Biomedical subjects

P Alm

Publications and source records attributed to P Alm.

At least 19 recordsLinked to original sources

PubMed2006

Intracerebral administration of neuronal nitric oxide synthase antiserum attenuates traumatic brain injury-induced blood-brain barrier permeability, brain edema formation, and sensory motor disturbances in the rat.

The role of nitric oxide (NO) in traumatic brain injury (TBI)-induced sensory motor function and brain pathology was examined using intracerebral administration of neuronal nitric oxide synthase (nNOS) antiserum in a rat model. TBI was produced by a making a longitudinal incision into the right parietal cerebral cortex limited to the dorsal surface of the hippocampus. Focal TBI induces profound edematous swelling, extravasation of Evans blue dye, and up-regulation of nNOS in the injured cerebral cortex and the underlying subcortical areas at 5 hours. The traumatized animals exhibited pronounced sensory motor deficit, as seen using Rota-Rod and grid-walking tests. Intracerebral administration of nNOS antiserum (1 : 20) 5 minutes and 1 hour after TBI significantly attenuated brain edema formation, Evans blue leakage, and nNOS expression in the injured cortex and the underlying subcortical regions. The nNOS antiserum-treated rats showed improved sensory motor functions. However, administration of nNOS antiserum 2 hours after TBI did not influence these parameters significantly. These novel observations suggest that NO participates in blood-brain barrier disruption, edema formation, and sensory motor disturbances in the early phase of TBI, and that nNOS antiserum has some potential therapeutic value requiring additional investigation.

Animals↗

PubMed2006

Topical application of dynorphin A (1-17) antibodies attenuates neuronal nitric oxide synthase up-regulation, edema formation, and cell injury following focal trauma to the rat spinal cord.

Previous investigations from our laboratory show that up-regulation of neuronal nitric oxide synthase (NOS) following spinal cord injury (SCI) is injurious to the cord. Antiserum to dynorphin A (1-17) induces marked neuroprotection in our model of SCI, indicating an interaction between dynorphin and NOS regulation. The present investigation was undertaken to find out whether topical application of dynorphin A (1-17) antiserum has some influence on neuronal NOS up-regulation in the traumatized spinal cord. SCI was produced in anesthetized animals by making a unilateral incision into the right dorsal horn of the T10-11 segments. The antiserum to dynorphin A (1-17) was applied (1 : 20, 20 microL in 10 seconds) 5 minutes after trauma over the injured spinal cord and the rats were allowed to survive 5 hours after SCI. Topical application of dynorphin A (1-17) antiserum significantly attenuated neuronal NOS up-regulation in the adjacent T9 and T12 segments. In the antiserum-treated group, spinal cord edema and cell injury were also less marked. These observations provide new evidence that the opioid active peptide dynorphin A may be involved in the mechanisms underlying NOS regulation in the spinal cord after injury, and confirms our hypothesis that up-regulation of neuronal NOS is injurious to the cord.

Animals↗

PubMed2004

The early ontogeny of neuronal nitric oxide synthase systems in the zebrafish.

To examine a putative role for neuronal nitric oxide synthase (nNOS) in early vertebrate development we investigated nNOS mRNA expression and cGMP production during development of the zebrafish Danio rerio. The nNOS mRNA expression in the central nervous system (CNS) and periphery showed a distinct spatio-temporal pattern in developing zebrafish embryo and young larvae. nNOS mRNA expression was first detected at 19 h postfertilisation (h.p.f.), in a bilateral subpopulation of the embryonic ventrorostral cell cluster in the forebrain. The number of nNOS mRNA-expressing cells in the brain slowly increased, also appearing in the ventrocaudal cell cluster from about 26 h.p.f., and in the dorsorostral and hindbrain cell cluster and in the medulla at 30 h.p.f. A major increase in nNOS mRNA expression started at about 40 h.p.f., and by 55 h.p.f. the expression constituted cell populations in differentiated central nuclei and in association with the proliferation zones of the brain, and in the medulla and retina. In parts of the skin, nNOS mRNA expression started at 20 h.p.f. and ended at 55 h.p.f. Between 40 and 55 h.p.f., nNOS mRNA expression started in peripheral organs, forming distinct populations after hatching within or in the vicinity of the presumptive swim bladder, enteric ganglia, and along the alimentary tract and nephritic ducts. Expression of nNOS mRNA correlated with the neuronal differentiation pattern and with the timing and degree of cGMP production. These studies indicate spatio-temporal actions by NO during embryogenesis in the formation of the central and peripheral nervous system, with possible involvement in processes such as neurogenesis, organogenesis and early physiology.

Animals↗

PubMed2003

Topical application of TNF-alpha antiserum attenuates spinal cord trauma induced edema formation, microvascular permeability disturbances and cell injury in the rat.

The possibility that antiserum to tumour necrosis factor-alpha (TNF-alpha) is neuroprotective in spinal cord injury (SCI) was examined in a rat model. SCI was produced by making an incision into the right dorsal horn at the T10-11 segments. Top TNF-alpha antiserum at three concentrations (1:10; 1:50 and 1:100) given 30 min before or 2 min, 5 min or 10 min after trauma resulted in marked reduction in visible swelling, edema formation, and leakage of radiolabelled iodine tracer within the T9 and T12 segments at 5 h in a dose dependent manner. This neuroprotective effect was most pronounced when the antiserum at the highest dose level (1:10) was applied 10 min after SCI. The TNF-alpha antiserum also reduced the SCI induced upregulation of neuronal nitric oxide synthase (nNOS) immunoreactivity in a concentration dependent manner. Taken together, these results suggest that local application of TNF-alpha antiserum is neuroprotective in SCI and that this effect is mediated through NOS regulation.

Administration, Topical↗

PubMed2003

A new antioxidant compound H-290151 attenuates spinal cord injury induced expression of constitutive and inducible isoforms of nitric oxide synthase and edema formation in the rat.

The role of oxidative stress in spinal cord injury (SCI) induced upregulation of constitutive or inducible isoforms of nitric oxide synthase (cNOS or iNOS) is not well known. The present investigation was undertaken to examine the influence of an antioxidant compound H-290/51 (Astra-Zeneca, Mölndal, Sweden) on SCI induced cNOS and iNOS upregulation in a rat model. SCI induced by incision into the right dorsal horn of the T10-11 segment resulted in marked NOS upregulation. Upregulation of cNOS was most prominent in the uninjured T9 and T12 segments. On the other hand, iNOS expression was most marked in the injured T10-11 segments. These NOS immunoreactivities were mainly confined to the injured cells located in the edematous regions of the cord exhibiting profound leakage of Evans blue and [131]Iodine-sodium tracers. Pre-treatment with H-290/51 markedly attenuated the trauma-induced cNOS and iNOS expression along with the microvascular permeability disturbances, edema formation and cell injury. These results suggest that (i) oxidative stress is involved in SCI induced induction of cNOS and iNOS, (ii) NO plays an important role in the cord pathology, and (iii) that the compound H-290/51 has a potential therapeutic value in SCI.

Animals↗

PubMed2002

Male gynecomastia and risk for malignant tumours--a cohort study.

BACKGROUND: Men with gynecomastia may suffer from absolute or relative estrogen excess and their risk of different malignancies may be increased. We tested whether men with gynecomastia were at greater risk of developing cancer. METHODS: A cohort was formed of all the men having a histopathological diagnosis of gynecomastia at the Department of Pathology, University of Lund, following an operation for either uni- or bilateral breast enlargement between 1970-1979. All possible causes of gynecomastia were accepted, such as endogenous or exogenous hormonal exposure as well as cases of unknown etiology. Prior to diagnosis of gynecomastia eight men had a diagnosis of prostate carcinoma, two men a diagnosis of unilateral breast cancer and one had Hodgkin's disease. These patients were included in the analyses. The final cohort of 446 men was matched to the Swedish Cancer Registry, Death Registry and General Population Registry. RESULTS: At the end of the follow up in December 1999, the cohort constituted 8375.2 person years of follow-up time. A total of 68 malignancies versus 66.07 expected were observed; SIR = 1.03 (95% CI 0.80-1.30). A significantly increased risk for testicular cancer; SIR = 5.82 (95% CI 1.20-17.00) and squamous cell carcinoma of the skin; SIR = 3.21 (95% CI 1.71-5.48) were noted. The increased risk appeared after 2 years of follow-up. A non-significantly increased risk for esophageal cancer was also seen while no new cases of male breast cancer were observed. However, in the prospective cohort, diagnostic operations for gynecomastia may substantially have reduced this risk CONCLUSIONS: There is a significant increased risk of testicular cancer and squamous cell carcinoma of the skin in men who have been operated on for gynecomastia.

Adolescent↗

PubMed2002

Nitric oxide synthase inhibitors influence dynorphin A (1-17) immunoreactivity in the rat brain following hyperthermia.

The possibility that nitric oxide synthase (NOS) inhibitors influence dynorphin immunoreactivity following hyperthermia was examined in a rat model using a pharmacological approach. Previous reports from our laboratory show that hyperthermia induces an upregulation of NOS in several brain regions that seems to be instrumental in causing cell injury. Recent reports suggest that nitric oxide (NO) can influence dynorphin neurotransmission in the normal brain as well as in several pathological states. Since dynorphin is neurotoxic in different animal models of brain or spinal cord injury, it may be that the peptide will contribute to the cell injury in hyperthermia. The present investigation was carried out to determine whether hyperthermia can influence dynorphin immunoreactivity in the brain, and if so, whether inhibition of NOS will influence the peptide distribution in the brain following heat stress. Rats subjected to hyperthermia at 38 degrees C for 4 h in a biological oxygen demand incubator (BOD) resulted in a marked upregulation of dynorphin immunoreactivity in several brain regions e.g., cerebral cortex, hippocampus, cerebellum and brain stem. Pretreatment of rats with two potent NOS inhibitors, L-NAME (30 mg/kg/day, i.p. for 7 days) or L-NMMA (35 mg/kg/day, i.p. for 7 days) significantly attenuated the dynorphin immunoreactivity in the brain. These drugs were also able to reduce hyperthermia induced blood-brain barrier (BBB) permeability, brain edema formation and cell injury. Taken together, our results suggest that (i). hyperthermia has the capacity to upregulate dynorphin immunoreactivity in the brain, (ii). inhibition of NOS considerably attenuates the dynorphin immunoreaction following heat stress and (iii). upregulation of dynorphin is somehow contributing to hyperthermia induced brain damage, not reported earlier.

Animals↗

PubMed2002

Morphological and functional characterization of a rat vaginal smooth muscle sphincter.

The aim of the present study was to gain information about adrenergic-, cholinergic- and non-adrenergic, non-cholinergic (NANC)- transmitter systems/mediators in the rat vagina, and to characterize its smooth muscles functionally. Tissue sections from vagina of Sprague Dawley rats were immunolabelled with antibodies against protein gene product 9.5 (PGP), synaptophysin (Syn), tyrosine hydroxylase (TH), vesicular acetylcholine transporter (VAChT), neuropeptide Y (NPY), nitric oxide synthase (NOS), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP). Circularly cut vaginal smooth muscle preparations from the distal vagina were studied in organ baths. In the paravaginal tissue, a large number of PGP-, NOS-, TH-, VIP-immunoreactive (IR) and few CGRP-IR nerve trunks were observed, giving off branches to the smooth muscle wall. The smooth muscle wall was supplied by a large number of PGP-, Syn-, VAChT-, NPY-, NOS- and TH- IR nerve terminals, whilst only a moderate to few numbers of CGRP-, VIP- and PACAP-IR terminals were identified. Especially the distal part of the vaginal wall, where the circularly running smooth muscle was thickened into a distinct sphincter structure, was very richly innervated, predominantly by PGP- and NOS-IR terminals. Below and within the basal parts of the epithelium in the distal half of the vagina, a large number of PGP- and few NOS- and PACAP-IR varicose terminals were observed. The vaginal arteries were encircled by plexuses of nerve terminals. A large number of these were PGP-, Syn-, VAChT-, NOS-, TH-, NPY- and VIP-IR, and few were CGRP- and PACAP-IR. In isolated preparations of the distal vagina, electrical field stimulation (EFS) caused frequency-dependent contractions, which were reduced by sildenafil, tetrodotoxin (TTX) and phentolamine. In preparations contracted by norepinephrine (NA), EFS produced frequency-dependent relaxations. Pretreatment with the NOS-inhibitor N(G)-nitro-L-arginine, TTX, or the inhibitor of soluble guanylate cyclase, ODQ, abolished the EFS relaxations. In NE precontracted preparations, cumulative addition of sildenafil caused concentration-dependent relaxation. Carbachol contracted the strips concentration-dependently from baseline. It can be concluded that the distal part of the rat vagina forms a distinct smooth muscle sphincter, which is richly innervated by adrenergic, cholinergic and NANC nerves. The present studies suggest that in the rat the L-arginine/NO-system not only plays an important role in the regulation of vaginal smooth muscle tone, but also affects blood flow, and may have sensory functions.

Acetylcholinesterase↗

PubMed2001

Nitric oxide synthase in the hypothalamic paraventricular nucleus of the female rat; organization of spinal projections and coexistence with oxytocin or vasopressin.

We investigated the distributions and interrelations of neuronal nitric oxide (NO) synthase- (nNOS), oxytocin- (OT), and 8-arginine vasopressin- (AVP) immunoreactive (IR) neurons in the paraventricular nucleus (PVN), and the occurrence and distribution of nNOS spinally projecting neurons in the PVN of the female rat. Using double labelling immunohistochemistry, we mapped the distribution of nNOS-, OT- and AVP-immunoreactive (IR) neuronal cell bodies in the different parts of the PVN. About 80% of nNOS-IR cell bodies were magnocellular. About 30% of the nNOS-IR cell bodies were OT-IR, colocalization being most frequent in the rostral parts. In comparison, only approximately 3% of all nNOS-IR cell bodies were AVP-IR, evenly distributed throughout the PVN. True Blue (TB), administered unilaterally into the spinal cord, disclosed that most spinally projecting cell bodies in the PVN were localized in caudal parts. Combined TB tracing and nNOS immunohistochemistry showed that approximately 30% of spinally projecting neurons in the PVN were nNOS-IR, and that approximately 40% of these were magnocellular. Ipsilateral nNOS spinal projections were about eight times more frequent than the contralateral nNOS projections. The study describes the detailed neuroanatomical organization of nNOS neurons coexpressing OT or AVP, and of nNOS spinally projecting neurons within defined parts of the PVN. In contrast to the paraventriculo-spinal system in general, we show that the nNOS paraventriculo-spinal pathway to a large extent originates in magnocellular cell bodies. The results suggest that NO is an important messenger in the paraventriculo-spinal pathway that may in part act in concert with OT.

Animals↗

PubMed2001

Neuroendocrine cells and nerves in the prostate of the guinea pig: effects of peripheral denervation and castration.

BACKGROUND: Neuroendocrine (NE) cells and nerves in the prostate gland are thought to play a central role in the regulation of growth, cellular differentiation and homeostasis of secretory activity. The objective of this experimental study was to describe the effects of peripheral denervation and castration on NE cells and nerves in the guinea pig prostate. METHODS: Guinea pigs underwent sham-operation, unilateral and bilateral hypogastric nerve resection, extirpation of the right anterior major pelvic ganglion (AMPG), autotransplantation of prostatic tissue and castration. Cryostat sections of prostatic tissue were examined with immunohistochemistry by using serotonin (5-HT) and chromogranin A (CgA) and various neuropeptides. RESULTS: The number of 5-HT-IR NE cells was four-fold higher than CgA-IR NE cells. The innervation pattern was uniform throughout the gland with subepithelial nerves in close proximity to NE cells. Autotransplants of prostatic tissue showed total loss of nerves, but the number and morphology of 5-HT-IR NE cells were unaltered. Extirpation of the right AMPG showed significant reduction in prostate weight, decreased density of nerve terminals in the superior part of the ipsilateral prostate, whereas the number and morphological feature of 5-HT-IR NE cells remained unaffected in the entire prostate. Castration induced atrophy of the gland with a significant reduction in weight (unpaired t-test, P < 0.001), but without effect upon 5-HT-IR NE cells. CONCLUSIONS: The guinea pig seems to be a useful animal model for studies on the role of the NE cells in the prostate. NE cells seem to be independent of innervation and androgens. It seems that other factors influence the NE cell population to a greater extent.

Animals↗

PubMed2001

Detailed organization of nitric oxide synthase, vasopressin and oxytocin immunoreactive cell bodies in the supraoptic nucleus of the female rat.

The anatomical distribution and quantitative relations of cell bodies containing neuronal nitric oxide synthase (nNOS), 8-arginine vasopressin (AVP) and oxytocin (OT) were examined throughout the supraoptic nucleus (SON) of the female rat by means of immunocytochemical and NADPH-diaphorase (NADPH-d) histochemical techniques using a triple labelling methodology. Seven chemically defined populations of neurons containing all combinations of either nNOS, AVP or OT were identified. nNOS-containing (NADPH-d positive) neurons, amounting to about 40% of all neurons counted, were most frequent in central and dorsal regions, and were evenly distributed along the rostro-caudal axis. Two small nNOS-positive neuronal populations were preferentially located dorso-centrally in the nucleus: nNOS-positive neurons containing both AVP- and OT-immunoreactivity, and neurons only containing nNOS. Slightly less than half of all nNOS-positive neurons contained AVP, and a similar share of nNOS-positive neurons contained OT. The occurrence of nNOS-positive/AVP-containing neurons was highest in the caudal half, whereas that of nNOS-positive/OT-neurons was highest in the rostral half of SON. The data demonstrate new findings concerning the anatomical organization and co-localization patterns of nNOS-, AVP- and OT-containing neuronal populations in SON. We conclude that the absolute and relative occurrence of the identified neuronal populations vary markedly in different parts of SON. This is important to take into consideration when performing, and evaluating experimental investigations concerned with neurochemical changes in SON.

Animals↗

PubMed2001

Morphological and functional in vitro and in vivo characterization of the mouse corpus cavernosum.

1. In normal mice, the distribution of adrenergic, cholinergic, some peptidergic, and neuronal nitric oxide synthase (nNOS)-containing nerves were investigated. Functional in vitro correlates were obtained. An in vivo model was developed in which erectile haemodynamics in response to drugs or nerve-stimulation were studied. 2. Immunoreactivities for vesicular acetylcholine transporter protein (VAChT), nNOS-, and vasoactive intestinal polypeptide (VIP), co-existed in nerve fibres and terminal varicosities. Immunoreactivities for neuropeptide Y (NPY) and tyrosine hydroxylase (TH) were found in the same nerve structures. 3. Chemical sympathectomy abolished TH- and NPY-IR nerve structures in cavernous smooth muscle bundles. The distribution of calcitonin gene-related peptide (CGRP)-, nNOS-, VAChT- and VIP-IR nerve structures was unchanged. 4. In endothelial cells of the central and helicine arteries, veins and venules, intense immunoreactivity for endothelial NOS (eNOS) was observed. No distinct eNOS-IR cells were found lining the cavernous sinusoids. 5. In vitro, nerve-induced relaxations were verified, and endothelial NO/cyclic GMP-mediated relaxant responses were established. VIP and CGRP had small relaxant effects. A functioning adenylate cyclase/cyclic AMP pathway was confirmed. 6. Neuronal excitatory responses were abolished by prazosin, or forskolin. VIP and CGRP counteracted contractions, whereas NPY and scopolamine enhanced excitatory responses. 7. In vivo, erectile responses were significantly attenuated by L-NAME (50 mg kg(-1)) and facilitated by sildenafil (200 microg kg(-1)). 8. It is concluded that the mouse is a suitable model for studies of erectile mechanisms in vitro and in vivo.

Animals↗

PubMed2001

Effects of diabetes on neurotransmission in rat vaginal smooth muscle.

The aim of this work was to characterize the effect of experimental diabetes on neurotransmission in rat vagina. Female Sprague-Dawley rats were divided into two groups: non-diabetic controls (NDM, n=38) and diabetics (DM, n=38). DM was produced by intraperitoneal injection of streptozotocin. Eight weeks later the animals were killed, the distal part of the vagina was removed, and smooth muscle strips were prepared for functional organ bath experiments and for measurement of nitric oxide synthase (NOS) activity. In DM preparations, the EC(50) value for noradrenaline (NA) was significantly increased (P<0.05) and the maximal contractile response decreased (P=0.001). In preparations precontracted with NA, the NO donor SNAP and calcitonin gene-related peptide (CGRP) caused concentration-dependent relaxations, which were significantly decreased (P<0.001) in the DM group. Electrical stimulation of nerves (EFS) caused frequency-dependent contractions, which were significantly lower in DM than in NDM strips (P<0.001). SNAP and CGRP concentration-dependently inhibited EFS evoked contractions in both NDM and DM preparations. The inhibition was significantly lower (P<0.05) in the DM group. In NDM preparations precontracted with NA, EFS evoked frequency-dependent relaxations; such relaxations were inhibited or reduced in DM. Treatment with the NOS inhibitor, L-NOARG 0.1 mM, abolished relaxations in all preparations or produced contraction in DM preparations. Calcium-dependent NOS activity was not significantly different in the DM and NDM groups. However, the DM animals showed a small but significant increase in calcium-independent NOS-activity (P<0.05). Diabetes interferes with adrenergic-, cholinergic- and NANC-neurotransmitter mechanisms in the smooth muscle of the rat vagina. The changes in the nitrergic neurotransmission are not due to reduction in NOS-activity, but seem to be due to interference with later steps in the L-arginine/NO/guanylate cyclase/cGMP system.

Animals↗

PubMed2001

Correlation between the expression of DNA topoisomerases I and IIalpha and clinical parameters in kidney disease.

Multiple factors interact during the evolution of renal diseases. In the present study, we examined the expression of DNA topoisomerases type I and IIalpha, which reflect gene transcription and DNA replication, respectively. Enzyme content was assessed by immunohistochemistry using two specific monoclonal antibodies, C21 and Ki-S4, on 81 archival punch-biopsy specimens from patients with renal diseases, including minimal change disease (MCD; n = 10), focal segmental glomerular sclerosis (FSGS; n = 6), mesangial proliferative glomerulonephritis (MPGN; n = 11), membranous glomerulonephritis (MGN; n = 10), mesangial capillary glomerulonephritis (MCGN; n = 7), rapidly progressive glomerulonephritis (RPGN; n = 12), lupus nephritis (LN; n = 15), and tubulointerstitial nephritis (TIN; n = 10). Both enzymes were strongly expressed in diseases tending to rapid progression, notably RPGN and LN, whereas MCD and MGN showed low protein levels in both the glomerular and tubular compartments. Moreover, topoisomerase expression was significantly associated with the density of monocytogenic infiltrates (monitored by means of the monoclonal antibody Ki-M1p), such pathogenesis-associated factors as antinuclear antibodies and paranuclear antineutrophilic antibodies, and serum immunoglobulin levels. There also was a positive correlation with serum creatinine levels and an inverse association with proteinuria and nephrotic syndrome. We conclude that the expression of DNA topoisomerases may be linked to pathogenetic mechanisms and may provide prognostic information. Because of their comparatively low nephrotoxicity, topoisomerase inhibitors might prove to be useful therapeutic agents in the treatment of renal diseases.

Adult↗

PubMed2001

Concurrent overexpression of p53 and c-erbB-2 correlates with accelerated cycling and concomitant poor prognosis in node-negative breast cancer.

Simultaneous overexpression of c-erbB-2 and p53 has been reported to be prognostically unfavorable in breast cancer. Herein, we show that concurrent overexpression of these 2 proteins is associated with a marked reduction in the relative fraction of cells in G(1) phase of the cell cycle, indicating an accelerated cell cycle progression. Using an immunohistochemical approach, we examined 261 cases of node-negative infiltrating ductal carcinomas of the breast with respect to c-erbB-2 and p53 expression and to the proliferative activity measured by the Ki-67 index. By means of a novel monoclonal antibody, Ki-S2, which exclusively recognizes proliferating cells in the S, G(2), and M phases of the reproductive cycle, we were further able to calculate the relative fraction of the cells having passed the restriction point at the G(1)/S boundary, thus defining a cycling ratio (CR). The results were correlated with clinical outcome; median follow-up time was 96 months. Tumors that simultaneously overexpressed c-erbB-2 and p53 had a high median CR and followed an unfavorable course. However, increased CRs were also observed independently of c-erbB-2 and p53 overexpression, suggesting that other molecular mechanisms may contribute to acceleration of cell cycle progression. In a multivariate analysis that included patient age, tumor size, hormone receptor status, c-erbB-2 and p53 expression, and the Ki-67 index, CR emerged as the most significant independent predictor of overall and disease-free survival (P <.0001). It is concluded that the CR is a gauge of cell cycle deregulation and therefore may be a powerful indicator of the biologic behavior of cancers. HUM PATHOL 32:311-319.

Adult↗

PubMed2001

Evaluation of islet heme oxygenase-CO and nitric oxide synthase-NO pathways during acute endotoxemia.

We investigated, by a combined in vivo and in vitro approach, the temporal changes of islet nitric oxide synthase (NOS)-derived nitric oxide (NO) and heme oxygenase (HO)-derived carbon monoxide (CO) production in relation to insulin and glucagon secretion during acute endotoxemia induced by lipopolysaccharide (LPS) in mice. Basal plasma glucagon, islet cAMP and cGMP content after in vitro incubation, the insulin response to glucose in vivo and in vitro, and the insulin and glucagon responses to the adenylate cyclase activator forskolin were greatly increased after LPS. Immunoblots demonstrated expression of inducible NOS (iNOS), inducible HO (HO-1), and an increased expression of constitutive HO (HO-2) in islet tissue. Immunocytochemistry revealed a marked expression of iNOS in many beta-cells, but only in single alpha-cells after LPS. Moreover, biochemical analysis showed a time dependent and markedly increased production of NO and CO in these islets. Addition of a NOS inhibitor to such islets evoked a marked potentiation of glucose-stimulated insulin release. Finally, after incubation in vitro, a marked suppression of NO production by both exogenous CO and glucagon was observed in control islets. This effect occurred independently of a concomitant inhibition of guanylyl cyclase. We suggest that the impairing effect of increased production of islet NO on insulin secretion during acute endotoxemia is antagonized by increased activities of the islet cAMP and HO-CO systems, constituting important compensatory mechanisms against the noxious and diabetogenic actions of NO in endocrine pancreas.

Animals↗

PubMed2000

Severe lung lesions caused by Salmonella are prevented by inhibition of the contact system.

Vascular damage induced by trauma, inflammation, or infection results in an alteration of the endothelium from a nonactivated to a procoagulant, vasoconstrictive, and proinflammatory state, and can lead to life-threatening complications. Here we report that activation of the contact system by Salmonella leads to massive infiltration of red blood cells and fibrin deposition in the lungs of infected rats. These pulmonary lesions were prevented when the infected animals were treated with H-D-Pro-Phe-Arg-chloromethylketone, an inhibitor of coagulation factor XII and plasma kallikrein, suggesting that inhibition of contact system activation could be used therapeutically in severe infectious disease.

Amino Acid Chloromethyl Ketones↗

PubMed2000

CGMP increases in satellite cells of nitric oxide synthase-containing sensory ganglia.

cGMP and the enzymes, nitric oxide synthase (NOS) and heme oxygenase-1 (HO-1), the products of which stimulate soluble guanylyl cyclase activity, were investigated in cultured dorsal root ganglia (DRG), and nodose ganglia of adult rats. A dramatic increase of cGMP-positive satellite cells in ganglia cultured for 24 or 48 h was observed, particularly in Th8-L2 DRG and in nodose ganglia. These ganglia also contained most NOS-positive neurones, as reflected by NADPH-diaphorase histochemistry. HO-1 immunoreactivity increased in satellite cells, but in different cells to those in which cGMP increased. These results suggest that both NO and CO could be involved in signalling between neurones and satellite cells in sensory ganglia during regeneration.

Animals↗