Usefulness of laser-evoked potentials and quantitative sensory testing in the diagnosis of neuropathic spinal cord injury pain: a multiple case study.

STUDY DESIGN: A retrospective study. OBJECTIVES: The aim of this study was to investigate the contribution of laser-evoked potentials (LEPs) and quantitative sensory testing (QST) to the diagnosis of neuropathic pain in patients with spinal cord injury (SCI) and inconclusive magnetic resonance imaging (MRI) findings. SETTING: A multidisciplinary pain center. METHODS: QST (DFNS protocol) and Tm-YAG-laser stimulation of the skin were applied within the pain site corresponding with dermatomes of altered sensation. Available MRI scans were reviewed. RESULTS: Thirteen individuals (50±16 years) with SCI were examined. In four cases with no detectable neural lesion on MRI, all QST but three LEP were abnormal. In four patients with poorly defined spinal lesion on MRI, all QST but three LEP only were abnormal. In four cases where pain was not matching adequately with MRI lesions, all patients had abnormal LEP and QST. In one patient showing a spinal cord atrophy, LEP was normal but QST was abnormal. Findings supported the diagnoses at-level (n=5) and below-level (n=8) SCI pain. Spinothalamic tract function assessed by LEP was normal in three cases, but QST was abnormal in all cases. CONCLUSIONS: As QST is a psychophysical examination depending on patient cooperation, we suggest that the combination of QST and LEP might be a valuable diagnostic tool to detect lesions of the somatosensory system in a subgroup of patients with neuropathic spinal cord injury pain and inconclusive MRI findings.

Pain assessment according to the International Spinal Cord Injury Pain classification in patients with spinal cord injury referred to a multidisciplinary pain center.

STUDY DESIGN: This is a retrospective study. OBJECTIVES: The aim of this study was to investigate the epidemiology of pain types in patients with spinal cord injury (SCI) according to the International Spinal Cord Injury Pain (ISCIP) classification. SETTING: This study was conducted in a multidisciplinary pain center. METHODS: Socio-demographic and clinical data were examined and ISCIP classification was applied. RESULTS: Sixty-six individuals (51±13 years) with SCI had pain, a lesion older than 5 years in 67% and a pain history older than 5 years in 54% of patients. According to the ISCIP classification, nociceptive pain was present in 58% (musculoskeletal pain) and 3% (visceral pain) of the patients. At-level, below-level neuropathic pain and other neuropathic pain were observed, respectively in 53, 42 and 5% of patients. Unknown pain type was found in 8% of patients. Patients with complete lesions showed significantly more frequent neuropathic pain (P=0.021) and more frequent at-level SCI pain (P=0.00) compared with those with incomplete lesions. Patients with paraplegia had more often at-level pain (P=0.00), whereas patients with tetraplegia reported more often below-level pain (P=0.00). Patients had severe pain (mean intensity: 8.2 (±1.6) on a 0 to 10 numerical scale) and showed high grades of pain chronicity. Mild to severe depression and anxiety were present, respectively in 53 and 56% of patients. The health-related quality of life was low. CONCLUSION: The use of the ISCIP classification in a clinical setting is mirroring the very complex pain situation in patients with SCI referred to a multidisciplinary pain center, and it might be an important step for adequate pain therapy.

Short lasting transient effects of a capsaicin 8% patch on nociceptor activation in humans.

BACKGROUND: At high concentration, the TRPV-1 agonist capsaicin de-sensitizes nociceptors and reduces the intra-epidermal nerve density. METHODS: We investigated the effects of a 5 × 10 cm capsaicin 8% patch on C- and A-delta-nociceptor activation in ten healthy subjects before and at days 1-3-7-21 after patch application. Thermal thresholds, infrared thulium-YAG laser-evoked potentials (LEP) and heat pain (numeric rating scale, NRS, 0-10), electrically induced pain (10 pulses, 1.5-fold pain threshold intensity, five randomized series of 5-10-20-50-100 Hz), and axon-reflex flare (laser Doppler imaging) were recorded. RESULTS: Thermal hypoesthesia developed upon capsaicin 8% treatment. Warmth detection thresholds increased at day 1-3, heat pain thresholds were increased by about 2.6 °C after day 3, and laser-evoked heat pain remained significantly reduced for 7 days. Axon-reflex flare responses (days 1-3), but not supra-threshold electrically induced pain were significantly reduced by the capsaicin patch. CONCLUSIONS: Axonal nociceptor function assessed by electrical excitability tests supplements threshold tests of nociceptive endings. The differential analgesic effects of 8% capsaicin patches may be attributed to the kinetics of capsaicin and the different depth of nociceptive nerve fibres, yet, the time course does not match the long-lasting analgesia observed in neuropathic pain patients treated with the same patch. WHAT DOES THIS STUDY ADD?: Axonal nociceptor function assessed by supra-threshold electrical excitability tests did not coincide with capsaicin-induced transduction changes supplementing threshold measures of terminal nociceptor endings. Threshold measurements do not reflect the sustained effect of pain relief seen in neuropathic pain patients. Capsaicin-sensitive nociceptors responsible for spontaneous pain are either not specifically tested with currently available sensory stimulation protocols or have higher capsaicin sensitivity or slower recovery under neuropathic conditions.

Ultrastructural localization of microtubule-associated proteins (MAP) 1 in cilia of the respiratory tract.

The presence and localization of high molecular weight microtubule-associated proteins of the MAP 1 class in ciliated cells of porcine and rat respiratory tract was studied by immunoblotting and immunoelectron microscopy. Ciliary shafts of the porcine tracheal epithelium were isolated using a method that minimizes contamination of the preparation by other cellular fragments and fat. Immunoblotting with rabbit antibodies to bulk MAP 1 from hog brain clearly revealed the presence of anti-MAP 1-immunoreactive high molecular weight proteins of the MAP 1 size in these preparations. To localize MAP 1 proteins at the ultrastructural level, rat and porcine tracheal epithelia were embedded in LR White and subjected to immunogold electron microscopy. Anti-MAP 1-immunoreactive material was found at ciliary shafts and basal bodies, but not at basal feet or ciliary rootlets. Interestingly, the necklace region between the shaft and the basal body of the cilium was hardly reactive with anti-MAP 1 antibodies. This may indicate a reduced stability of ciliary microtubules in this region and could be an explanation why ciliary shafts in general break more easily there than elsewhere.

Light and electron microscopic identification of elastic, elaunin and oxytalan fibers in human tracheal and bronchial mucosa.

The elastic fiber system in the human tracheal and bronchial mucosa was studied by light and electron microscopy. Elastic fibers, elaunin fibers, and oxytalan fibers were discerned. These fibers were identified by means of their staining characteristics (elastica stains, methods for disulfide-groups) and on account of their fine structural morphology. Elastic fibers consist of elastin and few "elastic-fiber microfibrils". The relative amount of elastin (compared to the amount of elastic-fiber microfibrils) is large in elastic fibers but small in elaunin fibers. Oxytalan fibers - by contrast - are pure bundles of microfibrils. In the light microscope a well-defined elastic lamina separates the lamina propria and the submucosa of the normal mucous membrane. The elastic lamina is formed by coarse strands of longitudinally running elastic fibers. A delicate network of elastica-positive fibers is attached to the basement membrane of the epithelial layer (subepithelial elastic layer). A few of these elastica-positive fibers branch out, traverse the region of the thickened basement membrane, and insert into the basal lamina of the epithelium. A loose network of elastica-positive fibers is present both in the lamina propria and in the submucosa. Plates of cartilage, glandular epithelium, and bundles of smooth muscle cells are enveloped by delicate elastica-positive fibers. Electron microscopy shows the lamina elastica to be predominantly composed of elastic fibers, whilst elaunin fibers form the subepithelial elastic layer. Fibers penetrating the thickened basement membrane of the epithelium are identified as oxytalan fibers. All three types of fibers are present throughout the lamina propria and in the submucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Histochemistry of the extracellular matrix of aging hyaline cartilage.

Cartilage proteoglycans (PGs) exhibit marked structural changes with increasing age. There is an increase in small PGs rich in KS as compared to larger PGs rich in chondroitin sulfate (CS) with increasing age. In the present study investigations have been performed to obtain more detailed information about the distribution of different glycosaminoglycans (GAGs). Changes were observed in the interterritorial matrix by means of ultrastructural visualization of PGs with acridin orange. The changes in the ultrastructural organization of the interterritorial matrix of costal cartilage are followed by significant changes in its mechanical properties.

Lectin-binding affinities of the epithelium in the respiratory tract. A light microscopical study of ciliated epithelium in rat, guinea pig, and hamster.

Complex carbohydrate components of surface coat and secretory granules were investigated in the laryngo-tracheo-bronchial epithelium of 3 laboratory animals (rat, guinea pig, and Syrian hamster). 2 groups of epithelial cells were distinguished in the light microscope: ciliated cells and non-ciliated cells. The latter mainly represent secretory cells and are subdivided into serous and mucous secretory cells. Apical glycocalix: In the rat, ciliated cells possess a significant number of Con A, RCA I, and WGA receptors, and a smaller number of UEA I binding sites. In hamsters and in guinea pigs additional binding sites for HPA could be demonstrated. The apical glycocalix of the non-ciliated cells in the rat evince marked staining with RCA I, WGA, and HPA, and less intensive binding of UEA I. In guinea pigs and in hamsters, the presence of additional Con A receptors was noted. Basolateral glycocalix: The basolateral surface coat of ciliated and non-ciliated cells shows identical lectin binding affinities. In the rat, the basolateral glycocalix binds RCA I; in the guinea pig, in addition, positive staining with UEA I and HPA is observed; in the hamster, the basolateral surface coat is outlined by RCA I and HPA receptors. Secretory products: Secretory granules of mucous cells in the rat react with Con A, UEA I and HPA lectins. In guinea pigs, these substances also bind RCA I and WGA lectins. Mucous granules in the secretory cells of the hamster are positive for Con A, RCA I, and HPA lectins. Granules of non-ciliated serous cells of rats bind Con A, UEA I, and HPA lectins. In the guinea pig, this reaction is weaker for UEA I lectin but comparable for Con A and HPA binding. A positive reaction with RCA I lectin only is found in the serous secretory granules of the hamster.

Conservation of veins with preservation of viable endothelium.

The influence of cryoprotective agents on the endothelium of jugular veins of dogs was examined after silver staining on en face preparations. Comparatively low concentrations of Glycerol or DMSO caused distinct morphological changes. Quick-freezing of air-filled vessels by liquid nitrogen permitted reservation of vessels with vital endothelium and comparatively mild morphological changes. Such vessels could be replanted after quick thawing. 2-4 days thereafter the endothelium of the grafts contained nuclei stainable with hematoxilin. The area covered by this endothelium remained devoid of parietal thrombi 2-4 days after replantation. However, lyophilized vessels grafted under the same conditions, were covered by large mural thrombi 2-4 days after the grafting procedure and no endothelial cells were found histologically.

[Some aspects of biological membranes: concepts and techniques (author's transl)]. / Zum Aufbau der Zellmembranen: Methoden und Konzepte

Some of the abundant data on the structure of biological membranes are compiled in this short review, with particular emphasis on morphological techniques. The "fluid mosaic" model of biological membranes has rapidly gained importance as the fundamental concept. According to this model, protein particles swim in a lipid bilayer, whose molecules are ordered with their hydrophilic end outside and their hydrophobic tail inside the membrane. Proteins are spatially stabilized and actively moved by a submembranous net of fibrillar proteins. Information about the orientation of protein molecules within the bilayer is obtained by protein labelling with membrane impermeable compounds and subsequent gel-electrophoretic separation of the solubilized components. Freeze etching brings to light intramembranous particles which are probably segments of the membrane proteins that stand out from the plane of the split hydrophobic membrane interface. By this method the morphology of cell contacts, for example, can be analyzed and comprehended at a supramolecular level. Special techniques such as observation of both matching sites of the split membrane halves or deep etching (whereby the actual surface of membrane is exposed) may provide further valuable contributions to the rapidly expanding field of membranology.

The technique of taking brush biopsies of the nasal mucosa for electron microscopy.

Patients suffering from symptoms suggestive of a disorder of mucociliary clearance should be subjected to electron microscopic examination of the ciliated respiratory epithelium. Provided that all crucial points regarding technique and storage are adhered to, brush biopsy of the nasal mucosa is a reliable method facilitating the electron microscopical diagnosis of primary disorders of the ciliated epithelium.

Amianthoid (asbestoid) transformation: electron microscopical studies on aging human costal cartilage.

The present study reports on the fine structure of human costal cartilage at different ages in order to obtain information on the morphogenesis of amianthoid fibers. Our results reveal an overall increase of collagen fibril diameter with increasing age, even in areas with no signs of amianthoid transformation. Ultrastructural evidence is presented that this increase in diameter is due to a gathering of the preexisting collagen fibrils. The age-related change in collagen fibril diameter is paralleled by changes in the composition and ultrastructural appearance of cartilage proteoglycans (as revealed by acridine orange staining). Acridine-orange-positive filaments indicative for proteoglycans are markedly reduced in size with advancing age in centrally located regions of costal cartilage. Treatment with testicular hyaluronidase previous to acridine-orange staining leaves these small proteoglycan filaments unaffected. By contrast, the filaments visible after acridine-orange staining in the extracellular matrix near to the perichondrium are susceptible to hyaluronidase treatment. Infrequently, a sharp increase in collagen fibril diameter can be observed in territorial matrix areas of degenerating chondrocytes. This observation is conspicuous at ages of 10 and 20 years. Amianthoid transformation is characterized by the appearance of collagen fibrils strictly arranged in parallel. These amianthoid fibers are embedded in a matrix rich in small acridine-orange-positive filaments similar to the proteoglycan filaments observed in centrally located matrix regions. It can be concluded that extensive remodelling not only of the collagen fibrils but also of the cartilage proteoglycans is involved in the development of amianthoid transformation.

Intracellular axonemes within ciliated cells in the tracheal epithelium of domestic pigs.

Extended aggregates of intracellular axonemal derivatives can be seen within the apical cytoplasm of ciliated cells of apparently healthy domestic pigs. Such alterations were observed in 15 out of 20 animals. Complete (9 + 2) or incomplete (8 + 2 - 5 + 2) intracellular axonemes were found which sometimes arose from mature, irregularly arranged kinetosomes. In addition, bundles of single microtubules and microtubular pairs were found. In previous investigations on the ciliated epithelium of different mammals, intracellular axonemes were investigated only under pathological or experimental conditions. Our findings indicate that these alterations also occur in healthy animals. The extended aggregates of intracellular axonemal derivatives are more likely to be due to a failure of ciliary maturation than to a degradation of incorporated mature cilia.

[Catabolic processes in the rectal mucosa. Light and electron microscopic studies]. / Abbauvorgänge in der Rektumschleimhaut Licht- und elektronenoptische Untersuchungen

The phagocytosing activity of macrophages and fibrocytes of the lamina propria was examined by means of light and electron microscopy; the material had been obtained through 121 biopsies performed on patients ranging in age from 3 weeks to 43 years (113 taken from the rectum, 8 from the small intestine). The phagocytosing activity of the stroma has been known since the studies of v. Möllendorf, Clara, Patzelt, Maximov, Malatzkaya carried out on guinea pigs, rats, birds and a few human embryos. In recent years this problem has been raised again by some American authors. Our studies close the gap existing for the age group ranging from birth to the 16th year. It was demonstrated that the rate of this activity is much higher than hitherto assumed by Askar, Ekuan and Hill, Azzopardi and Evans. The authors discuss the reasons for these discrepancies in the finding, and the origin and composition of the substances ingested.