Erectile function, erection hardness and tolerability in men treated with sildenafil 100 mg vs. 50 mg for erectile dysfunction.

AIM: To compare efficacy and tolerability between 100-mg and 50-mg sildenafil doses in five double-blind, placebo-controlled (DBPC) fixed-dose studies. METHODS: Doses were compared for the change (baseline to end of 8-12 weeks of DBPC treatment) in score on the Erectile Function (EF) domain of the International Index of Erectile Function (IIEF; from five fixed-dose studies, > 1500 men); the per-patient estimated percentage of occasions that a specified Erection Hardness Score (EHS; from two of the five fixed-dose studies, > 500 men) was achieved, computed from logistic regression; the odds ratio (OR) of achieving EHS3 (hard enough for penetration, but not completely hard) and EHS4 (fully hard and completely rigid); and the adverse event incidence by treatment (from all five fixed-dose studies). RESULTS: For the 100-mg vs. 50-mg dose, IIEF-EF score improvement was consistently greater across the five studies and was statistically significant when data from two studies with similar design were pooled (10.7 ± 0.64 vs. 8.9 ± 0.83, p = 0.0287); and during the first 2 weeks of treatment, the odds of achieving EHS4 erections were almost doubled in one study (OR = 1.77, p = 0.0398). Sildenafil was generally well tolerated at either dose. CONCLUSION: Men with erectile dysfunction treated with 100-mg compared with 50-mg sildenafil may be more likely to achieve a greater improvement in erectile function and, within the first 2 weeks, completely hard and fully rigid erections, with little or no greater risk to tolerability.

Gamma globulin and antibody formation in vitro. VII. Effect of x-irradiation on the secondary antibody response in vitro.

The present studies have shown that the influence of X-irradiation on the secondary antibody response in vitro is remarkably similar to its effect on the primary response in vivo. When sensitized tissue was first irradiated and then reexposed to antigen, the duration of the interval between irradiation and antigen addition determined the degree of inhibition of the secondary response obtained. A delay of 12 hr resulted in stronger inhibition than a delay of 6 hr, and an interval of 24 hr before reexposure to antigen caused complete suppression of antibody production to diphtheria toxoid and almost complete suppression when sheep RBC were used as the antigen. Induction of the secondary response in rabbit lymph node tissue in vitro followed by exposure to X-irradiation, revealed that immediate exposure to irradiation after antigen produced stronger inhibition of the subsequent response than irradiation on days 2-3. Irradiation on day 6 had no detectable effect. The effectiveness of the early radiation is probably due to prevention of the proliferation of the antibody-forming cells. BUDR was found to be effective at similar time periods as X-irradiation, whereas colchicine could still stop antibody formation when added late during the secondary response in vitro. It was noted that lymph nodes from some BSA-sensitized rabbits as late as 18 months after sensitization gave a response indistinguishable from a typical secondary response, even when not reexposed to antigen.

Counterfeit phosphodiesterase type 5 inhibitors pose significant safety risks.

Counterfeit drugs are inherently dangerous and a growing problem; counterfeiters are becoming increasingly sophisticated. Growth of the counterfeit medication market is attributable in part to phosphodiesterase type 5 inhibitor (PDE5i) medications for erectile dysfunction (ED). Millions of counterfeit PDE5is are seized yearly and account for the bulk of all counterfeit pharmaceutical product seizures. It has been estimated that up to 2.5 million men in Europe are exposed to illicit sildenafil, suggesting that there may be as many illegal as legal users of sildenafil. Analysis of the contents of counterfeit PDE5is shows inconsistent doses of active pharmaceutical ingredients (from 0% to > 200% of labelled dose), contaminants (including talcum powder, commercial paint and printer ink) and alternative ingredients that are potentially hazardous. In one analysis, only 10.1% of samples were within 10% of the labelled tablet strength. Estimates place the proportion of counterfeit medications sold over the Internet from 44% to 90%. Of men who purchase prescription-only medication for ED without a prescription, 67% do so using the Internet. Counterfeit PDE5is pose direct and indirect risks to health, including circumvention of the healthcare system. More than 30% of men reported no healthcare interaction when purchasing ED medications. Because > 65% actually had ED, these men missed an opportunity for evaluation of comorbidities (e.g. diabetes and hypertension). Globally, increased obstacles for counterfeiters are necessary to combat pharmaceutical counterfeiting, including fines and penalties. The worldwide nature of the counterfeit problem requires proper coordination between countries to ensure adequate enforcement. Locally, physicians who treat ED need to inform patients of the dangers of ordering PDE5is via the Internet.

Correlations between increased erection hardness and improvements in emotional well-being and satisfaction outcomes in men treated with sildenafil citrate for erectile dysfunction.

To explore relationships between erection hardness and other outcomes in men with erectile dysfunction (ED). Pooled analyses were conducted on 27 randomized, double-blind, placebo-controlled trials and six open-label trials from the worldwide sildenafil database. Outcomes included erection hardness graded subjectively, hardness and sexual satisfaction questions from the International Index of Erectile Function, general and sexually-specific emotional well-being from the self-esteem and relationship questionnaire, and the erectile dysfunction inventory of treatment satisfaction. Hardness outcomes improved (with a possible dose-response relationship for the achievement of fully hard and rigid erections) and correlated positively with the other outcomes. Sildenafil 100 mg produced optimal erection hardness (fully hard and rigid erections) in a substantial proportion of men with ED. Because optimal erection hardness correlated positively with some emotional well-being and satisfaction outcomes, sildenafil 100 mg may be the most appropriate dosage for treatment of ED for most men.

In vivo chemotaxis of rat leukocytes in the presence of circulating chylomicrons.

Dietary-induced chylomicronemia was produced in rats to determine its effect on the chemotactic activity of 51Cr-labelled adoptively transferred isologous leukocytes. Rats fed a low protein high fat diet for 2 months had normal total plasma cholesterol and triglyceride levels, but increased amounts of chylomicrons. Circulating neutrophils and monocytes from animals on a normal diet were able to phagocytose chylomicrons from plasma of those animals on the special diet. Peritoneal exudate cells from the latter animals contained intracellular chylomicrons demonstratable both histologically and biochemically. Neutrophils and mononuclear cells from normal or special fed animals, when transferred to chylomicronemic recipients, had a reduced ability to accumulate at the site of a complement-dependent inflammatory reaction but circulated normally. The defective chemotactic activity observed could be duplicated when cells were allowed to ingest aggregated protein instead of chylomicrons. It was concluded that circulating leukocytes ingest chylomicrons from the plasma with a resultant reduction in their chemotactic activity. The results were discussed in relation to the increased incidence of infection in diabetes characterized by Type I and V hyperlipidemias. It was also suggested that phagocytosis of particulate substances by entrapped leukocytes in atherosclerotic lesions would induce phagocytic enzyme release which could contribute to the eventual destruction of the vascular wall.

Cholesterol-lowering effect of hydroxychloroquine in patients with rheumatic disease: reversal of deleterious effects of steroids on lipids.

PURPOSE: The effects of hydroxychloroquine (HCQ) on serum levels of cholesterol, triglycerides, and high- (HDL) and low-density lipoprotein (LDL) were studied in patients with rheumatoid arthritis or systemic lupus erythematosus. PATIENTS AND METHODS: A total of 155 women were divided into the following treatment groups: Group A: patients taking HCQ and no steroids (n = 58); Group B: patients taking steroids and no HCQ (n = 35); Group C: patients receiving both HCQ and steroids (n = 18); and Group D: patients receiving neither HCQ nor steroids (n = 44). RESULTS: HCQ therapy had a high statistical association with low serum levels of cholesterol (181 mg/dL; p = 0.0006), triglycerides (106 mg/dL; p = 0.0459), and LDL (101 mg/dL; p = 0.0004), irrespective of concomitant steroid administration. The HCQ-treated group (A) had lower cholesterol (181 mg/dL; p = 0.0039) and LDL (101 mg/dL; p = 0.007) levels than those receiving neither HCQ nor steroids (205 mg/dL) and 128 mg/dL) (Group D). No HDL differences were observed. CONCLUSION: The effects of HCQ do not appear to be due to changes in diet or weight, and the drug was well tolerated. Although the mechanism of cholesterol lowering by HCQ is not known, this drug deserves further investigation for its lipid-lowering properties.

Inhibition of human immunodeficiency virus type 1 replication by hydroxychloroquine in T cells and monocytes.

Chloroquine and its analogue hydroxychloroquine (HCQ) have been shown to inhibit a variety of viral infections including influenza and adenovirus through blockade of viral entry via inhibition of endosomal acidification. We have extended these observations to human immunodeficiency virus type 1 (HIV-1) infection utilizing primary T cells and monocytes, a T cell line (CEM), and a monocytic cell line (U-937). HCQ inhibited HIV-1 replication (> 75%), as measured by reverse transcriptase activity, in the primary T cells and monocytes as well as the T cell and monocytic cell lines. HCQ itself had no anti-reverse transcriptase activity and was not toxic to the cells at concentrations inhibitory to viral replication. Intracytoplasmic staining with an anti-p24 antibody, 24 h after infection, revealed the presence of intracytoplasmic virus, suggesting that the drug does not block viral entry. The production of steady-state HIV-1 mRNA was not affected by HCQ in that comparable levels of HIV-1 mRNA could be detected by Northern blot analysis and by in situ hybridization in both the HCQ-treated and untreated cells. However, HCQ does appear to affect production of infectious HIV-1 virions because viral isolates from HCQ-treated cells could not infect target CEM cells. These data suggest that HCQ may be useful adjunctive therapy in the treatment of HIV-1 infection.

The chemotaxis of selected cell types to connective tissue degradation products.

Because rheumatoid inflammation is associated with the presence of large numbers of leukocytes in joint effusions, the question of whether enzymatic splitting of collagen and fibrin can lead to generation of chemotactic factors was investigated. Fibrinogen was purified from the plasma of four different species, and the homogeneity of the preparations was established by physicochemical and immunologic techniques. Fibrin was prepared and then lysed with plasmin to obtain fibrin degradation products (FDP). Similarly, purified collagenase was used to lyse collagen in vitro, and the chemotactic activity of the reaction mixtures was analyzed. The experiments presented indicate that fibrinogen, fibrin, and plasmin do not possess any intrinsic chemotactic activity. However, when fibrin was split by plasmin, FDP of human, bovine, sheep, and equine origin all proved to be strong leukotactic agents for polymorphonuclear leukocytes (PMN). Purified collagenase per se was found to be a cell type-specific chemotactic agent for PMN. Not only were collagen degradation products not chemotactic, but they also inhibited the leukotactic activity of the purified collagenase. Furthermore, this inhibition of the chemotactic activity of collagenase was independent of its enzymatic activity. The results presented suggest that there is a direct correlation between the process of fibrinolysis and the chemotactic attraction of leukocytes and between the presence of collagenase and leukotaxis. This system may serve as a model to explain the mechanisms by which cells accumulate in inflamed joints.

Physiologic and pharmacologic alterations of rat leukocyte chemotaxis (Cx) in vivo.

The method of adoptively transferring 51Cr-labeled rat leukocytes iv to isologous recipients was used to quantitate the extravascular accumulation of specific cell types at the site of inflammation induced by local injection of various phlogistic agents. Experiments were designed to determine whether cellular accumulation could be modified at the level of the chemotactic factor, by serum components, or by alteration of the responding cell itself. The results indicated a selective attraction of mononuclear cells to the local injection site of BCG and of neutrophils to the injection site of aggregated but not monometric gamma-globulin. Thus, leukocytic accumulation was found to be dependent upon the local generation of specific reactants that were particular to the agent employed. Leukocytic accumulation could also be modified by serum factors. Cellular accumulation was inhibited when leukocytes were exposed to serum that contained phagocytosable particles or after phagocytosis in vitro prior to adoptive transfer. Chemotaxis of lymphocytes could be induced by their preincubation with sera from adjuvant arthritic animals. These observations were confirmed by in vitro studies and by the finding that 6 days after adjuvant injection , lymphocytes but not mononuclear cells accumulated at the noninjected extremity. In the final series of experiments, it was shown that BCG immunization was capable of inducing a unique population of peritoneal mononuclear cells that after adoptive transfer had an enhanced capacity to remain in the circulation, which, in turn, resulted in a functional increase in their accumulation at an inflammatory reaction site. In conclusion, these studies indicated that the chemotactic activity of adoptively transferred cells can be modified by changes in the chemotactic stimuli, can be enhanced or depressed by serum factors, and is a function of the physiologic capability of the cell population employed.

Inhibition of HIV-1 replication by hydroxychloroquine: mechanism of action and comparison with zidovudine.

We have previously described the inhibition of human immunodeficiency virus serotype 1 (HIV-1) using the antimalarial hydroxychloroquine (HCQ), a weak base that inhibits the posttranslational modification of glycoprotein 120 (gp 120) in T cells and monocytes. The mechanism of inhibition of gp 120 production was presumed to be the ability of HCQ to increase endosomal pH and therefore alter enzymes required for gp120 production. To further clarify this action, we have determined the effect of HCQ and its enantiomers on endosomal pH. Pretreatment of cells with HCQ and the levo- and dextro-enantiomers at concentrations demonstrated to suppress anti-HIV-1 activity increased endosomal pH to levels similar to increases seen with chloroquine and ammonium chloride, two other weak bases, and decreased gp 120 production. The dextro- and levo-enantiomers suppressed HIV-1 replication to a similar extent and were no more toxic than racemic HCQ. We next compared the anti-HIV-1 effect of HCQ with zidovudine (ZDV) in both newly and chronically HIV-1-infected T-cell and monocytic cell lines (63 and 63HIV). HCQ suppressed HIV-1 replication in a dose-dependent manner in both recently and chronically infected T-cell and monocytic cell lines. In contrast, ZDV pretreatment had potent anti-HIV-1 activity in the newly infected T and monocytic cells but not in chronically infected cells. An additive effect of HCQ with ZDV was observed in the newly infected T and monocytic cells but not in the chronically infected cells. Although the anti-HIV-1 effect of HCQ was less than that of ZDV, HCQ may still be potentially useful either as an alternative HIV-1 treatment or in combination with other anti-HIV-1 agents, especially in patients who have rheumatic manifestations of HIV-1 infection.

Enhanced understanding of the relationship between erection and satisfaction in ED treatment: application of a longitudinal mediation model.

To apportion the direct effect and the indirect effect (through erections) that sildenafil (vs placebo) has on individual satisfaction and couple satisfaction over time, longitudinal mediation modeling was applied to outcomes on the Sexual Experience Questionnaire. The model included data from weeks 4 and 10 (double-blind phase) and week 16 (open-label phase) of a controlled study. Data from 167 patients with erectile dysfunction (ED) were available for analysis. Estimation of statistical significance was based on bootstrap simulations, which allowed inferences at and between time points. Percentages (and corresponding 95% confidence intervals) for direct and indirect effects of treatment were calculated using the model. For the individual satisfaction and couple satisfaction domains, direct treatment effects were negligible (not statistically significant) whereas indirect treatment effects via the erection domain represented >90% of the treatment effects (statistically significant). Week 4 vs week 10 percentages of direct and indirect effects were not statistically different, indicating that the mediation effects are longitudinally invariant. As there was no placebo arm in the open-label phase, mediation effects at week 16 were not estimable. In conclusion, erection has a crucial role as a mediator in restoring individual satisfaction and couple satisfaction in men with ED treated with sildenafil.

Clinically meaningful improvement on the quality of erection questionnaire in men with erectile dysfunction.

Defining the minimal clinically meaningful improvement (MCMI) is crucial to understanding the treatment effects on health-status measures. We estimated the MCMI on the quality of erection questionnaire (QEQ), a validated measure specific to assess erectile quality during sexual intercourse. Data were from two controlled trials of an investigational phosphodiesterase type 5 inhibitor. Improvement on the Erectile Function domain of the International Index of Erectile Function was used as the anchor. For men who improved by exactly 1 erectile dysfunction severity category (anchor group (n=95)), clinically meaningful improvement (CMI, estimated with mean QEQ total change score from baseline to end of treatment) and MCMI (estimated with the lower limit of the 95% confidence interval of the mean) were 22.4 (s.d., 2.2) and 18.0 points, respectively. For the difference between the anchor group and men with no change in severity category (n=116), CMI and MCMI were 17.7 (s.d., 2.9) and 12 points, respectively. Distribution-based analyses (baseline s.e. of measurement (s.e.m.)=7.99, end-of-treatment s.e.m.=8.22 and s.e. of difference=11.46) supported a proposed MCMI of 12 points. Convergence of anchor-based and distribution-based criteria supports at least a 12-point difference in QEQ scores between treatments as clinically important.

Hardness, function, emotional well-being, satisfaction and the overall sexual experience in men using 100-mg fixed-dose or flexible-dose sildenafil citrate.

The prescribing information for sildenafil citrate (VIAGRA, Pfizer, New York, NY, USA) recommends flexible dosing (50 mg initially, adjusted to 100 or 25 mg based on effectiveness and tolerability) in most men with erectile dysfunction (ED). In many men, however, 100 mg may be the most appropriate initial dose because it would reduce the need for titration and could prevent discouragement and treatment abandonment should 50 mg be insufficient. Results of two previously published double-blind, placebo-controlled sildenafil trials of similar design except for a fixed-dose vs flexible-dose regimen were analyzed. Relative to the flexible-dose, approximately one-third more men were satisfied with an initial and fixed dose of 100 mg. In addition, tolerability was similar, and improvements from baseline in outcomes on validated, ED-specific, patient-reported questionnaires were either similar (erectile function and the percentage of completely hard and fully rigid erections) or greater (emotional well-being and the overall sexual experience). The similarity in outcomes is not surprising given that almost 90% of the men in the flexible-dose trial titrated to 100 mg after 2 weeks. These data suggest prescription of an initial dose of 100 mg for men with ED, except in those for whom it is inappropriate.

An assessment of patient-reported outcomes for men with erectile dysfunction: Pfizer's perspective.

Patient-reported outcomes (PROs) for men with erectile dysfunction (ED) have blossomed in the published literature and at professional conferences. These outcomes have been central to study the science of ED itself and to evaluate efficacy of treatment for men with ED. In this review article we highlight and distinguish among seven key PROs: the International Index of Erectile Function, for sexual function including erectile function; the Sexual Health Inventory for Men (SHIM), for diagnosis of ED; the Quality of Erection Questionnaire, for satisfaction with quality of erections; the Erectile Dysfunction Inventory of Treatment Satisfaction, for personal evaluation of treatment received; the Self-Esteem And Relationship questionnaire, for emotional well-being; the Erection Hardness Score (EHS), for targeting erection hardness and the Sexual Experience Questionnaire, for erection (both function and quality), individual satisfaction and couples satisfaction. Depending on the purpose of the investigation, all seven PROs have merit for use in clinical trials and at least deserve consideration in clinical practice. The SHIM and the EHS, given their aims and brevity, deserve special consideration in clinical practice. As a unit these seven PROs complement and supplement each other. Which ones to choose in a particular undertaking depends on the objective or purpose of a given study. These PROs acknowledge that sexual dysfunction and its treatment have multiple dimensions. Each of these instruments represents a significant contribution to sexual medicine research and, when used judiciously and appropriately, can help to provide optimal patient care and management.

Self-esteem, confidence and relationship satisfaction in men with erectile dysfunction: a randomized, parallel-group, double-blind, placebo-controlled study of sildenafil in Mexico.

Erectile dysfunction (ED) negatively impacts self-esteem and relationship satisfaction. The Self-Esteem and Relationship (SEAR) questionnaire is a validated, ED-specific, patient-reported instrument that specifically addresses self-esteem and relationship issues within the context of ED. Effective ED treatment with sildenafil in a double-blind, placebo-controlled clinical trial conducted in Brazil, Mexico, Australia and Japan showed pooled cross-cultural improvements in self-esteem, confidence and relationship satisfaction. This report focuses on the results from the subgroup of men from nine Mexican centers who participated in the multinational study. A total of 95 men aged >or=18 years with clinically diagnosed ED and currently in a stable relationship were randomized to placebo (n=47) or sildenafil (n=48). The SEAR results for Mexican men showed that sildenafil treatment led to significant improvements in self-esteem, confidence and relationship satisfaction. These data support an earlier study showing that Latin American men taking sildenafil have similar safety and efficacy profiles compared to non-Latin counterparts.

A double blind, randomised study of sildenafil citrate for erectile dysfunction in men with multiple sclerosis.

OBJECTIVE: Identifying and effectively treating erectile dysfunction (ED) can result in an improvement of the quality of life (QoL) in men with multiple sclerosis (MS). METHODS: This randomised, double blind (DB), placebo controlled, flexible dose study with an open label extension (OLE) assessed efficacy, QoL, and safety of sildenafil citrate in men with MS and ED. Overall, 217 men received sildenafil (25-100 mg; n = 104) or placebo (n = 113) for 12 weeks. Efficacy was assessed by the International Index of Erectile Function (IIEF) questionnaire that includes questions on achieving (Q3) and maintaining (Q4) an erection as well as a global efficacy question (GEQ). QoL was also assessed. RESULTS: After 12 weeks, patients receiving sildenafil had higher mean scores for IIEF Q3 and Q4 compared with those receiving placebo (p<0.0001), and 89% (92/103) reported improved erections compared with 24% (27/112) of patients receiving placebo (p<0.0001). At the end of the OLE phase, 95% of men reported improved erections. Patients receiving placebo during the DB phase showed a nearly fourfold increase in improved erections (97% v 26%). Men receiving sildenafil also showed improvements in five of the eight general QoL questions compared with men receiving placebo (p<0.05). The total mean score for the QoL questionnaire improved by 43% for the sildenafil group versus 13% for the placebo group (p<0.0001). Treatment related AEs were predominantly mild in nature, and no patient discontinued due to an AE. CONCLUSION: Sildenafil treatment for ED in men with MS was effective and well tolerated, and resulted in significant improvements in both general and disease specific QoL variables.

The neutrophil adherence assay as a method for detecting unique anti-inflammatory agents.

Neutrophil adhesiveness is an important component of the pathophysiology of the inflammatory process. Modulation of this function could result in a reduction in the degree of inflammation and connective tissue damage. A simple technique using filtration of whole blood through nylon fiber columns has been developed to study the effect of anti-inflammatory agents on the adherence of rat peripheral blood neutrophils. Gold and chloroquine, in addition to many standard anti-inflammatory drugs, have been shown to cause inhibition of neutrophil adherence. Measurement of this parameter of cell behavior has the potential of detecting anti-inflammatory agents not normally effective in the standard animal models.

Effect of disease modifying antirheumatic drugs and nonsteroidal antiinflammatory drugs upon cellular and fibronectin responses in a pleurisy model.

Intrapleural injections of carrageenan into rats resulted in peak increases in intrapleural inflammatory cell counts (90% mononuclear cells) and fibronectin content at 3 days after the injections. Administration of disease modifying antirheumatic drugs (DMARD) prevented the increases in both fibronectin levels and intrapleural cell counts, whereas nonsteroidal antiinflammatory drugs, in general, potentiated the increases. Inhibition of fibronectin production by DMARD in carrageenan induced pleurisy in rats may be related to the antirheumatic activity of this class of drugs.

Examination of interleukin-1 activity, the acute phase response, and leukocyte subpopulations in rats with adjuvant-induced arthritis.

Rats with adjuvant-induced arthritis (AA) were used to determine whether chronic systemic paw inflammation was accompanied by appearance of the acute phase response, an increase in splenic interleukin-1 (IL-1) production, and a reduction of nonhelper T cells in the spleen and peripheral blood. Two weeks after injection of adjuvant, the rats developed significant (P less than or equal to 0.01) swelling of the noninjected paw indicative of systemic inflammation. The rats with AA also exhibited signs of the acute phase response, as measured by a significant increase in plasma C-reactive protein (138% above normal) and a significant decrease in plasma albumin (47% below normal), zinc (30% below normal), and iron (58% below normal). IL-1 production from spleen cells of rats with AA was increased 115% compared with normals. Results from immunofluorescence studies with W3/25 and OX8 antibodies to distinguish rat T-helper-inducer (TH) spleen cells from suppressor-cytotoxic (nonhelper T) spleen cells indicated no significant difference between the percentage of OX8+ cells in spleens of arthritic rats compared with OX8+ cells in spleens of normal rats. The W3/25+-to-OX8+ ratio of 1.6 +/- 0.2 for normal rat spleen cells (33% to 21%) was not significantly different from the arthritic rat ratio of 1.9 +/- 0.1 (36% to 19%). When the phenotypes of peripheral blood mononuclear cells were analyzed, the normal animals possessed a greater percentage of W3/25+(TH) cells than did rats with AA. Normal blood mononuclear cell samples were composed of 51% +/- 3% W3/25+ cells and 22% +/- 2% OX8+ cells, and the samples from rats with AA contained 43% +/- 4% W3/25+ cells and 24% +/- 3% OX8+ cells. Thus, the helper-to-nonhelper ratio was higher for normal rats (2.3 +/- 0.1) than for arthritic rats (1.8 +/- 0.2). The data indicated that the appearance of the acute phase response and the abnormally high rate of splenic IL-1 production in the rats with AA did not stem from a subnormal percentage of OX8+ nonhelper T cells in the spleen or peripheral blood.

Single-step purification of rat C-reactive protein and generation of monospecific C-reactive protein antibody.

Although Sepharose-phosphorylcholine affinity chromatography has been used extensively to purify some acute phase proteins, the operation has usually been a laborious multi-step procedure. By modifying previously described multi-step protein purification assays, centigram quantities of pure rat C-reactive protein (CRP) could be obtained in a single chromatographic step using affinity chromatography. Rat serum was passed over a column of p-aminophenylphosphorylcholine and extraneous proteins eluted with Tris-saline-Ca2+ buffer. Similar to other purification procedures, CRP was eluted with phosphorylcholine in a Tris-saline-Ca2+ buffer. The technical detail which distinguished this procedure from others, was the use of a phosphorylcholine gradient shallow enough (0.95 mM-2.5 mM) to resolve the eluent into two peaks; the first peak was composed largely of the contaminant, serum amyloid protein (SAP), and the second was composed of CRP. Although there was some overlap between the first and second peak, pure CRP could be obtained by pooling fractions from the trailing shoulder of the second peak. Using this single step procedure, a greater than 25% yield of SAP-free, purified CRP could be obtained. The purified CRP was free of SAP contamination as measured by sodium dodecyl sulfate gradient polyacrylamide gel electrophoresis. Purified CRP was determined to be free of rat albumin, IgG and the C3 component of complement using immunoelectrophoresis. This one-step affinity column chromatography procedure provides a simple, efficient method for collecting large quantities of rat CRP pure enough to be used to obtain a monospecific goat, anti-rat CRP antibody.