[Preliminary clinical application of novel magnetic navigation and ultrasound-guided percutaneous transhepatic cholangiography drainage through the right liver duct for malignant obstructive jaundice]

Objective: To analyze the clinical application value of a novel magnetic navigation ultrasound (MNU) combined with digital subtraction angiography (DSA) dual-guided percutaneous transhepatic biliary drainage (PTCD) through the right hepatic duct for the treatment of malignant obstructive jaundice. Methods: Randomized controlled trial. The clinical data of 64 patients with malignant obstructive jaundice requiring PTCD through the right hepatic duct at the Hepatobiliary Center of the First Affiliated Hospital of Nanjing Medical University (Jiangsu Province People's Hospital) from December 2018 to December 2021 were retrospectively analyzed. The MNU group (n=32) underwent puncture guided by a novel domestic MNU combined with DSA, and the control group (n=32) underwent puncture guided by traditional DSA. The operation time, number of punctures, X-ray dose after biliary stenting as shown by DSA, patients' tolerance of the operation, success rate of the operation, pre- and post-operative total bilirubin, and incidence of postoperative complications were compared between the two groups. Results: The operation time of the MNU group was significantly shorter than that of the control group [(17.8±7.3) vs. (31.6±9.9) min, t=-6.35,P=0.001]; the number of punctures in the MNU group was significantly lower [(1.7±0.6) vs. (6.3±3.9) times, t=-6.59, P=0.001]; and the X-ray dose after biliary stenting as shown by DSA in the MNU group was lower than that in the control group [(132±88) vs. (746±187) mGy, t=-16.81,P<0.001]; Five patients in the control group were unable to tolerate the operation, and two stopped the operation, however all patients in the MNU group could tolerate the operation, and all completed the operation, with a success rate of 100% (32/32) in the MNU group compared to 93.8%(30/32) in the control group; the common complications of PTCD were biliary bleeding and infection, and the incidence of biliary bleeding (25.0%, 8/32) and infection (18.8%, 6/32) in the MNU group was significantly lower than that in the control group, 53.1% (17/32) and 28.1% (9/32), respectively. Conclusion: Magnetic navigation ultrasound combined with DSA dual-guided PTCD through the right biliary system for the treatment of malignant obstructive jaundice is safe and feasible.

Methionine restriction promotes cGAS activation and chromatin untethering through demethylation to enhance antitumor immunity

Cyclic GMP-AMP synthase (cGAS) is the major sensor for cytosolic DNA and activates type I interferon signaling and plays an essential role in antitumor immunity. However, it remains unclear whether the cGAS-mediated antitumor activity is affected by nutrient status. Here, our study reports that methionine deprivation enhances cGAS activity by blocking its methylation, which is catalyzed by methyltransferase SUV39H1. We further show that methylation enhances the chromatin sequestration of cGAS in a UHRF1-dependent manner. Blocking cGAS methylation enhances cGAS-mediated antitumor immunity and suppresses colorectal tumorigenesis. Clinically, cGAS methylation in human cancers correlates with poor prognosis. Thus, our results indicate that nutrient stress promotes cGAS activation via reversible methylation, and suggest a potential therapeutic strategy for targeting cGAS methylation in cancer treatment.

Air pollution characteristics, health risks, and source analysis in Shanxi Province, China

China is confronting an unprecedented air pollution problem. This study discussed the characteristics of air pollution and its risks on human health and conducted source analysis combined with local development in Shanxi Province in 2016 and 2017. Results demonstrated that the air pollution situation in Shanxi was deteriorating, with Taiyuan, Yangquan, Changzhi, Jincheng, Jinzhong, and Linfen being heavily polluted districts. Particulate matter (PM) was considered the major pollutant, but nitrogen dioxide and ozone showed a dominant trend recently. Furthermore, the health risks evaluated on the basis of a comprehensive air quality index (AAQI) and an aggregated risk index revealed a relatively high-risk level in Shanxi. Among the pollutants, the largest contributor was PM, followed by sulfur dioxide and ozone. Southern Shanxi had the largest pollution level and health risks, whereas Datong was the least polluted region. Source analysis suggested that the main driving forces of air pollution, besides natural factors, were urbanization, population size, civil vehicles, coal-based heavy industries, and high-energy consumption. Therefore, strengthening urban greening, vigorously adjusting and optimizing the industrial structure, and formulating a multi-domain cooperative control regime on air pollution, especially PM and ozone, should be promoted.

Examination of a coupling coordination relationship between urbanization and the eco-environment: a case study in Qingdao, China

A better understanding of the relationship between urbanization and the eco-environment is necessary to guide sustainable urban development and formulate environmental policies. In this study, the city of Qingdao was taken as an example. We evaluated the quantitative evolution of the relationship between urbanization and the eco-environment development from 2000 to 2018 by establishing the comprehensive index system and applying it to the coupling coordination model. Results showed the following: (1) The economic urbanization and eco-environment states offer the greatest contribution to the urbanization and eco-environment systems, respectively. (2) The coupling coordination relationship between urbanization and eco-environment conforms to an S-shaped curve, and the two systems have gradually moved from a "seriously uncoordinated and urbanization lag" stage at the beginning into a "good coordination and eco-environment lag" stage by the end of the research period. (3) Finally, the economic urbanization and response subsystems are essential determinants in the coupling relationship between urbanization and eco-environment. The research results can help the government better understand the complex coupling relationship and then formulate sustainable urbanization development strategies to better balance urbanization and eco-environmental protection.

Source analysis and risk assessment of heavy metals in development zones: a case study in Rizhao, China

The effects of heavy metal pollution in parks have caused widespread concern. This study investigated the concentrations and sources of eight heavy metals in the economic and technological development zone in Rizhao City. Geo-accumulation index ([Formula: see text]) and potential ecological risk index (PERI) were used to assess the pollution level of the development zone. Sources of heavy metals were analyzed through correlation analysis (CA) and principal component analysis (PCA). Descriptive statistics showed that many types of heavy metals accumulated in the development zone. The average concentrations of Pb, Cd, Hg, Ni, and Zn in the soil exceeded the background values of soil environment in Shandong Province. [Formula: see text] showed that only Hg in the soil was at the non-pollution to moderate pollution level. Meanwhile, sediments were polluted by Hg, Cd, and Zn, with their pollution level being higher than that of the soil. PERI showed that the soil presented moderate risk level and that the river sediment showed severe risk level. Hg and Cd exhibited the highest potential ecological risk. The results of the CA and PCA showed that the main sources of heavy metal pollution in the development zone are industrial activities, followed by atmospheric factors. Focus should thus be directed toward heavy metal pollution in development zones to protect human health and the soil environment.

Soil heavy metal contamination and health risk assessment associated with development zones in Shandong, China

Heavy metal pollution in soils of development zones has attracted wide attention. In this study, soil heavy metal pollution levels and health risks in 15 selected development zones in Shandong Province were investigated for the first time. Geo-accumulation and potential ecological risk indexes were used to assess pollution levels, and health risk was assessed using the US Environmental Protection Agency model. The soil was contaminated by various heavy metals, among which Hg was dominant. A total of 19% of the monitoring sites showed moderate ecological risk level, and low risk level was observed in general. Pollution control of Hg and Cd in each development zone must be strengthened. Health risk analysis showed that noncarcinogenic and carcinogenic risk levels for adults and children were acceptable or nearly acceptable. Positive matrix factorization model was used to identify three possible sources of heavy metal pollution, namely, industrial sources, atmospheric deposition, and transportation. Some specific measures should be taken to prioritize the control of Hg, As, and Cr for protecting the soil environment and human health, especially vulnerable groups, such as children.

Contrast-enhanced ultrasound for differential diagnosis of malignant and benign ovarian tumors: systematic review and meta-analysis

OBJECTIVE

To assess the performance of contrast-enhanced ultrasound (CE-US) in the differential diagnosis of malignant and benign ovarian tumors.

METHODS

We conducted a comprehensive literature search of PubMed and EMBASE to identify published articles evaluating the diagnostic potential of CE-US for the differentiation of benign and malignant ovarian tumors. Inclusion criteria were: (1) the study assessed the accuracy (or sensitivity and specificity) of CE-US for diagnosis of benign and malignant ovarian tumors; (2) it used surgery and histopathology as the reference standard for distinguishing between benign and malignant tumors; (3) it included data allowing construction of a 2×2 contingency table for true- and false-positives and negatives. We present summary sensitivity, specificity, diagnostic odds ratio (OR) and areas under the summary receiver-operating characteristics curves (AUCs).

RESULTS

Preliminary screening identified 103 papers, of which 11 fulfilled our predefined inclusion criteria and underwent final analysis. The pooled sensitivity and specificity of CE-US for diagnosis of benign and malignant ovarian tumors were 93% (95% CI, 89-96%) and 95% (95% CI, 92-96%), respectively. The pooled diagnostic OR was 171.2 (95% CI, 65.9-444.6) and the AUC was 0.98. I(2) values of sensitivity, specificity and diagnostic OR were 38.3%, 31.7% and 48.4%, respectively, all indicating moderate heterogeneity.

CONCLUSIONS

The evidence from available studies suggests CE-US is useful for discriminating between benign and malignant ovarian tumors; however, further studies are needed to examine whether CE-US has improved diagnostic test accuracy compared with that of standard two-dimensional Doppler sonography.

A novel biomarker Linc00974 interacting with KRT19 promotes proliferation and metastasis in hepatocellular carcinoma

Location-associated long noncoding RNA (lncRNA) was reported to interact with target protein via a cis-regulatory process especially for the Flank10kb class lncRNA. Based on this theory, we aimed to explore the regulatory mechanisms of Linc00974 and KRT19 (an lncRNA beyond the Flank10kb class with protein) when we first confirmed the aberrant expression in hepatocellular carcinoma in a previous study. Knockdown of Linc00974 resulted in an inhibition of cell proliferation and invasion with an activation of apoptosis and cell cycle arrest in vitro, which was also validated by a subcutaneous and tail vein/intraperitoneal injection xenotransplantation model in vivo. We further investigated the interaction pattern of Linc00974 and KRT19. MiR-642 was identified, by acting as the competing endogenous RNA in regulating Linc00974 and KRT19. Linc00974 was increased owing to an abnormal hypomethylation promoter, which induced the upregulation of KRT19 via ceRNA interaction, resulting in the activation of the Notch and TGF-β pathways as detected by cDNA microarray. We also discovered Linc00974F-1 stably expressed in the plasma. By the combined analysis of Linc00974F-1 with CYFRA21-1, we found that these joint indicators predicted growth and metastasis of tumor in HCC patients. In conclusion, the combination of Linc00974 and KRT19 may be novel indices for clinical diagnosis of tumor growth and metastasis in HCC, while Linc00974 may become a potential therapeutic target for the prevention of HCC progression.

Differences in biofilm formation and antimicrobial resistance of Pseudomonas aeruginosa isolated from airways of mechanically ventilated patients and cystic fibrosis patients

Pseudomonas aeruginosa biofilms exhibit increased antimicrobial resistance compared with planktonic isolates and are implicated in the pathogenesis of both acute and chronic lung infections. Whilst antibiotic choices for both infections are based on planktonic antibiotic susceptibility results, differences in biofilm-forming ability between the two diseases have not previously been explored. The aim of this study was to compare differences in biofilm formation and antibiotic resistance of P. aeruginosa isolated from intubated patients and from patients with chronic pulmonary disease associated with cystic fibrosis (CF). The temporal evolution of antibiotic resistance in clonal P. aeruginosa strains isolated from CF patients during periods of chronic infection and acute pulmonary exacerbation was also evaluated. Biofilm formation and biofilm antibiotic susceptibilities were determined using a modified microtitre plate assay and were compared with antibiotic susceptibility results obtained using traditional planktonic culture. Clonality was confirmed using random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) analysis. Pseudomonas aeruginosa isolates collected from intubated patients produced substantially more biofilms compared with CF isolates. There was considerable heterogeneity in biofilm-forming ability amongst the CF isolates and this was unrelated to pulmonary status. Biofilm antibiotic resistance developed rapidly amongst clonal CF isolates over time, whilst traditional antibiotic resistance determined using planktonic cultures remained stable. There was a significant positive correlation between imipenem/cilastatin and ceftazidime resistance and biofilm-forming ability. The variability in biofilm-forming ability in P. aeruginosa and the rapid evolution of biofilm resistance may require consideration when choosing antibiotic therapy for newly intubated patients and CF patients.

Axotomy alters neurotrophin and neurotrophin receptor mRNAs in the vagus nerve and nodose ganglion of the rat

Neurotrophins and neurotrophin receptors play an important role in survival and growth of injured peripheral nerves. To study the injury-mediated neurotrophic response in autonomic nerves, we investigated changes in mRNA expression of neurotrophins and their receptors in the transected vagus nerve and nodose ganglion. Studies using in situ hybridization histochemistry showed that axotomy of the cervical vagus nerve resulted in increased expression of mRNAs for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3), and for TrkA, TrkB, and TrkC receptors in non-neuronal cells at both the proximal and distal segments of the transected cervical vagus nerve. Moreover, NGF protein was increased in the distal end, and NT-3 protein was increased in both the proximal and the distal ends of the transected nerve 3 days after axotomy. No change of p75(NTR) mRNA was detected in the transected vagus nerve. The induction of each neurotrophin and Trk receptor mRNA was apparent within 1 day after the axotomy and was sustained at least 14 days. By 45 days after the axotomy, a time when axonal reconnection with target tissue is made (integrity of the nerve-target connection was confirmed by the retrograde transport of FluoroGold from the stomach to vagal cell bodies), the levels of neurotrophin and Trk mRNAs in the vagus nerve declined to pre-axotomy levels. TrkA, TrkC, and p75(NTR) mRNA-containing vagal sensory neurons in the nodose ganglion were reduced in number after cervical vagotomy. Neurotrophin-mRNA-containing neurons were not found in the nodose ganglia from either intact or vagotomized rats. The axotomy-induced up-regulation of neurotrophins and Trk receptors mainly in the non-neuronal cells at or near the site of transection suggests that neurotrophins are involved in the survival and regeneration process of the vagus nerve after injury.

Axonal transport of neurotrophins by visceral afferent and efferent neurons of the vagus nerve of the rat

The receptor-mediated axonal transport of [125I]-labeled neurotrophins by afferent and efferent neurons of the vagus nerve was determined to predict the responsiveness of these neurons to neurotrophins in vivo. [125I]-labeled neurotrophins were administered to the proximal stump of the transected cervical vagus nerve of adult rats. Vagal afferent neurons retrogradely transported [125I]neurotrophin-3 (NT-3), [125I]nerve growth factor (NGF), and [125I]neurotrophin-4 (NT-4) to perikarya in the ipsilateral nodose ganglion, and transganglionically transported [125I]NT-3, [125I]NGF, and [125I]NT-4 to the central terminal field, the nucleus tractus solitarius (NTS). Vagal afferent neurons showed minimal accumulation of [125I]brain-derived neurotrophic factor (BDNF). In contrast, efferent (parasympathetic and motor) neurons located in the dorsal motor nucleus of the vagus and nucleus ambiguus retrogradely transported [125I]BDNF, [125I]NT-3, and [125I]NT-4, but not [125I]NGF. The receptor specificity of neurotrophin transport was examined by applying [125I]-labeled neurotrophins with an excess of unlabeled neurotrophins. The retrograde transport of [125I]NT-3 to the nodose ganglion was reduced by NT-3 and by NGF, and the transport of [125I]NGF was reduced only by NGF, whereas the transport of [125I]NT-4 was significantly reduced by each of the neurotrophins. The competition profiles for the transport of NT-3 and NGF are consistent with the presence of TrkA and TrkC and the absence of TrkB in the nodose ganglion, whereas the profile for NT-4 suggests a p75 receptor-mediated transport mechanism. The transport profiles of neurotrophins by efferent vagal neurons in the dorsal motor nucleus of the vagus and nucleus ambiguus are consistent with the presence of TrkB and TrkC, but not TrkA, in these nuclei. These observations describe the unique receptor-mediated axonal transport of neurotrophins in adult vagal afferent and efferent neurons and thus serve as a template to discern the role of specific neurotrophins in the functions of these visceral sensory and motor neurons in vivo.

Effects of removing circulatory tumor necrosis factor by immunoadsorption on experimental endotoxin shock animals

OBJECTIVE

To evaluate the effects of removing circulatory tumor necrosis factor (TNF) by immunoadsorption on endotoxin shock animals.

METHODS

Sixty New Zealand white rabbits were injected intravenously with lethal dose of endotoxin (10 Billion cfu/kg E. Coli endotoxin) and randomly divided into 3 groups: perfusion group, hemoperfusion started at 1 hour after injecting endotoxin through immunoadsorbent columns against TNF; pseudoperfusion group, hemoperfusion through blank columns; and control group, injected with endotoxin only. The arterial pressure, microcirculation of the mesentery, plasma levels of TNF, IL-1, IL-6, IL-8, nitrite, endothelin-1 (ET-1), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine were measured and analyzed and finally the survival rate was observed.

RESULTS

Plasma levels of TNF were sharply reduced after immunoadsorption. Moreover, release of IL-1, IL-6, IL-8, NO and ET-1 were also attenuated. Hemodynamic abnormalities could be improved and survival rate ameliorated significantly.

CONCLUSION

Specific immunoadsorption of circulating TNF might be a new and effective therapy for endotoxin shock.

Neurochemistry of the nodose ganglion

Placode-derived general visceral afferent neurons of the nodose ganglion transmit visceral sensory information from specialized sensory endings of the vagus nerve and its branches to the nucleus of the solitary tract. These neurons are critical in relaying information such as elevations in blood pressure, changes in blood oxygenation, passage of contents through the esophagus and intestines, and distention of the heart, stomach, and lungs to the CNS for reflex maintenance of visceral functions. Multiple neurotransmitters, neuropeptides, calcium binding proteins, and other neuroactive substances are associated with neurons of the nodose ganglion. Many neurons colocalize 2 or more neuroactive substances creating the potential for complex interactions of neurochemical signals in the NTS. Neurons of the nodose ganglion also contain a variety of receptors which respond to transmitters, inflammatory mediators, and neurotrophic factors. The contents of these neurochemicals and receptors are not static as alterations in their expression are noted in response to epigenetic influences. Although not yet well understood, potential factors and mechanisms regulating neurochemical events in the nodose ganglion neurons are discussed.

Immunocytochemical studies of the 5-HT(1A) receptor in ventral medullaryneurons that project to the intermediolateral cell column and contain serotonin or tyrosine hydroxylase immunoreactivity

Activation of serotonin-1A receptors (5-HT(1A)R) in the medulla oblongata lowers sympathetic nerve discharge and blood pressure. Binding sites for 5-HT(1A)R ligands are present in ventral medullary nuclei [e.g., rostral ventrolateral medulla (RVLM), raphe pallidus (RPa), and parapyramidal region (PPR)] that project to sympathetic preganglionic neurons in the intermediolateral cell column (IML). However, the projections and the neurochemical contents of the ventral medullary neurons that are likely to be involved in the hypotensive actions of 5-HT(1A) agonists are unclear. Using a sheep antibody to a fragment of the third intracellular loop of the 5-HT(1A)R, we localized 5-HT(1A)R immunoreactivity (ir) to IML-projecting neurons that were retrogradely labeled with rhodamine beads injected into the IML of adult male rats. The percentages of IML-projecting neurons containing 5-HT(1A)R-ir were 49% in RPa, 34% in PPR, and 44% in RVLM. Using multiple-immunofluorescence labeling, we also demonstrated 5-HT(1A)R-ir in serotonergic (5-HT) and in catecholaminergic (tyrosine hydroxylase; TH-ir) neurons of the ventral medulla. The percentages of 5-HT-ir neurons containing 5-HT(1A)R-ir were 28% in RPa, 18% in PPR, and 31% in raphe obscurus. In addition, 5-HT(1A)R-ir was present in 14% of TH-ir neurons of the RVLM. Moreover, some IML-projecting neurons in the PPR and RPa were doubly immunolabeled for 5-HT(1A)R-ir and 5-HT, and some IML-projecting neurons in the RVLM were doubly immunolabeled for 5-HT(1A)R-ir and TH-ir. These data provide anatomical evidence for the presence of 5-HT(1A)R on serotonergic and catecholaminergic bulbospinal neurons and for their potential role in directly modifying the activity of these ventral medullary neurons.

Presence and localization of neurotrophin receptor tyrosine kinase (TrkA, TrkB, TrkC) mRNAs in visceral afferent neurons of the nodose and petrosal ganglia

The presence of mRNAs to the high affinity tyrosine kinase (Trk) receptors for neurotrophins was studied in visceral afferent neurons of the nodose and petrosal ganglia of adult and neonatal rats using in situ hybridization histochemistry. Neurons containing TrkA mRNA were found in the adult nodose and petrosal ganglia. About 10% of nodose ganglion neurons and 38% of petrosal ganglion neurons contained TrkA mRNA. The nodose and petrosal ganglia from 1 day old neonates also expressed TrkA mRNA. No TrkB mRNA-containing neurons were detected in the adult nodose and petrosal ganglia, whereas TrkB mRNA was detected in 1 day old neonatal nodose and petrosal ganglia. TrkC mRNA was found in about 9% of nodose ganglion neurons and 11% of petrosal ganglion neurons of adult rats. Likewise, low but detectable levels of TrkC mRNA were seen in 1 day old neonatal nodose and petrosal ganglia. These data demonstrate the presence of TrkA and TrkC in the adult nodose and petrosal ganglia and provide a substrate for the ongoing neurotrophin-induced regulation of these placodally derived visceral afferent neurons. The altered expression of Trk receptor mRNAs in the nodose and petrosal ganglia between the adult and neonatal rats may reflect developmentally regulated changes in neurotrophin responsiveness.

[Evaluation of operative corrigent degree of scoliosis by improved Cobb's angle degree of preoperative suspensive roentgenogram]

To achieve best operative result in correction of scoliosis, and avoid complications of the nerve system due to excess correction, we compared the statistical results of modified Cobb's degree of preoperative suspensive roentgenogram and operative corrigent degrees of 331 patients with scoliosis, including 219 with idiopathic scoliosis. The modified Cobb's degrees of the whole group was 20.15 +/- 9.41 in suspension, the operative corrigent degree was 35.34 +/- 13.05, and the operation-suspension difference was 14.62 +/- 11.02. Referring to idiopathic scoliosis, it was 21.79 +/- 8.39, 37.44 +/- 11.82, 15.58 +/- 9.91 respectively. And the statistacal study was performed according to scoliosis type, involved segments, curvature degree, and ages. The parameters were very helpful in the evaluation of currigent effect before operation.

Inhibition of axoplasmic transport in the rat vagus nerve alters the numbers of neuropeptide and tyrosine hydroxylase messenger RNA-containing and immunoreactive visceral afferent neurons of the nodose ganglion

Previous work showed that axotomy-induced deafferentation of the placode-derived visceral afferent neurons of the nodose ganglion altered their expression of some neuropeptides and tyrosine hydroxylase. The present studies were designed to selectively evaluate the loss of axonal transport on the numbers of vasoactive intestinal polypeptide, tyrosine hydroxylase, and calcitonin gene-related peptide mRNA-containing and immunoreactive neurons in the nodose ganglion of the adult rat. Vinblastine (0.15 mM) application to the cervical vagus nerve was used to block axonal transport between ganglionic perikarya and peripheral targets. In situ hybridization histochemistry with 35S-labeled oligonucleotide probes was used to both quantify the number of mRNA-containing neurons and to assess the density of mRNA expression per neuron, and immunocytochemistry was used to visualize the number of immunoreactive neurons. The efficacy of vinblastine to inhibit axonal transport was verified by evaluating the build-up of calcitonin gene-related peptide immunoreactive in the vagus nerve immediately rostral to the site of drug application. The absence of vinblastine-induced neuronal damage was verified by the relative absence of degenerating nerves in the vagus nerve caudal to the site of drug application. Vinblastine treatment of the vagus nerve increased the numbers of vasoactive intestinal peptide mRNA-containing neurons and vasoactive intestinal peptide-immunoreactive neurons in the nodose ganglion at three, seven and 14 days, and increased the numbers of calcitonin gene-related peptide mRNA-containing and calcitonin gene-related peptide-immunoreactive neurons in the nodose ganglion at one, three and seven days. The average labeling density of vasoactive intestinal peptide mRNA-containing neurons was also increased following vinblastine treatment. Vinblastine treatment of the cervical vagus nerve, however, led to the appearance of low-labeling density calcitonin gene-related peptide mRNA-neurons and resulted in reduction of the average labeling density for calcitonin gene-related peptide mRNA-containing neurons. In contrast, application of vinblastine to the cervical vagus nerve, decreased the number of tyrosine hydroxylase mRNA-containing and tyrosine hydroxylase-immunoreactive neurons in the nodose ganglion. In summary, inhibition of the axoplasmic transport between the periphery and the visceral sensory perikarya appeared to alter vasoactive intestinal peptide, calcitonin gene-related peptide, and tyrosine hydroxylase expression and content in visceral sensory neurons of the nodose ganglion. These data suggest the presence of an axonally transported influence on the regulation of neuropeptide and neurotransmitter enzyme synthesis in mature placode-derived visceral sensory neurons.

Plasticity of tyrosine hydroxylase and vasoactive intestinal peptide messenger RNAs in visceral afferent neurons of the nodose ganglion upon axotomy-induced deafferentation

The nodose ganglion contains placode-derived visceral sensory neurons of the vagus nerve. Previous study showed that axotomy-induced deafferentation reduced the number of tyrosine hydroxylase-immunoreactive and increased the number of vasoactive intestinal peptide-immunoreactive neurons in the ganglion. The present study was conducted to determine whether the changes in neuropeptide/neurotransmitter enzyme content are associated with changes in the expression of tyrosine hydroxylase and vasoactive intestinal peptide messenger RNAs in the nodose ganglion. We used in situ hybridization histochemistry with 35S-labeled oligonucleotide probes for tyrosine hydroxylase and vasoactive intestinal peptide precursor messenger RNAs. Peripheral axotomy of visceral afferent inputs reduced tyrosine hydroxylase messenger RNA and increased vasoactive intestinal peptide messenger RNA expression in neurons of the nodose ganglion of the rat. The number of tyrosine hydroxylase messenger RNA-containing neurons was significantly reduced at three, seven and 14 days after axotomy-induced deafferentation compared with intact and sham-operated controls. Labeling density of tyrosine hydroxylase messenger RNA-containing neurons was significantly reduced at three and seven days. Conversely, the number of vasoactive intestinal peptide messenger RNA-containing neurons increased significantly at three, seven and 14 days, while the labeling density of vasoactive intestinal peptide messenger RNA-containing neurons also increased at one, three, seven and 14 days. The results of the present study indicate that the axotomy-induced down-regulation of tyrosine hydroxylase and up-regulation of vasoactive intestinal peptide in the neurons of the nodose ganglion are associated with changes in their messenger RNAs in response to axotomy-induced deafferentation.

Anatomical evidence for the presence of glutamate or enkephalin in noradrenergic projection neurons of the locus coeruleus

This paper reviews the anatomical evidence for the presence of glutamate (GLU) in noradrenergic neurons of the nucleus locus coeruleus (LC) and adjacent nuclei in the dorsolateral pontine tegmentum (DLPT) that project to the spinal cord, cerebellum, or cerebral cortex. Additionally, the evidence for the existence of methionine-enkephalin (ENK) in noradrenergic neurons of the DLPT that project to the spinal cord of the cat is reviewed. In these studies, we have combined the retrograde transport of either Fast Blue (FB), rhodamine labeled latex microspheres (MS), or rhodamine labeled dextran and indirect immunofluorescence histochemistry to determine whether the neurons that contain tyrosine hydroxylase (TH) and project to these terminal fields also contain GLU or ENK. The neurons of the cat that project to the spinal cord, cerebellum, and neocortex were observed in the nucleus LC and Kölliker-Fuse (KF) nucleus. They were also present, to a lesser extent, in the nucleus subcoeruleus (SC) and nuclei parabrachialis medialis (PBM) and lateralis (PBL). In the rat the majority of the neurons that project to the neocortex and hippocampus were located in the nucleus LC. Our data revealed a major proportion of these neurons to be immunostained for both GLU and TH (cat, rat), or ENK and TH (cat). Functional implications of such colocalized neurochemicals within individual LC projection neurons are discussed.

Bulbospinal neurons of the cat that co-contain serotonin and methionine enkephalin

The present study utilizes a combined retrograde transport of Fast Blue (or rhodamine-labeled latex microspheres) and simultaneous immunofluorescence technique to demonstrate directly the coexistence of serotonin and methionine enkephalin in bulbospinal neurons of the cat. The bulbospinal neurons that immunostained for both serotonin and enkephalin were observed, without any distinct somatotopic organization, in the nuclei raphe pallidus, obscurus and magnus. They were also observed in the nucleus reticularis magnocellularis and the ventrolateral medulla (cell group B1/3). Among the bulbospinal neurons encountered within individual 5-HT-rich medullary nuclei, high proportions of these neurons co-containing serotonin and methionine enkephalin were evidenced in the nucleus raphe obscurus (64%) and nucleus raphe pallidus (56%), less so in cell group B1/3 (41%), nucleus raphe magnus (39%), and the nucleus reticularis magnocellularis (29%). Physiological significance of such a morphological substrate is discussed.

Peripheral deafferentation alters calcitonin gene-related peptide mRNA expression in visceral sensory neurons of the nodose and petrosal ganglia

Visceral sensory neurons of the glossopharyngeal and vagus nerves are located in the petrosal and nodose ganglia, respectively. Our previous studies showed that peripheral axotomy which removes afferent input to visceral sensory perikarya decreased the number of calcitonin gene-related peptide (CGRP)-immunoreactive (ir) neurons in the petrosal but not the nodose ganglion. To evaluate axotomy-induced changes in CGRP mRNA expression, we used in situ hybridization histochemistry with 35S-labeled oligonucleotide probes. CGRP mRNA-containing neurons were studied 1, 3, 7 and 14 days after peripheral deafferentation of the left nodose and petrosal ganglia via transection of the left cervical vagus, superior laryngeal, glossopharyngeal and carotid sinus nerves. The numbers of CGRP mRNA-containing neurons in the deafferented petrosal ganglion were significantly reduced at 3, 7 and 14 days compared to either intact or sham-operated control ganglia. However, the density of hybridization product in the positively-labeled petrosal ganglion cells was not significantly changed. The numbers of CGRP mRNA-containing neurons in the deafferented nodose ganglion were significantly reduced at 3 and 7 days. These data suggest that axotomy-induced changes in CGRP-ir neurons of the petrosal ganglion correlate with changes in CGRP mRNA and probably result from altered CGRP gene expression. In addition, in situ hybridization histochemistry revealed changes in CGRP neurons of the nodose ganglion which were not apparent with immunocytochemistry.

Neurokinin A coexists with substance P and serotonin in ventral medullary spinally projecting neurons of the rat

The coexistence of neurokinin A (NKA) with substance P (SP) and serotonin (5-HT) in ventral medullary neurons of the parapyramidal region and nucleus raphe pallidus of the rat was studied using multiple immunofluorescence labeling. Nearly all of the NKA-immunoreactive (IR) cells in the parapyramidal region and raphe pallidus were SP-IR nd 5-HT-IR, whereas about 70% of the SP-IR neurons and about 60% of the 5-HT-IR neurons contained NKA-IR. There were no apparent differences in the patterns of coexistence between parapyramidal and raphe pallidus neurons. NKA-IR neurons, which colocalized SP-IR and 5-HT-IR, were studied for projections to the lumbar and thoracic spinal cord by use of retrograde transport of fluorescent tracer. Whereas about 50% of the retrogradely labeled neurons of the parapyramidal region and raphe pallidus contained NKA-IR, nearly all of the NKA-IR neurons projected to the thoracic and lumbar spinal cord. In addition, some NKA-IR neurons in the ventral medulla were retrogradely labeled with tracer from localized injections into the thoracic intermediolateral cell column. In summary, this study demonstrated that NKA-IR is colocalized with SP-IR in bulbospinal serotonergic neurons of the parapyramidal region and raphe pallidus, which are known to regulate sensory, motor, and autonomic activities of the spinal cord.

Cotransmitter-mediated locus coeruleus action on motoneurons

This article reviews evidence for a direct noradrenergic projection from the dorsolateral pontine tegmentum (DLPT) to spinal motoneurons. The existence of this direct pathway was first inferred by the observation that antidromically evoked responses occur in single cells in the locus coeruleus (LC), a region within the DLPT, following electrical stimulation of the ventral horn of the lumbar spinal cord of the cat. We subsequently confirmed that there is a direct noradrenergic pathway from the LC and adjacent regions of the DLPT to the lumbar ventral horn using anatomical studies that combined retrograde tracing with immunohistochemical identification of neurotransmitters. These anatomical studies further revealed that many of the noradrenergic neurons in the LC and adjacent regions of the DLPT of the cat that send projections to the spinal cord ventral horn also contain colocalized glutamate (Glu) or enkephalin (ENK). Recent studies from our laboratory suggest that Glu and ENK may function as cotransmitters with norepinephrine (NE) in the descending pathway from the DLPT. Electrical stimulation of the LC evokes a depolarizing response in spinal motoneurons that is only partially blocked by alpha 1 adrenergic antagonists. In addition, NE mimicks only the slowly developing and not the fast component of LC-evoked depolarization. Furthermore, the depolarization evoked by LC stimulation is accompanied by a decrease in membrane resistance, whereas that evoked by NE is accompanied by an increased resistance. That Glu may be a second neurotransmitter involved in LC excitation of motoneurons is supported by our observation that the excitatory response evoked in spinal cord ventral roots by electrical stimulation of the LC is attenuated by a non-N-methyl-D-aspartate glutamatergic antagonist. ENK may participate as a cotransmitter with NE to mediate LC effects on lumbar monosynaptic reflex (MSR) amplitude. Electrical stimulation of the LC has a biphasic effect on MSR amplitude, facilitation followed by inhibition. Adrenergic antagonists block only the facilitator effect of LC stimulation on MSR amplitude, whereas the ENK antagonist naloxone reverses the inhibition. The chemical heterogeneity of the cat DLPT system and the differential responses of motoneurons to the individual cotransmitters help to explain the diversity of postsynaptic potentials that occur following LC stimuli.

Opioid action on spinal cord reflexes due to dorsolateral pontine tegmentum stimulation

Electrical stimulation of the dorsolateral pontine tegmentum (DLPT) produces phasic facilitatory and inhibitory actions on the lumbar spinal monosynaptic reflexes (MSRs) of both flexor and extensor muscle nerves in the decerebrate cat. Naloxone, an opioid receptor antagonist, given intravenously or intraspinally enhanced the DLPT-induced potentiation of MSRs in most of the reflexes studied. However, systemic naloxone had no significant effect on the unconditioned MSR of the spinal cord. Intraspinal microinjections of naloxone significantly attenuated the DLPT-induced inhibition of MSRs of both flexors and extensors, similar to the action of systemic injection of naloxone, indicating a direct opioid action at the spinal ventral horn level upon DLPT stimulation. Results of the present experiment further support the anatomical finding that there are pontospinal enkephalinergic pathways in the cat, and indicate that these descending pathways modulate spinal motor outflow.

Neurokinin B peptide-2 neurons project from the hypothalamus to the thoracolumbar spinal cord of the rat

The presence and location of CNS neurokinin B peptide-2-like immunoreactive neurons that project to the spinal cord were studied by a combination of retrograde transport of fluorescent dye (FluoroGold) and fluorescence immunocytochemistry. After injections of FluoroGold into the thoracic or lumbar segments of the rat spinal cord, serial sections of brain were stained with antisera directed against neurokinin B peptide-2. The results of the study showed that neurokinin B peptide-2-like immunoreactive neurons were located in the nucleus arcuate, median eminence, ventral and external bed nuclei of the stria terminalis, dorsal hypothalamic area, and medial habenula. Neurokinin B peptide-2 neurons that give rise to the long descending projections from the hypothalamus to thoracolumbar spinal cord were found only in the dorsal hypothalamic area. Approximately 36% of the neurokinin B peptide-2 neurons in the dorsal hypothalamic area projected to the spinal cord, whereas about 28% of the spinal projecting neurons in the dorsal hypothalamic area contained neurokinin B peptide-2-like immunoreactivity. Most of the spinal projecting neurokinin B peptide-2 neurons in the dorsal hypothalamic area had a cell size of 15 x 25 microns. In the spinal cord, immunoreactive neurokinin B peptide-2 fibers and terminals were distributed mainly in the superficial dorsal horn and the central autonomic area, with the highest density in laminae II and X, with less density in laminae IV and V. A few neurokinin peptide-2 fibers and terminals were also found in the ventral horn of the spinal cord. The results of the present study show that hypothalamic neurokinin B peptide-2 neurons are the main source of the spinal neurokinin B peptide-2.

Immunohistochemical evidence for coexistence of methionine-enkephalin and tyrosine hydroxylase in neurons of the locus coeruleus complex projecting to the spinal cord of the cat

Previous studies have revealed the presence of pontospinal neurons with either methionine-enkephalin- or tyrosine hydroxylase-like immunoreactivity in the dorsolateral pontine tegmentum of the cat. Using a combined fast blue retrograde transport technique and simultaneous immunofluorescence histochemistry, the present study was designed to reveal the coexistence of enkephalin and tyrosine hydroxylase in cat coerulospinal neurons and to determine if and to what extent the coerulospinal pathway is heterogeneous. Fast blue-labelled neurons with tyrosine hydroxylase- and enkephalin-like immunoreactivities were found in the nucleus locus coeruleus, nucleus subcoeruleus, Kölliker-Fuse nucleus, and the medial and lateral parabrachial nuclei. Approximately 87% of tyrosine hydroxylase-like immunoreactive neurons had enkephalin-like immunoreactivity, whereas about 76% of the enkephalin-like immunoreactive neurons had tyrosine hydroxylase-like immunoreactivity. About 71% of all coerulospinal neurons exhibited both tyrosine hydroxylase- and enkephalin-like immunoreactivities. These findings indicate that coerulospinal activity may lead to spinal cord effects reflecting both norepinephrine and enkephalin activity in most cases but do not rule out each transmitter's isolated functions.

Coerulospinal cells containing neuropeptide Y in the cat

Spinally projecting neuropeptide Y (NPY)-immunoreactive cells were sought in the feline locus coeruleus (LC) nuclear complex after horseradish peroxidase (HRP) injection into the lumbar cord; HRP injection was followed by intracerebroventricular colchicine administration. Our results revealed that a significant number (approximately 20% of all descending cells from the LC complex) of spinally projecting NPY-immunoreactive neurons arise from the LC alpha, the subcoeruleus and the Kölliker-Fuse nuclei. Other nonspinally projecting NPY-containing cells were also evident in the laterodorsal tegmental nucleus and the LCd, in addition to those occurring in the aforementioned LC nuclear complex.

Pontospinal transmitters and their distribution

The dorsolateral pontine tegmentum of the cat is known to contain a large population of catecholaminergic neurons. Additionally, several studies have also shown the presence of other neurochemicals (acetylcholine, enkephalin, neuropeptide Y, serotonin, somatostatin and substance P). In this study, we have employed retrograde transport of horseradish peroxidase in combination with immunocytochemistry to determine the locations of pontospinal neurons which contain catecholamine, enkephalin, neuropeptide Y, and serotonin. Furthermore, we have combined the retrograde transport of Fast Blue and immunofluorescence histochemistry to determine whether enkephalin-containing neurons are catecholaminergic. All pontospinal neurons, irrespective of the neurochemical content, were observed in the ventral and lateral parts of the dorsolateral pontine tegmentum at coronal levels P1.8-P4.0. These neurons were located in the nuclei locus coeruleus alpha and subcoeruleus and the Kölliker-Fuse nucleus. A high concentration of these neurons was evident in the Kölliker-Fuse nucleus when compared to the nuclei locus coeruleus alpha and subcoeruleus. Quantitative data have revealed that enkephalin is contained in a large proportion of the pontospinal catecholaminergic neurons (75%). The observations suggest that catecholaminergic neurons may contain one or more putative peptide neurotransmitters.

Localization of enkephalinergic neurons in the dorsolateral pontine tegmentum projecting to the spinal cord of the cat

The dorsolateral pontine tegmentum of the cat is known to contain enkephalinergic neurons, with most of the enkephalin co-contained in the catecholaminergic neurons; however, enkephalinergic cells projecting to the spinal cord have not been identified. This study employs retrograde transport of horseradish peroxidase in combination with methionine-enkephalin or tyrosine hydroxylase immunocytochemistry to 1) determine the locations of pontospinal enkephalinergic neurons and 2) compare these with the locations of pontospinal catecholaminergic neurons. Pontospinal enkephalinergic neurons were observed in the nuclei locus coeruleus and subcoeruleus and the Kölliker-Fuse nucleus. A high concentration of these neurons was evident in the Kölliker-Fuse nucleus when compared to the nuclei locus coeruleus and subcoeruleus (P less than .01). Both the enkephalinergic and catecholaminergic neurons projecting to the spinal cord were located in the same general areas of the dorsolateral pontine tegmentum and there was no significant difference in the mean diameters of these two neuronal types (P greater than .05). Quantitative data concerning the pontospinal enkephalinergic neurons correlated well with previous data on pontospinal catecholaminergic neurons (Reddy et al., Brain Res. 491:144-149, '89). A majority of the descending neurons from the dorsolateral pontine tegmentum contain enkephalin (72-80%) and catecholamine (80-87%). The observations suggest that enkephalin is contained in many of the pontospinal catecholaminergic neurons.

Spinally projecting noradrenergic neurons of the dorsolateral pontine tegmentum: a combined immunocytochemical and retrograde labeling study

Two to three days following injection of horseradish peroxidase (HRP) into the spinal cords of 5 cats, the animals were sacrificed and perfused, and the brainstems removed and sectioned. The sections were then processed for HRP and, immunocytochemically, for tyrosine hydroxylase (TH). The dorsolateral pontine tegmentum was divided into the locus coeruleus, subcoeruleus and Kölliker-Fuse nucleus; the mean percentage of pontospinal neurons containing TH were found to be 85.5 +/- 2.5 (S.E.M.), 79.6 +/- 5.6 and 87.1 +/- 3.1, respectively. The cell diameters of locus coeruleus cells were also measured.