Utilizing Light Microscopy Research Articles

Anatomical and Histochemical Analysis of Hoya pentaphlebia MERR. Flower: Insights into Structure and Chemical Composition

Hoya R.Br. is an epiphytic plant known as an exotic ornamental plant with distinctive, unique, and fragrant flowers. Investigating its floral structure is crucial for understanding how these structures may contribute to the production and storage of secondary metabolites emitted by Hoya. This study aimed to identify the type and position of floral glands in Hoya pentaphlebia. The investigations began by identifying the type and position of the floral glands, utilizing light microscopy, electron microscopy, and histochemical staining techniques. Secondary nectaries (sn) were discovered in the corona lobe, while conical-shaped glandular trichomes (unicellular) (ct) were at the adaxial epidermis of the corolla. The secretory activity of proteins, lipids, polysaccharides, and starch grains was found in sn, whereas ct detected only lipids and proteins. Subsequent studies to identify the secondary metabolite profiles characterizing aroma emitted from H. pentaphlebia flowers using gas chromatography-mass spectrometry (GC-MS) showed 26 compounds were identified, with the methyl salicylate (MeSA) compounds being the most abundant. In conclusion, this study successfully identified the floral glands and secondary metabolites present as aromas in the species studied. Sn and ct were discovered to be present for the first time in H. pentaphlebia, providing new information into the Hoya’s floral structures. The presence of floral glands indicates the existence of secondary aromatic metabolites that play a role in the interaction between plants and numerous environmental elements.

Examination of wnt signaling mediated melanin transport and shell color formation in Pacific oyster (Crassostrea gigas)

Mollusca exhibit remarkable diversity in shell coloration, attributed to the presence of melanin, a widely distributed pigment with various essential roles, such as mechanical strengthening, antioxidation and thermoregulation. However, the regulatory network governing melanogenesis and melanin transport in molluscs remains poorly understood. In this study, we conducted a systematic analysis of melanin distribution and transport in the Pacific oyster, utilizing light microscopy and high-resolution transmission electron microscopy. In addition, we characterized CgWnt1 and CgWnt2b-a in Crassostrea gigas, and analyzed Wnt signaling in melanocyte formation. Expression analysis revealed that these genes were predominantly expressed in the mantle of black-shelled individuals, particularly in the outer fold of the mantle. Furthermore, we employed RNA interference and inhibitors to specifically inhibit Wnt signaling in both in vivo and in vitro. The results revealed impaired melanogenesis and diminished tyrosinase activity upon Wnt signaling inhibition. These findings suggest the crucial role of Wnt ligands and downstream factors in melanogenesis. In summary, our study provides valuable insights into the regulatory mechanism of shell pigmentation in C. gigas. By demonstrating the promotion of melanogenesis through Wnt signaling modulation, we contribute to a better understanding of the complex processes underlying molluscan melanin production and shell coloration.

The first record of the giant pill-millipede genus Prionobelum Verhoeff, 1924 from Thailand, with the integrative description of two species (Diplopoda, Sphaerotheriida, Zephroniidae).

Thailand hosts a very rich but underexplored giant pill-millipede (Sphaerotheriida) fauna, with 11 of its 13 species described in the last three years. Currently, all known Thai giant pill-millipedes belong to the genera Zephronia Gray, 1832 (nine species) and Sphaerobelum Verhoeff, 1924 (four species). Here we describe the first two species of the genus Prionobelum Verhoeff, 1924 (previously restricted to Vietnam and China), Prionobelum inthanonense n. sp. and P. naevium n. sp. from Thailand. The species occur at Thailands highest mountain (2500 m) Doi Inthanon and the lowland rainforests at Bang Lang National Park touching the border with Malaysia. Both species are described integratively, utilizing light microscopy, scanning electron microscopy as well as DNA barcoding. Both new species of Prionobelum differ from other Zephroniidae species, as well as from one another, by more than 20% p-distance in the COI barcoding gene suggesting that potential closer related species are still awaiting discovery.

Taxonomic relevance of stem and leaf anatomy in 10 endemic Fritillaria species from the Mediterranean Region

Fritillaria has important medicinal and horticultural values. This research aims to comprehensively assess the taxonomic relevance of micro-anatomical features within ten species belonging to Fritillaria subgenus Fritillaria, namely F. aurea, F. bithynica, F. crassifolia, F. enginiana, F. glaucoviridis, F. kittaniae, F. serpenticola, F. sibthorpiana, F. wendelboi, and F. whittallii, utilizing light microscopy. The majority of these species exhibit endemism within the Turkish Mediterranean Region, with F. aurea and F. crassifolia representing endemic Irano-Turanian elements, while the rest are native to the Eastern Mediterranean Region. In this anatomical investigation, we described and compare the cross-sections of the stem and leaves. Results revealed substantial variation in anatomical traits among the studied species. The presence or absence of eglandular trichomes, crystal granules in the leaf surface and cross section and in stem pith region, and the arrangement of parenchymal and sclerenchymal layers in the stem offered useful taxonomic markers. Similarly, leaf characteristics such as epidermal cell sizes, stomatal indices, mesophyll types, and guard cell shapes provided distinguishing features. A dichotomous key was developed based on these anatomical traits to aid in the accurate identification of Fritillaria species, highlighting the practical utility of these features in taxonomic studies. The findings underscore the importance of micro-anatomical traits as valuable tools for distinguishing and classifying plant species, especially in cases where morphological traits alone may not provide sufficient differentiation.

Morphological characteristics of pollen and cypsela in the genus Rhaponticum (Asteraceae) from Turkey and their systematic significance

Pollen and cypsela morphology of four species of the genus Rhaponticum (Asteraceae) distributed in Turkey were investigated and compared utilizing light microscopy and scanning electron microscopy to identify these characteristics and to evaluate the diagnostic value of them for contribution to the systematics of the Turkish Rhaponticum. The pollen grains of Rhaponticum are radially symmetrical and isopolar. Their shape is prolate-spheroidal and oblate-spheroidal, with the polar axis ranging from 32 to 56.64 μm and the equatorial axis ranging from 31.92 to 56.64 μm. The aperture type is usually trizonocolporate, and rarely tetracolporate. Exine sculpturing can be divided into two types, namely microechinate and echinate. The cypselas are obovoid or narrowly obovoid in shape and dark brown with cream at the base, brown or dark yellow-green in color. The size of the cypselas range between 3.19–11 mm in length and 1.4–4.5 mm in width. The pappus shows variation in type and status: barbellate, scabrose and barbellate at apex, plumose or only scabrose and persistent or deciduous. Cluster analysis and principal component analysis revealed that especially pollen size, pollen shape, exine ornamentation, cypsela length and pappus type are significant variables for separating species in the taxonomy of the genus.

Identification of a Novel Amino Acid Motif Responsible for Peptide Aggregation in vitro.

Peptides and their derivatives comprise a substantial sector of drug development initiatives due to their specific biological activities and broad chemical versatility. Among the challenges of peptide drug development is a reduction in peptide solubility that leads to peptide aggregation. This dramatically reduces a peptide’s biological availability and prevents its further testing in vivo.Here we report a physicochemical analysis of peptides that inhibit the CMG helicase, the main replicative helicase within the cell. We demonstrate that the inhibitory peptides had a pronounced propensity to form aggregates in vitro by utilizing light microscopy and a fluorescence‐based peptide aggregation assay. By applying a peptide chase approach and abovementioned testing assays, we identified a short amino acid motif of X‐Leu‐Met‐Leu‐X that was responsible for peptide aggregation. Amino acid substitutions at these key residues were studied to confirm their contribution towards aggregation. Interestingly, substitution of either Leucine residues with Serine residues dramatically increased peptide solubility.

Light microscopy and scanning electron microscopy: A helping tool to identify the adultrant of dye from Curcuma longa L rhizome, and its ecofriendly applications on pharmaceutical products.

The current study was embraced to examine the morphoanatomical distinguishing proof utilizing light microscopy (LM), scanning electron microscopy (SEM) and antibacterial activities of turmeric extract utilizing amoxicillin and ciprofloxacin. Cross over part of the rhizome is roundabout in structure. The peripheral layer is the periderm which comprises of 6-7 layers of digressively lengthened cells. This is trailed by an expansive cortex made of flimsy walled parenchyma cells with intercellular spaces. The antibacterial activities of turmeric extract in blend with drug items like amoxicillin and ciprofloxacin was likewise examined at various fixations. Different turmeric samples and drug items were gathered from various shops of Lahore. The samples were analyzed for antibacterial activities by utilizing pour plate method. In general outcomes showed fundamentally higher zone of inhibition of turmeric extract in combination with ciprofloxacin and lower zone of inhibition of turmeric extract in combination with amoxicillin. It is inferred that turmeric extract have hostile impact in blend with amoxicillin. Thus, the combination of turmeric extract with antimicrobial (amoxicillin) diminished the intensity of antibiotic. The turmeric extract have more antibacterial activity in mix with ciprofloxacin. Thus, the blend of turmeric extract with antibiotic (ciprofloxacin) expanded the intensity of antibiotic. RESEARCH HIGHLIGHTS: Morphoanatomical study of Turmeric rhizome using light microscopy (LM) and scanning electron microscopy (SEM). The antibacterial activities of turmeric extract like amoxicillin and ciprofloxacin was also investigated at different concentrations.

Accessing pore microstructure–property relationships for additively manufactured materials

AbstractUnderstanding structure–property (SP) relationships is essential for accelerating materials innovation. Still being in the state of ongoing research and development, this is especially true for additive manufacturing (AM) in which process‐induced imperfections like pores and microstructural variations significantly influence the material's properties. That is why, the present work aims at proposing an approach for accessing pore SP relationships for AM materials. For this purpose, crystal plasticity (CP) simulations on reconstructed domains based on experimental measurements are employed to allow for a microstructure‐sensitive investigation. For the considered Ti–6Al–4V specimen manufactured by laser powder bed fusion, the microstructure and pore characteristics are obtained by utilizing light microscopy and X‐ray computed tomography at the microscale. Employing suitable statistical analysis and reconstruction, statistical volume elements with reconstructed pore distributions are created. Using them, microscale CP simulations are performed to obtain fatigue indicating parameters. Employing a further statistical analysis, fatigue ranking parameters are derived for a comparison of different microstructures. Additionally, a comparison with the empirical Murakami's square root area concept is made. Results from first numerical studies underline the potential of the approach for understanding and improving AM materials.

Electrochemical Therapy of In Vivo Rabbit Cutaneous Tissue.

To examine the acid-base and histological changes in in vivo rabbit cutaneous tissue after electrochemical therapy. In vivo rabbit tissue study. The shaved skin on the backs of female Oryctolagus cuniculi were assigned to treatments with or without tumescence with normal saline. Two platinum-needle electrodes were inserted into each treatment area and connected to a direct current (DC) power supply. Voltage (3-5 V) was varied and applied for 5 minutes. The wound-healing process was monitored via digital photography and ultrasonography until euthanasia at day 29. Treatment areas were biopsied, and specimens were sectioned through a sagittal midline across both electrode insertion sites. Samples were then evaluated utilizing light microscopy (hematoxylin and eosin, Masson's Trichrome, and Picrosirius red). Treatment sites developed mild inflammation that dissipated at lower voltages or became scabs at higher voltages. Ultrasonography demonstrated acoustic shadowing with spatial spread that increased with increasing voltage application. The 4- and 5-V sites treated with saline had localized areas of increased tissue density at day 29. Although specimens treated with 3 V did not look significantly different from control tissue, 4- and 5-V samples with and without saline tumescence had finer, less-organized collagen fibers and increased presence of fibrocytes and inflammatory infiltrates. Electrochemical therapy caused localized injury to in vivo rabbit cutaneous tissue, prompting regenerative wound repair. With future development, this technology may offer precise, low-cost rejuvenation to restore the functionality and appearance of dermal scars and keloids. NA Laryngoscope, 131:E2196-E2203, 2021.

Implication, visualization, and characterization through scanning electron microscopy as a tool to identify nonedible oil seeds.

Second-generation biofuels prove to be a distinctive and renewable source of sustainable energy and cleaner environment. The current study focuses on the exploration and identification of four nonedible sources, that is, Brassica oleracea L., Carthamus oxyacantha M.Bieb., Carthamus tinctorius L., and Beaumontia grandiflora Wall., utilizing light microscopy (LM) and scanning electron microscopy (SEM) for studying the detailed micromorphological features of these seeds. LM revealed that size ranges from 3 to 20 mm. furthermore, a great variety of color is observed from pitch black to greenish gray and yellowish white to off white. Seeds ultrastructure study with the help of SEM revealed a great variety in shape, size, color, sculpturing and periclinal wall shape, and so on. Followed by the production of fatty acid methyl esters from a novel source, that is, seeds oil of Brassica oleracea L. (seed oil content 42.20%, FFA content 0.329 mg KOH/g) using triple metal impregnated montmorillonite clay catalyst (Cu-Mg-Zn-Mmt). Catalyst was characterized using SEM-EDX, FT-IR. Maximum yield of Brassica oleracea L. biodiesel (87%) was obtained at the conditions; 1:9 of oil to methanol ratio, 0.5 g of catalyst, 5 hr reaction time, and 90°C of temperature. Synthesized biodiesel was characterized by FT-IR, GC-MS, and NMR. Fuel properties of the Brassica oleracea L. FAMES were determined and found in accordance with ASTM standards.

Characterization of the Pore Structure in Ice from Water Added at Different Temperatures

The present study describes ice characterization technique by utilizing light microscopy. Two different optical setups were used and compared. For ice structure characterization, ice was formed by adding water to an ice base layer: pouring hot water (+20 °C), pouring cold water (+3 °C) and spraying of hot water (+20 °C) water. Ice substrate specimens were made (20 x 30 x 20 mm prepared in a polypropylene mould) at -20 °C for 48 h. The heat flow direction governed the orientation of the air bubbles, and set the inner structure of ice. Pouring hot water onto ice slowly solidified the top layer and created channel-like pores perpendicular to the top surface, but cold water quickly solidified the top layer and created chaotically oriented air bubbles.

Formation of Thermally Sprayed Coatings on Grid-Like Structure Substrate

The main goal of this contribution is to investigate the influence of the substrate morphology on the resulting thermally sprayed coatings microstructure. Therefore, three different representative coating systems and/or thermal spray techniques were utilized to produce the coatings on grid-like structure substrates: (i) CoNiCrAlY bond coat (BC) sprayed by high velocity oxygen fuel (HVOF) technique and yttria stabilized zirconia (YSZ) top coat (TC) sprayed by means of atmospheric plasma spray (APS) technique, (ii) YSZ coating sprayed by means of APS and (iii) YSZ coating sprayed by means of nanoparticle colloid suspension plasma spraying (SPS). The shadowing effect of thermal spray coatings in relation with the grid-like substrate structure was investigated in detail. Resulting microstructure of sprayed samples was studied utilizing light microscopy, digital image analysis, scanning electron microscopy, energy-dispersive spectrometer and X-ray diffraction techniques.

Apoptosis and Necrosis of Human Breast Cancer Cells by an Aqueous Extract of Euphorbia hirta leaves

: Introduction: Traditional medicines for mammary tumour are unreasonable and have genuine symptoms. Non-ordinary normal medications have increased wide acknowledgment because of their assurance of a cure with negligible or no symptoms, however minimal experimental confirmation exists. One such basic cure is the leaves of the Euphorbia hirta plant. Methods: It is initially reported utilization of the fluid concentrate of Euphorbia hirta leaves breast cancer cells. The capacity of the concentrate to impel apoptosis and corruption in the human bosom malignancy cell line MCF-7, contrasted with typical human skin fibroblasts (MDA MB-231), was dictated by morphological changes in the cells utilizing light microscopy, DNA fragmentation, and brilliant stains (Annexin V and Propidium Iodide) utilizing Flow Cytometry and fluorescent microscopy. Results: Apoptosis was instigated in both cells, and more in MCF-7, when they were treated with 25% and half concentrate, while rot was watched mostly after presentation to raised concentrate fixations (75%). DNA discontinuity came about for both cells, in a period and dosage subordinate way. Both cells, at all concentrate fixations, demonstrated no critical contrasts in the quantity of living, dead, apoptotic, and necrotic cells. Conclusion: At long last, the outcomes might show that apoptotic changes in MCF-7 might be free of caspase-3, which is included in apoptosis and is inadequate in MCF-7 cells.Key words: Apoptosis, Aqueous extract, Euphorbia hirta leaves, Human breast cancer cells, Necrosis.This article has been retracted from Journal of Young Pharmacists on 16th December 2019. Retraction notice will be published in Jan-Mar, 2020 issue.

Relationship between Mast Cell Counts and Different Types of Periodontitis

Background and aims. Mast cells play an important role in allergic reactions, host defense, local homeostasis, inflammation and angiogenesis. The aim of this study was to evaluate the relationship between mast cell counts and different types of periodontitis. Materials and methods. Gingival specimens were taken from 20 moderate-to-advanced chronic and 19 moderate-toadvanced aggressive periodontal sites as case groups and 18 healthy/gingivitis sites as control group in routine periodontal flap and crown lengthening procedures. All the specimens were stained by toluidine blue for mast cell counting and hematoxylin/eosin to assess inflammation. Inflammatory and mast cells were assessed in 5-micron sections by two observers 3 times, utilizing light microscopy at ×100 and ×400 magnification. ANOVA and t-test were used to analyze data. Statistical significance was defined at α=0.05. Results. Mast cell counts were higher in chronic versus aggressive periodontitis and healthy/gingivitis cases (P = 0.000). The aggressive periodontitis cases did not demonstrate higher counts of mast cells as compared to healthy/gingivitis cases (P >0.05). There was no relationship between mast cell counts and degree of inflammation in the three groups. Conclusion. The present study indicated higher mast cell counts in the chronic periodontitis sites compared to other sites. The results of this study suggest that further studies are necessary to simultaneously evaluate dynamic aspects of host defense and other aspects of immune system.

Microvasculature of the buffalo (Bubalus bubalis) choroid plexuses: Structural, histochemical, and immunocytochemical study

The choroid plexuses (CPs) in mammals produce the cerebrospinal fluid (CSF). In the literature, the morphology of CPs and the process that regulates the production of CSF are virtually nonexistent for domestic ruminants. Thus this study has two aims: 1. to investigate the morpho-structure of the buffalo CP microvasculature utilizing light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques, and 2. to investigate the relationship between the blood vessels and both the elongated cells and the cells with multiple protrusions located in the CPs. SEM and TEM analyses of the CPs from buffalo brain showed morphological and structural features similar those reported in other mammalian species. Moreover the blood microvasculature is the major component responsible for the formation of the CSF, secreted by the encephalic CPs. In addition the chemical composition of this fluid depends on several morpho-functional characteristics of the vascularization of the CPs. These characteristics are as follows: two shapes of the vascular organization: lamina-like and ovoid-like elongated cells of the CPs, which connect the ventricular cavities to the blood capillaries; and the CP capillaries have diverse forms. In the present study the employment of NADPHd and NOS I was taken as indirect evidence for the presence of NO for investigation their specific role in CPs. Then NOS I immunoreactivity is found in the walls of CP blood vessels demonstrating indirectly the presence of NO with a vaso-dilatatory and autoregulation function of vascular tone by cholinergic nerve stimulation of blood vessel smooth muscle.

Hematology, Serum Chemistry, and Cytology Findings from Apparently Healthy Atlantic Bottlenose Dolphins (<I>Tursiops truncatus</I>) Inhabiting the Estuarine Waters of Charleston, South Carolina

This study reports comprehensive baseline data for hematology, serum chemistry, and cytology variables in 63 apparently healthy Atlantic bottlenose dolphins (Tursiops truncatus) inhabiting the estuarine waters of Charleston (CHS), South Carolina (SC). Blood and cytology samples were collected from bottlenose dolphins in August 2003 and August 2004 during capture-release health assessment studies. Means, medians, standard deviations, 95% CI, and ranges were calculated for the population’s hematology, serum biochemistry, and serum protein electrophoresis parameters. All of the parameters for which a published range was available were close to or within the ranges previously reported. Comparisons by age, gender, and pregnancy status revealed statistically significant differences (p ences (p ences ( < 0.05) for several hematology and serum chemistry parameters. Blowhole, rectal, and gastric swabs were examined for cytologic abnormalities, utilizing light microscopy. There were no pathologic findings in the samples; however, 4% (2/51) of the dolphins sampled had mild or moderate blowhole inflammation. The prevalence of gastric inflammation was 26% (13/50), and severe gastric inflammation was present in three of the dolphins sampled (6%). The majority of animals with gastric inflammation were male (10/13, 77%). In fact, all cases of severe inflammation occurred in males, and none were present in 2004. These data provide a baseline from which to compare hematological, serum chemistry, and cytological parameters in wild dolphin populations.

A Survey of Environmental Contamination with Ascarid Ova, Wallingford, Connecticut

Few studies have been conducted in the United States to quantify the potential risk associated with encountering zoonotic ascarid ova in the environment. In an effort to raise awareness and to better understand the risk of acquiring visceral larva migrans in south central Connecticut, this environmental survey was conducted to determine the prevalence of ascarid ova (Toxocara canis, Toxocara cati, Baylisascaris columnaris, and Baylisascaris procyonis) in public areas of Wallingford, Connecticut, to compare prevalence levels among these public areas, and to determine what host species are primarily responsible for environmental contamination. A preliminary study was conducted to determine if ascarid ova of different species could be identified by size and appearance utilizing light microscopy alone; results did not support the differentiation of species via these methods. To determine the prevalence of environmental contamination with ascarid ova, samples of approximately 250 g of soil were collected from park green areas, playgrounds, public housing areas, parkways, and a school. Ova were detected in 46 (14.4%) of 319 samples collected. Ova were collected from three of the 60 (5.0%) park green area samples, 11 of the 40 (27.5%) playground samples, six of the 98 (6.1%) public housing samples, and 26 of the 96 (27.1%) parkway samples. Public areas of Wallingford, Connecticut are frequently contaminated by potentially infectious ascarid ova. Of particular concern is the high degree of contamination of playgrounds and the potential risk these areas pose to children's health.

Redistribution of thorotrast into a liver allograft several years following transplantation: a case report

Thorotrast was used as a radiographic contrast agent in the United States from about 1930 to the mid-1950 s. Its use was discontinued when it was recognized that its radioactivity caused long-term deleterious effects. Such long-term sequelae of intravascular Thorotrast injection include, most notably, hepatic and hematologic malignancies and hepatic fibrosis. Some patients who had received Thorotrast subsequently received liver transplants. However, it was not known whether or not Thorotrast could become redistributed within the new allograft. A single report in 1994 demonstrated that radioactivity was detected by γ-ray spectroscopy in liver allografts shortly after transplantation. No report has identified Thorotrast in the allografts of long-term transplant survivors, and the redistribution of Thorotrast into allografts has not been documented histologically or by electron microscopy. We report a case of recurrent Thorotrast into a liver allograft 10 years post-transplant. We evaluated the native liver and allograft specimens for the presence of thorium utilizing light microscopy, electron microscopy and electron X-ray microanalysis. This case report demonstrates for the first time the redistribution of Thorotrast into a long-surviving liver allograft using histologic, electron microscopic and X-ray microanalysis techniques.

Redistribution of thorotrast into a liver allograft several years following transplantation: a case report

Thorotrast was used as a radiographic contrast agent in the United States from about 1930 to the mid-1950 s. Its use was discontinued when it was recognized that its radioactivity caused long-term deleterious effects. Such long-term sequelae of intravascular Thorotrast injection include, most notably, hepatic and hematologic malignancies and hepatic fibrosis. Some patients who had received Thorotrast subsequently received liver transplants. However, it was not known whether or not Thorotrast could become redistributed within the new allograft. A single report in 1994 demonstrated that radioactivity was detected by γ-ray spectroscopy in liver allografts shortly after transplantation. No report has identified Thorotrast in the allografts of long-term transplant survivors, and the redistribution of Thorotrast into allografts has not been documented histologically or by electron microscopy. We report a case of recurrent Thorotrast into a liver allograft 10 years post-transplant. We evaluated the native liver and allograft specimens for the presence of thorium utilizing light microscopy, electron microscopy and electron X-ray microanalysis. This case report demonstrates for the first time the redistribution of Thorotrast into a long-surviving liver allograft using histologic, electron microscopic and X-ray microanalysis techniques.

NGFR-mRNA expression in sciatic nerve: a sensitive indicator of early stages of axonopathy

Expression of the low-affinity nerve growth factor receptor (NGFR) in the sciatic nerve (particularly Schwann cells) is high during development but is downregulated upon establishment of the mature axon-Schwann cell relationship. NGFR is re-expressed by Schwann cells if this relationship is altered by degeneration of axons (axotomy) or myelin (tellurium intoxication). To determine the sensitivity of NGFR expression to axonal injury, we have assayed NGFR-mRNA levels in proximal and distal regions of nerves exposed to the axonopathic agents acrylamide and isoniazid, as well as in proximal and distal stumps of axotomized nerves. NGFR-mRNA was elevated in all three models and correlated regionally with sites of axonal perturbation. In distal regions of acrylamide- and isoniazid-intoxicated nerves, NGFR-mRNA was elevated at least 2 days prior to visible signs of axonal degeneration as assayed by morphological techniques utilizing light microscopy. NGFR-mRNA was also elevated in proximal regions of axotomized and acrylamide-intoxicated nerves prior to signs of axonal degeneration. In these models, increased mRNA expression correlated with alterations in the size distribution of axonal cross sections. The common response in all of these situations indicates that NGFR expression, in addition to being a marker for axonal degeneration, is also a sensitive indicator of less profound perturbations in normal axon-Schwann cell interactions, including early stages of axonopathy. We suggest that assay for NGFR-mRNA may be utilized as a rapid and simple method (relative to more labor-intensive morphological methods) to screen for peripheral neurotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)