Echt Violet Research Articles

Histopathological Effects of Titanium Dioxide Nanoparticles on the Broiler Chickens’ Brain Tissue

Background: Considering Titanium Dioxide Nanoparticles' (TiO2NPs) widespread use in industries such as food and cosmetics industries with increasing daily demand. The aim of the current study was to evaluate the TiO2NPs' teratogenic effects on the chick's brain tissue. Methods: Ninety fertilized eggs on the third day of incubation were equally divided into 5 groups of control, and intraovarian injection of TiO2NPs concentrations at 12.5, 25, 50, and 100 μg/ml. The chicks' survival rate and weight measurements were evaluated after 21 days. The cerebrum and cerebellum samples were analyzed after staining with Hematoxylin-Eosin, and Luxol Fast Blue-Cresyl Echt Violet. Results: Macroscopic and histomorphometric analyses revealed no significant differences between the groups. No statistically significant differences were observed in the weights of the brains of chicks. In group one the survival rate was 85.71%, group two 71.42%, group three 64.28% and group four 50%. Four cases of omphalocele and non-absorption of the yolk sac were observed in the group treated at 100 μg/ml. There were no statistically significant differences regarding the perivascular space of the cerebrum, neurons with Nissl bodies, the length of the cortex and medulla of the cerebellum, and the number of Purkinje cells, formation of myelin and pathological lesion. Conclusion: The finding of the current study demonstrates that the effects of TiO2NPs tend to be dose-dependent, posing a considerable danger in terms of embryonic tissue development. Further research endeavors could follow to explore more extensively, especially in the context of humans and the environment.

The neuroprotective effect of exogen melatonin upon fetal hippocampus damage caused by high-dose caffeine administration in pregnant rats.

The aim of this study is to evaluate whether exogenous melatonin (MEL) mitigates the deleterious effects of high-dose caffeine (CAF) administration in pregnant rats upon the fetal hippocampus. A total of 32 adult Wistar albino female rats were divided into four groups after conception (n = 8). At 9-20 days of pregnancy, intraperitoneal (i.p.) MEL was administered at a dose of 10mg/kg/day in the MEL group, while i.p. CAF was administered at a dose of 60 mg/kg/day in the CAF group. In the CAF plus MEL group, i.p. CAF and MEL were administered at a dose of 60 and 10mg/kg/day, respectively, at the same period. Following extraction of the brains of the fetuses sacrificed on the 21st day of pregnancy, their hippocampal regions were analyzed by hematoxylin and eosin and Cresyl Echt Violet, anti-GFAP, and antisynaptophysin staining methods. While there was a decrease in fetal and brain weights in the CAF group, it was found that the CAF plus MEL group had a closer weight average to that of the control group. Histologically, it was observed that the pyramidal cell layer consisted of 8-10 layers of cells due to the delay in migration in hippocampal neurons in the CAF group, while the MEL group showed similar characteristics with the control group. It was found that these findings decreased in the CAF plus MEL group. It is concluded that high-dose CAF administration causes a delay in neurogenesis of the fetal hippocampus, and exogenous MEL is able to mitigate its deleterious effects.

Mapping the avian visual tectofugal pathway using 3D reconstruction.

Image processing in amniotes is usually accomplished by the thalamofugal and/or tectofugal visual systems. In laterally eyed birds, the tectofugal system dominates with functions such as color and motion processing, spatial orientation, stimulus identification, and localization. This makes it a critical system for complex avian behavior. Here, the brains of chicks, Gallus gallus, were used to produce serial brain sections in either coronal, sagittal, or horizontal planes and stained with either Nissl and Gallyas silver myelin or Luxol fast blue stain and cresyl echt violet (CEV). The emerging techniques of diffusible iodine-based contrast-enhanced computed tomography (diceCT) coupled with serial histochemistry in three planes were used to generate a comprehensive three-dimensional (3D) model of the avian tectofugal visual system. This enabled the 3D reconstruction of tectofugal circuits, including the three primary neuronal projections. Specifically, major components of the system included four regions of the retina, layers of the optic tectum, subdivisions of the nucleus rotundus in the thalamus, the entopallium in the forebrain, and supplementary components connecting into or out of this major avian visual sensory system. The resulting 3D model enabled a better understanding of the structural components and connectivity of this complex system by providing a complete spatial organization that occupied several distinct brain regions. We demonstrate how pairing diceCT with traditional histochemistry is an effective means to improve the understanding of, and thereby should generate insights into, anatomical and functional properties of complicated neural pathways, and we recommend this approach to clarify enigmatic properties of these pathways.

SPARC: Distribution of Intrinsic Cardiac Neurons in 3D Reconstructed Hearts of F344 Rat

The intrinsic cardiac nervous system (ICN) is involved in the autonomic control of the heart and functions as an integrative center for local sensory and extrinsic autonomic inputs. There has been increasing interest in the functions of ICN neurons as well as their ablation as a therapeutic intervention for atrial fibrillation. The goal of the present study is to assess the distribution of ICN neurons between individuals with rat as a model using a novel data acquisition pipeline combining Knife Edge Scanning Microscope (KESM) with the custom software developed by MBF (Tissue Mapper) to perform single cell mapping of ICN neurons in 3D reconstructed rat hearts. Fischer 344 male rats (n = 3) were perfused through the abdominal aorta and whole‐mount perfusion stained with Cresyl Echt Violet. The hearts were then embedded into paraffin and mounted onto a robotic XYZ stage for simultaneous sectioning and imaging by a KESM. Individual section images that consisted of 1400, 1570, and 2580 sections for each heart that was cut at a 5 μm thickness were assembled into an image stack for anatomical cardiac digitization and single cell mapping of ICN neurons in Tissue Mapper for 3D heart reconstruction. The distribution of ICN neurons between individuals was assessed in two different planes of section: parallel sections showing 4‐chambers, and cross sections perpendicular to the long axis of the heart. The number of neurons counted in each of the heart samples were 2676, 2973, and 2885, with an average of 2844/rat. ICN neurons mainly localized around the posterior surface of the left and right atria and the hilum ‐ pulmonary veins, interatrial septum, along the pulmonary artery, and the root of the superior vena cava. We performed computational analysis of ICN neuron distribution using a partial projection approach based on principal component analysis of the 3D coordinates. We analyzed the first two principal components to compute a distribution of packing density in the 2D projection corresponding to maximum variability in the spatial location of single neurons. In parallel, we conducted unsupervised clustering of 3D coordinates of single neurons using partitioning around medoids algorithm and annotated the packing density distributions and 3D ICN neuron maps with the resultant clusters. Our analysis revealed that the density distribution, numbers of clusters and orientation of ICN neurons were similar across males with 7–10 clusters within each ICN. This demonstrates the robustness of the technique where single ICN neurons were well‐preserved and they localized around the same regions despite variation in section orientation. Thus, this technique can potentially be applied to study the distribution of ICN neurons in 3D reconstructed hearts of large animals and humans as well as to examine the sex differences and diseased‐induced remodeling of the ICN for future studies.Support or Funding InformationThis work is supported by NIH SPARC Program, grant #3OT2OD023848‐01 (PD/PI: K. Shivkumar; Subaward PIs: J. S. Schwaber, R. Vadigepalli, and Z. J. Cheng)

The distribution of serotonergic nerve on the hippocampus of the fruit bats (Rousettus amplexicaudatus).

Background:Rousettus amplexicaudatus is one of the old world fruit bats, commonly known in Javanese word as codot belongs to Order Chiroptera and suborder Megachiroptera. R. amplexicaudatus possessed an outstanding visual ability, which helps in the process of searching for food. Those activities process and save within the brain involving the learning and memory activities. Learning and memory activities are centered around the hippocampus with the help of serotonergic nerve.Aim:This study conducted to identify the morphology and distribution of serotonergic nerve (5-hydroxytryptamine) in the hippocampus of R. amplexicaudatus, which related to the function of serotonin within the learning and memory process.Materials and Methods:Five R. amplexicaudatus bats were brought from Gunung Kidul cave, Yogyakarta, Java Island, Indonesia. The bats were anesthetized using ketamine and xylazine. R. amplexicaudatus then perfused intracardially. The brain samples were collected processed into paraffin block, and a further cut in 8 µm thickness serially. The tissue slides were stained using hematoxylin-eosin, cresyl echt violet, and immunohistochemistry with rabbit’s anti-serotonin (1:200). The results observed and analyzed quantitatively and qualitatively using image J (https://imagej.nih.gov/ij/) (Bethesda, Maryland, USA) and GraphPad Prism 7 (La Jolla, CA, USA).Results:The hippocampus of R. amplexicaudatus composed of the dentate gyrus (DG), hippocampus proper (cornu ammonis 3 [CA3], and CA1 as the main area for learning memory), and subiculum. On the DG serotonin immunoreactive cells found within the granular layer (132±35.03 cells/mm2), polymorphic stratum (86.33±11.23 cells/mm2), and molecular layer (93±1 cells/mm2). Meanwhile, on CA3 area, the immunoreactive cells for serotonin found in each stratum. The number of immunoreactive cells on each stratum from highest to the lowest are stratum pyramidal 123.33±15.88 cell/mm2, stratum molecular 63±13.11 cell/mm2, stratum lucidum 62.67±8.08 cell/mm2, stratum radiatum 55.33±510.21 cell/mm2, stratum oriens 48±3.46 cell/mm2, and stratum alveus 28.67±2,52 cell/mm2. In addition, in CA1 also hampers the immunoreactive cells in the pyramidal stratum, molecular, lucidum, oriens, radiatum, and alveus layer, respectively, of each 91±27.40 cell/mm2, 60.33±20.65 cell/mm2, 53.67±4.51 cell/mm244.33±10.40 cell/mm2, 41.33±5.51 cell/mm2, and 27±4 cell/mm2.Conclusion:Taking together the distribution of serotonin-immunoreactive cells in the hippocampus of R. amplexicaudatus mostly found on CA3 followed by CA 1 and DG.

Morphological study of the midbrain tectum in ostrich (Struthio camelus) embryo

In this study the morphological features of the optic tectum in ostrich embryo were studied macroscopically and microscopically. After gross anatomical study, fixed specimens of the optic lobes in 30th, 36th and 40th embryonic days were processed for paraffin sections. Sections were stained by Harris haematoxylin and eosin (H&E), Luxol Fast Blue/Cresyl Echt Violet and Malory PTAH dyes. The optic lobes had large volumes even on the 30th embryonic day and increased proportionally to age. The optic lobe consisted of two parts: gray matter (outer) and white matter (inner). The first external layer of the optic lobe e.g. molecular layer consisted of neural fibres, neuroglia and scarce small neurons. The most common appearance of the optic lobes was characterised by small to medium-sized neurons (rounded to pyramid-shaped with large and pale nucleus consistong of obvious nucleoli arranged in three layers whose thickness increased in the deeper one) supported by neuroglia. Larger size neurons and occasionally multipolar neurons were presented in the interior compared with these layers. The lateral mesencephalic nucleus was detectable in the optic lobe base even on 30th embryonic day and was composed of few multipolar neurons supported by neuroglia. The tectal ventricles were lined with simple cuboidal ciliated ependymal cells in the embryonic period. As embryonic age increased, the ratio of tectal ventricle volume to its thickness decreased. Special stainings showed that Nissl bodies and myelin fibres, also glial fibres were available from the 30th embryonic day and that their density, especially myelin fibres density, increased with age.

Efficacy of CD101, a Novel Echinocandin, in Prevention of Pneumocystis Pneumonia (PCP): Thwarting the Biphasic Life Cycle of Pneumocystis

Background:Pneumocystis spp. are the obligate pathogenic fungi that cause PCP in immunocompromised mammalian hosts. The life cycle of Pneumocystis is thought to be biphasic with asexual replication by trophic forms and sexual production leading to formation of asci/cysts. There is evidence to suggest that infection is initiated by cyst inhalation and asci formation may be essential for the Pneumocystis life cycle. We have previously reported (Cushion, et al. 2010; 5:e8524) that currently available echinocandins are not suitable for monotherapy as large numbers of trophic forms remained after 3 weeks of treatment and asci re-appeared and replication resumed after treatment discontinuation. We evaluated the effects of CD101, a novel long-acting echinocandin, on trophic and cyst forms of Pneumocystis murina and its efficacy in preventing infection in a mouse model of PCP.Methods: Mice (C3H/HeN) were immunosuppressed throughout this 6-week study by dexamethasone (4 mg/L) in acidified drinking water. Infection with P. murina was by intranasal inoculation (2 x 106/50 µL). Mice were divided into groups to receive either vehicle (untreated control), trimethoprim/sulfamethoxazole (TMP/SMX 50/250 mg/kg x 3 per week), or CD101 (20, 2, or 0.2 mg/kg once or 3x per week) intraperitoneally at the time mice were inoculated. After 6 weeks, mice were humanely euthanized and lungs were processed for analysis by homogenization. Slides made from the lung homogenates were prepared for quantification of trophic forms by rapid Wright-Giemsa stain and of asci by cresyl echt violet staining. The reduction in P. murina burden (nuclei of trophic forms and asci) in treatment and untreated control groups was evaluated. The nuclei and asci counts for each lung were log transformed and analyzed by ANOVA. Individual groups were compared by Dunn’s test for multiple comparisons (GraphPadPrismv.6).Results: The reduction in nuclei and asci counts for all groups are shown in the Figure. Statistically significant reductions in nuclei levels compared with untreated controls were demonstrated with all CD101-treated groups except for the 0.2 mg/kg once weekly group. CD101 efficacy was comparable to that of TMP/SMX for 3 of the CD101 dose groups; no nuclei were observed by microscopic evaluation following CD101 dosages of 2 or 20 mg/kg 3x per week or 20 mg/kg once weekly. In terms of asci reduction, all CD101 groups demonstrated statistically significant reductions compared with untreated controls. CD101 efficacy was comparable to that of TMP/SMX for 5 of the CD101 dose groups (all but the 0.2 mg/kg once weekly group), with no asci observed by microscopic evaluation.Conclusion: Asci/cysts appear to be critical for replication as well as transmission of Pneumocystis. CD101 inhibited the formation of both trophic forms and asci of P. murina in thismouse model of PCP in immunocompromised mice. These data demonstrate that CD101 is a viable candidate for prophylactic therapy of PCP. [Display omitted] DisclosuresCushion:Univ. of Cincinnati: Employment; Cincinnati VAMC: Research Funding; Cidara Therapeutics, Inc.: Research Funding. Bartizal:Cidara Therapeutics, Inc.: Employment, Other: Stockholder.

Early differential cell death and survival mechanisms initiate and contribute to the development of OPIDN: A study of molecular, cellular, and anatomical parameters

Organophosphorus-ester induced delayed neurotoxicity (OPIDN) is a neurodegenerative disorder characterized by ataxia progressing to paralysis with a concomitant central and peripheral, distal axonapathy. Diisopropylphosphorofluoridate (DFP) produces OPIDN in the chicken that results in mild ataxia in 7–14 days and severe paralysis as the disease progresses with a single dose. White leghorn layer hens were treated with DFP (1.7 mg/kg, sc) after prophylactic treatment with atropine (1 mg/kg, sc) in normal saline and eserine (1 mg/kg, sc) in dimethyl sulfoxide. Control groups were treated with vehicle propylene glycol (0.1 ml/kg, sc), atropine in normal saline and eserine in dimethyl sulfoxide. The hens were euthanized at different time points such as 1, 2, 5, 10 and 20 days, and the tissues from cerebrum, midbrain, cerebellum, brainstem and spinal cord were quickly dissected and frozen for mRNA (northern) studies. Northern blots were probed with BCL2, GADD45, beta actin, and 28S RNA to investigate their expression pattern. Another set of hens was treated for a series of time points and perfused with phosphate buffered saline and fixative for histological studies. Various staining protocols such as Hematoxylin and Eosin (H&E); Sevier-Munger; Cresyl echt Violet for Nissl substance; and Gallocynin stain for Nissl granules were used to assess various patterns of cell death and degenerative changes. Complex cell death mechanisms may be involved in the neuronal and axonal degeneration. These data indicate altered and differential mRNA expressions of BCL2 (anti apoptotic gene) and GADD45 (DNA damage inducible gene) in various tissues. Increased cell death and other degenerative changes noted in the susceptible regions (spinal cord and cerebellum) than the resistant region (cerebrum), may indicate complex molecular pathways via altered BCL2 and GADD45 gene expression, causing the homeostatic imbalance between cell survival and cell death mechanisms. Semi quantitative analysis revealed that the order of severity of damage declines from the spino-cerebellar, ventral, and dorsal tract respectively, suggesting neuroanatomical specificity. Thus, early activation of cell death and cell survival processes may play significant role in the clinical progression and syndromic clinical feature presentation of OPIDN.

In vitro examination of ontogenesis of developing neuronal cells in vagal nuclei in medulla oblongata in newborns.

The development of neuron cells in vagal nerve nuclei in medulla oblongata was studied in vitro in live newborns and stillborns from different cases. Morphological changes were studied in respiratory nuclei of dorsal motor centre (DMNV) and nucleus tractus solitarius (NTS) in medulla oblongata. The material from medulla oblongata was fixated in 10 micro buffered formalin solution. Fixated material was cut in series of 10mu thickness, with starting point from obex in +/- 4 mm thickness. Special histochemical and histoenzymatic methods for central nervous system were used: cresyl echt violet coloring, tolyidin blue, Sevier-Munger modification and Grimelius coloring. In immature newborns (abortions and immature) in dorsal motor nucleus of the vagus (DMNV) population stages S1, S2, S3 are dominant. In neuron population in vagal sensory nuclei (NTS) stages S1, S2 are dominant. In more advanced stages of development of newborns (premature), in DMNV stages S3 and S4 are seen and in NTS stages S2 and S3 are dominant. In mature phase of newborns (maturity) in vagal nucleus DMNV stages S5 and S6 are dominant, while in sensory nucleus NTS stages S4 and S5 are dominant. These data suggest that neuron population in dorsal motor nucleus of the vagus (DMNV) are more advanced in neuronal maturity in comparison with sensory neuron population of vagal sensory nucleus NTS. This occurrence shows that phylogenetic development of motor complex is more advanced than the sensory one, which is expected to take new information's from the extra uterine life after birth (extra uterine vagal phenotype).

The brain of the common vampire bat, Desmodus rotundus murinus (Wagner, 1840): a cytoarchitectural atlas

The vampire bat, Desmodus rotundus, is exceptionally agile and stealthy in nature. Feeding at night on cattle blood, it is a known scourge carrying rabies. It is endowed with a very high neocortical volume among bats, acute olfactory capabilities and an accessory olfactory system. These characteristics have resulted into an impressive number of neuroanatomical investigations except a long due atlas on its brain. This study presents a cytoarchitectural atlas of the brain of the common vampire, Desmodus rotundus murinus, in the frontal plane, serially between the olfactory bulb and the medulla oblongata. Twenty six selected sections are presented, each separated by about 300 to 560 microns. The atlas figures show lugol fast blue-cresyl echt violet stained hemisections with their matching half in a labeled line drawing. About 595 discrete brain structures (some repeating) have been identified. This study is likely to provide the accurate localization of nuclear groups, whole structures, fiber tracts, and interconnections to facilitate future neuroanatomical and neurophysiological investigations on the vampire brain.

Degenerative Myelopathy and Vitamin a Deficiency in a Young Black-Maned Lion (Panthera Leo)

Degenerative myelopathy and vitamin A deficiency were diagnosed in a 1-year-old, female, black-maned lion (Panthera leo). Diffuse white matter degeneration characterized by dilated myelin sheaths, Wallerian degeneration, and reactive astrocytosis was present at all levels of the spinal cord. With luxol fast blue-resyl echt violet stain, bilaterally symmetrical demyelination was observed in the fasciculus cuneatus of the cervical spinal cord and in peripheral white matter of cervical, thoracic, and lumbar segments. Additionally, the ventral gray columns and brain stem nuclei contained rare chromatolytic neurons with abnormal neurofilament accumulation. Leptomeninges of the cervical spinal cord were focally adhered to the dura and thickened by fibrosis and osseous metaplasia. Vitamin A deficiency was diagnosed based on hepatic vitamin A concentration of 1.71 microg/g dry weight. Adequate hepatic vitamin A concentration for yearling to adult domestic animals ranges between 150 and 1000 microg/g dry weight. Lesions were distinct from those previously described in young captive lions with vitamin A deficiency, which had thickened skull bones and cerebellar herniation. The pathogenesis of vitamin A-associated myelopathy in this lion may be similar to that described in adult cattle, which is believed to result from spinal cord compression secondary to elevated pressure of cerebrospinal fluid.

Analysis of Pneumocystis carinii organism burden, viability and antigens in bronchoalveolar lavage fluid in AIDS patients with pneumocystosis

We examined 96 bronchoalveolar lavage fluid (BALF) specimens from AIDS patients with proven Pneumocystis carinii pneumonia (PCP) in order to compare the relationship of organism burden, viability and antigen expression with disease severity at the time of clinical presentation. Tinctorial analysis of BALF specimens with proven PCP using Diff-Quik, cresyl echt violet and erythrosin B stains to evaluate organism burden and viability. P. carinii antigen examination was performed by Western blot analysis. P. carinii cluster ratios were more sensitive than cyst counts as an indicator of organism burden, and correlated well with the alveolar-arterial oxygen gradient as a measure of disease severity. Erythrosin B, the vital stain used to measure P. carinii viability, displayed a wide range of values and provided little useful information. Antigens of 35-45 and 95kD, which were specific for P. carinii, were found by immunoblot analysis in BALF cellular fraction of most patients with pneumocystosis. By contrast, antigens of 52 and 66 kD, which were found in both BALF supernatant and cellular fractions of P. carinii patients and controls, most likely represented albumin and immunoglobulin G heavy chain, respectively, of host origin. The 35-45 kD antigen was found in 88% of the BALF specimens and appeared to represent an important marker of P. carinii infection. The 95 kD antigen was detected in 49% of the specimens. We conclude that analysis of P. carinii characteristics in BALF specimens of patients with pneumocystis may provide additional information. These data will also be helpful in developing more sensitive assays and in targeting specific P. carinii factors for future investigation.

Surveillance for lesions of bovine spongiform encephalopathy in US cattle.

In October 1987, bovine spongiform encephalopathy (BSE) was described in Great Britain as a novel disease of cattle with neurologic lesions comparable to those of scrapie in sheep and other spongiform encephalopathies of animals and humans. Cases in adult cattle occurred with increasing frequency primarily in southern England during the next several months, and there are approximately 600 new cases each week in Great Britain? Epidemiologic studies incriminated the feeding of rations containing ruminant-derived protein, especially to calves. The prolonged incubation period was similar to that observed in scrapie. The presence in the United States of scrapie and other animal spongiform encephalopathies (transmissible mink encephalopathy and chronic wasting disease of mule deer and elk) provided impetus to survey US cattle for lesions of BSE. A cooperative project between the US Department of Agriculture (USDA), Animal Plant Health Inspection Service (APHIS), Science and Technology, National Veterinary Services Laboratories (NVSL), and the Iowa State University, Department of Veterinary Pathology, was initiated in May 1990 with the goal of examining brain specimens from 250 suspect cattle. Beginning in May 1990, formalin-fixed brain specimens or microscope slides from BSE-suspect cattle were requested, and in April 1991, the project was expanded to include referred cases submitted for rabies examination and found not to be rabies. The criteria used to classify cases as BSE suspects are cattle that (1) are ≥2 years old, (2) have documented signs of neurologic disease, and (3) have received protein supplement as a substantial part of the ration. Specimens are shipped to the NVSL, Ames, Iowa, in standard cartons via US Postal Service or commercial transport systems. Fixed brain specimens are referred to the Iowa State University, Department of Veterinary Pathology, for further processing. Blocks of tissue from 12 areas, if available, are selected as follows: frontal cortex, corpus striatum, temporal cortex, optic chiasm, occipital cortex with hippocampus, thalamus, mesencephalon, pons, cerebellum, rostra1 medulla, obex, and caudal medulla. Tissue blocks are processed by routine methods, embedded in paraffin, sectioned at 8 μm, mounted on glass microscope slides, and stained with hematoxylin and eosin. Special stains, such as Brown-Hopps Gram stain, luxol fast blue-cresyl echt violet, and glial fibrillary acidic protein, are used as needed. Evaluation of the morphology is based on light microscopy.

Autonomic and histopathological effects of percutaneous trigeminal ganglion compression in the rabbit

The histopathological and autonomic effects of percutaneous trigeminal ganglion compression for trigeminal neuralgia were studied in New Zealand White rabbits. Drops in mean arterial blood pressure of 38% and in heart rate of 30% were observed during compression (p less than 0.0001). Corneal reflex, pinprick sensation, and mastication strength were intact in 13 of 14 rabbits after compression. These findings resembled the effects of percutaneous compression in humans and suggested that the New Zealand White rabbit is a useful model for the study of percutaneous compression. Trigeminal sensory roots and ganglia from 14 rabbits killed at intervals from 1 to 84 days after percutaneous compression were sectioned and stained using immunoperoxidase for neurofilaments, hematoxylin and eosin, luxol fast blue, and cresyl echt violet. Focal axonal damage and demyelination were present 7 days after compression. No difference could be detected in the perikaryonal distribution of neurofilaments between compressed and control trigeminal ganglia. Focal demyelination and Schwann cell proliferation preceding remyelination were present in the trigeminal sensory root at 84 days. Differential injury of axons compared to trigeminal ganglion cell bodies suggests that axonal regeneration is possible and may contribute to the recovery of motor and sensory function in patients after percutaneous compression.

Spontaneous Lesions in Subchronic Neurotoxicity Testing of Rats

Male and female Fischer 344 rats, 30 weeks of age, were examined for neuropathologic changes after a 13-week inhalation neurotoxicologic study. Tissues were preserved by whole-body perfusion with 1.5% glutaraldehyde/4% formaldehyde solution. An extensive set of neural tissues was embedded in paraffin, sectioned, and stained with hematoxylin and eosin, luxol fast blue/periodic acid-Schiff/hematoxylin, Sevier-Munger silver, and cresyl echt violet. Lesions in the central and peripheral nervous system were comparable between sexes and between control and treated animals. Bilateral swollen axons were present in the medial aspect of the nucleus gracilis adjacent to the area postrema. Occasional swollen axons also were observed in the dorsal and ventral funiculi of the spinal cord. Degeneration of individual nerve fibers was present in the trapezoid body, vestibular nerve root, trigeminal nerve, cerebellar peduncles, and the funiculi of the spinal cord. Individual nerve fiber degeneration also was present in the spinal nerve roots, sciatic and tibial nerves. Nerve fiber degeneration was characterized by myelin disruption and degeneration, vacuoles and axonal fragmentation. Similar spontaneous neuropathology may be encountered in rats from other subchronic neurotoxicologic studies and must be differentiated from treatment-related toxicity.

Use of Cresyl Echt Violet for the Staining of Pneumocystis carinii as Compared to Grocott's (GMS) and Giemsa Methods

Use of Cresyl Echt Violet for the Staining of <I>Pneumocystis carinii</I> as Compared to Grocott's (GMS) and Giemsa Methods

Use of Cresyl Echt Violet for the Staining ofPneumocystis cariniias Compared to Grocott's (GMS) and Giemsa Methods

Pneumocystis carinii (P. carinii), a microorganism often associated with AIDS patients, stains a brilliant rose-purple with cresyl echt violet. The original procedure used solutions that were unstable, giving irreproducible results. This modification produces a short reliable method. It is the preferred method used in our laboratory over Grocott's methenamine silver (GMS) and Giemsa to differentiate P. carinii from fungal spores. (The J Histotechnol 12:39, 1989).

The Neocortex of the Dog

SummaryThis article presents abundant rigorous information concerning the whole of the neocortex of a gyrencephalate mammal (the dog), including the buried cortex. The outline of 50 μm transverse sections stained with cresyl echt violet were measured with a Vids II image analyser, measurements being taken between reference points which mostly consisted in the edges and bottoms of the sulci. These measurements were used to construct stripwise representations of the cortex of the sections, which were then joined to produce a flat map of the neocortex showing the locations of 21 structural types. The total extent of each type was calculated, together with proportion of the cortex which is hidden from view in classical cytoarchitectonic maps.

Cell death in Clarke's column after spinal cord transection.

The death of embryonic central nervous system (CNS) neurons deprived of a target is well established. In adult rats, similar cell death of corticospinal and rubrospinal motor neurons occurs as a delayed response to spinal cord transection. We document the loss of neurons in Clarke's column, secondary ascending spinocerebellar neurons in adult rats, after complete spinal cord transection at T-9. Twenty-five weeks after spinal cord transection, horseradish peroxidase (HRP) studies showed a dramatic loss of labeled cells in rats with transected spinal cords as compared to matched control rats. Cresyl echt violet-stained sections failed to support the hypothesis that unlabeled cells persist in a shrunken, inactive state; instead we found far fewer identifiable neurons in Clarke's column. Although we saw little gliosis in the area of cell loss, gliosis was evident in the adjacent corticospinal tract which was severed in the original surgical injury. Amputation of the right hind limb resulted in a paradoxical increase in labeled Clarke's column cells on the right. Total cells stained with cresyl echt violet in amputated animals were not different from right to left. The increase in labeled cells on the amputated side may have been caused by an increase in metabolic activity of these deafferentated neurons which resulted in more effective axoplasmic transport of the HRP label.

Studies on the epithalamus. I. Morphology of post‐mortem degeneration: The habenular nucleus in dog

AbstractThis study was undertaken to observe the structural changes occurring in myelin, axis cylinders, Nissl substance, nucleus, and general cell architecture at specific post‐mortem time intervals.The habenulopedunclar tract and the habenular nucleus of 36 adult dogs were sectioned (6 μ to 14 μ) and stained with luxol fast blue‐cresyl echt violet, 2% osmium tetroxide, and a two hour Protargol method. At O hour post‐mortem the cell membrane is relatively distinct, nuclear membrane delicate but distinct, nucleolus clear, Nissl bodies are observed in larger cells of the habenular nuclei.From 6–24 hours three main areas of change are noted: an agglutination, fragmentation, and obliteration of the Nissl substance; a progressive increase in the irregularity of the nuclear and cell membrane; a progressive increase in vaculation and in the perinuclear halo. From 24–36 hours the cytoplasm appears extremely granular with the granulation extending into the nucleus. Some cells appear swollen with indistinct nuclei or appear anucleated. From 36–48 hours the cytoplasm shows increased granulation and at 48 hours few cells show nuclei. Most cells show uniform color in the cytoplasm and nuclear area. Any remaining nuclei in the 36–48 hour interval appear pyknotic and finely granular. The myelin sheaths and axis cylinders show only limited structural change over the time span of this study.