Delta-opioid receptor-immunoreactive neurons in the rat cranial sensory ganglia

Immunohistochemistry for delta-opioid receptor (DOR) was performed on the rat cranial sensory ganglia. The immunoreactivity was detected in 16%, 19% and 11% of neurons in the trigeminal, jugular and petrosal ganglia, respectively. The nodose ganglion was devoid of such neurons. DOR-immunoreactive (IR) neurons were mostly small to medium-sized (trigeminal, range = 62-851 microm(2), mean +/- SD = 359 +/- 175 microm(2); jugular, range = 120-854 microm(2), mean +/- SD = 409 +/- 196 microm(2); petrosal, range = 167-1146 microm(2), mean +/- SD = 423 +/- 233 microm(2)). Double immunofluorescence method revealed that all DOR-IR neurons were also immunoreactive for calcitonin gene-related peptide. The cutaneous and mucosal epithelia in the oro-facial region, tooth pulp, taste bud and carotid body were innervated by DOR-IR nerve fibers. In the brainstem, IR nerve terminals were located in the superficial medullary dorsal horn and dorsomedial part of the subnucleus oralis as well as the solitary tract nucleus. The present study suggests that DOR-IR neurons may be associated with nociceptive and/or chemoreceptive function in the cranial sensory ganglia.

Effect of Brn-3a deficiency on primary nociceptors in the trigeminal ganglion

Immunohistochemistry for substance P, somatostatin and vanilloid receptor subtype 1 as well as receptors for somatostatin and opioids was performed on the trigeminal ganglion in wild-type and Brn-3a knockout mice at postnatal day 0. In wild-type mice, the trigeminal ganglion contained abundant substance P-, vanilloid receptor subtype 1-, sst2A receptor- and delta-opioid receptor-immunoreactive neurons, while the ganglion had only a few mu-opioid receptor-immunoreactive neurons. The Brn-3a deficiency had an effect on the cell size but not the number of substance P-immunoreactive neurons. In knockout mice, the proportion of small immunoreactive neurons markedly increased and that of medium- to large-sized immunoreactive ones correspondingly decreased (mean +/- S.D. = 54.7 +/- 29.1 microm2, range = 10.9-220.8 microm2) compared to wild-type mice (mean +/- S.D. = 116.6 +/- 58.6 microm2, range = 27.3-400.7 microm2). As for vanilloid receptor subtype 1-immunoreactive neurons, the number and cell size was barely affected by the deficiency. On the other hand, the loss of Brn-3a caused a decrease in the number of sst2A receptor- or delta-opioid receptor-immunoreactive neurons (more than 95% reduction) and an increase in the number of mu-opioid receptor-immunoreactive neurons (9.3-fold increase). Somatostatin-immunoreactive neurons were not detected in the trigeminal ganglion of wild-type or mutant mice at postnatal day 0. The present study suggests that Brn-3a deficiency may have effects on the survival of trigeminal nociceptors and their expression of some neurochemical substances.

Osteocalcin-immunoreactive neurons in the vagal and glossopharyngeal sensory ganglia of the rat

Immunohistochemistry for osteocalcin (OC) was performed on the rat vagal and glossopharyngeal sensory ganglia. OC-immunoreactive (IR) neurons were detected in the jugular (10%), petrosal (11%) and nodose ganglia (6%). The cell size analysis demonstrated that OC-IR neurons were predominantly small to medium-sized in the jugular ganglion (mean+/-S.D.=356.3+/-192.2 microm(2), range=86.5-831.5 microm(2)). On the other hand, such neurons were medium-sized to large in the petrosal (mean+/-S.D.=725.6+/-280.7 microm(2), range=124.7-1540.4 microm(2)) and nodose ganglia (mean+/-S.D.=857.5+/-330.2 microm(2), range=367.1-1608.0 microm(2)). In the circumvallate papilla, OC-IR nerve fibers were located in the vicinity of taste buds. Some taste bud cells were also immunoreactive for the calcium-binding protein (CaBP). In the carotid body, however, OC-IR nerve fibers could not be detected. Retrograde tracing with fluorogold revealed that OC-IR nerve fibers in the circumvallate papilla mainly originated from the petrosal ganglion. These findings may suggest that OC-IR petrosal neurons have chemoreceptive function in the tongue.

Role of endothelial mitochondria in oxidant production and modulation of neutrophil adherence

This study is designed to test whether the postanoxic endothelial mitochondria is an important source of reactive oxygen species (ROS) using a chemical model of mitochondrial disruption to mimic the loss of mitochondrial integrity after anoxia/reoxygenation (A/R). The current objectives were to (1) determine the adhesion of human neutrophils to human umbilical vein endothelial cells exposed to antimycin A, a specific inhibitor of the mitochondrial cytochrome b-c(1) complex, and (2) define the mechanisms responsible for the early and late phases of neutrophil hyperadhesivity. Antimycin A caused a 5-fold increase in ROS generation and induced neutrophil adhesion at 30 min (phase 1) and 4 h (phase 2) that were quantitatively similar to that induced by A/R. Blockade of electron transport in antimycin A and A/R exposed cells with rotenone, amytal or thenoyltrifluoroacetate, but not myxothiazol, prevented neutrophil adhesion, confirming a role for mitochondrial ROS. Catalase inhibited phase 1 adhesion, indicating H(2)O(2) involvement. Anti-ICAM-1 or anti-P-selectin monoclonal antibodies (mAbs) attenuated phase 1 adhesion, while anti-E-selectin mAb attenuated phase 2 adhesion, consistent with roles for constitutive ICAM-1 and preformed P-selectin in early and E-selectin in late phase responses. Actinomycin D and cycloheximide or competing ds-oligonucleotides containing cognate DNA sequences of the nuclear factor kappaB or activator protein-1 attenuated phase 2 adhesion, implicating a role for de novo protein synthesis. Peak surface expression of the endothelial cell adhesion molecules correlated with peak adhesions at phases 1 and 2. These results show that disruption of mitochondrial respiratory chain elicits ROS production that mediates transcription-independent and -dependent surface expression of various adhesion molecules that leads to a two-phase neutrophil-HUVEC interaction similar to that induced by A/R.

Interleukin-8 expression in the esophageal mucosa of patients with gastroesophageal reflux disease

BACKGROUND

It has been reported that inflammatory cell infiltration can be detected in patients with endoscopically negative gastroesophageal reflux disease (GERD) as well as those with erosive reflux esophagitis. In this study, we examined the expression of mRNA for interleukin (IL)-8, a potent chemokine for neutrophils, in the esophageal mucosa of patients with GERD and compared the results with their endoscopic findings and symptoms.

METHODS

Biopsy samples were obtained from 80 patients. Endoscopic diagnosis was performed according to the Los Angeles classification. Patients with typical symptoms such as heartburn despite normal endoscopic findings were classified as the non-erosive GERD group. Total cellular RNA was extracted from the biopsy samples and IL-8 mRNA was quantified by real-time polymerase chain reaction (PCR). Localization of IL-8 protein in the esophageal mucosa was done by immunostaining.

RESULTS

Expression of IL-8 mRNA was correlated with the endoscopic grade of esophagitis or with inflammatory cell infiltration, but not with the symptoms of the patients. Expression of IL-8 mRNA was also detected in all patients with non-erosive GERD. The level of IL-8 expression in non-erosive GERD was low compared with that in erosive GERD, but was higher than that in normal controls. IL-8 immunostaining was found in the basal layers of the esophageal mucosa. Administration of lansoprazole, a proton-pump inhibitor, decreased both IL-8 mRNA and protein levels in the esophageal mucosa.

CONCLUSION

These results suggest that IL-8 in the esophageal mucosa may be involved in the pathogenesis of esophageal inflammation, including non-erosive GERD.

An orally active matrix metalloproteinase inhibitor, ONO-4817, reduces dextran sulfate sodium-induced colitis in mice

OBJECTIVE

Over-expression of matrix metalloproteinases (MMPs) can accelerate tissue destruction and disrupt subsequent tissue repair. A dextran sulfate sodium (DSS) colitis model was established to examine the effects of MMP inhibition, by an orally active MMP inhibitor ONO-4847, on colonic inflammation.

MATERIALS AND METHODS

Acute colitis was induced in female BALB/c mice by giving 8% DSS orally in drinking water for 7 days. The animals were randomized into groups receiving different concentrations of ONO-4847 or vehicle by oral gavage every day. mRNA levels of 4 MMPs and a tissue inhibitor of MMP (TIMP-1) were measured by RT-PCR in intestinal tissue isolated from mice after DSS administration. Colonic mucosal injury and inflammation were evaluated clinically, biochemically, and histologically. The clinical disease activity index (DAI), including body weight loss, stool consistency, and blood in feces, was examined. Moreover, mucosal tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma were determined by immunoassay.

RESULTS

The intestinal expression of MMP-3, -7, 9, and -12 and TIMP-1 mRNA was upregulated after DSS administration. Shortening of the colon was significantly reversed by ONO-4847 at a dose of 30 mg/kg. DAI in DSS-treated mice was significantly lower in the ONO-4847-treated mice compared with the control mice. Histological study also showed a reduced infiltration of inflammatory cells, especially neutrophils, and reducedmucosal cell disruption in ONO-4847-treated mice compared with the control mice. The increases in tissue-associated myeloperoxidase activity and thiobarbituric acid-reactive substances after DSS administration were both significantly inhibited by co-administration with ONO-4847. ONO-4847 also inhibited increases in the mucosal TNF-alpha and IFN-gamma content after DSS administration.

CONCLUSION

Improvements in DSS colitis in response to ONO-4847 suggest that activation of MMPs contributes to the initiation/amplification of colonic inflammatory injury by mechanisms including oxidative damage as well as enhancement of inflammatory cytokine release.

Neurocalcin-immunoreactive neurons in the petrosal ganglion innervate the taste bud

The distribution and origin of neurocalcin-immunoreactive (NC-ir) nerve fibers in the taste bud and carotid body were examined by an immunofluorescence method. In the circumvallate papilla of the tongue, NC-ir nerve fibers made subepithelial nerve plexuses and occasionally penetrated the taste bud. However, the carotid body was devoid of ir nerve fibers. In the petrosal ganglion, 32% of neurons were immunoreactive for NC. Such neurons were mostly medium-sized to large, and scattered throughout the ganglion. In the superior cervical and intralingual ganglia, numerous ir varicose fibers surrounded postsynaptic neurons. However, NC-ir could not be detected in cell bodies of these neurons. The retrograde tracing method indicated that NC-ir petrosal neurons innervated taste buds in the circumvallate papilla. NC-ir neurons may have a gustatory function in the petrosal ganglion.

Effect of mCOUP-TF1 deficiency on the glossopharyngeal and vagal sensory ganglia

Immunohistochemistry for calcitonin gene-related peptide (CGRP), tyrosine hydroxylase and calbindin D-28k was performed on the glossopharyngeal and vagal ganglia in mCOUP-TFI knockout mice to know the effect of its deficiency on different types of primary sensory neurons. In wild type and heterozygous mice, the glossopharyngeal and vagal ganglia contained abundant CGRP-, tyrosine hydroxylase- and calbindin D-28k-immunoreactive (IR) neurons. In the ganglia of mCOUP-TFI knockout mice, a 38% decrease of CGRP-IR neurons was detected. However, the number of tyrosine hydroxylase- or calbindin D-28k-neurons was not altered by the mCOUP-TFI deficiency. In the tongue of knockout mice, the number of CGRP-IR nerve fibers decreased compared to wild-type and heterozygous mice. The development of CGRP-IR petrosal neurons, which supply innervation of the tongue, may depend on mCOUP-TFI.

Ca2+/calmodulin-dependent protein kinase II in the rat cranial sensory ganglia

Immunohistochemistry for Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) was performed on the rat cranial sensory ganglia. More than one half of neurons was immunoreactive for the enzyme in the trigeminal (60%), jugular (70%), petrosal (55%) and nodose ganglia (63%). These neurons were mainly small to medium-sized. The co-expression study demonstrated that one half of CaMKII-immunoreactive (ir) neurons was also immunoreactive for calcitonin gene-related peptide (CGRP) or the vanilloid receptor subtype 1 (VR1) in the trigeminal, jugular and petrosal ganglia. In the nodose ganglion, CaMKII-ir neurons were mostly devoid of CGRP-immunoreactivity (ir) (8.2%) whereas the co-expression with VR1-ir was common among such neurons (72%). In the facial skin, nasal mucosa and palate, the epithelium and taste bud were innervated by CaMKII-ir nerve fibers. In addition, the retrograde tracing study demonstrated that 39.6% and 44.8% of trigeminal neurons which were retrogradely traced with fluorogold from the facial skin and nasal mucosa exhibited CaMKII-ir. Forty-six percent of petrosal neurons which innervated the soft palate were immunoreactive for the enzyme.

Effect of Brn-3a deficiency on parvalbumin-immunoreactive primary sensory neurons in the dorsal root ganglion

Immunohistochemistry for parvalbumin, a marker for primary proprioceptors, was performed on the dorsal root ganglion (DRG) of wildtype and knockout mice for Brn-3a at postnatal day 0 and embryonic day 18.5. The DRG contained many parvalbumin-immunoreactive (ir) neurons in wildtype (5.4%) and knockout mice (5.6%). Cell size analysis demonstrated that such neurons were mostly medium-sized to large in these mice. Therefore, it is unlikely that the survival of proprioceptors is dependent upon Brn-3a in the DRG. In the dorsal column and gray matter of the spinal cord of knockout mice, however, parvalbumin-ir nerve fibers were sparse compared to wildtype mice. The number of parvalbumin-ir varicosities around motoneurons decreased in the mutant. Thus, our data suggest that Brn-3a may play an important role in the central projection and terminal formation of DRG proprioceptors in the spinal cord.

VR1-, VRL-1- and P2X3 receptor-immunoreactive innervation of the rat temporomandibular joint

Immunohistochemistry for vanilloid receptor subtype 1 (VR1), vanilloid receptor 1-like receptor (VRL-1) and P2X3 receptor was performed in the rat temporomandibular joint (TMJ). Blood vessels in the articular disk and capsule, the synovial membrane and the fibrous tissue around the condylar process were innervated by VR1- or P2X3 receptor-immunoreactive (ir) nerve fibers. However, VRL-1-immunoreactivity (ir) could not be detected in the TMJ. Retrograde tracing and immunohistochemical methods revealed that 25%, 41% and 52% of TMJ neurons in the trigeminal ganglion (TG) exhibited VR1-, VRL-1- and P2X3 receptor-ir, respectively. VR1-ir TMJ neurons were mostly small to medium-sized, whereas VRL-1- and P2X3 receptor-ir TMJ neurons were predominantly medium-sized to large. In addition, 73%, 28% and 44% of VR1-, VRL-1- and P2X3 receptor-ir TMJ neurons, respectively, coexpressed calcitonin gene-related peptide (CGRP)-ir. The present study suggests that the TMJ has abundant nociceptors which respond to vanilloid compounds, protons, heat and extracellular ATP.

The somatostatin sst2A receptor in the rat trigeminal ganglion

Immunohistochemistry for the somatostatin sst2A receptor was performed on the rat trigeminal ganglion to know its function in the trigeminal nervous system. The immunoreactivity was detected in 9.4% of primary sensory neurons in the ganglion. These neurons were small to medium-sized (range=106.5-1123.2 microm(2); mean+/-S.D.=506.3+/-213.2 microm(2)) and predominantly located in the rostromedial part of the ophthalmo-maxillary division. They were also immunoreactive for calcitonin gene-related peptide and the vanilloid receptor subtype 1. In addition, 13.7% of trigeminal neurons which were retrogradely traced with fluorogold from the nasal mucosa exhibited sst2A receptor-immmunoreactivity. Trigeminal neurons which innervated the facial skin and tooth pulp were devoid of the immunoreactivity. In the brainstem trigeminal sensory nuclear complex, both the neuronal cell body and the neuropil exhibited sst2A receptor-immunoreactivity in the superficial medullary dorsal horn.The present study indicates that sst2A receptor-immunoreactive trigeminal nociceptors innervate the nasal mucosa. They may project to the superficial laminae of the medullary dorsal horn.

Lymph node hyalinization in elderly Japanese

Lymph node hyalinization has been comprehensively investigated using specimens obtained from elderly Japanese and white Americans. Onion-peel lesions and associated meshwork areas were often found in the medullary sinus of the thoracic node (mediastinal-type hyalinization), while eosinophilic, glassy and spotty lesions were consistently seen in B lymphocyte areas of the pelvic node (pelvic-type hyalinization). The mediastinal-type hyalinization was comprised of thin collagen fibrils (ca 50 nm in diameter), whereas the pelvic-type hyalinization had thick fibrils (ca 150 nm in diameter). This difference seemed to be consistent with a difference in composite collagen fibrils of vascular walls between the thoracic and pelvic regions. The pelvic-type hyalinization was often or sometimes seen in other nodes, such as cervical, axillary, abdominal and inguinal nodes, especially in white Americans. The mediastinal-type hyalinization, usually in combination with a sinus filled with anthracotic macrophages, tended to be observed in Japanese more frequently than in white Americans. Anthracosis seemed to be connected to the pathogenesis of the hyalinization. On the other hand, because the lesion was weakly positive for Factor VIII immunohistochemistry and because lesions were located along thin vessels, the pelvic-type hyalinization seemed to originate from vascular degeneration in the nodal cortex. Due to the high incidence and large proportion in total volume of the node, the hyalinization seems to be one of the major events that diminish the nodal filtration function and ruin the node with aging.

Pituitary adenylate cyclase-activating polypeptide-immunoreactive nerve fibers in rat and human tooth pulps

The distribution of pituitary adenylate cyclase-activating polypeptide (PACAP) was examined in the tooth pulp. In rat and human tooth pulps, PACAP-immunoreactive (IR) nerve fibers were observed around blood vessels and in the subodontoblastic and odontoblastic layers. The predentine and dentine were devoid of such nerve fibers. The double immunofluorescence method indicated the co-expression of PACAP with calcitonin gene-related peptide (CGRP) or vasoactive intestinal polypeptide (VIP). Virtually all PACAP-IR nerve fibers co-expressed CGRP-immunoreactivity (IR) in the rat tooth pulp suggesting their sensory function. In addition, a retrograde tracing method indicated that PACAP-IR nerve fibers in the rat tooth pulp originated from the trigeminal ganglion. On the other hand, almost all PACAP-IR nerve fibers in the human tooth pulp co-expressed VIP-IR and, thus, thought to be autonomic in nature.

The co-expression of VR1 and VRL-1 in the rat vagal sensory ganglia

Immunohistochemistry for two nociceptive transducers, the vanilloid receptor 1 (VR1) and vanilloid receptor 1-like receptor (VRL-1), was performed on the vagal sensory ganglia. In the jugular ganglion, VR1-immunoreactive (IR) neurons were small to medium-sized (range 49.7-1,125.6 microm(2), mean+/-S.D. 407.7+/-219.7 microm(2)), whereas VRL-1-IR neurons were medium-sized to large (range 223.6-1,341.1 microm(2), mean+/-S.D. 584.3+/-253.5 microm(2)). In the nodose ganglion, VR1- and VRL-1-IR neurons were mostly small to medium-sized (VR1: range 148.5-1464.4 microm(2), mean+/-S.D. 554.3+/-207.4 microm(2); VRL-1: range 161.7-1166.2 microm(2), mean+/-S.D. 541.9+/-186.2 microm(2)). The double immunofluorescence method revealed that co-expression of VR1-immunoreactivity among VRL-1-IR neurons was more abundant in the nodose ganglion (63%) than in the jugular ganglion (4%). The present study suggests that co-expression of VR1 and VRL-1 may be more common in visceral sensory neurons than in somatic sensory neurons.

The effect of rebamipide on Helicobacter pylori extract-mediated changes of gene expression in gastric epithelial cells

BACKGROUND

Recent studies have shown that Helicobacter pylori affects intracellular signal transduction in host cells, leading to the activation of transcriptional factors and the induction of pro-inflammatory cytokines. On the other hand, rebamipide, an anti-gastritis and anti-ulcer agent, could scavenge reactive oxygen species and reduce interleukin-8 (IL-8) expression in gastric epithelial cells induced by H. pylori-stimulation through the attenuated activation of nuclear factor-kappaB (NF-kappaB).

AIMS

In this study, we investigated the effects of rebamipide on gene expression in H. pylori-stimulated epithelial cells using DNA chip.

METHODS

H. pylori water extract (HPE) was prepared from NCTC11637, the type strain of H. pylori. Total RNA was extracted from MKN45 cells, a human gastric cancer cell line, following HPE-stimulation with and without rebamipide for 3 h, and differences in gene expression profiles were observed using GeneChip and Human 6800 probe array.

RESULTS

The GeneChip analysis demonstrated that 132 up-regulated genes and 873 down-regulated genes, such as growth factors, chemokines and transcription factors, were detected in MKN45 cells 3 h after stimulation of H. pylori. Among them, several genes, including bFGF, RANTES and MIP-2beta, were previously unknown to be expressed in H. pylori-stimulated human gastric cells. Rebamipide reduced expression of 119 genes encoding cytokines, growth factors and their receptors and transcription factors.

CONCLUSIONS

These findings suggest that rebamipide could inhibit inflammatory reactions and tumour progression by modifying H. pylori infection-induced gene expression in gastric epithelial cells.

Calcium-binding protein-immunoreactive innervation of the rat vibrissa

Immunohistochemistry detected calcium-binding proteins (CaBPs) in corpuscular and Merkel nerve endings of the rat vibrissa. CaBP-immunoreactive (ir) corpuscular endings were divided into two types: ramified and unramified endings. Ramified endings were subdivided into reticular and Ruffini endings. Unramified endings were identical to longitudinal lanceolate endings which have been described previously. Reticular and unramified endings as well as Merkel endings co-expressed neurocalcin (NC)- and parvalbumin (PV)-immunoreactivity (ir). However, such endings were devoid of peptide 19 (PEP19)-ir. PV-ir Ruffini endings were immunoreactive for PEP19 but not NC. The retrograde tracing method revealed that 34, 21 and 18% of trigeminal neurons which project to the infraorbital nerve exhibited NC-, PEP19- and PV-ir, respectively. In addition, 73 and 36% of the PV-ir neurons showed NC- and PEP19-ir, respectively. The content and co-expression of CaBPs in vibrissal low-threshold mechanoreceptors may depend on their terminal morphology.

[Fontan operation; progress in the methodology and its outcome]

In recent years, the outcome of the Fontan-type operation has markedly improved by the application of total cavopulmonary connection method, the staged strategy to reach Fontan operation and the application of fenestration. In this report, the histological aspect of the changes in the operative techniques and the long term outcome in our institution are described.

Effect of Brn-3a deficiency on parvalbumin-, calbindin D-28k-, calretinin- and calcitonin gene-related peptide-immunoreactive primary sensory neurons in the trigeminal ganglion

Immunohistochemistry for parvalbumin, calbindin D-28k, calretinin and calcitonin gene-related peptide (CGRP) was performed on the trigeminal ganglion and oro-facial tissues in Brn-3a wildtype and knockout mice at embryonic day 18.5 and postnatal day 0. In wildtype mice, the trigeminal ganglion contained abundant parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while the ganglion was almost devoid of calretinin-immunoreactive neurons. In Brn-3a knockout mice, a 63% decrease of parvalbumin-immunoreactive neurons was detected. In contrast, the absence of Brn-3a dramatically increased the number of calbindin D-28k-immunoreactive (3.5-fold increase) and calretinin-immunoreactive neurons (91-fold increase). The number of CGRP-immunoreactive neurons, however, was not altered by the Brn-3a deficiency. Cell size analysis indicated that loss of Brn-3a increased the proportions of small (<100 microm (2)) parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while it decreased those of large (>200 microm(2)) immunoreactive cells. Calretinin-immunoreactive neurons were either small or medium (100-200 microm (2)) in mutant mice. The oro-facial tissues contained parvalbumin-, calbindin D-28k- and CGRP-immunoreactive fibers, but not calretinin-immunoreactive ones in wildtype mice. In Brn-3a knockout mice, the number of parvalbumin-immunoreactive fibers markedly decreased in the infraorbital nerve and parvalbumin-immunoreactive endings disappeared in the vibrissa. In contrast, the number of calbindin D-28k-immunoreactive fibers increased significantly in the infraorbital and mental nerves. In addition, calbindin D-28k-immunoreactive endings appeared in the vibrissa. As well, some fibers showed calretinin-immunoreactivity in the infraorbital nerve of the mutant. However, no obvious change of CGRP-immunoreactive fibers was observed in the oro-facial region of knockout mice. Taken together, our data suggest that Brn-3a deficiency has effects on the expression of neurochemical substances in the trigeminal ganglion.

Effect of Brn-3a deficiency on nociceptors and low-threshold mechanoreceptors in the trigeminal ganglion

Immunohistochemistry for protein gene product 9.5 (PGP 9.5, a neuron specific protein) and vanilloid receptor 1-like receptor (VRL-1, a marker for medium-sized to large primary nociceptors) were used to assess the effects of Brn-3a deficiency on neuronal innervation of oral tissues and neurons of the trigeminal ganglion (TG). In the knockout mouse, the number of PGP 9.5-immunoreactive (-ir) nerve fibers decreased in the facial cutaneous and oral mucous epithelia, as well as the incisor and molar tooth germs. The reduction of PGP 9.5-ir Merkel endings was also observed in some vibrissae. No obvious change was detected in other tissues. Cell size analysis demonstrated that the proportion of small neurons markedly increased while that of medium-sized and large neurons significantly decreased in the TG of the mutant. Moreover, Brn-3a deficiency caused the disappearance of TG neurons which were immunoreactive for VRL-1. Together, our data suggest that nociceptors and low-threshold mechanoreceptors with medium-sized to large cell bodies may be sensitive to the loss of Brn-3a.

Helicobacter pylori infection potentiates aspirin induced gastric mucosal injury in Mongolian gerbils

BACKGROUND

Helicobacter pylori infection and non-steroidal anti-inflammatory drugs are two major causes of gastric ulceration but interactions between H pylori and these drugs in gastric mucosal injury are unclear.

AIMS

We studied the influence of experimental H pylori infection on gastric mucosal injury induced by aspirin.

SUBJECTS

Male Mongolian gerbils free of specific pathogens were used.

METHODS

H pylori ATCC43504 culture broth was administered by oral gavage at seven weeks of age. After three weeks, acidified aspirin (400 mg/kg) was administered orally, and three hours later the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemoattractive cytokine in rodents) were measured in gastric mucosa. To determine the role of neutrophils in these circumstances, antigerbil neutrophil rabbit serum (ANS) was administered to some animals 18 hours before aspirin.

RESULTS

Aspirin caused more extensive haemorrhagic erosions (33.1 (12.3) mm2) associated with greater MPO activity (1887.7 (598.5) microU/mg protein) and TBARS (0.33 (0.14) nmol/mg protein) and KC/GRO concentrations (28.3 (9.5) pg/mg protein) in infected than in uninfected gerbils (13.7 (2.3); 204.0 (68.9); 0.12 (0.06); 3.1 (0.8), respectively) Pretreatment with ANS inhibited the increases in gastric erosions, MPO activity, and TBARS but not KC/GRO concentration. The reduction in aspirin induced mucosal injury by administration of ANS was much greater in H pylori infected animals (65%) than in uninfected animals (31%).

CONCLUSIONS

H pylori infection potentiates aspirin induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.

Potential involvement of the AML1-MTG8 fusion protein in the granulocytic maturation characteristic of the t(8;21) acute myelogenous leukemia revealed by microarray analysis

The AML1 (RUNX1)-MTG8 (ETO) fusion transcription factor generated by the t(8;21) translocation is believed to deregulate the expression of genes that are crucial for normal differentiation and proliferation of hematopoietic progenitors, resulting in acute myelogenous leukemia. To elucidate the role of AML1-MTG8 in leukemogenesis, we used oligonucleotide microarrays to detect alterations in gene expression caused by ectopic expression of AML1-MTG8 in a murine myeloid progenitor cell line, L-G. Microarray analysis of approximately 6500 genes identified 32 candidate genes under the downstream control of AML1-MTG8. Among the 32 genes, 23 were not known to be regulated by AML1-MTG8. These included many granule protein genes and several cell surface antigen genes. Interestingly, AML1-MTG8 enhanced the expression of several genes that are usually induced during granulocytic differentiation, particularly those encoding azurophil granule proteins, including cathepsin G, myeloperoxidase and lysozyme. This indicates that AML1-MTG8 induces partial differentiation of myeloid progenitor cells into promyelocytes in the absence of the usual differentiation signals, while it inhibits terminal differentiation into mature granulocytes. Thus, AML1-MTG8 itself may play a crucial role in defining a unique cytologic type with abnormal maturation, characteristic of t(8;21) acute myelogenous leukemia.