Spinal fusion and instrumentation for paediatric neuromuscular scoliosis: retrospective review

PURPOSE

A retrospective study was conducted to review the surgical results among 24 patients with neuromuscular scoliosis, who were treated with spinal instrumentation and fusion at the Department of Orthopaedic Surgery, National University Hospital, Singapore between March 1993 and December 1998.

METHODS

We examined complete hospital records of patients who had scoliosis due to aetiologies such as spinal muscular atrophy, cerebral palsy, Duchenne muscular dystrophy, and congenital myopathies. The mean age of patients was 10.6 years (range, 6-14 years) and the mean follow-up duration was 5.5 years.

RESULTS

18 patients had posterior surgery alone, whereas 4 had an anterior release with posterior instrumentation, and 2 had an anterior fusion with instrumentation. The mean length of stay in the intensive care unit was 2 days and the mean duration of hospital stay was 11 days. The mean correction in scoliosis angle ranged from 75.6 degrees to 25.7 degrees. All patients could at least sit without support postoperatively. The one-second forced expiratory volume and forced vital capacity were, in general, maintained throughout the follow-up. There were 2 major complications and 2 minor ones; these were pseudarthrosis with rod breakage requiring revision, deep infection necessitating hardware removal, superficial infection that responded to antibiotics, and urinary tract infection requiring 3 weeks of antibiotic treatment. There were no deaths or any neurological complications after instrumentation.

CONCLUSION

Spinal stabilisation and fusion in children with neuromuscular scoliosis is a safe and effective treatment modality. The effect of surgery on long-term pulmonary function, however, remains controversial and needs to be addressed.

Enhanced expression of transglutaminase 2 in anterior polar cataracts and its induction by TGF-beta in vitro

BACKGROUND/AIMS

Transglutaminase activity has long been implicated in the cataract formation. However, the precise mechanism of how it is produced and involved in this process remains unclear. Here the authors sought to examine whether transglutaminase 2 (TGase 2) is expressed in lens epithelial cells from patients with anterior polar cataracts, to determine whether TGase 2 expression is induced by transforming growth factor (TGF-beta) in cultured lens epithelial cells, and to determine whether TGase 2 participates in the crosslinking of fibronectin in lens epithelial cells in vitro.

METHODS

Lens epithelial cells from anterior polar cataracts, nuclear cataracts, and non-cataractous clear lenses were examined for the expression of TGase 2 using reverse transcription-polymerase chain reaction, western blot analysis, and immunohistochemical analysis. The modulation of extracellular TGase 2 activity by TGF-beta was measured by the formation of fibronectin polymers and the incorporation of fluorescein cadaverine into extracellular matrix proteins. The effect of TGase 2 overexpression was analysed by immunofluorescence staining and western blot analysis of human lens epithelial (HLE) B-3 cells transiently transfected with TGase 2 gene.

RESULTS

The expression of TGase 2 mRNA and its protein was markedly enhanced in lens epithelial cells from patients with anterior polar cataracts. Treatment of HLE B-3 cells with TGF-beta caused an increase in TGase 2 protein, its extracellular activity, and the crosslinking of fibronectin. Transient transfection of HLE B-3 cells with the TGase 2 gene led to the increased production of fibronectin monomers and polymers.

CONCLUSIONS

This study shows that TGase 2 is overexpressed in lens epithelial cells from anterior polar cataracts and that TGF-beta may be a causative factor in the induction of TGase 2. The enhanced expression of TGase 2 might cause the accumulation and crosslinking of the extracellular matrix proteins and might play a part in anterior polar cataract development.

Paediatric orthopaedics in Singapore

This article traces the development of Paediatric Orthopaedics in Singapore. Ever since the formation of the University Department of Orthopaedics in 1952, orthopaedic surgeons have had a special interest in musculoskeletal problems in children. Special clinics called "Congenital Clinics" were held in the Singapore General Hospital to look after these children. These clinics were continued in the Singapore General Hospital after the University Department moved to the National University Hospital in 1985. In 1987, a Division of Paediatric Orthopaedics was formed at the National University Hospital to streamline the care of children with musculoskeletal problems. In 1997, the new KK Women's and Children's Hospital opened with a Department of Orthopaedic Surgery dedicated to paediatric patients. In the space of 50 years Paediatric Orthopaedics has become an established subspecialty in Singapore.

In vivo mesenchymal cell recruitment by a scaffold loaded with transforming growth factor beta1 and the potential for in situ chondrogenesis

The objectives of this study were (1) to develop a biphasic implant made of a bioresorbable polymeric scaffold in combination with TGF-beta1-loaded fibrin glue for tissue-engineering applications, and (2) to determine whether the implant made of a polycaprolactone (PCL) scaffold and TGF-beta1-loaded fibrin glue could recruit mesenchymal cells and induce the process of cartilage formation when implanted in ectopic sites. Twenty-four 6-month-old New Zealand White rabbits were used. Scaffolds loaded with various doses of TGF-beta1 in fibrin glue were implanted subcutaneously, intramuscularly, and subperiosteally. The rabbits were killed and implants were removed at 2, 4, and 6 weeks postoperatively. The specimens were subjected to various staining techniques for histological analysis. Light microscopic examination of all specimens revealed that the entire pore space of the scaffolds was filled with various tissues in each group. The entire volume of the scaffolds in the groups loaded with TGF-beta1 and implanted intramuscularly and subcutaneously was populated with mesenchymal cells surrounded with an abundant extracellular matrix and blood vessels. The scaffold loaded with TGF-beta1 and implanted subperiosteally was found to be richly populated with chondrocytes at 2 and 4 weeks and immature bone formation was identified at 6 weeks. We conclude that scaffolds loaded with TGF-beta1 can successfully recruit mesenchymal cells and that chondrogenesis occurred when this construct was implanted subperiosteally.

mRNA differential display identification of thyroid hormone-responsive protein (THRP) gene in association with early phase of long-term potentiation

The process of long-term potentiation (LTP) consists of the early induction and late maintenance phases. Few studies have examined the cellular mechanisms underlying these two phases; their respective mRNA expression profiles have not yet been elucidated. Here we used the technique of PCR differential display to identify genes that are differentially expressed between the early and late phases of LTP in vivo. Our results indicated that the cDNA fragment corresponding to one mRNA with preferentially increased expression during the early, but not late, phase of LTP encodes the rat thyroid hormone-responsive protein (THRP) gene. In situ hybridization analysis confirmed the results obtained from the PCR differential display. Prior NMDA receptor blockade with MK801 prevented induction of LTP and decreased THRP mRNA expression in the dentate gyrus, as assayed by quantitative RT-PCR analysis. THRP antisense oligonucleotide treatment before tetanic stimulation also prevented induction of LTP. However, when THRP antisense oligonucleotide was administered after induction of LTP, it did not affect expression and maintenance of LTP. THRP is known to be responsive to thyroid hormone. Our results indicate that direct thyroid hormone (T3) injection into the dentate gyrus produces a long-lasting enhancement of synaptic efficacy of these neurons. T3 injection also markedly increased THRP mRNA expression in the dentate gyrus. Taken together, our results suggest that THRP mRNA expression plays an important role in the early phase, but not the late phase, of LTP and that both THRP and thyroid hormone are involved in synaptic plasticity in hippocampal neurons.

Temporospatial sequence of cellular events associated with etoposide-induced neuronal cell death: role of antiapoptotic protein Bcl-X(L)

Etoposide-induced death comprises such nuclear events as the formation of topoisomerase II-DNA cleavable complex and cytosolic events including caspase activation. By first establishing the temporospatial death sequence triggered by etoposide in a neuronal cell line, MN9D overexpressing Bcl-X(L) (MN9D/Bcl-X(L)) or control vector (MN9D/Neo), we examined whether formation of this complex is primarily responsible for cell death and at which strategic points and how Bcl-X(L) blocks etoposide-induced neuronal death. Etoposide induced death that was dependent on caspase, cycloheximide, and calpain in MN9D/Neo cells. Etoposide also induced death in enucleated MN9D/Neo cells, although this was less severe. The level of topoisomerase II-DNA cleavable complex reached at a maximum of 2 hr after etoposide treatment was identical in MN9D/Neo and MN9D/Bcl-X(L) cells. In MN9D/Neo cells, cytochrome c release into the cytosol and caspase activation occurred as early as 2 hr and 3-6 hr after etoposide treatment, respectively. Etoposide-induced DNA laddering potentially via caspase appeared as early as 12 hr after drug treatment, followed by nuclear swelling in MN9D/Neo cells (>18-20 hr). Subsequently, nuclear condensation started by 24-28 hr and became apparent thereafter. All of these events except for nuclear swelling were substantially blocked in MN9D/Bcl-X(L). At the later stage of cell death (<32-36 hr), a specific cleavage of Bax and fodrin appeared that was completely blocked by calpain inhibitor or by Bcl-X(L). Taken together, our data suggest that Bcl-X(L) prevents etoposide-induced neuronal death by exerting its anticaspase and anticalpain effect on cellular events after the formation of topoisomerase II-DNA cleavable complex that may not be a major contributor to cell death.

Therapeutic trial in the first three Asian cases of ethylmalonic encephalopathy: response to riboflavin

Three Korean girls with ethylmalonic encephalopathy, the first Asian cases, were identified. In all three cases, we observed slight improvement in motor functions, cognitive behaviours and chronic mucoid diarrhoea after treatment with riboflavin and/or coenzyme Q10 treatment. The precise pathogenesis of ethylmalonic encephalopathy has not been fully elucidated, but riboflavin treatment may be helpful.

Coccidial contamination of raspberries: mock contamination with Eimeria acervulina as a model for decontamination treatment studies

Numerous outbreaks have been reported since 1995 in the United States and Canada that were linked to the consumption of imported fresh raspberries contaminated with Cyclospora. Because Cyclospora has no laboratory animal hosts, Eimeria acervulina, a common chicken coccidium similar in characteristics to Cyclospora, was used as a surrogate to test decontamination treatments. Raspberries were mock contaminated with E. acervulina-sporulated oocysts in a water suspension, then exposed to washing, freezing, heat, or irradiation before they were fed to chicks. The presence of oocysts in the contaminated raspberries was confirmed either by duodenal lesions or oocysts in cecal contents 5 days postinoculation (PI) or in fecal contents 6 days PI, after 24 h of fecal collection. Washing of raspberries was generally not adequate in removing coccidial contamination, but freezing and heat treatment appeared effective. Gamma irradiation of E. acervulina-sporulated oocysts at a dose of 0.5 kGy was partially effective, but it was completely effective at 1.0 kGy and higher. We suggest that E. acervulina, for mock contamination of raspberries and subsequent decontamination treatments, is easy to handle, safe, and economical to study.

Ultrasound diagnosis of postpartum ovarian vein thrombosis: case report

Postpartum ultrasound investigation of a woman with unremitting fever and right flank pain after Cesarean section revealed an extensive thrombosis of the right ovarian vein which extended into the inferior vena cava. Computed tomography was required to substantiate the diagnosis. Medical treatment with intravenous urokinase and heparin and antibiotics was successfully performed. During the postpartum period, the possibility of ovarian vein thrombosis should be considered in febrile patients with abdominal pain who are not responding to antibiotics, and imaging studies such as ultrasound and computed tomography should be performed early for prompt diagnosis and therapy.

Mucosa-associated lymphoid tissue (MALT) lymphoma combined with tuberculous enteritis at the same site in the jejunum

Mucosa-associated lymphoid tissue (MALT) lymphoma is derived from the marginal zone B-cell compartment and can be found at a wide variety of extranodal sites, most frequently at the gastrointestinal site. Recent clinicopathologic studies suggest a relationship between MALT lymphoma and chronic inflammatory disorders, such as Helicobacter pylori infection in the stomach or autoimmune disorders, such as Sjögren's syndrome in the salivary glands. Primary gastrointestinal MALT lymphomas most commonly arise in the stomach and less often in the small and large intestine. Recently we experienced a case who had MALT lymphoma combined with tuberculous enteritis at the same site (jejunum) confirmed by exploratory laparotomy. We suspect that there may be some relationship between MALT lymphoma and chronic inflammatory process of mycobacterial tuberculous enteritis.

Physeal injury in a lightning strike survivor

Electrical injuries resulting in physeal injury in children are an uncommon but well-recognized clinical entity. Almost all these injuries are sustained from man-made electrical sources. To date, there have been no published cases of growth arrest after lightning strike. The authors report the case of a 12-year-old girl who survived a lightning strike 2 years ago and who presented with asymmetric growth arrest in both legs. The authors discuss the pathophysiology of lightning strike and consider the evidence for direct electrical injury versus ischemic insult to the physis as explanations for the cause of the growth arrest observed in this patient.

Gait and pedobarographic patterns of surgically treated clubfeet

Gait analysis and pedobarography were done on 58 surgically corrected clubfeet in 40 children. The average age of patients at the time of surgery was 6.7 months. The average age of the children at the time of the gait analysis was 6.1 years. Twenty-two children (32 feet) were 5 years old and younger. Eighteen children (26 feet) were older than 5 years old. Cadence, velocity, duration of single-limb stance, step length, and ground reaction force measurements were not significantly different from normal children. Differences noted in clubfeet were: 1) duration of single-limb stance among bilateral clubfeet did not increase with age; 2) increased ankle plantarflexion between opposite foot-strike and toe-off was not present; 3) the feet were internally rotated throughout (toe-in gait); 4) anterior and lateral ground reaction force measurements revealed differing trends with age; and 5) mid- and forefoot pressures increased in the surgically treated group. Gait analysis and pedobarography could detect more subtle abnormalities in corrected clubfeet and provide more objective assessments of persistent deformities.

Overexpression of matrix metalloproteinase-2 mediates phenotypic transformation of lens epithelial cells

Transforming growth factor-beta (TGF-beta) is known to be a causative factor in pathological fibrosis and the metastasis of cancer cells, through effects on molecules of the extracellular matrix (ECM). We evaluated the influence of TGF-beta(1) on the gene expression of matrix metalloproteinase-2 (MMP-2) in lens epithelial cells (LECs). The results showed that TGF-beta(1) induced the expression of mRNA for MMP-2 in LECs. Subsequently, in order to examine the role of MMP-2, we overexpressed MMP-2 in LECs by stable transfection. The MMP-2-overexpressing LECs showed typical indicators of a myofibroblast-like cell phenotype, such as multiple layers of cells, elongated morphology, and expression of alpha-smooth muscle actin. We also showed that an MMP inhibitor blocked the TGF-beta(1)-induced morphological change in LECs. These results demonstrate that MMP-2 plays a role in the transformation of LECs, which has implications for the pathological fibrosis of these cells.

Hydrogen peroxide is a novel inducer of connective tissue growth factor

Connective tissue growth factor (CTGF) has recently been described as a fibrogenic factor and is greatly induced by various extracellular stimuli, such as transforming growth factor-beta (TGF-beta), dexamethasone, and serotonin. CTGF induces collagen type I and fibronectin, and the deposition of such molecules leads to fibrotic disease in many tissues. Intracellular reactive oxygen species (ROS) are generated by extracellular stress conditions and are produced as by-products of cellular metabolism. Imbalanced cellular redox status is a potent pathogenic factor that leads to various degenerative diseases, including tissue fibrosis. Since CTGF is believed to play a crucial role in fibrotic disease formation in many tissues, we examined the role of ROS in CTGF gene expression in human lens epithelial cell line B3. The results showed that CTGF was induced by reactive oxygen species such as hydrogen peroxide and hydroxyl radicals. Next, we examined whether CTGF induction by ROS is via newly synthesized TGF-beta. The results showed that ROS directly induced CTGF mRNA not via the increased TGF-beta synthesis or activation. Next, we treated AG490, which is the well-known inhibitor of Janus kinase (JAK), with hydrogen peroxide. AG490 abrogated the CTGF induction by ROS in a dose-dependent manner. The results suggest that JAK-2/-3 seems to be involved in the enhanced CTGF mRNA expression by hydrogen peroxide. In this report, we present that hydrogen peroxide is a novel inducer of CTGF gene expression and that JAK-2/-3 activation seems to play a role in CTGF induction.

Cleavage of Bax is mediated by caspase-dependent or -independent calpain activation in dopaminergic neuronal cells: protective role of Bcl-2

Two cysteine protease families, caspase and calpain, are known to participate in cell death. We investigated whether a stress-specific protease activation pathway exists, and to what extent Bcl-2 plays a role in preventing drug-induced protease activity and cell death in a dopaminergic neuronal cell line, MN9D. Staurosporine (STS) induced caspase-dependent apoptosis while a dopaminergic neurotoxin, MPP(+) largely induced caspase-independent necrotic cell death as determined by morphological and biochemical criteria including cytochrome c release and fluorogenic caspase cleavage assay. At the late stage of both STS- and MPP(+)-induced cell death, Bax was cleaved into an 18-kDa fragment. This 18-kDa fragment appeared only in the mitochondria-enriched heavy membrane fraction of STS-treated cells, whereas it was detected exclusively in the cytosolic fraction of MPP(+)-treated cells. This proteolytic cleavage of Bax appeared to be mediated by calpain as determined by incubation with [(35)S]methionine-labelled Bax. Thus, cotreatment of cells with calpain inhibitor blocked both MPP(+)- and STS-induced Bax cleavage. Intriguingly, overexpression of baculovirus-derived inhibiting protein of caspase, p35 or cotreatment of cells with caspase inhibitor blocked STS- but not MPP(+)-induced Bax cleavage. This appears to indicate that calpain activation may be either dependent or independent of caspase activation within the same cells. However, cotreatment with calpain inhibitor rescued cells from MPP(+)-induced but not from STS-induced neuronal cell death. In these paradigms of dopaminergic cell death, overexpression of Bcl-2 prevented both STS- and MPP(+)-induced cell death and its associated cleavage of Bax. Thus, our results suggest that Bcl-2 may play a protective role by primarily blocking drug-induced caspase or calpain activity in dopaminergic neuronal cells.

Functional blocking of integrin-associated protein impairs memory retention and decreases glutamate release from the hippocampus

We have previously demonstrated that integrin-associated protein is involved in memory consolidation of one-way inhibitory avoidance learning in rats and mice. In the present study, we examined the effects of functional blocking of integrin-associated protein on memory retention, long-term potentiation and glutamate release in mice as well as on cell attachment to extracellular matrix protein in primary cultures. The results indicated that integrin-associated protein monoclonal antibody miap301, when directly injected into the dentate gyrus of the hippocampus at moderate doses, significantly impairs memory retention in mice in the same one-way inhibitory avoidance task and decreases the amplitude of tetanic stimulation-induced long-term potentiation in dentate gyrus neurons. At a dose that effectively impairs both memory retention and long-term potentiation, integrin-associated protein monoclonal antibody also significantly blocks potassium chloride-induced glutamate release from the hippocampus in vivo. Results from western blot confirmed the presence of integrin-associated protein at the synaptic area. Cell adhesion experiments further revealed that integrin-associated protein monoclonal antibody markedly inhibits granular cell attachment to thrombospondin, the extracellular matrix protein known to bind integrin-associated protein, but not to collagen and laminin, the extracellular matrix proteins known to bind integrin. From these results we suggest that integrin-associated protein monoclonal antibody may impair synaptic plasticity and behavioral plasticity in mice through blockade of granular cell attachment to extracellular matrix protein and the subsequent signal transduction, and through inhibition of glutamate release from the hippocampus.

Decreased susceptibility to azithromycin and erythromycin mediated by a novel mtr(R) promoter mutation in Neisseria gonorrhoeae

During a screen of Neisseria gonorrhoeae clinical isolates obtained in Uruguay for susceptibility to azithromycin, we noticed that approximately 10% of the strains examined displayed decreased susceptibility to azithromycin and erythromycin due to the mtr(CDE)-encoded efflux pump system, but remained susceptible to Triton X-100. We now report that the mtr(R) promoter region of one of these isolates contains a dinucleotide insertion (TT) that mediates this resistance phenotype.

Role of pertussis toxin-sensitive G-proteins in intracellular Ca2+ release and apoptosis induced by inhibiting cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels in HepG2 human hepatoblastoma cells

Previously, we have reported that inhibition of cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels by glibenclamide induced intracellular Ca2+ release from IP(3)-sensitive stores and apoptosis in HepG2 human hepatoblastoma cells (Kim JA, Kang YS, Lee SH, Lee EH, Yoo BH, Lee YS. 1999. Biochem Biophys Res Commun 261:682-688). In this study we investigated the upstream signals involved in the mechanism of these actions of glibenclamide. Treatment with glibenclamide initiated production of inositol 1,4,5-trisphosphate (IP(3)) in a dose- and time-dependent manner. The glibenclamide-induced formation of IP(3) was significantly inhibited by CFTR activators (levamisole and bromotetramisole). The intracellular Ca2+ release and apoptosis induced by glibenclamide were significantly suppressed by treatment with phospholipase C (PLC) inhibitors (U-73122 and manoalide) or by pretreatment with pertussis toxin (PTx). In addition, PTx-catalyzed ADP-ribosylation of GTP-binding proteins (G-proteins) was markedly enhanced by treatment with glibenclamide in a time-dependent manner. Taken together, these results suggest that PTx-sensitive G-proteins coupled to PLCbeta may mediate the intracellular Ca2+ release and apoptosis induced by inhibiting CFTR Cl- channels in HepG2 cells. These results further suggest that the PTx-sensitive G-proteins may be a valuable target for the therapeutic intervention of human hepatomas.

Fatigue and hope: relationships to psychosocial adjustment in Korean women with breast cancer

This study focuses on the relationships of fatigue and hope to psychosocial adjustment of 122 Korean women with breast cancer who received postsurgical chemotherapy or radiation therapy. The results indicated that after controlling for hope, fatigue uniquely accounted for 38% of the variance in psychosocial adjustment. After controlling for fatigue, hope uniquely accounted for 7% of the variance in psychosocial adjustment. However, there was no significant interaction between fatigue and hope in accounting for the variance in psychosocial adjustment. The findings inform clinicians of the importance of fatigue and hope, so that they may consider these factors when planning care for women with breast cancer, especially in women receiving chemotherapy or radiation therapy.

Genetic organization and regulation of antimicrobial efflux systems possessed by Neisseria gonorrhoeae and Neisseria meningitidis

Efflux pumps can make a significant contribution to the capacity of bacteria to resist the action of antibiotics. Certain efflux pumps also recognize antimicrobial agents that are present in their respective hosts and their ability to export toxic agents could enhance bacterial survival during infection prior to appearance of cellular or humoral host defensive systems. This review is concerned with the principal efflux pumps possessed by two closely related strict human pathogens, Neisseria gonorrhoeae and Neisseria meningitidis. Specific emphasis is placed on the organization of the structural genes encoding the mtr and far efflux pumps, the substrates (often host-derived) recognized by these pumps, and the cis- and trans-acting transcriptional factors that regulate efflux pump gene expression in gonococci and meningococci. The overriding theme of this review is that the efflux pumps possessed by these pathogens likely contribute to their pathogenic mechanisms by providing a means to escape a number of antimicrobial compounds that bathe mucosal surfaces.

Malignant solitary fibrous tumor of the pleura causing recurrent hypoglycemia; immunohistochemical stain of insulin-like growth factor i receptor in three cases

We present three cases of malignant solitary fibrous tumors of the pleura (SFTP) that produced recurrent hypoglycemia. Removal of the tumors produced normoglycemia. The tumors were well circumscribed and lobulated, and consisted of firm masses weighing 1,150 g to 1,450 g with the greatest diameter of 15 to 20 cm. The tumors were composed of spindle cells in fascicles or in a haphazard arrangement and were highly cellular and mitotically active (3-8 mitoses/10 high-power fields), showing histologically malignant features. Ultrastructurally, fibroblastic features of the tumor cells were present. Insulin-like growth factors (IGF) have been implicated in the presentation of hypoglycemia. The serum insulin and C-peptide levels were not elevated. Serum IGF-I levels were also low with values of 97.4, 157.1 and 51.9 ng/mL (ref. 125-317 ng/mL), respectively. However, tumor cells were strongly positive for IGF-I receptor on immunohistochemical analysis. It is tempting to speculate that IGF-I contributes to the hypoglycemia, even though the circulating levels were low.

Treatment of Microcotyle sebastis infestation in cultured rockfish Sebastes schlegeli by oral administration of praziquantel in combination with cimetidine

The effect of cimetidine on the treatment efficacy of praziquantel against Microcotyle sebastis infestation in cultured rockfish Sebastes schlegeli was investigated. Juvenile rockfish were divided into 7 groups, and orally administered praziquantel alone (50, 100 and 200 mg kg(-1) body wt, BW) or in combination with cimetidine at a dose of 200 mg kg(-1) BW for each praziquantel dose. The fish in the control group were administered only saline. The results clearly showed that coadministration of cimetidine with praziquantel led to a significantly increased treatment efficacy of the latter drug, and consequently would lead to a lowering of the total dose of praziquantel, and a reduction in the administration times and costs for the treatment of M. sebastis infestation in cultured rockfish.

Blue wild-rye grass competition increases the effect of ozone on ponderosa pine seedlings

Individual ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedlings were grown in mesocosms with three densities of blue wild-rye grass (Elymus glaucus Buckl.) (equivalent to 0, 32 or 88 plants m-2) to determine if the presence of a natural competitor alters the response of ponderosa pine seedlings to ozone. After 3 years of ozone exposure, grass presence reduced total ponderosa pine dry mass by nearly 50%, whereas ozone alone had no significant effect on ponderosa pine growth. The combination of ozone and grass further reduced needle, stem and branch dry mass significantly below that induced by grass competition alone. Root:shoot ratios increased in response to the combined grass and ozone treatments. Grass competition significantly reduced soluble sugar concentrations in all ponderosa pine tissue components examined. Starch concentrations were highly variable but did not differ significantly between treatments. Ozone significantly reduced soluble sugar concentrations in fine roots and stems. In the absence of grass, ozone-treated seedlings tended to have higher tissue N concentrations than controls. In the presence of grass, ozone-treated seedlings had lower N concentrations than controls, resulting in a significant interaction between these two stresses in 1- and 2-year-old needles. Needle C:N ratios decreased in response to grass competition, as a result of increased N concentration and no change in C concentration. The opposite response was observed in ozone-treated seedlings as a result of decreased N concentrations, indicating that ozone-treated seedlings were unable to take up or retain as much nitrogen when grown in the presence of grass. We conclude that ponderosa pine seedlings are more susceptible to ozone when grown in competition with blue wild-rye grass.

Effects of iontophoretically applied substance P, calcitonin gene-related peptide on excitability of dorsal horn neurones in rats

Spontaneous pain, allodynia and hyperalgesia are well known phenomena following peripheral nerve or tissue injury, and it is speculated that secondary hyperalgesia and allodynia, are generally thought to depend on a hyperexcitability (sensitization) of neurons in the dorsal horn. It is supposed that the sensitization may be due to various actions of neurotransmitters (SP, CGRP, excitatory amino acids) released from the primary afferent fibers. In this study, we examined effects of the iontophoretically applied SP and CGRP on the response to EAA receptor agonists (NMDA and non-NMDA) in the WDR dorsal horn neurones and see if the effects of SP or CGRP mimic the characteristic response pattern known in various pain models. The main results are summarized as follows: 1) SP specifically potentiated NMDA response. 2) CGRP non-specifically potentiated both NMDA and AMPA responses. Potentiation of NMDA response, however, was significantly greater than that of AMPA response. 3) 50% of SP applied cells and 15.8% of CGRP applied cells showed reciprocal changes(potentiation of NMDA response and suppression of AMPA response). These results are generally consistent with the sensitization characteristics in diverse pain models and suggests that the modulatory effects of SP and CGRP on NMDA and non-NMDA (AMPA) response are, at least in part, contribute to the development of sensitization in various pain models.

Evaluation of premalignant potential in oral lichen planus using interphase cytogenetics

This study attempted to evaluate whether oral lichen planus (OLP) has the potential to progress to oral squamous cell carcinoma (OSCC) by comparing the degree of genetic instability between clinically-curable OLP and lesions that progressed to OSCC. Fifteen cases of steroid-responsive OLP and two cases of lichenoid dysplasia (LD) that progressed to OSCC were used for this study. Chromosome in situ hybridization (CISH) was performed for chromosomes 9 and 17. The fraction of polysomic and monosomic cells for chromosome 9 increased in mucosal epithelium compared to those of lymphocytes in OLP. This difference was statistically significant (P=0.0017, 0.0054, respectively). Two LD patients showed 15.38% and 22.58% of PI for chromosome 9. In OSCC that developed from LD, the fraction of monosomic cells for chromosome 9 increased by more than 70%. We concluded that LD should be treated as a high-risk premalignant lesion and strongly suggest that the monosomy of chromosome 9 may have a critical role in progress to malignancy from LD.