[A preliminary study on the effect of histatin 5 inhibiting Porphyromonas gingivalis and Fusobacterium nucleatum co-aggregation].

Objective: To detect the inhibitory ability of histatin 5 on the auto-aggregation of Porphyromonas gingivalis (Pg), and the co-aggregation of Pg with Fusobacterium nucleatum (Fn); and to provide a theoretical basis for the role of oral innate immunity played in the inhibition of chronic periodontitis. Methods: Saliva and supragingival, subgingival plaque samples were collected from 49 chronic periodontitis patients in School of Stomatology, China Medical University and 27 periodontal healthy individuals. Enzyme linked immunosorbent assay was used to assess the amount of histatin 5 in saliva, absolute quantitative real-time PCR (qPCR) was applied to detect the DNA copies of Fn, Pg and total bacteria in supragingival and subgingival plaque samples. The effects of histatin 5 on auto- and co-aggregation were assessed by bacterial adhesion test and scanning electron microscopy. Hemagglutinin gene, arginine-gingipains gene in Pg and FomA gene in Fn were tested by relative qPCR. Independent samples t-test was used to calculate the significance between the experimental group and the control group. P-value<0.05 was considered statistically significant. Results: For chronic periodontitis patients, there was an inverse correlation between the concentration of histatin 5 and Fn and Pg in supragingival plaque samples (r=-0.379, r=-0.624). Similarly, an inverse correlation was also observed between the concentration of histatin 5 and subgingival Fn and Pg, respectively (r=-0.404, r=-0.314). As for periodontally healthy individuals, there was an inverse correlation between the concentration of histatin 5 and supragingival and subgingival Pg (r=-0.572, r=-0.533). Bacterial adhesion test and scanning electron microscopy certified that 25 mg/L histatin 5 inhibited the auto-aggregation of Pg-Pg and the co-aggregation of Pg-Fn. Results of qPCR showed that 25 mg/L histatin 5 up-regulated hemagglutinin gene by (14.52±3.25) fold and down-regulated FomA gene to (0.22±0.10) fold. Conclusions: Histatin 5 could inhibit the auto-aggregation of Pg-Pg and the co-aggregation of Pg-Fn by regulating hemagglutinin gene and FomA gene expression.

Acquired lung cysts in post primary tuberculosis: An uncommon radiological finding in a common disease.

Tuberculosis (TB) is still an endemic disease in Malaysia. Cystic lung disease in post primary tuberculosis is not common. It can occur before, during or after completion of anti-TB treatment. Clinical history and review of serial chest radiograph is paramount to make the diagnosis. This case report highlights an interesting case of a young female patient who developed extensive cystic lung disease during the course of anti-TB treatment and the importance of recognizing this unusual manifestation.

Sensitivity of three widely used questionnaires for measuring psychological distress among patients with type 2 diabetes mellitus.

BACKGROUND: Although a range of generic and diabetes-specific instruments are available to assess emotional distress, no studies have evaluated sensitivity in relation to sample size requirement. The present study sets out to compare the sensitivity among the Diabetes Health Profile Psychological Distress scale (DHP-PD), Problem Areas in Diabetes (PAID) and Kessler-10 Psychological Distress scale (K10). We hypothesized that the diabetes-specific measures (DHP-PD and PAID) would require smaller sample sizes than the generic measure (K10), yet remain specific. RESEARCH DESIGN: A total of 208 patients with type 2 diabetes mellitus (mean age 45.2 (12.4) years; 63.1 % males, 45.8 % Chinese, 11.3 % Malay and 26.6 % Indian), recruited from a Singapore tertiary hospital diabetes clinic, completed the English DHP-PD, PAID and K10. Clinical information derived from medical records and HbA1c was recorded. Effect sizes (ES), ratio of ES and sample size requirement relative to the most sensitive questionnaire were computed. RESULTS: A comparison of patients with good versus poor glycaemic control (HbA1c ≥ 7.0) revealed that using K10 will require 4 times the sample size of a study using the PAID in order to detect the same level of psychological distress. The DHP-PD and PAID had similar sensitivity when comparing between patients with good versus poor glycaemic control. CONCLUSIONS: As hypothesized, sample size requirement is largest for K10 and remarkably similar for PAID and DHP-PD. This information is useful for designing clinical trials and studies.

Direct measurement of the percolation probability in carbon nanofiber-polyimide nanocomposites.

We present the first experimental measurement of the geometric critical exponent beta associated with the percolation probability, the probability a metallic filler belongs to the conducting network, of an electrical composite. The technique employs conducting-tip atomic force microscopy to obtain a conducting areal density, and is demonstrated on polyimide nanocomposites containing different concentrations of carbon nanofibers. We find beta approximately 1 and t (the exponent for bulk conductivity) approximately 3. These values are consistent with the predictions for the Bethe lattice and larger than the values predicted in the 3D lattice percolation model. Hence, this electrical composite likely belongs to the same universality class as the Bethe lattice. The ability to measure geometric and transport critical exponents on the same material is critical to drawing this conclusion.

Bimetallic structure fabricated by laser interference lithography for tuning surface plasmon resonance.

Tuning of surface plasmon resonance by gold and silver bimetallic thin film and bimetallic dot array is investigated. Laser interference lithography is applied to fabricate the nanostructures. A bimetallic dot structure is obtained by a lift-off procedure after gold and silver thin film deposition by an electron beam evaporator. Surface plasmon behaviors of these films and nanostructures are studied using UV-Vis spectroscopy. It is observed that for gold thin film on quartz substrate, the optical spectral peak is blue shifted when a silver thin film is coated over it. Compared to the plasmon band in single metal gold dot array, the bimetallic nanodot array shows a similar blue shift in its spectral peak. These shifts are both attributed to the interaction between gold and silver atoms. Electromagnetic interaction between gold and silver nanostructures is discussed using a simplified spring model.

The role of pH in nanofiltration of atrazine and dimethoate from aqueous solution.

This study examined the performance of nanofiltration membranes to retain atrazine and dimethoate in aqueous solution under different pH conditions. Four nanofiltration membranes, NF90, NF200, NF270 and DK are selected to be examined. The operating pressure, feed pesticide and stirring rate were kept constant at 6x10(5) Pa, 10 mg/L and 1000 rpm. It was found that increasing the solution's pH increased atrazine and dimethoate rejection but reduced the permeate flux performance for NF200, NF270 and DK. However, NF90 showed somewhat consistent performance in both rejection and permeate flux regardless of the solution's pH. NF90 maintained above 90% of atrazine rejection and approximately 80% of dimethoate rejection regardless of the changes in solution's pH. Thus, NF90 is deemed the more suitable nanofiltration membrane for atrazine and dimethoate retention from aqueous solution compared to NF200, NF270 and DK.

Dimethoate and atrazine retention from aqueous solution by nanofiltration membranes.

In order to produce sufficient food supply for the ever-increasing human population, pesticides usage is indispensable in the agriculture sector to control crop losses. However, the effect of pesticides on the environment is very complex as undesirable transfers occur continually among different environmental sections. This eventually leads to contamination of drinking water source especially for rivers located near active agriculture practices. This paper studied the application of nanofiltration membrane in the removal of dimethoate and atrazine in aqueous solution. Dimethoate was selected as the subject of study since it is being listed as one of the pesticides in guidelines for drinking water by World Health Organization. Nevertheless, data on effectiveness of dimethoate rejection using membranes has not been found so far. Meanwhile, atrazine is classified as one of the most commonly used pesticides in Malaysia. Separation was done using a small batch-type membrane separation cell with integrated magnetic stirrer while concentration of dimethoate and atrazine in aqueous solution was analyzed using high performance liquid chromatography (HPLC). Four nanofiltration membranes NF90, NF200, NF270 and DK were tested for their respective performance to separate dimethoate and atrazine. Of all four membranes, NF90 showed the best performance in retention of dimethoate and atrazine in water.

Connecting the dots: children's use of a systematic figure to facilitate mapping and search.

Organizing locations into a systematic figure was predicted to facilitate children's use of spatial relations in a mapping task. In Study 1, 3-, 4-, and 5-year-olds used a map to find a sticker hidden under 1 of 27 locations. The search locations formed a systematic figure, the outline of a dog. Half of the children were shown that the locations formed a dog. Seeing the dog pattern facilitated the performance of 5-year-olds but not that of the younger children. Study 2 indicated that children had to see a systematic figure to gain an advantage; adding lines to an unsystematic figure did not convey an advantage. Study 3 indicated that a verbal label alone could not convey an advantage. Study 4 revealed that seeing the dog pattern could also facilitate performance when the map was rotated relative to the represented space. The importance of organizing spatial information to facilitate relational thinking and mapping is discussed.

The cues that infants use to distinguish discontinuous quantities: evidence using a shift-rate recovery paradigm.

A novel experimental method, shift-rate recovery, was developed and used in a series of three experiments. These examined the extent to which 6-month-old infants (N = 131) find perceptual cues such as density and length useful in the discrimination of linearly arranged sets containing large numbers of objects. Results showed that infants discriminated between arrays that differ in number and density, with length held constant, when the arrays were presented either simultaneously or successively. On the other hand, infants discriminated only between arrays that differ in number and length, with density held constant, when the arrays were presented simultaneously. Infants were, however, able to perform a successive length discrimination when the arrays were continuous rather than consisting of discrete items. These findings support the conclusion that infants are able to discriminate between large number sets by relying on absolute cues such as density (but not length) and on relative cues such as optical one-to-one correspondence.

Effects of dietary oil contamination and absence of prophylaxis on orthodontic bonding.

The effect of contamination by dietary oil on acid etching has not been reported in the literature. If dietary oil adversely affects acid etching, then a decrease in bond strength is expected. This in vitro study investigated the bond strength of brackets bonded to tooth surfaces that had been contaminated with dietary oil and on which prophylaxis was not carried out. The mean shear bond strengths for the control, teeth with oil contamination and teeth with oil contamination but no prophylaxis undertaken were 53.33 +/- 14.31 (SD), 61.76 +/- 19.32 and 64.12 +/- 17.90 N, respectively. An analysis of variance (ANOVA) test showed that there was no significant difference between the three groups. The power of the ANOVA was calculated for the minimum clinical change that would be worth detecting and was found to be approximately 1.0. It can therefore be concluded that the presence of dietary oil on the tooth surface does not adversely affect shear bond strength, even if prophylaxis is not carried out. Bond failures for all three groups occurred mainly at the tooth-adhesive interface.

Gradient elution in micellar liquid chromatography. I. Micelle concentration gradient.

Gradient elution in micellar liquid chromatography (MLC) is discussed. On the basis of the gradient elution theory, first developed by Snyder, equations were derived for the prediction of gradient retention times in micelle concentration gradient from isocratic data. Likewise, partition coefficients into micelles and stationary phase, and subsequently isocratic retention at different micelle concentrations can be estimated from two gradient runs. However, more studies need to be done to achieve better agreement between isocratic and gradient data. The equations will be useful for efficient development of practical separations by MLC.

Gradient elution in micellar liquid chromatography. II. Organic modifier gradients.

The application of organic modifier gradients in micellar liquid chromatography (MLC) is discussed. The equation derived by Snyder and co-workers describing gradient elution in hydro-organic reversed-phase LC was verified for organic solvent gradients in the presence of micelles. It is also demonstrated that the use of these gradients require little re-equilibration time due to the limited range of organic modifier concentration used in the gradient. This would result in shorter analysis time. Lastly, a practical application of the use of propanol and acetonitrile gradients in MLC is described.

Comparative study of sultamicillin and amoxicillin-clavulanate: treatment of acute otitis media.

Sultamicillin is a mutual prodrug of ampicillin and sulbactam that is chemically linked by a diester bond. This investigational agent has beta-lactamase-inhibiting activity by virtue of sulbactam, a novel beta-lactamase inhibitor. A double blind randomized study was conducted to evaluate the safety, efficacy and tolerance of sultamicillin for treatment of acute otitis media compared with amoxicillin-clavulanate. A total of 144 subjects were included (96 randomly assigned to the sultamicillin and 48 to the amoxicillin-clavulanate groups). No safety concerns for sultamicillin were identified during the study. The clinical efficacy in effusion clearance between the two groups was found not to be statistically different at 10 days (P = 0.23) and 30 days (P = 0.72). Similar rates of side effects, primarily gastrointestinal, were reported in both study groups. Sultamicillin may be an alternative for the treatment of acute otitis media when persistence and recurrence of disease become an issue.

Liposomes as antigen vehicles to increase immunogenicity: effects of variation of structural characteristics.

Liposomes may be formulated as antigen vehicles, whose properties may be varied at will to produce structures which elicit the desired effects on the immune response against the associated antigen. Amongst the factors influencing the efficacy and nature of the adjuvant effect of liposomes are bilayer lipid composition, change and size of the vesicles, site of association of the antigen with the lipid lamellae and lipid to antigen ratio. Owing to the complex structure of these vesicles, strict control of the many differing parameters, as regards the liposome, the antigen, their positional relationship and the time of antibody assay between separate studies is difficult to achieve. The optimal conditions for adjuvant effect against a particular antigen thus need to be individualised. Further enhancement of liposomal adjuvanticity may be obtained by co-entrapment of immunomodulators such as lipid A, muramyl dipeptide and interleukin-2 and targeting to antigen-presenting cells via surface-linked sugar ligands.

A simple method for coating of liposomes with proteins.

A rapid and simple method for the coating of liposomes with proteins is described. Many proteins (e.g. bovine serum albumin, pig gammaglobulins and tetanus toxoid) could be made to adhere rapidly and efficiently to both multilamellar and small unilamellar vesicles after treatment with equimolar NaNO2 and HCl/NaCl. The reaction is complete within four hours and almost all of the protein is retained on the liposomes after storage for 2 weeks at 4 degrees C.

Targeted anti-tumor agents and their cytotoxicity on gastric cancer cells in vitro.

Several chemotherapeutic drugs including methotrexate, daunomycin, mitomycin C and toxin such as ricin, A chain of ricin were chosen to conjugate with murine monoclonal antibodies MGb2 and MG11. The drugs were linked to antibody directly or through human serum albumin as intermediary. The ELISA results showed that the antibody retained well the antigen-binding capacity during conjugation. These conjugates showed highly selective cytotoxic effect on target cells. In chronic cytotoxicity tests, the cytotoxic effect of these conjugates on human gastric cancer cells KATOIII was quite similar to that of free drugs or ricin, but greater than that of irrelevant conjugates, while they had a little effect on non-target cells, suggesting that the selective cytotoxicity on target cells of the conjugates be mediated by antibodies.

Production of monoclonal antibodies against human hepatocellular carcinoma by immunisation with a cell membrane preparation.

Monoclonal antibodies that bound to 3 human hepatocellular carcinoma cell lines (PLC/PRF/5, SK-SF and Mahlavu) and snap-frozen sections of a patient's tumour were raised by immunising mice with PLC/PRF/5 membrane preparations. The monoclonals designated RF-HCC 1 and RF-HCC 2 were of IgG1 and IgM subclasses respectively. Binding of the antibodies to surface epitopes present on Mahlavu cells in vitro took place in a biphasic fashion, with initial rapid binding of each antibody during the first 15 minutes of incubation followed by a plateau after this period. It was found that the commercially available MOPC 21 myeloma IgG1 (Sigma) monoclonal antibody used a control also bound to a surface antigenic determinant expressed on Mahlavu cells.

The prevalence of unilateral mastication in a non-patient population: a pilot study.

One hundred and twenty-seven dental undergraduates participated in a questionnaire survey containing questions relating to their experience with craniofacial pain, jaw function, oral habits and other predisposing factors. The prevalence of chronic habitual unilateral chewers (10%) in the above selected non-patient population was significantly lower than that reported in the patients suffering from craniomandibular disorders (CMD). Lateral masticatory preference was also shown to be significantly associated with symptoms such as "noises from the joints", "difficulty in opening the mouth wide", "an uncomfortable bite", "neckpains", "soreness in the teeth", "painful cheek muscles", "pain in the temples" and/or "tension in the muscles of the face and jaws". The interrelationship between unilateral mastication and CMD is discussed.