Prognostic relevance of topoisomerase II α and minichromosome maintenance protein 6 expression in colorectal cancer.

BACKGROUND: Despite rising incidence rates of colorectal malignancies, only a few prognostic tools have been implemented in proven clinical routine. Cell division and proliferation play a significant role in malignancies. In terms of colorectal cancer, the impact of proliferation associated proteins is controversially debated. The aim of our study was to examine the expression of topoisomerase II α and minichromosome maintenance protein 6 and to correlate these findings with the clinical data. METHODS: Tissue samples of 619 patients in total were stained using the antibodies Ki-S4 and Ki-MCM6 targeting topoisomerase II α as well as minichromosome maintenance protein 6. The median rate of proliferation was correlated with clinical and follow up data. RESULTS: The expression rate of minichromosome maintenance protein 6 is significantly higher than the proportion of topoisomerase II α in tumour cells (p < 0.001). A high expression of both proteins coincides with a beneficial outcome for the patient, indicating a favourable prognostic marker (p < 0.001 and p = 0.008). CONCLUSIONS: We have demonstrated that high expression rates of proliferative markers is linked to a beneficial patient outcome. According to the general opinion, a high expression rate correlates with a poor patient outcome. In this study, we were able to refute this assertion.

Polymethacrylate based microparticulates of insulin for oral delivery, part II: solid state characterization.

The objectives of the present study were (A) to characterize insulin microparticles prepared by the coprecipitation process by size exclusion chromatography, differential scanning calorimetry, fourier-transform IR spectroscopy, and powder X-ray diffractometry, and (B) to study the solid state conformation of insulin before and after entrapment in the polymeric carrier. Microparticles were prepared by dissolving insulin in 0.01 N HCI and alcohol USP to get a final concentration of 32% v/v. Eudragit L100, a representative polymethyacrylate polymer, was then dissolved in this solution which was transferred to a beaker containing cold water with homogenization to obtain microparticulates. Insulin powder, microcapsules, and a physical mixture of insulin and Eudragit L100 were then analyzed by SEC-HPLC, DSC, FTIR, and XRD to observe changes in protein conformation as result of the manufacturing process. While DSC, XRD and FTIR results were of limited value due to limits of instrument sensitivity, size exclusion chromatography data indicated that higher order aggregates were not formed during microcapsule formation. It was concluded that formulating insulin into microparticles by the coprecipitation process is an attractive and stable method for protein delivery and might be suitable for oral delivery of insulin.

In vitro phonophoresis: effect of ultrasound intensity and mode at high frequency on NSAIDs transport across cellulose and rabbit skin membranes.

The objective of this study was to evaluate the effect of intensity, mode, and duration of ultrasound application on the transport of three nonsteroidal anti-inflammatory drugs (NSAIDs) across cellulose membrane and rabbit-skin. Ibuprofen, piroxicam and diclofenac sodium were used as the model drugs. Studies were performed in vitro using a modified Franz diffusion assembly adapted to a therapeutic ultrasound transducer. Ultrasound had a significant and positive effect on the transport of the model NSAIDs across cellulose and rabbit skin membranes. Increasing ultrasound intensity from 0.5 to 3.0 W/cm2 led to a proportional increase in drug transport. Continuous ultrasound mode was more effective in enhancing drug transport than the pulsed mode. Diclofenac sodium had the least flux and permeability coefficient. This was attributed to its comparatively lower pKa value that renders the drug more ionizable in the buffer solution, consequently reducing its selective penetration through the membranes. This study demonstrated the therapeutic potential of ultrasound in transdermal delivery of NSAIDs and the synergistic effect of temperature and ultrasound operational parameters on drug transport.

Ex vivo mucoadhesion and in vivo bioavailability assessment and correlation of ketoprofen tablet dosage forms containing bioadhesives.

The purposes of this study were to assess the mucoadhesion and bioavailability and their correlation for ketoprofen tablet dosage forms (F1-F6) containing polycarbophil (PC), sodium carboxymethylcellulose (Na CMC) as bioadhesives, Avicel pH 101 as direct compressible tablet vehicle or mixtures of these, and non compressible vehicles such as lactose and starch. For mucoadhesion assessment, we used sheep gastric mucosa and for bioavailability we used six human volunteers in an open randomized seven-way crossover study. Young's modulus (YM) and relative bioavailability (RB) parameters were used for evaluation of mucoadhesion and bioavailability, respectively. The results indicated that F2 containing Na CMC (72.5%) showed the highest value of YM (7.6 +/- 0.76 pascals) and 119.4 +/- 3.2% for RB. Decreasing the amount of Na CMC to 10% in F3 and F6 decreased the values of YM and RB to 1.4 +/- 0.08 and 84 +/- 2.05 in F3, 4.6 +/- 0.43 and 114.7 +/- 2.46 in F6, respectively. The highest RB (152.3 +/- 2.56) was observed in F5 containing starch and Avicel pH 101. This formulation showed 6 +/- 0.87 for YM. F4 containing PC (10%) showed 5.1 +/- 0.43 and 74.15 +/- 1.98 for YM and RB respectively. The lowest value of YM was observed in F1 containing Avicel pH 101 (0.27 +/- 0.01) which also showed low RB (93.3 +/- 2.3). In conclusion, formulations containing bioadhesives and/or starch in high concentration showed high values of YM and RB which indicate good correlation between mucoadhesion and bioavailability. Bioadhesives may show a high potential to improve bioavailability and therapeutic efficacy of ketoprofen in tablet dosage forms.

Optimization of a self-nanoemulsified tablet dosage form of Ubiquinone using response surface methodology: effect of formulation ingredients.

The objectives of the present study were (1) to evaluate the effect of formulation ingredients on the release rate of Ubiquinone from its adsorbing solid compact; and (2) to prepare and evaluate an optimized self-nanoemulsified tablet formulation. A three factor, three-level Box-Behnken design was used for the optimization procedure, with the amounts of copolyvidone (X(1)), maltodextrin (X(2)) and microcrystalline cellulose (X(3)) as the independent variables. The response variable was cumulative percent of Ubiquinone emulsified in 45 min with constraints on weight, flowability index, tensile strength, friability and disintegration time of the dry powdered emulsion and the resultant compact. Based on the experimental design, different Ubiquinone release rates and profiles were obtained. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The regression equation generated for the cumulative percent emulsified in 45 min was Y(6)=64.10-12.32X(1)-4.36X(2)-25.53X(3)+6.99X(1)X(2)+3.97X(1)X(3)+9.70X(2)X(3)-8.98X(1)(2)16.22X(2)(2)+17.10X(3)(2). The optimization model predicted an 85.4% release with X(1), X(2) and X(3) levels of 66.6, 560.1 and 100, respectively. A new formulation was prepared according to these levels. The observed responses were in close agreement with the predicted values of the optimized formulation.

Preparation and in vitro characterization of a eutectic based semisolid self-nanoemulsified drug delivery system (SNEDDS) of ubiquinone: mechanism and progress of emulsion formation.

The objectives of the present work were, first, to develop a self-nanoemulsified drug delivery system (SNEDDS) based on the eutectic properties of ubiquinone (CoQ10); and second, to study the progress of emulsion formation and drug release mechanisms by turbidimetry and droplet size analysis. Binary phase diagrams of CoQ10 with menthol and essential oils were constructed and used to develop the self-nanoemulsified formulation. Pseudo ternary phase diagram was constructed to identify the efficient self-emulsification region. Release mechanisms of the resultant formulas were quantified using turbidimetry in combination with dissolution studies. Turbidity time profiles revealed three distinctive regions: lag phase, plateau, and the pseudolinear phase. Lag phase was attributed to the liquid crystalline properties of the formula. Plateau turbidity was correlated with droplet size. Laser diffraction analysis revealed an average droplet diameter of 100 nm. Emulsification rate was obtained from the corrected slope of the pseudolinear phase of the profile. Stability of the formula was further evaluated using Fourier transform-infrared (FT-IR) attached to an attenuated total reflectance (ATR) accessory. The present study revealed a eutectic based semisolid self-emulsified delivery system that can overcome the drawbacks of the traditional emulsified systems such as low solubility and irreversible precipitation of the active drug in the vehicle with time.

Characterization of soft gelatin capsules by thermal analysis.

Thermal analysis of soft gelatin capsule was used as a diagnostic tool to evaluate the effect of temperature and humidity stress conditions as well as formulation water, propylene glycol and ethanol on the softening of the gelatin shells. Results obtained using modulated and conventional DSC given as DeltaT(m) (change in gel-sol transition temperature) were compared with the results obtained using manual hardness tester given as % hardness loss. No difference between the two methods was observed in their ability to determine the extent of softening due to formulation water, propylene glycol and ethanol content. Thermal analysis and shifts in the reversible heat flow determined using MDSC provided additional insight into the structural changes and extent of deformation within the gelatin network upon exposure to formulation ingredients, temperature and humidity. Modulated thermal analysis is, therefore, a useful tool for screening the variables influencing the hardness of gelatin capsules.

Transport studies of insulin across rat jejunum in the presence of chicken and duck ovomucoids.

Our aim was to evaluate the transport of insulin across rat jejunum in the presence of ovomucoids and to assess the effect of ovomucoids on intestinal tissue by studying the permeation of a lipophilic and a hydrophilic marker. Rat jejunal segments were mounted in a side-by-side diffusion chamber filled with Krebs bicarbonate buffer, bubbled with 95% O2/5% CO2 at a fixed flow rate and maintained at 37 degrees C. The permeation of insulin, a lipophilic marker ([7- 3H] testosterone) and a hydrophilic marker (D-[1- 14C] mannitol) was evaluated in the presence of 0.5-1.5 microM duck ovomucoid (DkOVM) or chicken ovomucoid (CkOVM). For stability and permeation of insulin in the presence of alpha-chymotrypsin, an enzyme-to-inhibitor ratio of 1:1 and 1:2 was used. In the absence of alpha-chymotrypsin, the permeability coefficient (Papp) of insulin at pH 7.4 was 0.922+/- 0.168 x 10(-7) cm s(-1), which decreased with increasing concentrations of DkOVM or CkOVM. Conversely, the permeation of the hydrophilic and lipophilic marker increased with increasing concentrations of CkOVM and DkOVM. In stability studies, the percentage of drug remaining was found to be 2-fold higher at the 1:2 ratio than with the 1:1 ratio of enzyme to inhibitor. This was in agreement with the 2-fold increase in flux values of insulin in the presence of alpha-chymotrypsin and DkOVM at the 1:2 ratio of enzyme to inhibitor. The decrease in permeation of insulin in ovomucoids was unexpected. Marker transport studies indicated that ovomucoids have the potential to modulate transcellular and paracellular permeability. The flux enhancement of insulin in the presence of alpha-chymotrypsin and DkOVM is encouraging. The use of ovomucoids offers potential to enhance oral delivery of insulin and warrants further investigation.

Analysis of ubidecarenone (CoQ10) aqueous samples using reversed phase liquid chromatography.

A novel method was developed for the quantitative determination of ubidecarenone (CoQ10) in aqueous media using non aqueous reversed phase liquid chromatography. Standards were prepared by melting the compound in Cremophor EL followed by dilution with distilled water. Samples were then analyzed by a Reverse Phase HPLC method using a Waters Novapak C18, 3.9 x 150 mm column. The mobile phase used was methanol: n-hexane (9:1) at a flow rate of 1.5 ml/min. Response of the detector to the analyte was linear (r: 0.999) over the range of 2.5-100 micrograms ml-1, with a limit of detection of 0.17 microgram ml-1. Acetone used to solubilize CoQ10 in the surfactant and Cremophor EL did not interfere with sample analysis. This method provided a convenient and alternative approach to the existing methods that require organic solvent extractions prior to analysis. Besides, this method enabled the separation of major photolytic decomposition products of CoQ10.

Stability characterization of controlled release coprecipitates and solid dispersions.

The present study was conducted to determine the effects of ageing at exaggerated storage conditions on controlled release tablets prepared with indomethacin-Eudragit((R)) coprecipitates (CPs) and solid dispersions (SDs). CPs and SDs compressed as tablets were stored at -20, 4, 37, 45, 55, 37 degrees C/11% RH, 37 degrees C/51% RH and 37 degrees C/91% RH. The samples were analyzed over a period of six months for their dissolution, crystalline reversion and thermal changes. Samples stored at extremely low temperatures, higher temperatures and humidity conditions exhibited a significant decrease in dissolution rates. However, no significant change in the release rates was observed for samples stored at 4 degrees C. The degree of crystallinity increased over a period of time as confirmed by X-ray diffractometry. DSC data demonstrated that indomethacin exists in two polymorphic forms, Form I (mp 160-161 degrees C) and Form II (mp 153-154 degrees C). CPs showed an endotherm of Form I, whereas SDs showed a mixture of Form I and II.

Captopril gastrointestinal therapeutic system coated with cellulose acetate pseudolatex: evaluation of main effects of several formulation variables.

Maintenance of constant drug levels in the body for those drugs that are used in management of hypertension is extremely beneficial. This can be successfully achieved by delivering the antihypertensives as osmotically-controlled drug-delivery system that essentially eliminates the influence of pH on the drug release. The main objective of this study was to evaluate the main effects of the formulation variables on the release of captopril from osmotically-controlled drug-delivery system coated with a custom-made cellulose acetate (CA) pseudolatex reported earlier. A secondary objective was to identify a suitable antioxidant for incorporating in the formulation as the drug undergoes metal-catalyzed oxidative degradation. The drug showed good stability (> or = 90% intact captopril) in solution in the presence of ascorbic acid for a period of 48 h. A seven-factor, 12-run Plackett-Burman screening design was employed to study the main effects of amounts of Polyox(R) N10 and N80, Carbopol(R) 934P and 974P, sodium chloride, orifice size, and % coating weight gain. The response variable was cumulative percent of drug released in 12 h, Y(3), with constraints on lag time Y(1) and time for 50% drug released Y(2)amount of sodium chloride (1.97).

Magnetic resonance imaging--the evaluation of choice in residual shunt after congenital heart disease surgery?

Accurate anatomic diagnosis presents a dilemma in patients with residual shunt after corrective surgery for congenital heart disease. We describe a patient who, after atrial septal defect repair, developed dyspnea and central cyanosis despite normal pulmonary arterial pressures and right heart chamber size. A role for early MRI is suggested.

Limb leads of the electrocardiogram: sequencing revisited.

The six limb leads are normally presented in a format the logic of which is traditional rather than anatomical and does not allow visual interpolation such as is customary with the six chest leads. The sequence: a VL, I, -aVR, II, aVF, III was suggested years ago, and is used in some European countries, particularly Sweden. It provides a better impression of the extent of the changes of inferior infarction and makes the rather neglected lead aVR much more useful, though reversed in polarity. It also provides a more direct indication of the electrical axis, and simplifies comparisons with the frontal plane vectorcardiogram. Because modern digital electrocardiographs can provide the sequenced format, this seems a good time to review the advantages of adopting it.

Platypnea-orthodeoxia as a cause of unexplained hypoxemia in an 82-yr-old female.

We describe an 82-yr-old patient with platypnea-orthodeoxia without identifiable lung disease in whom the diagnosis was suspected because of clinical history, echocardiography, and orthostatic measurement of arterial blood gases. Recumbent and upright cardiac catheterization techniques confirmed the presence of orthostatic variation in the degree of right to left shunt across the fossa ovalis. This was successfully treated by surgical closure of the interatrial communication in the region of the fossa ovalis.

Brucella infective endocarditis. Successful combined medical and surgical therapy.

Five cases of Brucella infective endocarditis are described involving a native aortic valve, two native mitral valves, a mitral valve bioprosthesis, and a ventricular septal defect patch. The diagnosis of Brucella infective endocarditis was established from the clinical features, with a high Brucella serologic titer in each case. Blood and tissue cultures were positive in four of five patients. Two-dimensional echocardiograms demonstrated moderately large vegetations on the three affected native valves and the patch and also revealed the development of vegetation on the mitral bioprosthesis as the disease progressed. All the patients were successfully treated by combined surgical and medical therapy, the latter consisting of co-trimoxazole, tetracycline, and streptomycin/gentamicin for 6 weeks; the affected valves and the ventricular septal defect patch were all replaced. There were no operative deaths and there has been no recurrence of infection to date. One patient died suddenly of an unknown cause 1 year after the operation.

Deriving the 12-lead electrocardiogram from four (EASI) electrodes.

Computerized interpretation of the electrocardiogram has now advanced to computerization of the electrocardiograph, resulting in greatly increased versatility, including the capacity for adapting to a variety of lead systems rather than being tethered to the old Einthoven-Wilson-Goldberger (EWG) system. Many varieties of display beyond the 12-lead ECG are also available in software. To date, these new and interesting capabilities have scarcely been exploited. The EASI lead system uses the E, A, and I electrode positions of the Frank lead system, plus an electrode, S, positioned over the upper end of the sternum and, if necessary, ground (anywhere convenient). Its outputs form quasi-xyz signals, x'y'z', that can be approximately transformed into xyz signals by means of a matrix derived from the EASI lead vectors. The result forms a good basis for deriving the 12-lead ECG, using previously published coefficients for the Frank lead system. The match with the conventional ECG can then be improved by statistical means. The results are surprisingly good, and certainly of clinical value. Recent widespread interest in silent ischemia and its detection through Holter monitoring suggests an immediate application which has been rendered practical by the recent introduction of three-channel recorders. The EASI electrode positions give technically satisfactory Holter recordings. Very compact three-channel, multiplexed, radio telemetry equipment is now commercially available and provides another application for the EASI 12-lead ECG.(ABSTRACT TRUNCATED AT 250 WORDS)