Cooperative effects of adenoviral vector-mediated interleukin 12 gene therapy with radiotherapy in a preclinical model of metastatic prostate cancer

We investigated the potential benefits of combining adenoviral vector mediated in situ interleukin-12 (AdmIL-12) gene therapy with radiation therapy (XRT) to enhance therapeutic efficacy. In a metastatic mouse prostate cancer cell line, 178-2 BMA, AdmIL-12+XRT demonstrated enhanced therapeutic activities in vitro as determined by clonogenic survival, apoptosis, and mIL-12 levels. At the molecular level, increased expression of tumor necrosis factor-alpha mRNA was specific for the combined therapy. In a subcutaneous 178-2 BMA in vivo model, the combination of AdmIL-12+XRT produced statistically significant tumor growth suppression compared to control vector Adbetagal, Adbetagal XRT, or AdmIL-12 as monotherapy. In addition, significant prolongation of survival was demonstrated for the combination of AdmIL-12+XRT. The combination of AdmIL-12+XRT significantly suppressed both spontaneous and pre-established lung metastases, and led to a prolonged elevation of serum IL-12 and significantly increased natural killer (NK) activities. Importantly, in vivo depletion of NK cells resulted in significant attenuation of the antimetastatic activities of AdmIL-12 alone or AdmIL-12+XRT. These combined effects suggest that AdIL-12 gene therapy together with radiotherapy may achieve maximal tumor control (both local and systemic) in selected prostate cancer patients via radio-gene therapy induced local cytotoxicity and local and systemic antitumor immunity.

Effects of cassia oil on serum and hepatic uric acid levels in oxonate-induced mice and xanthine dehydrogenase and xanthine oxidase activities in mouse liver

We investigated the hypouricemic effects of cassia oil extracted from Cinnamomum cassia using hyperuricemic mice induced by potassium oxonate, and its inhibitory actions against liver xanthine dehydrogenase (XDH) and xanthine oxidase (XOD) activities. Oral administration of cassia oil significantly reduced serum and hepatic urate levels in hyperuricemic mice in a time- and dose-dependent manner. At doses of 450 mg/kg of cassia oil or above, serum urate levels of the oxonate-pretreated mice were not different from the normal control mice. Cassia oil at 600 mg/kg was found to be as potent as allopurinol, which reduced hepatic urate levels to lower than normal. In normal mice, urate levels in liver, but not in serum, were altered with dose-dependent decrease after cassia oil treatment. Furthermore, the ratio, liver uric acid/serum uric acid, was determined after cassia oil administration with time- and dose-dependent decreases in hyperuricemic mice. The positive dose-dependent decrease ratio was also observed after cassia oil treatment in the normal animals. The decreased extent of ratio elicited by cassia oil in normal mice appeared to be greater than that in the hyperuricemic animal. In addition, cassia oil significantly exhibited marked reductions in liver XDH/XOD activities, with an apparent dose-dependence in the normal and hyperuricemic mice. The onset of inhibition in enzyme activities elicited by allopurinol was much higher than that elicited by cassia oil. These results suggested that hypouricemic effects of cassia oil could be explained, at least partly, by inhibiting liver in vivo activities of XDH/XOD.

Neurochemical phenotype of vagal afferent neurons activated to express C-FOS in response to luminal stimulation in the rat

The vagus nerve conveys meal-induced primary afferent responses to the brainstem. Electrophysiological studies indicate that luminal stimuli such as osmolarity and the digestion products of carbohydrates elicit powerful vagal nodose neuronal responses by activating serotonin 3 (5-hydroxytryptamine-3, 5-HT3) receptors on intestinal mucosal afferent fibers. To characterize the neurochemical phenotype of neurotransmitters in vagal nodose neurons that are activated by luminal stimulation, we examined c-fos protein (c-Fos) expression in response to luminal stimulation in conscious rats. A double-labeling technique using antisera to glutamate (Glu), substance P (SP), calcitonin gene-related peptide (CGRP), and somatostatin (SS) was used to determine the neurochemical profile of c-Fos-positive neurons. c-Fos immunoreactivity was insignificant in vehicle-treated rats. Luminal perfusions of NaCl (500 mOsm), tap water (5 mOsm), maltose (300 mmol/l), and 5-HT (10(-5) mol/l) each elicited a significant increase in the number of cells expressing c-Fos. Chronic vagotomy eliminated an increase in nodose neuronal c-Fos expression, and the 5-HT3 receptor antagonist granisetron significantly reduced it. Glu-, SP-, and CGRP-containing neurons represented 28%, 53%, and 19%, respectively, of the total population of nodose neurons. Few neurons contained SS. Double-labeling studies revealed that of the c-Fos-positive neurons responsive to hypertonic NaCl, 52%, 41%, and 3% exhibited immunoreactivity for Glu, SP, and CGRP, respectively. Of those responsive to tap water, 47%, 50%, and 4% exhibited immunoreactivity for Glu-, SP- and CGRP, respectively. In addition, 44%, 38%, and 8% of 5-HT-stimulated and 30%, 32%, and 5% of maltose-stimulated c-Fos-positive neurons exhibited, respectively, Glu, SP, and CGRP immunoreactivity. The few neurons that contained SS did not express c-Fos.

CONCLUSIONS

Vagal primary afferent neurons that respond to 5-HT-dependent luminal stimuli, such as hyperosmolarity and maltose, contain mainly Glu and SP. These neurons appear to play an important role in the mediation of the vago-vagal reflex elicited by luminal stimuli.

An experimental study on biomass air-steam gasification in a fluidized bed

The characteristics of biomass air-steam gasification in a fluidized bed are studied in this paper. A series of experiments have been performed to investigate the effects of reactor temperature, steam to biomass ratio (S/B), equivalence ratio (ER) and biomass particle size on gas composition, gas yield, steam decomposition, low heating value (LHV) and carbon conversion efficiency. Over the ranges of the experimental conditions used, the fuel gas yield varied between 1.43 and 2.57 Nm3/kg biomass and the LHV of the fuel gas was between 6741 and 9143 kJ/Nm3. The results showed that higher temperature contributed to more hydrogen production, but too high a temperature lowered gas heating value. The LHV of fuel gas decreased with ER. Compared with biomass air gasification, the introduction of steam improved gas quality. However, excessive steam would lower gasification temperature and so degrade fuel gas quality. It was also shown that a smaller particle was more favorable for higher gas LHV and yield.

Cellular signaling mechanisms underlying pharmacological action of Bak Foong Pills on gastrointestinal secretion

Bak Foong Pills (BFP, also known as Bai Feng Wan) is an over-the-counter traditional Chinese medicine that has long been used for treating gynecological disorders and improving overall body functions, including gastrointestinal (GI) function. However, the cellular signaling mechanism underlying BFP action, especially on the GI tract, has not been elucidated. In the present study, the human colonic epithelia cell line T(84) was used as a model to investigate the effect of BFP ethanol extract on ion transport in conjunction with the short-circuit current (I(SC)) technique. The results showed that the apical addition of BFP extract produced a concentration-dependent (10-1,000 microg/ml, EC(50) = 120 microg/ml) increase in I(SC). The maximal response was observed at 500 microg/ml with an increase in I(SC) of 24.4 +/- 2.3 microA/cm(2) and apical conductance. The BFP-induced I(SC) was not observed when extracellular Cl(-) was replaced or when treated with Bumetanide (100 microM), an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter. The BFP-induced I(SC) was insensitive to the Na(+) channel blocker, amiloride, but partially inhibited by the Cl(-) channel blocker, DIDS (100 microM), and completely blocked by DPC (2 mM) or glibenclamide (1 mM) with a significant reduction in the apical conductance. The BFP-induced I(SC) could be mimicked by forskolin (10 microM), but inhibited by a pretreatment of the cells with adenylate cyclase inhibitor, MDL-12330A (10 microM). Pretreatment with EGTA (5 mM) and thapsigargin (10 microM) decreased the BFP-induced I(SC) by 10%. These results demonstrated that BFP ethanol extract exerted a stimulatory effect on gastrointestinal Cl(-) secretion by predominantly activating adenylate cyclase and apical cAMP-dependent Cl(-) channels, with minor contributions from calcium-dependent Cl(-) channels. The effect of BFP may be explored to treat GI disorders such as constipation.

Quasiparticle states around a nonmagnetic impurity in a d-density-wave state of high-T(c) cuprates

The electronic structure around a single nonmagnetic impurity in the d-density-wave (DDW) ordering is studied. It is found that a single subgap resonance peak appears in the local density of states around the impurity. In the unitary limit, the position of this resonance peak shifts away from the Fermi energy in accord with the chemical potential. This result is dramatically different from the case of the pure superconducting state for which the impurity resonant energy is approximately pinned at the Fermi level. This can be used to probe the existence of the DDW ordering in cuprates.

Intestinal serotonin acts as paracrine substance to mediate pancreatic secretion stimulated by luminal factors

We recently demonstrated that luminal factors such as osmolality, disaccharides, and mechanical stimulation evoke pancreatic secretion by activating 5-hydroxytryptamine subtype 3 (serotonin-3, 5-HT3) receptors on mucosal vagal afferent fibers in the intestine. We hypothesized that 5-HT released by luminal stimuli acts as a paracrine substance, activating the mucosal vagal afferent fibers to stimulate pancreatic secretion. In the in vivo rat model, luminal perfusion of maltose or hypertonic NaCl increased 5-HT level threefold in intestinal effluent perfusates. Similar levels were observed after intraluminal 10(-5) M 5-HT perfusion. These treatments did not affect 5-HT blood levels. In a separate study, intraduodenal, but not intraileal, 5-HT application induced a dose-dependent increase in pancreatic protein secretion, which was not blocked by the CCK-A antagonist CR-1409. Acute vagotomy, methscopolamine, or perivagal or intestinal mucosal application of capsaicin abolished 5-HT-induced pancreatic secretion. In conscious rats, luminal 10(-5) M 5-HT administration produced a 90% increase in pancreatic protein output, which was markedly inhibited by the 5-HT3 antagonist ondansetron. In conclusion, luminal stimuli induce 5-HT release, which in turn activates 5-HT3 receptors on mucosal vagal afferent terminals. In this manner, 5-HT acts as a paracrine substance to stimulate pancreatic secretion via a vagal cholinergic pathway.

Quasiparticle states at a d-wave vortex core in high- T(c) superconductors: induction of local spin density wave order

The local density of states (LDOS) at the vortex lattice cores in a high- T(c) superconductor is studied by using a self-consistent mean-field theory including interactions for both antiferromagnetism (AF) and d-wave superconductivity (DSC). In a zero-field optimally doped sample the AF order is completely suppressed while DSC prevails. In the mixed state, we show that the local AF-like spin density wave order appears near the vortex core and acts as an effective local magnetic field on electrons via Zeeman coupling. As a result, the LDOS at the core exhibits a double-peak structure near the Fermi level that is in good agreement with recent scanning tunneling microscopy observations.

Temporal and spatial gene expression of major bone extracellular matrix molecules during embryonic mandibular osteogenesis in rats

It is not known how gene expression of bone extracellular matrix molecules is controlled temporally and spatially, or how it is related with morphological differentiation of osteoblasts during embryonic osteogenesis in vivo. The present study was designed to examine gene expressions of type I collagen, osteonectin, bone sialoprotein, osteopontin, and osteocalcin during mandibular osteogenesis using in situ hybridization. Wistar rat embryos 13-20 days post coitum were used. The condensation of mesenchymal cells was formed in 14-day rat embryonic mandibles and expressed genes of pro-alpha 1 (I) collagen, osteonectin, bone sialoprotein and osteopontin. Cuboidal osteoblasts surrounding the uncalcified bone matrix were seen as early as in 15-day embryonic mandibles, while flat osteoblasts lining the surface of the calcified bone were seen from 16-day embryonic mandibles. Cuboidal osteoblasts expressed pro-alpha 1(I) collagen, osteonectin and bone sialoprotein intensely but osteopontin very weakly. In contrast, flat osteoblasts expressed osteopontin very strongly. Osteocytes expressed the extracellular matrix molecules actively, in particular, osteopontin. The present study demonstrated the distinct gene expression pattern of type I collagen, osteonectin, bone sialoprotein, osteopontin and osteocalcin during embryonic mandibular osteogenesis in vivo.

Gene and protein expressions of type I collagen are regulated tissue-specifically in rat hyaline cartilages in vivo

The present study was designed to investigate how rat hyaline cartilages at various sites in vivo express the gene and protein of type I collagen using in situ hybridization and immunohistochemistry. The gene of pro alpha 1(I) collagen was expressed by chondrocytes in articular cartilage, and the protein of type I collagen was identified in the cartilage matrix. In contrast, growth plate cartilage expressed the gene of pro alpha 1(I) collagen, but no protein of type I collagen. Neither gene nor protein of type I collagen was expressed in cartilages of trachea and nasal septum. The present study suggested that expression of type I collagen in hyaline cartilages may be regulated tissue-specifically at gene and/or protein levels.

Distinctive expression of extracellular matrix molecules at mRNA and protein levels during formation of cellular and acellular cementum in the rat

Little is known about differential expression of extracellular matrices secreted by cementoblasts between cellular and acellular cementum. We hypothesize that cementoblasts lining acellular cementum express extracellular matrix genes differently from those lining cellular cementum, thereby forming two distinct types of extracellular matrices. To test this hypothesis, we investigated spatial and temporal gene expression of selected extracellular matrix molecules, that is type I collagen, bone sialoprotein, osteocalcin and osteopontin, during formation of both cellular and acellular cementum using in situ hybridization. In addition, their extracellularly deposited and accumulated proteins were examined immunohistochemically. The mRNA transcripts of pro-alpha1 (I) collagen were primarily localized in cementoblasts of cellular cementum and cementocytes, while those of bone sialoprotein were predominantly seen in cementoblasts lining acellular cementum. In contrast, osteocalcin was expressed by both types of cementoblasts and cementocytes and so was osteopontin but only transiently. Our immunohistochemical examination revealed that translated proteins were localized extracellularly where the genes had been expressed intracellularly. The present study demonstrated the distinctive expression of genes and proteins of the extracellular matrix molecules between cellular and acellular cementum.

Intestinal serotonin acts as a paracrine substance to mediate vagal signal transmission evoked by luminal factors in the rat

The vagus nerve conveys primary afferent information produced by a meal to the brainstem. Serotonin (5-HT), which abounds in intestinal enterochromaffin cells, is released in response to various stimuli. We have recently demonstrated that 5-HT released from intestinal enterochromaffin cells activates 5-HT3 receptors on vagal afferent fibres to mediate luminal non-cholecystokinin-stimulated pancreatic secretion. The present study was designed to evaluate the responses of vagal sensory neurons to intraluminal osmotic stimulation and luminal infusion of maltose, glucose or 5-HT. We investigated the role of endogenous 5-HT in signal transmission evoked by luminal stimuli to activate vagal sensory neurons. The discharges of vagal primary afferent neurons innervating the intestine were recorded from rat nodose ganglia. Luminal factors such as intestinal osmotic stimuli and perfusion of carbohydrates elicited powerful vagal nodose responses. Electrical subdiaphragmatic vagal stimulation activated 364 single units; 40 of these responded to intestinal mucosal stimuli. Of these 40, 30 responded to intraduodenal perfusion of hyperosmolar NaCl (500 mosmol l(-1)), 27 responded to tap water (5 mosmol l(-1)) and 20 and 19 responded to maltose (300 mM) and glucose (277.5 mM), respectively. The 5-HT3/4 antagonist tropisetron (ICS 205-930) or 5-HT3 antagonist granisetron abolished luminal stimuli-evoked nodose neuronal responses. Intraluminal infusion of 10(-5) and 10(-4) M 5-HT elicited increases in vagal afferent discharge in 25 and 31 units, respectively, by activating the 5-HT3 receptors. Acute subdiaphragmatic vagotomy, intestinal mucosal application of the local anaesthetic lidocaine (lignocaine) or administration of 5-HT3 antagonist each abolished the luminal 5-HT-induced nodose neuronal responses. In contrast, distension-sensitive neurons did not respond to duodenal infusion of 5-HT. Pharmacological depletion of 5-HT stores using p-chlorophenylalanine (PCPA), a 5-HT-synthesis inhibitor, abolished luminal factor-stimulated nodose neuronal responses. In contrast, pretreatment with 5,7-dihydroxytryptamine (5,7-DHT), a specific 5-HT neurotoxin that destroys 5-HT-containing neurons without affecting 5-HT-containing mucosal cells, had no effect on these responses. These results suggested that the nodose neuronal responses to luminal osmolarity and to the digestion products of carbohydrates are dependent on the release of endogenous 5-HT from the mucosal enterochromaffin cells, which acts on the 5-HT3 receptors on vagal afferent fibres to stimulate vagal sensory neurons.

Annonaceous acetogenins of the seeds from Annona muricata

Muricatenol (1) is a new C37 non-THF ring acetogenin with four hydroxyls and one isolated double bond in the long aliphatic chain. 2,4-cis-Gigantetrocinone (2) and 2,4-trans-gigantetrocinone (3) have been isolated as their acetates by preparative TLC. 2,4-trans-Isoannonacin-10-one (4) and 2,4-trans-isoannonacin (5) have been isolated as only 2,4-trans-form for the first time (no cis-form). Also four known acetogenins, gigantetrocin-A (6), gigantetrocin-B (7), annomontacin (8), gigantetronenin (9) and a mixture of N-fatty acyl tryptamines have been isolated (10). Their structures have been established on the basis of spectral analyses. The CHCl3 fraction of the seeds showed strong antitumor activities.

Quasiparticle localization in disordered d-wave superconductors

An extensive numerical study is reported on the disorder effect in two-dimensional d-wave superconductors with random impurities in the unitary limit. It is found that a sharp resonant peak shows up in the density of states at zero energy and correspondingly the finite-size spin conductance is strongly enhanced which results in a nonuniversal feature in one-parameter scaling. However, all quasiparticle states remain localized, indicating that the resonant density peak alone is not sufficient to induce delocalization. In the weak disorder limit, the localization length is so long that the spin conductance at small sample size is close to the universal value predicted by Lee [Phys. Rev. Lett. 71, 1887 (1993)].

Immunohistochemical localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias in rats

Type I collagen, fibronectin and tenascin C play an important role in regulating early osteoblast differentiation, but the temporal and spatial relationship of their localization during embryonic osteogenesis in vivo is notknown. The present study was designed to localize these three molecules in the dentary of mandibles and tibias in rat embryos using immunohistochemistry. Serial paraffin sections were cut and adjacent sections were processed for von Kossa staining or immunohistochemistry for type I collagen, fibronectin and tenascin C. In the dentary, tenascin C was localized within and around the mesenchymal cell condensation in embryos at 14 days in utero. The bone matrix at 15 days showed immunoreactivity for both type I collagen and fibronectin. The immunoreactivity of type I collagen was persistent, whereas that of fibronectin decreased with age of embryos. In tibias, tenascin C was localized in the perichondral mesenchymal tissue at 17 days. Immunoreactivity for type I collagen was persistent in the bone matrix, whereas the tibial bone showed little immunoreactivity for fibronectin at any embryonic age examined. The present study demonstrated characteristic localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias.

Expression of major bone extracellular matrix proteins during embryonic osteogenesis in rat mandibles

It is not known how bone proteins appear in the matrix before and after calcification during embryonic osteogenesis. The present study was designed to investigate expressions of the five major bone extracellular matrix proteins--i.e. type I collagen, osteonectin, osteopontin, bone sialoprotein and osteocalcin--during osteogenesis in rat embryonic mandibles immunohistochemically, and their involvement in calcification demonstrated by von Kossa staining. Wistar rat embryos 14 to 18 days post coitum were used. Osteogenesis was not seen in 14-day rat embryonic mandibles. Type I collagen was localized in the uncalcifed bone matrix in 15-day mandibles, where no other bone proteins showed immunoreactivity. Osteonectin, osteopontin, bone sialoprotein and osteocalcin appeared almost simultaneously in the calcified bone matrix of 16-day mandibles and accumulated continuously in 18-day mandibles. The present study suggested that type I collagen constitutes the basic framework of the bone matrix upon which the noncollagenous proteins are oriented to lead to calcification, whereas the noncollagenous proteins are deposited simultaneously by osteoblasts and are involved in calcification cooperatively.

A new kinetic model of protein adsorption on suspended anion-exchange resin particles

The kinetics of adsorption of bovine serum albumin on an anion-exchange resin were measured in a batch system using a flow cell and ultraviolet absorbance, as a function of initial liquid-phase protein concentration and solid-to-liquid phase ratio. A new mathematical model for adsorption kinetics is presented that fits the experimental data to give a highly linear relationship with time, following a short transient period. Numerical integration of the differential form of the new composite nonlinear (CNL) kinetic model, containing three independent parameters, is shown to describe the dynamics of batch adsorption much better than alternative lumped parameter models. Although the new model is phenomenological rather than mechanistic, its principal parameter is shown to be a direct linear function of a physically measurable quantity. This study demonstrates that the model can accurately simulate protein concentration-time profiles using parameter estimates derived from correlations over a wide range of initial protein concentrations and phase ratios. The new CNL model is shown to be considerably superior to the Langmuir and solid-film linear kinetic models in this regard, having the additional advantage that an equilibrium isotherm for the system is not required.

Tumor radiosensitization by sustained intratumoral release of bromodeoxyuridine

We have previously reported that the use of the polymer bis(p-carboxyphenoxy)propane-sebacic acid (20:80) for intratumoral delivery of cis-platinum in a mouse tumor model (RIF-1) potentiated the effects of acute and fractionated radiation. This mode of drug delivery seems particularly applicable to the administration of radiosensitizing drugs because an optimum concentration of radiosensitizer can be maintained in the tumor over the prolonged period required for fractionated radiation treatment. We have now investigated, in the same tumor model, radiosensitization by the thymidine analogue bromodeoxyuridine (BrdUrd). BrdUrd (20%, w/w) was incorporated into bis(p-carboxyphenoxy)propane-sebacic acid (20:80) and polymer rods containing the drug implanted in the RIF-1 tumor. Preliminary in vitro studies of the rate of release of BrdUrd from the polymer showed an initial rapid loss over 24 h, followed by a slower release extending over the next 5 days. In experiments in which tumor cells, which had incorporated BrdUrd in vivo from implanted polymer, were excised and a single cell suspension irradiated in vitro radiosensitization indicative of BrdUrd incorporation was associated mainly with an increase in the alpha constant for the linear quadratic model of cell survival. Radiosensitization was seen for tumor cells harvested between 5 and 10 days after polymer implant, a finding that is consistent with results of experiments in which the percentage of cells that had incorporated BrdUrd were measured by flow cytometry at various times after polymer/BrdUrd implant. The proportion of tumor cells positive for BrdUrd was 40-50% between 3 and 8 days after polymer implant. When tumors were irradiated in situ and response measured in terms of tumor growth delay (TGD), radiosensitization was not seen for an acute dose of 16.5 Gy. In contrast, significant radiosensitization was seen for fractionated treatments when polymer/BrdUrd was implanted 3 days before the first radiation dose. For a dose of 5 x 6 Gy, TGD was increased from 22 days for radiation alone to 27 days for radiation plus polymer implant. For 10 x 6 Gy fractions, TGD increased from 45-77 days for those mice in whom the tumor eventually regrew, whereas for 25% of the mice in this group the tumor volume was reduced to a point where it was no longer detectable and there was no recurrence for at least 120 days after treatment.

Development of interglobular dentine in rat molars and its relation to maturation of enamel

The development of interglobular dentine in the first upper and lower molars of Wistar rats aged 3, 7, 14, 21, 42 days was examined histochemically using a lectin, succinyl wheat germ agglutinin (sWGA), which is specific for N-acetyl-D-glucosamine. sWGA stained the interglobular dentine, predentin and Golgi area of odontoblasts. Interglobular dentine was not formed in the first molars of 3-day rats, but appeared in those of 7-day rats near the enamel-free area. In 14-day rats, interglobular dentine was present in most areas of the coronal dentine except the cervical area. At the interface between dentine and predentin, numerous sWGA-negative calcospherites were seen, suggesting that the interglobular dentine is formed actively there. In 21-day rats, the interlobular dentine was more numerous than in 14-day rats. Interglobular dentine was present in the cervical root dentine as well as in the coronal dentine, including the cervical area. The distribution of interglobular dentine in 42-day rats was similar to that in 21-day rats, but fluorescence of sWGA binding was less intense in the former. Because the development of interglobular dentine appeared to be time and position specific its relation to the stages of ameloblasts was analysed. Thin enamel matrix was formed at cusps in molars of 3-day rats and thickness of enamel matrix increased in 7-day rats. In these teeth, the ameloblasts were at the differentiating or secretory stage. The Golgi area and Tomes' processes of the secretory ameloblasts, the cells of intermediate layer and the enamel matrix were weakly positive with sWGA. The epithelial cells at the enamel-free area were also stained with sWGA. In 14-day rats, most of the ameloblasts in the first maxillary molars were at the maturative stage except in the cervical area, where the ameloblasts were at the transitional stage. sWGA stained the distal border and the Golgi area of the maturative ameloblasts as well as the cells of the papillary layer. The distal border of the maturative ameloblasts appeared either thick or thin, suggesting a ruffle-end and smooth-end of the cells. Ameloblasts were absent in the first molars of 21-day rats and the cervical part of the enamel was covered with the stratified epithelium like that of 42-day rats. The present study has demonstrated that interglobular dentine contains sWGA-binding glycoconjugates and the formation of the interglobular dentine is largely associated with the enamel maturation. These results suggest that matrix-to-cell interaction is important for the development of interglobular dentine.