Regulation of a novel cell differentiation-associated gene, JWA during oxidative damage in K562 and MCF-7 cells

Oxidative stress, or the production of oxygen-centered free radicals, has been hypothesized as the major source of DNA damage that can lead to a variety of diseases including cancer. It is known that 8-hydroxy-deoxyguanosine (8-oxo-dG) is a useful biomarker of oxidative DNA damage. Our recent data showed that JWA, initially being cloned as a novel cell differentiation-associated gene, was also actively responsive to environmental stressors, such as heat-shock, oxidative stress and so on. In the present study, we have applied a modified comet assay and bacterial repair endonucleases system (endonuclease III and formamidopyrimidine glycosylase) to investigate if JWA is involved in hydrogen peroxide (H2O2)-induced DNA damage and repair in K562 and MCF-7 cells, and to demonstrate if the damage is associated with 8-oxo-dG. The results from the comet assay have shown that the average tail length and the percentage of the cells with DNA tails are greatly induced by H2O2 treatment and further significantly enhanced by the post-treatment of repair endonucleases. The H2O2-induced 8-oxo-dG formation in K562 and MCF-7 cells is dose-dependent. In addition, the data have clearly demonstrated that JWA gene expression is actively induced by H2O2 treatment in K562 and MCF-7 cells. The results suggest that JWA can be regulated by oxidative stress and is actively involved in the signal pathways of oxidative stress in the cells.

Isoflavone conjugates are underestimated in tissues using enzymatic hydrolysis

Many health effects of soy foods are attributed to isoflavones. Isoflavones upon absorption present as free form, glucuronide, and sulfate conjugates in blood, urine, and bile. Little is known about the molecular forms and the relative concentrations of soy isoflavones in target organs. Acid hydrolysis or enzymatic hydrolysis (glucuronidases and sulfatases) was used to study isoflavone contents in the heart, brain, epididymis, fat, lung, testis, liver, pituitary gland, prostate gland, mammary glands, uterus, and kidney from rats fed diets made with soy protein isolate. The heart had the lowest isoflavone contents (undetectable), and the kidney had the highest (1.8 +/- 0.6 nmol/g total genistein; 3.0 +/- 1.1 nmol/g total daidzein). Acid hydrolysis released 20-60% more aglycon in tissues than enzymatic digestion (p < 0.05), and both hydrolysis methods gave the same level of isoflavones in serum. Approximately 28-44% of the total isoflavone content within the liver was unconjugated aglycon, and the remainder was conjugated mainly as glucuronide. The subcellular distribution of total isoflavones was 55-60% cytosolic and 13-16% in each of the nuclear, mitochondrial, and microsomal fractions. These results demonstrated that (1) soy isoflavones distribute in a wide variety of tissues as aglycon and conjugates and (2) the concentrations of isoflavone aglycons, which are thought to be the bioactive molecules, are in the 0.2-0.25 nmol/g range, far below the concentrations required for most in vitro effects of genistein or daidzein.

Effects of fenvalerate on progesterone production in cultured rat granulosa cells

In this study, primary serum-free cultured rat granulosa cells (rGCs) were used as a cellular model to investigate the effects of fenvalerate on progesterone production. Various concentrations (0, 1, 5, 25, 125 and 625 microM) of fenvalerate were added to the cell cultures for 24 h. rGCs were stimulated by compounds such as follicle-stimulating hormone (FSH), 8-bromo-cAMP or 22(R)-hydroxycholesterol (22R-HC). Progesterone production and intracellular cAMP content were measured in control and treated groups. Expression of P450 side chain cleavage enzyme (P450scc) and steroidogenic acute regulatory protein (StAR) were monitored by real-time PCR and Western blotting. Results showed that fenvalerate inhibited basal progesterone production in rGCs in the absence of stimulators. This inhibition was stronger in the presence of FSH and was not fully reversed by 8-bromo-cAMP or 22R-HC. The increase of cAMP content, stimulated by FSH, was inhibited by fenvalerate implicating that the intracellular cAMP-dependent signal pathway was involved. Fenvalerate reduced mRNA and protein expression of P450scc. These results suggested that multi-site inhibition of progesterone production by fenvalerate including a cAMP-dependent protein kinase pathway and reduction on P450scc gene expression and/or its enzymatic activity in rGCs.

Terephthalic acid occupational exposure and its effect on organ functions in fiber workers

OBJECTIVES

: To investigate the exposure to terephthalic acid (TPA), and to evaluate it's effects on organ function including the potential risk factors for uroliths and bladder tumor to TPA.

METHODS

: Exposure-response modeling was carried out in a cohort of 141 TPA exposure workers and three subgroups were classified according to their urine TPA concentration. The control group consisted of 77 workers with no exposure to TPA dust. The inhalatory exposure of the application workers was estimated from biological monitoring data. Urine and blood samples were collected from all workers before and after work shift to monitor variables of liver, kidney, and lung. Haematological variables and serum biochemistry were valued, pulmonary functions were tested, and ion changes in both serum and urine were measured.

RESULTS

: Increased urinary excretion of TPA (0-5mmol/molCr after the shift) reflected occupational workers TPA exposure. We also observed the exposure-response relations for the intensity of TPA exposure and the urine variables. Increased serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) but within normal range is not increased. The slightly increased serum angiotensin-converting enzyme activity (SACE) was considered to be related to particulate of airborne TPA dust inhalation. No difference between referents and workers exposed to TPA was found for haematological variables.

CONCLUSIONS

: No clinical organ dysfunctions were found in this investigation working with TPA. However, special precautions are still necessarily taken to avoid excessive or prolonged contact.

[Effects of mono(2-ethylhexyl) phthalate on testosterone biosynthesis in leydig cells cultured from the rat testis]

OBJECTIVE

To investigate the effects of mono(2-ethylhexyl) phthalate(MEHP), the primary metabolite of di(2-ethylhexyl) phthalate (DEHP), on testosterone biosynthesis in Leydig cells cultured from the Sprague Dawley rat testis.

METHODS

Based on the primary Leydig cell culture model, MEHP exposure groups involved control (0 micromol/L), 62.5, 125, 250, 500 and 1000 micromol/L. We observed mitochondria activity with the MTT method, measured the testosterone level with RIA and determined steroidogenesis acute regulatory protein (StAR) mRNA expression with RT-PCR.

RESULTS

After Leydig cells were exposed to MEHP for 24 hours, the activity of mitochondria enhanced evidently at 250 micromol/L and then declined markedly at 1000 micromol/L compared with the control group (P < 0.01). The testosterone level showed an increasing tendency in both basal and hCG-stimulated states with statistical significance at 250 and 500 micromol/L compared with the control group (P < 0.01). However, the expression of StAR mRNA appeared unchanged at 62.5, 125 or 250 micromol/L, but exhibited a decreasing tendency at 500 and 1000 micromol/L (P < 0.01).

CONCLUSION

ME- HP directly affected the activity of mitochondria and testosterone biosynthesis of the Leydig cells in vitro. StAR, the regulator of cholesterol transport into mitochondria, might not be responsible for the increase of testosterone biosynthesis induced by MEHP.

JWA--a novel environmental-responsive gene, involved in estrogen receptor-associated signal pathway in MCF-7 and MDA-MB-231 breast carcinoma cells

The pyrethroid insecticide fenvalerate and the organophosphorus insecticide phoxim are now the most widely used agents for indoor pest control in China. Fenvalerate was shown to mimic estrogenic activity, whereas phoxim did not induce similar effects. Our previous studies demonstrated that JWA, a novel retinoic acid-inducible and cytoskeleton-associated gene, is also a potential environmental-responsive gene with increased expression to oxidative and heat-shock stresses. In the present study, the influence of both fenvalerate and phoxim was examined on the expression of JWA in MCF-7 (ER+) and MDA-MB-231 (ER-) human breast carcinoma cell lines. Concentrations of 0.01, 1, and 100 micromol/L of fenvalerate or phoxim were selected to treat both MCF-7 and MDA-MB-231 cells at 1, 3, and 5 d, respectively. The MTT results only showed that fenvalerate stimulated MCF-7 cell proliferation. Western blot assay was employed to detect the expressions of JWA and heat-shock proteins (hsp27 and hsp70). The results showed that after treatment with fenvalerate, both JWA and hsp70 showed similar expression patterns in the both cell lines; however, all the expression patterns of JWA, hsp27, and hsp70 were evidently reversed between ER+ and ER- cells. In addition, phoxim-treated cells showed a concentration-dependent relationship in JWA expression at all time points. These results suggest that JWA has similar functions with respect to hsp27 and hsp70, and might be a novel signal molecule in estrogen receptor-related signal transduction pathways in mammalian cells.

Genotoxic Effects on Spermatozoa of Carbaryl-Exposed Workers

Carbaryl, one of the most important insecticides, is widely produced and used. To explore carbaryl-induced genotoxic effects of spermatozoa, particularly DNA damage and chromosome aberrations (CA), we first examined conventional semen parameters, the progression and motion parameters of the spermatozoa among 16 carbaryl-exposed workers and 30 internal and external control individuals. Sperm DNA damage represented as positive percentage of DNA fragmentation was detected by a modified terminal deoxy-nucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay. Then numerical CA of chromosome X, Y, and 18 were investigated by multicolor fluorescence in situ hybridization (FISH). The results showed significant differences in the percentage of sperm abnormality between carbaryl-exposed group and the external control group (p = 0.008). Mean (+/-SD) percentage of spermatozoa with fragmented DNA in carbaryl-exposed group (21.04 +/- 8.88%) was significantly higher than those in the internal (13.36 +/- 12.17%) and external control groups (13.92 +/- 7.15%), respectively (p = 0.035 and p = 0.030). Using FISH, we observed the frequency of sperm sex chromosome disomy was 0.661 +/- 0.238% in the exposed group, which was significantly higher than that in the external control group (0.386 +/- 0.140%) (p = 0.001), and the carbaryl-exposed group (0.276 +/- 0.126%) had an elevated chromosome 18 disomy compared with the internal (0.195 +/- 0.094%) and external control groups (0.124 +/- 0.068%), respectively (p < 0.05 and p < 0.01). In addition, carbaryl-exposed donors had significantly higher sperm nullisomic frequencies of sex chromosomes and chromosome 18 than the external controls (p < 0.01) but not the internal controls. In summary, the frequencies of aneuploidy and numerical CA showed significant differences between exposed group and control groups (p < 0.05 and/or p < 0.01). Moreover, positive correlations were found between sex chromosome disomy, aneuploidy rate, and morphologic abnormalities in spermatozoa of all donors (r = 0.564 and r = 0.555, p < 0.01). Our findings suggested that carbaryl might induce morphologic abnormalities and genotoxic defects of spermatozoa among exposed workers by causing DNA fragmentation and numerical CA in spermatogenesis as a potential genotoxicant. The evidence also indicated that the spermatotoxicity induced by carbaryl exposure might be related to adverse reproductive outcomes.

Study on the relation between occupational fenvalerate exposure and spermatozoa DNA damage of pesticide factory workers

AIMS

To determine sperm nuclear DNA integrity and to investigate the relation between fenvalerate (FE) exposure and spermatozoa DNA damage.

METHODS

Sperm DNA fragmentation was detected by a modified alkaline single cell gel electrophoresis (Comet) assay and a terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) assay. The olive tail moment (OTM) and percentage tail DNA were measured by the Comet assay, and cell positive percentage was measured by the TUNEL assay for DNA damage evaluation.

RESULTS

The DNA integrity of spermatozoa of external and internal control groups were both significantly greater than that of the FE exposed group. The median value of tail DNA percentage in the exposure group was 11.30, which was significantly higher than 5.60 in the internal control group and 5.10 in the external control group. The median value of OTM was 3.80 in the exposure group, significantly higher than 1.50 in the internal control group and 2.00 in the external control group. Mean cell positive was 31.2% in the exposure group, significantly higher than 17.4% in the internal control and 19.6% in the external control groups. Cell positive (%) was significantly correlated with tail DNA percentage and with OTM of whole subjects (n = 63).

CONCLUSIONS

Results showed that occupational FE exposure is associated with an increase in sperm DNA damage. A combination of the Comet and TUNEL assays would offer more comprehensive information for a better understanding of sperm DNA damage, and the biological significance of sperm DNA damage in sperm function and male infertility.

Alterations of FSH-stimulated progesterone production and calcium homeostasis in primarily cultured human luteinizing-granulosa cells induced by fenvalerate

Fenvalerate, a synthetic pyrethroid, is widely used in agriculture and other domestic applications in China. Recently, Fenvalerate has been suspected to be one of the endocrine-disrupting chemicals (EDC). In this study, we investigated the effects of fenvalerate on follicle-stimulating hormone (FSH)-stimulated progesterone (P4) production by human ovarian luteinizing-granulosa cells (hGLCs). After 24 h incubation, fenvalerate inhibited FSH-stimulated P4 production. At the same time, FSH-stimulated cAMP also decreased. Due to calcium and Ca2+ -calmodulin (CaM) system involving gonadotropin-stimulated steroidogenesis by granulosa cells, we then evaluated the effects of fenvalerate on trifluoperazine (TFP)- and verapamil-driven FSH-stimulated P4 production. The results showed that calcium or calmodulin might play a role in fenvalerate-induced alterations in FSH-stimulated P4 biosynthesis. Then, the effects of fenvalerate on calcium homeostasis in hGLCs were studied. The result showed that 5 microM fenvalerate induced a slow increase in [Ca2+]i in hGLCs by using a fluorescent Ca2+ indicator fluo-3/AM. The changes in total concentration of CaM in hGLCs induced by fenvalerate were evaluated by a method of immunofluorescence. There is a significant increase in all treated groups. In summary, fenvalerate could inhibit FSH-stimulated P4 production. Also, fenvalerate interferes with calcium homeostasis in hGLCs. The effects of fenvalerate on FSH-stimulated ovarian steroidogenesis may be mediated partly through calcium signal.

Study of prostaglandin receptors in mitochondria on apoptosis of human lung carcinoma cell line A549

PGs (prostaglandins) are synthesized through the cyclo-oxygenase (COX-1 and -2) pathway in a variety of cells in response to various physiological stimuli. All cells require at least one pathway for apoptosis, and mitochondrial play a central role in regulation of apoptosis. In a previous study, incubation of A549 cells with NS-398 (a COX-2-specific inhibitor) induced apoptosis and inhibited cell proliferation, and the concentrations of different PGs between various cellular compartments were found to be changed. To determine whether PG receptors are involved in this regulation, Western-blot analyses were performed specific for PGE2 (EP receptors) and PGF2α (FP receptor) receptors, which were expressed in A549 cells. Western-blot analysis revealed that mitochondria that were isolated from A549 cells expressed EP receptors (EP2, EP3 and EP4), whereas FP receptors were undetectable. EP receptors (EP1, EP3 and EP4) and FP receptors were detected from A549 cell membrane. These results suggest that the change of PG production in A549-cells-induced cancer cell apoptosis might be related to the different expressions of EP and FP receptors in cell and mitochondrial membrane.

Cancellous screw fixation for femoral neck fractures: one hundred and sixteen patients

INTRODUCTION

This paper evaluates the efficacy and safety of the use of cancellous screw fixation in the treatment of intracapsular femoral neck fractures in our local population.

MATERIALS AND METHODS

A retrospective analysis of the results of 116 cases that were performed in Singapore General Hospital and Changi General Hospital over a 2-year period was undertaken. The minimum period of follow-up was 2 years.

RESULTS

The median age of the study group was 71 years and approximately two-thirds were females. There were 104 (90%) cases of undisplaced (Garden 1 and 2) fractures and 12 (10%) displaced (Garden 3 and 4) fractures. The specific complication rate was much higher in the displaced group of patients. At 2 years' postoperation, 85% returned to their premorbid level of ambulation and 90% reported good pain relief. The 1-year mortality rate was 7%.

CONCLUSION

Cancellous screw fixation is a relatively safe and useful operation. It achieved our aim of returning most patients to their pre-fracture level of ambulation and providing good pain relief.

Rapid Identification of Yeasts Commonly Found in Positive Blood Cultures by Amplification of the Internal Transcribed Spacer Regions 1 and 2

A multiplex PCR method using one universal and eight species-specific primers was developed to rapidly identify eight yeast species found in positive blood cultures. The species-specific primers were designed from the internal transcribed spacer regions 1 and 2 of the rRNA gene, whereas the universal primer was located at the 26S rRNA gene. The eight species were Candida albicans, Candida glabrata, Candida guilliermondii, Candida krusei, Candida lusitaniae, Candida parapsilosis, Candida tropicalis, and Cryptococcus neoformans. The PCR products (116 to 630 bp) were different in length and could be effectively separated and recognized by polyacrylamide gel electrophoresis. By testing 234 positive blood cultures (237 isolates), 234 (98.7%) isolates of the above eight species were correctly identified by the multiplex PCR. The present method is simple to perform and can be completed within 6 h.

Ion trap mass spectrometry of fluorescently labeled nanoparticles

Mass spectra of fluorescently labeled polystyrene nanoparticles have been obtained using a combined technique of matrix-assisted laser desorption/ionization (MALDI), laser-induced fluorescence (LIF), and a dual quadrupole ion trap mass spectrometer. The spectrometer is designed in such a way that the first trap serves as a trapping and mass-analyzing device, while the second trap serves to capture and concentrate the ions ejected from the first trap for fluorescence detection. An enhancement in the LIF signal by more than 3 orders of magnitude is achieved with the help of the second trap, making mass/charge (m/z) analysis of the nanoparticles possible. Additional unique features of this mass spectrometer include that frequency scan (0.5-50 kHz) at a constant voltage (200 V), instead of voltage scan at a constant frequency, is implemented to widen the spectral analysis range of the instrument. The implementation has allowed the spectrometer to operate at relatively high buffer gas pressures (50 mTorr), crucial for effective trapping of the nanometer-sized particles generated by MALDI. We present in this report the first mass spectra of fluorescently labeled nanoparticles with a size of 27 nm using this new mass spectrometric approach. The utility of this method in the study of biological macromolecules or particles is demonstrated with dye-labeled IgG.

A case of Bizarre Parosteal Osteochondromatous Proliferation of the hand

We report a case of Bizarre Parosteal Osteochondromatous Proliferation (BPOP) of the hand that was initially misdiagnosed as an osteochondroma. BPOP, although a benign lesion, behaves aggressively with rapid growth and high risk of local recurrence after local resection. The distinguishing features of BPOP as opposed to an osteochondroma are discussed.

Determination of St. John's wort components in dietary supplements and functional foods by liquid chromatography

St. John's wort (Hypericum perforatum L.) preparations, a top-selling botanical dietary supplement used primarily as an antidepressant, has recently been used as an ingredient in some food products sold as functional foods. A rapid extraction technique followed by a liquid chromatographic (LC) method was developed to determine 4 characteristic bioactive compounds (pseudohypericin, hypericin, hyperforin, and adhyperforin) from St. John's wort in dietary supplements and functional foods to which it was added. Solid samples, including dried leaf/flower mixture, dietary supplement capsules, tea bags, puff and snack bar, were extracted with methanol by sonication. Noncarbonated, fruit-flavored drinks were centrifuged and mixed with methanol. Compounds were then determined by isocratic, reversed-phase LC with UV detection at 2 wavelengths and further identified or confirmed by photodiode array spectra and LC/mass spectrometry. Within-laboratory method variations (% RSD) were satisfactory. Very low amounts, if any, of the 4 components were found in drink and puff samples, and none was found in the snack bar. The methods developed provide a useful means for the determination of St. John's wort components in dietary supplements and functional foods.

Inactivation of thyroid peroxidase by soy isoflavones, in vitro and in vivo

Soy-containing foods and dietary supplements are widely consumed for putative health benefits (e.g. cancer chemoprevention, beneficial effects on serum lipids associated with cardiovascular health, reduction of osteoporosis, relief of menopausal symptoms). However, studies of soy isoflavones in experimental animals suggest possible adverse effects as well (e.g. enhancement of reproductive organ cancer, modulation of endocrine function, anti-thyroid effects). This paper reviews the evidence in humans and animals for anti-thyroid effects of soy and its principal isoflavones, genistein and daidzein.

The growth and development of orthopaedic sports medicine in Singapore

Orthopaedic sports medicine is currently a well established subspecialty of orthopaedic surgery in Singapore. It had its beginnings in the late 1960s and has since grown to be one of the major orthopaedic subspecialties. Knee, shoulder and ankle injuries constitute the majority of cases seen by the orthopaedic sports medicine specialists. Significant scientific contributions to the international literature have been made by our specialists over the years. Today, Singapore is a regional hub for the provision of orthopaedic sports medicine care and training.

Optical detection and charge-state analysis of MALDI-generated particles with molecular masses larger than 5 MDa

Charged polystyrene nanoparticles are generated by matrix-assisted laser desorption/ionization (MALDI) and detected by laser-induced fluorescence (LIF) in a quadrupole ion trap. Employing the LIF technique, observations of individual fluorescent nanospheres (27 nm in diameter and containing 180 fluorescein dye equivalents) have been achieved with an average signal-to-noise ratio of approximately 10. With the trap operating at a frequency around 5 kHz, charge state analysis of the particles reveals that the number of charges carried by the spheres is between 1 and 10. It suggests a mass-to-charge ratio (m/z) in the range of 10(5)-10(6) for the MALDI-generated particles. To effectively trap such large particles (m > 5 MDa), damping of the particles' motions by using approximately 50 mTorr He buffer gas is absolutely required. Similar findings are obtained for particles with a nominal size of 1 microm in diameter, demonstrating that production of charged particles with a molecular mass as high as 10(12) Da is possible using the MALDI technique.

Extremity osteosarcoma--a Southeast Asian experience

INTRODUCTION

We present our experience with limb salvage emphasising the use of vascularised bone grafts in combination with autoclaved tumour bone for limb salvage in osteosarcoma.

MATERIALS AND METHODS

Thirty-six cases with extremity osteosarcoma, all of which were managed at a single institution between 1980 and 1999, were reviewed at a mean follow-up of 9 years (range, 10 months to 200 months). There were 26 patients who underwent limb salvage surgery and 10 patients who had amputation.

RESULTS

In the limb salvage group, 12 bone defects were bridged using vascularised bone grafts alone while autoclaved tumour bone was used for reconstruction in the remaining 14 patients. In these 14, there were 10 with autoclaved tumour bone and vascularised bone, 2 with autoclaved bone and non-vascularised bone and 2 with autoclaved bone alone. The joint was preserved in 13 of the 26 reconstructions. Of these, 11 involved preservation of the knee joint contributing to a quantum gain in function with 84% good and excellent results. The actuarial survival was 64% at 2 years and 48% at 5 years, with no significant difference between ablation and limb salvage.

CONCLUSION

The use of the autoclaved bone provided yet another effective alternative for bridging large defects following resection of high grade tumours.

Mass spectrometric determination of p-nonylphenol metabolism and disposition following oral administration to Sprague-Dawley rats

Isomers of 4-nonylphenol (NP), which are important industrial compounds and environmental breakdown products from widely used surfactants, have estrogenic activity in vitro and in vivo that has prompted interest in its potential for modulation of endocrine function in humans and wildlife. Mass spectrometry was used to quantify NP and metabolites in serum and endocrine-responsive tissues from dietary exposure in Sprague-Dawley rats. Tissue accumulation of NP aglycone was observed despite the predominance of glucuronidation in blood. Serum toxicokinetics of total NP, measured following gavage administration, showed rapid absorption and elimination (average half-times 0.8 and 3.5 h, respectively). NP was similarly administered by gavage to pregnant dams and total and aglycone NP were measured in dam serum and fetuses to show placental transfer into serum and brain. These data provide a basis for future correlations of biologic effects observed following dietary exposure in rats with those predicted from environmental exposures to humans.

Single-particle mass spectrometry of polystyrene microspheres and diamond nanocrystals

High-resolution mass spectra of single submicrometer-sized particles are obtained using an electrospray ionization source in combination with an audio frequency quadrupole ion-trap mass spectrometer. Distinct from conventional methods, light scattering from a continuous Ar-ion laser is detected for particles ejected out of the ion trap. Typically, 10 particles are being trapped and interrogated in each measurement. With the audio frequency ion trap operated in a mass-selective instability mode, analysis of the particles reveals that they all differ in mass-to-charge ratio (m/z), and the individual peak in the observed mass spectrum is essentially derived from one single particle. A histogram of the spectra acquired in 10(2) repetitions of the experiment is equivalent to the single spectrum that would be observed when an ion ensemble of 10(3) particles is analyzed simultaneously using the single-particle mass spectrometer (SPMS). To calibrate such single-particle mass spectra, secular frequencies of the oscillatory motions of the individual particle within the trap are measured, and the trap parameter qz at the point of ejection is determined. A mass resolution exceeding 10(4) can readily be achieved in the absence of ion ensemble effect. We demonstrate in this work that the SPMS not only allows investigations of monodisperse polystyrene microspheres, but also is capable of detecting diamond nanoparticles with a nominal diameter of 100 nm, as well.

Development of a topical suspension containing three active ingredients

The objective of this study was to develop a topical suspension that contains sarafloxacin hydrochloride (1 mg/mL), triamcinolone acetonide (1 mg/mL), and clotrimazole (10 mg/mL), and is stable at room temperature (15-28 degrees C) for clinical usage. Due to the difference in the physicochemical properties and chemical stability profiles of these three active ingredients, it is a challenge to develop a stable suspension formulation containing these three drugs. In this study, the stability of these drugs in different buffer solutions was determined under different accelerated isothermal conditions. The Arrhenius equation was subsequently utilized to predict the room-temperature stability of these three drugs in these buffer solutions. By knowing the room-temperature solubility of the drugs in the buffer solution, the stability of the drugs in suspension was predicted. As a result, a 0.02 M phosphate buffer (pH 7.0) containing 0.02% (w/v)polysorbate 20, 1% (w/v) NaCl, and 0.1% (w/v) EDTA was determined to be an acceptable medium. In addition, 0.35% (w/v) high-viscosity carboxymethylcellulose (HV-CMC) was first selected as the suspending agent to enhance the redispersibility of the suspension. Stability data further supported that all three drugs were stable in the suspension containing HV-CMC with less than 5% potency loss for at least 6 months at 40 degrees C and 12 months at 25 degrees C. However, the viscosity drop of this HV-CMC formulation at 25 degrees C and 40 degrees C became a product stability concern. To improve the viscosity stability of the suspension, the medium-viscosity carboxymethylcellulose (MV-CMC) was selected to replace the HV-CMC as the suspending agent. The optimal combination of MV-CMC and sodium chloride in achieving the most desirable dispersion properties for the formulation was determined through the use of a 32 factorial design. The optimal formulation containing 1% MV-CMC and 1% sodium chloride has shown improved viscosity stability during storage and has been used for clinical studies.

Metastasis of an adenocarcinoma of the stomach to the 4th metacarpal bone

Metastatic tumours of the hand are uncommon. The majority of these tumours affect the phalanges and the primary tumours are usually bronchogenic in origin, with breast and kidney tumours next in frequency. Metastatic gastrointestinal to the hand is rare and usually from the colon. We report a case of poorly differentiated adenocarcinoma of the stomach antrum presenting with a metastatic lesion to the right 4th metacarpal bone. A review of the literature is included.

Conservative treatment of redisplaced Colles' fractures in elderly patients older than 60 years old - anatomical and functional outcome

A retrospective study was carried out to compare the functional outcome in two groups of patients who were 60 years old or older. One group had Colles' fractures, which had been reduced and did not redisplace. The other group's fractures redisplaced and were treated conservatively. Of the 11 patients in the first group, 82% had excellent or good functional outcome, which was not significantly different when compared with the second group of 25 patients with 68% having excellent or good functional outcome.

T cell responses modulated through interaction between CD8alphaalpha and the nonclassical MHC class I molecule, TL

The thymus leukemia antigen (TL) is a nonclassical class I molecule, expressed abundantly on intestinal epithelial cells. We show that, in contrast to other major histocompatibility complex (MHC) class I molecules that bind CD8alphabeta, TL preferentially binds the homotypic form of CD8alpha (CD8alphaalpha). Thus, TL tetramers react specifically to CD8alphaalpha-expressing cells, including most intestinal intraepithelial lymphocytes. Compared with CD8alphabeta, which recognizes the same MHC as the T cell receptor (TCR) and thus acts as a TCR coreceptor, high-affinity binding of CD8alphaalpha to TL modifies responses mediated by TCR recognition of antigen presented by distinct MHC molecules. These findings define a novel mechanism of lymphocyte regulation through CD8alphaalpha and MHC class I.