dissection versus blunt dissection: a study of 838 cases (Randomized trial of 207 cases and non-randomized prospective study of 631 cases]

Tonsillectomy is one of the most common operations performed in the world and various techniques and instruments have evolved for this purpose. We report the results of two prospective studies: in the first study, blunt dissection was compared with electrodissection tonsillectomy (207 cases), and in the second study, 631 patients had their tonsils removed using only the electrodissection technique. Although electrodissection tonsillectomy is not common in Spain, in our experience it is simple, reliable and easy to learn. Its advantages include minimal bleeding, shorter operating time, and less postoperative hemorrhage. The postoperative morbidity is similar to that of blunt dissection.

Molecular cloning, sequencing, and expression of a chemoreceptor gene from Leptospirillum ferrooxidans

We have cloned and sequenced a 2,262-bp chromosomal DNA fragment from the chemolithoautotrophic acidophilic bacterium Leptospirillum ferrooxidans. This DNA contained an open reading frame for a 577-amino-acid protein showing several characteristics of the bacterial chemoreceptors and, therefore, we named this gene lcrI for Leptospirillum chemotaxis receptor I. This is the first sequence reported for a gene from L. ferrooxidans encoding a protein. The lcrI gene showed both sigma 28-like and sigma 70-like putative promoters. The LcrI deduced protein contained two hydrophobic regions most likely corresponding to the two transmembrane regions present in all of the methyl-accepting chemotaxis proteins (MCPs) which make them fold with both periplasmic and cytoplasmic domains. We have proposed a cytoplasmic domain for LcrI, which also contains the highly conserved domain (HCD region), present in all of the chemotactic receptors, and two probable methylation sites. The in vitro expression of a DNA plasmid containing the 2,262-bp fragment showed the synthesis of a 58-kDa protein which was immunoprecipitated by antibodies against the Tar protein (an MCP from Escherichia coli), confirming some degree of antigenic conservation. In addition, this 58-kDa protein was expressed in E. coli, being associated with its cytoplasmic membrane fraction. It was not possible to determine a chemotactic receptor function for LcrI expressed in E. coli. This was most likely due to the fact that the periplasmic pH of E. coli, which differs by 3 to 4 pH units from that of acidophilic chemolithotrophs, does not allow the right conformation for the LcrI periplasmic domain.

VIP and PACAP enhance IL-6 release and mRNA levels in resting peritoneal macrophages: in vitro and in vivo studies

Vasoactive intestinal peptide (VIP), a neuropeptide produced by lymphocytes has been previously reported to modulate cytokine expression in T lymphocytes. In this study, we investigated the effects of VIP and of the structurally related neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP38) on the production of IL-6 in unstimulated murine peritoneal macrophages. Both neuropeptides stimulate rapidly, specifically, and similarly the production of IL-6, exerting their action through two different receptor/signal transduction systems, i.e., primarily through the binding to VIP1/PACAP receptor followed by adenylate cyclase activation, and partially through the activation of protein kinase C following binding to PACAP-R. VIP and PACAP38 regulate the production of IL-6 at a transcriptional level, affecting the de novo synthesis of this cytokine. The stimulatory in vitro effect correlates with the stimulation of IL-6 expression and release in vivo. These studies suggest that VIP/PACAP play a role in immune system homeostasis, participating in the intricate cytokine network and controlling local immune responses. In addition, the understanding of the factors that regulate the expression and release of IL-6 by macrophages is important for the elucidation of the role of IL-6 in health and disease.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide modulate endotoxin-induced IL-6 production by murine peritoneal macrophages

Vasoactive intestinal peptide (VIP) is a neuropeptide synthesized by immune cells that can modulate several immune aspects, including the function of cells involved in the inflammatory response, such as macrophages and monocytes. Production and release of cytokines by activated mononuclear phagocytes is an important event in the pathogenesis of ischemia-reperfusion injury. VIP has been shown to attenuate the deleterious consequences of this pathologic phenomenon. We have investigated the effects of VIP and PACAP38 on the production of interleukin-6 (IL-6), a proinflammatory cytokine, by endotoxin-activated murine macrophages. Both neuropeptides exhibit a dual effect on the IL-6 production by peritoneal macrophages. Whereas VIP and PACAP inhibit with similar dose-response curves the release of IL-6 from macrophages stimulated with a LPS dose range from 100 pg/mL to 10 microg/mL, both neuropeptides enhance IL-6 secretion in unstimulated macrophages and in macrophages stimulated with very low LPS concentrations (1-10 pg/mL). The inhibition on LPS-induced IL-6 production is specific, presumably mediated through a subtype of the PACAP-R. VIP and PACAP regulate the production of IL-6 at a transcriptional level. These results were correlated with an inhibition on both IL-6 expression and release in endotoxemic mice in vivo. These findings support the idea that in the absence of stimulation or in the presence of low doses of LPS, VIP and PACAP could play a role in immune system homeostasis. However, under toxicity conditions associated with high LPS doses, VIP and PACAP could act as protective mediators that regulate the excessive release of IL-6 in order to reduce inflammation or shock.

Tamoxifen does not improve survival of patients with advanced hepatocellular carcinoma

To discover whether tamoxifen is able to extend the survival of patients with advanced hepatocellular carcinoma, we included 80 patients with cirrhosis and advanced hepatocellular carcinoma in a multicenter, double-blind, placebo-controlled trial in order to analyze the influence of treatment with tamoxifen on survival. The patients were randomized to receive tamoxifen, 40 mg/day (group 1), or placebo (group 2). Both groups were similar in age, sex, etiology of cirrhosis, biochemical, hematologic and hormonal parameters, morphology of the tumor (nodular vs multinodular or massive), Child-Pugh's score, and Okuda's stage. The 1-year survival rate was similar in both groups (30% in group 1 vs 37.8% in group 2; p = 0.31). Tamoxifen treatment was well tolerated by the patients. We conclude that tamoxifen does not extend the survival of patients with cirrhosis and advanced hepatocellular carcinoma.

Compression bandaging effects on lower extremity peripheral and sub-bandage skin blood perfusion

Laser-Doppler blood perfusion was simultaneously measured on both great toes and the lateral upper-calf before and during fore-foot-to-knee compression bandaging of one test-leg in ten vascularly healthy female volunteers. Two bandaging methods were sequentially used separated by a 30 minutes interval. Bandage A consisted of a layer of zinc impregnated gauze and an elastic wrap; bandage B had the elastic wrap only. Sub-bandage pressures of the test-leg were measured at distal and proximal lateral below-knee standardized sites. The study purpose was to determine the effects of moderate compression pressure achieved for bandages A under and distal to bandaged regions. Initial (mean +/- sem_ sub-bandage pressure achieved for bandages A and B were similar, being respectively 32.9 +/- 2.8 and 28.4 +/- 3.9 mm Hg. Both bandages types were associated with significant reductions in test-leg toe blood perfusion amounting to 44.2 +/- 13.1 percent and 27.5 +/- 10.5 percent for bandages A and B respectively. Contrastingly, test-leg sub-bandage blood perfusion did not differ from its pre-bandage baseline mean level for either bandage type. These findings show that a widely used bandaging method and a slight variant each significantly reduces distal (toe) blood perfusion without reducing sub-bandage skin perfusion. Absence of sub-bandage perfusion decreases may be related to a partially compensating reflex vasodilatory response, but such effects if present are inadequate to prevent reductions in distal perfusion. These results reinforce the need for due care and risk-benefit consideration with respect to therapeutic compression levels.

[Thrombosis of the hepatic artery and portal vein secondary to invasive aspergillosis following liver transplantation]

Thrombosis of the main hepatic vessels is a severe, frequent complication in patients requiring liver transplantation. It is usually a cause of emergency retransplantation. Two cases of hepatic vascular thrombosis secondary to disseminated aspergillosis are presented. Both patients demonstrated a septic state and required a second transplantation despite which they died within a few days. Necropsy showed disseminated aspergillosis with invasion of the portal venous system and the hepatic artery. The risk factors associated with this infection and the possible pathogenic mechanisms are discussed.

Gender effect on apolipoprotein E epsilon4 allele-associated risk for sporadic Alzheimer's disease

INTRODUCTION

The role of gender in Alzheimer's disease (AD), and its possible interaction with apolipoprotein E (apoE), has been controversial.

MATERIAL AND METHODS

ApoE allelic frequencies and the effect of apoE epsilon4 allele dosage on risk and age at onset of AD were evaluated, separately for men and women, in 100 patients with sporadic AD and 100 age-matched controls.

RESULTS

The distribution of apoE alleles and the odds ratio for AD, when associated with 1 or 2 epsilon4 alleles, were not statistically different between men and women. No effect of the dosage of the epsilon4 allele was found on the age at onset of dementia in the 2 sex groups.

CONCLUSION

Our data suggest that the relation of the apoE genotype to AD is not dependent on sex.

Functional characterization and mRNA expression of pituitary adenylate cyclase activating polypeptide (PACAP) type I receptors in rat peritoneal macrophages

The present work characterizes the mRNA expression of PACAP type I receptors in rat peritoneal macrophages but not in peritoneal lymphocytes by both retrotranscriptase and polymerase chain reaction (RT-PCR) and homologous Southern hybridization and the stimulation by PACAP27, PACAP38 and vasoactive intestinal peptide (VIP) of sn-1,2-diacylglycerol production in rat peritoneal macrophage membranes. The binding of [125I]PACAP27 was time and cell concentration dependent. Scatchard analysis of displacement of the bound tracer by unlabeled PACAP27 indicates the existence of two classes of binding sites. The dissociation constant (Kd) was 0.64 +/- 0.08 nM and the maximal binding capacity (Bmax) was 8.85 +/- 1.45 fmol/10(6) cells for the high affinity binding site. The low affinity binding site had a Kd of 0.10 +/- 0.06 microM with a Bmax of 300 +/- 21.9 fmol/10(6) cells. Scatchard analysis of VIP displacement data indicated the presence of two classes of binding sites with a Kd and Bmax different to those of PACAP27. These results suggest that PACAP binds to two binding sites, PACAP type I receptors and PACAP type II receptors. The PACAP27-stimulated diacylglycerol production was not affected by treatment with pertussis toxin. However, the presence of GTP partially inhibited this PACAP27 stimulation of 1,2-diacylglycerol in a dose dependent manner, although GTP alone stimulates diacylglycerol accumulation. In conclusion, for the first time we demonstrate by biochemical and molecular biology criteria the existence of PACAP type I receptors on rat peritoneal macrophages and the evidence for coupling with a pertussis toxin-insensitive G regulatory protein.

SUTIL: intelligent ischemia monitoring system

SUTIL is an intelligent monitoring system for intensive and exhaustive follow up of patients in coronary care units. This system processes electrocardiographic and hemodynamic signals in real time, with the main objective of detecting ischemic episodes. In this paper, we describe the tasks included in SUTIL. In addition to basic tasks, those at higher levels will also be presented. Some of these latter tasks attempt to mimic, to some extent, the way in which the human expert operates.

Gene frequencies of the HPA-1 and HPA-2 platelet antigen alleles among the Amerindians

BACKGROUND AND OBJECTIVES

Platelet-specific alloantigens are important in neonatal alloimmune thrombocytopenia, posttransfusion purpura, refractoriness to platelet transfusions, and population genetics. Data are scarce on allele frequencies in ethnic groups other than whites and Asians.

MATERIALS AND METHODS

Using allele-specific restriction enzyme analysis, we studied the distribution of HPA-1 and HPA-2 alleles in six Brazilian Amazon tribes of Amerindians, belonging to five different language stocks. We compared these with the values obtained for blacks and whites.

RESULTS

Only the HPA-1a allele was found among 132 Amerindian chromosomes, compared with a gene frequency of HPA-1b of 0.115 and 0.113, respectively, among blacks and whites. The frequency of HPA-2b among the Amerindians (0.042) is lower than that obtained for blacks and whites (0.148 and 0.100, respectively), and the lowest thus far observed in a population of Asian origin.

CONCLUSION

Differences in DNA polymorphisms in Amerindian populations have not only anthropological and genetic interest, but also practical applications when they involve coding regions that may change the functional or immunologic features of the protein.

Making the case for culturally appropriate community services: Puerto Rican elders and their caregivers

This study of the caregiving arrangements of 214 disabled elderly people in a large northeastern city found that the recipients of care were severely disabled, particularly in instrumental activities of daily living, yet had limited sources of informal care and used formal services minimally. The authors discuss the need to use a structural adaptation approach and to develop social services that are culturally sensitive and acceptable to both elders and their caregivers.

Variability in skin microvascular vasodilatory responses assessed by laser-Doppler imaging

Skin blood perfusion (SBP) responses to pressure loading and other traumatic and noxious stimuli are used to help identify patients at-risk of skin breakdown, evaluate preventive strategies and help clarify patho-physiological mechanisms in pre-ulcerative and ulcerative conditions. Often, laser-Doppler methods are used to compare vasodilatory responses at differing skin sites to evaluate skin parameter changes. Significant variations in skin microvasculature are known to be normally present, even in closely separated skin zones. In this study, spatial variability and temporal responses of SBP were evaluated with a widely used topical vasodilator (methylnicotinate, MN). A mask with nine holes (1.25 cm2 each) was placed on the volar forearm of ten volunteers. SBP was measured with laser-Doppler Imaging (LDI) prior to applying MN (15 ul, 50 mM) to six zones and 5, 10, 15, 20 and 30 minutes afterwards. Inter-zone mean SBP and inter- and intra-zone coefficients of variation (CV) were determined at each time. Results show that MN responses, when determined as zone LDI means, reached maximum at 15 minutes with no significant differences in relative responses among treated zones. Inter-zone perfusion CV's (range 0.11-0.13) were about 50 percent of intra-zone CV's (p < 0.01). We conclude that LDI perfusion responses can be obtained at different forearm skin sites with reasonable and acceptable levels of spatial variation if zone mean SBP values are used.

[The clinical importance of bacteremia during tonsillectomy]

INTRODUCTION

Post-tonsillectomy bacteraemia is a well recognized aetiological factor in streptococcal endocarditis. Prophylactic penicillin has been recommended to reduce its incidence in susceptible patients undergoing tonsillectomy. Recent studies have shown a change in the microflora and an increase in the number of penicillin-resistant organisms in the tonsils of patients undergoing tonsillectomy.

OBJECTIVE

The aim of this study was to assess the incidence of post-tonsillectomy bacteraemia, identify the associated organisms, and review the suitability of penicillin in prophylactic regimens.

MATERIAL AND METHODS

102 children were included. Blood culture samples were taken after removal of the first tonsil, which was randomly electrodissected or blunt dissected. Statistical analysis was performed using ANOVA.

RESULTS

Of the 102 patients included in the study, 41 (40.1%) had positive post-tonsillectomy blood cultures. Haemophilus influenzae was isolated from 23 (56%) of the positive cultures and Streptococcus viridans from 15 (36.5%). Twenty-five percent of H. influenzae and 50% of the viridans group produced beta-lactamase.

CONCLUSIONS

A beta-lactamase stable antibiotic would be more appropriate than penicillin for prophylaxis during tonsillectomy.

Heel blood perfusion responses to pressure loading and unloading in women

Heel pressure ulcers are significant and costly problems causing suffering and potential limb loss from infection and compromised blood flow. Heel blood perfusion (HBP) deficits accompanying loading likely affect the skin breakdown process, but little is known about the loading and off-loading changes. To clarify this issue, combined laser-Doppler Imaging (LDI) and Fluxmetry were used to assess HBP before, during, and after 40 minutes of continuous heel loading in 11 female volunteers (32-60 years). During loading, an initial decrease in HBP was followed by a gradual small recovery (p < 0.001). Off-loading resulted in a significant hyperemic response with HBP exceeding baseline by a factor of 4.72 +/- 0.63 (p = 0.001) and remaining elevated for about 10 minutes. Spatial LDI data showed that hyperemic responses are maximum near the pressure center and diminish radially. These results suggest a localized, pressure-related tissue trauma, which is compensated for by a substantial hyperperfusion. The dependence (and adequacy) of this response on clinical variables including heel pressure and duration, limb vascular status, and patient health are unknown. The present seminal data and associated methods provide a platform from which these and other important clinical parameters can be systematically studied and compared.