Analysis of commercial mini-bus accidents

The major challenge in liquid sustained-release oral suspensions is to minimize drug diffusion into the suspending medium and to retain the original properties of the microparticles during storage. Diclofenac wax microspheres prepared by the hydrophobic congealable disperse phase method were formulated as a sustained release suspension and stored at three different temperatures (25, 37 and 45 degrees C) for 3 months, to evaluate the physical and chemical stability of the suspended microspheres. Suspensions of microspheres stored at ambient temperatures were both physically and chemically stable, but at higher temperatures, up to 45 degrees C, there was a decrease in drug release due to scaling and melting on the microsphere surface as observed by scanning electron microscopy. However, on prolonged storage, up to 90 days, especially at 45 degrees C, temperature became a dominant factor causing an increase in drug release. The suspension of diclofenac microspheres was chemically stable for 3 months, while the plain drug suspension exhibited slight degradation.     

Phase I study of suramin combined with doxorubicin in the treatment of androgen-independent prostate cancer

In this study, we determined the maximum tolerated plasma concentration of suramin (within the predetermined study target range) when combined with doxorubicin in the treatment of androgen-independent prostate cancer. Twenty-four patients received suramin dosages based on proportional adjustment of the steady-state plasma suramin concentration to achieve the targeted plasma concentrations of 50-100, 101-150, 151-200, or 201-250 microg/ml. Doxorubicin (20 mg/m2) was administered i.v. over 24 h at weekly intervals. Suramin was given i.v. over 2 h twice weekly. Patients received treatment until dose-limiting toxicity or disease progression. Side effects similar to those reported for suramin and doxorubicin administered as individual agents were observed. Dose-limiting motor neuropathy developed in three patients (13%). Twelve of 24 evaluable patients (50%; 95% confidence interval, 28-71%) and 6 of 10 evaluable patients (60%; 95% confidence interval, 26-88%) had a >50% decrease of prostate-specific antigen and measurable lesions, respectively. The maximum tolerated plasma level of suramin when combined with doxorubicin was 151-200 microg/ml. Future studies on suramin combined with doxorubicin or other agents could be performed using a fixed dosing scheme with a targeted suramin steady-state plasma concentration of 200 microg/ml.     

Haemophilus ducreyi is susceptible to protegrin

Protegrins, potent antimicrobial peptides found in porcine leukocytes, have activity against the sexually transmitted pathogens Neisseria gonorrhoeae, Chlamydia trachomatis, and human immunodeficiency virus type 1. We tested synthetic protegrin 1 (PG-1) for activity against nine isolates of Haemophilus ducreyi, the etiologic agent of chancroid. The test organisms included CIP 542 (the type strain), 35000HP (a human-passaged variant of 35000), 35000HP-RSM2 (an isogenic D-glycero-D-manno-heptosyltransferase mutant of 35000HP), and six clinical isolates. The isolates were epidemiologically unrelated, represented three HindIII ribotypes, and had varying antimicrobial resistance patterns. In bactericidal assays, five isolates were rapidly killed by synthetic PG-1. In radial diffusion assays, all nine isolates were exquisitely sensitive to PG-1. These data highlight the potential of protegrins for development as topical agents to prevent many sexually transmitted diseases, including chancroid.     

Pseudomonas aeruginosa as a cause of infectious diarrhoea

Pseudomonas aeruginosa is not generally considered a cause of infectious diarrhoea. However, it was the predominant organism isolated from the faeces of 23 unrelated, hospital outpatients investigated in the course of a year for persistent (> 1 week duration) diarrhoea. To investigate the possible aetiological role of P. aeruginosa, these patient histories were reviewed and a selection of their faecal isolates were investigated in vitro (n > or = 10) and in vivo (n = 2) for virulence. The patients had a mean age of 60 years, were receiving antibiotics and/or had an underlying illness. Extensive microbiological investigations identified no other potential or recognized enteropathogen in the faeces of 20 of these patients. More than 40% of the isolates tested were able to adhere to HEp-2 cells and exhibited twitching motility (type IV pili), properties indicative of their ability to colonize the human intestine. Cytotoxic activity was demonstrated in bacterium-free cell supernatants of over 80% of isolates; supernatants of four isolates tested in infant mice were weakly enterotoxigenic. Two isolates intragastrically inoculated into clindamycin pre-treated rats established persistent infections and induced signs and symptoms of enteritis. Overall these findings suggest that P. aeruginosa can cause diarrhoea particularly in immunodeficient individuals.     

Topical contrast-enhanced CT and MR dacryocystography: imaging the lacrimal drainage apparatus of healthy volunteers

OBJECTIVE: The purpose of this study was to evaluate the feasibility of administering topical contrast material during helical CT dacryocystography and topical saline solution during MR dacryocystography to reveal the lacrimal drainage apparatus. SUBJECTS AND METHODS: Fourteen healthy volunteers underwent helical CT dacryocystography, MR dacryocystography, or both. Eight of the 14 subjects underwent both techniques; three subjects underwent MR dacryocystography, and three subjects underwent CT dacryocystography. Images were evaluated by two radiologists for degree of visualization of components of the lacrimal drainage apparatus. Each volunteer was questioned about the relative discomfort of contrast material and saline solution administration. RESULTS: The lacrimal drainage system was seen on both CT dacryocystography and MR dacryocystography. CT dacryocystography allowed two-dimensional and three-dimensional reconstructions on which adjacent bone anatomy could be seen. The MR dacryocystography two-dimensional reconstructions and maximum intensity projections also showed the drainage apparatus. However, smaller drainage structures were more consistently seen on CT dacryocystography than on MR dacryocystography. Saline solution was more comfortable than contrast material. CONCLUSION: CT dacryocystography and MR dacryocystography reproducibly and non-invasively revealed the lacrimal drainage apparatus and allowed a better physiologic examination than cannulation dacryocystography. MR dacryocystography can be performed without administration of ionizing radiation or contrast material, but this technique cannot show adjacent bone anatomy and less consistently showed the smaller drainage structures than CT dacryocystography.     

Muscle development: electrical control of gene expression

The electrical activity resulting from stimulation by motor neurons regulates gene expression in skeletal muscle fibres. A recent study has suggested a mechanism by which distinct patterns of electrical stimulus might be integrated to control the contractile properties of these fibres.     

Evidence that the thyrotropin receptor ectodomain contains not one, but two, cleavage sites

TSH receptor (TSHR) cleavage into two subunits (A and B) was explored using two new mammalian cell lines expressing the recombinant receptor; 1) TSHR-10,000 CHO cells overexpressing the TSHR; 2) TSHRmyc cells with a c-myc epitope inserted at residues 338-349. Immunoprecipitation or immunoblotting of TSHR-10,000 cells with mAb to either the A subunit or the B subunit revealed multiple forms of the TSHR: 1) uncleaved receptors of approximately 115 kDa and approximately 100 kDa with complex carbohydrate and high mannose carbohydrate, respectively; 2) two subunit TSHR with an approximately 62 kDa A subunit containing complex carbohydrate. The A subunit was approximately 35 kDa after enzymatic deglycosylation (predicted C-terminus near residue 330). The nonglycosylated B subunit was evident primarily as an approximately 42 kDa band (predicted N terminus near residue 380). The sum of the A and B subunit polypeptide backbones was smaller than the predicted size of the TSHR, a polypeptide backbone (84.5 kDa), raising the possibility that an approximately 5-kDa polypeptide fragment was excised during intramolecular cleavage. This hypothesis was supported by data obtained with the TSHRmyc cells. Thus, mAb to the c-myc epitope and to amino acid residues 22-35 (mAb A10) were equally effective in detecting the single chain forms of the TSHR in these cells. However, the 35 kDa, deglycosylated A subunit was clearly visible on immunoprecipitation with mAb A10 to the TSHR amino terminus, but not with the anti-myc mAb, indicating loss of the c-myc epitope at residues 338-349. Further, even though the A subunit was not detected in TSHRmyc cells with anti-myc mAb, 125I-TSH cross-linking to the cell surface showed similar A subunit expression in TSHRmyc and wild-type TSHR expressing cells. In summary, our study provides a surprising and novel finding for G protein-coupled receptors. Contrary to the prevailing concept of one cleavage site in the TSHR, we present evidence that there are, in fact, two such sites. The TSHR, like insulin, may release a C peptide during intramolecular cleavage into two subunits.     

Obsessive compulsive disorder following head injury

An epithelial ovarian tumor with steroid production was examined in a 70-year-old postmenopausal female. The stromal cells of this tumor were rather dense and occasionally characterized by luteinization or hyperthecosis, which has been associated with steroidogenesis. Subcellular visualization using confocal laser scanning microscopy (CLSM) successfully led to the identification of 3 beta-hydroxysteroid dehydrogenase (HSD) in both mitochondria-like small particles and endoplasmic reticulum-like linear profiles, and P450-aromatase also in endoplasmic reticulum-like linear profiles, on the three-dimensional images.     

Physical and biological predictors of changes in whole-lung function following thoracic irradiation

PURPOSE: To develop methods of predicting the pulmonary consequences of thoracic irradiation (RT) by prospectively studying changes in pulmonary function following RT. METHODS AND MATERIALS: 100 patients receiving incidental partial-lung irradiation during treatment of tumors in or adjacent to the thorax had whole-lung function assessed via symptoms and pulmonary function tests (PFTs: FEV1-forced expiratory volume 1 s; DLCO-diffusion capacity) before and repeatedly 6-48 months following RT. All had computed tomography-based three-dimensional (3D) dose calculations with lung density heterogeneity corrections for dose-volume histogram (DVH) and normal tissue complication probability (NTCP) calculations. Functional DVHs (DVfH) based on SPECT (single photon emission computed tomography) lung perfusion scans, and serial transforming growth factor-beta (TGF-beta1) levels were available in 50 and 48 patients, respectively. The incidence and severity of changes in whole-lung function were correlated with clinical, physical, and biological factors. Exploratory statistical analyses were performed using chi-square, Pearson correlations, logistic regression, and multiple linear regression. RESULTS: RT-induced symptoms developed in 21 patients. In the overall group, the single best predictor for the development of symptoms was the NTCP (p < 0.05). Pre-RT PFTs alone were less predictive (p = 0.1 for FEV1, p = 0.08 for DLCO). A multivariate model based on pre-RT DLCO and CT-based NTCP was strongly predictive for the development of symptoms (p < 0.001). NTCPs based on SPECT-derived DVf Hs and TGF-beta1 levels did not appear to provide additional predictive value. The presence or absence of pulmonary symptoms was correlated with the decline in PFT 6 months following RT (p < 0.05). In the overall group, the degree of decline in PFTs was not well correlated with any of the dose-volume variables considered. In patients with "good" pre-RT PFTs, there was a relationship between the percent reduction in PFT and dose-volume parameters such as the percent of lung volume receiving > 30 Gy (p < 0.05). CONCLUSION: The extent of alteration in whole-lung function (symptoms or PFT changes) appears to be related to both dose-volume and pre-RT PFT parameters. The data suggest that no one variable is likely to be an adequate predictor and that multivariate predictive models will be needed. Additional studies are underway to develop better predictive models that consider physical factors such as the DVH and regional perfusion, as well as biological/clinical factors such as pre-RT PFTs and TGF-beta1.