Characterization of Aerosols of Human Recombinant Deoxyribonuclease I (rhDNase) Generated by Jet Nebulizers

Recombinant human deoxyribonuclease I (rhDNase) is a new therapeutic agent developed to improve clearance of purulent sputum from the human airways. It is delivered by inhalation. Four jet nebulizers, T Up-Draft II (Hudson), Customized Respirgard II (Marquest), Acorn II (Marquest), and Airlife Misty (Baxter), were evaluated in vitro for their ability to deliver aerosols of rhDNase. The aerosols were generated from 2.5-mL aqueous solutions of rhDNase, at concentrations of either 1 or 4 mg/mL. In all experiments, the Pulmo-Aide Compressor (De Vilbiss) was used to supply the air to the nebulizers. Between 20 and 28% of the rhDNase dose initially placed in the nebulizers was delivered to the mouthpiece in the respirable range (1-6 µm). Evaluation of the rhDNase following nebulization in all four devices indicated that there was no loss in enzymatic activity and no increase in aggregation. Circular dichroism spectrophotometry indicated there was no change in either the secondary or the tertiary structure in rhDNase following nebulization. These results show that all four nebulizers are essentially equivalent in their ability to deliver respirable doses of rhDNase in an intact, fully active form. Changing the concentration of the solution in the nebulizer from 4 to 1 mg/mL rhDNase leads to a proportional reduction in the respirable dose delivered to the mouthpiece.     

Contrasting roles of leu(356) in the human CCK(1) receptor for antagonist SR 27897 and agonist SR 146131 binding

A new highly specific, potent non-peptide agonist for the cholecystokinin subtype 1 receptor (CCK(1)), SR 146131 (2-[4-(4-chloro-2, 5-dimethoxyphenyl)-5-(2-cyclohexyl-ethyl)-thiazol-2-ylcarbamoyl ]-5, 7-dimethyl-indol-1-yl-1-acetic acid) was recently described [Bignon, E., Bachy, A., Boigegrain, R., Brodin, R., Cottineau, M., Gully, D., Herbert, J.-M., Keane, P., Labie, C., Molimard, J.-C., Olliero, D., Oury-Donat, F., Petereau, C., Prabonneaud, V., Rockstroh, M.-P., Schaeffer, P., Servant, O.Thurneyssen, O., Soubrié, P., Pascal, M., Maffrand, J.-P., Le Fur, G., 1999. SR 146131: a new, potent, orally active and selective non-peptide cholecystokinin subtype I receptor agonist: I. In vitro studies. J. Pharmacol. Exp. Ther. 289, 742-751]. From binding and activity assays with chimeric constructs of human CCK(1) and the cholecystokinin subtype 2 receptor (CCK(2)) and receptors carrying point mutations, we show that Leu(356), situated in transmembrane domain seven in the CCK(1) receptor, is a putative contact point for SR 146131. In contrast, Leu(356) is probably not in contact with the CCK(1) receptor specific antagonist SR 27897 (1-[2-(4-(2-chlorophenyl)thiazol-2-yl)aminocarbonyl indoyl]acetic acid), a compound structurally related to SR 146131, since its replacement by alanine, histidine or asparagine gave receptors having wild-type CCK(1) receptor SR 27897 binding affinity. Previous mutational analysis of His(381), the cognate position in the rat CCK(2) receptor, had implicated it as being involved in subtype specificity for SR 27897, results which we confirm with corresponding mutations in the human CCK(2) receptor. Moreover, binding and activity assays with the natural CCK receptor agonist, CCK-8S, show that CCK-8S is more susceptible to the mutations in that position in the CCK(1) receptor than in the CCK(2) receptor. The results suggest different binding modes for SR 27897, SR 146131 and CCK-8S in each CCK receptor subtype.     

Kinetics and mechanism of tobacco mosaic virus assembly: direct measurement of relative rates of incorporation of 4S and 20S protein.

The mechanism of assembly of tobacco mosaic virus has been investigated under conditions in which the rates of incorporation of the 4S and 20S proteins can each be directly measured by analytical centfrifugation. Under these conditions, pH 6.5, 6.5 degrees C, 0.10 M ionic strength potassium orthophosphate, the protein can be made to exist as a metastable 20S aggregate that is necessary for efficient reconstitution. The overall assembly process consists of an initiation (nucleation) reaction that requires two to three 20S disk aggregates per RNA molecule and is followed by an elongation (growth) reaction. In the elongation phase of assembly the 4S protein is incorporated 50 to 70 times faster than the 20S disk, calculated on the basis of a steady-state kinetic analysis. Therefore, under these conditions, in which the rate of assembly is about 0.06 of that at pH 7, 20 degrees C, 0.10 M ionic strength orthophosphate, the 4S protein preferentially participates in the elongation phase. At this slow reconstitution rate intermediate assembly states (about 70-168 S) can be observed. The kinetics of both protein incorporation and nucleoprotein formation suggest that the elongation process is composed of at least two different, possibly sequential, rate-limiting reactions.     

Management of HBV/HIV-coinfected Patients

Coinfection with hepatitis B virus (HBV) and human immunodeficiency virus (HIV) is common as a result of shared routes of transmission, especially in high-risk groups such as injection drug users and persons with hemophilia. HIV is known to influence the natural history of HBV, hastening progression to end-stage liver disease and cirrhosis. Antiretroviral therapy for HIV, and associated immune reconstitution, may result in immune-mediated liver damage as HBV-infected hepatocytes are targeted. This can lead to liver enzyme elevations that may be misattributed to drug-related toxicity. Thus, it is important that HIV-infected patients be tested for HBV and that clinicians be aware of the possibility of atypical serologic markers of HBV in HIV-infected patients. In managing coinfected patients, control of HIV is the priority. In patients with controlled HIV who are candidates for HBV therapy, the goals are the same as in the HBV-monoinfected population: hepatitis B e antigen seroconversion, liver enzyme normalization, and HBV DNA suppression. Treatment options include interferon-based regimens, lamivudine, adefovir, tenofovir, and entecavir. All of these agents have been shown to be relatively effective in HBV-monoinfected patients. However, few randomized, controlled HBV treatment trials have been conducted in coinfected subjects, and thus additional studies are warranted.     

Highly methylated genes in colorectal neoplasia: implications for screening.

Discriminant markers are required for accurate cancer screening. We evaluated genes frequently methylated in colorectal neoplasia to identify the most discriminant ones. Four genes specifically methylated in colorectal cancer [bone morphogenetic protein 3 (BMP3), EYA2, aristaless-like homeobox-4 (ALX4), and vimentin] were selected from 41 candidate genes and evaluated on 74 cancers, 62 adenomas, and 70 normal epithelia. Methylation status was analyzed qualitatively and quantitatively and confirmed by bisulfite genomic sequencing. Effect of methylation on gene expression was evaluated in five colon cancer cell lines. K-ras and BRAF mutations were detected by sequencing. Methylation of BMP3, EYA2, ALX4, or vimentin was detected respectively in 66%, 66%, 68%, and 72% of cancers; 74%, 48%, 89%, and 84% of adenomas; and 7%, 5%, 11%, and 11% of normal epithelia (P < 0.01, cancer or adenoma versus normal). Based on area under the curve analyses, discrimination was not significantly improved by combining markers. Comethylation was frequent (two genes or more in 72% of cancers and 84% of adenomas), associated with proximal neoplasm site (P < 0.001), and linked with both BRAF and K-ras mutations (P < 0.01). Cell line experiments supported silencing of expression by methylation in all four study genes. This study shows BMP3, EYA2, ALX4, and vimentin genes are methylated in most colorectal neoplasms but rarely in normal epithelia. Comethylation of these genes is common, and pursuit of complementary markers for methylation-negative neoplasms is a rational strategy to optimize screening sensitivity.     

Topical testosterone treatment for chronic allograft failure in liver transplant recipients with recurrent hepatitis C virus

INTRODUCTION: Liver transplant recipients with allograft failure due to recurrent hepatitis C virus (HCV) infection often develop marked muscle wasting and ascites prior to death and are denied repeat liver transplantation. We sought to determine whether topical testosterone therapy is associated with improved muscle mass and survival in patients with chronic allograft failure post-liver transplant. METHODS: We performed a retrospective review of liver transplant recipients with chronic allograft failure. Group 1 patients were treated for >6 months with testosterone gel 1%; group 2 patients were untreated. RESULTS: Fourteen patients were identified with stage 3 or 4 fibrosis, muscle wasting, and allograft failure due to recurrent HCV. Group 1 (n=9) patients had statistically significant improvement in albumin, testosterone, muscle strength, well-being, and MELD/CTP scores, while there was no improvement seen for any of these parameters in group 2 (n=5). There were no deaths in group 1, while four of five patients in group 2 died on average 84 days posttransplant. Adverse effects of testosterone treatment included lower extremity edema (which resolved upon dose adjustment), hypertension, and pruritus. CONCLUSIONS: Topical testosterone gel appears to increase muscle strength, stimulate albumin synthesis, and improve survival in patients with allograft failure post-liver transplant.     

Effects of race, ethnicity, gender, culture, literacy, and social marketing on public health

Societies globally have a long road ahead in eliminating health risks and discrepancies due to race and ethnicity, gender, culture, and illiteracy. In terms of race, for example, females and African-Americans are less likely to be referred for cardiac catheterization, and Caucasians are more likely than minorities to receive pain management in the emergency room. Regarding gender, physiologic differences certainly account for some divergent health outcomes, but they do not explain how women and men have different prevalences of diseases that are not obviously gender-specific. Cultural beliefs play a vital role in determining health choices, and health care professionals need a deeper understanding of these beliefs prior to promoting certain health interventions. Illiteracy may also prevent a person from following health instructions, and the strong association between illiteracy and poverty may exert powerful, negative influences on health outcomes. Employing the characteristics of social marketing (synchronous messages, reinforcement, and actionability) may help society to overcome some of the obstacles.