Ensuring the pathogen safety of intravenous immunoglobulin and other human plasma-derived therapeutic proteins

Countless patients and clinicians rely on therapeutic proteins, such as intravenous immunoglobulins (IVIGs), isolated from human blood plasma. Since plasma is predisposed to contamination by a variety of blood-borne pathogens, ascertaining and ensuring the pathogen safety of plasma-derived therapeutics is a priority among manufacturers. Even though the pathogen safety records for IVIG and other plasma proteins are excellent, the industry remains active in research programs aimed at improving the margin of safety. Industry initiatives designed to increase the safety of plasma-derived products range from donor screening and testing to implementing methods into the manufacturing processes that can inactivate or remove pathogens from product streams. In general, the industry's comprehensive strategy is designed to provide patients and caregivers with the safest plasma products possible.

Lack of pharmacokinetic interaction between rofecoxib and methotrexate in rheumatoid arthritis patients

Rofecoxib is a highly selective and potent inhibitor of cyclooxgenase-2 (COX-2). Methotrexate is a disease-modifying agent with a narrow therapeutic index frequently prescribed for the management of rheumatoid arthritis. The objective of this study was to investigate the influence of clinical doses of rofecoxib on the pharmacokinetics of methotrexate in patients with rheumatoid arthritis. This was a randomized, double-blind, placebo-controlled study in 25 rheumatoid arthritis patients on stable doses of methotrexate. Patients received oral methotrexate (7.5 to 20 mg) on days -1, 7, 14, and 21. Nineteen patients received rofecoxib 12.5, 25, and 50 mg once daily on days 1 to 7, 8 to 14, and 15 to 21, respectively. Six patients received placebo on days 1 to 21 only to maintain a double-blinded design for assessment of adverse experiences. Plasma and urine samples were analyzed for methotrexate and its major although inactive metabolite, 7-hydroxymethotrexate. The AUC(0-infinity) geometric mean ratios (GMR) and their 90% confidence intervals (90% CI) (rofecoxib + methotrexate/methotrexate alone) for day 7/day -1, day 14/day -1, and day 21/day -1, for rofecoxib 12.5, 25, and 50 mg, were 1.03 (0.93, 1.14), 1.02 (0.92, 1.12), and 1.06 (0.96, 1.17), respectively (p > 0.2 for all comparisons to day -1). All AUC(0-infinity), GMR and Cmax GMR 90% CIs fell within the predefined comparability limits of (0.80, 1.25). Similar results were observed for renal clearance of methotrexate and 7-hydroxymethotrexate at the highest dose of rofecoxib tested (50 mg). It was concluded that rofecoxib at doses of 12.5, 25, and 50 mg once daily has no effect on the plasma concentrations or renal clearance (tested at the highest dose of rofecoxib) of methotrexate in rheumatoid arthritis patients.

Transcription patterning of uncoupled proliferation and differentiation in myelodysplastic bone marrow with erythroid-focused arrays

Because abnormal erythroid differentiation is the most common manifestation of the myelodysplastic syndromes (MDS), it was hypothesized that erythroid gene expression may be used to illustrate myelodysplastic transcription patterns. Ten normal bone marrow aspirates (NBM) were first analyzed using an erythroid-focused cDNA array to define steady-state transcription levels. Proliferation and differentiation gene subsets were identified by statistically significant differences between NBM and erythroleukemia gene expression. Next, cDNAs from 5 separate MDS aspirates were studied: refractory anemia, refractory anemia with ringed sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation (RAEB-T), and RAEB-T/secondary MDS. A distinct pattern of significantly increased proliferation-associated and reduced differentiation-associated gene activity was established for MDS.

DNA analysis for the Dombrock polymorphism

BACKGROUND

RBC typing for Do(a) and Do(b) is notoriously difficult, and inaccurate typing can predispose patients to hemolytic transfusion reactions. The DO1/DO2 polymorphism is associated with three nucleotide changes: 378 C>T, 624 T>C and 793 A>G. While the 378 C>T- and 624 T>C-containing codons are silent mutations, the 793 A>G polymorphism in codon 265 encodes asparagine for Do(a) and aspartic acid for Do(b).

STUDY DESIGN AND METHODS

Described here are two PCR-RFLP assays, one using the Mnl I site associated with 624C (DO2) and the other altering two nucleotides within the sense primer, which allows recognition of 793G by the Eam 1105 I.

RESULTS

The assays have been performed on over 100 samples for which the RBC typing of one or both antigens was known. Eight samples had been historically mistyped by hemagglutination.

CONCLUSION

This RFLP assay provides a practical method for typing donor blood for Dombrock alleles.

Contextual influences on the internal structure of phonetic categories: a distinction between lexical status and speaking rate

Previous research has shown that phonetic categories have a graded internal structure that is highly dependent on acoustic-phonetic contextual factors, such as speaking rate; these factors alter not only the location of phonetic category boundaries, but also the location of a category's best exemplars. The purpose of the present investigation, which focused on the voiceless category as specified by voice onset time (VOT), was to determine whether a higher order linguistic contextual factor, lexical status, which is known to alter the location of the voiced-voiceless phonetic category boundary, also alters the location of the best exemplars of the voiceless category. The results indicated that lexical status has a more limited and qualitatively different effect on the category's best exemplars than does the acoustic-phonetic factor of speaking rate. This dissociation is discussed in terms of a production-based account in which perceived best exemplars of a category track contextual variation in speech production.

Perceiving non-native speech

In a series of experiments using monosyllabic words produced by a native and a non-native speaker of English, native English speakers monitored the word-initial consonants of the words to decide which of two consonants was present on each trial. In some of the experiments, a secondary task of a linguistic nature, deciding whether the target-bearing word was a noun or verb, was also required. When the words were presented in silence, the native and non-native stimuli were processed in a like manner. Specifically, when the secondary task was not required, phonemic decisions tended to be made on the basis of prelexical information, whereas when the secondary task was required, they tended to be made on the basis of postlexical information (see Eimas, Marcovitz Hornstein, & Payton, 1990). However, when the listening conditions were degraded by presenting the words at a lower level and in noise, the two types of stimuli yielded different patterns. Native speech was processed as before, whereas for non-native speech phonemic decisions now tended to be made on the basis of postlexical information both when a secondary task was required and when it was not. The contrasting results for native and non-native speech are discussed in terms of models of phoneme processing.

Characterization of viable autofluorescent macrophages among cultured peripheral blood mononuclear cells

BACKGROUND

Inflammatory macrophages that demonstrate intense autofluorescence have been isolated directly from alveolar and peritoneal tissues, but their generation in vitro remains vague. We use flow cytometry to identify a population of autofluorescent macrophages as they arise among nonadherent populations of cultured blood mononuclear cells.

METHODS

Cells were obtained from donated blood buffy coats and placed in culture for 14 days. Unstained populations from the cells remaining in suspension were sampled daily using flow cytometry. During the first 5 culture days, a distinct population of autofluorescent cells arose and comprised an average of < or =14% of the total cell population. This population declined to less than 6% by culture day 8.

RESULTS

The cells were identified as viable macrophages expressing CD68, lysozyme, and HLA-DR. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) demonstrated a unique cytokine profile with IL-1 alpha expression levels 138-fold higher than those measured in uncultured monocytes. No significant elevation in the levels of other cytokines was identified. Upon replating, the sorted populations became readherent, were able to ingest plastic beads, and remained viable for 6 or more additional weeks in culture without evidence of proliferation or multinucleation.

CONCLUSION

Viable autofluorescent macrophage populations arising among cultured peripheral blood may be easily identified and isolated for further study using flow cytometry. Cytometry 44:38-44, 2001. Published 2001 Wiley-Liss, Inc.

Evidence of hypertriglyceridemia in managing HIV patients on efavirenz

Of the recently approved antiretroviral agents, efavirenz has become a popular medication for the treatment of HIV infection. The efficacy of an efavirenz-based regimen has allowed the use of a combination of this medication with other antiretroviral agents in all levels of HIV disease, resulting in decreased viral replication and positive clinical results. Efavirenz is also proposed as an acceptable agent to switch to from a protease inhibitor-based regimen to reduce the risk of metabolic complications. In addition, the favorable side-effect profile, diminished pill burden for clients, and daily dosing have contributed to its popularity. Primary care practitioners should be cognizant of the possible side-effect profile of antiretroviral therapy combinations and enter into a collaborative relationship with the infectious disease clinician to ensure safe and effective patient care.

A direct relationship between the partitioning of the pathogenic prion protein and transmissible spongiform encephalopathy infectivity during the purification of plasma proteins

BACKGROUND

Experimental evidence from rodent models indicates that blood can contain transmissible spongiform encephalopathy (TSE) infectivity, which suggests a potential risk for TSE transmission via proteins isolated from human plasma. Because methods that can reduce TSE infectivity typically are detrimental to protein function, infectivity must be removed to ensure the safety of these therapeutic proteins. Animal bioassays are conventionally used to detect infectivity, but the pathogenic form of the prion protein (PrP(Sc)) can serve as a marker for TSE infectivity.

STUDY DESIGN AND METHODS

Seven plasma protein-purification steps were performed after the plasma intermediates were spiked with TSE-infected material. Resulting fractions were analyzed for PrP(Sc) by using a Western blot assay and for TSE infectivity by using an animal bioassay. Western blots were quantitated by an endpoint dilution analysis, and infectivity titers were calculated by the Spearman-Kärber method.

RESULTS

PrP(Sc) partitioning paralleled TSE infectivity partitioning, regardless of the nature of the protein-purification step. The detection ranges for PrP(Sc) and infectivity were 0 to 5.3 log and 1.1 to 8.9 log median infectious dose per unit, respectively. Clearance of PrP(Sc) and infectivity ranged from 1.0 to 6.0 log.

CONCLUSION

Purification steps for isolating therapeutic proteins from human plasma showed the removal of both PrP(Sc) and TSE infectivity. PrP(Sc) partitioning coincided with infectivity partitioning, which showed a close relationship between PrP(Sc) and TSE infectivity. By exploiting this association, the in vitro Western blot assay for PrP(Sc) was valuable for estimating the partitioning of TSE infectivity during plasma protein purification.

Uncontrolled diabetes mellitus

The conditions of DKA and NKH are life-threatening complications of poorly controlled diabetes mellitus. They have characteristic clinical and laboratory features. If not treated appropriately, they can result in a high mortality rate of 15% to 28% in DKA and 17% to 50% in NKH.

Human erythroid porphobilinogen deaminase exists in 2 splice variants

Human porphobilinogen deaminase (PBGD) is, reportedly, encoded by 2 distinct messenger RNAs (mRNAs) transcribing from a single gene. The ubiquitous form of the PBGD gene product is often used as an endogenous reference in gene expression studies because it is pseudogene free and has minimal transcriptional variability among tissues. A distinct erythroid-specific gene product has also been described because of the alternate splicing of the gene. Here is reported the existence of an additional erythroid-specific isoform of PBGD mRNA in primary cells.

Metastatic paraganglionoma presenting as a scalp nodule

Malignant neoplasms with neural differentiation uncommonly present as cutaneous masses. However, a rapidly growing skin lesion in patients with a past history of retroperitoneal soft tissue tumors suggests that dissemination of that lesion may be taking place.

Infusible platelet membranes retain partial functionality of the platelet GPIb/IX/V receptor complex

Infusible platelet membranes (IPMs) prepared from fresh or outdated human platelets have been shown to correct prolonged bleeding times in thrombocytopenic rabbits. In previous trials, IPMs did not seem to be immunogenic and lacked dose-limiting toxicity. The present study was undertaken to explore whether the platelet glycoprotein (GP) Ib/IX/V complex might retain functionality in the IPM preparation. IPMs did not spontaneously bind von Willebrand factor (vWF), but saturable binding could be induced by ristocetin, with a dissociation constant (Kd) of 0.31 +/- 0.03 microgram/mL at 1.0 mg/mL of ristocetin. Of 4 anti-GPIb-alpha monoclonal antibodies tested, AN-51 inhibited vWF binding 67.8% +/- 5.8%, whereas AS-2, AS-7, and SZ-2 were ineffective. Maximal vWF binding induced by botrocetin was only 10% to 15% of that observed with ristocetin. Retention of partial functionality of the GPIb/IX/V receptor allowing vWF binding in a modulated manner seems to represent a critical mechanism by which IPMs may provide hemostatic efficacy.

Tolerance towards explosives, and explosives removal from groundwater in treatment wetland mesocosms

A short-term study was performed to determine the feasibility of using constructed wetlands to remove explosives from groundwater, and to assess accumulation of parent explosives compounds and their known degradation compounds in wetland plants. Tolerance towards explosives in submersed and emergent plants was screened over a range of 0 to 40 mg L(-1). Tolerance varied per compound, with TNT evoking the highest, 2NT the lowest, and 24DNT, 26DNT, and RDX an intermediate growth reducing effect. Submersed plants were more sensitive to TNT than emergent ones. A small-scale 4-month field study was carried out at the Volunteer Army Ammunition Plant, Chattanooga, TN. In this surface-flow, modular system, the influent contained high levels (>2.1 mg L(-1)) of TNT, 2,4DNT, 2,6DNT, 2NT, 3NT, and 4NT, and the HRT was 7 days. The performance criteria of US EPA treatment goals for local discharge of 2,4DNT concentration <0.32 mg L(-1), and 26DNT concentration <0.55 mg L(-1) were not met at the end of the experiment, although explosives levels were greatly reduced. Low levels of 2ADNT and 4ADNT were transiently observed in the plant biomass. Results of two other, older, constructed wetlands, however, indicated that in these systems treatment goals were met most of the time, residues of explosives parent compounds and known degradation compounds in plant tissues were low and/or transient, and in substrates were low.

Effect of WEB 2086 on leukocyte adherence in response to hemorrhagic shock in rats

BACKGROUND

The pathogenesis of generalized microvascular injury after hemorrhagic shock is known to involve the generation of platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine [PAF]). The release of PAF is manifested in several ways, including by increased vascular permeability, altered vascular reactivity, and increased leukocyte adherence to the endothelium. WEB 2086 is a PAF antagonist that has been shown experimentally to improve survival after hemorrhagic shock. The purpose of this study was to examine the efficacy of WEB 2086 in attenuating leukocyte adherence before, during, and after hemorrhagic shock.

METHODS

After a control period, blood was withdrawn to reduce the mean arterial pressure to 40 mm Hg for 30 minutes in urethane-anesthetized rats. Mesenteric venules in a transilluminated segment of the small bowel were examined to quantitate leukocyte adherence using intravital microscopy.

RESULTS

In sham-operated rats (control), there was minimal to no leukocyte adherence throughout the experiment. Hemorrhagic shock resulted in a significant increase in leukocyte adherence postshock during resuscitation (10.9 +/- 1.8 cells/100 microm, p < 0.01) when compared with controls. WEB 2086, when given before shock, significantly attenuated leukocyte adherence (0.1 +/- 0.08 cells/100 microm, p < 0.01) when compared with hemorrhagic shock alone. This effect of WEB 2086 on adherence could be demonstrated even when it was given during (3.5 +/- 0.9 cells/100 microm, p < 0.01) and 10 minutes into (5.8 +/- 1.1 cells/100 microm, p < 0.05) hemorrhagic shock.

CONCLUSION

Our findings suggest that WEB 2086 may be of therapeutic benefit against the microvascular damage sustained after hemorrhagic shock.

NADH-dependent reduction of sulphamethoxazole hydroxylamine in dog and human liver microsomes

1. Reduction of hydroxylamine drug metabolites by NADH-dependent hydroxylamine reductase (NDHR) has been suggested to be involved in the pathogenesis of idiosyncratic sulphonamide toxicity in humans. The dog represents a naturally occurring clinical model for sulphonamide toxicity in humans. he purpose of these studies, therefore, was to characterize the presence of hepatic NADH-dependent hydroxylamine reductase activity in the dog and to compare this activity with that found in humans. 2. NDHR activity was characterized by the presence of two enzymes in both dog and human liver microsomes, with comparable estimates of Km (Km1 = 75 microM, Km2 = 404 microM in dog; Km1 = 69 microM, Km2 = 503 microM in human). Estimates of maximal velocity were significantly, but not dramatically, higher for dog NDHR (Vmax1 = 2.09 nmole mg(-1) min(-1) Vmax2 = 4.58 nmole mg(-1) min(-1) compared with human NDHR (Vmax1 = 0.42 nmole mg(-1) min(-1), Vmax2 = 1.56 nmole mg(-1) min(-1)). NDHR in dog, as in humans, preferred NADH to NADPH, was more active at pH 6.3 than at 7.4 and was not inhibited by carbon monoxide, azide, anaerobic conditions, the CYP substrate inhibitors tolbutamide, dextromethorphan, or erythromycin, or antibodies directed against CYP2C, CYP2D or CYP3A. 3. It is concluded that two forms of NDHR are present in dog and humans with similar biochemical characteristics. Although NDHR activity has been attributed to a CYP2D isoform in pig, there is no evidence for involvement of CYP450 in the reduction of sulphamethoxazole hydroxylamine in either dogs or humans.

Post-traumatic stress disorder in primary care practice

PURPOSE

To provide clinicians in primary care settings with guidelines on evaluation, diagnosis, and management of post-traumatic stress disorder (PTSD).

DATA SOURCES

Research-based articles in the medical and psychiatric literature, review articles, and diagnostic criteria.

CONCLUSIONS

PTSD is a disorder where psychological and physiological reactions are closely related. Populations at risk include survivors of motor vehicle accidents, natural and man-made disasters, torture, and childhood sexual abuse, as well as combat veterans.

IMPLICATIONS FOR PRACTICE

Patients with a history of recent trauma should be targeted for early screening and intervention. Effective treatment of PTSD is a three-stage process consisting of stabilization of symptoms, processing of traumatic perceptions, and integration of trauma into the patient's world- and self-view.