Abnormal asymmetries in subcortical brain volume in schizophrenia

Subcortical structures, which include the basal ganglia and parts of the limbic system, have key roles in learning, motor control and emotion, but also contribute to higher-order executive functions. Prior studies have reported volumetric alterations in subcortical regions in schizophrenia. Reported results have sometimes been heterogeneous, and few large-scale investigations have been conducted. Moreover, few large-scale studies have assessed asymmetries of subcortical volumes in schizophrenia. Here, as a work completely independent of a study performed by the ENIGMA consortium, we conducted a large-scale multisite study of subcortical volumetric differences between patients with schizophrenia and controls. We also explored the laterality of subcortical regions to identify characteristic similarities and differences between them. T1-weighted images from 1680 healthy individuals and 884 patients with schizophrenia, obtained with 15 imaging protocols at 11 sites, were processed with FreeSurfer. Group differences were calculated for each protocol and meta-analyzed. Compared with controls, patients with schizophrenia demonstrated smaller bilateral hippocampus, amygdala, thalamus and accumbens volumes as well as intracranial volume, but larger bilateral caudate, putamen, pallidum and lateral ventricle volumes. We replicated the rank order of effect sizes for subcortical volumetric changes in schizophrenia reported by the ENIGMA consortium. Further, we revealed leftward asymmetry for thalamus, lateral ventricle, caudate and putamen volumes, and rightward asymmetry for amygdala and hippocampal volumes in both controls and patients with schizophrenia. Also, we demonstrated a schizophrenia-specific leftward asymmetry for pallidum volume. These findings suggest the possibility of aberrant laterality in neural pathways and connectivity patterns related to the pallidum in schizophrenia.

Immobilization stress reduced the expression of neurotrophins and their receptors in the rat brain

Exposure to stressful events and elevated level of stress hormones are associated with impaired spatial memory and neuronal damage in the hippocampus. These neurons are considered to be maintained by neurotrophins such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) and trk family of neurotrophin receptors. Male Wistar rats (6 weeks old) were exposed to immobilization stress for 8 h and their brains were processed for in situ hybridization histochemistry. Exposure to long-lasting immobilization stress reduced mRNA levels for neurotrophins and their high affinity receptors in the brain, especially in the hippocampus. Our results provide, some new information that may be relevant to the pathogenesis of stress-induced disturbances of memory and learning.

Automatic voxel-based morphometry of structural MRI by SPM8 plus diffeomorphic anatomic registration through exponentiated lie algebra improves the diagnosis of probable Alzheimer Disease

BACKGROUND AND PURPOSE

The necessity for structural MRI is greater than ever to both diagnose AD in its early stage and objectively evaluate its progression. We propose a new VBM-based software program for automatic detection of early specific atrophy in AD.

MATERIALS AND METHODS

A target VOI was determined by group comparison of 30 patients with very mild AD and 40 age-matched healthy controls by using SPM. Then this target VOI was incorporated into a newly developed automated software program independently running on a Windows PC for VBM by using SPM8 plus DARTEL. ROC analysis was performed for discrimination of 116 other patients with AD with very mild stage (n = 45), mild stage (n = 30) and moderate-to-advanced stages (n = 41) from 40 other age-matched healthy controls by using a z score map in the target VOI.

RESULTS

Medial temporal structures involving the entire region of the entorhinal cortex, hippocampus, and amygdala showed significant atrophy in the patients with very mild AD and were determined as a target VOI. When we used the severity score of atrophy in this target VOI, 91.6%, 95.8%, and 98.2% accuracies were obtained in the very mild AD, mild AD, and moderate-to-severe AD groups, respectively. In the very mild AD group, a high specificity of 97.5% with a sensitivity of 86.4% was obtained, and age at onset of AD did not influence this accuracy.

CONCLUSIONS

This software program with application of SPM8 plus DARTEL to VBM provides a high performance for AD diagnosis by using MRI.

Sequential mRNA expression for immediate early genes, cytokines, and neurotrophins in spinal cord injury

In this communication, we demonstrate the sequential expression of endogenous molecules, including immediate early genes (IEGs), cytokines, neurotrophins, and neurotrophin receptors in the injured spinal cord. In the acute phase, expression of IEGs and cytokines mRNAs were rapidly upregulated within 1 h in nonneuronal cells in the lesioned sites and the surrounding spinal white and gray matter. Maximal expression was observed at 1 h for c-fos and TNF-alpha mRNAs, at 3 h for c-jun and IL-6 mRNAs, and at 6 h for IL-1 beta mRNA, and these signals were virtually nondetectable after 6-12 h from the onset of the injury. Some of these genes products may promote the degeneration of damaged cells and tissues, while others may be involved in the subsequent repair processes. In the subacute phase, expression of NGF, BDNF, NT-3, p75LNGFR and Trk B mRNAs began to increase in the nonneuronal cells and neuronal cells from 6 h, and peaked at 24-72 h in the area where expression of mRNAs for IEGs and cytokines overlapped. Signals for IL-6 mRNA were also observed in motoneurons at 24-72 h after the injury, with the suggestion that these molecules may be involved in promoting axonal sprouting in the injured spinal cord. Of further interest was the finding that this upregulation of IL-1 beta, BDNF, and NT-3 mRNAs in injured spinal cord was attenuated by treatment with high dose glucocorticoids, with the suggestion that the downregulation of BDNF and NT-3 might be disadvantageous to survival and axonal sprouting of spinal neurons.

Down-regulation of RFL, the FLO/LFY homolog of rice, accompanied with panicle branch initiation

FLORICAULA (FLO) of Antirrhinum and LEAFY (FLY) of Arabidopsis regulate the formation of floral meristems. To examine whether same mechanisms control floral development in distantly related species such as grasses, we isolated RFL, FLO-LFY homolog of rice, and examined its expression and function. Northern analysis showed that RFL is expressed predominantly in very young panicle but not in mature florets, mature leaves, or roots. In situ hybridization revealed that RFL RNA was expressed in epidermal cells in young leaves at vegetative growth stage. After the transition to reproductive stage, RFL RNA was detected in all layers of very young panicle including the apical meristem, but absent in the incipient primary branches. As development of branches proceeds, RFL RNA accumulation localized in the developing branches except for the apical meristems of the branches and secondary branch primordia. Expression pattern of RFL raised a possibility that, unlike FLO and LFY, RFL might be involved in panicle branching. Transgenic Arabidopsis plants constitutively expressing RFL from the cauliflower mosaic virus 35S promoter were produced to test whether 35S-RFL would cause similar phenotype as observed in 35S-LFY plants. In 35S-RFL plants, transformation of inflorescence meristem to floral meristem was rarely observed. Instead, development of cotyledons, rosette leaves, petals, and stamens was severely affected, demonstrating that RFL function is distinct from that of LFY. Our results suggest that mechanisms controlling floral development in rice might be diverged from that of Arabidopsis and Antirrhinum.

Pituitary adenylate cyclase-activating polypeptide is associated with schizophrenia

Pituitary adenylate cyclase-activating polypeptide (PACAP, ADCYAP1: adenylate cyclase-activating polypeptide 1), a neuropeptide with neurotransmission modulating activity, is a promising schizophrenia candidate gene. Here, we provide evidence that genetic variants of the genes encoding PACAP and its receptor, PAC1, are associated with schizophrenia. We studied the effects of the associated polymorphism in the PACAP gene on neurobiological traits related to risk for schizophrenia. This allele of the PACAP gene, which is overrepresented in schizophrenia patients, was associated with reduced hippocampal volume and poorer memory performance. Abnormal behaviors in PACAP knockout mice, including elevated locomotor activity and deficits in prepulse inhibition of the startle response, were reversed by treatment with an atypical antipsychotic, risperidone. These convergent data suggest that alterations in PACAP signaling might contribute to the pathogenesis of schizophrenia.

Rice phloem thioredoxin h has the capacity to mediate its own cell-to-cell transport through plasmodesmata

Rice (Oryza sativa L.) phloem sieve tubes contain RPP13-1, a thioredoxin h protein that moves around the plant via the translocation stream. Such phloem-mobile proteins are thought to be synthesized in the companion cells prior to being transferred, through plasmodesmata, to the enucleate sieve-tube members. In this study, in-situ hybridization experiments confirmed that expression of RPP13-1 is restricted to companion cells within the mature phloem. To test the hypothesis that RPP13-1 enters the sieve tube, via plasmodesmata, recombinant RPP13-1 was expressed in Escherichia coli, extracted, purified and fluorescently labeled with fluorescein isothiocyanate (FITC) for use in microinjection experiments into tobacco (Nicotiana tabacum L.) mesophyll cells. The FITC-RPP13-1 moved from the injected cell into surrounding cells, whereas the E. coli thioredoxin, an evolutionary homolog of RPP13-1, when similarly labeled and injected, failed to move in this same experimental system. In addition, co-injection of RPP13-1 and FITC-dextrans established that RPP13-1 can induce an increase in plasmodesmal size exclusion limit to a value greater than 9.4 but less than 20 kDa. Nine mutant forms of RPP13-1 were constructed and tested for their capacity to move from cell to cell; two such mutants were found to be incapable of movement. Crystal-structure prediction studies were performed on wild-type and mutant RPP13-1 to identify the location of structural motifs required for protein trafficking through plasmodesmata. These studies are discussed with respect to plasmodesmal-mediated transport of macromolecules within the companion cell-sieve tube complex.

Influence of rapid heating with infrared radiation on RF magnetron-sputtered calcium phosphate coatings

This study evaluated the effect of rapid heating with infrared radiation on the physico-chemical and morphological properties of radio frequent (RF) magnetron-sputtered calcium phosphate (Ca-P) coatings. About 2.5 microm thick Ca-P coatings were deposited on titanium disks and cylinders. These specimens were left untreated or were heat treated by infrared radiation at 300, 400, 500, 600, and 700 degrees C for 4, 7, 11, 17, and 24 s. Subsequently, the specimens were immersed in simulated body fluid (SBF) for 1 day, 1 week, and 5 weeks. X-ray diffraction measurements showed that heating at 500 degrees C or higher resulted in an increase of coating crystallinity. In addition, FT-IR measurements revealed the appearance of OH peaks in the spectra of samples treated at 500-700 degrees C. Electron probe microanalysis showed that after 5 weeks of immersion about 40-50% of the coatings heat treated at 500 and 600 degrees C was maintained. The coatings heat treated at 700 degrees C showed no dissolution at all. On the other hand, as-coated and 300 degrees C treated films were dissolved within 1 day. Scanning electron microscopy of the samples showed that directly after heat treatment no apparent cracks were present in the coatings. On the basis of these findings, we conclude that rapid heating with infrared radiation around 600 degrees C is the best heat treatment for RF magnetron-sputtered coatings.

Ganglioneuroma: computed tomography and magnetic resonance features

12 patients who had histological proven ganglioneuromas were investigated by computed tomography (CT) and magnetic resonance (MR) imaging. CT scans (n = 11), conventional spin-echo MR images (n = 10) and dynamic MR images (n = 5) were acquired. All lesions showed a well defined, oval shape. Five lesions (42%) showed calcification which was punctate in four and coarse in one on CT. CT attenuation was predominantly low in three of 10 (30%) and intermediate in the remaining seven (70%). In all lesions MR signals were mainly of low intensity on T1 weighted images (T1WI) and of high intensity on T2 weighted images (T2WI). Dynamic MR studies in five cases showed a lack of early enhancement but gradual increasing enhancement. One case had a ganglioneuroblastoma component which showed soft-tissue density and coarse calcifications on CT scans, MR images with intermediate intensity on T1WI and T2WI and early enhancement and little washout on dynamic MR images. In conclusion, ganglioneuroma typically shows punctate calcification and low attenuation on CT and marked hyperintensity on T2WI with gradual increasing enhancement on dynamic MR images. If a ganglioneuroma has atypical CT and MR features, coexistence of a malignant component should be considered.

5-HT2A receptor subtype in the peripheral branch of sensory fibers is involved in the potentiation of inflammatory pain in rats

One of the major serotonin (5-HT) receptor subtypes expressed in the rat dorsal root ganglion (DRG) neurons is the 5-HT2A receptor. We have previously shown that 5-HT2A receptors in the peripheral sensory terminals are responsible for 5-HT-induced pain and hyperalgesia. In the present study, we characterized neurons expressing 5-HT2A receptors in the rat DRG neurons by means of in situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and behavioral tests. In situ hybridization on consecutive sections revealed that 5-HT2A receptor mRNA is colocalized with calcitonin-gene related peptide (CGRP) mRNA (100/104; 96.2%) but not with c-Ret mRNA (1/115; 0.9%). Signals for 5-HT2A receptor mRNA were found in 9.4 +/- 2.2% of normal DRG (L5) neurons, most of which were small to medium in size. Four days of complete Freund's adjuvant-induced inflammation of the hindpaw doubled the incidence of 5-HT2A receptor mRNA-expressing neurons to 19.3 +/- 2.8%. The level of 5-HT2A receptor mRNA in DRGs of normal and various pathological conditions was then determined by RT-PCR. The level was up-regulated by peripheral inflammation, but not by axotomy or chronic constriction of the peripheral nerve. Systemic administration of 5-HT2A receptor antagonist (Sarpogrelate HCI) produced analgesic effects on thermal hyperalgesia caused by peripheral inflammation, but failed to attenuate thermal hyperalgesia in chronic constriction injury model. These findings suggest that 5-HT2A receptors are mainly expressed in CGRP-synthesizing small DRG neurons and may be involved in the potentiation of inflammatory pain in the periphery.

Fibroblast growth factor (FGF)-2 directly stimulates mature osteoclast function through activation of FGF receptor 1 and p42/p44 MAP kinase

We previously reported that fibroblast growth factor-2 (FGF-2) acts not only on osteoblasts to stimulate osteoclastic bone resorption indirectly but also on mature osteoclasts directly. In this study, we investigated the mechanism of this direct action of FGF-2 on mature osteoclasts using mouse and rabbit osteoclast culture systems. FGF-2 stimulated pit formation resorbed by isolated rabbit osteoclasts moderately from low concentrations (>/=10(-12) m), whereas at high concentrations (>/=10(-9) m) it showed stimulation on pit formation resorbed by unfractionated bone cells very potently. FGF-2 (>/=10(-12) m) also increased cathepsin K and MMP-9 mRNA levels in mouse and rabbit osteoclasts. Among FGF receptors (FGFR1 to 4) only FGFR1 was detected on isolated mouse osteoclasts, whereas all FGFRs were identified on mouse osteoblasts. FGF-2 (>/=10(-12) m) up-regulated the phosphorylation of cellular proteins, including p42/p44 mitogen-activated protein (MAP) kinase, and increased the kinase activity of immunoprecipitated FGFR1 in mouse osteoclasts. The stimulation of FGF-2 on mouse and rabbit osteoclast functions was abrogated by PD-98059, a specific inhibitor of p42/p44 MAP kinase. These results strongly suggest that FGF-2 acts directly on mature osteoclasts through activation of FGFR1 and p42/p44 MAP kinase, causing the stimulation of bone resorption at physiological or pathological concentrations.

Influence of self-etching primer treatment on the adhesion of resin composite to polished dentin and enamel

OBJECTIVE

This study investigated the effectiveness of the self-etching primer treatment on the adhesion of resin composite to both dentin and enamel.

METHODS

Two types of self-etching primer were prepared. One was an aqueous solution of 2-methacryloyloxyethyl phenyl hydrogen phosphate (Phenyl-P) and 2-hydroxyethyl methacrylate (HEMA), and the other was an aqueous solution of 10-methacryloxydecyl dihydrogen phosphate (MDP) and HEMA. Influence of the concentration of Phenyl-P and MDP, and that of the application time on the adhesiveness were examined by measuring the tensile bond strengths of resin composite to dentin and enamel. The data were analyzed using the analysis of variance and Scheffe's test for multiple comparison among the means.

RESULTS

After the 20P and 30P treatment for 30 s, bond strengths to dentin were significantly higher than those after 5P and 10P treatment for 30 s. The 30M treatment of dentin for 15 s significantly increased the bond strength compared with 5P, 10P and 20P for 15 s. In enamel, bond strength with 30P for 60 s was significantly higher than with 5P for 60 s and 30P for 15 s. The 30M for 60 s resulted in significantly higher bond strength than for 15 s. The smear layers on the dentin and enamel were partially dissolved by the self-etching primer treatment. A hybrid layer with a thickness of 1-1.5 microns was formed in dentin-bonded specimens.

SIGNIFICANCE

The self-etching primer containing Phenyl-P or MDP showed good adhesion to dentin and enamel, and this primer is a promising material for resin composite restoration.

Comparison between partial and minimal medial epicondylectomy combined with decompression for the treatment of cubital tunnel syndrome

We have performed minimal medial epicondylectomy for cubital tunnel syndrome since 1990 to preserve the anterior medial collateral ligament. In this study we compared surgical outcomes between partial medial epicondylectomy (14 patients) and minimal medial epicondylectomy (18 patients) combined with ulnar nerve decompression for the treatment of cubital tunnel syndrome. Mean preoperative Yasutake scores were 57 +/- 17 points (+/-SD) in the partial epicondylectomy group and 60 +/- 15 points in the minimal medial epicondylectomy group. The postoperative scores were 79 +/- 19 points and 87 +/- 10 points, respectively. Both groups had significant improvement in their Yasutake scores following medial epicondylectomy. Similar improvements in motor conduction velocity were observed. There was no significant difference in improvement of either the Yasutake scores or the motor conduction velocity between the 2 groups. Valgus instability of the elbow was significantly greater in the partial epicondylectomy group. We therefore conclude that minimal medial epicondylectomy combined with ulnar nerve decompression is an effective treatment for cubital tunnel syndrome and that a larger excision of the medial epicondyle should be avoided.

Effect of surface roughness and calcium phosphate coating on the implant/bone response

The influence of surface roughness and calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated. Four types of titanium implants, i.e. as-machined, grit blasted, as-machined with Ca-P sputter coating, and grit blasted with Ca-P sputter coating, were prepared. The Ca-P sputter-coating, produced by using the RF magnetron sputter technique, was rapid heat-treated with infrared radiation at 600 degrees C. These implants were inserted into the left and right femoral condyles and the left and right tibial diaphyses of the rabbits. After implantation periods of 2 and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically. Histological evaluation revealed no new bone formation around different implant materials after 2 weeks of implantation. After 12 weeks, bone healing was almost completed. For both tibial and femoral implants, Ca-P coated implants always showed a higher amount of bone contact than either of the non-coated implants. On the other hand, surface roughness improved only the response to implants inserted into the tibial diaphysis. On the basis of these findings, we concluded that 1) deposition of a sputtered Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase, and 2) besides implant surface conditions the bone response is also determined by local implant site conditions.

Clinical and pathological features of children with Henoch-Schoenlein purpura nephritis: risk factors associated with poor prognosis

OBJECTIVE

To clarify the risk factors related to prognosis in patients with Henoch-Schoenlein purpura nephritis (HSPN), we investigated the cases with HSPN on long-term observation.

METHODS

We enrolled 114 patients who had been diagnosed with HSPN from 1974-1997. These patients were divided into 2 groups based upon features at last follow-up. One group, designated "favorable", consisted of 69 patients with normal urine and 25 patients with minor urinary abnormalities, and the second group, designated "unfavorable", consisted of 15 patients with active renal disease and 5 patients with renal failure. The clinical features, laboratory data and pathological findings were investigated in 2 groups.

RESULTS

Nephrotic syndrome, decreased factor XIII activity, hypertension and renal failure at onset were more frequent in "unfavorable" than in "favorable". The rate of glomeruli with crescents, macrophage infiltrations, tubulointerstitial changes and acute exacerbation in "unfavorable" were higher than those in "favorable". There were 5 cases with renal insufficiency, and renal survival rate was 95.6% for over 15 years.

CONCLUSIONS

These results suggest that the above mentioned risk factors play an important role in prognosis of the patients with active renal disease and renal failure.

Molecular cloning and expression of a rat prostaglandin E2 receptor of the EP2 subtype

Prostaglandin E2 (PGE2) is a potent local mediator of cell growth and differentiation in various tissues. The receptors for PGE2 have been classified into four pharmacological subtypes, EP1, EP2, EP3, and EP4, based on the responses to selective agonists and antagonists. We have cloned a functional cDNA for the rat EP2 receptor subtype from a rat lung cDNA library. The rat EP2 receptor cDNA encodes 357 amino acid residues having high homology with the human and mouse EP2 receptors and containing seven putative transmembrane domains. In COS-7 cells transfected with rat EP2 cDNA, specific [3H]PGE2 binding was found with a dissociation constant of 14.9 nM, and this binding was inhibited by unlabeled PGE2 and PGE2 alpha. PGE2 and butaprost, an EP2 selective agonist, were effective in increasing the cAMP level in the COS-7 cell transfectants. Northern blot and RT-PCR analysis showed widespread distribution of the EP2 receptor in various tissues. Higher EP2 expression was found in fetal long bones and calvariae than in adult by RT-PCR and in situ hybridization, suggesting a role for this receptor in rapidly growing skeletal tissue.

Deoxyspergualin in relapsing and refractory Wegener's granulomatosis

OBJECTIVES

Conventional therapy of Wegener's granulomatosis with cyclophosphamide and corticosteroids is limited by incomplete remissions and a high relapse rate. The efficacy and safety of an alternative immunosuppressive drug, deoxyspergualin, was evaluated in patients with relapsing or refractory disease.

METHODS

A prospective, international, multicentre, single-limb, open-label study. Entry required active Wegener's granulomatosis with a Birmingham vasculitis activity score (BVAS) > or =4 and previous therapy with cyclophosphamide or methotrexate. Immunosuppressive drugs were withdrawn at entry and prednisolone doses adjusted according to clinical status. Deoxyspergualin, 0.5 mg/kg per day, was self-administered by subcutaneous injection in six cycles of 21 days with a 7-day washout between cycles. Cycles were stopped early for white blood count less than 4000 cells/mm(3). The primary endpoint was complete remission (BVAS 0 for at least 2 months) or partial remission (BVAS <50% of entry score). After the sixth cycle azathioprine was commenced and follow-up continued for 6 months.

RESULTS

42/44 patients (95%) achieved at least partial remission and 20/44 (45%) achieved complete remission. BVAS fell from 12 (4-25), median (range) at baseline to 2 (0-14) at the end of the study (p<0.001). Prednisolone doses were reduced from 20 to 8 mg/day (p<0.001). Relapses occurred in 18 (43%) patients after a median of 170 (44-316) days after achieving remission. Severe or life-threatening (> or = grade 3) treatment-related adverse events occurred in 24 (53%) patients mostly due to leucopaenias.

CONCLUSIONS

Deoxyspergualin achieved a high rate of disease remission and permitted prednisolone reduction in refractory or relapsing Wegener's granulomatosis. Adverse events were common but rarely led to treatment discontinuation.

An experimental study on the "double crush" hypothesis

An experimental study investigated the vulnerability of peripheral nerves in the "double crush" situation. Canine sciatic nerves were studied by means of electrophysiologic and histologic examination. Compression was applied by the KEIO compression clamp, with compression force of 15 g (approximately, 27.6 mm Hg). An incomplete conduction block and mild axonal degeneration were induced by a single compression. However, a complete conduction block and severe axonal degeneration could be induced in half of the cases by the double compression. In these cases, the loss of nerve function after a double lesion was greater than the sum of the deficits after each separate lesion. A good therapeutic effect was obtained by removing all compression, but the effect was incomplete when either compression was retained. It is concluded that proximal compression of a nerve could lessen its ability to withstand further compression more distally.

Deoxyspergualin directly suppresses antibody formation in vivo and in vitro

The effect of deoxyspergualin (DSG, NKT-01) on humoral immunity was investigated both in vitro and in vivo. DSG inhibited the primary and secondary responses to T cell-dependent antigens and the response to T cell-independent antigens in thymic and athymic mice. However, natural antibodies in non-sensitized mice were affected less by the administration of DSG. The agent produced a dose-dependent inhibition of B cell proliferation and antibody production to lipopolysaccharide in vitro. Suppression of secondary antibody response was also shown, whenever antigen stimulation was not given, antibody production was not affected. These results suggest that DSG affects the proliferative stage of B lymphocytes in such a way as to inhibit their growth and antibody production.

Modulation of telomerase activity by zinc in human prostatic and renal cancer cells

Because the up-regulation of telomerase in most cancer tissues is considered to be responsible for the unlimited proliferation of cancer cells, suppression of telomerase activity is an attractive potential target for cancer therapy. The mechanism for the activation of telomerase in cancer cells, however, is still unclear. In the present study, we demonstrated that Zn induces an enhancement of telomerase activity in the human renal cell carcinoma (NRC-12) and prostatic cancer (DU145) cell lines. The maximum elevation of the activity was observed 6 hr after treatment with 100 microM Zn; it was diminished by the addition of either metal chelator or cycloheximide. Other metals such as Cd and Cu also enhanced telomerase activity but to a lesser extent, and no correlation between the activation of telomerase and the induction of metallothionein was observed. Our findings provide the first evidence that metals, especially Zn, can modulate telomerase activity in cancer cells.

Flavonoids from the heartwood of the Thai medicinal plant Dalbergia parviflora and their effects on estrogenic-responsive human breast cancer cells

From the heartwood of Dalbergia parviflora, eight new compounds, khrinones A (1), B (2), C (3), D (4), and E (5), isodarparvinol B (6), dalparvin (7), and (3S)-sativanone (22), along with 32 known compounds, have been isolated and characterized as 17 isoflavones, nine isoflavanones, five flavanones, six isoflavans, and three miscellaneous substances. Isolates were evaluated for their cell proliferation stimulatory activity against the MCF-7 and T47D human breast cancer cell lines, and their luciferase inductive effects using luciferase transiently transfected MCF-7/luc and T47D/luc cells were also determined. Isoflavones such as genistein (10), biochanin A (11), tectorigenin (12), and 2'-methoxyformononetin (13) stimulated the proliferation of both cells, and concentrations of lower than 1 muM of these compounds showed equivalent activity to 10 pM of estradiol (E2). The new isoflavanone (22) also showed activity against both cell types, although it was weaker than that of the corresponding isoflavone (2'-methoxyformononetin, 13). Two optically active isoflavanones (22 and 24: (3S)-violanone) stimulated the proliferation of both cell lines at lower concentrations than three racemates (21: vestitone, 23: 7,3'-dihydroxy-4'-methoxyisoflavanone, and 25: 3-O-methylviolanone). Bowdichione (20), an isoflavone with a quinone structure in its B-ring, showed activity against only one cell line associated with MCF-7 in these assays.

Isolation and characterization of s-myc, a member of the rat myc gene family

A 9-kilobase-pair clone containing a myc-related gene that we have designated s-myc was isolated from a rat genomic library. The entire nucleotide sequence of the cloned DNA was determined, showing that the s-myc gene contains an open reading frame consisting of 1287 base pairs without introns. In vitro transcription-translation analysis of s-myc indicated that this gene produces a protein of approximately 50 kDa. The amino acid sequence predicted from the DNA sequence showed that the s-Myc protein is closely related to the murine N-Myc protein but lacks an acidic amino acid-rich sequence commonly present in the Myc-family proteins. Studies on transfection of s-myc into rat RT4-AC tumor cells revealed that the gene produces a polyadenylylated transcript of approximately 4.7 kilobases and that its high-level expression suppresses the tumor-igenicity of RT4-AC tumor cells in nude mice.