The evolving landscape of publishing in the field of pain: An automated bibliometric analysis from 1975 to 2020

BACKGROUND

The aims of this bibliometric analysis were (1) a longitudinal analysis of the publication landscape in the field of pain (1975-2020) and (2) to characterize the overall publication profiles for two selected journals: European Journal of Pain and PAIN® utilizing an automated approach.

METHODS

Database searches in Scopus extracted all journals with 'pain' in their title. For the two specific journals, papers were manually/automatically profiled into preclinical, human and translational studies.

RESULTS

A gross list of 64 journals in the field of pain consisting of both active and ceased journals in Scopus were included in this analysis which identified 62,565 papers with approximately 4000 papers published/year. These papers include 2759 and 9156 papers in Eur. J. Pain and PAIN®, respectively. Currently, there are 24 active 'pain' journals. Authors/paper increase from 2 to 7 indicating a development from mono-disciplinary to multi-disciplinary studies. The overall publication profiles assessing preclinical, human (experimental/clinical) and translational papers in Eur. J. Pain and PAIN® were almost similar (14%, 75% and 10% versus 26%, 63% and 10%). Papers have changed over the years from mono-disciplinary studies (e.g. behavioural studies) to multi-disciplinary studies (e.g. combined behavioural and cell studies). After optimization, the search model matched the manual screening by 100%, 98% and 96% for the preclinical, clinical and healthy volunteer categories.

CONCLUSIONS

Over the last 45 years, more than 60,000 pain-related papers have been published. Papers develop over the years from mono-disciplinary to multi-disciplinary studies. The overall publication profile including preclinical, human (experimental/clinical) and translational papers was almost similar in Eur. J. Pain and PAIN®.

SIGNIFICANCE

The bibliometric analysis of a pain journal provides information on which specific areas of research are published, how this may have changed over the years and how a journal is positioned compared with other journals in the field.

Exo-Ocean Exploration with Deep-Sea Sensor and Platform Technologies

One of Saturn's largest moons, Enceladus, possesses a vast extraterrestrial ocean (i.e., exo-ocean) that is increasingly becoming the hotspot of future research initiatives dedicated to the exploration of putative life. Here, a new bio-exploration concept design for Enceladus' exo-ocean is proposed, focusing on the potential presence of organisms across a wide range of sizes (i.e., from uni- to multicellular and animal-like), according to state-of-the-art sensor and robotic platform technologies used in terrestrial deep-sea research. In particular, we focus on combined direct and indirect life-detection capabilities, based on optoacoustic imaging and passive acoustics, as well as molecular approaches. Such biologically oriented sampling can be accompanied by concomitant geochemical and oceanographic measurements to provide data relevant to exo-ocean exploration and understanding. Finally, we describe how this multidisciplinary monitoring approach is currently enabled in terrestrial oceans through cabled (fixed) observatories and their related mobile multiparametric platforms (i.e., Autonomous Underwater and Remotely Operated Vehicles, as well as crawlers, rovers, and biomimetic robots) and how their modified design can be used for exo-ocean exploration.

Can combining vaginal and rectal progesterone achieve the optimum progesterone range required for implantation in the HRT-FET model?

RESEARCH QUESTION

What is the ongoing pregnancy rate (OPR) in frozen embryo transfer (FET) cycles, using combined rectal and vaginal progesterone in hormonal replacement therapy (HRT)?

DESIGN

A prospective cohort study (n = 277) including 239 HRT-FET cycles with serum progesterone measurements studying combined vaginal (90 mg/12 h) and rectal (90 mg/12 h) progesterone administration and single blastocyst transfer on the sixth day of progesterone administration. A total of 134 responses to questionnaires covering convenience and side-effects were collected.

RESULTS

The median serum progesterone level was 45 nmol/l (range 2-150 nmol/l). Overall positive HCG rate, OPR at week 12 and pregnancy loss rates were 62%, 44% and 29%, respectively. A non-linear relationship between serum progesterone levels and OPR was found. Crude odds ratio for OPR in the high progesterone group (>45 nmol/l) was 0.56 (95% CI 0.32 to 0.98; P = 0.04) compared with the intermediate progesterone group (28-45 nmol/l). Discomfort after rectal progesterone administration was reported on the embryo transfer day and on the day of pregnancy scan 5 weeks later by a total of 18% (16/87) and 17% (8/47) of patients, respectively. Discomfort related to vaginal administration increased significantly over time and was reported by 18% (16/87) on the day of embryo transfer compared with 45% (21/47) on the day of pregnancy scan (P < 0.002).

CONCLUSIONS

Combined rectal and vaginal progesterone in HRT-FET cycles resulted in higher median progesterone levels compared with vaginal administration alone. This study suggests that an upper threshold for serum progesterone exists and that above this concentration serum progesterone levels decrease the OPR. Rectally administered progesterone was well tolerated by patients.

Orientation and stability of a bi-functional aromatic organic molecular adsorbate on silicon

In this work we combine scanning tunneling microscopy, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission spectroscopy and density functional theory to resolve a long-standing confusion regarding the adsorption behaviour of benzonitrile on Si(001) at room temperature.

Gastric neuroendocrine tumors: prevalence in Europe, USA, and Japan, and rationale for treatment with a gastrin/CCK2 receptor antagonist

OBJECTIVE

Gastric carcinoids (neuroendocrine tumors) arise from enterochromaffin-like cells in the gastric mucosa. Most are caused by hypergastrinemia. The objectives were to determine if their prevalence in Europe, USA and Japan meets the criteria for an orphan disease and to justify treatment with a gastrin/CCK2 receptor antagonist.

METHODS

We obtained data from European and USA cancer registries, and searched PubMed.

RESULTS

Prevalence per 10,000 population obtained from cancer registries was: median 0.32 (range 0.09-0.92) for Europe; and 0.17 for the USA, equivalent to 4812 for the whole population. A PubMed search for gastric carcinoids yielded prevalence for Japan only, which was 0.05 per 10,000 population, equivalent to 665 for the entire population. A further search for gastric carcinoids in patients with pernicious anemia (PA) or autoimmune chronic atrophic gastritis (CAG), two presentations of about 80% of gastric carcinoids, produced prevalence rates of 5.2-11%. Prevalence of PA itself was 0.12-1.9%. Data on CAG epidemiology were sparse.

CONCLUSION

Prevalence of gastric carcinoids varied widely. All sources probably underestimate prevalence. However, prevalence was below the limits required for recognition by drug regulatory authorities as an orphan disease: 5 per 10,000 population of Europe; 200,000 for the whole population of the USA; and 50,000 for the whole population of Japan. Because gastric carcinoids are an orphan disease, and nonclinical and healthy volunteer studies support treatment with netazepide, a gastrin/CCK2 antagonist, netazepide has been designated an orphan medicinal product in Europe and the USA for development as targeted treatment for gastric carcinoids.

[Complex fracture-dislocation of the proximal interphalangeal joint. A case report and focus on palmar proximal interphalangeal fractures-dislocations]

The palmar fracture-dislocation of the proximal interphalangeal (PIP) joint of fingers is an uncommon injury. We report a complex form in a 16-year old teenager, associating a palmar fracture-dislocation and a fracture of the base of the middle phalanx with the dorsal fragment dislocated between the neck of the proximal phalange and the palmar plate. The management was surgical with open reduction and fixation of the fragments by K-wires and temporary PIP arthrorisis. The result at 6months of follow- up after removal of the wires and physiotherapy was satisfactory. The patient was painless with a range of motion of 115°. Clinically, the sagittal and frontal stability of the joint both in flexion and extension was maintained. Osseous healing was obtained on X-ray control. The patient went back to his usual activities. A focus on palmar fracture-dislocations of PIP joint is presented through incidence, mechanism and treatment.

[Incidence of painful neuroma after end-to-end nerve suture wrapped into a collagen conduit. A prospective study of 185 cases]

Three to 5% of the nerves directly and correctly sutured evolve towards significant neuropathy pain. The psychological, social and economic impact of such a consequence is very important. The purpose of this retrospective study was to evaluate the incidence of the occurrence of a trigger zone or a neuroma, at 6months of maximum follow-up after direct nervous suture bushed in a type 1 collagen tube. Every patient taken care for a traumatic nervous injury from November 2008 to March 2012 was included in the study. The exclusion criteria were any replantation, nervous tissue defect and any distal nervous stump which could not technically be wrapped around. The only conduct used was made of collagen type 1 (Revolnerv(®), Orthomed™). All patients were examined after one, three and sixmonths for a clinical evaluation made by the same surgeon. The apparition of a trigger zone or a real neuroma was clinically assessed. One hundred and seventy-four patients for a total of 197 sutured nerves were included in the study. At the 6 months follow-up, 163 patients were evaluated for a total of 185 nerves. No patient suffered from a neuroma at this time. As the treatment of neuroma is very difficult, considering the cost and the results, wrapping direct end-to-end sutures by a collagen type 1 tube seems helping to prevent the appearance of a neuroma.

Lesions of the scapholunate ligament associated with minimally displaced or non-displaced fractures of the scaphoid waist. Which incidence?

INTRODUCTION

It was commonly considered that a non-displaced or minimally displaced isolated scaphoid fracture was mechanically incompatible with a lesion of the scapholunate ligament (SL). However, some authors who described such an association have recently challenged this statement. The aim of this prospective study was to determine, after screw fixation and using arthroscopy, the existence and incidence of lesions of the SL as associated with acute non-displaced or minimally displaced isolated fractures of the scaphoid.

METHODS

Between December 2009 and January 2011, the study included all patients presenting with an acute non-displaced or minimally displaced isolated fracture of the scaphoid waist, eligible for percutaneous screw fixation and accepting the procedure after informed consent. The surgical protocol included a first retrograde arthroscopically controlled percutaneous screwing of the scaphoid, followed by a second arthroscopy seeking only lesions of the SL. Geissler's classification was used for the classification of SL lesions.

RESULTS

Eighteen patients were included in the study. The mean was 29 years. In 17 cases, the scaphoid fracture was due to a low-energy fall, and in 1 case, to a road accident. No SL lesion was evidenced by the diagnostic arthroscopy.

CONCLUSION

Unlike some published reports, we did not observe any SL lesion associated with non-displaced or minimally displaced isolated fractures of the scaphoid. Nevertheless, despite such results and based on the literature, we recommend arthroscopy with percutaneous scaphoid screw fixation, with the triple advantage of providing reduction control, adequate screw fixation verification, and diagnosis of potential associated ligament lesions.

Dissection of stromal and cancer cell-derived signals in melanoma xenografts before and after treatment with DMXAA

Background:

The non-malignant cells of the tumour stroma have a critical role in tumour biology. Studies dissecting the interplay between cancer cells and stromal cells are required to further our understanding of tumour progression and methods of intervention. For proof-of-principle of a multi-modal approach to dissect the differential effects of treatment on cancer cells and stromal cells, we analysed the effects of the stromal-targeting agent 5,6-dimethylxanthenone-4-acetic acid on melanoma xenografts.

Methods:

Flow cytometry and multi-colour immunofluorescence staining was used to analyse leukocyte numbers in xenografts. Murine-specific and human-specific multiplex cytokine panels were used to quantitate cytokines produced by stromal and melanoma cells, respectively. Human and mouse Affymetrix microarrays were used to separately identify melanoma cell-specific and stromal cell-specific gene expression.

Results:

5,6-Dimethylxanthenone-4-acetic acid activated pro-inflammatory signalling pathways and cytokine expression from both stromal and cancer cells, leading to neutrophil accumulation and haemorrhagic necrosis and a delay in tumour re-growth of 26 days in A375 melanoma xenografts.

Conclusion:

5,6-Dimethylxanthenone-4-acetic acid and related analogues may potentially have utility in the treatment of melanoma. The experimental platform used allowed distinction between cancer cells and stromal cells and can be applied to investigate other tumour models and anti-cancer agents.

Determining the orientation of a chiral substrate using full-hemisphere angle-resolved photoelectron spectroscopy

Chiral interfaces and substrates are of increasing importance in the field of enantioselective chemistry. To fully understand the enantiospecific interactions between chiral adsorbate molecules and the chiral substrate, it is vital that the chiral orientation of the substrate is known. In this Letter we demonstrate that full-hemisphere angle-resolved photoemission permits straightforward identification of the orientation of a chiral surface. The technique can be applied to any solid state system for which photoemission measurements are possible.

Percutaneous retrograde screw fixation of non-displaced fractures of the scaphoid waist: an antirotation wire may not be necessary

Some authors recommend using an antirotation wire when performing percutaneous screw fixation of acute non-displaced scaphoid waist fractures. The aim of this study of 21 cadaveric wrists was to assess the usefulness of such a wire in Herbert's B2-type fractures. A B2-type fracture was created experimentally on each scaphoid. An antirotation wire was inserted in eight wrists. Retrograde percutaneous fixation using a double-threaded headless cannulated screw was performed on all wrists. Computed tomography was used to measure interfragmentary rotation. No interfragmentary rotation was noted in either group. Our study suggests that using an antirotation wire may be unnecessary when performing retrograde percutaneous screw fixation of isolated B2-type scaphoid fractures.

Photoabsorption and photoemission of magnesium diboride at the Mg K edge

The Mg K edge photoabsorption spectrum and the B 1s, Mg 1s, Mg 2p and valence band photoemission spectra of polycrystalline magnesium diboride have been measured. The photoabsorption spectra of the diboride and the oxide, which is present as an impurity, were separated by measuring the Auger electron partial yield at electron energies characteristic of each phase. The spectra are consistent with published calculations of the density of unoccupied p symmetry states. Better agreement is obtained with calculations for the ground state of the system than with ones for the excited state. Valence band photoemission spectra were measured at photon energies corresponding to core resonances, but, within the signal to noise level of the spectra, no resonant enhancement was observed. This is consistent with the delocalized nature of the valence band.

Evolution of the nanomorphology of photovoltaic polyfluorene blends: sub-100 nm resolution with x-ray spectromicroscopy

We investigate the influence of annealing on the morphology of intimately mixed blends of the conjugated polymers poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylene-diamine) (PFB) and poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) with scanning transmission x-ray microscopy (STXM). Through the use of a zone plate with theoretical Rayleigh resolution of 30 nm, we are able to resolve sub-100 nm bulk structure in these films. Surprisingly, for unannealed films spin-coated from chloroform we observe features with an average diameter of 85 nm. The high degree of photoluminescence quenching in these as-spun films (>95%) implies that there is significant intermixing within the 85 nm structures, indicating that a hierarchy of phase separation exists even on the length scale of less than 100 nm. With annealing up to 160 °C, close to the T(g) of the components, there is little change in the feature sizes observed by STXM, although an increase in variation of the composition is observed. With annealing above 160 °C the imaged features begin to evolve in size, increasing to 225 nm in extent, alongside large changes in composition with annealing to 200 °C. Comparing the evolution of morphology imaged by STXM with the change in photoluminescence quenching with annealing, we propose that phase separation first evolves via the evolution of relatively pure phases on the length scale of a few to tens of nanometres within the larger 85 nm structures. Once the length scale of compositional fluctuations exceeds 85 nm (for anneal temperatures above 160 °C) the hierarchy of phase separation is lost and the subsequent morphological evolution is readily imaged by STXM. Applying the results of an exciton diffusion and quenching model, we find good agreement between the size of the domains measured by STXM (above 180 °C) and the results of the model for an exciton diffusion length of 15 nm. The growth in domain size and towards purer structures has also been observed with resonant soft x-ray scattering.

Diversity of entomopathogenic fungi near leaf-cutting ant nests in a neotropical forest, with particular reference to Metarhizium anisopliae var. anisopliae

We investigated the prevalence of entomopathogenic fungi associated with leaf-cutting ant colonies in a small area of tropical forest in Panama. There was a high abundance of Metarhizium anisopliae var. anisopliae near the colonies. Beauveria bassiana was also detected in the soil, Aspergillus flavus in dump material, and six Camponotus atriceps ants were found infected with Cordyceps sp. Based on a partial sequence of the IGS region, almost all of the M. anisopliae var. anisopliae isolates fell within one of the three main clades of M. anisopliae var. anisopliae, but with there still being considerable diversity within this clade. The vast majority of leaf-cutting ants collected were not infected by any entomopathogenic fungi. While leaf-cutting ants at this site must, therefore, regularly come into contact with a diversity of entomopathogenic fungi, they do not appear to be normally infected by them.

Intraspecific variation and host specificity of Entomophthora muscae sensu stricto isolates revealed by random amplified polymorphic DNA, universal primed PCR, PCR-restriction fragment length polymorphism, and conidial morphology

The intraspecific variations of Entomophthora muscae s. str. associated with particular host species, Musca domestica and Delia radicum, sampled from different localities and different years in Denmark and the variation of E. muscae s. str. originating from different host taxa were investigated. The isolates were compared both by primary spore morphology and by three molecular methods: random amplified polymorphic DNA, universal primed PCR, and PCR-restriction fragment length polymorphism. Analyses of the different molecular data showed the same overall picture and separated E. muscae s. str. into two main groups with all the M. domestica isolates in one group and isolates from D. radicum, Coenosia tigrina, and Pegoplata infirma in the second group. E. muscae s. str. isolates from M. domestica also differ significantly from the rest of the E. muscae s. str. isolates with regard to the morphology of the primary conidia, which were bigger and contained significantly more nuclei per conidium. Several different E. muscae s. str. genotypes were documented and each type was restricted to a single host species, indicating a very high degree of host specificity at or below the level of the subfamily.

Indazolylamino quinazolines and pyridopyrimidines as inhibitors of the EGFr and c-erbB-2

Described herein is the design and synthesis of indazolylaminopyridopyrimidines and quinazolines as inhibitors of the class 1 tyrosine kinase receptor family. Data is presented for N(4)-(1-benzyl-1H-indazol-5-yl)-N(6),N(6)-dimethylpyrido[3,4-d]pyrimidine-4,6-diamine 3B. This compound inhibited EGFr and c-erbB-2 enzymes selectively over other kinases. It inhibited the proliferation of a range of tumour cell lines in vitro and the growth of BT474 xenografts in SCID mice.

Intra-epithelial vaccination with COPV L1 DNA by particle-mediated DNA delivery protects against mucosal challenge with infectious COPV in beagle dogs

Protection against viral challenge with canine oral papillomavirus (COPV) was achieved by immunisation via particle-mediated DNA delivery (PMDD) of a plasmid encoding the COPV L1 gene to cutaneous and oral mucosal sites in beagle dogs. The initial dose of approximately 9 microg of DNA was followed by two booster doses at 6 week intervals. A similar approach was used to vaccinate a control group of animals with plasmid DNA encoding the Hepatitis B virus S gene. Following challenge at the oral mucosa with COPV all animals vaccinated with the COPV L1 gene were protected against disease. However five of six animals in the control group developed COPV induced papillomas at the oral mucosa. Both cell-mediated lymphoproliferative and humoral antibody responses to the DNA vaccine were observed. Our data indicate that PMDD of plasmid DNA can protect against mucosal challenge with papillomavirus.

Entomophthora muscae resting spore formation in vivo in the host Delia radicum

The formation in vivo of Entomophthora muscae resting spores was investigated in the host, Delia radicum (cabbage root fly), by analysis of field data on the seasonal occurrence of E. muscae resting spores over 4 years. E. muscae resting spores in D. radicum were spherical with an average diameter of 39.4 microm, and the average numbers produced were estimated at 5.7 x 10(4) resting spores/female cadaver. Resting spores were found only after midsummer in D. radicum and almost exclusively in females. The proportion of infected females with resting spores was negatively correlated with average weekly day length after midsummer. We did not detect any significant year effect; thus, the results support the hypothesis that the photoperiod is the most important abiotic factor controlling E. muscae resting spore formation in D. radicum.

LabPatch, an acquisition and analysis program for patch-clamp electrophysiology

An acquisition and analysis program, "LabPatch," has been developed for use in patch-clamp research. LabPatch controls any patch-clamp amplifier, acquires and records data, runs voltage protocols, plots and analyzes data, and connects to spreadsheet and database programs. Controls within LabPatch are grouped by function on one screen, much like an oscilloscope front panel. The software is mouse driven, so that the user need only point and click. Finally, the ability to copy data to other programs running in Windows 95/98, and the ability to keep track of experiments using a database, make LabPatch extremely versatile. The system requirements include Windows 95/98, at least a 100-MHz processor and 16 MB RAM, a data acquisition card, digital-to-analog converter, and a patch-clamp amplifier. LabPatch is available free of charge at http://www.fhs.mcmaster.ca/huizinga/.

The search for the origin of rhythmicity in intestinal contraction; from tissue to single cells

More than a century ago, rhythmic propulsive contractile activity was observed in the intestine after blockade of nerve conduction, thus demonstrating a form of peristalsis that appeared to be under myogenic control. During this century, light and electron microscopic investigations provided the hypothesis that interstitial cells of Cajal (ICC) could be the cells of origin for this rhythmicity. In recent years, physiological studies demonstrated a link between the presence of electrical slow wave activity and the presence of ICC. The recognition that the ICC cell membrane harbours the Kit protein sparked rapid advancement in ICC research, and has been essential in the identification of ICC in tissue and in culture through Kit immunohistochemistry and kit mRNA reverse transcriptase polymerase chain reaction (RT-PCR). With these techniques, electrophysiology was carried out on positively identified single ICC in culture. These methods revealed that single ICC generate spontaneous rhythmic inward currents and slow waves in membrane potential, thus providing strong evidence that ICC generate the electrical pacemaker activity for the gut musculature.

Interstitial cells of Cajal generate a rhythmic pacemaker current

Networks of interstitial cells of Cajal embedded in the musculature of the gastrointestinal tract are involved in the generation of electrical pacemaker activity for gastrointestinal motility. This pacemaker activity manifests itself as rhythmic slow waves in membrane potential, and controls the frequency and propagation characteristics of gut contractile activity. Mice that lack a functional Kit receptor fail to develop the network of interstitial cells of Cajal associated with Auerbach's plexus in the mouse small intestine and do not generate slow wave activity. These cells could provide an essential component of slow wave activity (for example, a biochemical trigger that would be transferred to smooth muscle cells), or provide an actual pacemaker current that could initiate slow waves. Here we provide direct evidence that a single cell, identified as an interstitial cell of Cajal by light microscopy, electron microscopy and expression of Kit mRNA, generates spontaneous contractions and a rhythmic inward current that is insensitive to L-type calcium channel blockers. Identification of the pacemaker of gut motility will aid in the elucidation of the pathophysiology of intestinal motor disorders, and provide a target cell for pharmacological treatment.

Morphological adaptations to induced changes in transepithelial sodium transport in chicken lower intestine (coprodeum): a study of resalination, aldosterone stimulation, and epithelial turnover

Transepithelial sodium transport and epithelial morphology during short-term adaptation to resalination or aldosterone stimulation were studied in the chicken coprodeum. Coprodeum was sampled for light and electron microscopy after 0-3 days of resalination in hens on a low-NaCl diet and after 0-6 days of aldosterone stimulation in hens on a high-NaCl diet. Sodium transport was measured in vitro with Ussing chambers. Plasma osmolality and electrolyte concentrations were measured in aldosterone-stimulated hens. Epithelial proliferation and migration between 1 h and 16 days were investigated in chickens on high-NaCl and low-NaCl diets using a bromodeoxyuridine technique. Resalination abolished the otherwise high sodium transport within 1 day, while the height and number of microvilli, as well as the number of brush cells, decreased over 3 days. Aldosterone stimulation increased sodium transport, the height and number of microvilli, and the brush-cell number. Bromodeoxyuridine studies indicated an epithelial cell turnover of more than 16 days. The results thus demonstrate that epithelial cells have an unusual capacity to adjust rap- idly to variations in sodium intake. A strong correlation between structure and function was apparent.

Synaptic communication between external and internal submucosal plexus neurones in the jejunum of the newborn pig?

Intracellular recordings were made from neurones in the internal submucosal plexus (ISP) of porcine small intestine and synaptic inputs were investigated by focal stimulation of nerve fiber tracts. Nicotinic fast excitatory potentials (e.p.s.p.s) were recorded in all neurones, but slow e.p.s.p.s and slow inhibitory potentials (i.p.s.p.s) were rarely seen. Membrane potential changes similar to those occurring during the slow e.p.s.p. and slow i.p.s.p. could be evoked by exogenous application of neurotransmitters, even in neurones failing to display a nerve-mediated response. We suggest that the predominant source of the slow synaptic inputs to the ISP may be the neurones of the external submucosal plexus (ESP). The failure to record slow e.p.s.p.s and i.p.s.p.s could be a consequence of the anatomical arrangement of the submucosal plexuses whereby interconnecting strands between the ISP and ESP are inaccessible to the focal stimulation.

Electrophysiological classification of submucosal plexus neurones in the jejunum of the newborn pig

Intracellular recordings were made from the internal and external submucosal ganglia of the porcine small intestine and neuronal properties were classified using two existing schemes for guinea-pig enteric neurones. In the first analysis, 77% of cells were designated as Type 4 since they were a heterogeneous population of neurones with the overlapping properties of S/Type 1 and AH/Type 2. The simplicity and usefulness of the second classification scheme was due to its emphasis on a single electrophysiological event, namely, the long-lasting after-hyperpolarization (AH) following the action potential. Eighty-eight percent of the cells studied were thus categorized as either AH (with an AH) or S (without an AH). All S neurones displayed fast synaptic potentials in response to stimulation of interganglionic fibre strands. AH neurones were subdivided into two groups dependent on whether they received fast synaptic inputs. Only by employing the second scheme of classification were differences in the neuronal characteristics and synaptic profiles between the two submucosal plexuses detected. It is concluded that the S and AH system of classification is the most appropriate method for the analysis of intracellular recordings from submucosal neurones in the porcine small intestine.

Electrophysiological properties of neurones in the internal and external submucous plexuses of newborn pig small intestine

1. Intracellular microelectrodes were used to identify three major electrophysiological categories of neurone in both the internal and external submucous plexuses of the porcine small intestine. 2. Two classes of neurone with a long-lasting after-hyperpolarization following their action potential were differentiated by the presence or absence of fast excitatory synaptic inputs (EPSPs) and were termed AH neurones. S neurones received fast EPSPs but did not display after-hyperpolarizations. 3. The mean resting membrane potentials of the three groups of neurones showed a similar trend in both plexuses, with significantly higher values for the two populations of AH neurone than for S neurones. No significant variation of input resistance with cell type was detected. Neuronal input resistance was significantly greater in the internal submucous plexus than in the external submucous plexus. 4. Over 80% of AH neurones in the internal submucous plexus displayed fast EPSPs but a similar percentage of AH neurones in the external submucous plexus did not show fast EPSPs. S neurones constituted 60% of cells studied in the internal submucous plexus but less than 30% of the cell population in the external submucous plexus. 5. This study of porcine submucous neurones has revealed both similarities and differences to previous work in the guinea-pig small intestine. The most contrasting features are the relative abundance and subclassification of AH neurones in the pig in addition to the apparent paucity of slow synaptic potentials. The differences in the neuronal profiles of the internal and external submucous plexuses may reflect a differentiation of function between the two enteric nerve networks.

Dissection of the external and internal submucous plexuses of the pig small intestine

The submucous plexus of large mammals like dog, horse, cow, sheep, pig and man consists of more than one easily identified plexus. The divisions of the submucous plexus are known as the external submucous plexus and the internal submucous plexus. Recently findings have shown that there exists functional differences between the neuronal populations in the subdivisions of the submucous plexus in the small intestine of pigs. We report here how to obtain whole mounts of the submucous plexus containing both the internal and the external submucous plexus. The whole mounts from the submucous plexus of the pig contains almost no muscle and can be used in intracellular neuronal studies without adding nifedipine or equivalent L-type Ca2+ channel blockers to inhibit the contractions of the smooth muscle.

Advanced computer control of electrophysiological experimentation

A special configuration of the data acquisition software package Spike2 (CED) has been developed to allow interactive computer control of a current-clamp intracellular recording system. Using the 1401plus dedicated computer (CED) as an interface between the electrophysiological apparatus and a personal computer it was possible to have keyboard-control of intracellular current injection, single and repetitive pulse nerve stimulation, pressure ejection as well as on-going data acquisition. An analysis program was designed using the Spike2 programming language for the investigation of resting membrane properties, spike characteristics and synaptic input profiles of enteric neurones. The hardware configurations and associated software of our set-up may be of interest to electrophysiologists wishing to implement or extend a computer-based experimental system.

Unsaturated fatty acids are the active molecules of a glucan-synthase-inhibitory fraction isolated from entomophthoralean protoplasts

A few entomophthoralean species are able to multiply in a protoplast form. The polysaccharide synthases which synthesize the cell wall are inactivated in this form. An inhibitor of one of the key enzymes of wall synthesis, glucan synthase, was isolated from entomophthoralean protoplasts, using silica column chromatography and HPLC. Thin-layer and gas chromatography revealed free fatty acids in the inhibitory fractions. These fatty acids, including long-chain unsaturated fatty acids, were shown to be responsible for the inhibition of glucan synthase. The fatty acids were generated during incubation of a protoplast homogenate for 36 h at 37 degrees C and were shown to be non-competitive and non-specific inhibitors of glucan synthase.

Cloning of two chitin synthase gene fragments from a protoplastic entomophthorale

Chitin synthase expression was studied in spontaneously produced protoplasts and in hyphal bodies of the Entomophthorale species Entomophaga aulicae. The absence of wall in protoplasts was correlated to an absence of chitin synthase. Two chitin synthase activities with different biochemical characteristics have been detected in the hyphal bodies. Two chitin synthase gene fragments EaCHS1 and EaCHS2 of 600 bp were obtained using PCR amplification of genomic DNA. Their amino acid sequences showed 75% identity. Compared with other fungal chitin synthases, they belong to class II. EaCHS1 and EaCHS2 were used to probe total RNA from E. aulicae hyphal bodies and protoplasts. A single transcript of 2.4 kb hybridized only with EaCHS1 in protoplasts and hyphal bodies.

Association between biosynthesis of nitric oxide and changes in immunological and vascular parameters in patients treated with interleukin-2

Hypotension is a dose-limiting side effect of interleukin-2 (IL-2) therapy. This may be due to increased biosynthesis of the potent vasodilator nitric oxide (NO) induced by cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), which are known to be generated during IL-2 therapy. We describe the relationship between NO biosynthesis and changes in immunological and vascular parameters during IL-2 therapy in 13 patients with metastatic cancer. Plasma concentrations of neopterin and nitrite plus nitrate (NOx) were higher in cancer patients prior to treatment compared with normal subjects (neopterin; 10.8 +/- 1.4 vs. 2.0 +/- 0.4 ng ml-1, P < 0.001: NOx; 45 +/- 6 vs. 28 +/- 2 microM, P < 0.005). Pretreatment TNF-alpha and IFN-gamma plasma concentrations were not significantly different in cancer patients from those in controls. During infusion of IL-2 (18 x 10(6) international units m-2 per day for 5 days) these parameters increased, reaching maximal concentrations at day 3 for IFN-gamma and day 5 for TNF-alpha, neopterin and NOx. The maximal induced NOx correlated with maximal TNF-alpha (r = 0.60, P < 0.04), IFN-gamma (r = 0.63, P < 0.02) and neopterin (r = 0.66, P < 0.01). As plasma NOx concentrations increased, systolic blood pressure fell, reaching a minimum at day 3 despite a continued rise in NOx concentrations. These changes were accompanied by a continuous increase in pulse rate throughout the infusion period. These findings indicate that induction of NO biosynthesis contributes to hypotension induced during IL-2 therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile acids of marsupials. 2. Hepatic formation of vulpecholic acid (1 alpha,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic acid) from chenodeoxycholic acid in a marsupial, Trichosurus vulpecula (Lesson)

Free vulpecholic acid (1 alpha,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic) is the major biliary component of the Australian opossum (Trichosurus vulpecula), accompanied only by a few percent of its taurine conjugate. In order to exclude a microbial involvement in its formation (i.e., secondary origin) four sets of experiments were performed. It was found that a) the level of vulpecholic acid remained unchanged in the bile of opossums fed with neomycin and kanamycin for 7 days prior to bile collection; b) it also remained unchanged after long bile drainage; c) in opossums prepared with biliary cannula, intraportally injected [24-14C]chenodeoxycholic acid was transformed to [24-14C]vulpecholic acid; and d) in a similar experiment, the detectable transformation of [1 alpha,2 alpha-3H2]cholesterol to vulpecholic acid was observed. In experiment c) 28-66% of the administered radioactivity was secreted in 2 h in the form of free biliary vulpecholic and chenodeoxycholic acids. Only a trace amount of the corresponding taurine conjugates (approximately 0.4%) was formed. Moreover, rapidly declining specific radioactivity of the unconjugated chenodeoxycholic acid indicated its probable participation in the native formation of vulpecholic acid.

Tightly spiral shaped bacteria in the human stomach: another cause of active chronic gastritis?

Tightly spiral shaped Gram negative bacteria were seen in the gastric biopsies obtained from two patients undergoing gastroscopy. Active chronic gastritis was present in both patients and one patient also had gastric ulceration. Attempts to culture the organism by a number of methods were unsuccessful but positive urease results were obtained in both patients. Both patients were treated with colloidal bismuth subcitrate. Biopsies taken after treatment showed resolution of infection and histological gastritis. These results suggest that Helicobacter pylori is not the only organism associated with chronic active gastritis in man.

The Na+/H+ exchange and H+ diffusion properties of human postmortem mucus: a comparison of gastric antral, gastric body, jejunal and ileal mucus

The stomach and small intestine are areas of major electrolyte and solute transport. Mechanisms of transport in these areas have been widely studied and basic understanding is available. However, the mucus that lines the stomach and intestine is an important layer whose properties and functions in electrolyte and solute transport are not well understood. In this study we examined the Na+/H+ exchange of mucus from the stomach body and antrum, the jejunum, and the ileum. Mucus from the stomach body and antrum is a cation exchanger, a property that aids the net unidirectional flux of H+ ions from parietal cells to lumen. In the jejunum and ileum, mucus is an anion exchanger, which may be important in solute transport and absorption in the small bowel. In both the stomach and small bowel, proton movement is slow, which helps maintain the uphill pH gradient across gastric mucus and the downhill pH gradient across small intestinal mucus.

Na+/H+ ion-exchange property of postmortem human gastric mucus. The effects of Campylobacter pylori infection and sucralfate

The effect of Campylobacter pylori infection and sucralfate treatment on the ion-exchange property of human gastric mucus from 17 human postmortem stomachs was investigated in an in vitro chamber. Of the 10 stomachs not infected with C. pylori mucus from 4 stomachs had a 'normal' Na+/H+ exchange capacity, whereas 6 were without a Na+/H+ exchange capacity. The Na+/H+ exchange capacity of the seven stomachs infected with C. pylori was half that of the four 'normal' uninfected stomachs. Sucralfate significantly improved the Na+/H+ exchange capacity of mucus from C. pylori-infected stomachs and from the uninfected stomachs without Na+/H+ exchange. This study shows that impairment of the Na+/H+ exchange capacity of gastric mucus is associated with C. pylori infection and that sucralfate improves the Na+/H+ exchange capacity of gastric mucus.

Ammonia produced by Campylobacter pylori neutralizes H+ moving through gastric mucus

We aimed to show that Campylobacter pylori infection increases the concentration of ammonia in the gastric mucus and alters the movement of H+ through the mucus. Mucus from uninfected and C. pylori-infected stomachs was collected at postmortem. Ammonia was measured enzymatically. The ammonia concentration in C. pylori-infected mucus was fourfold greater than in uninfected mucus. H+ movement experiments were carried out using an in vitro chamber, in which a layer of mucus separated a 0.1 M HCl solution from distilled H2O. The change in pH of the distilled H2O was measured over 30 min. A drop in pH was measured for uninfected mucus. A slight rise in pH was measured for C. pylori-infected mucus. We conclude that C. pylori infection is associated with reduced H+ movement through mucus and that this may be due to increased ammonia concentration within mucus.