Osteogenic protein-1 (bone morphogenetic protein-7) reduces severity of injury after ischemic acute renal failure in rat

We have shown that osteogenic protein-1 (OP-1) (bone morphogenetic protein-7) is responsible for the induction of nephrogenic mesenchyme during embryonic kidney development. Gene knock-out studies showed that OP-1 null mutant mice die of renal failure within the first day of postnatal life. In the present study, we evaluated the effect of recombinant human OP-1 for the treatment of acute renal failure after 60 min bilateral renal artery occlusion in rats. Bioavailability studies in normal rats indicate that approximately 1.4 microg OP-1/ml is available in the circulation 1 min after intravenous administration of 250 microg/kg, which then declines steadily with a half life of 30 min. About 0.5% of the administered OP-1 dose/g tissue is targeted for OP-1 receptors in the kidney. We show that OP-1 preserves kidney function, as determined by reduced blood urea nitrogen and serum creatinine, and increased survival rate when administered 10 min before or 1 or 16 h after ischemia, and then at 24-h intervals up to 72 h after reperfusion. Histochemical and molecular analyses demonstrate that OP-1: (a) minimizes infarction and cell necrosis, and decreases the number of plugged tubules; (b) suppresses inflammation by downregulating the expression of intercellular adhesive molecule, and prevents the accumulation and activity of neutrophils; (c) maintains the expression of the vascular smooth muscle cell phenotype in pericellular capillaries; and (d) reduces programmed cell death during the recovery. Collectively, these data suggest that OP-1 prevents the loss of kidney function associated with ischemic injury and may provide a basis for the treatment of acute renal failure.

Effect of fiber length on glass microfiber cytotoxicity

Fiber length has been implicated as a determinant of fiber toxicity. Fibers of narrowly defined length can be generated by dielectrophoretic classifiers. Since the quantities of fibers produced are very small, we developed a rat alveolar macrophage microculture system to study the toxicity of these samples. The objective of this study was to examine the role of fiber length on the cytotoxicity of Manville code 100 (JM-100) fibers. Rat alveolar macrophages were cultured with 0-500 microg/ml of 5 lengths of JM-100 fibers on 96-well plates. After 18 h, well supernatants were removed and lactate dehydrogenase (LDH) activity was measured to assess cell damage. Chemiluminescence (CL), an assessment of macrophage function, was measured by adding lucigenin with or without zymosan, a particulate stimulus, to appropriate wells. For each fiber length the effects were concentration dependent: CL declined and LDH rose with increasing fiber concentration. Comparing the effects of different lengths showed the greatest toxicity from a relatively long fiber sample (mean length = 17 microm). Microscopic examination of the interaction of fibers with macrophages revealed multiple macrophages attached along the length of the long fibers. This suggests that frustrated, or incomplete, phagocytosis may be a factor in the increased toxicity of longer fibers. Overall the results demonstrate that length is an important determinant of toxicity for JM-100 fibers.

Effects of a smoking cessation program for pregnant women and their partners attending a public hospital antenatal clinic

This study aimed to assess the effect of a hospital-based smoking cessation intervention delivered by midwives during routine antenatal and postnatal care on the smoking habits of pregnant women and their partners. At the first antenatal visit, women in the intervention group (n = 110) were given a demonstration of the immediate effects of smoking on foetal heart rate, brief smoking cessation advice and smoking cessation booklets for themselves and their partners; at delivery, they were given brief advice and a booklet about postpartum cessation. Compared with an historical control group who received usual care (n = 110) and assuming those lost to follow-up continued to smoke, biochemically-verified maternal cessation sustained from at least 24 weeks gestation to late pregnancy was 6.4% in the intervention group and 1.8% in the comparison group. However, there was no difference between maternal quit rates at six months postpartum. Partners were more likely to try to quit in the intervention group, but quit rates did not differ. Exposure to the intervention was not associated with increased levels of psychological distress, as measured by the 12-item General Health Questionnaire. We conclude that this type of intervention, when implemented by staff during routine care, is probably associated with a small improvement in maternal cessation in pregnancy, similar to that produced by minimal advice to quit smoking.

Incidence and significance of neutralizing antibodies to interferon beta-1a in multiple sclerosis. Multiple Sclerosis Collaborative Research Group (MSCRG)

BACKGROUND

Interferon beta is an effective treatment for relapsing multiple sclerosis (MS). As with other protein drugs, neutralizing antibodies (NAB) can develop that reduce the effectiveness of treatment.

OBJECTIVES

To determine the incidence and biological significance of NAB to interferon beta-la (IFN-beta-1a; Avonex; Biogen, Cambridge, MA) in MS patients.

METHODS

A two-step assay for NAB to IFN-beta-1a was developed and used to assay serum samples from participants in the phase III clinical trial of IFN-beta-1a, and from patients in an ongoing open-label study of IFN-beta-1a. The biological significance of NAB to IFN-beta-1a was determined by relating the NAB assay result to in vivo induction of the IFN-inducible molecules neopterin and beta-2 microglobulin, and the clinical significance was determined by comparing clinical and MRI measures of disease activity after 2 years of IFN-beta-1a therapy in patients who were NAB+ and NAB-. The incidence of NAB was compared in MS patients who had used only IFN-beta-1a with the incidence in MS patients who had used only IFN-beta-1b.

RESULTS

In patients in the open-label study, development of NAB to IFN-beta-1a resulted in a titer-dependent reduction in neopterin induction after interferon injections. In patients in the phase III study, development of NAB was associated with a reduction in beta-2 microglobulin induction. In the phase III study, a trend toward reduced benefit of IFN-beta-1a on MRI activity in NAB+ versus NAB- patients was observed. The incidence of NAB to IFN-beta-1a in the open-label study was approximately 5% over 24 months of treatment of IFN-beta-1a therapy, but was four- to sixfold higher using the same assay for patients exposed only to IFN-beta-1b for a similar duration. There were no clinical, MRI, or CSF characteristics that were predictive of which patients would develop NAB.

CONCLUSIONS

NAB directed against IFN-beta have in vivo biological consequences in patients with MS. The frequency with which MS patients develop NAB against IFN-beta is significantly greater with IFN-beta-1b therapy compared with IFN-beta-1a therapy. Treatment decisions in MS patients treated with IFN-beta should take into account development of NAB.

Structural and functional differences between glycosylated and non-glycosylated forms of human interferon-beta (IFN-beta)

PURPOSE

Two recombinant IFN-beta products have been approved for the treatment of multiple sclerosis, a glycosylated form with the predicted natural amino acid sequence (IFN-beta-1a) and a non-glycosylated form that has a Met-1 deletion and a Cys-17 to Ser mutation (IFN-beta-1b). The structural basis for activity differences between IFN-beta-1a and IFN-beta-1b, is determined.

METHODS

In vitro antiviral, antiproliferative and immunomodulatory assays were used to directly compare the two IFN-beta products. Size exclusion chromatography (SEC), SDS-PAGE, thermal denaturation, and X-ray crystallography were used to examine structural differences.

RESULTS

IFN-beta-1a was 10 times more active than IFN-beta-1b with specific activities in a standard antiviral assay of 20 x 10(7) IU/mg for IFN-beta-1a and 2 x 10(7) IU/mg for IFN-beta-1b. Of the known structural differences between IFN-beta-1a and IFN-beta-1b, only glycosylation affected in vitro activity. Deglycosylation of IFN-beta-1a produced a decrease in total activity that was primarily caused by the formation of an insoluble disulfide-linked IFN precipitate. Deglycosylation also resulted in an increased sensitivity to thermal denaturation. SEC data for IFN-beta-1b revealed large, soluble aggregates that had reduced antiviral activity (approximated at 0.7 x 10(7) IU/mg). Crystallographic data for IFN-beta-1a revealed that the glycan formed H-bonds with the peptide backbone and shielded an uncharged surface from solvent exposure.

CONCLUSIONS

Together these results suggest that the greater biological activity of IFN-beta-1a is due to a stabilizing effect of the carbohydrate on structure.

Prognosis of patients treated with whole-brain radiation therapy for metastatic gestational trophoblastic disease

We evaluated the effect of multiple treatment- and disease-related variables on the outcome of patients receiving whole-brain radiation therapy (WBRT) for metastatic gestational trophoblastic disease (GTD). Between November 1967 and December 1994, 21 patients were treated at our institution for GTD metastatic to the brain. All received WBRT, of median 2200 cGy (range 200-3600 cGy). Median follow-up, from date of diagnosis of brain metastases, was 77 months (range 11-170 months). The 5-year actuarial local control of initial brain metastases with > or = 2200 cGy was 91%, compared to 24% with < 2200 cGy (P = 0.05). The 2- and 5-year actuarial survivals of the 9 patients whose disease was controlled at extracranial sites were 100 and 83%, respectively, compared to 8 and 0%, respectively, for the 12 whose extracranial disease was not controlled (P = 0.0002). Four (33%) of the patients with persistent or progressive extracranial disease later developed new sites of brain metastases, compared to 0% of the patients whose extracranial disease was controlled (P = 0.05). Eleven patients progressed at their initial site(s) of brain metastasis or developed new intracranial lesions; 6 of them died of brain metastases. Survival of patients with GTD metastatic to the brain is excellent if extracranial disease can be controlled. The total dose of radiation is critical in achieving control of initial brain metastases. Patients with uncontrolled extracranial disease are more likely to develop new brain metastases. Salvage of intracranial failures after WBRT is rare.

Impaired bioavailability of interferon beta-1a when administered intramuscularly by needle-free injection

Intramuscular (IM) or subcutaneous (SC) drug administration of small molecules and protein has been demonstrated by use of needle-free jet injection methods. One device that achieves needle-free parenteral administration, BIOJECTOR, is commercially available and was evaluated for IM delivery of interferon beta-1a. Recombinant human interferon beta-1a (IFN beta-1a) is a glycosylated protein containing 166 amino acids and has a molecular weight of 22.5 kDa. Needle-free jet injection of IFN beta-1a with the BIOJECTOR was assessed in a human Phase I trial. The study was a randomized, open-label crossover in which 12 healthy subjects each received 60 microg of IFN beta-1a as an IM injection by standard needle administration and by needle-free jet injection. Blood samples for pharmacokinetic (serum activity, PK) and pharmacodynamic (serum neopterin, PD) determinations were collected through 144 hours post-dose. Mean serum antiviral activity AUC values for needle-free and standard needle injection were 218 and 531 U x h/ml, respectively; corresponding C(max) values were 19.7 and 29.0 U/ml. Median T(max) following both treatments was 12 hours. The relative bioavailability of IFN beta-1a, needle-free to standard needle injection, was 41.1% with 90% confidence limits of 24.4% to 69.3%. Mean serum neopterin E(AUC) values for needle-free and standard needle injection were 114 and 325 ng x h/mL, respectively; corresponding E(max) values were 2.3 and 5.6 ng/mL. The ratio of serum neopterin E(AUC), needle-free to standard needle, was 34.9% with 90% confidence limits of 23.4% to 52.1%. Injection site reactions were substantially more frequent following needle-free injection; however, systemic side effects were less frequent. Intramuscular needle-free jet injection and needle-based injection of a 22.5-kDa glycoprotein do not produce equivalent systemic PK or PD responses.

Medication side effects in anxious patients: negative placebo responses?

The purpose of the present study was to detect any problems among anxious patients in switching from alprazolam to extended release alprazolam. Fifty-four patients with an anxiety disorder, stabilized on alprazolam, entered the study. During the first 2 weeks, all patients took alprazolam as usual. During the second 2 weeks, they all took the same dosage of the extended release formulation. They were evaluated weekly with standard clinical measures and were asked to report any adverse medical events. The clinical measures showed modest, steady improvement over the course of the study. Patients reporting adverse medical events increased from 26% of the sample to 60% after the switch of dosage forms. Most of these events were anxiety-like (48%) or sedative (37%). Patients who developed sedative events took slightly higher mean doses of alprazolam. Patients who developed anxiety-like events had higher baseline scores on the Somatization, Anxiety and Phobia clusters of the SCL-90. The results suggest that more anxious patients confronted with a change of regimen commonly generate anxiety symptoms that they attribute to the medication, i.e., negative placebo responses, perhaps especially if they have a tendency toward somatization. A study designed to sort out pharmacological and psychological effects and further explore the mechanisms at work is indicated.

Expression and analysis of coronafacate ligase, a thermoregulated gene required for production of the phytotoxin coronatine in Pseudomonas syringae

Coronafacic acid, the polyketide component of the phytotoxin coronatine, is activated and coupled to coronamic acid via amide bond formation, a biosynthetic step presumably catalyzed by the coronafacate ligase (cfl) gene product. In the present study, cfl was fused to the carboxy terminus of malE, which encodes the maltose-binding protein (MBP), and overexpressed in Escherichia coli. Immunoblot analysis indicated that Cfl contained an ATP-binding region, a motif conserved in enzymes which activate their substrates by adenylation. MBP-Cfl was overproduced and purified from Pseudomonas syringae and the protein fusion was used to generate antisera. Anti-MBP-Cfl antibodies and a transcriptional fusion of the cfl promoter to a promoterless glucuronidase gene were used to follow the temporal expression of coronafacate ligase. The results indicated that transcription of cfl is temperature-sensitive. Furthermore, a nonpolar mutation in cfl suggested that the gene may have a role in coronafacic acid biosynthesis.

The ABC of committee work 2: How meetings are conducted

The first part of this article looked at the roles of the officers in a committee. This second part illustrates for nurses how committee meetings should be conducted. Rules govern the way meetings are announced and who may be present. The opening and closing of meetings need to be properly defined and conducted. Most committee meetings adopt the same agenda format. General conduct and the order of business are equally universal but latitude is exercised in less formal committees. Awareness of proper committee procedures makes it much more comfortable and satisfying to participate in meetings.

The ABC of committee work. 1: Officers, members and their duties

Many nurses will be asked during their career to serve on a committee but will have little concept of the work and procedures involved. This article, the first of two parts, describes the work of the officers and members of a committee. The chairperson controls meetings according to rules which make for the smooth and equitable running of the committee. The secretary, who has to work closely with the chairperson, is often more experienced regarding the rules and can do valuable work in guiding the chairperson. Normally, the secretary's job includes duties before, during and after meetings. A treasurer looks after the financial affairs of any committee which holds a budget. The vice-chairperson is the natural successor of the chairperson and should be groomed to take the chair.

Comparison of inducible nitric oxide synthase gene expression and lung inflammation following intratracheal instillation of silica, coal, carbonyl iron, or titanium dioxide in rats

The pulmonary toxicity of the respirable dusts silica, coal, carbonyl iron, and titanium dioxide on alveolar macrophage (AM) and neutrophil (PMN) inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production was investigated. Rats were intratracheally instilled with 5 mg/100 g body weight of silica, coal, carbonyl iron, or titanium dioxide. The dust particles averaged less than 5 microns in diameter. Bronchoalveolar lavage was performed 24 h later. Bronchoalveolar lavage cell (BALC) differentials, iNOS gene expression and NO production by BALC (measured indirectly as NO-dependent chemiluminescence), and lavageable lung protein levels were measured. Analyzed on an equal mass basis, silica, coal, and titanium dioxide dusts increased the production of iNOS-dependent NO by AM. Silica and titanium dioxide both increased the levels of iNOS mRNA while carbonyl iron and coal did not. Each dust caused an increase in PMN, indicating an inflammatory response. Carbonyl iron and titanium dioxide decreased the numbers of AM. Levels of acellular lavageable lung protein were increased by silica, carbonyl iron, and titanium dioxide. When exposure was normalized for an equal number of particles, the pneumotoxic dusts, silica and coal, caused more inflammation and NO production than the nuisance dusts, carbonyl iron and titanium dioxide. Therefore, it appears that particle number is a more appropriate metric of exposure than mass when comparing the relative pathogenicity of dusts of different sizes. Furthermore, since the potency of these dusts (on a particle number basis) to increase iNOS gene expression reflects their inflammatory and pathogenic potential, it is proposed that NO may contribute to the early inflammatory damage observed in the lung following dust exposure.

Measurement variability in upper extremity posture among VDT users

Hand and arm posture while keying is frequently mentioned as a risk factor for upper extremity musculoskeletal disorders (UEMSDs) among video display terminal (VDT) operators. However, many epidemiologic studies have not included measures of posture of VDT operators, in part, because of the difficulty of assessing posture rapidly and reliably among large numbers of subjects. For a single measure of posture to be useful for estimating dose-response relationships between posture and risk of UEMSDs, the within-subject variability of the postural measure must be smaller than the between-subject variability of the postural measure. In addition, the measure must be stable over time. We estimate the ratio of between- to within-subject variability for manual goniometry by measuring six postural angles on six occasions among 19 subjects using VDTs. For each postural angle, between-subject variability was substantially and statistically significantly larger than within-subject variability. Stability of postural measures over time was sufficient to justify a single postural measurement in epidemiologic studies. We conclude that manual goniometry can provide useful information about upper extremity posture among VDT users for use in epidemiologic studies of UEMSDs.

Colonization and disinfection of biofilms hosting coliform-colonized carbon fines

The documented release of carbon fines from granular activated carbon filters is a concern for drinking water utilities, since these particles may carry coliform and even pathogenic bacteria through the disinfection barrier. Such a breakthrough could have an impact on distribution system biofilms. Using total cell counts, specific monoclonal antibody staining, and computerized image analysis, we monitored the colonization of introduced Klebsiella pneumoniae associated with carbon fines in mixed-population biofilms. The particles transported the coliforms to the biofilms and allowed successful colonization. Chlorine (0.5 mg/liter) was then applied as a disinfectant. Most K. pneumoniae along with the carbon fines left the biofilm under these conditions. The impact of chlorine was greater on the coliform bacteria and carbon fines than on the general fixed bacterial population. However, 10% of the introduced coliforms and 20% of the fines remained in the biofilm. The possibility that this represents a mechanism for bacteria of public health concern to be involved in regrowth events is discussed.

In vitro effects of large and small glass fibers on rat alveolar macrophages

The objective of this study was to explore the use of alveolar macrophage culture to evaluate the cytotoxicity of two glass fiber materials, a building insulation fiberglass (a relatively long and thick fiber) and a glass microfiber (a short and thin fiber). Alveolar macrophages were obtained from male Sprague-Dawley rats by bronchoalveolar lavage and were cultured with varying fiber concentrations for up to 3 d. Fiber toxicity was assessed by assaying cell viability, membrane integrity, and phagocyte function. The microfibers exhibited a concentration-dependent cytotoxicity shown by the loss of cell viability and function. The building insulation fiberglass had little effect on cell viability and did not change macrophage function in this assay system. The results of this study show that short and thin glass fibers are more toxic than long and thick fibers in vitro, supporting a role of fiber dimension in toxicity.