[Eye movements during normal reading and in dyslexia--review of the literature].
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Dyslexia↗
Biomedical subjects
J Ygge
Publications and source records attributed to J Ygge.
Cellular reactions on heparin surface-modified versus regular PMMA lenses during the first postoperative month. A double-masked and randomized study using specular microphotography.
Specular microscopy was used for investigation of cellular reactions on the intraocular lens (IOL) anterior surface of Heparin surface-modified (HSM) versus regular polymethylmethacrylate (PMMA) lenses (Pharmacia types 700C versus 700B, respectively). The double-masked randomized study included 53 patients investigated at 1 and 4 weeks postoperatively. Giant cells were only found on control lenses and more frequently at 4 weeks. Small cells were found on both lens types, but in a higher frequency on the control lenses. The number of small cells decreased during the first 4 weeks on both the control and HSM lenses. However, those control lenses that had giant cells on their surface showed an increase in the number of small cells during the same time. The results of the current study show that HSM lenses give rise to less postoperative inflammatory cellular reactions than regular PMMA lenses.
Aged↗
Neuronal loss in lumbar dorsal root ganglia after proximal compared to distal sciatic nerve resection: a quantitative study in the rat.
The effects of unilateral sciatic nerve resections at proximal (thigh) or distal (proximal calf) locations on L4-L6 dorsal root ganglion (DRG) neuronal numbers have been studied in adult rats. Proximal nerve resection gave rise to a mean DRG neuronal loss of 27%, whereas in distal lesions a mean cell loss of 7% was found. This difference in cell loss between proximal and distal sciatic nerve resections is highly significant (P less than 0.001).
Animals↗
Central projections of the rat radial nerve investigated with transganglionic degeneration and transganglionic transport of horseradish peroxidase.
Transganglionic degeneration and transganglionic transport of HRP were used for investigation of the spinal cord and brainstem projections from the superficial, cutaneous (SR) and deep, muscular (DR) branches of the radial nerve. The HRP study included a numerical and size analysis of labelled dorsal root ganglion (DRG) cells. In degeneration experiments the SR nerve was found to project somatotopically to laminae III-IV, but degeneration was also found in lamina I and inconsistently in lamina II. Transection of the DR nerve was found to give rise to a small amount of degeneration, which in "sham" operations was established to result from the skin injury during dissection of the DR nerve. With the HRP method, the SR nerve was found to project somatotopically to laminae I-IV, whereas the DR nerve projected more diffusely to the medial part of laminae V-VII. HRP application to the SR and DR nerves resulted in labelling of a mean of 1,024 and 310 DRG cells, respectively. These labelled neurons had a median cell area of 381 and 562 micron 2 for the SR and DR nerves, respectively, and both small and large cells were labelled in both types of experiments. In the lower brainstem, projections from the SR nerve were found only in the ipsilateral dorsal part of the main cuneate nucleus (MCN) with both methods. Brainstem projections from the DR nerve that were found only with the HRP method were found in the ipsilateral ventral part of the MCN together with a projection to the ipsilateral external cuneate nucleus. No projections were found to the central cervical nucleus. The present results indicate that cutaneous compared to muscular primary sensory neurons are much more prone to react with transganglionic degeneration after peripheral nerve transection. Furthermore, in the rat the SR nerve projects somatotopically, whereas the DR nerve does not. Both nerve branches are connected to small and large spinal ganglion cells, although the median cell area is larger in muscular neurons.
Afferent Pathways↗
Substance P-, somatostatin- and calcitonin gene-related peptide-like immunoreactivity and fluoride resistant acid phosphatase-activity in relation to retrogradely labeled cutaneous, muscular and visceral primary sensory neurons in the rat.
The distribution of several peptides in cutaneous, muscular and visceral primary sensory neurons was investigated in the adult rat. The fluorescent dye Fast blue was applied to the proximal ends of transected saphenous (cutaneous), gastrocnemius (muscular) and greater splanchnic (visceral) nerves. Sections from corresponding dorsal root ganglia were incubated for simultaneous indirect immunocytochemical demonstration of calcitonin gene-related peptide (CGRP)-, substance P (SP)- or somatostatin (SOM)-like immunoreactivity (-LI) and Fast blue. In addition, the presence of fluoride resistant acid phosphatase (FRAP)-enzyme activity (-EA) in retrogradely Fast blue-labeled saphenous and gastrocnemius nerves was investigated by subsequent enzyme cytochemical analysis. The results revealed the presence of CGRP-LI, SP-LI, SOM-LI and FRAP-EA in cell bodies of primary sensory neurons which project to the saphenous and gastrocnemius nerves. CGRP-LI and SP-LI, but not SOM-LI, were found in splanchnic sensory neurons. The vast majority of the visceral sensory neurons were found to contain CGRP-LI.
Acid Phosphatase↗
A quantitative study of the effects of neonatal capsaicin treatment and of subsequent peripheral nerve transection in the adult rat.
The effects of unilateral intercostal nerve transection have been studied in adult rats neonatally treated with capsaicin. Two rats were treated with capsaicin-free vehicle and served as controls. It is shown that capsaicin treatment leads to a dorsal root ganglion cell loss of about 43%, and about a 72% loss of unmyelinated dorsal root fibers. Myelinated dorsal root fibers remain unaffected. The cell size spectrum shows a 27% increase in median cell area in the capsaicin-treated rats, indicating a loss of preferentially smaller cells. A subsequent peripheral nerve transection resulted in a further cell loss of about 30% with no major change in cell size spectrum. The peripheral nerve transection also somewhat further reduces both the number of unmyelinated and myelinated dorsal root axons. The data indicate that neurons which die after a peripheral nerve transection belong to both the groups of cells, which are capsaicin-sensitive and capsaicin-resistant.
Animals↗
Cell loss in lumbar dorsal root ganglia and transganglionic degeneration after sciatic nerve resection in the rat.
The effects of sciatic nerve resection on lumbar dorsal root ganglion cells and their central branches have been studied in the adult rat. A quantitative analysis of the lumbar dorsal root ganglia indicated a 15-30% cell loss on the operated side. Argyrophilia indicating transganglionic degeneration was observed in Fink-Heimer stained sections from the lumbar spinal cord and the brainstem. The areas of degeneration argyrophilia were mainly located in the medial part of the ipsilateral L2-L6 dorsal horn laminae I-IV, the tract of Lissauer, the dorsal funiculus and the gracile nucleus. A few degenerating fibers could also be observed in the ipsilateral dorsal horn laminae V and VI, and in the ipsilateral ventral horn as well as in the contralateral dorsal horn and the gracile nucleus. The results confirm and extend previous findings at other levels and in other species. This suggests that cell loss and transganglionic degeneration may be general phenomena affecting a substantial proportion of primary sensory neurons following peripheral nerve injury.
Animals↗
Separate populations of primary sensory neurons project to the splanchnic nerve and thoracic spinal nerve rami of the rat. A fluorescent double labelling study.
Using fluorescent double labelling technique with one tracer applied to the greater splanchnic nerve and a second to the ventral or dorsal spinal nerve ramus at the T9 level, it was shown that two separate populations of sensory nerve cell bodies in the T9 dorsal root ganglion were projecting to the splanchnic nerve and spinal rami, respectively. Only two double labelled cells were detected. The results support the theory that spinal and/or supraspinal interactions and not dichotomizing sensory axons are responsible for referred pain.
Animals↗
Peripheral projections and neuropeptide coexistence in a subpopulation of fluoride-resistant acid phosphatase reactive spinal primary sensory neurons.
Combined retrograde axonal tracing with the fluorescent dye Fast Blue and fluoride-resistant acid phosphatase (FRAP) histochemistry revealed that the FRAP-containing sensory neurons project to both somatic and autonomic peripheral nerves. Furthermore, the combination of indirect immunohistochemistry after colchicine treatment and FRAP histochemistry showed that a population of FRAP-containing sensory neurons are also substance P, cholecystokinin or somatostatin positive.
Acid Phosphatase↗
On the organization of the thoracic spinal ganglion and nerve in the rat.
The location of spinal ganglion cells projecting into various thoracic spinal nerve branches in the rat has been investigated using retrograde transport of horseradish peroxidase (HRP). In addition, total numbers of myelinated and unmyelinated axons in three consecutive pairs of thoracic spinal nerves have been analyzed. The animals were perfused one to 2 days after application of HRP to thoracic spinal nerve branches and several ipsilateral spinal ganglia sectioned and processed for HRP histochemistry. Labeled cells were found in ganglia corresponding to the level of operation, as well as several adjacent rostrally and caudally located ganglia. No somatotopic organization was found within the ganglia, but occasionally a clustering of labeled cells belonging to the same peripheral nerve was observed. Pieces from three consecutive pairs of ventral and dorsal spinal nerve rami were removed from two normal rats and embedded in Vestopal. Semithin sections including the entire cross-sectional area of the rami were used to count the total number of myelinated axons. The number of unmyelinated axons was estimated by sample counting in the electron microscope. The ventral ramus of the spinal nerve contained about twice as many axons and a lower proportion of unmyelinated fibers in comparison with the dorsal ramus. Large differences in the number of axons between the two sides in pairs of spinal nerve rami and entire spinal nerves were found. These differences diminished when comparing the total number of axons from three consecutive rami or nerves on each side.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Intercostal nerve transection and its effect on the dorsal root ganglion. A quantitative study on thoracic ganglion cell numbers and sizes in the rat.
The effect of intercostal nerve transection on the number and size distribution of thoracic spinal ganglion cells has been investigated and correlated with transganglionic degeneration (TGD) in the spinal cord dorsal horn. Unilateral transections were made of 3 or 11 consecutive intercostal nerves. Twenty to 180 days later the animals were perfused and relevant ganglia from both sides embedded in resin, serially sectioned and stained. Counts of neuronal nucleoli were made and perikaryal areas of ganglion cells measured. The number of neurons was significantly reduced on the operated side 20 days postoperatively. The cell loss increased slightly to about 35% with longer survival times. Analysis of cell size spectra showed a bilaterally symmetrical picture in normal animals. No distortions of the cell size spectrum were observed at 20 to 70 days after nerve transections. Transganglionic degeneration was found in the dorsal horn from 20 to 70 days postoperative survival, but not at 180 days. The findings indicate that TGD in the dorsal horn is related to a loss of ganglion cells in the corresponding spinal ganglion. There does not seem to be a preferential loss of any particular size class of cells.
Animals↗
The organization of the thoracic spinal nerve projection in the rat dorsal horn demonstrated with transganglionic transport of horseradish peroxidase.
Transganglionic transport of horseradish peroxidase (HRP) was used to study the organization of the thoracic spinal nerve projection to the dorsal horn in rats. Labeling was found in the superficial dorsal horn 16-20 hours after application of HRP to the cut ends of various spinal nerve rami. Labeling was restricted to the outer part of the substantia gelatinosa at these stages. Longer survivals (25-48 hours) gave rise to labeling of the deep part of substantia gelatinosa and deeper parts of the dorsal horn as well. The dorsal ramus projected to the lateral third of the horn from half a segment rostral to half a segment caudal to the entry segment. The ventral ramus projected to the medial two-thirds of the horn from 1 1/2 segments rostral to half a segment caudal to the entry segment. The two branches of the ventral ramus that were examined projected to separate medial and lateral compartments for the entire ventral ramus. There was a distinct lateromedial shift of the projection found from rostral through caudal levels within the projection compartment for each nerve. The results indicate that the dorsal horn projection of thoracic spinal nerve branches is organized in longitudinal compartments which are arranged in a strictly somatotopic fashion.
Animals↗
Somatotopic organization of the thoracic spinal nerve in the dorsal horn demonstrated with transganglionic degeneration.
Transganglionic degeneration in primary sensory neurons (TGD) has been studied with the Fink-Heimer and cupric silver methods in the adult rat after transection of thoracic spinal nerve branches. Degeneration was found in the ipsilateral dorsal horn after 13 to 53 days postoperative survival. It was observed in laminae III and IV, inconsistently in lamina I, but not in lamina II (substantia gelatinosa). After transection of the dorsal ramus of the spinal nerve degeneration was seen in the lateral third of the laminae. Transection of the intercostal nerve (ventral ramus) at about the costal angle gave rise to degeneration in the medial two-thirds and transection more distally, at about the mid-clavicular line, in the most medial part of the dorsal horn. The results are in accordance with previous anatomical and physiological studies of the somatotopical organization of the dorsal horn. They clearly show the usefulness of TGD as a tool for analysis of central projections of primary sensory neurons.
Afferent Pathways↗
Asymmetries and symmetries in the number of thoracic dorsal root ganglion cells.
The right/left ratio for the number of neurons in individual pairs as well as series of pairs of normal rat and guinea pig thoracic dorsal root ganglia have been investigated. After perfusion of the animals with aldehyde fixatives, the 13 pairs of thoracic ganglia were embedded in resin, serially sectioned, and stained with azure methylene blue. Counts of neuronal nucleoli (with correction for possible split nucleoli) were used as an indicator of the number of neurons in each ganglion. In individual pairs the right/left difference varied between 0 and 47% in the rat and 0 and 26% in the guinea pig. There appeared to be no particular level with a preference for large right/left differences. However, when the total number of neurons from the 13 ganglia on one side were compared with the corresponding figure from the other side, the right/left differences were reduced to less than 3% in the rat and less than 2% in the guinea pig. These results show that the organization of the thoracic spinal nerve unit is markedly asymmetrical at the segmental level, but strictly symmetrical in terms of the total number of dorsal root ganglion cells. The marked asymmetry in individual ganglion pairs necessitates caution when evaluating the effect of unilateral experimental manipulations on the number of neurons in thoracic spinal ganglia.
Animals↗
[Transient cerebral ischemic attacks. Treatment program and comparison between anticoagulants and thrombocyte aggregation repressors].
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Aged↗
Transganglionic transport of horseradish peroxidase in primary sensory neurons.
The cut end of the sciatic nerve of adult rats was exposed to horseradish peroxidase (HRP). The rats were allowed to survive for 12 h--5 days. 12--18 h postoperatively small dorsal root ganglion cells more heavily labeled than large ones. After 48--72 h more large cells were intensely labeled. From 18 h onwards large amounts of HRP labeling was observed ipsilaterally in the superficial laminae of the dorsal horn, from 48 h also in deeper laminae and in the gracile nucleus. The heavy labeling clearly indicates the potential of the present approach for mapping purposes. The findings also indicate that short postoperative survivals can be used for rather selective marking of small cells and fibers.
Animals↗
[Acute heparin therapy--standard dose or dosage according to individual sensitivity?].
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Aged↗
[Tumor at the epiphyseal site causing pheochromocytoma-like symptoms].
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Adolescent↗