ATOMDANCE: Kernel-based denoising and choreographic analysis for protein dynamic comparison

Comparative methods in molecular evolution and structural biology rely heavily upon the site-wise analysis of DNA sequence and protein structure, both static forms of information. However, it is widely accepted that protein function results from nanoscale nonrandom machine-like motions induced by evolutionarily conserved molecular interactions. Comparisons of molecular dynamics (MD) simulations conducted between homologous sites representative of different functional or mutational states can potentially identify local effects on binding interaction and protein evolution. In addition, comparisons of different (i.e., nonhomologous) sites within MD simulations could be employed to identify functional shifts in local time-coordinated dynamics indicative of logic gating within proteins. However, comparative MD analysis is challenged by the large fraction of protein motion caused by random thermal noise in the surrounding solvent. Therefore, properly denoised MD comparisons could reveal functional sites involving these machine-like dynamics with good accuracy. Here, we introduce ATOMDANCE, a user-interfaced suite of comparative machine learning-based denoising tools designed for identifying functional sites and the patterns of coordinated motion they can create within MD simulations. ATOMDANCE-maxDemon4.0 employs Gaussian kernel functions to compute site-wise maximum mean discrepancy between learned features of motion, thereby assessing denoised differences in the nonrandom motions between functional or evolutionary states (e.g., ligand bound versus unbound, wild-type versus mutant). ATOMDANCE-maxDemon4.0 also employs maximum mean discrepancy to analyze potential random amino acid replacements allowing for a site-wise test of neutral versus nonneutral evolution on the divergence of dynamic function in protein homologs. Finally, ATOMDANCE-Choreograph2.0 employs mixed-model analysis of variance and graph network to detect regions where time-synchronized shifts in dynamics occur. Here, we demonstrate ATOMDANCE's utility for identifying key sites involved in dynamic responses during functional binding interactions involving DNA, small-molecule drugs, and virus-host recognition, as well as understanding shifts in global and local site coordination occurring during allosteric activation of a pathogenic protease.

Rolling the evolutionary dice: Neisseria commensals as proxies for elucidating the underpinnings of antibiotic resistance mechanisms and evolution in human pathogens

Species within the genus Neisseria are adept at sharing adaptive allelic variation, with commensal species repeatedly transferring resistance to their pathogenic relative Neisseria gonorrhoeae. However, resistance in commensals is infrequently characterized, limiting our ability to predict novel and potentially transferable resistance mechanisms that ultimately may become important clinically. Unique evolutionary starting places of each Neisseria species will have distinct genomic backgrounds, which may ultimately control the fate of evolving populations in response to selection as epistatic and additive interactions coerce lineages along divergent evolutionary trajectories. Alternatively, similar genetic content present across species due to shared ancestry may constrain existing adaptive solutions. Thus, identifying the paths to resistance across commensals may aid in characterizing the Neisseria resistome-or the reservoir of alleles within the genus as well as its depth. Here, we use in vitro evolution of four commensal species to investigate the potential and repeatability of resistance evolution to two antimicrobials, the macrolide azithromycin and the β-lactam penicillin. After 20 days of selection, commensals evolved resistance to penicillin and azithromycin in 11/16 and 12/16 cases, respectively. Almost all cases of resistance emergence converged on mutations within ribosomal components or the mtrRCDE efflux pump for azithromycin-based selection and mtrRCDE, penA, and rpoB for penicillin selection, thus supporting constrained adaptive solutions despite divergent evolutionary starting points across the genus for these particular drugs. Though drug-selected loci were limited, we do identify novel resistance-imparting mutations. Continuing to explore paths to resistance across different experimental conditions and genomic backgrounds, which could shunt evolution down alternative evolutionary trajectories, will ultimately flesh out the full Neisseria resistome.IMPORTANCENeisseria gonorrhoeae is a global threat to public health due to its rapid acquisition of antibiotic resistance to all first-line treatments. Recent work has documented that alleles acquired from close commensal relatives have played a large role in the emergence of resistance to macrolides and beta-lactams within gonococcal populations. However, commensals have been relatively underexplored for the resistance genotypes they may harbor. This leaves a gap in our understanding of resistance that could be rapidly acquired by the gonococcus through a known highway of horizontal gene exchange. Here, we characterize resistance mechanisms that can emerge in commensal Neisseria populations via in vitro selection to multiple antimicrobials and begin to define the number of paths to resistance. This study, and other similar works, may ultimately aid both surveillance efforts and clinical diagnostic development by nominating novel and conserved resistance mechanisms that may be at risk of rapid dissemination to pathogen populations.

Rolling the evolutionary dice: Neisseria commensals as proxies for elucidating the underpinnings of antibiotic resistance mechanisms and evolution in human pathogens

Species within the genus Neisseria are especially adept at sharing adaptive allelic variation across species' boundaries, with commensal species repeatedly transferring resistance to their pathogenic relative N. gonorrhoeae. However, resistance in commensal Neisseria is infrequently characterized at both the phenotypic and genotypic levels, limiting our ability to predict novel and potentially transferable resistance mechanisms that ultimately may become important clinically. Unique evolutionary starting places of each Neisseria species will have distinct genomic backgrounds, which may ultimately control the fate of evolving populations in response to selection, as epistatic and additive interactions may coerce lineages along divergent evolutionary trajectories. However alternatively, similar genetic content present across species due to shared ancestry may constrain the adaptive solutions that exist. Thus, identifying the paths to resistance across commensals may aid in characterizing the Neisseria resistome - or the reservoir of alleles within the genus, as well as its depth. Here, we use in vitro evolution of four commensal species to investigate the potential for and repeatability of resistance evolution to two antimicrobials, the macrolide azithromycin and the β-lactam penicillin. After 20 days of selection, commensals evolved elevated minimum inhibitory concentrations (MICs) to penicillin and azithromycin in 11/16 and 12/16 cases respectively. Almost all cases of resistance emergence converged on mutations within ribosomal components or the mtrRCDE efflux pump for azithromycin-based selection, and mtrRCDE or penA for penicillin selection; thus, supporting constrained adaptive solutions despite divergent evolutionary starting points across the genus for these particular drugs. However, continuing to explore the paths to resistance across different experimental conditions and genomic backgrounds, which could shunt evolution down alternative evolutionary trajectories, will ultimately flesh out the full Neisseria resistome.

Modality of choice for renal replacement therapy for children with acute kidney injury: Results of a survey

Information on current practices in India for management of renal replacement therapy (RRT) in acute kidney injury (AKI) is lacking. We mailed a questionnaire to 26 pediatric nephrology centers across India to obtain information on the current choice of dialysis modality for management of AKI in children. Acute intermittent peritoneal dialysis was available at all centers surveyed, whereas intermittent hemodialysis and continuous RRT were available in 86% and 17% centers, respectively. Peritoneal dialysis was the predominant modality (accounting for more than 80% of all dialysis) in 14 of the 22 centers, while 4 centers used hemodialysis more commonly. The most important factors influencing the modality choice were patient size, hemodynamic stability, and duration of AKI. These results provide insight into the choice of modality and factors influencing their selection in the management of pediatric AKI in our country.

Growth in Pediatric Renal Transplant Recipients

One of the fundamental challenges in managing pediatric renal transplant recipient is to ensure normal growth and development. The goal of renal transplant is not just to prolong life but to optimize quality of life. Short stature during childhood may be associated with academic underachievement and development of comorbidities such as attention deficit hyperactivity disorder, learning disability, and mood disorders. The most important factors affecting growth are use of corticosteroids, allograft function, and age and height deficit at the time of transplant. Aggressive conservative management of chronic renal failure and early use of growth hormone therapy will help in optimizing height at time of transplant. Early transplant, steroid minimization or withdrawal, and growth hormone therapy will help in achieving normal adult height in a majority of renal post transplant population. Steroid avoidance to achieve good growth still needs to be validated.

Defensive hostility and coronary heart disease: a preliminary investigation of male veterans

OBJECTIVE

Research and theory link an interpersonal conflict model to cardiovascular disease. Specifically, persons scoring high on cynical hostility and social defensiveness are thought to manifest a defensive need for approval while harboring basic distrust and hostility toward those who could provide such approval. The objective of this study was to assess whether angiographically determined coronary artery disease (CAD) was associated with this combination of high cynical hostility and high social defensiveness.

METHODS

Fifty-nine male patients of a Veterans Administration Medical Center (86% white, mean age = 59.9 years) participated in the study on the day before their angiographic procedure; these men filled out the Cook-Medley Hostility Scale and the Marlowe-Crowne Social Desirability Scale (social defensiveness). They subsequently were categorized as having defensive hostility (DH), high hostility (HH), high social defensiveness (SD), or low psychosocial risk (LRisk; low on both scales).

RESULTS

The four groups did not differ significantly on risk factor status or health status. As predicted, a preplanned contrast showed that the DH group's mean number of arteries with at least 50% blockage (mean = 2.5) differed significantly from the combined means of the other groups. The HH and SD groups did not differ from the LRisk group.

CONCLUSIONS

When combined with other reports, the approach-avoidance interpersonal conflict model holds the promise of providing additional information about the psychosocial factors contributing to CAD development among men with high cynical hostility.

Use of nitric oxide inhalation in chronic obstructive pulmonary disease

BACKGROUND

Inhalation of nitric oxide with oxygen could be a promising treatment in patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension. However, the current methods of delivery of NO are cumbersome and unsuitable for long term use. The present study was undertaken to investigate the safety and efficacy of a mixture of nitric oxide (NO) and oxygen administered via a nasal cannula for 24 hours in patients with oxygen dependent COPD.

METHODS

Twenty five parts per million (ppm) of NO was administered by inhalation combined with supplemental oxygen at a flow rate of 2 l/min via a nasal cannula for 24 hours to 11 ambulatory men with stable, oxygen dependent COPD. Room air with supplemental oxygen at 2 l/min was administered in an identical manner for another 24 hours as control therapy in a randomised, double blind, crossover fashion to all patients. Pulmonary function tests, exercise tolerance, dyspnoea grade, and lung volumes were measured at baseline, 24, and 48 hours. Pulmonary artery pressure (PAP), cardiac output (CO), pulmonary vascular resistance (PVR), arterial blood gas tensions, and minute ventilation were measured at baseline, after 30 minutes and 24 hours of breathing NO and oxygen. Venous admixture ratio (Qs/Qt) and dead space ratio (Vd/Vt) were also calculated. Concentrations of nitrogen dioxide (NO(2)) and NO in the inhaled and ambient air were monitored continuously. Differences in pulmonary function, arterial blood gas tensions, pulmonary haemodynamics, exercise tolerance, and dyspnoea between oxygen and NO breathing periods were analysed for significance using paired t tests.

RESULTS

A significant (p<0.05) fall was observed in PVR (183.1 (116.05) and 137.2 (108.4) dynes.s.cm(-3) before and after breathing NO for 24 hours, respectively) with NO administration without significant changes in symptoms, pulmonary function, arterial oxygen tension, or exercise tolerance.

CONCLUSIONS

NO at a concentration of 25 ppm blended with oxygen can be safely administered by nasal cannula for 24 hours without significant adverse effects and lowers PVR in stable patients with COPD receiving long term oxygen therapy.

Pediatric renal transplantation--Indian experience

OBJECTIVE

To analyze our experience with renal transplantation in children with end-stage renal disease (ESRD) in India.

DESIGN

Retrospective study.

METHODS

Over the last 7.5 years, 27 renal transplants were performed on children below 12 years of age, 8 children were less than 6 years old, 19 were between 6 and 12 years of age. Sixteen children had underlying glomerular disease while eleven had tubulointerstitial renal disease. Transperitoneal approach was used in smaller recipients weighing less than 12 kg. Extraperitoneal approach was used in the remainder. Triple immunosuppression with Cyclosporine, Azathioprine and Steroids was used in all cases.

RESULTS

Follow-up period ranged from 6 months to 7.5 years (mean 3.7 years). There were 10 episodes of acute rejection. Three cases of acute rejection failed to respond to therapy. No surgical complications were encountered. Graft survival was 73.2% at one year and 71% at two years. Satisfactory rehabilitation was achieved in children with functioning grafts.

CONCLUSIONS

Renal transplantation in children in India offers an acceptable choice in ESRD as anywhere in the world.

Cyclosporine experience in nephrotic syndrome

OBJECTIVE

To analyze the use of Cyclosporine (CyA) in nephrotic syndrome.

METHODS

Thirty five children of mean age of 5.9 years with steroid dependent (n = 26) or steroid resistant (n = 9) primary nephrotic syndrome with normal renal functions and who received CyA were studied. CyA was used at a dosage of 6-7 mg/kg/day orally in two divided doses. The mean duration of therapy was 9.6 weeks. All received a minimum of 8 weeks of CyA therapy. In a few who received longer therapy, the dose was reduced to 4 mg/kg/day. All patients were monitored serially for hepatotoxicity and nephrotoxicity. The nephrotic state was evaluated serially with biochemical tests and followed up for a mean period of 2.55 years.

RESULTS

Thirty one patients completed the study. The response to therapy was categorized into 5 groups-no response (4 patients), good response (4 patients), partial response (4 patients), cyclosporine dependence (16 patients), and infrequent relapsers (3 patients). Good response was defined as complete remission lasting for at least one year after cessation of therapy. Patients who showed partial response had reduction in quantitative proteinuria and needed less diuretics. Sixteen patients went into complete remission while on therapy but relapsed within 3 months of discontinuation (CyA dependence). The response to CyA correlated more with steroid-responsiveness than with the underlying histopathology. The drug was well tolerated.

CONCLUSION

In steroid-dependent or steroid-resistant nephrotic children with normal renal functions, CyA therapy may be considered as one of the possible therapeutic options. Our results suggest that a longer duration of CyA therapy may possibly be indicated in these cases.

A randomized trial of cimetidine with 5-fluorouracil and folinic acid in metastatic colorectal cancer

Cimetidine has demonstrated a survival benefit in a randomized trial as adjuvant therapy for gastric cancer. We have demonstrated expression of histamine receptors on colon cancer cell lines and inhibition of their growth with cimetidine. Cimetidine also activates suppressor T cells and stimulates cell-mediated immunity. We therefore performed a randomized controlled clinical trial to determine the effect of cimetidine 400 mg given twice daily in conjunction with chemotherapy vs chemotherapy alone. Thirty-eight patients were randomized and 35 patients were eligible for further analysis. Both groups were well matched for pre-treatment characteristics. There was no difference in overall response. There was, however, a significantly increased rate of CEA response in the cimetidine group. Four of 11 patients (36%) in the cimetidine group had a CEA response compared to none of eight in the control. Meaningful comparisons of overall survival cannot yet be made. This study demonstrates that cimetidine has encouraging activity in increasing CEA response in patients with metastatic colorectal cancer treated with chemotherapy. This observation needs to be extended in a larger randomized study, which is currently underway.

Conditioned medium from a cell strain derived from a patient with mastocytosis induces the development of mature human mast cells in vitro from normal human bone marrow

Mature human mast cells were obtained from human bone marrow in a coculture system using conditioned medium from a human mastocytosis cell strain. These cells expressed the high-affinity IgE receptor and were tryptase, chymase and carboxypeptidase positive.

Conditioned media from a cell strain derived from a patient with mastocytosis induces preferential development of cells that possess high affinity IgE receptors and the granule protease phenotype of mature cutaneous mast cells

We have demonstrated for the first time that a conditioned medium from a human cell strain can induce morphologically mature mast cells that express Fc epsilon RI and three mast cell-specific proteases from normal bone marrow progenitor cells. In contrast, recombinant human Kit ligand induced the differentiation of mast cells that were tryptase-positive but negative for chymase, carboxypeptidase, and Fc epsilon RI. This data indicates that factors other than Kit ligand are critical for inducing the differentiation and maturation of mast cells in the human. The HBM-M cell was originally derived from a patient with mastocytosis. As mastocytosis is thought to represent a reactive hyperplasia rather than a mast cell malignancy, the factor secreted by the HBM-M cell strain could well be responsible for the mast cell hyperplasia seen in some patients with mastocytosis.

Rheumatic autoantibodies in the sera of patients with paraproteins

OBJECTIVE

A high incidence of autoantibody activity has been previously described in the sera of patients with paraproteins. In this study we determined the incidence of autoantibodies of particular interest to rheumatologists (including antinuclear antibodies (ANA), anti-DNA, rheumatoid factor (RF), anticardiolipin antibodies (aCL) and the Sjögren's-related antibodies anti-SS.A/Ro and anti-SS.B/La) in the sera of patients with paraproteins, and the frequency with which the autoantibody activity isotype and the paraprotein isotype were identical.

METHODS

ANA was determined by indirect immunofluorescence on HEp2 cells, anti-DNA by the Farr and Crithidia assays, aCL by ELISA, RF by nephelometry, antibodies to the extractable nuclear antigens (anti-ENA) by counter-immunoelectrophoresis (CIE), and anti-SS.B by immunoblot using a recombinant human SS.B antigen source. Incidences of these antibodies was compared in 3 groups of sera: 98 myeloma, 27 monoclonal gammopathy of uncertain significance (MGUS), and 24 age matched controls, using confidence interval analysis.

RESULTS

There was no significant difference between the incidence of ANAs in paraprotein sera (8.8%) and control sera (16%). Neither was there a significant incidence of RF or aCL in the paraprotein sera. No anti-DNA antibodies were found and no anti-SS.B antibodies were found either with CIE or immunoblotting. Of the 11 ANAs detected in the paraprotein sera, isotype specific immunofluorescence suggested that 6 were monoclonal autoantibodies.

CONCLUSIONS

These results indicate that the incidence of rheumatic autoantibodies is not raised in paraprotein sera compared to control sera. In particular, we could not confirm previous reports of a high incidence of anti-SS.B antibodies. However, of the ANAs detected half were monoclonal, unlike the polyclonality of the ANAs in the control group. That 4.8% of the paraproteins were monoclonal ANAs suggests that the process leading to paraproteinemia may activate usually silent autoreactive B cells as well as the normal B cell repertoire.

Atenolol or nicardipine alone is as efficacious in stable angina as their combination: a double blind randomised trial

BACKGROUND

Beta blockers and calcium antagonists are widely used in the management of angina pectoris in the belief that the combination is more efficacious than either drug alone.

METHODS

This double blind randomised crossover placebo controlled study compares the effects of nicardipine, atenolol and their combination in 30 patients with chronic stable angina. Each treatment period lasted 6 weeks with dose titration after 3 weeks. Symptom limited treadmill exercise testing and radionuclide ventriculography at rest was carried out at the end of each treatment period.

RESULTS

Total exercise duration and time to 1-mm ST-segment depression was significantly prolonged by nicardipine and atenolol when compared to placebo, the combination offered no additional benefit. Time to onset of angina was significantly prolonged by nicardipine and the combination but not by atenolol. Indices of left ventricular function were not significantly affected by any treatment other than an increase in left ventricular end diastolic volume on atenolol and the combination.

CONCLUSIONS

Nicardipine and atenolol are equally effective in prolonging exercise duration and time to onset of ischemia in patients with chronic stable angina while the combination appeared to offer no additional benefit. Nicardipine prolonged the time to onset of angina significantly; again there was no further improvement with the combination. Neither drug appears to have an important effect on the parameters of diastolic function studied in patients with chronic stable angina.

Balloon angioplasty of adult aortic coarctation

OBJECTIVE

To examine the use of balloon angioplasty in the treatment of native adult aortic coarctation.

DESIGN

Haemodynamic and angiographic studies to establish the diagnosis of aortic coarctation were established before carrying out the procedure in all patients.

SETTING

All the studies and angiographic procedures were performed in a large district general hospital within the departments of cardiology and radiology. There was careful perioperative monitoring. The mean hospital stay was three days.

PATIENTS

15 adult patients (with clinical, haemodynamic, and angiographic evidence of native aortic coarctation) were considered for this treatment. 13 were offered balloon angioplasty. One was excluded, as there was no significant gradient across the lesion. One patient had complete atresia at the site of the coarctation.

INTERVENTIONS

Percutaneous transluminal balloon angioplasty was carried out with balloon catheters diameter 2 mm less than the diameter of the aorta immediately below the left subclavian artery to minimise the possibility of tearing the aortic wall.

MAIN OUTCOME MEASURES

Abolition or significant reduction of the preoperative gradient was achieved in all 13 patients treated. Reduction in blood pressure of the upper limb was also achieved in all of the patients. Only four patients required continued antihypertensive treatment. Two patients developed false aneurysms after the procedure and required surgery. No deaths occurred. These results compare favourably with conventional surgery and are much more economical.

CONCLUSIONS

Balloon angioplasty could become the first line treatment for all patients with native adult aortic coarctation, but longer term follow up is required to validate this.

Effects of coronary artery bypass surgery and angioplasty on the total ischemic burden: a study of exercise testing and ambulatory ST segment monitoring

To assess the effects of standard therapeutic interventions on the total ischemic burden, 86 patients with stable angina underwent 48 hours of ambulatory ST segment monitoring and treadmill exercise testing before and at a mean of 10 weeks after coronary artery bypass surgery (CABG) (group 1, N = 46) or percutaneous transluminal coronary angioplasty (PTCA) (group 2, N = 40). There were 72 male and 14 female patients with a mean age of 56.4 years. All patients had documented coronary artery disease (24, single-vessel; 28, two-vessel; 34, three-vessel disease). Both groups were characteristically similar apart from more severe coronary artery disease (p less than 0.001) and more previous myocardial infarctions (p less than 0.05) in group 1. Groups with CABG and PTCA had significant prolongation of exercise time after intervention (group 1: 7.6 to 9.8 minutes, p less than 0.0001; group 2: 8.1 to 10.0 minutes, p less than 0.001), and both interventions led to a significant reduction in ischemic responses (group 1: 33 to 4, p less than 0.001; group 2: 20 to 13, p less than 0.05) to exercise. During a total of 7643 hours of ST segment monitoring, 253 episodes of ischemia were recorded in 3768 hours before and 44 ischemic episodes in 3875 hours after intervention (group 1, 113 episodes in 24 patients and 21 episodes in 10 patients; group 2, 140 episodes in 13 patients and 23 episodes in six patients). Both interventions reduced the mean frequency of ischemia per 24 hours (group 1: 1.24 to 0.22 episodes per 24 hours; p less than 0.01; group 2: 1.9 to 0.3 episodes per 24 hours; p less than 0.05). Almost 28% (N = 24) of resting electrocardiographic findings were altered as a result of intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical validation of four solid state ambulatory monitoring devices in detecting shift of the ST segment

Continuous monitoring for detection of changes in the ST segment during daily life in patients with stable angina has received increasing attention in recent years. Various reports testify to its role in the detection of silent ischaemia, and its potential usefulness in stratification of risk. Frequency modulated recorders, using magnetic tape for recording with subsequent visual analysis, have been previously validated for the detection of such changes. Analysis, however, is time consuming, and is subject to technical faults due to the presence of moving parts. Several new solid state devices have become available in recent years which provide real-time automated analysis, and have theoretically ideal recording capabilities with frequency response down to 0.05 Hz and linear phase integrity which may be as good, or better than, tape based recorders. We compared each of four solid state devices with a previously validated frequency modulated recording device in patients with angina in order to assess whether such devices correlate well in detecting changes in the ST segment.

Interleukin-1-induced alterations in proteoglycan metabolism and matrix assembly

In cartilage, the large chondroitin sulfate proteoglycan exists as aggregates by interacting with link protein and hyaluronic acid. In diseases associated with cartilage degeneration, the proteoglycan does not aggregate because of a defect in the hyaluronate-binding activity. Since interleukin-1 (IL-1) is a secretory product of activated macrophages and may influence the cartilage function in joints, we studied the effects of IL-1 on the synthesis and assembly of proteoglycan by rabbit articular chondrocytes in culture. IL-1-treated cells showed a modest increase in the total proteoglycan synthesis, but also showed a more pronounced decrease in the incorporation of extracellular matrix. Affinity chromatography of the conditioned media on hyaluronic acid-Sepharose revealed that all of the proteoglycan of control cells strongly bound to hyaluronate. The IL-1-treated medium contained two fractions: one that was strongly bound to the column and a second that did not bind. The results demonstrate that the IL-1-treated cells cannot incorporate proteoglycan into the matrix partly because of a defect in the proteoglycan molecules and partly due to other mechanisms regulating proteoglycan assembly.

Regulation of cellular and humoral immune responses to collagen type I or collagen type II

We have investigated the characteristics of antigen-specific reductions in murine immune responses to rat collagen type I (R-CI), chick collagen type II (C-CII) or bovine collagen type II (B-CII). Intravenous pretreatment with the appropriate soluble collagen or collagen-coupled spleen cells led to the development of antigen-specific reduced immune responses, the former treatment being more effective than the latter. In the case of CII, pretreatment with R-CI or non-related antigens was ineffective. However, pretreatment with denatured bovine-CII, native bovine-CII or chick-CII led to immune hyporesponsiveness for either the homologous or heterologous CII molecule. A delayed development of the diminished immune responses was observed for the cell-mediated immune response (CMI), as measured by in vivo delayed-type hypersensitivity (DTH), in that no reduction was evident at Day 7 but a significantly decreased response was observed at Day 14. Collagen-specific IgG and IgM antibody responses were consistently reduced by the pretreatment and remained reduced during the study period. The antigen-specific hyporesponsive state was not sensitive to cyclophosphamide treatment and was not transferable with hyporesponsive spleen cells. Additionally, we have induced unresponsiveness to CII by treating mice with an antibody directed to T helper cells (GK1.5). This treatment led to profound reductions in CII CMI responses as well as CII antibody levels. However, this unresponsive state is not permanent and not transferable with spleen cells from treated mice. These two types of procedures, soluble B-CII i.v. or GK1.5 treatment, not only resulted in CII hyporesponsive states, but also produced delayed onset and decreased incidence of arthritis in the appropriate strains.

Myocardial infarction due to amphetamine

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Fibroblast growth factor enhances the interleukin-1-mediated chondrocytic protease release

The unfractionated macrophage-conditioned medium stimulates the chondrocytes to produce high levels of proteases. Purified IL-1 preparations exhibit significantly lower activity towards chondrocytes. This IL-1 mediated effect can be enhanced in presence of fibroblast growth factor, suggesting that other factors may collaborate with IL-1, in events leading to the cartilage destruction in vivo.

Paucity of minimal-change lesion in children with early frequently relapsing steroid-responsive nephrotic syndrome

It is widely believed that the most common morphological lesion in children with the idiopathic nephrotic syndrome who manifest a frequently relapsing steroid-responsive course is the minimal-change lesion. However, there are no prospective renal biopsy studies in such patients to substantiate this assertion. We performed a renal biopsy in all children with early frequently relapsing steroid-responsive nephrotic syndrome during the years 1980-1984. In 16 affected children, only 4 (25%) had minimal-change lesion, 7 had IgM nephropathy, 3 had diffuse mesangial hypercellularity, and 2 had focal segmental glomerulosclerosis. Fourteen of these patients have required immunosuppressive therapy with cyclophosphamide. Long-term follow-up revealed that 10 patients have remained protein free, 4 have persistent proteinuria despite cyclophosphamide therapy, 1 had progressed to end-stage renal disease, and 1 is lost to follow-up. On the basis of these findings, we recommend that all children with nephrotic syndrome and an early frequently relapsing steroid-responsive course undergo a prompt renal biopsy. Such patients constitute a high-risk group with a spectrum of renal histopathological lesions characterized by an unpredictable response to therapy and an unfavorable prognosis.

A second Australian family with hemoglobin North Shore (beta 134 Val----Glu)

A second Australian family is reported with Hemoglobin North Shore (beta 134 Val----Glu), an unstable hemoglobin, causing no clinical symptoms. All affected family members showed only mild reticulocytosis and microcytosis on the blood film, despite the strongly positive isopropanol test for Hb (hemoglobin) stability and numerous red cell inclusions. Hb North Shore constituted 31-38% of the total hemoglobin and migrated on the anodal side of Hb A at pH 8.9. The association of a mildly raised Hb A2 level and thalassemic phenotype with Hb North Shore previously reported, is confirmed in this study.

Characteristics of cellular immune responses to collagen type I or collagen type II

We have examined the murine cell-mediated immune (CMI) response to collagens type I (CI) and type II (CII) as measured by in vivo delayed-type hypersensitivity responses. We have verified the histopathology and kinetics of the cell-mediated immune responses. Predominant cell-mediated responses were obtained 7, 10, or 14 days following immunization. A presumed antibody-mediated reaction was observed at later times (e.g., greater than 21 days following immunization). The CMI responses to the collagens show a strain-dependent relationship. For CI, the CMI response profile shows H-2b greater than or equal to H-2k = H-2q much greater than H-2d. For bovine CII, the response profile is H-2d greater than H-2b = H-2k = H-2q; the chick CII response profile is H-2q = H-2k greater than H-2b = H-2d, and in limited testing, only the H-2q strain could generate murine CII-specific cell-mediated immune responses. The CII-specific CMI response is cross-reactive with CII from several species of animals, but not with CI. Further, the collagen-specific CMI response can be elicited with certain cyanogen-bromide fragments of bovine CII. Finally, our study also demonstrates that there is a non-H-2-linked locus(i) involved in the development of CII-induced arthritis.

Role of interleukin 1 and interleukin 2 in rat and mouse arthritis models

The production of interleukin 1 (IL 1) and interleukin 2 (IL 2) by macrophages and lymphocytes from three animal models commonly used for rheumatoid arthritis, viz. adjuvant-induced and type II collagen-induced rat arthritis, and MRL/1 murine arthritis was studied. Although the peritoneal macrophages from adjuvant-arthritic rats in culture produced increased amounts of prostaglandin E2 (PGE2) and lower levels of IL 1 than the control group, cells from collagen-arthritic rats released normal levels of PGE2, but increased amounts of IL 1. After activation with lipopolysaccharides, the IL 1 production by macrophages from all groups was comparable. Addition of indomethacin did not significantly change the IL 1 production in any of these groups. In the absence of any exogenous mitogen, IL 2 production by the lymphocytes of adjuvant-arthritic rats was low, but could be restored to the normal levels when phytohemagglutinin A (PHA) or concanavalin A (Con A) was added. The lymphocytes from collagen-arthritic rats were capable of producing IL 2 without the need of any T cell mitogen. The lymphocytes from MRL/1 mice seemed to lack the functionality in terms of IL 2 production. The macrophagic IL 1 production in these animals was normal. Our data suggest that the type II collagen arthritis model may closely resemble human rheumatoid arthritis in which IL 1 and IL 2 production by the mononuclear cells is significantly enhanced.

Role of interleukin 1 and interleukin 2 in rat and mouse arthritis models

The production of interleukin 1 (IL 1) and interleukin 2 (IL 2) by macrophages and lymphocytes from three animal models commonly used for rheumatoid arthritis, viz. adjuvant-induced and type II collagen-induced rat arthritis, and MRL/1 murine arthritis was studied. Although the peritoneal macrophages from adjuvant-arthritic rats in culture produced increased amounts of prostaglandin E2 (PGE2) and lower levels of IL 1 than the control group, cells from collagen-arthritic rats released normal levels of PGE2, but increased amounts of IL 1. After activation with lipopolysaccharides, the IL 1 production by macrophages from all groups was comparable. Addition of indomethacin did not significantly change the IL 1 production in any of these groups. In the absence of any exogenous mitogen, IL 2 production by the lymphocytes of adjuvant-arthritic rats was low, but could be restored to the normal levels when phytohemagglutinin A (PHA) or concanavalin A (Con A) was added. The lymphocytes from collagen-arthritic rats were capable of producing IL 2 without the need of any T cell mitogen. The lymphocytes from MRL/1 mice seemed to lack the functionality in terms of IL 2 production. The macrophagic IL 1 production in these animals was normal. Our data suggest that the type II collagen arthritis model may closely resemble human rheumatoid arthritis in which IL 1 and IL 2 production by the mononuclear cells is significantly enhanced.

Evaluation of the effects of various anti-arthritic drugs on type II collagen-induced mouse arthritis model

A battery of drugs which are commonly used as therapeutic agents for arthritis was tested for effects on the inflammatory and immunological responses of DBA/1J mice, after immunization with type II collagen. All the drugs were tested at more than one dosage. The mice were protected from the development of arthritis by treatment with paramethasone (0.25 mg/kg/day) or cyclophosphamide (5 mg/kg/day). The nonsteroidal anti-inflammatory drugs used in these studies, viz. aspirin (200 mg/kg/day), benoxaprofen (100 mg/kg/day) and naproxen (200 mg/kg/day), had no significant effect on the joint involvement, although naproxen and benoxaprofen at these high doses caused some reduction of immune responses of mice to collagen. Chloroquine (100 mg/kg/day), levamisol (50 mg/kg/day) and gold chlorophosphene (5 mg/kg/day) had no effect on the inflammatory or humoral response, while treatment with D-penicillamine (100 mg/kg/day) led to an early onset of arthritis in mice. These data suggest that the type II collagen-induced mouse arthritis model may not be highly suitable for detection of the traditional nonsteroidal anti-inflammatory class of drugs or the anti-rheumatic drugs, although the possibility remains that some new and novel immunosuppressive agents may be detected with this model.

Renal lesions in sickle cell nephropathy in children

Sickle cell nephropathy characterized by proteinuria and predominantly glomerular lesions has not been studied as extensively as renal tubular alterations in sickle cell disease. We reviewed our experience with this entity over a 14-year period. Of 13 children with either proteinuria or the nephrotic syndrome, 8 showed focal and segmental glomerulosclerosis, and 5 had mesangial proliferation. Children with focal and segmental glomerulosclerosis were older at onset of nephropathy and presented with the nephrotic syndrome more frequently than those with mesangial proliferation (p less than 0.05). All patients with mesangial proliferation and half of the focal and segmental glomerulosclerosis patients had supranormal renal clearances at onset of nephropathy suggesting hyperfiltration. Hyperfiltration seen in animals with reduced renal mass, and in human diabetic nephropathy before reduction in nephron units leads to mesangial proliferation and sclerosis. Our study suggests that sickle cell disease produces similar lesions in patients with sickle cell nephropathy.

Efficacy of cyclophosphamide in steroid-sensitive childhood nephrotic syndrome with different morphological lesions

We have reviewed the efficacy of cyclophosphamide in 39 steroid-sensitive frequently relapsing nephrotic children. Cyclophosphamide was used because of heavy steroid dependence and steroid toxicity. A percutaneous renal biopsy done prior to administration of cyclophosphamide showed the lesion to be minimal change in 7 children, IgM nephropathy in 17 children, and evolving from minimal change nephrotic syndrome to focal segmental sclerosis (FSGS) in 15 children. 100% of patients with minimal change nephrotic syndrome responded to cyclophosphamide, but only 58% of IgM patients responded (p less than 0.05). Only 1 of 15 FSGS patients responded (p less than 0.001 vs. minimal change nephrotic syndrome and p less than 0.01 vs. IgM). In view of the failure of cyclophosphamide to produce a remission in FSGS and its potential for long-term impairment of suppressor T cell function, we suggest that it should not be used in patients whose disease has evolved from minimal change to FSGS.

Acute renal failure as the initial manifestation of systemic lupus erythematosus in children

In two patients with systemic lupus erythematosus, acute renal failure was the initial manifestation. The diagnosis was eventually established on the basis of serologic tests and characteristic renal histopathologic findings. We emphasize the need to consider systemic lupus erythematosus as a cause of acute renal failure of glomerular origin, because appropriate therapy may alter the outcome of the disease.

Collagen-induced and adjuvant-induced arthritis in rats. Post-immunization treatment with collagen to suppress or abrogate the arthritic response

Immunization of Lewis rats with native type II collagen results in an inflammatory arthritis and increased humoral and cellular immune responses to type II collagen. The exposure of rats to native type II collagen at day 7 or 10 after immunization suppressed the incidence of arthritis and anticollagen antibody levels, although the cellular response was not affected. The exposure to denatured type II collagen offered partial protection, while type I collagen had no significant effect. Rats immunized with Mycobacterium tuberculosis also showed reduced arthritic response when subsequently treated with type II collagen. The common modalities between the 2 models and the possible role of type II collagen in the interference with the inflammatory arthritic events are discussed.

Autoreactivity to collagen in a murine lupus model

MRL/l mice exhibit many characteristics of human systemic lupus erythematosus including antinuclear antibodies, circulating immune complexes, glomerulonephritis, and death secondary to renal failure. In addition, these mice have elevated levels of rheumatoid factor and spontaneously develop arthritis that has many similarities to human rheumatoid arthritis. Our present studies indicate that, with age, they also develop reactivity to types I and II collagen. The levels of antibodies against native or denatured types I and II collagen in the sera of 4-5-month-old MRL/l mice are significantly higher than those in the sera of age-matched Balb/c or MRL/n mice. The specificity of these antibodies for collagen was demonstrated by a competitive binding assay. The T cells from 1- or 2-month-old MRL/l mice exhibited a significant proliferative response in the presence of type I collagen and a mild or no response to type II collagen. Both antigenic and mitogenic responses decreased with age. The results suggest that the development of autoimmunity to collagen may play an important role in the perpetuation of arthritis, vasculitis, and glomerulonephritis in MRL/l mice.

Familial focal segmental glomerulosclerosis

We have observed the nephrotic syndrome in more than one sibling in three unrelated hispanic families. The histological lesion in the involved children was either focal segmental glomerulosclerosis or IgM nephropathy evolving into focal sclerosis. Tissue typing revealed the presence of HLA DRw8 in six out of eight patients. The frequency of this antigen in our patients, when compared with its frequency in a group of unrelated normal hispanic children was highly significant (p less than 0.0001). Our study suggests that there may be a genetic predilection towards developing focal segmental glomerulosclerosis.

Regulation of metabolism of the chondrocytes in articular cartilage--an hypothesis

Over a number of years, researchers in many laboratories have studied the changes occurring in an osteoarthritic joint. Most of these studies involved the biomechanical properties of the joint, biochemistry and physiology of cartilage as a whole tissue or at the cellular level. As the involvement of cartilage in the early stages of osteoarthritis is of focal nature, the results of these various studies have been conflicting. Until recently, the chondrocytes were not assigned a major role in the degradation of cartilage matrix. Instead, the matrix-destruction was believed to occur by mechanical attrition. In this paper we discuss the changes occurring in the osteoarthritic joint and provide an hypothesis for understanding the interactions between inflammatory cells and the chondrocytes, leading to an altered metabolism of chondrocytes and loss of cartilage structure.

Secretion of chondrocyte stimulating factor by macrophages as a result of activation with collagen and proteoglycans

In this study, we have investigated the role of extracellular matrix components of connective tissue, collagen and proteoglycans, in the activation of rabbit macrophages and articular chondrocytes. Addition of type II collagen, in native or denatured form, or proteoglycan subunits, led to the activation of macrophages and release of chondrocyte stimulating factor. Type I collagen, when used at higher concentrations, was also capable of macrophage activation. The conditioned media of activated macrophages induced an increased protease synthesis by chondrocytes. Collagen or proteoglycan subunits did not have any direct stimulatory effect on chondrocytes. Intraperitoneal injections of collagen induced infiltration of macrophages into the peritoneal cavity. Although these macrophages failed to produce significant levels of chondrocyte stimulating factor by themselves, they could be activated in culture with lipopolysaccharides or collagen to produce chondrocyte stimulating factor. The chondrocytes, treated with the conditioned medium of activated macrophages (with lipopolysaccharides or cartilage matrix components), failed to survive in suspension cultures.

Long-term evaluation of children with nephrotic syndrome and focal segmental glomerular sclerosis

We studied the long-term outcome of a group of children with the nephrotic syndrome who showed the histological lesion of focal segmental glomerular sclerosis (FSGS) during the course of their illness. Of 25 such children studied, a complete follow-up ranging from 3 to 19 years was available in 24. Two distinct groups could be identified. Patients in the first group were characterized by steroid resistance (SR) from the onset, whereas those in the second group were initially steroid sensitive (SS), and had the histological lesion of minimal change which, over time, evolved into FSGS. SR patients had a mean age of 7.7 +/- 3.7 years compared to SS patients who were 3.5 +/- 2.5 years old (p less than 0.01). There were more females (11 of 14) in the SR group than in the SS group (3 of 10; p less than 0.02). The incidence of hematuria was higher in the SR patients (9 of 14) than SS patients (2 of 10; p less than 0.05). SR patients also exhibited a greater degree of growth retardation at the end of the follow-up period (9 of 13 compared to 1 of 8 SS patients; p less than 0.02). SR patients reached end-stage renal failure earlier (2.3 +/- 1.3 years) than SS patients (10 +/- 5.8 years; p less than 0.01) after the initial biopsy. Of the 13 kidney transplanted into 9 SR patients, recurrence of FSGS was noted in two allografts. Of the 4 kidneys transplanted into 2 SS patients, recurrence was seen in 1. The overall recurrence rate of FSGS in allografts was 17.6%. Our study suggests that the two varieties of FSGS occurring in nephrotic patients may be distinct nosologic entities rather than a single disease with varied manifestations.

Effects of various anti-inflammatory drugs on type II collagen-induced arthritis in rats

The effects of some commonly used anti-inflammatory and anti-arthritic drugs on the inflammatory and immunological manifestations of type II collagen-induced arthritis in rats were studied. Among the anti-inflammatory drugs tested at a given dosage (mg/kg/day), benoxaprofen (10), aspirin (25) and indomethacin (3) inhibited the hind paw swelling and anti-type II collagen antibody formation in type II collagen-treated rats. Benoxaprofen also inhibited the delayed type hypersensitivity (DTH) response to type II collagen. Phenylbutazone (30) and fenoprofen (40) partially suppressed the paw swelling, but had no significant effect on humoral and cellular responses. Among the other anti-arthritic drugs, levamisol (25), chloroquine (25) and D-penicillamine significantly suppressed the paw swelling, anti-type II collagen antibody titres and DTH response. Gold chlorophosphene (10) and colchicine (3) had no effect on any of these three parameters. Paramethasone (0.1), cyclophosphamide (1) and azathioprine (10) were very effective when dosed daily, or once (at a different dose) 72 hr prior to immunization with type II collagen.

The "hot spleen" phenomenon in metastatic malignant melanoma: its incidence and relationship with the immune system

Of patients with Stage II and III malignant melanoma, 34.7% display reversal of the liver-spleen ratio on technetium-99m-sulphur colloid isotope scans. Such an occurrence does not suggest a greater likelihood of relapse or a worse survival. The phenomenom is more common in female patients and there is a significant relationship between the presence of a "hot spleen" and a high IgM level. Patients with Stage II disease and high IgM levels have relapses more quickly than do those with normal IgM levels. Lymphopenia is common in patients with Stage II and III disease and the survival of these patients is worse than that of those with normal lymphocyte counts. In this report, the data are discussed together with results from other investigations, and a unifying hypothesis is presented which explains the phenomenon and relates it to increased activity of macrophages as a result of the presence of the tumor. The usefulness of isotope liver scanning in stage III malignant melanoma is also discussed.

Release of chondrocyte-stimulating factor by rabbit peritoneal macrophages

Cultured rabbit peritoneal macrophages, after stimulation with lipopolysaccharides (LPS), produce a factor that induces normal rabbit articular cartilage cells (chondrocytes) to release collagenase and other neutral proteases in their culture medium. The release of the factor as well as the activation of chondrocytes can be significantly inhibited by paramethasone (10(-6) M). Rabbit peripheral blood monocytes produce this factor in smaller quantities. Activation with LPS does not enhance the release of factor any further by these cells. Lymphocytes have no direct effect on the chondrocytic protease synthesis. Furthermore, conditioned medium of activated lymphocytes failed to stimulate monocytes or macrophages in the absence of LPS. The macrophage medium exhibits mitogenic and phytohaemagglutinin-enhancing activity towards thymocytes of C3H/HeJ mice, but not against species-specific rabbit lymphocytes. The lymphocyte-activating factor, derived from a mouse macrophage cell line, P388D1 cells, or from other sources, was unable to stimulate chondrocytic protease secretion. Such specific induction of chondrocytic proteases by a macrophage-derived factor may have an important role in cartilage destruction in arthritic conditions, where synovium is only marginally involved.

Platelet dysfunction in myeloproliferative syndromes

The most common abnormality of the platelets in 43 patients with a variety of myeloproliferative syndromes was impaired or absent aggregation when stimulated with collagen and adrenaline. Eight unselected cases studied in more detail showed a normal prostaglandin synthesis pathway as evidenced by normal aggregation with arachidonic acid and the production of normal amounts of malonyldialdehyde. Mixing experiments with aspirin-tested platelets showed correction of the abnormal adrenaline and collagen responses and confirmed that the nature of the defect was different from that induced by aspirin. Stimulation of "myeloproliferative" platelets with thrombin after blocking the prostaglandin pathway with aspirin resulted in reduced aggregation, indicating either a deficiency of the storage pool of adenine nucleotides in the platelets or an abnormality of a membrane receptor for thrombin.