Influence of DNA characteristics on cell membrane damage stimulated by electrical short-circuiting via a low-conductive aqueous droplet in dielectric oil

We investigated gene electrotransfer using electrical short-circuiting via a cell suspension droplet in dielectric oil. An aqueous droplet of a few microliters placed between a pair of electrodes can be deformed by an intense DC electric field depending on the electric field intensity. When a droplet containing suspended cells and plasmid DNA elongates during deformation and connects the electrodes, the resulting short circuit can cause successful gene electrotransfection into various mammalian cells. We also investigated the influence of the electroporation medium on membrane permeabilization and the mechanisms of gene electrotransfection using short-circuiting via an aqueous droplet. One aim of this study was to investigate the influence of the conductivity of electroporation medium on gene electrotransfer stimulated by short-circuiting. It was found that low-conductivity medium with plasmid DNA resulted in a significant decrease in cell viability compared to the high-conductivity medium with plasmid DNA. Therefore, we demonstrated the influence of exogenous DNA on membrane damage stimulated by droplet electroporation using a low-conductivity medium. Thus, electrical stimulation with the combination of plasmid DNA and the low-conductivity medium resulted in tremendous membrane damage. Linearized plasmid DNA stimulated more significant membrane damage than circular DNA. However, the size of linear DNA did not influence the efflux of small intracellular molecules.

Influence of Electroporation Medium on Delivery of Cell-Impermeable Small Molecules by Electrical Short-Circuiting via an Aqueous Droplet in Dielectric Oil: A Comparison of Different Fluorescent Tracers

Membrane permeabilization stimulated by high-voltage electric pulses has been used to deliver cell-impermeable exogenous molecules. The electric field effect on the cells depends on various experimental parameters, such as electric field strength, the number of electric pulses, and the electroporation medium. In this study, we show the influence of the electroporation medium on membrane permeabilization stimulated by electrical short-circuiting via an aqueous droplet in dielectric oil, a novel methodology developed by our previous investigations. We investigated the membrane permeabilization by three methods, influx of calcium ions, uptake of nucleic acid-binding fluorophores (YO-PRO-1), and calcein leakage. We demonstrated that the external medium conductivity had a significant impact on the cells in all described experiments. The short-circuiting using a low-conductivity electroporation medium enhanced the formation of both transient and irreversible membrane pores. We also found that clathrin-mediated endocytosis contributed to YO-PRO-1 uptake when a cell culture medium was used as an electroporation medium.

Denosumab-related osteonecrosis of the jaw after tooth extraction and the effects of a short drug holiday in cancer patients: a multicenter retrospective study

Pre-existing inflammation, corticosteroid therapy, periapical periodontitis, longer duration of denosumab therapy, and female sex were significantly associated with an increased risk of denosumab-related osteonecrosis of the jaw after tooth extraction in patients with cancer on oncologic doses of denosumab. A short drug holiday did not protect against this complication.

INTRODUCTION

This study retrospectively investigated the relationship between various risk factors, including brief discontinuation of denosumab, and development of denosumab-related osteonecrosis of the jaw (DRONJ) after tooth extraction in patients with cancer who were receiving oncologic doses of this agent.

METHODS

Data were collected on demographic characteristics, duration of denosumab therapy, whether or not denosumab was discontinued before tooth extraction (drug holiday), duration of discontinuation, presence of pre-existing inflammation, and whether or not additional surgical procedures were performed. Risk factors for DRONJ after tooth extraction were evaluated by univariate and multivariate analyses.

RESULTS

A total of 136 dental extractions were performed in 72 patients (31 men, 41 women) with cancer who were receiving oncologic doses of denosumab. Post-extraction DRONJ was diagnosed in 39 teeth (28.7%) in 25 patients. Tooth extraction was significantly associated with development of DRONJ only in patients with pre-existing inflammation (odds ratio [OR] 243.77), those on corticosteroid therapy (OR 73.50), those with periapical periodontitis (OR 14.13), those who had been taking oncologic doses of denosumab for a longer period (OR 4.69), and in women (OR 1.04). There was no significant difference in the occurrence of DRONJ between patients who had a drug holiday before tooth extraction and those who did not.

CONCLUSIONS

These findings suggest that inflamed teeth should be extracted immediately in patients with cancer who are receiving oncologic doses of denosumab. Drug holidays have no significant impact on the risk of DRONJ.

Impact of Reactive Oxygen and Nitrogen Species Produced by Plasma on Mdm2-p53 Complex

The study of protein–protein interactions is of great interest. Several early studies focused on the murine double minute 2 (Mdm2)–tumor suppressor protein p53 interactions. However, the effect of plasma treatment on Mdm2 and p53 is still absent from the literature. This study investigated the structural changes in Mdm2, p53, and the Mdm2–p53 complex before and after possible plasma oxidation through molecular dynamic (MD) simulations. MD calculation revealed that the oxidized Mdm2 bounded or unbounded showed high flexibility that might increase the availability of tumor suppressor protein p53 in plasma-treated cells. This study provides insight into Mdm2 and p53 for a better understanding of plasma oncology.

Mechanistic studies of gene delivery into mammalian cells by electrical short-circuiting via an aqueous droplet in dielectric oil

We have developed a novel methodology for the delivery of cell-impermeable molecules, based on electrical short-circuiting via a water droplet in dielectric oil. When a cell suspension droplet is placed between a pair of electrodes with an intense DC electric field, droplet bouncing and droplet deformation, which results in an instantaneous short-circuit, can be induced, depending on the electric field strength. We have demonstrated successful transfection of various mammalian cells using the short-circuiting; however, the molecular mechanism remains to be elucidated. In this study, flow cytometric assays were performed with Jurkat cells. An aqueous droplet containing Jurkat cells and plasmids carrying fluorescent proteins was treated with droplet bouncing or short-circuiting. The short-circuiting resulted in sufficient cell viability and fluorescent protein expression after 24 hours’ incubation. In contrast, droplet bouncing did not result in successful gene transfection. Transient membrane pore formation was investigated by uptake of a cell-impermeable fluorescence dye YO-PRO-1 and the influx of calcium ions. As a result, short-circuiting increased YO-PRO-1 fluorescence intensity and intracellular calcium ion concentration, but droplet bouncing did not. We also investigated the contribution of endocytosis to the transfection. The pre-treatment of cells with endocytosis inhibitors decreased the efficiency of gene transfection in a concentration-dependent manner. Besides, the use of pH-sensitive dye conjugates indicated the formation of an acidic environment in the endosomes after the short-circuiting. Endocytosis is a possible mechanism for the intracellular delivery of exogenous DNA.

A clinical investigation of the association between perioperative oral management and prognostic nutritional index in patients with digestive and urinary cancers

Background

The prognostic nutritional index (pni) is a simple metric calculated using serum albumin and the peripheral lymphocyte count. It was reported that a low pni score is significantly associated with major postoperative complications and poor prognosis. The purpose of the present study was to investigate the effects of perioperative oral management (pom) on the perioperative pni profiles of patients with digestive system or urinary cancers.

Study Design

The medical records of 181 patients with cancer who underwent surgery and for whom a pni could be calculated were retrospectively reviewed.

Results

The intervention rate with pom was 34.8%. The median preoperative pni score was 48.25 in all patients with a pom intervention [25% to 75% interquartile range (iqr): 44.38-54.13] and 47.25 in those without an intervention (iqr: 42.0-53.5). Compared with patients not receiving pom, those who received pom had significantly higher pni scores from the early postoperative period (p < 0.05). Notably, of patients who could resume oral intake within 3 days after surgery, those who received pom intervention, compared with those who did not, had significantly higher pni scores from the early postoperative period (p < 0.05).

Conclusions

Perioperative oral management interventions might have positive effects on the postoperative pni scores of patients with cancer.

Strand breaks and chemical modification of intracellular DNA induced by cold atmospheric pressure plasma irradiation

DNA damage in the A549 human lung cancer cell line treated with cold plasma irradiation was investigated. We confirmed that cold atmospheric plasma generated reactive oxygen and nitrogen species (RONS) in a liquid, and the intracellular RONS level was increased in plasma-irradiated cells. However, a notable decrease in cell viability was not observed 24 hours after plasma irradiation. Because RONS induce oxidative damage in cells, strand breaks and chemical modification of DNA in the cancer cells were investigated. We found that 8-oxoguanine (8-oxoG) formation as well as DNA strand breaks, which have been thoroughly investigated, were induced by plasma irradiation. In addition, up-regulation of 8-oxoG repair enzyme was observed after plasma irradiation.

Introduction of a plasmid and a protein into bovine and swine cells by water-in-oil droplet electroporation

Instrument cost is a major problem for the transduction of DNA fragments and proteins into cells. Water-in-oil droplet electroporation (droplet-EP) was recently invented as a low-cost and effective method for the transfection of plasmids into cultured human cells. We here applied droplet-EP to livestock animal cells. Although it is difficult to transfect plasmids into bovine fibroblasts using conventional lipofection methods, droplet-EP enabled us to introduce an enhanced green fluorescent protein (EGFP)-expressing plasmid into bovine earlobe fibroblasts. The optimal transfection condition was 3.0 kV, which allowed 19.1% of the cells to be transfected. For swine earlobe fibroblasts, the maximum transfection efficacy was 14.0% at 4.0 kV. After transfection with droplet-EP, 69.1% of bovine and 76.5% of swine cells were viable. Furthermore, droplet-EP successfully transduced Escherichia coli recombinant EGFP into frozen-thawed bovine sperm at 1.5 kV. Flow cytometry analysis revealed that 71.5% of spermatozoa exhibited green fluorescence after transfection. Overall, droplet-EP is suitable for the transfection of plasmids and proteins into cultured livestock animal cells.

Effectiveness of a comprehensive oral management protocol for the prevention of severe oral mucositis in patients receiving radiotherapy with or without chemotherapy for oral cancer: a multicentre, phase II, randomized controlled trial

The aim of this phase II, multicentre, randomized controlled trial was to evaluate the effectiveness of a comprehensive oral management protocol for the prevention of severe oral mucositis in patients with oral cancer receiving radiotherapy alone or chemoradiotherapy. In total, 124 patients with oral cancer were enrolled from five institutions. Of these, 37 patients undergoing radiotherapy were randomly divided into an intervention group (n=18) and a control group (n=19). The remaining 87 patients, who were undergoing chemoradiotherapy, were also randomized into an intervention group (n=42) and a control group (n=45). During radiotherapy, patients in the control group received only oral care, while those in the intervention group additionally received spacers to cover the entire dentition, pilocarpine hydrochloride, and topical dexamethasone ointment for oral mucositis. The primary endpoint was the incidence of severe oral mucositis. The intervention was significantly associated with a decreased incidence of severe oral mucositis in patients receiving radiotherapy alone (P=0.046), but not in those receiving chemoradiotherapy (P=0.815). These findings suggest that an oral management protocol can prevent severe oral mucositis in patients with oral cancer undergoing radiotherapy without concurrent chemotherapy.

Medication-related osteonecrosis of the jaw after tooth extraction in cancer patients: a multicenter retrospective study

Root amputation, immunosuppressive therapy, mandibular tooth extraction, pre-existing inflammation, and longer duration of treatment with bone-modifying agents were significantly associated with an increased risk of medication-related osteonecrosis of the jaw. Hopeless teeth should be extracted without drug holiday before the development of inflammation in cancer patients receiving high-dose bone-modifying agents.

INTRODUCTION

No studies have comprehensively analyzed the influence of pre-existing inflammation, surgical procedure-related factors such as primary wound closure, demographic factors, and drug holiday on the incidence of medication-related osteonecrosis of the jaw (MRONJ). The purpose of this study was to retrospectively investigate the relationships between these various factors and the development of MRONJ after tooth extraction in cancer patients receiving high-dose bone-modifying agents (BMAs) such as bisphosphonates or denosumab.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated with univariate and multivariate analyses. The following parameters were investigated in all patients: demographics, type and duration of BMA use, whether BMA use was discontinued before tooth extraction (drug holiday), the duration of such discontinuation, the presence of pre-existing inflammation, and whether additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 22.62), immunosuppressive therapy (OR = 16.61), extraction of mandibular teeth (OR = 12.14), extraction of teeth with pre-existing inflammation, and longer duration (≥ 8 months) of high-dose BMA (OR = 7.85) were all significantly associated with MRONJ.

CONCLUSIONS

Tooth extraction should not necessarily be postponed in cancer patients receiving high-dose BMA. The effectiveness of a short-term drug holiday was not confirmed, as drug holidays had no significant impact on MRONJ incidence. Tooth extraction may be acceptable during high-dose BMA therapy until 8 months after initiation.

A multicenter retrospective study of the risk factors associated with medication-related osteonecrosis of the jaw after tooth extraction in patients receiving oral bisphosphonate therapy: can primary wound closure and a drug holiday really prevent MRONJ?

Root amputation, extraction of a single tooth, bone loss or severe tooth mobility, and an unclosed wound were significantly associated with increased risk of developing medication-related osteonecrosis of the jaw (MRONJ). We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates.

INTRODUCTION

Osteonecrosis of the jaws can occur following tooth extraction in patients receiving bisphosphonate drugs. Various strategies for minimizing the risk of MRONJ have been advanced, but no studies have comprehensively analyzed the efficacy of factors such as primary wound closure, demographics, and drug holidays in reducing its incidence. The purpose of this study was to retrospectively investigate the relationships between these various risk factors after tooth extraction in patients receiving oral bisphosphonate therapy.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated using univariate and multivariate analysis. All patients were investigated with regard to demographics; type and duration of oral bisphosphonate use; whether they underwent a discontinuation of oral bisphosphonates before tooth extraction (drug holiday), and the duration of such discontinuation; and whether any additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 6.64), extraction of a single tooth (OR = 3.70), bone loss or severe tooth mobility (OR = 3.60), and an unclosed wound (OR = 2.51) were significantly associated with increased risk of developing MRONJ.

CONCLUSIONS

We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates. We find no evidence supporting the efficacy of a pre-extraction short-term drug holiday from oral bisphosphonates in reducing the risk of MRONJ.

Natriuretic peptide receptor A is related to the expression of vascular endothelial growth factors A and C, and is associated with the invasion potential of tongue squamous cell carcinoma

Natriuretic peptide receptor A (NPRA) is one of the natriuretic peptide receptors. NPRA has been reported to play a role in the carcinogenesis of various tumours, as well as functional roles in renal, cardiovascular, endocrine, and skeletal homeostasis. The clinicopathological significance of NPRA in tongue squamous cell carcinoma (TSCC) was examined in this study. The overexpression of NPRA was more frequent in TSCC (21/58, 36.2%) than in the normal oral epithelium (0/10, 0%) (P<0.05). It was also more frequently observed in cancers with higher grades according to the pattern of invasion (grades 1-2 vs. grades 3-4, P<0.01). Additionally, there was a tendency towards an association between the N classification and NPRA expression (N0 vs. N1-2, P=0.06). Significant correlations were also observed between the expression of NPRA and that of VEGF-A (P<0.001) and VEGF-C (P<0.001). The high-NPRA expression group had a significantly poorer prognosis, with a 5-year disease-specific survival rate of 39.7%, compared to 97.0% in the low-expression group (P<0.001). Multivariate analysis suggested that the overexpression of NPRA may also be an independent prognostic factor (P<0.05). In conclusion, NPRA is associated with VEGF expression levels, invasion, and metastasis, and may be a prognostic factor in TSCC patients.

Direct single-molecule observations of DNA unwinding by SV40 large tumor antigen under a negative DNA supercoil state

Superhelices, which are induced by the twisting and coiling of double-helical DNA in chromosomes, are thought to affect transcription, replication, and other DNA metabolic processes. In this study, we report the effects of negative supercoiling on the unwinding activity of simian virus 40 large tumor antigen (SV40 TAg) at a single-molecular level. The supercoiling density of linear DNA templates was controlled using magnetic tweezers and monitored using a fluorescent microscope in a flow cell. SV40 TAg-mediated DNA unwinding under relaxed and negative supercoil states was analyzed by the direct observation of both single- and double-stranded regions of single DNA molecules. Increased negative superhelicity stimulated SV40 TAg-mediated DNA unwinding more strongly than a relaxed state; furthermore, negative superhelicity was associated with an increased probability of SV40 TAg-mediated DNA unwinding. These results suggest that negative superhelicity helps to regulate the initiation of DNA replication.

Fundamental study on a gene transfection methodology for mammalian cells using water-in-oil droplet deformation in a DC electric field

We have developed a gene transfection method called water-in-oil droplet electroporation (EP) that uses a dielectric oil and a liquid droplet containing live cells and exogenous DNA. When a cell suspension droplet is placed between a pair of electrodes, an intense DC electric field can induce droplet deformation, resulting in an instantaneous short circuit caused by the droplet elongating and contacting the two electrodes simultaneously. Small transient pores are generated in the cell membrane during the short, allowing the introduction of exogenous DNA into the cells. The droplet EP was characterized by varying the following experimental parameters: applied voltage, number of short circuits, type of medium (electric conductivity), concentration of exogenous DNA, and size of the droplet. In addition, the formation of transient pores in the cell membrane during droplet EP and the transfection efficiency were evaluated.

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Characterization of water-in-oil droplet electroporation.

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The electric field strength is the most critical experimental parameter.

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The volume of the droplet affects viability and gene expression.

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Droplet deformation under a DC electric field is critical.

Nutritional and Mental Health Status of Afghan Refugee Children in Peshawar, Pakistan: A Descriptive Study

The study sought to ascertain and describe the physical and mental health states of Afghan refugee children after the terrorist attack on September 11, 2001 in the US and the aerial bombing of Afghanistan that followed. A cross-sectional survey was carried out in four refugee camps in Peshawar, Pakistan from February to March 2002, and comparisons among camps were made. A total of 70 males (mean age SD = 9.81 ±1.98 years old) and 30 females (7.94 ±2.07) answered a self-developed questionnaire on demographic data, traumatic events experience, living environment in the camps, and physical and mental health, through interviews. Anthropometric measures were measured and physical symptoms including anaemia and edema were assessed. Severe malnutrition was not shown and there were no significant differences in most nutritional and physical states among the camps. Nevertheless, in the newer camps more children experienced war related traumatic events. Mental symptoms were prevalent in all camps, though the characteristics of the symptoms differed among the camps. Asia Pac J Public Health 2005; 17(2): 93-98.

Modified Cyclodextrin Sulphates(mCDS11) have Potent Inhibitory Activity against HIV and High Oral Bioavailability

Modified cyclodextrin sulphate (mCDS) in which lipophilic groups were introduced to cyclodextrin sulphate (CDS) was synthesized and proved more inhibitory to the replication of HIV-1 and HIV-2 than CDS or dextran sulphate (DS). The anti-coagulant activity of mCDS was lower than that of DS. Cyclodextrin phosphate (CDP) showed anti-HIV activity similar to that of CDS, and its anti-coagulant activity was even lower than that of mCDS. Flow cytometric analysis suggested that the mechanism of the anti-HIV-1 action of CDS, mCDS, and CDP is based on inhibition of HIV-1 binding to the cells. The peak blood concentration after oral administration of mCDS11(potassium tris[6-benzylthio-6-deoxy]-β-cyclodextrin hexadecasulphate) to rabbits was about 1000 times higher than the concentration showing anti-HIV activity. The retention time in the blood was also long (blood half-life: 4 h). These results point to the potential usefulness of oral mCDS administration in the prophylaxis and/or therapy of HIV infections.

Direct single-molecule observations of local denaturation of a DNA double helix under a negative supercoil state

Effects of a negative supercoil on the local denaturation of the DNA double helix were studied at the single-molecule level. The local denaturation in λDNA and λDNA containing the SV40 origin of DNA replication (SV40ori-λDNA) was directly observed by staining single-stranded DNA regions with a fusion protein comprising the ssDNA binding domain of a 70-kDa subunit of replication protein A and an enhanced yellow fluorescent protein (RPA-YFP) followed by staining the double-stranded DNA regions with YOYO-1. The local denaturation of λDNA and SV40ori-λDNA under a negative supercoil state was observed as single bright spots at the single-stranded regions. When negative supercoil densities were gradually increased to 0, -0.045, and -0.095 for λDNA and 0, -0.047, and -0.1 for SV40ori-λDNA, single bright spots at the single-stranded regions were frequently induced under higher negative supercoil densities of -0.095 for λDNA and -0.1 for SV40ori-λDNA. However, single bright spots of the single-stranded regions were rarely observed below a negative supercoil density of -0.045 and -0.047 for λDNA and SV40ori-λDNA, respectively. The probability of occurrence of the local denaturation increased with negative superhelicity for both λDNA and SV40ori-λDNA.

Real-time single-molecule observations of T7 Exonuclease activity in a microflow channel

T7 Exonuclease (T7 Exo) DNA digestion reactions were studied using direct single-molecule observations in microflow channels. DNA digestion reactions were directly observed by staining template DNA double-stranded regions with SYTOX Orange and staining single-stranded (digested) regions with a fluorescently labeled ssDNA-recognizing peptide (ssBP-488). Sequentially acquired photographs demonstrated that a double-stranded region monotonously shortened as a single-stranded region monotonously increased from the free end during a DNA digestion reaction. Furthermore, DNA digestion reactions were directly observed both under pulse-chase conditions and under continuous buffer flow conditions with T7 Exo. Under pulse-chase conditions, the double-stranded regions of λDNA monotonously shortened by a DNA digestion reaction with a single T7 Exo molecule, with an estimated average DNA digestion rate of 5.7 bases/s and a processivity of 6692 bases. Under continuous buffer flow conditions with T7 Exo, some pauses were observed during a DNA digestion reaction and double-stranded regions shortened linearly except during these pauses. The average DNA digestion rate was estimated to be 5.3 bases/s with a processivity of 5072 bases. Thus, the use of our direct single-molecule observations using a fluorescently labeled ssDNA-recognizing peptide (ssBP-488) was an effective analytic method for investigating DNA metabolic processes.

Gender differences in serum testosterone and cortisol in patients with major depressive disorder compared with controls

OBJECTIVE

Testosterone may have a role distinct from cortisol in the pathophysiology of depression. The hypothalamus-pituitary-adrenal (HPA) axis affects the functions of sex steroid hormones through interaction with corticotropin-releasing hormone (CRH) and gonadotropin-releasing hormone (GnRH). The objective of this study was to investigate differences in serum levels of testosterone and cortisol in male and female patients with major depressive disorder (MDD).

METHODS

Participants included 87 inpatients with MDD at Juntendo University Koshigaya Hospital. Serum levels of testosterone and cortisol were assessed at admission. Matched controls included 128 healthy individuals. Data from MDD patients and controls were compared separately for men and women. Correlations between serum hormone levels and scores on the Hamilton Rating Scale for Depression (HAM-D) of patients were assessed by sex. Effects of various factors on testosterone and cortisol were analyzed using multiple regression analysis.

RESULTS

In male patients with MDD, a significant negative correlation was seen between testosterone levels and the "retardation" score of HAM-D. However, serum testosterone levels were not significantly different in either male or female MDD patients compared with controls. Serum testosterone was negatively associated with the number of depressive episodes in male patients with MDD. Serum cortisol levels in female patients were significantly increased compared with female controls with no significant correlations between cortisol levels and HAM-D scores.

CONCLUSIONS

The negative correlation between the sub-score of the HAM-D and testosterone may be associated with the biological pathophysiology of male depression. Findings of serum cortisol levels in women may suggest distinct characteristics of these hormones in men and women with MDD.

A new direct single-molecule observation method for DNA synthesis reaction using fluorescent replication protein A

Using a single-stranded region tracing system, single-molecule DNA synthesis reactions were directly observed in microflow channels. The direct single-molecule observations of DNA synthesis were labeled with a fusion protein consisting of the ssDNA-binding domain of a 70-kDa subunit of replication protein A and enhanced yellow fluorescent protein (RPA-YFP). Our method was suitable for measurement of DNA synthesis reaction rates with control of the ssλDNA form as stretched ssλDNA (+flow) and random coiled ssλDNA (−flow) via buffer flow. Sequentially captured photographs demonstrated that the synthesized region of an ssλDNA molecule monotonously increased with the reaction time. The DNA synthesis reaction rate of random coiled ssλDNA (−flow) was nearly the same as that measured in a previous ensemble molecule experiment (52 vs. 50 bases/s). This suggested that the random coiled form of DNA (−flow) reflected the DNA form in the bulk experiment in the case of DNA synthesis reactions. In addition, the DNA synthesis reaction rate of stretched ssλDNA (+flow) was approximately 75% higher than that of random coiled ssλDNA (−flow) (91 vs. 52 bases/s). The DNA synthesis reaction rate of the Klenow fragment (3′-5′exo–) was promoted by DNA stretching with buffer flow.

Note: practical monitoring system using characteristic impedance measurement during plasma processing

A method for characteristic impedance monitoring (CIM) is developed for anomaly detection during plasma processing. Advantages of the method include high-sensitivity and real-time monitoring, as well as structural simplicity to install the measurement system in the mass production equipment. To obtain real-time monitoring without time delay, our CIM system consists of a directional coupler and a newly developed vector processing system instead of the conventional high voltage and current probes. The system can measure the time variations of characteristic and load impedances even while the plasma is generated.

Auditory findings after stereotactic radiosurgery in acoustic neurinoma

Auditory function after gamma knife stereotactic radiosurgery (GK) was evaluated in 22 patients with newly diagnosed unilateral acoustic neurinoma who had had some measurable hearing preoperatively. No tumor growth was observed in any patients. The preservation rates for useful hearing (n = 13) and any measurable hearing (n = 22) were 62% and 86%, respectively, at 2 years after GK. Postoperative hearing dysfunction was attributed to progressive cochlear impairment in 13 patients and to progressive injury in the retrocochlear auditory pathway in 5 patients. Hearing tended to be well preserved when caloric response was unchanged postoperatively. Preservation of hearing was not associated with the initial tumor volume, decrease of tumor size, maximum tumor dose, or peripheral tumor dose.

The effect of physical form of DNA on exonucleaseIII activity revealed by single-molecule observations

Single-molecule studies have revealed molecular behaviors usually hidden in the ensemble and time averaging of bulk experiments. Single-molecule measurement that can control physical form of individual DNA molecules is a powerful method to obtain new knowledge about correlation between DNA-tension and enzyme activity. Here we study the effect of physical form of DNA on exonucleaseIII (ExoIII) reaction. ExoIII has a double-stranded DNA specific 3'-->5' exonuclease activity and the digestion is distributive. We observed the ExoIII digestion of individual stretched DNA molecules from the free ends. The sequentially captured photographs demonstrated that the digested DNA molecule linearly shortened with the reaction time. We also carried out the single-molecule observation under random coiled form by pausing the buffer flow. The digestion rates obtained from both single-molecule experiments showed that the digestion rate under the stretched condition was two times higher than the random coiled condition. The correlation between physical form of DNA and digestion rate of ExoIII was clearly demonstrated by single-molecule observations.

Baseline clinical and radiographic features are associated with long-term (8 years) signs/symptoms for subjects with diseased temporomandibular joint

OBJECTIVES

The purpose of this study was to determine the extent to which baseline clinical and radiographic features were associated with long-term outcomes in patients with temporomandibular joint disorder (TMJD).

METHODS

49 patients with unilateral radiographically proven TMJD were available in this study. Self-reported long-term (mean 96.2 months) outcomes (current joint pain, maximum mouth opening and joint noise) after TMJD treatments were assessed by questionnaire. The impact of multiple initial clinical/radiographic findings (gender, age at first visit, time interval between first visit and questionnaire survey, treatment method, disc displacement, disc morphology, disc mobility, condylar bony change and morphology of the articular eminence) on the long-term outcomes was assessed using stepwise multiple regression and logistic regression analysis.

RESULTS

Patient age at the first visit was significantly correlated with current joint pain. Disc mobility and morphology of the articular eminence were significantly correlated with current range of maximal mouth opening.

CONCLUSIONS

The results of this study suggest that patients who appeared symptomatic at a younger age or who initially had a fixed disc were the most likely to have recurrent or persisting clinical signs/symptoms of TMJD after 8 years.

Young adult-specific hyperphagia in diabetic Goto-kakizaki rats is associated with leptin resistance and elevation of neuropeptide Y mRNA in the arcuate nucleus

The present study aimed to examine whether hyperphagia, which is frequently observed in type 1 diabetic patients and model animals, also occurs in type 2 diabetic Goto-Kakizaki (GK) rats and, if so, to explore underlying abnormalities in the hypothalamus. GK rats at postnatal weeks 6-12, compared to control Wistar rats, exhibited hyperphagia, hyperglycaemia, hyperleptinemia and increased visceral fat accumulation, whereas body weight was unaltered. The ability of leptin to suppress feeding was reduced in GK rats compared to Wistar rats of these ages. In GK rats, leptin-induced phosphorylation of signal transducer and activator of transcription 3 was significantly reduced in the cells of the hypothalamic arcuate nucleus (ARC), but not of the ventromedial hypothalamus, whereas the mRNA level of functional leptin receptor was unaltered. By real-time polymerase chain reaction and in situ hybridisation, mRNA levels of neuropeptide Y, but not pro-opiomelanocortin and galanin-like peptide, were significantly increased in the ARC of GK rats at 11 weeks, but not 26 weeks. Following i.c.v. injection of a NPY Y1 antagonist, 1229U91, the amount of food intake in GK rats was indistinguishable from that in Wistar rats, thus eliminating the hyperphagia of GK rats. These results demonstrate that young adult GK rats display hyperphagia in association with leptin resistance and increased NPY mRNA level in the ARC.

Nosocomial transmission of methicillin-resistant Staphylococcus aureus via the surfaces of the dental operatory

OBJECTIVE

We assess the possibility of methicillin-resistant Staphylococcus aureus (MRSA) transmission via the surfaces of the dental operatory.

METHODS

A survey of MRSA contamination on the surfaces of the dental operatory, and an analysis of MRSA transmission via the dental operatory between patients was carried out in the department of special dental care and oral surgery.

RESULTS

MRSA was observed on the surfaces of dental operatory including the air-water syringe and reclining chair. Nosocomial infection or colonisation of MRSA occurred in eight out of 140 consecutive patients who had no evidence of MRSA at admission. Antibiograms of 30 antibiotics revealed that the isolates from the eight patients were of the same strain as those from the surface of dental operatory. After treating the patients under a revised infection control (IC) protocol including a single use of barrier covers, MRSA was not detected on the surfaces of the dental operatory, and no nosocomial infection or colonisation occurred during hospitalisation (0/117 patients).

CONCLUSIONS

These results suggest that MRSA contaminates the surfaces of the dental operatory, and therefore the dental operatory should be considered a possible reservoir of MRSA.

A long-term follow-up study of radiographically evident degenerative changes in the temporomandibular joint with different conditions of disk displacement

The purpose of this retrospective study is to assess the relationship between an initial and persisting condition of disk displacement (DD) and the long-term course of radiographically evident degenerative changes of the temporomandibular joint (TMJ). Nineteen patients agreed to a radiographic follow-up examination of 29 joints and were included in this study. The joints were radiographically assessed at the first visit and at least 46 months after the first visit (mean 89.3 months). At the time of the follow-up, all subjects had a good clinical course after a favorable response to the treatments. There were significant relationships between the initial diagnosis of DD and the interval change in the morphology of the articular eminence. The articular eminence became flattened or deformed only in the joints with persistent DD without reduction. And there was a tendency that the condyle became smaller in the joints initially with permanent DD and in the joints which show a progression in the disk-condylar relationship. The results of this study suggested that, in the joints with persisting non-reducing disk displacement, flattening and deformation of the articular eminence and regression of the condylar size were likely to happen even after symptoms and signs of TMJ disorders were resolved or reduced.

Recovery of intact yeast chromosomal DNA from agarose gel plugs using coil-globule transition

In the current studies, we designed a new approach for sizing and isolating chromosomal DNA using coil-globule transition, which avoids fragmentation of giant DNA due to mechanical stress. Although coil-globule transition is reversible and globular DNA is tolerant to mechanical stress, globular DNA cannot be manipulated by an electric field because of the loss of its negative charges. In our system, however, DNA is extracted from an agarose gel in a coiled state into a solution of PEG, and coil-globule transition is induced by cations generated at the anode. This method achieves buffer exchange without stirring, which is the main cause of mechanical stress. Real-time analysis of T4dc viral DNA molecules revealed that they change immediately from a coiled to a globular form when the cation concentration is sufficiently high. This method was used to prepare yeast chromosomal DNA in a globular state without fragmentation.

Adaptor polymerase chain reaction for single molecule amplification

The adaptor polymerase chain reaction (PCR) permits the amplification of DNA fragments with arbitrary sequences. In this paper, we describe the successful amplification of plasmid-derived single molecule DNAs digested by a restriction enzyme. By using adaptors made of short and long oligonucleotides, nonspecific interactions during PCR were suppressed. The method will be applicable to the detection of single molecule DNA fragments even if their sequence is unknown.

Single-molecule reverse transcription polymerase chain reaction using water-in-oil emulsion

A new method based on a combination of reverse transcription polymerase chain reaction (RT-PCR) and a water-in-oil (W/O) emulsion was developed. Reverse transcription and initial thermal cycles were carried out in droplets of the W/O emulsion. Then, the droplets were united, followed by remaining secondary PCR cycles. This two-step method succeeded in detecting a single RNA molecule.