TGFβ4 alleviates the phenotype of Charcot-Marie-Tooth disease type 1A

The duplication of the peripheral myelin protein 22 (PMP22) gene causes a demyelinating type of neuropathy, commonly known as Charcot-Marie-Tooth disease type 1A (CMT1A). Development of effective drugs for CMT1A still remains as an unmet medical need. In the present study, we assessed the role of the transforming growth factor beta 4 (TGFβ4)/Nodal axis in the pathogenesis of CMT1A. First, we identified PMP22 overexpression-induced Nodal expression in Schwann cells, which might be one of the downstream effectors in CMT1A. Administration of Nodal protein at the developmental stage of peripheral nerves induced the demyelinating phenotype in vivo. Second, we further isolated TGFβ4 as an antagonist that could abolish Nodal-induced demyelination. Finally, we developed a recombinant TGFβ4-fragment crystallizable (Fc) fusion protein, CX201, and demonstrated that its application had promyelinating efficacy in Schwann cells. CX201 administration improved the demyelinating phenotypes of CMT1A mouse models at both pre-symptomatic and post-symptomatic stages. These results suggest that the TGFβ4/Nodal axis plays a crucial role in the pathogenesis of CMT1A and might be a potential therapeutic target for CMT1A.

Anomalous muscles and nerves in the hand of a 94-year-old cadaver-A case report

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The additional flexor muscle (Flexor Digiti Minimi Longus m.) passing through Guyon’s canal is the first to be described.

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The anomalous first lumbrical muscle with three origins is the first to be described.

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Berretini’s and Kaplan’s anastomosis was also noted.

Introduction

During an anatomical dissection of the distal upper extremities, numerous muscular and nervous anomalies were found in the forearm and hand of a 94-year-old cadaver. These anomalies are clinically relevant with regard to medical or surgical interventions.

Presentation of case

The presence of a “flexor digiti minimi longus” muscle was observed passing through Guyon’s canal; to our knowledge this passageway has never been previously reported. An aberrant first lumbrical with three origins was noted. Additionally, numerous atypical nerves were found innervating the hand; the dorsal branch of the ulnar nerve contributed to cutaneous innervation of the palm of the hand (Kaplan’s anastomosis), the superficial ulnar nerve provided muscular innervation to the flexor digiti minimi brevis muscle, and two connections between the common palmar digital branches of the median and superficial ulnar nerves were observed (Berrettini anastomosis).

Discussion

Here, we describe an extranumerary muscle associated with the hypothenar group of muscles. We also describe unusual origins of the first lumbrical muscle, and atypical cutaneous and muscular innervation to the palm of the hand.

Conclusion

Clinically, understanding the existence of these anatomical variations may influence medical care or surgical procedures.

Effects of Phalloidin on Hepatic Gene Expression in Mice

An attempt has been made to identify molecular markers of intrahepatic cholestasis in mice employing phalloidin as a cholestatic agent. Phalloidin was administered to BALB/c mice at three predetermined dose: 250 μg/kg, 500 μg/kg, and 1 mg/kg for 1, 3, and 7 days. Liver function was estimated to confirm cholestasis. Histopathological observations on liver were also made to confirm liver injury. Phalloidin at 1 mg/kg for 7 days was found to induce cholestasis. Therefore gene expression studies were confined to this group only. A total of 88 genes were found to be affected by phalloidin. These were the genes associated with cytoskeleton regulation as well as tight junction, focal adhesion, and ATP-binding cassette transporters. Such proteins obstruct the removal of bile components from hepatocytes to the bile canaliculus or blood. Phalloidin treatment did not affect the proteins responsible for cell maintenance or death. The authors show that phalloidin-induced intrahepatic cholestasis is manifested by disturbing the cytoskeleton. The set of genes up-regulated by phalloidin can be considered as molecular markers of intrahepatic cholestasis. The observations are further expected to be helpful in the management of cholestatic pharmaceuticals and associated problems of liver diseases in humans.

Middle East Respiratory Syndrome Infection Control and Prevention Guideline for Healthcare Facilities

Middle East Respiratory Syndrome (MERS) is an acute viral respiratory illness with high mortality caused by a new strain of betacoronavirus (MERS-CoV). Since the report of the first patient in Saudi Arabia in 2012, large-scale outbreaks through hospital-acquired infection and inter-hospital transmission have been reported. Most of the patients reported in South Korea were also infected in hospital settings. Therefore, to eliminate the spread of MERS-CoV, infection prevention and control measures should be implemented with rigor. The present guideline has been drafted on the basis of the experiences of infection control in the South Korean hospitals involved in the recent MERS outbreak and on domestic and international infection prevention and control guidelines. To ensure efficient MERS-CoV infection prevention and control, care should be taken to provide comprehensive infection control measures including contact control, hand hygiene, personal protective equipment, disinfection, and environmental cleaning.

Identification of agents effective against multiple toxins and viruses by host-oriented cell targeting

A longstanding and still-increasing threat to the effective treatment of infectious diseases is resistance to antimicrobial countermeasures. Potentially, the targeting of host proteins and pathways essential for the detrimental effects of pathogens offers an approach that may discover broad-spectrum anti-pathogen countermeasures and circumvent the effects of pathogen mutations leading to resistance. Here we report implementation of a strategy for discovering broad-spectrum host-oriented therapies against multiple pathogenic agents by multiplex screening of drugs for protection against the detrimental effects of multiple pathogens, identification of host cell pathways inhibited by the drug, and screening for effects of the agent on other pathogens exploiting the same pathway. We show that a clinically used antimalarial drug, Amodiaquine, discovered by this strategy, protects host cells against infection by multiple toxins and viruses by inhibiting host cathepsin B. Our results reveal the practicality of discovering broadly acting anti-pathogen countermeasures that target host proteins exploited by pathogens.

Association between information provision and decisional conflict in cancer patients

BACKGROUND

In this study, we aimed to identify demographic and clinical variables that correlate with perceived information provision among cancer patients and determine the association of information provision with decisional conflict (DC).

PATIENTS AND METHODS

We enrolled a total of 625 patients with cancer from two Korean hospitals in 2012. We used the European Organization for Research and Treatment of Cancer (EORTC) quality-of-life questionnaire (QLQ-INFO26) to assess patients' perception of the information received from their doctors and the Decisional Conflict Scale (DCS) to assess DC. To identify predictive sociodemographic and clinical variables for adequate information provision, backward selective logistic regression analyses were conducted. In addition, adjusted multivariate logistic regression analyses were carried out to identify clinically meaningful differences of perceived level of information subscales associated with high DC.

RESULTS

More than half of patients with cancer showed insufficient satisfaction with medical information about disease (56%), treatment (73%), other services (83%), and global score (80%). In multiple logistic regression analyses, lower income and education, female, unmarried status, type of cancer with good prognosis, and early stage of treatment process were associated with patients' perception of inadequate information provision. In addition, Information about the medical tests with high DCS values clarity [adjusted odds ratio (aOR), 0.54; 95% confidence interval (CI) 0.30-0.97] and support (aOR, 0.53; 95% CI 0.33-0.85) showed negative significance. For inadequate information perception about treatments and other services, all 5 DCS scales (uncertainty, informed, values clarity, support, and effective decision) were negatively related. Global score of inadequate information provision also showed negative association with high DCS effective decision (aOR, 0.43; 95% CI 0.26-0.71) and DCS uncertainty (aOR, 0.46; 95% CI 0.27-0.77).

CONCLUSION

This study found that inadequate levels of perceived information correlated with several demographic and clinical characteristics. In addition, sufficient perceived information levels may be related to low levels of DC.

Distant metastatic lesions in patients with differentiated thyroid carcinoma. Clinical implications of radioiodine and FDG uptake

AIM

Many investigators have reported an inverse relationship between iodine and glucose utilization of differentiated thyroid carcinoma (DTC) according to its degree of differentiation; however, not every DTC is compatible with this phenomenon. This study was conducted to evaluate the clinical implication of iodine and glucose uptake at distant metastatic lesions in DTC patients.

PATIENTS, METHODS

64 DTC patients (women 47; mean age 49.9 ± 16.4 years) with distant metastasis who underwent post (131)I treatment whole-body scan (RxWBS) and FDG PET/CT were included in the study. Radioiodine (RAI) and FDG uptake of metastatic lesions were evaluated. TSH stimulated serum thyroglobulin (s-Tg) were obtained.

RESULTS

53 of 64 patients (82.8%) were RAI(+) group, and 37 patients (57.8%) were FDG(+) group. Patients in the RAI(-) group showed a higher rate of FDG uptake than RAI(+) group (100.0% vs. 49.1%, p = 0.002). Patients in the FDG(-) group showed a higher rate of RAI uptake than FDG(+) group (100.0% vs. 70.3%, p = 0.002). Patients with s-Tg < 100 ng/ml were frequently observed in the FDG(-)/RAI(+) group and the FDG(+)/RAI(-) group (p = 0.023). And patients with s-Tg ≥ 500 ng/ml were more frequently observed in the FDG(+)/RAI(+) group, compared with the FDG(+)/RAI(-) group (p = 0.036). Reduced disease-specific survival (DSS) was observed in patients with RAI(-) (p = 0.003), FDG(+) (p = 0.006), SUVmax > 3.6 (p<0.001), and s-Tg > 75.8 ng/ml (p = 0.009). In multivariate analysis, only a SUVmax > 3.6 was significantly predictive of DSS (p = 0.006).

CONCLUSION

An inverse relationship between RAI and FDG uptake, flip-flop phenomenon, was observed in patients with metastatic lesions of DTC. Reduced disease-specific survival was observed in patients with FDG(+), RAI(-) in metastatic lesions, or high s-Tg value.

Bidirectional effect of Wnt signaling antagonist DKK1 on the modulation of anthrax toxin uptake

LRP6, a co-receptor for the morphogen Wnt, aids endocytosis of anthrax complexes. Here we report that Dickkopf1 (DKK1) protein, a secreted LRP6 ligand and antagonist, is also a modulator of anthrax toxin sensitivity. shRNA-mediated gene silencing or TALEN-mediated gene knockout of DKK1 reduced sensitivity of cells to PA-dependent hybrid toxins. However, unlike the solely inhibitory effect on Wnt signaling, the effects of DKK1 overexpression on anthrax toxicity were bidirectional, depending on its endogenous expression and cell context. Fluorescence microscopy and biochemical analyses showed that DKK1 facilitates internalization of anthrax toxins and their receptors, an event mediated by DKK1-LRP6-Kremen2 complex. Monoclonal antibodies against DKK1 provided dose-dependent protection to macrophages from killing by anthrax lethal toxin (LT). Our discovery that DKK1 forms ternary structure with LRP6 and Kremen2 in promoting PA-mediated toxin internalization provides a paradigm for bacterial exploitation of mechanisms that host cells use to internalize signaling proteins.

Calpain-dependent cytoskeletal rearrangement exploited for anthrax toxin endocytosis

The protective antigen component of Bacillus anthracis toxins can interact with at least three distinct proteins on the host cell surface, capillary morphogenesis gene 2 (CMG2), tumor endothelial marker 8, and β1-integrin, and, with the assistance of other host proteins, enters targeted cells by receptor-mediated endocytosis. Using an antisense-based phenotypic screen, we discovered the role of calpains in this process. We show that functions of a ubiquitous Ca(2+)-dependent cysteine protease, calpain-2, and of the calpain substrate talin-1 are exploited for association of anthrax toxin and its principal receptor, CMG2, with higher-order actin filaments and consequently for toxin entry into host cells. Down-regulated expression of calpain-2 or talin-1, or pharmacological interference with calpain action, did not affect toxin binding but reduced endocytosis and increased the survival of cells exposed to anthrax lethal toxin. Adventitious expression of wild-type talin-1 promoted toxin endocytosis and lethality, whereas expression of a talin-1 mutant (L432G) that is insensitive to calpain cleavage did not. Disruption of talin-1, which links integrin-containing focal adhesion complexes to the actin cytoskeleton, facilitated association of toxin bound to its principal cell-surface receptor, CMG2, with higher-order actin filaments undergoing dynamic disassembly and reassembly during endocytosis. Our results reveal a mechanism by which a bacterial toxin uses constitutively occurring calpain-mediated cytoskeletal rearrangement for internalization.

The influence of hospital volume and surgical treatment delay on long-term survival after cancer surgery

BACKGROUND

We conducted a population-based retrospective cohort study to investigate the influence of hospital volume, delay of surgery, and both together on the long-term survival of postoperative cancer patients.

METHODS

Using information from the Korea Central Cancer Registry from 2001 through 2005 and the National Health Insurance claim database, we determined survival for 147 682 patients who underwent definitive surgery for any of six cancers.

RESULTS

Regardless of cancer site, surgical patients in low- to medium-volume hospitals showed significantly worse survival [adjusted hazard ratio (aHR) = 1.36-1.86] than those in high-volume hospitals in multivariable analyses. Among the latter, treatment delays > 1 month were not associated with worse survival for stomach, colon, pancreatic, or lung cancer but were for rectal [aHR = 1.28; 95% confidence interval (CI), 1.17-1.40] and breast (aHR = 1.59; 95% CI, 1.37-1.84) cancer. For patients in low- to medium-volume hospitals, treatment delay was associated with worse survival for all types of cancer (aHR = 1.78-3.81).

CONCLUSION

Our findings suggest that the effect of hospital volume and surgical treatment delay on overall survival of cancer patients should be considered in formulating or revising national health policy.

Variations in the course of the cervical vagus nerve on thyroid ultrasonography

BACKGROUND AND PURPOSE

Only 1 ultrasonography study that described the variation of the VN had been published at the time our research was begun. The purpose of this study was to evaluate the incidence and type of variation in the course of the cervical VN on thyroid ultrasonography.

MATERIALS AND METHODS

From August 2009 to September 2010, 163 consecutive patients were evaluated by sonography for the screening and characterization of thyroid nodules (mean age, 49.0 ± 14.4 years, male:female, 20:143). Two types of variation were defined as follows: 1) anterior variation, when the course of the VNs changed from the typical location to an anterior location in front of the CCA; and 2) medial variation, when the course of the VNs changed from the typical location to a location medial to the CCA (between CCA and thyroid gland). The incidence of the each variation was studied.

RESULTS

Variation in the course of the VN occurred in 5.5% (18/326) of cases. The anterior variation was observed in 4.3% (14/326, right:left = 4:10), and the medial variation was observed in 1.2% (4/326, right:left = 3:1). For both variations, the VN was close to or nearly abutted the thyroid gland after it changed course.

CONCLUSIONS

Variation in the course of the cervical VN could be assessed by ultrasonography. Two variations were observed in 5.5% of cases. The anterior variation was more common than the medial variation.

Risk factors for device-associated infection related to organisational characteristics of intensive care units: findings from the Korean Nosocomial Infections Surveillance System

Device-associated infections (DAIs) have been the major causes of morbidity and mortality of patients in intensive care units (ICUs). This study evaluated the risk factors for DAIs in ICUs. Ninety-six medical or surgical ICUs of 56 hospitals participated in the Korean Nosocomial Infections Surveillance System between July 2007 and June 2008. The occurrence of catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CABSI), and ventilator-associated pneumonia (VAP) were monitored and DAI rates were calculated. Data associated with ICU characteristics were collected and Poisson regression was used for statistical analysis. Rates of CAUTI, CABSI, and VAP were 3.87 per 1000 urinary catheter days, 2.23 per 1000 central line days, and 1.89 per 1000 mechanical ventilator days, respectively. Rates of CAUTI were higher in ICUs in Seoul (P=0.032) and ICUs of major teaching hospitals (P=0.010). The ICUs of university-affiliated hospitals showed lower CAUTI rates (P=0.013). CABSI rates were higher in Seoul (P=0.001) and in medical ICUs (P=0.026). VAP rates were lower in ICUs of hospitals with more than 900 beds compared with hospitals with 400-699 beds (P=0.026). VAP rates were higher in surgical ICUs (P<0.0001) and increased 1.13-fold with each 100-unit increase in beds per infection control professional (P=0.003). The organisational and institutional characteristics of ICUs may influence DAI rates and there is a need for improvement in the incidence of VAP, CAUTI or CABSI.

Synchronous gastric cancer in primary sporadic colorectal cancer patients in Korea

BACKGROUND AND AIMS

Colorectal cancer has been reported to be the malignancy most frequently associated with gastric cancer in Korea. The aim of this study was to define the frequency and clinical characteristics of synchronous gastric cancer detected at preoperative esophagogastroduodenoscopy (EGD) in colorectal cancer patients.

MATERIALS AND METHODS

This prospective study analyzed the EGD results from 1,542 consecutive colorectal cancer patients who underwent surgery from January 2003 to December 2005 at the Center for Colorectal Cancer, National Cancer Center, Korea.

RESULTS

Of the 1,542 cases, 1,155 (74.9%) underwent EGD at our center and 387 underwent EGD at other hospitals within 6 months before surgery. Of the 1,542 cases, synchronous gastric cancers were detected in 31 cases (2.0%). Of these 31 cases, 26 had early gastric cancer (EGC; 83.9%) and 5 had advanced gastric cancer. Ten (38.5%) of the 26 EGC cases were managed using endoscopic mucosal resection. Compared to colorectal cancer patients without synchronous gastric cancer, the group of patients with synchronous gastric cancer was older (65.5+/-9.6 vs 58.4+/-11.3 years, p=0.001) and had a greater proportion of males (77.4 vs 59.4%, p=0.043).

CONCLUSION

This study found that 2% of Korean sporadic colorectal cancer patients had synchronous gastric cancer. A preoperative EGD for colorectal cancer patients is likely to greatly assist in the diagnosis of synchronous gastric cancer at an early stage and the implementation of appropriate minimally invasive treatment.

Thioredoxin reductase is required for growth and regulates entry into culmination of Dictyostelium discoideum

The thioredoxin system, consisting of thioredoxin, thioredoxin reductase and NADPH, has been well established to be critical for the redox regulation of protein function and signalling. To investigate the role of thioredoxin reductase (Trr) in Dictyostelium discoideum, we generated mutant cells that underexpress or overexpress Trr. Trr-underexpressing cells exhibited severe defects in axenic growth and development. Trr-overexpressing (TrrOE) cells formed very tiny plaques on a bacterial lawn and had a lower rate of bacterial uptake. When developed in the dark, TrrOE cells exhibited a slugger phenotype, defined by a prolonged migrating slug stage. Like other slugger mutants, they were hypersensitive to ammonia, which has been known to inhibit culmination by raising the pH of intracellular acidic compartments. Interestingly, TrrOE cells showed defective acidification of intracellular compartments and decreased activity of vacuolar H+-ATPase which functions in the acidification of intracellular compartments. Moreover, biochemical studies revealed that the thioredoxin system can directly reduce the catalytic subunit of vacuolar H+-ATPase whose activity is regulated by reversible disulphide bond formation. Taken together, these results suggest that Dictyostelium Trr may be essential for growth and play a role in regulation of phagocytosis and culmination, possibly through the modulation of vacuolar H+-ATPase activity.

Reduced glutathione levels affect the culmination and cell fate decision in Dictyostelium discoideum

Glutaredoxins have been known to be glutathione-dependent oxidoreductases that participate in the redox regulation of various cellular processes. To understand the role of glutaredoxins in the development, we examined glutaredoxin 1 (Grx1) of Dictyostelium discoideum. Its mRNA was highly accumulated at the mound and the culmination stages. When Grx1-overexpressing cells were developed, their culmination was delayed, and the expression of marker genes for prespore and spore decreased. Interestingly, they had about 1.5-fold higher amount of reduced glutathione (GSH) compared with parental cells and their prolonged migration was repressed by the oxidant such as hydrogen peroxide. To confirm the effect of GSH on the culmination, glutathione reductase (Gsr) was overexpressed or underexpressed. Similar to Grx1-overexpressing cells, Gsr-overexpressing cells contained about 1.5-fold higher amount of GSH and exhibited the delayed culmination. In contrast, the knockdown mutant of Gsr had nearly 50% lower amount of GSH and showed accelerated culmination. Taken together, these data suggest that the culmination of Dictyostelium is controlled by GSH. In addition, the cells having higher GSH levels showed a prestalk tendency in the chimeric slugs with parental cells, indicating that the difference in the amount of GSH may affect the determination of cell fate.

Effects of acetaminophen on hepatic gene expression in mice

Acetaminophen (APAP) is one of the most commonly used drugs for the safe and effective treatment of fever and pain. However, it is a well-established hepatotoxin. The objective of this study was to identify alternation in various genes in liver of mice after administration of low and high doses of APAP. Male C57BL/6J mice received APAP (30 or 300 mg/kg, i.p.). They were sacrificed after 6 hr and 24 hr for assessment of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), total RNA isolation, cDNA microarray analysis and histopathological analysis of liver injury. Low dose of APAP did not cause hepatotoxicity in mice. However, it was toxic at a high dose. Using microarray technology, we selected changed genes more than 1.5 fold. Gene expression changes were recorded even at a low dose treatment with APAP. Six (6) hr after APAP treatment at low dose, 6 genes were up-regulated and 25 genes were down-regulated. However, 24 hr after treatment at low dose 8 genes were up-regulated and 34 genes were down-regulated. 6 hr after of high dose treatment 29 genes were down-regulated and none was up-regulated. A 24 hr treatment with high dose up-regulated 6 genes and down-regulated 18 genes. These expression patterns provide information on high versus low dose mechanisms of APAP toxicity. Gene expression signatures recorded after a nontoxic dose of APAP strongly support the validity of gene expression changes as meaningful markers of hepatotoxicity.

Aspergillus oryzae palBory encodes a calpain-like protease: homology to Emericella nidulans PalB and conservation of functional regions

We have cloned and sequenced genomic DNA of Aspergillus oryzae palBory, orthologue of Emericella nidulans palB, which encodes a calpain-like protease modulating a signal transduction pathway during alkaline adaptation. The deduced amino acid sequence of PalBory is 70.0% identical to PalB over its entire length. The regions with high similarity revealed possible domains important for their function. This is the first step towards understanding the alkaline adaptation mechanism of A. oryzae, which would be very useful in the fermentation industry.

Glutathione is required for growth and prespore cell differentiation in Dictyostelium

Glutathione (GSH) is the most abundant non-protein thiol in eukaryotic cells and acts as reducing equivalent in many cellular processes. We investigated the role of glutathione in Dictyostelium development by disruption of gamma-glutamylcysteine synthetase (GCS), an essential enzyme in glutathione biosynthesis. GCS-null strain showed glutathione auxotrophy and could not grow in medium containing other thiol compounds. The developmental progress of GCS-null strain was determined by GSH concentration contained in preincubated media before development. GCS-null strain preincubated with 0.2 mM GSH was arrested at mound stage or formed bent stalk-like structure during development. GCS-null strain preincubated with more than 0.5 mM GSH formed fruiting body with spores, but spore viability was significantly reduced. In GCS-null strain precultured with 0.2 mM GSH, prestalk-specific gene expression was delayed, while prespore-specific gene and spore-specific gene expressions were not detected. In addition, GCS-null strain precultured with 0.2 mM GSH showed prestalk tendency and extended G1 phase of cell cycle. Since G1 phase cells at starvation differentiate into prestalk cells, developmental defect of GCS-null strain precultured with 0.2 mM GSH may result from altered cell cycle. These results suggest that glutathione itself is essential for growth and differentiation to prespore in Dictyostelium.

Dictyostelium CBP3 associates with actin cytoskeleton and is related to slug migration

Calcium-binding protein 3 (CBP3) expression was up-regulated under the control of the actin 15 promoter and down-regulated by RNA interference in Dictyostelium discoideum. The overexpression of CBP3 accelerated cell aggregation and formed small aggregates and fruiting body. CBP3-inhibited cells showed uneven aggregation and increased slug trail lengths toward the directed light, whereas CBP3-overexpressing cells showed the opposite phenomena. Under dark condition, the enhanced slug trail length was also observed in the CBP3-inhibited cells. Yeast two-hybrid screening identified actin 8 as interacting protein with CBP3. The interaction between CBP3 and actin was confirmed by beta-galactosidase assay and surface plasmon resonance. CBP3 was associated with Triton X-100-insoluble cytoskeleton in the presence of Ca(2+) and the interaction of CBP3 with cytoskeleton was increased by the addition of Ca(2+). Using fluorescence microscopy, CBP3 was also shown to associate with the actin cytoskeleton during development. Subcellular fractionation indicated that CBP3 was enriched in cytosolic fraction. Taken together, these results suggest that CBP3 interacts with actin cytoskeleton and has a role during cell aggregation and slug migration of Dictyostelium.

Calcium-induced conformational changes of the recombinant CBP3 protein from Dictyostelium discoideum

Calcium-binding proteins play various and significant roles in biological systems. Conformational changes in their structures are closely related to their physiological functions. To understand the role of calcium-binding protein 3 (CBP3) in Dictyostelium discoideum, its recombinant proteins were analyzed using circular dichroism (CD) and fluorescence spectroscopy. Gel mobility shift analysis showed that Ca2+ induced a mobility shift of the recombinant CBP3. Far ultra-violet CD spectra and intrinsic fluorescence spectra on CBP3 and its N- and C-terminal domains exhibited that they underwent a conformational rearrangement depending upon Ca2+ binding. Measurement of Ca2+ dissociation constants demonstrated that CBP3 had high affinity toward Ca2+ in the sub-micromolar range and N-terminal domain had higher affinity than C-terminal domain. The changes of fluorescence spectra by an addition of 8-anilino-1-naphthalene sulfonic acid indicated that the hydrophobic patches of CBP3 and its C-terminal domain are likely to be more exposed in the presence of Ca2+. Since the exposure of hydrophobic patches is thermodynamically unfavorable, Ca2+-bound CBP3 may interact with other proteins in vivo. All these data suggest that Ca2+ induces CBP3 to be more favorable conformation to interact with target proteins.

Use of polyurethane with sustained release dexamethasone in delayed adjustable strabismus surgery

AIM

To determine the effect of polyurethane film with sustained release dexamethasone (SRD) in delayed adjustable strabismus surgery.

METHODS

A prospective, masked observer, controlled study was performed in rabbits. Thirty four rabbit eyes were divided into three groups. After recession of the superior rectus muscle (SRM), polyurethane film with or without SRD, or balanced salt solution was applied beneath and over SRM in the polyurethane-dexamethasone group (group P-D), polyurethane group (group P), and the control group (group C), respectively. Delayed adjustment was performed once on each SRM at 4 and 6 weeks postoperatively by a masked observer. The possible length to adjust and the necessary force required for the adjustment, as well as the degree of any adhesions, were also evaluated.

RESULTS

In the control group, adjustment was impossible in all of the eyes at 4 and 6 weeks postoperatively. In group P-D, adjustment was possible in 11 out of 11 eyes (11/11) 4 weeks postoperatively and in 10/11 eyes 6 weeks postoperatively. In group P, adjustment was possible in 9/11 eyes 4 weeks postoperatively and in 10/12 eyes 6 weeks postoperatively.

CONCLUSIONS

Use of polyurethane film with and without SRD could delay adjustment in most eyes for up to 6 weeks postoperatively. Polyurethane is helpful for delaying adjustment in rabbit eyes until 6 weeks postoperatively without the need for frequent topical instillation of steroids.

Microencapsulation of lipid nanoparticles containing lipophilic drug

A polymeric emulsion bead, which consists of core and capsule, was prepared. The core is composed of lipid nanoparticles containing lipophilic drug and semi-interpenetrating networks (semi-IPNs) are prepared to provide the capsule composed of sodium alginate and hydroxypropylmethyl cellulose (HPMC). The lipid nanoparticles were encapsulated into the polymeric emulsion bead with high drug loading efficiency, and lovastatin was used as a model drug. For the application as an oral drug delivery system, the enteric coating was performed with polymeric emulsion bead. The drug release pattern was controlled by the composition of capsule materials and environmental pH.

Self-assembled "nanocubicle" as a carrier for peroral insulin delivery

AIMS/HYPOTHESIS

A patient with (insulin-dependent) diabetes mellitus receives at least one subcutaneous insulin injection a day to maintain low serum glucose concentrations. Since patients' compliance with such dosage regimens is too low, the development of an oral formula is clearly attractive. We present the development of a liquid formula that can be easily dispersed in water to produce particles named "nanocubicles" which efficiently encapsulate insulin.

METHODS

Fasted streptozotocin-induced diabetic rats were administered orally with particles encapsulating insulin, and particles without insulin or soluble insulin in water. Groups of rats were also injected soluble insulin in PBS for control. Blood glucose concentration and insulin concentration were measured 1, 2, 3, 4 and 6 h after the administration of the insulin formulas.

RESULTS

In vitro experiments show that the particles can be taken up by the Caco-2 cells at a high ratio. The serum glucose concentration was controlled for more than 6 h after oral insulin administration but returned to the basal concentration in 3 h when 1 IU/kg of insulin was injected intravenously.

CONCLUSION/INTERPRETATION

Our biocompatible and stable oral insulin formulation is easy to prepare and produces reproducible hypoglycaemic effects, therefore we anticipate clinical acceptance and utilization of this form of insulin therapy.

The genomic structure and expression of MJD, the Machado-Joseph disease gene

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder that is clinically characterized by cerebellar ataxia and various associated symptoms. The disease is caused by an unstable expansion of the CAG repeat in the MJD gene. This gene is mapped to chromosome 14q32.1. To determine its genomic structure, we constructed a contig composed of six cosmid clones and eight bacterial artificial chromosome (BAC) clones. It spans approximately 300kb and includes MJD. We also determined the complete sequence (175,330bp) of B445M7, a human BAC clone that contains MJD. The MJD gene was found to span 48,240bp and to contain 11 exons. Northern blot analysis showed that MJD mRNA is ubiquitously expressed in human tissues, and in at least four different sizes; namely, 1.4, 1.8, 4.5, and 7.5kb. These different mRNA species probably result from differential splicing and polyadenylation, as shown by sequences of the 21 independent cDNA clones isolated after the screening of four human cDNA libraries prepared from whole brain, caudate, retina, and testis. The sequences of these latter clones relative to the MJD gene in B445M7 indicate that there are three alternative splicing sites and eight polyadenylation signals in MJD that are used to generate the differently sized transcripts.

Structural characteristics of size-controlled self-aggregates of deoxycholic acid-modified chitosan and their application as a DNA delivery carrier

Precise control of the size and structure is one critical design parameter of micellar systems for drug delivery applications. To control the size of self-aggregates, chitosan was depolymerized with various amounts of sodium nitrite, and hydrophobically modified with deoxycholic acid to form self-aggregates in aqueous media. Formation and physicochemical characteristics of size-controlled self-aggregates were investigated using dynamic light scattering, fluorescence spectroscopy, and computer simulation method. The size of self-aggregates varied in the range of 130-300 nm in diameter, and their structures were found to depend strongly on the molecular weight of chitosan ranging from 5 to 200 kDa. Due to the chain rigidity of chitosan molecule, the structure of self-aggregates was suggested to be a cylindrical bamboolike structure when the molecular weight of chitosan was larger than 40 kDa, which might form a very poor spherical form of a birdnestlike structure. To explore the potential applications of self-aggregates as a gene delivery carrier, complexes between chitosan self-aggregates and plasmid DNA were prepared and confirmed by measuring the fluorescence intensity of ethidium bromide and electrophoresis on agarose gels. The complex formation had strong dependency on the size and structure of chitosan self-aggregates and significantly influenced the transfection efficiency of COS-1 cells (up to a factor of 10). This approach to control the size and structure of chitosan-derived self-aggregates may find a wide range of applications in gene delivery as well as general drug delivery applications.

Induction of angiogenesis by expression of soluble type II transforming growth factor-beta receptor in mouse hepatoma

The biological effect of transforming growth factor-beta (TGF-beta) is cell type-specific and complex. The precise role of TGF-beta is not clear in vivo. To elucidate the regulation mechanism of endogenous TGF-beta on hepatoma progression, we modified the MH129F mouse hepatoma cell with a retroviral vector encoding the extracellular region of type II TGF-beta receptor (TRII). Soluble TRII (TRIIs) blocked TGF-beta binding to TRII on the membrane of hepatoma cells. Growth of MH129F cells was inhibited by TGF-beta1 treatment; however, soluble TRII-overexpressing cells (MH129F/TRIIs) did not show any change in proliferation after TGF-beta1 treatment. MH129F/TRIIs cells also increased vascular endothelial growth factor (VEGF) expression, endothelial cell migration, and tube formation. Implantation of MH129F/TRIIs cells into C3H/He mice showed the significantly enhanced tumor formation. According to Western blot and protein kinase C assay, the expression of VEGF, KDR/flk-1 receptor, and endothelial nitric-oxide synthase was enhanced, and the phosphorylation activity of protein kinase C was increased up to 3.7-fold in MH129F/TRIIs tumors. Finally, a PECAM-1-stained intratumoral vessel was shown to be 4.2-fold higher in the MH129F/TRIIs tumor. These results indicate that VEGF expression is up-regulated by a blockade of endogenous TGF-beta signaling in TGF-beta-sensitive hepatoma cells and then stimulates angiogenesis and tumorigenicity. Therefore, we suggest that endogenous TGF-beta is a major regulator of the VEGF/flk-1-mediated angiogenesis pathway in hepatoma progression.

Expression of the alpha1D subunit of the L-type voltage gated calcium channel in human liver

Calcium channel blocker is useful for a variety of purposes and is effective for preventing hepatitis elicited by different inducers, suggesting its possible clinical application for treating hepatitis. The alpha1-subunit of the dihydropyridine-sensitive L-type calcium channel is a target of calcium channel blocker. For clinical application of calcium channel blocker, it is important to analyze the expression of the L-type calcium channel in the liver. However, the subtype of the L-type calcium channel alpha1-subunit expressed in the liver was not known. In the present study, the alpha1-subunit of the calcium channel expressed in human liver was systematically analyzed. The alpha1D subunit of the dihydropyridine-sensitive L-type voltage gated calcium channel is expressed relatively strongly in the liver and may play an important role in the liver.

Nitric oxide directly activates large conductance Ca2+-activated K+ channels (rSlo)

We investigated whether nitric oxide (NO) directly activates the cloned alpha-subunit of large conductance Ca2+-activated K+ (Maxi-K) channels from rat brain (rSlo), expressed either in HEK293 cells or Xenopus oocytes. In inside-out patches, the application of S-nitroso-N-acetylpenicillamine (SNAP), a NO-releasing compound, reversibly activated the channel shifting the voltage dependent activation curve of the macroscopic Maxi-K current to the left by about 15 mV. Pretreatment of the patches with N-ethylmaleimide to alkylate free sulfhydryl groups did not prevent the effect of SNAP, suggesting that NO may directly interact with the channels. These results suggest that Maxi-K channels might be one of the physiological targets of NO in the brain.

NC-1500 prevents concanavalin A-induced mice hepatitis without affecting cytokine gene expression

NC-1500 is a dihydropyridine type calcium channel blocker. The effect of NC-1500 on mice concanavalin A-induced hepatitis was examined. Treatment of mice with concanavalin A (Con A) caused elevation of plasma transaminase. Pretreatment of mice with NC-1500 (3, 10 and 30 mg/kg, p.o.) prevented this Con A-induced elevation of plasma transaminase. Treatment of mice with Con A induced tumor necrosis factor-alpha (TNF-alpha) mRNA expression in the liver. However, NC-1500 (30 mg/kg, p.o.) did not affect this Con A-induced TNF-alpha mRNA expression in the liver. The present results showed that NC-1500 inhibited Con A-induced hepatitis without affecting TNF-alpha mRNA expression in the liver.

SCA17, a novel autosomal dominant cerebellar ataxia caused by an expanded polyglutamine in TATA-binding protein

Genetic etiologies of at least 20% of autosomal dominant cerebellar ataxias (ADCAs) have yet to be clarified. We identified a novel spinocerebellar ataxia (SCA) form in four Japanese pedigrees which is caused by an abnormal CAG expansion in the TATA-binding protein (TBP) gene, a general transcription initiation factor. Consequently, it has been added to the group of polyglutamine diseases. This abnormal expansion of glutamine tracts in TBP bears 47--55 repeats, whereas the normal repeat number ranges from 29 to 42. Immunocytochemical examination of a postmortem brain which carried 48 CAG repeats detected neuronal intranuclear inclusion bodies that stained with anti-ubiquitin antibody, anti-TBP antibody and with the 1C2 antibody that recognizes specifically expanded pathological polyglutamine tracts. We therefore propose that this new disease be called SCA17 (TBP disease).

Oil components modulate physical characteristics and function of the natural oil emulsions as drug or gene delivery system

Oil-in-water (o/w) type lipid emulsions were formulated by using 18 different natural oils and egg phosphatidylcholine (egg PC) to investigate how emulsion particle size and stability change with different oils. Cottonseed, linseed and evening primrose oils formed emulsions with very large and unstable particles. Squalene, light mineral oil and jojoba bean oil formed stable emulsions with small particles. The remaining natural oils formed moderately stable emulsions. Emulsions with smaller initial particle size were more stable than those with larger particles. The correlation between emulsion size made with different oils and two physical properties of the oils was also investigated. The o/w interfacial tension and particle size of the emulsion were inversely proportional. The effect of viscosity was less pronounced. To study how the oil component in the emulsion modulates the in vitro release characteristics of lipophilic drugs, three different emulsions loaded with two different drugs were prepared. Squalene, soybean oil and linseed oil emulsions represented the most, medium and the least stable systems, respectively. For the lipophilic drugs, release was the slowest from the most stable squalene emulsion, followed by soybean oil and then by linseed oil emulsions. Cationic emulsions were also prepared with the above three different oils as gene carriers. In vitro transfection activity was the highest for the most stable squalene emulsion followed by soybean oil and then by linseed oil emulsions. Even though the in vitro transfection activity of emulsions were lower than the liposome in the absence of serum, the activity of squalene emulsion, for instance, was ca. 30 times higher than that of liposome in the presence of 80% (v/v) serum. In conclusion, the choice of oil component in o/w emulsion is important in formulating emulsion-based drug or gene delivery systems.

Optimization of lipid composition in cationic emulsion as in vitro and in vivo transfection agents

PURPOSE

To enhance in vitro and in vivo transfection activity by optimizing lipid composition of cationic lipid emulsions.

METHODS

Various emulsion formulations having different cationic lipids as emulsifiers, and additional helper lipids as co-emulsifiers, were prepared. The stability of the emulsion and its complex with DNA was investigated by measuring the particle size change in phosphate buffer saline (PBS) over a period of 20 days. The activity of the emulsions in transfecting pCMV-beta into COS-1 cells in the presence or absence of 80% serum was evaluated. We also evaluated in vivo transfection activity using intravenously administered pCMV-Luc+ as a reporter gene.

RESULTS

Among the cationic emulsifiers, 1,2-dioleoyl-sn-glycero-3-trimethylammonium-propane (DOTAP) formed the most stable and efficient emulsion gene carrier. Addition of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) increased in vitro transfection activity, but slightly compromised the stability of the emulsion. The loss was compensated for by including small amounts of Tween 80 in the emulsion. The in vitro and in vivo transfection activities were also increased by adding Tween 80. Even though in vitro transfection activity of liposomes was high in the absence of serum, the transfection activity of emulsions was far greater than that of liposomes in the presence of serum and for in vivo applications.

CONCLUSIONS

By including DOPE as an endosomolytic agent and Tween 80 as a stabilization agent, the cationic emulsion becomes a more potent gene carrier for in vitro and in vivo applications, especially in the presence of serum.

Induction of apoptosis in human leukemia cells by 3-deazaadenosine is mediated by caspase-3-like activity

3-Deazaadenosine (DZA), one of the potent inhibitors of S-adenosylhomocysteine hydrolase, is known to possess several biological properties including an induction of apoptosis. To evaluate a possibility that DZA may be utilized for the treatment of human leukemia, we studied molecular events of cell death induced by DZA in human leukemia HL-60 and U-937 cells. DZA induced a specific cleavage of poly ADP-ribose polymerase (PARP) and an activation of the cysteine protease caspase-3/CPP32 which is known to cleave PARP. DZA-mediated nuclear DNA-fragmentation was completely blocked in the presence of a universal inhibitor of caspases (z-VAD-fmk) or the specific inhibitor of caspase-3 (z-DEVD-fmk) unlike of cycloheximide (CHX). DNA fragmentation was preceded by the lowering of c-myc mRNA in the DZA treated cells. In addition, DZA-induced apoptosis was blocked by pretreatment with adenosine transporter inhibitors such as nitrobenzylthioinosine (NBTI) and dipyridamole (DPD). Taken together, these results demonstrate that DZA-induced apoptosis initiated through an active transport of DZA into human leukemia cells, is dependent on the caspase-3-like activity without de novo synthesis of proteins and possibly involves c-myc down-regulation.

Transanally injected triamcinolone acetonide in levator syndrome

PURPOSE

Several treatments are used for the treatment of levator syndrome, such as rectal massage, biofeedback, and galvanic stimulation. But their effects are inconsistent, and multiple treatment sessions are usually required. Triamcinolone acetonide and lidocaine mixture was injected locally into the tenderest point in levator syndrome under the hypothesis that levator syndrome is caused by tendinitis of pelvic floor musculature.

METHODS

A mixture of 40 mg of triamcinolone acetonide and 1 ml of 2 percent lidocaine was injected into the tenderest point transanally in 104 patients (33 males; mean age, 51 years) with levator syndrome from December 1996 to May 1998 at Daehang Clinic. Additional injections were repeated at two-week intervals to a maximum of three injections in cases of poor response. Follow-up was performed prospectively concerning patient's perception of pain level using a visual analog scale. Depending on the response, the patients were classified into four groups: pain-free, good, fair, and no response. More than 50 percent pain reduction was classified as "good," and less than 49 percent reduction as "fair."

RESULTS

The injection regions, where the tenderest points were identified on digital rectal compression, were left anterior anal canal in 71.2 percent of patients, right anterior in 3.8 percent of patients, and posterior in 25 percent of patients. The results of treatment were as follows: at three months after injection, response was classified as pain-free in 36.8 percent of patients, good in 35 percent of patients, fair in 19.5 percent of patients, and no response in 8.7 percent of patients; at six months the response was pain-free in 30.1 percent of patients, good in 46.5 percent of patients, fair in 18.2 percent of patients, and no response in 5.2 percent of patients. Most patients, except 8.7 percent at three months and 5.2 percent at six months, experienced treatment benefits. There were no complications during the follow-up periods.

CONCLUSION

Transanal injection of triamcinolone acetonide and lidocaine mixture into the tenderest point is such a simple, safe, and very effective modality that it can be recommended as a primary therapy for levator syndrome.

Germline mutations of the dpc4 gene in Korean juvenile polyposis patients

Juvenile polyposis is an uncommon condition characterized by the development of multiple (usually more than 5) juvenile polyps in the gastrointestinal tract, especially in the colon. This disease usually occurs during childhood, and is inherited in an autosomal dominant fashion. It has been suggested that the dpc4 (deleted in pancreatic carcinoma, locus 4) gene, which is located on chromosome 18q21.1, might cause juvenile polyposis. The dpc4 (smad4) gene is a candidate tumor-suppressor gene and may play a role in the TGF-beta-signaling pathway. To confirm the idea that alterations of the dpc4 gene may result in juvenile polyposis, we screened 5 Korean juvenile-polyposis patients by PCR-SSCP (single-strand conformation polymorphism) analysis and bi-directional sequencing. There were germline mutations of the dpc4 gene in 3 out of the 5 patients: 2 had a genetic alteration in exon 9 and the third had a mutation in exon 8. These germline mutations occurred in the C-terminus of the dpc4 gene, similar to most published mutations. One patient exhibited a non-sense mutation (codon 388), which changed a glutamine codon (CAG) to a stop codon (TAG). The second patient harbored a mis-sense mutation (codon 390), causing a non-conservative amino-acid change <glutamate (GAA) to lysine (AAA)>. The third patient had a mis-sense mutation in exon 8 (codon 361), which altered an arginine codon (CGC) into a histidine codon (CAC).

In vivo gene transfer to the mouse nasal cavity mucosa using a stable cationic lipid emulsion

We evaluate a new cationic emulsion as a mucosal gene carrier and elucidate the relationship between the transfection efficiency and the stability of the carrier/DNA complex. A cationic lipid emulsion was formulated with soybean oil and 1,2-dioleoyl-sn-glycero-3-trimethylammonium-propane (DOTAP) as major components and was used to transfer genes to the epithelial cells of the mouse nasal cavity via intranasal instillation. Correlation between the transfection efficiency and the stability of the carrier/DNA complex was investigated by measuring the carrier size changes and by observing the degree of DNA protection against DNase I digestion in the presence of heparin. The cationic emulsion showed at least 3 times better transfection activity than the liposomal carriers in nasal mucosae. The cationic emulsion was stable in the presence of heparin whereas the liposomal carriers became very unstable. Unlike DNA in liposome/DNA complexes, DNA in the emulsion/DNA complex was resistant to heparin exchange and DNase I digestion. The cationic emulsion was more effective in delivering DNA to nasal mucosae than commercially available liposomal carriers. The transfection activities of the lipid carriers in nasal cavity mucosae are in agreement with the stability of the lipid carriers and their complexes with DNA.

Germline mutations of the STK11 gene in Korean Peutz-Jeghers syndrome patients

Peutz-Jeghers syndrome (PJS) is an autosomal dominantly inherited disease characterized by hamartomatous gastrointestinal polyps and mucocutaneous pigmentation, with an increased risk for various neoplasms, including gastrointestinal cancer. Recently, the PJS gene encoding the serine/threonine kinase STK11 (also named LKB1) was mapped to chromosome 19p13.3, and germline mutations were identified in PJS patients. We screened a total of ten Korean PJS patients (nine sporadic cases and one familial case including two patients) to investigate the germline mutations of the STK11 gene. By polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing analysis, three kinds of mis-sense mutation and a frame-shift mutation were identified: codon 232 (TCC to CCC) in exon 5, codon 256 (GAA to GCA) in exon 6, codon 324 (CCG to CTG) in exon 8, and a guanine insertion at codon 342 resulting in a premature stop codon in exon 8. These mis-sense variants were not detected in 100 control DNA samples. Furthermore, we found an intronic mutation at the dinucleotide sequence of a splice-acceptor site: a one base substitution from AG to CG in intron 1, which may cause aberrant splicing. Most reported germline mutations of the STK11 gene in PJS patients were frame-shift or non-sense mutations resulting in truncated proteins. Together, these findings indicate that germline mis-sense mutations of the STK11 gene are found in PJS patients in addition to truncating mutations. The effects of these mutations on protein function require further examination. In summary, we found germline mutations of the STK11 gene in five out of ten Korean PJS patients.

A cationic lipid emulsion/DNA complex as a physically stable and serum-resistant gene delivery system

PURPOSE

To develop a non-viral gene delivery system in the form of an oil-in-water (o/w) lipid emulsion.

METHOD

Cationic lipid emulsions were formulated with soybean oil, 1,2-dioleoyl-sn-glycero-3-trimethylammonium-propane (DOTAP) as a cationic emulsifier and other co-emulsifiers. The physical characteristics of the lipid emulsion and the emulsion/DNA complex were determined. The in vitro transfection efficiency of the emulsion/DNA complex was determined in the presence of up to 90% serum.

RESULTS

The average droplet size and zeta potential of emulsions were ca. 180 nm and ca. +50 mV, respectively. Among the emulsions, a stable formulation was selected to form a complex with a plasmid DNA encoding chloramphenicol acetyltransferase. By increasing the ratio of emulsion to DNA. zeta-potential of the emulsion/DNA complex increased monotonously from negative to positive without any changes in the complex size. The complex was stable against DNase I digestion and an anionic poly-L-aspartic acid (PLAA). The complex delivered DNA into the cells successfully, and the transfection efficiency was not affected by complex formation time from 20 min to 2 h. More importantly, the cationic lipid emulsion facilitated the transfer of DNA in the presence of up to 90% serum.

CONCLUSIONS

The cationic lipid emulsion/DNA complex has physical stability and serum resistant properties for gene transfer.

Functional characteristics of two BKCa channel variants differentially expressed in rat brain tissues

cDNAs encoding large-conductance Ca2+-activated K+ channel alpha-subunit (rSlo) were obtained from rat brain. From the DNA sequence of multiple rslo clones, we identified a specific sequence variation of 81 nucleotides, which is either absent from or present at the N-terminal region of a putative Ca2+-sensing domain of the channel. Transcripts containing such variations were detected in different ratios from several brain regions, and their functional significance was further examined. When heterologously expressed in Xenopus oocytes, both rSlo variants, named rSlo0 and rSlo27, generated Ca2+-activated and voltage-activated K+ currents characteristic of neuronal large-conductance Ca2+-activated K+ (BKCa) channels. Single-channel recordings of the two channels showed almost identical permeation characteristics and steady-state gating behavior. Noticeable differences between rSlo0 and rSlo27 were revealed when the macroscopic currents were measured at various voltages and intracellular Ca2+ concentrations. rSlo27 activated was more rapidly than rSlo0 in the presence of the same voltage stimulus, and the differences in these activation kinetics were dependent on the concentration of intracellular Ca2+. Despite their similar apparent affinities for Ca2+, rSlo0 and rSlo27 showed significant differences in their co-operative gating behavior. The Hill coefficient for intracellular Ca2+ was estimated to be about 3.7 for rSlo27 regardless of the membrane voltage, and that for rSlo0 was reduced from about 5 to 2 as the membrane voltage changed from 40 to 140 mV. As activation of BKCa channels is involved in rapid hyperpolarization of action potentials, the differential processing of rslo transcripts, and the generation of channels with different activation kinetics and Ca2+ cooperativity may be a mechanism for tuning the excitability of neurons in different brain regions.

Identification of a novel human voltage-gated sodium channel alpha subunit gene, SCN12A

We have cloned a cDNA encoding a novel human voltage-gated sodium channel alpha subunit gene, SCN12A, from human brain. Two alternative splicing variants for SCN12A have been identified. The longest open reading frame of SCN12A encodes 1791 amino acid residues. The deduced amino acid sequence of SCN12A shows 37-73% similarity with various other mammalian sodium channels. The presence of a serine residue (S360) in the SS2 segment of domain I suggests that SCN12A is resistant to tetrodotoxin (TTX), as in the cases of rat Scn10a (rPN3/SNS) and rat Scn11a (NaN/SNS2). SCN12A is expressed predominantly in olfactory bulb, hippocampus, cerebellar cortex, spinal cord, spleen, small intestine, and placenta. Although expression level could not be determined, SCN12A is also expressed in dorsal root ganglia (DRG). Both neurons and glial cells express SCN12A. SCN12A maps to human chromosome 3p23-p21.3. These results suggest that SCN12A is a tetrodotoxin-resistant (TTX-R) sodium channel expressed in the central nervous system and nonneural tissues.

Cloning and expression study of the mouse tetrodotoxin-resistant voltage-gated sodium channel alpha subunit NaT/Scn11a

We have cloned a tetrodotoxin-resistant (TTX-R) voltage-gated sodium channel alpha subunit from a mouse cDNA library and designated it as NaT. It encodes 1765 amino acid residues and is virtually identical to that of Scn11a, which has been reported recently, except for 40 nt and 14 aa substitutions. The amino acid identity of NaT/Scn11a with rat NaN/SNS2 is 88%. NaT/Scn11a was mapped to mouse chromosome 9F3-F4 by fluorescence in situ hybridization (FISH). While rat NaN/SNS2 has been reported to be expressed specifically in the peripheral sensory neurons, NaT/Scn11a is expressed not only in the peripheral sensory neurons but also in the spinal cord, uterus, testis, ovary, placenta, and small intestine. NaT is detectable in mouse embryos 15 days postcoitus (p.c.), around the phase of organogenesis and gonadal differentiation. These findings demonstrate a unique distribution of NaT/Scn11a and suggest some of its roles in the above-mentioned processes.

Solid-state 87Rb NMR study in powdered RbMnCl3

Structural phase transition at 290 K and the implication on the intermediate phase above 290 K in powdered RbMnCl3 are observed by using a solid-state 87Rb NMR spectroscopy. Quadrupole coupling constants (e2qQ/h), the asymmetry parameters (eta), and the relative peak intensities for two physically nonequivalent Rb sites, Rb(I) and Rb(II), are determined from nonlinear least-squares fits to the 87Rb NMR powder patterns in the temperature range from 260 to 330 K. Quadrupole coupling constants and the asymmetry parameters are examined for the detection of the phase transition resulting in a significant structural change in the Rb(II) site. In addition, changes in the relative peak intensity between the Rb(I) and Rb(II) sites seem to suggest the existence of an anomalous intermediate phase, which is complemented by the differential scanning calorimetry and X-ray diffraction studies.

Peroral immunization of microencapsulated human VP8 in combination with cholera toxin induces intestinal antibody responses

To develop an orally delivered subunit vaccine for rotavirus infection, a trypsin cleavage product of VP4, recombinant VP8*, was expressed in Escherichia coli. The recombinant VP8* (rVP8*), purified by affinity chromatography, was reactive against human rotavirus positive serum in Western-blot analysis. To further evaluate the immunogenicity of the oral-delivered rVP8*, it was encapsulated with alginate-microsphere and administered in combination with cholera toxin (CT) as a mucosal adjuvant perorally into mice. The ELISPOT assay showed that the number of rVP8*-specific IgG1 antibody secreting cells increased about 3-fold and about 2-fold in spleen and Peyer's patch, respectively as compared to non-immune mice. In addition, the number of rVP8*-specific IgA antibody secreting cells increased about 2-fold in Peyer's patch. Finally, rVP8*-specific IgA antibody response was significantly enhanced in the intestinal fluids from the mice immunized perorally with encapsulated rVP8* and CT. Taken together, these results indicate that rVP8* possessed proper immunogenicity and it would be potentially useful as a subunit vaccine against rotavirus-associated disease through peroral immunization.

3-deazaadenosine, a S-adenosylhomocysteine hydrolase inhibitor, has dual effects on NF-kappaB regulation. Inhibition of NF-kappaB transcriptional activity and promotion of IkappaBalpha degradation

Previously we reported that 3-deazaadenosine (DZA), a potent inhibitor and substrate for S-adenosylhomocysteine hydrolase inhibits bacterial lipopolysaccharide-induced transcription of tumor necrosis factor-alpha and interleukin-1beta in mouse macrophage RAW 264.7 cells. In this study, we demonstrate the effects of DZA on nuclear factor-kappaB (NF-kappaB) regulation. DZA inhibits the transcriptional activity of NF-kappaB through the hindrance of p65 (Rel-A) phosphorylation without reduction of its nuclear translocation and DNA binding activity. The inhibitory effect of DZA on NF-kappaB transcriptional activity is potentiated by the addition of homocysteine. Taken together, DZA promotes the proteolytic degradation of IkappaBalpha, but not IkappaBbeta, resulting in an increase of DNA binding activity of NF-kappaB in the nucleus in the absence of its transcriptional activity in RAW 264.7 cells. The reduction of IkappaBalpha by DZA is neither involved in IkappaB kinase complex activation nor modulated by the addition of homocysteine. This study strongly suggests that DZA may be a potent drug for the treatment of diseases in which NF-kappaB plays a central pathogenic role, as well as a useful tool for studying the regulation and physiological functions of NF-kappaB.

Protective immunity of microsphere-based mucosal vaccines against lethal intranasal challenge with Streptococcus pneumoniae

Mucosal vaccination of capsular polysaccharide (PS) of Streptococcus pneumoniae and subsequent creation of the first line of immunological defense in mucosa were examined. Mucosal as well as systemic antibody responses to PS were evoked by peroral or intranasal immunization of BALB/c mice with PS-cholera toxin B subunit (CTB) conjugates entrapped in the alginate microspheres (AM). The bacterial colonization at the lung mucosa was most profoundly inhibited (<95%) by intranasal immunization with the naked conjugate (PS-CTB). The mice vaccinated orally with encapsulated conjugate [AM(PS-CTB)] showed significant reduction on the level of pneumococcal bacteremia (<99%). Eighty percent of the mice perorally immunized with AM (PS-CTB) were protected from lethal intranasal challenge with S. pneumoniae, whereas more than 60% of the mice in the other control groups died of infection. Our novel approach may prove to be important in the development of a mucosal vaccine that will provide protection of mucosal surfaces of host.

Identification of cDNAs for Sox-4, an HMG-Box protein, and a novel human homolog of yeast splicing factor SSF-1 differentially regulated during apoptosis induced by prostaglandin A2/delta12-PGJ2 in Hep3B cells

We have examined specific genes whose expression is altered during apoptosis induced by prostaglandin (PG)A2 and Delta12-PGJ2 in human hepatocellular carcinoma Hep3B cells. Using mRNA differential display, we have identified two genes: one is specifically up-regulated and encodes for human Sox-4 (Sry-HMG box gene) and the other is significantly down-regulated and is the human homolog of yeast Ssf-1, a novel splicing factor. Northern blot analysis confirmed their differential expressions. Interestingly, Sox-4 was highly expressed in subcutaneous tumors grown in nude mice as a xenograft from Hep3B cells. These results suggest that the expression of Sox-4 may be related to the apoptosis pathway leading to cell death as well as to tumorigenesis, and that Ssf-1 gene may serve as a negative regulator of PGA2/Delta12-PGJ2-mediated Hep3B cell apoptosis.