In the biopharmaceutical industry, mammalian cell culture systems, especially Chinese hamster ovary (CHO) cells, are predominantly used for the production of therapeutic glycoproteins. Glycosylation ...is a critical protein quality attribute that can modulate the efficacy of a commercial therapeutic glycoprotein. Obtaining a consistent glycoform profile in production is desired due to regulatory concerns because a molecule can be defined by its carbohydrate structures. An optimal profile may involve a spectrum of product glycans that confers a desired therapeutic efficacy, or a homogeneous glycoform profile that can be systemically screened for. Studies have shown some degree of protein glycosylation control in mammalian cell culture, through cellular, media, and process effects. Studies upon our own bioprocesses to produce fusion proteins and monoclonal antibodies have shown an intricate relationship between these variables and the resulting protein quality. Glycosylation optimization will improve therapeutic efficacy and is an ongoing goal for researchers in academia and industry alike. This review will focus on the advancements made in glycosylation control in a manufacturing process, as well as the next steps in understanding and controlling protein glycosylation.
This study was conducted to determine whether Pneumocystis carinii dyhydropteroate synthase (DHPS) gene mutations in AIDS patients with P. carinii pneumonia (PCP) are affected by duration of sulfa or ...sulfone prophylaxis and influence response to sulfa or sulfone therapy. The P. carinii DHPS genes from 97 AIDS patients with PCP between 1991 and 1999 from 4 medical centers were amplified, using polymerase chain reaction (PCR), and sequenced. Mutations were observed in 76% of isolates from patients exposed to sulfa or sulfone prophylaxis compared with 23% of isolates from patients not exposed (P = .001). Duration of prophylaxis increased the risk of mutations (relative risk RR for each exposure month, 1.06; P = .02). Twenty-eight percent of patients with mutations failed sulfa or sulfone treatment; mutations increased the risk of sulfa or sulfone treatment failure (RR, 2.1; P = 0.01). Thus, an increased duration of sulfa or sulfone prophylaxis increases the chance of developing a P. carinii mutation. The majority of patients with mutations respond to sulfa or sulfone therapy.
Artemisinin and its derivatives are important new antimalarial drugs. When Plasmodium falciparum -infected erythrocytes are incubated with 10- 3 Hdihydroartemisinin, several malaria-specific proteins ...become labeled. One of these proteins is the P. falciparum translationally controlled tumor protein (TCTP) homolog. In vitro , dihydroartemisinin reacts covalently with recombinant TCTP in the presence of hemin. The association between drug and protein
increases with increasing drug concentration, plateauing at approximately 1 drug/TCTP molecule. By Scatchard analysis, there
appear to be 2 hemin binding sites on TCTP with dissociation constants of â¼18 μ m . When the single cysteine moiety is blocked by pretreatment with iodoacetamide, hemin binding is not affected, whereas drug
binding is reduced by two-thirds. Thus, TCTP reacts with artemisinin in situ and in vitro in the presence of hemin and appears to bind to hemin. The function of the malarial TCTP and the role of this reaction in
the mechanism of action of artemisinin await elucidation.
•There is a lack of geographical research on the production of medical spaces.•Geography can contribute to the assessment of health care transformation.•This study demonstrates health care ...privatization through routine technologies.
Social science researchers interested in human health have generally neglected the production of health care spaces and the experience of medical workers, particularly physicians. Health care researchers have contributed to our knowledge of the discursive and material construction of disease and ill health, the embodied experience of ill-health, and the socio-spatial relations of care networks. Yet, similar developments have been relatively absent in spatialities of medical services. This is particularly true if one looks beyond a few key sites in New Zealand, Canada, and England. This project reviews the geographies of medical services literature and then identifies three key areas which would benefit from greater engagement: macro- and micro-scale interactions, primary care spaces, and a greater range of places. I then use a case study of the privatization of a primary care space in Milwaukee, Wisconsin to illustrate the usefulness of geographic approaches for medical service research.
Failures of prophylaxis against Pneumocystis carinii pneumonia (PCP) in AIDS patients do occur, but no evidence for drug resistance has yet been presented.
To determine whether mutations in the sulfa ...and sulfone drug target are associated with failure of prophylaxis using a sulfa-containing agent.
Portions of the gene for P. carinii dihydropteroate synthase (DHPS), the sulfa and sulfone target, from 27 patients (20 of whom had AIDS) diagnosed with PCP between 1976 and 1997 were amplified using polymerase chain reaction and sequenced. Seven of the 27 patients (all of whom had AIDS) were receiving sulfa or sulfone drugs as prophylaxis for PCP.
Mutations were found at only two amino-acid positions and were significantly more common in patients who received sulfa/sulfone prophylaxis. Mutations were observed in five (71%) out of seven isolates from AIDS patients receiving sulfa/sulfone as prophylaxis compared with only two (15%) out of 13 specimens from AIDS patients who did not (P = 0.022). No mutations were seen in isolates from seven non-HIV-infected patients, none of whom were on prophylaxis. Mutations were only observed in specimens obtained in 1995-1997.
Mutations in two amino-acid positions were significantly more common in AIDS patients with PCP who failed sulfa/sulfone prophylaxis. These amino acids appeared to be directly involved in both substrate and sulfa binding, based on homology to the Escherichia coli DHPS crystal structure. Thus, the results were consistent with the possibility that mutations in the P. carinii DHPS are responsible for some of the failures of sulfa/sulfone prophylaxis in AIDS patients.
: Free clinics are an important part of the US health care safety net and their numbers are rising. This article offers a critical analysis of the politics of free health clinics in Milwaukee, ...Wisconsin. It uses the geographies of resistance literature to assess free clinics as a response to the neoliberalization of health care delivery. It underlines the multiple political spaces free clinics occupy as a result of the entanglements of a diverse range of identities and practices within the clinic space. In Milwaukee, the primary entanglement occurs between the progressive Christian identity inspiring the practices of the free clinic's volunteers and the commodified identity of the corporate non‐profit health care systems that dominate health care delivery in the city. This research suggests that understanding the transition from oppositional identities, such as progressive Christianity, to resistance is an important next step in constructing more robust responses to neoliberal capitalism and other exploitive social relations.
Atovaquone (Mepron, 566c80) is an effective agent against Pneumocystis carinii, which probably acts by binding to cytochrome b and inhibiting electron transport. To assess the possibility that ...atovaquone resistance might be developing, the genes for the cytochrome b from P. carinii sp. f. carinii and P. carinii sp. f. hominis were partially sequenced. Eight of 10 patient isolates had cytochrome b genes with the same amino acid sequence. The P. carinii cytochrome b genes from 2 of 4 patients who had atovaquone prophylaxis failure contained mutations resulting in amino acid changes in one of the ubiquinone (coenzyme Q) binding sites (Qo). These mutations are homologous to mutations in other microorganisms that confer resistance to similar inhibitors. Variations in the sequence of the P. carinii cytochrome b gene suggest but do not prove the development of drug resistance.
This retrospective cohort study was conducted to determine whether Pneumocystis carinii cytochrome b gene mutations in patients with AIDS and P. carinii pneumonia (PCP) are associated with atovaquone ...exposure. Portions of the P. carinii cytochrome b genes that were obtained from 60 patients with AIDS and PCP from 6 medical centers between 1995 and 1999 were amplified and sequenced by using polymerase chain reaction. Fifteen patients with previous atovaquone prophylaxis or treatment exposure were matched with 45 patients with no atovaquone exposure. Cytochrome b coenzyme Q binding site mutations were observed in 33% of isolates from patients exposed to atovaquone, compared with 6% from those who were not (P=.018). There was no difference in survival 1 month after treatment between patients with or without cytochrome b mutations (P=.14). Thus, cytochrome b mutations are significantly more common in patients with AIDS and PCP with atovaquone exposure, but the clinical significance of these mutations remains unknown
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