Re-innervation of rat molar tooth pulp following transection of the inferior alveolar nerve

The inferior alveolar nerves (IAN) of young male Wistar rats (b.wt. greater than or equal to 200 g) were transected unilaterally, slightly proximal to the mandibular foramen under anesthesia with chloral hydrate (0.4 g/kg, i.p.). After various postoperative periods of time, the animals received horseradish peroxidase (HRP) applications to 3 mandibular molar tooth pulps on both sides and were fixed by transvascular perfusion 24 h later. Horizontal 60 microns sections of the trigeminal ganglion were incubated with tetramethylbenzidine hydrochloride and the cross-sectional areas of all the labeled neuronal cell bodies were measured. The average number of labeled cells on the untransected (control) side was 148 (n = 26), with cross-sectional areas ranging between 131.9 and 2129.6 microns 2. Of these, 42.5% fell between 300 and 600 microns 2. About 13.5% (n = 7) of the primary neurons innervating the tooth pulps escaped the ipsilateral neurotomy and were labeled by HRP application on postoperative day 0. With HRP application on postoperative day 3, the number of labeled neurons recovered to 56.8% (n = 7) that of the control and maintained this level up to postoperative day 75. From postoperative days 3 through 75, the cell size spectrum of labeled neurons on the transection side was similar to that of the control and no consistent tendency of alteration was observed; i.e. they were distributed between 134.4 and 2214.3 microns 2, with the mode being 41.5% in the range between 300 and 600 microns 2 (n = 19).

Effect of direct-current stimulation on the growth plate. In vivo study with rabbits

Electrical stimulation of 8 microA direct current was applied to the femoral distal growth plate of young rabbits for periods of 1, 2, and 3 weeks to examine the effect on bone growth. The results were analyzed using X-ray measurement, histological observation including tetracycline labeling, and glycosaminoglycans analysis. No obvious differences between the stimulated side and the control side were observed in the morphological and biochemical studies, but characteristic thickening of the growth plate caused by the accumulation of hypertrophic cells was found in the group stimulated for 2 weeks. Electricity affects the cell behavior of the growth plate, but it is necessary to find more appropriate conditions to stimulate obvious bone growth.

The distribution of vasoactive intestinal polypeptides and calcitonin gene-related peptide in the periodontal ligament of mouse molar teeth

The distribution of VIP- and CGRP-containing nerve fibres was examined by indirect immunofluorescence. There were many such fibres in the lower third of the ligament, some around the blood vessel close to the socket wall. In the middle third of the ligament, some CGRP-containing fibers entered from the lateral wall of the socket; this type of fibre was more numerous in the lower third than in middle third. There were some VIP-containing fibres but no CGRP-containing fibres in the ligament surrounding the furcation of the molar roots.

Leucine-enkephalin-, neurokinin A- and cholecystokinin-like immunoreactivities in the guinea pig tongue

The occurrence of these neuropeptides was examined by immunofluorescence. Leu-Enk-like immunoreactivity was seen in nerve fibres associated with the epithelium, blood vessels and lingual salivary glands as well as in ganglionic cells within the tongue. Neuropeptide A-like immunoreactivity was found in nerve fibres associated with the epithelium, taste buds, blood vessels and lingual salivary glands. Cholecystokinin-like immunoreactivity was found in some nerve fibres around blood vessels as well as in ganglionic cells. The coexistence of these neuropeptides and substance P was also demonstrated in some nerve fibres and ganglionic cells within the tongue. Like substance P, these neuropeptides could be involved in blood flow regulation, salivation and as trophic factors for taste buds.

Fine structure of calcitonin gene-related peptide-immunoreactive nerve fibres in the rat temporomandibular joint

The distribution and fine structure of these nerve fibres was examined by immunoelectron microscopy. CGRP-immunoreactive fibres were seen in the nerve bundles, blood vessels and periosteum around the condyle as well as in the disc. These nerve fibres were unmyelinated and had diameters varying from 200 to 600 nm. They were completely or partially enclosed by Schwann cell cytoplasm and did not form synaptic contact with any cells. CGRP-immunoreactive nerve fibres may be sensory nature and this peptide could be involved in pain transmission and neurogenic inflammation.

Carbonic anhydrase activity in the trigeminal primary afferent neuronal cell bodies with peripheral axons innervating the mandibular molar tooth pulps of the rat

Trigeminal primary afferent neuronal cell bodies were labeled with FITC-WGA retrogradely transported from the mandibular molar tooth pulp (tooth pulp) and the cutaneous branch of the mylohyoid nerve (cutaneous nerve) in the rat. Tissue sections were then incubated in Hansson's medium for histological demonstration of carbonic anhydrase (CA) activity. About 85% of primary neurons innervating the tooth pulp had medium to large cell bodies (greater than or equal to 300 microns 2 in cross-sectional area), while 77% of those innervating the cutaneous nerve were small (less than 300 microns 2). A total of 32% of the tooth pulp cells exhibited CA activity. CA-containing cells constituted only about 4% of the cutaneous nerve cells. In view of the known distribution of CA within the rodent nervous system, the CA-containing cells are considered to represent the tooth pulp primaries conducting in A-beta velocity range and projecting to rostral subdivisions of the brainstem sensory trigeminal nuclear complex.

Immunohistochemical observation on neuropeptides around the blood vessel in feline dental pulp

Recent advances in immunohistochemistry have revealed the distribution of various neuropeptides in several mammalian dental pulps. These neuropeptides are substance P, neurokinin A, calcitonin gene-related peptide, vasoactive intestinal polypeptide, and neuropeptide Y. Nerve fibers showing immunoreactivity for these neuropeptides are mainly localized around the pulpal vessels, but some are apart from the blood vessel. The distribution of substance P-, neurokinin A-, and calcitonin gene-related peptide-containing nerve fibers is very similar; it appears that these three neuropeptides may be contained in the same nerve fibers. Denervation experiments indicate that substance P-, neurokinin A- and calcitonin gene-related peptide-containing nerve fibers originate from the trigeminal ganglion and that neuropeptide Y-containing nerve fibers come from the superior cervical ganglion. However, the exact origin of vasoactive intestinal polypeptide-containing fibers still remains unknown. These immunohistochemical data indicate that neuropeptides localized around the blood vessel may play a significant role in the regulation of the blood flow in the dental pulp.

Peptidergic innervation of the temporomandibular disk in the rat

The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.

Histochemical localization of calcium in the enamel organ of rat incisors in early-stage amelogenesis

The localization of calcium in the enamel organ of rapidly-frozen, freeze-substituted rat incisors in early-stage amelogenesis was examined by a histochemical calcium-staining method. In secretory ameloblasts, glyoxal bis(2-hydroxyanil) (GBHA) staining revealed intense red reactions in mitochondria and tubulovesicular structures located throughout the cytoplasm, while no reaction was seen in the nucleus and cytosol, nor along the plasma membranes of the respective cells. No significant GBHA reaction was observed in the intercellular compartment and other cells of the enamel organ. Some granular reactions were localized in the cells of the adjacent connective tissue. Control tests confirmed the specificity of GBHA reactions for calcium. Thus, the present observations provide histochemical evidence indicating an exclusive localization of calcium in mitochondria and tubulovesicular structures of the secretory ameloblast, and support their contributions to the translocation of calcium from the proximal to the distal pole of the cytoplasm.

Substance-P-like immunoreactive subepithelial nerve plexuses in the labial mucosa of the mouse

Substance P (SP)-like immunoreactivity was examined in the lower labial mucosa of the mouse by using the whole-mount technique. The density and design of subepithelial nerve plexuses containing SP differed depending on portions of the lower labial mucosa.

Localization of two distinct acid phosphatases in secretory ameloblasts of rat molar tooth germs

Acid phosphatases were examined histochemically at the light- and electron-microscopic levels using para-nitrophenyl phosphate (pNPP) and beta-glycerophosphate (beta-GP) as substrates. By light microscopy, there was intense activity with pNPP in supranuclear and distal regions of the secretory ameloblast, and moderate or slight activity respectively in those regions with beta-GP. These enzyme activities were less at the late secretory stage of amelogenesis and disappeared at the transitional stage. By electron microscopy, acid phosphatase activity was seen in the trans side cisternae of the Golgi apparatus, in lysosome-like granules, and in small vesicles in the Tomes' processes. The activity with pNPP but not beta-GP was also localized at the plasma membrane (proximal, lateral and distal surface). Activity with beta-GP was completely inhibited by 1 mM sodium tartrate and by 1 mM NaF; activity with pNPP was inhibited by 1 mM NaF and 10 mM sodium tartrate, but not by 1 mM sodium tartrate. Thus there are at least two different acid phosphatases, one tartrate-sensitive and the other 1 mM tartrate-resistant, in the secretory ameloblast; the tartrate-resistant enzyme is plasma-membrane bound.

Budding of small vesicles from the rough-surfaced endoplasmic reticulum in secretory ameloblasts of rat molar tooth germs

The budding of small vesicles from the rough-surfaced endoplasmic reticulum (rER) was examined in the secretory ameloblast of rat molar tooth germs by ordinary fixation or prolonged osmium fixation. The budding of small vesicles from the rER was observed not only at the special region (transitional region) of the rER system, which abutted on the cis-face of the Golgi apparatus, but also at other regions of the rER in the secretory ameloblast. Small vesicles (presumed to be transitional vesicles) were adjacent to the rER, which also showed budding of vesicles. After prolonged osmium treatment, osmium deposits appeared in small vesicles, as well as in the cisternae of the cis saccule of the Golgi apparatus. Small vesicles containing osmium deposits were located at various regions of the cell, including the cis-face of the Golgi apparatus. These findings indicate that the budding of small vesicles from the rER is not restricted to the transitional region of the rER system of the secretory ameloblast, but is found at various regions of the cell. This indicates that newly synthesized proteins may be transferred from the rER cisternae to the transitional vesicles not only in the transitional region of the rER system adjacent to the Golgi apparatus, but also in other regions of the secretory ameloblast.

Electrical stimulation of ligament healing. An experimental study of the patellar ligament of rabbits

To examine the effects of direct electric current on ligament healing in rabbits, a full-thickness defect of the patellar ligament was electrically stimulated for time periods of up to seven weeks. The rabbits were randomly assigned to biomechanical and biochemical studies, and healing was evaluated by these parameters. Electrical stimulation was shown to restore tensile stiffness in a short period of time and to decrease the relative proportion of Type III collagen more rapidly than in the control group. However, electrical stimulation did not change the collagen content of newly formed tissue. Electricity enhances the repair process of the ligament by changing the ratio of collagen types.

An unusual coronal fracture of the body of the hamate bone

A coronal fracture of the body of the hamate is described. Treatment consisted of open reduction and internal fixation with Kirshner wires, and the clinical result was good.

Ultrastructural study of a perineurioma

A case of soft tissue tumor in the left brachialis muscle of a 49-year-old Japanese female patient was studied by electron microscopy. The tumor was diagnosed as intramuscular myxoma by light microscopy, but electron microscopic observation revealed that the tumor almost entirely consisted of cells similar to normal perineurial cells. The tumor cells possessed long, slender cytoplasmic processes covered by well-developed but discontinuous basal laminae, clusters of pinocytotic vesicles, and infrequent intercellular junctions. Perineurial cells have also been observed in other peripheral nerve lesions: neurofibromas, nerve sheath myxomas, and localized hypertrophic neuropathies. However, the term "perineurioma" or "perineurial cell tumor" should be reserved for discrete tumorous masses that are almost entirely composed of perineurial cells without evidence of residual axons, Schwann cells, fibroblasts, or tactile corpusclelike structures. Perineurioma may represent a third category of peripheral nerve sheath tumors, ultrastructurally distinct from schwannomas and neurofibromas.

Effect of colchicine on the transport of precursor enamel protein in secretory ameloblasts studied by 3H-proline radioautography in vitro

The incorporation of 3H-proline into the secretory ameloblasts of rat molar tooth germs cultured with or without colchicine was studied by light and electron microscope radioautography to determine the function of microtubules in the transport of precursor enamel protein from the rough-surfaced endoplasmic reticulum (rER) to the Golgi cisternae. The grain counts over the transitional vesicles, which accumulated in various cellular regions with colchicine treatment, continued to increase with chase time, unlike in controls. At 30 and 90 min chase, these counts were significantly higher than in controls. Moreover, the total grain count over the organelles (rER, pale granules, and transitional vesicles), which are positioned before the Golgi cisternae in the synthetic pathway, maintained a significantly higher level at 90 min chase in colchicine-treated tooth germs than in controls. The transport of synthesized protein to the Golgi cisternae via transitional vesicles was suppressed in colchicine-treated tooth germs. Some grains appeared with time over pale granular materials that appeared in the intercellular spaces of secretory ameloblasts with colchicine treatment. However, at each chase period, the grain count over pale granular materials was not so high as the count over the enamel in control. The present results indicate that colchicine affects the transport of newly synthesized protein from the rER to the Golgi cisterna via transitional vesicles, probably by interfering with the oriented transport related to microtubular function. It is suggested that the microtubular system may be concerned with the movement of the transitional vesicles.

Coexistence of vasoactive intestinal polypeptide- and substance P-like immunoreactivities in the tongue of the guinea pig

Vasoactive intestinal polypeptide (VIP)- and substance P (SP)-like immunoreactivities were examined in the tongue of the guinea pig by using the double immunofluorescence method. Coexistence of VIP- and SP-like immunoreactivities was suggested in many nerve fibers innervating the lingual salivary glands, as well as in a few intralingual ganglionic cells.

A histochemical demonstration of calcium in the maturation stage enamel organ of rat incisors

The location of calcium in a rapid-frozen and freeze-substituted maturation stage enamel organ of the rat incisors was demonstrated by means of the glyoxal bis(2-hydroxyanil) (GBHA) staining method, which formed insoluble red precipitates of calcium-GBHA complex. In the ameloblast layer, highly GBHA-reactive tubulo-vesicular structures corresponding to mitochondria and some other membrane-bound structures were localized in both ruffle-ended and smooth-ended ameloblasts, although no significant GBHA reaction was localized in the nucleus, Golgi region, nor along the plasma membrane of these cells. In addition, numerous granular GBHA reactions appeared exclusively in association with the ruffled border of ruffle-ended ameloblasts. GBHA reactions were positive, but were considerably weaker in papillary cells than in the ameloblast. These observations provide a first published histochemical mapping of calcium in the maturation stage enamel organ, and suggest the active participation of mitochondria in maturation stage ameloblasts in calcium regulation.

Neurokinin A-like immunoreactivity in feline dental pulp: its distribution, origin and coexistence with substance P-like immunoreactivity

The distribution and origin of neurokinin A (NKA)-like immunoreactivity were investigated in feline dental pulp by an indirect immunofluorescence method. NKA-containing nerve fibres with varicosities, which entered the dental pulp via apical foramen, were distributed throughout this tissue. Many NKA-containing nerve fibres were localized around blood vessels, but some were observed apart therefrom. At the odontoblastic layer, thin NKA-containing nerve fibres were observed running straight toward the pulp-predentinal border between odontoblasts. After inferior alveolar nerve section, all NKA-containing nerve fibres disappeared in the dental pulp, while the removal of the superior cervical ganglion resulted in no change in the distribution of these fibres. The correlation of NKA-like immunoreactivity and substance P (SP)-like immunoreactivity was also investigated by double-immunofluorescence technique. The distribution of NKA-containing nerve fibres was very similar to that of SP-containing nerve fibres; it appeared that all NKA-containing nerve fibres contained SP.

Cyclic changes in the properties of maturing enamel in the bovine permanent incisor as revealed by glyoxal bis(2-hydroxyanil) staining

Staining patterns of the surface and interior of maturing enamel of these tooth germs were examined using the glyoxal bis(2-hydroxyanil) (GBHA) solution which chelates with calcium loosely bound to hydroxyapatite to form insoluble red precipitates. An intense red, band-like pattern of GBHA staining, 1-2 mm wide, first appeared on the incisal portion of lingual enamel surface as complete loops, concentrically arranged; these gradually increased in number. Most of the later-formed bands encircled the entire periphery of the maturing enamel surface. GBHA also revealed reactive areas on the labio-lingual, cut and ground surface of maturing enamel, corresponding exactly to the surface GBHA bands. GBHA did not stain EDTA-etched surface enamel, but did reveal regular staining patterns on the ground surface, disclosed after EDTA treatment. These observations suggest an intimate correlation between the properties of interior and surface enamel, at least with regard to the state of local calcium. The maturation of bovine incisor enamel may start at the lingual aspect of the tooth crown.

Occurrence of methionine-enkephalin-like immunoreactive cells in the feline vagus nerve

The occurrence of peptidergic cellular elements in the feline vagus nerve was examined by an immunohistochemical method. Some methionine-enkephalin-like immunoreactive cells were present around a few capillaries within the vagus nerve, whereas substance-P- and vasoactive-intestinal-polypeptide-like immunoreactive cells were not observed. The methionine-enkephalin-like immunoreactive cells had an oval shape and their diameter was 7-10 micron. These cells appeared to be in contact with the pericyte of the capillaries. Though the physiological function of these enkephalin-positive cells is unclear, our findings suggest that they can act as endocrine cells and release methionine-enkephalin into the capillaries.

Histochemical, ultrastructural and X-ray microprobe analytical studies of localization of calcium in the mucous lining of the rat duodenum

Localization of calcium in a rapid frozen and freeze substituted duodenum of normal, starved or calcium-repleted rat was examined using either of the glyoxal bis(2-hydroxyanil) (GBHA) staining method, a sensitive histochemical calcium stain or electron microscopy. In normally-fed rats, a majority of absorptive cells of the duodenum showed numerous discrete red granular GBHA reactions, approximately 1 micron or less in diameter, located primarily along their lateral plasma membranes and within intercellular spaces. Electron microscopy also revealed electron-dense granules, 30-100 nm in diameter, showing a similar distribution as the GBHA granules in the respective absorptive cells, and confirmed their absence in mitochondria and other intracellular compartments. Some of the absorptive cells located exclusively at the tip of each villus contained highly GBHA-reactive tubulo-vesicular structures extending throughout the cytoplasm. However, they displayed virtually no granular GBHA reaction. In these cells, electron microscopy revealed numerous electron-dense granules in the nucleus, mitochondria and in other unidentified organelles. X-ray microprobe analyses of ultrathin sections confirmed the presence of calcium within electron-dense granules associated with both types of absorptive cells. The number and intensity of all GBHA reactions fluctuated according to luminal calcium concentration. In calcium-repleted rats, strong GBHA reactions appeared in a narrow zone of lamina propria at the tip of the villus, overlaid, predominantly, with absorptive cells showing tubulo-vesicular GBHA reactions. These results suggest the existence of distinct types of absorptive epithelial cells in the rat duodenum, with respect to patterns of calcium localization which they display.

Cytochemical study of the Golgi apparatus and related organelles of the secretory ameloblasts of rat molar tooth germs cultured with and without colchicine

The Golgi apparatus and Golgi-associated endoplasmic reticulum lysosome (GERL) were examined in the ameloblasts with a cytochemical marker, osmium impregnation, and two enzyme markers, thiamine pyrophosphatase (TPPase) and acid phosphatase (ACPase). In control cultured germs, osmium deposit appeared in one to two immature side cisternae of Golgi stacks; TPPase activity was restricted in a few mature side cisternae and condensing vacuoles. ACPase activity existed in the GERL and, sometimes, in the mature side-cisternae and condensing vacuoles. These findings show that Golgi stacks of ameloblasts consist of several distinct compartments. In colchicine-treated tooth germs, there were morphological and cytochemical changes in both Golgi stacks and GERL. The Golgi apparatus was fragmented and its stacks were scattered throughout the supranuclear region. In some stacks, the number of osmium-positive cisternae was greater than normal; in others they were absent. TPPase and ACPase activity was absent or diminished. These findings suggest the importance of microtubules in the organization of Golgi complex and GERL in the secretory ameloblast.

Occurrence of substance P-like immunoreactive nerve fibers in Krause corpuscles of the dog's tongue

Substance P-like immunoreactive (SPLI) nerve fibers were demonstrated in the Krause corpuscles of the dog's tongue using the indirect immunofluorescence method and cholinesterase histochemistry. SPLI nerve fibers were often in contact with Krause end bulbs and occasionally entered them. From this result it was suggested that substance P might be involved in sensory mechanism of the Krause apparatus.