Reduction of PTEN protein and loss of epidermal growth factor receptor gene mutation in lung cancer with natural resistance to gefitinib (IRESSA)

Gefitinib (IRESSA), an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor, has antitumour activity in the advanced non-small-cell lung cancer (NSCLC) setting. However, in chemotherapy-naïve patients with advanced NSCLC, the addition of gefitinib to standard chemotherapy regimens failed to increase survival. These results suggest the need for improved patient selection and combination rationales for targeted therapies. We have identified subpopulations of an adenocarcinoma cell line that are naturally resistant to gefitinib, and have analysed the cDNA expression profiles, genomic status of EGFR gene and the effect of gefitinib on signalling pathways in these cell lines in order to identify key mechanisms for naturally acquired resistance to gefitinib. Gefitinib-resistant subpopulations demonstrated increased Akt phosphorylation (not inhibited by gefitinib), reduced PTEN protein expression and loss of the EGFR gene mutation when compared with parental cell lines. These differences in Akt and PTEN protein expression were not evident from the cDNA array profiles. These data suggests that (1) the EGFR gene mutation may be possibly lost in some cancer cells with other additional mechanisms for activating Akt, (2) reintroduction of PTEN or pharmacological downregulation of the constitutive PI3K-Akt-pathway activity may be an attractive therapeutic strategy in cancers with gefitinib resistance.

NK105, a paclitaxel-incorporating micellar nanoparticle formulation, can extend in vivo antitumour activity and reduce the neurotoxicity of paclitaxel

Paclitaxel (PTX) is one of the most effective anticancer agents. In clinical practice, however, high incidences of adverse reactions of the drug, for example, neurotoxicity, myelosuppression, and allergic reactions, have been reported. NK105, a micellar nanoparticle formulation, was developed to overcome these problems and to enhance the antitumour activity of PTX. Via the self-association process, PTX was incorporated into the inner core of the micelle system by physical entrapment through hydrophobic interactions between the drug and the well-designed block copolymers for PTX. NK105 was compared with free PTX with respect to their in vitro cytotoxicity, in vivo antitumour activity, pharmacokinetics, pharmacodynamics, and neurotoxicity. Consequently, the plasma area under the curve (AUC) values were approximately 90-fold higher for NK105 than for free PTX because the leakage of PTX from normal blood vessels was minimal and its capture by the reticuloendothelial system minimised. Thus, the tumour AUC value was 25-fold higher for NK105 than for free PTX. NK105 showed significantly potent antitumour activity on a human colorectal cancer cell line HT-29 xenograft as compared with PTX (P<0.001) because the enhanced accumulation of the drug in the tumour has occurred, probably followed by its effective and sustained release from micellar nanoparticles. Neurotoxicity was significantly weaker with NK105 than with free PTX. The neurotoxicity of PTX was attenuated by NK105, which was demonstrated by both histopathological (P<0.001) and physiological (P<0.05) methods for the first time. The present study suggests that NK105 warrants a clinical trial for patients with metastatic solid tumours.

Ligand-installed PEGylated bionanosphere

The synthesis of poly(ethylene glycol)-b-poly(2-N,N-dimethylaminoethylmethacrylate) processing an acetal group at the PEG chain end (acetal-PEGPAMA) is reported. The obtained acetal-PEGPAMA block copolymer was found to reduce tetrachloroauric acid at room temperature to produce gold nanoparticles. The size of these nanoparticles was controllable in the range of 6 to 13 nm by changing the initial Au3+: polymer ratio. In addition to the reduction of tetrachloroauric acid, acetal-PEGPAMA bonds on the surface of the obtained gold nanoparticles to improve their dispersion stability in an aqueous medium even at a salt concentration as high as two. Biotinyl-PEGPAMA-anchored gold nanoparticles undergo specific aggregation in the presence of streptavidin thereby revealing their promising utility as colloidal sensing systems for use in biological systems. Biotin-PEGPAMA can also be utilised for the preparation of a functionally PEGylated quantum dot (QD). When CdCl2 and Na2S were mixed in aqueous media in the presence of the biotin-PEGPAMA, a CdS QD with an approximately 5 nm size was prepared. The polyamine segment was anchored onto the surface of the formed CdS nanoparticle, whereas the PEG segment was tethered onto the surface to form a hydrophilic palisade, thus improving the dispersion stability in aqueous media even under a high salt concentration condition. An effective fluorescent resonance energy transfer (FRET) was observed by the specific interaction of the biotin-PEGPAMA stabilised CdS QD with TexasRed-labelled streptavidin with the physiological ionic strength of 0.15 M. The extent of the energy transfer was in proportion to the concentration of the TexasRed-streptavidin. This FRET system using the PEGylated CdS QD coupled with fluorescent-labelled protein can be utilised as a highly sensitive bioanalytical system.

Inhibitory effects of Centella asiatica on azoxymethane-induced aberrant crypt focus formation and carcinogenesis in the intestines of F344 rats

Effects of the water extract of Centella asiatica Linn. on formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF) and intestinal tumorigenesis in male F344 rats were investigated. Treatment with the extract significantly decreased the number of larger ACF (with four or more crypts per focus) in the large intestine in the early stage, while the number of methylated DNA adducts was not decreased compared with that in the AOM-treated group. In the post-initiation stage, the extract significantly decreased the total number of ACF and the number of larger ACF, accompanied by a decrease in the 5-bromo-2'-deoxyuridine-labeling index and an increase in the induction of apoptotic cells in the colonic mucosa. The incidences of neoplasms, the numbers of adenocarcinomas in the small intestines and entire intestines, and sizes of neoplasms in the entire intestines in rats fed C. asiatica extract at a dose of 10 mg/kg were smaller than those in rats given AOM alone (p < 0.05). The extract at a dose of 100 mg/kg significantly reduced the multiplicity of neoplasms in the small intestine (p < 0.05). These results suggest that inhibition of the formation of AOM-induced ACF by C. asiatica extract is associated with modification of cell proliferation and induction of apoptosis in colonic crypts and that the extract has a chemopreventive effect on colon tumorigenesis.

Ileal mucosa-associated lymphoid tissue lymphoma showing several ulcer scars detected using double-balloon endoscopy

A 72-year-old man was admitted to our hospital to undergo a novel small-intestinal endoscopic procedure. He had had occasional episodes of hematochezia over a 2-year period, during which he had been hospitalized twice previously. However, numerous investigations, including hematological and biochemical studies, gastroscopy, colonoscopy, computed tomography, scintigraphy, and angiography had failed to detect the source of bleeding in the gastrointestinal tract. On this admission, double-balloon enteroscopy was performed and revealed several ulcer scars with localized dilation of the ileum. Histopathological examination of the biopsy specimens revealed no abnormal findings. Partial resection of the ileum was performed to prevent further gastrointestinal bleeding, and histopathological examination of the resected specimen revealed aggregation of atypical lymphocytes, predominantly in the muscularis propria layer. Immunohistochemical examination demonstrated that the tumor cells were positive for CD20 and BCL2, but negative for UCHL1. Based on these findings, the lesion was diagnosed as a marginal-zone B-cell lymphoma of mucosa-associated lymphoid tissue. Eighteen months after surgery, the patient was still in complete remission.

Betulinic acid augments the inhibitory effects of vincristine on growth and lung metastasis of B16F10 melanoma cells in mice

We examined the antitumour effect of a combination of betulinic acid (BA) and vincristine (VCR) on murine melanoma B16F10 cells in vitro and in vivo. Betulinic acid, a pentacyclic triterpene, showed a synergistic cytotoxic effect on melanoma cells by combinational use of VCR. Betulinic acid and VCR induced cell cycle arrest at different points (BA at G1 phase and VCR at G2/M phase) and caused apoptosis in B16F10 melanoma cells. In the in vivo study, VCR inhibited metastasis of tumour cells to the lung. The addition of BA to VCR augmented suppression of the experimental lung metastasis of melanoma cells in C57BL/6 mice. The number of lung nodules of more than 1 mm in diameter in mice treated with BA and VCR was less than that in mice treated with VCR alone. These results suggest that BA is an effective supplement for enhancing the chemotherapeutic effect on malignant melanoma.

Clinical assessment of oral malodor by the electronic nose system

A recently developed electronic nose has not yet been clinically applied to evaluations of oral malodor. This investigation sought to determine whether an electronic nose could clinically assess oral malodor. Twenty-nine healthy adults and 49 patients were assessed by results of an actual organoleptic test, a score representing malodor strength with an electronic nose in "top-note" mode (top-note score), and measurements of volatile sulfur compound (VSC) concentrations. The correlation coefficient between top-note and actual organoleptic scores (r = 0.71) was comparable with the log VSC and actual organoleptic scores (r = 0.63). However, the area under the receiver-operating characteristic plots for top-note score was significantly larger than that for log VSC. In logistic regression analyses with top-note score as a dependent variable, probing depth, tongue coating, and plaque control record each had independent associations. Our findings suggest that the top-note score from an electronic nose examination may be useful for the clinical evaluation of oral malodor.

Novel Collagen Sponge Reinforced with Polyglycolic Acid Fiber Produces Robust, Normal Hair in Murine Hair Reconstitution Model

The hair reconstitution assay is a useful system for studying cell-cell and epithelial-mesenchymal interaction. The current method consists of transplantation of both epidermal and dermal cells, using a silicone chamber placed on an athymic nude mouse. However, because of leakage and tilting of the grafted cells, the rate and area of hair growth vary depending on the chamber. We modified this method by using a collagen sponge as a scaffold and compared two types of collagen sponges, each having different tensile strengths. A conventional collagen sponge disturbed normal hair follicle formation; in contrast, a collagen sponge containing polyglycolic acid (PGA) fiber supported proper restructuring of skin and hair follicles. These data suggested the usefulness of PGA fiber-containing collagen sponges for hair reconstitution in research and clinical applications.

Activation of the phosphatidylinositol-3' kinase pathway and DNA synthesis by a mutant insulin-like growth factor I receptor lacking the NPXY motif

We have investigated the role of the NPXY motif in the insulin-like growth factor I receptor (IGF-IR) by focusing on the activation of the phosphatidylinositol-3' kinase (PI3-K) pathway and DNA synthesis following IGF-I stimulation. For this purpose, we established stable R-cell lines, which are deficient in endogenous IGF-IR, and express human IGF-IR lacking the whole NPEY(950) sequence (DeltaNPEY). The DeltaNPEY cells showed an apparent autophosphorylation of IGF-IR, albeit with reduced sensitivity to stimulation compared with cells expressing similar levels of wild-type IGF-IR. Activation of insulin receptor substrate (IRS)-1 and IRS-2 was severely impaired in DeltaNPEY cells even at high concentrations of IGF-I. However, recruitment of p85, a regulatory subunit of PI3-K, to activated IRS-2 was similar between the cell lines, but recruitment of p85 to IRS-1 was reduced in DeltaNPEY cells. Essentially similar levels of p85- or phosphotyrosine-associated PI3-K and Akt activities were observed between the cell lines, although the sensitivity to stimulation was reduced in DeltaNPEY cells. Activation of extracellular signal-regulated kinase and DNA synthesis were virtually unaffected by the mutation, in terms of both sensitivity to stimulation and responsiveness. DNA synthesis was completely inhibited by the PI3-K inhibitor, LY294002. These results indicate that the IGF-IR is able to activate the PI3-K pathway and induce DNA synthesis in a normal fashion without the NPXY motif when the receptor is fully activated.

Differentially expressed Maf family transcription factors, c-Maf and MafA, activate glucagon and insulin gene expression in pancreatic islet alpha- and beta-cells

A basic-leucine zipper transcription factor, MafA, was recently identified as one of the most important transactivators of insulin gene expression. This protein controls the glucose-regulated and pancreatic beta-cell-specific expression of the insulin gene through a cis-regulatory element called RIPE3b/MARE (Maf-recognition element). Here, we show that MafA expression is restricted to beta-cells of pancreatic islets in vivo and in insulinoma cell lines. We also demonstrate that c-Maf, another member of the Maf family of transcription factors, is expressed in islet alpha-cells and in a glucagonoma cell line (alphaTC1), but not in gamma- and delta-cells. An insulinoma cell line, betaTC6, also expressed c-Maf, albeit at a low level. Chromatin immunoprecipitation assays demonstrated that Maf proteins associate with insulin and glucagon promoters in beta- and alpha-cell lines, respectively. c-Maf protein stimulated glucagon promoter activity in a transient luciferase assay, and activation of the glucagon promoter by c-Maf was more efficient than by the other alpha-cell-enriched transcription factors, Cdx2, Pax6, and Isl-1. Furthermore, inhibition of c-Maf expression in alphaTC1 cells by specific short hairpin RNA resulted in marked reduction of the glucagon promoter activity. Thus, c-Maf and MafA are differentially expressed in alpha- and beta-cells where they regulate glucagon and insulin gene expression, respectively.

Inhibition of experimental abdominal aortic aneurysm in the rat by use of decoy oligodeoxynucleotides suppressing activity of nuclear factor kappaB and ets transcription factors

BACKGROUND

Two phenomena, inflammation and matrix degradation, contribute to the progression of abdominal aortic aneurysm (AAA). Importantly, the inflammation is regulated by the transcription factor nuclear factor (NF)-kappaB, whereas the destruction and degradation of elastin fibers by matrix metalloproteinases (MMP) are regulated by ets. Thus, we developed a novel strategy to treat AAA by simultaneous inhibition of both NF-kappaB and ets by using chimeric decoy oligodeoxynucleotides (ODN).

METHODS AND RESULTS

AAA was induced in rats by transient aortic perfusion with elastase, whereas transfection of decoy ODN was performed by wrapping a delivery sheet containing decoy ODN around the aorta. Gel-mobility shift assay at 7 days after treatment demonstrated that both NF-kappaB and ets binding activity were simultaneously inhibited by chimeric decoy ODN. Transfection of chimeric decoy ODN resulted in significant inhibition of the progression of AAA such as aneurysmal dilation at 4 weeks after treatment as compared with control, accompanied by a reduction of MMP expression. Moreover, the destruction of elastin fibers was inhibited in the aorta transfected with chimeric decoy ODN. Importantly, transfection of chimeric decoy ODN demonstrated potent inhibition of aneurysmal dilatation compared with NF-kappaB decoy ODN alone, whereas scrambled decoy ODN had no effects. Interestingly, the migration of macrophages was significantly inhibited by chimeric decoy ODN.

CONCLUSIONS

We demonstrated that inhibition of the progression of AAA was achieved by a novel strategy with chimeric decoy ODN used against NF-kappaB and ets in rat model. NF-kappaB and ets are considered to play an important role in the pathogenesis of AAA.

Isolation and characterization of an alternatively spliced variant of transcription factor Islet-1

The LIM homeodomain protein Islet-1 (Isl1), one of the earliest markers for motor neuron differentiation, is also expressed in all classes of islet cells in the pancreas. Isl1 is known to bind and regulate the promoters of the insulin, glucagon and somatostatin genes. In this study, we describe isolation of a novel isl1 cDNA species from the mouse islet beta cell line betaTC6, which arose from the utilization of an alternative splicing acceptor site in the fifth exon. This shorter cDNA encodes an Isl1 isoform (Isl1-beta) lacking the carboxy-terminal 23 amino acids of the previously reported product Isl1-alpha. Although the level of isl1-beta mRNA is much lower than that of isl1-alpha, isl1-beta is preferentially expressed in murine insulinoma cell lines but not in glucagonoma cell line. Upon transient transfection, both Isl1-alpha and Isl1-beta accumulate in the nuclei of murine insulinoma cells. We found that Isl1-beta is a relatively more potent transcriptional activator of the insulin promoter than Isl1-alpha and that the Isl1-alpha isoform undergoes phosphorylation. Therefore, the transcriptional activity of Isl1 is potentially regulated by the alternative splicing of its mRNA and by phosphorylation.

Sugar-installed block copolymer micelles: their preparation and specific interaction with lectin molecules

Several types of sugar-installed poly(ethylene glycol)/poly(DL-lactide) (sugar-PEG/PLA) block copolymers were synthesized. The synthesized block copolymer forms a core-shell type polymeric micelle in aqueous media possessing sugar molecules on its surface. Specific recognition of lectin proteins with the sugar molecules on the micelle surface was observed. Both the galactose- and lactose-installed micelles specifically interacted with RCA-1; on the other hand the mannose-installed micelle interacted specifically with Con A. With a lectin-immobilized affinity column, the cluster effect of the sugar molecule on the micelle surface was clearly observed.

Glutathione-sensitive stabilization of block copolymer micelles composed of antisense DNA and thiolated poly(ethylene glycol)-block-poly(L-lysine): a potential carrier for systemic delivery of antisense DNA

Glutathione (GSH)-sensitive stabilization of polyion complex (PIC) micelles entrapping antisense oligonucleotide (ODN) was achieved by the reversible cross-linking of the core through disulfide bonds, aiming at the development of a novel DNA carrier system for antisense therapy following systemic administration. Thiolated poly(ethylene glycol)-block-poly(L-lysine) (PEG-thioPLL) and ODN spontaneously associated to form the PIC micelles with the core cross-linked through disulfide bonds. The diameters of the cross-linked micelles were similar to those of the non-cross-linked micelles and were determined to be about 40 nm by light scattering measurements. The micelles have sufficient colloidal stability due to the PEG shell surrounding the core of the polyion complex composed of PLL and ODN. The polyanion exchange studies suggested that the dissociation of the micelles was suppressed through the core cross-linking. The stability of the ODN in the core cross-linked micelles against nuclease was appreciably increased compared to that of free ODN and that in the micelles without cross-linking. On the other hand, the micelles dissociated to release ODN in the presence of GSH at a concentration comparable to the intracellular environment, featuring the potential ability of this system for intracellular ODN delivery.

Survivin inhibits apoptosis in cytotrophoblasts

Survivin, a protein that inhibits apoptosis, is expressed in a variety of tumour cells. We detected survivin-specific mRNA and protein in normal placental tissues, two human choriocarcinoma cell lines (JEG-3 and BeWo), and a trophoblastic cell line (tPA30-1) by reverse transcription-polymerase chain reaction (RT-PCR), Northern blotting, and Western blotting. Immunohistochemically, survivin was localized to normal villous cytotrophoblasts, normal extravillous trophoblasts, cytotrophoblasts in hydatidiform mole, and choriocarcinoma cells. Antisense oligonucleotides for survivin dose-dependently induced apoptosis in two choriocarcinoma cell lines (JEG-3 and BeWo) and a trophoblastic cell line (tPA30-1), while sense oligonucleotides showed little effect. These findings suggest that survivin antagonizes apoptosis in cytotrophoblasts, extravillous trophoblasts, and choriocarcinoma cells.

Peripheral nerve regeneration through alginate gel: analysis of early outgrowth and late increase in diameter of regenerating axons

Our previous study revealed that alginate gel cross-linked with covalent bonds promoted peripheral nerve regeneration in the cat and rat. The present study analyzed nerve regeneration through alginate gel in the early stages within 2 weeks and the late stages up to 21 months after implantation. Four days after surgery, regenerating axons grew without Schwann cell investment through the partially degraded alginate gel, being in direct contact with the alginate without a basal lamina covering. Numerous mast cells infiltrated into the alginate. One to 2 weeks after surgery, regenerating axons were surrounded by common Schwann cells to form small bundles, with some axons at the periphery being partly in direct contact with alginate. At the distal stump, numerous Schwann cells had migrated into the alginate 8-14 days after surgery. They had no basal laminae. The diameter of regenerated myelinated fibers was small (approximately 1 micro m) at 8 weeks, but increased in diameter, having a distribution pattern similar to that of normal nerve 21 months after surgery. Much better nerve regeneration was found in alginate gel-, than collagen sponge-, and fibrin glue-implanted distal stump 12 months after surgery. These results indicate that alginate gel has good biocompatibility for regenerating axon outgrowth and Schwann cell migration, and that regenerated fibers can have a diameter as thick as that of normal fibers in the long term. Alginate gel is a promising material for use as an implant for peripheral nerve regeneration.

Polyion complex micelles as vectors in gene therapy--pharmacokinetics and in vivo gene transfer

To establish non-viral gene delivery systems for intravenous administration, complexes of DNA and block copolymer consisting of poly-L-lysine and poly(ethylene glycol) were tested in in vivo turnover studies. The polyion complex micelles have self-assembling core-shell structures, yielding spherical nano-particles with small absolute values of zeta-potential. Southern blot analysis showed that supercoiled DNA was observed for 30 min and open circular or linear DNA was seen for 3 h after intravenous administration of PIC micelles having the charge ratios of 1:4 and PLL length of 48 mer. The PIC micelles with shorter PLL length showed lower stability in the blood stream suggesting that DNA is able to persist as an intact molecule in the blood stream using this system. Though having no ligands, PIC micelles with charge ratios of 1:2 and 1:4 transfected efficiently into HepG2 cells. Preincubation with free copolymer inhibited expression of the reporter gene, suggesting that adsorption of block copolymer to the cell surface blocked the interaction site of the PIC micelles. When the PIC micelles were injected via supramesenteric vein, expression of the gene was observed only in the liver and was sustained for 3 days. It was suggested that this gene delivery system is intrinsically efficient.

Surface characterization of functionalized polylactide through the coating with heterobifunctional poly(ethylene glycol)/polylactide block copolymers

An AB-type block copolymer composed of alpha-acetalpoly(ethylene glycol) (PEG) as the hydrophilic segment and polylactide (PLA) as the hydrophobic segment was synthesized and utilized to construct a functionalized PEG layer possessing a reactive aldehyde group at the free end of the tethered PEG chain by simple coating on polylactide substrates. Detailed characterization of the functionalized PEGylated surfaces was done from the physicochemical (contact angle and zeta potential) as well as the biological (protein adsorption) point of view to highlight their potential utility as biofunctional interfaces. The amount of protein adsorption was inversely correlated with the degree of water structuring around the PEG molecules, which facilitates the formation of a strongly bound water film to increase the surface hydration. For these surfaces investigated, the extent of surface hydration was more important in determining the materials biocompatibility rather than the actual PEG molecular weight, as evidenced by an extremely low receding contact angle directly related to the adhesive energy of a water molecule. Furthermore, the contact angle relaxation less than a few minutes proved to be determinant for the receding contact angle and resultant hysteresis, caused by rearrangement of the hydrophilic PEG component. Aldehyde groups were confirmed to be present at the tethered PEG chain end using an electron spin resonance probe and can be derivatized with bioactive molecules with amino or hydrazide functionality. The functionalized PEG layer thus prepared on a biodegradable polylactide surface has both nonfouling and ligand-binding properties and may have promising utility as engineered biomaterials including tissue engineering scaffolds.

Long-circulating poly(ethylene glycol)-poly(D,L-lactide) block copolymer micelles with modulated surface charge

Reactive polymeric micelles consisting of an alpha-acetal-poly(ethylene glycol)-poly(D,L-lactide) block copolymer (acetal-PEG-PDLLA) with a narrow size distribution were prepared in this study to conjugate small peptidyl ligands, tyrosine (Tyr) and tyrosyl-glutamic acid (Tyr-Glu), through reductive amination after converting the alpha-acetal group to an aldehyde group, allowing modulation of the surface charge of the micelles from neutral (Tyr-) to anionic (Tyr-Glu-). Both of these micelles showed a significantly long circulating time in the blood compartment with 25% of injected dose still circulating even at 24 h. Further, an appreciably lowered uptake into the liver and spleen was demonstrated for the anionic Tyr-Glu-conjugated PEG-PDLLA micelle compared with a neutral Tyr-conjugated micelle, suggesting a substantial role of the slight anionic charge on the micelle surface in avoiding non-specific organ uptake. Stability of the micelle form in the blood compartment was directly observed for the Tyr-PEG-PDLLA micelle by a gel filtration assay of a plasma sample collected from the micelle-injected mice at 24 h. These results demonstrated that a surface-modulated PEG-PDLLA micelle with a suitable size and a narrowly distributed nature has promising potential as a long-circulating carrier system with desirable biocompatibility and biofunctionality.

Migration, integration, and differentiation of hippocampus-derived neurosphere cells after transplantation into injured rat spinal cord

Hippocampus-derived neurospheres were prepared from transgenic rat fetuses expressing green fluorescent protein (GFP), and transplanted into an alginate-filled lesion of young rat spinal cord. One, two and four weeks after transplantation, a large number of grafted cells survived, many of which expressed immunoreactivity for glial fibrillary acidic protein, and a few expressed immunoreactivity for beta-tubulin III. The grafted cells closely attached to the host tissue including astrocytes at the border of the lesion. It was notable that numerous GFP-positive cells had migrated within host spinal cord tissue up to 2 mm away from the implanted site 4 weeks postoperation. These results demonstrate that rat fetal hippocampus-derived neurosphere cells could survive, differentiate, extensively migrate, and integrate well into the host spinal cord tissue.

The Golgi apparatus of goblet cells in the mouse descending colon: three-dimensional visualization using a confocal laser scanning microscope

The three-dimensional structure of the Golgi apparatus was studied in goblet cells in lectin-stained sections of the mouse descending colon by using a confocal laser scanning microscope. In the lower part of the crypt, the Golgi apparatus formed a dome- or globe-like structure in the supranuclear region. The wall of the dome had some holes, one of which usually faced toward the nucleus and others toward the apical cytoplasm. Mucous granules seemed to be initially released into the interior of the dome and transported toward the apical cytoplasm through the holes. In the upper part of the crypt, on the other hand, the Golgi apparatus formed a cup- or funnel-like structure with a larger opening toward the cell apex and a smaller opening toward the nucleus. A large mass of mucous granules occupied the inside of the cup to the apical cytoplasm. It is thought that the accumulation of mucous granules enlarges holes at the ceiling of the dome to form a large opening, which makes the configuration of the Golgi apparatus cup-shaped.