Lipid Perxidtion and Antioxidants in Continuous Ambulatory Dialysis Patients

Objective

Oxidative cell damage due to the production of free radical species has been implicated in the pathogenesis of cardiovascular disease for which dialysis patients are at increased risk. Plasma lipid peroxides (malon-dialdehyde), the antioxidants plasma albumin thiol, and red cell superoxide dismutase (SOD) were therefore measured in 18 patients undergoing continuous ambulatory peritoneal dialysis (CAPD), 20 hemodialysis patients, and 30 normal controls.

Setting

Renal dialysis unit.

Results

Malondialdehyde(MDA)concentrationswere significantly higher in dialysis patients compared to controls (p<0.001 ) and were significantly higher in CAPD patients compared to hemodialysis patients, p<0.001 (CAPD, median and range: 11.25 (8.4–15.5) nmol/mL; hemodialysis: 8.75 (7.0–12.6) nmol/mL; controls: 6.65 (5.2–9.6) nmol/mL). Plasma thiol and red cell SOD were significantly lower in dialysis patients compared to controls, but there was no significant difference between CAPD and hemodialysis patients (CAPD thiol: 333.5 (282480) μmol/L; hemodialysis thiol: 344 (203–468) μmol/L; control thiol: 421.5 (351 -504) μmol/L; CAPD SOD: 78.2 (42.4 -112.8) u//2 mL red cells; hemodialysis SOD: 89.4 (44.6–121.1) u//2 mL red cells; control SOD: 96.8 (66.8153.4) u//2 mL red cells). Red cell SOD was significantly negatively correlated with duration of dialysis in CAPD patients (r=-0.683, p<0.01 ).

Conclusion

In dialysis patients there is indirect evidence for increased free radical activity, which may be further influenced by the mode of dialysis.

A rare case of ovarian carcinoid causing heart failure

Carcinoid tumours are rare tumours of the neuro-endocrine system. They most commonly present in the gut; however, they can present in other organs. In all, 0.3% of carcinoid tumours are ovarian in origin. Subsequently, very few cases of ovarian carcinoid affecting the heart have been reported and this case adds to the literature on this. There are very few reports in the literature of ovarian carcinoid and even fewer on cardiac failure due to carcinoid. Generally, carcinoid heart disease only affects the right-sided valves, sparing the mitral and aortic valves. We present the case of a patient who had an ovarian carcinoid tumour excised successfully and had been asymptomatic for 14 years prior to an incidental finding of right valvular signs on echocardiography, before subsequently right heart failure deemed to be secondary to ovarian carcinoid heart disease. The diagnosis is generally made on the findings of right-sided heart failure and the valvular abnormalities on echocardiogram (isolated pulmonary and tricuspid involvement). If the tumour is present at the same time as the development of heart failure, cardiac function can improve with timely tumour resection; however, cardiac disease can occur despite tumour removal.

Clinical and immunological analysis of melanoma patients receiving immunization using particle-mediated gene transfer of genes for gp100 and GM-CSF into uninvolved skin

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Background: To investigate a new method of activating melanoma-specific immune responses, we examined in vivo particle-mediated gene transfer (PMGT) of cDNAs for gp100 and GM-CSF into uninvolved skin of melanoma patients (pts). We now report the analysis of a completed Phase I clinical study. Methods: Two treatment groups of 6 pts each were evaluated. Group I received PMGT with cDNA for gp100 during each 3 week cycle; Group II received PMGT with cDNA for GM-CSF followed 3 days later by PMGT for gp100 at the same site. PMGT used 0.25 ug DNA and 250 ug gold/treatment. Endpoints included vaccine toxicity, transgene expression, immunological activation, and antitumor effects. Results: No systemic toxicity could be attributed to the vaccines, while local toxicity in both groups included mild erythema and induration which resolved within 2 weeks. Monitoring for autoimmunity showed no induction of pathologic autoantibodies. Biopsies of vaccine sites obtained 2 days after the gp100 PMGT showed 16% of gold beads to be in the dermis in Group I vs 3% in Group II, suggesting the prior GM-CSF PMGT inhibited bead penetration (p < 0.001 by chi-square; each bead penetration was analyzed as an independent event). Biopsies in Group I obtained 2 days after vaccination showed 16% of beads in the dermis vs 22% after 4 days (p < 0.001 by chi-square; each bead penetration was analyzed as an independent event). Transgene expression in vaccinated skin sites was detected by ELISA (GM-CSF) and IHC (gp100). One of 4 HLA-A2+ subjects showed a 5 × 5-mm DTH response to gp100 peptide 210M after Cycle 1. Preliminary in vitro studies suggest minimal immunological activation. Of 4 pts who enrolled with no evidence of disease, 2 remain disease-free after 61–73 months of follow-up. Conclusions: PMGT with cDNA for gp100 and GM-CSF yields transgene expression in normal human skin with minimal local or systemic toxicity. Pathologic autoimmunity was not demonstrated. Bead concentration in the dermis increases over time, suggesting persistence of beads in this skin level. Conclusions related to melanoma-specific immune induction await T-cell and antibody studies. Supported in part by the UW General Clinical Research Center (M01 RR03186).

No significant financial relationships to disclose.

The structure of phosphorylated GSK-3beta complexed with a peptide, FRATtide, that inhibits beta-catenin phosphorylation

BACKGROUND

Glycogen synthase kinase-3 (GSK-3) sequentially phosphorylates four serine residues on glycogen synthase (GS), in the sequence SxxxSxxxSxxx-SxxxS(p), by recognizing and phosphorylating the first serine in the sequence motif SxxxS(P) (where S(p) represents a phosphoserine). FRATtide (a peptide derived from a GSK-3 binding protein) binds to GSK-3 and blocks GSK-3 from interacting with Axin. This inhibits the Axin-dependent phosphorylation of beta-catenin by GSK-3.

RESULTS

Structures of uncomplexed Tyr216 phosphorylated GSK-3beta and of its complex with a peptide and a sulfate ion both show the activation loop adopting a conformation similar to that in the phosphorylated and active forms of the related kinases CDK2 and ERK2. The sulfate ion, adjacent to Val214 on the activation loop, represents the binding site for the phosphoserine residue on 'primed' substrates. The peptide FRATtide forms a helix-turn-helix motif in binding to the C-terminal lobe of the kinase domain; the FRATtide binding site is close to, but does not obstruct, the substrate binding channel of GSK-3. FRATtide (and FRAT1) does not inhibit the activity of GSK-3 toward GS.

CONCLUSIONS

The Axin binding site on GSK-3 presumably overlaps with that for FRATtide; its proximity to the active site explains how Axin may act as a scaffold protein promoting beta-catenin phosphorylation. Tyrosine 216 phosphorylation can induce an active conformation in the activation loop. Pre-phosphorylated substrate peptides can be modeled into the active site of the enzyme, with the P1 residue occupying a pocket partially formed by phosphotyrosine 216 and the P4 phosphoserine occupying the 'primed' binding site.

Mutation of histidine 286 of the human P2X4 purinoceptor removes extracellular pH sensitivity

1. Effects of external pH on the human P2X4 purinoceptor, an ATP-activated ion channel, were studied using the Xenopus oocyte expression system. 2. Changing the external pH from 7.4 to 6.5 significantly reduced, whilst an increase to pH 8 enhanced, maximum ATP-activated current amplitude, without changing the current- voltage relationship of the ATP-activated current. 3. Diethyl pyrocarbonate (DEPC; 10 mM) treatment of P2X4-injected oocytes had no effect on the pH sensitivity of the ATP-activated current. 4. Site-directed mutagenesis of histidine 286 (H286) to alanine completely abolished the pH sensitivity of the P2X4 receptor at all agonist concentrations. ATP potency showed a small (fourfold) leftward shift. Mutagenesis of the other three histidines present in the P2X4 sequence had no effect on pH sensitivity. 5. The results show that pH modulation of P2X4 in the pathophysiological range is mediated by protonation of H286. This provides direct confirmation that pH sensitivity resides in the P2X4 channel protein rather than the agonist species.

Blockade of the MAP kinase pathway suppresses growth of colon tumors in vivo

The mitogen-activated protein kinase pathway is thought to be essential in cellular growth and differentiation. Here we report the discovery of a highly potent and selective inhibitor of the upstream kinase MEK that is orally active. Tumor growth was inhibited as much as 80% in mice with colon carcinomas of both mouse and human origin after treatment with this inhibitor. Efficacy was achieved with a wide range of doses with no signs of toxicity, and correlated with a reduction in the levels of activated mitogen-activated protein kinase in excised tumors. These data indicate that MEK inhibitors represent a promising, noncytotoxic approach to the clinical management of colon cancer.

Identification of the binding site on cytochrome P450 2B4 for cytochrome b5 and cytochrome P450 reductase

A model of cytochrome P450 2B4, which was constructed by homology modeling with the four known crystal structures of the cytochromes P450 (Chang, T.-T., Stiffelman, O. B., Vakser, I. A., Loew, G. H., Bridges, A., and Waskell, L. (1997) Protein Eng. 10, 119-129), was used to select amino acids predicted, by computer docking studies and numerous previous biochemical and site-directed mutagenesis studies, to be involved in binding the heme domain of cytochrome b5. Twenty-four amino acid residues located on both the distal and the proximal surface of the molecule were chosen for mutagenesis. These 24 mutant proteins were expressed in Escherichia coli, purified, and characterized with respect to their ability to bind cytochrome b5 and support substrate oxidation. Seven mutants, R122A, R126A, R133A, F135A, M137A, K139A, and K433A, all on the proximal surface of cytochrome P450 2B4 near the heme ligand, were identified that exhibited decreased ability to bind cytochrome b5. All of the mutants except K433A are located in either the C or C* helices or their termini. In addition, these seven mutants and two additional mutants on the proximal surface of cytochrome P450, R422A and R443A, were shown to exhibit decreased binding to cytochrome P450 reductase. These studies indicate that the binding sites for cytochrome b5 and cytochrome P450 reductase are, as predicted, located on the proximal surface of cytochrome P450 2B4 and are partially overlapping but not identical.

Neutralizing epitopes on the extracellular interferon gamma receptor (IFNgammaR) alpha-chain characterized by homolog scanning mutagenesis and X-ray crystal structure of the A6 fab-IFNgammaR1-108 complex

The extracellular interferon gamma receptor alpha-chain comprises two immunoglobulin-like domains, each with fibronectin type-III topology, which are responsible for binding interferon gamma at the cell surface. The epitopes on the human receptor recognized by three neutralizing antibodies, A6, gammaR38 and gammaR99, have been mapped by homolog scanning mutagenesis. In this way, a loop connecting beta-strands C and C' in the N-terminal domain was identified as a key component of the epitopes bound by A6 and gammaR38, whereas gammaR99 binds to the C-terminal domain in a region including strands A and B and part of the large C'E loop. The epitope for A6 was confirmed in a crystal structure of a complex between a recombinant N-terminal receptor domain and the Fab fragment from A6, determined by X-ray diffraction to 2.8 A resolution. The antibody-antigen interface buries 1662 A2 of protein surface, including 22 antibody residues from five complementarity determining regions, primarily through interactions with the CC' surface loop of the receptor. The floor of the antigen binding cavity is formed mainly by residues from CDR L3 and CDR H3 while a surrounding ridge is formed by residues from all other CDRs except L2. Many potential polar interactions, as well as 13 aromatic side-chains, four in VL, six in VH and three in the receptor, are situated at the interface. The surface of the receptor contacted by A6 overlaps to a large extent with that contacted by interferon-gamma, in the ligand-receptor complex. However, the conformation of this epitope is very different in the two complexes, demonstrating that conformational mobility in a surface loop on this cytokine receptor permits steric and electrostatic complementarity to two quite differently shaped binding sites.

Construction of a 3D model of cytochrome P450 2B4

A three-dimensional structural model of rabbit phenobarbital-inducible cytochrome P450 2B4 (LM2) was constructed by homology modeling techniques previously developed for building and evaluating a 3D model of the cytochrome P450choP isozyme. Four templates with known crystal structures including cytochrome P450cam, terp, BM-3 and eryF were used in multiple sequence alignments and construction of the cytochrome P450 2B4 coordinates. The model was evaluated for its overall quality using available protein analysis programs and found to be satisfactory. The model structure was stable at room temperature during a 140 ps unconstrained full protein molecular dynamics simulation. A putative substrate access channel and binding site were identified. Two different substrates, benzphetamine and androstenedione, that are metabolized by cytochrome P450 2B4 with pronounced product specificity were docked into the putative binding site. Two orientations were found for each substrate that could lead to the observed preferred products. Using a geometric fit method three regions on the surface of the model cytochrome P450 structure were identified as possible sites for interaction with cytochrome b5, a redox partner of P450 2B4. Residues that may interact with the substrates and with cytochrome b5 have been identified and mutagenesis studies are currently in progress.

Nursing education resources on the World Wide Web

The Internet offers the promise of quick and convenient access to large amounts of up-to-date information. There are many resources on the Internet for nurses and nurse educators, but they can be challenging to locate and the information must be evaluated carefully. In this article, some nursing resources on the Internet are analyzed and criteria for evaluating information are suggested. With a little patience and persistence, nurse educators will find exploring the Internet rewarding and informative.

Production and characterization of anti-human interferon gamma receptor antibody fragments that inhibit cytokine binding to the receptor

Three single-chain antibody fragments that recognize the extracellular human interferon gamma receptor alpha-chain (IFN gamma R), and inhibit the binding of human IFN gamma, have been produced in Escherichia coli. These fragments are derived from murine anti-receptor monoclonal antibodies, and comprise the variable heavy (VH) domain linked to the variable light (VL) chain through a 15 amino acid linker [(GGGGS)3]. Using surface plasmon resonance technology (BIAcore), the soluble proteins were shown to retain a high affinity for recombinant IFN gamma R, and by radioimmunoassay to possess a high inhibitory activity towards IFN gamma-binding to human Raji cells. The antibody fragments most likely recognize epitopes that overlap the cytokine binding site on the receptor surface. Attempts to dissect further the antibodies to isolated VH- and VL-chains and to synthetic linear and cyclic peptides derived from the individual complementarity determining regions failed to afford fragments with significant IFN gamma R binding affinity. Nevertheless, these native-like variable region fragments and petidomimetics derived from them are of interest in the design of novel IFN gamma R antagonists.

Variable region cDNA sequences and characterization of murine anti-human interferon gamma receptor monoclonal antibodies that inhibit receptor binding by interferon gamma

Murine monoclonal antibodies (mAbs) are described that recognize the extracellular human interferon gamma receptor alpha-chain (IFN gamma R) and inhibit the binding to it of interferon gamma. The inhibitory activities (IC50s) of these mAbs, quantified by radioimmunoassay using native receptor on human Raji cells, lie in the range 0.5-24 nM, whereas their relative affinities for the immobilised recombinant extracellular receptor, determined using surface plasmon resonance technology, are in the range 0.6-40.9 nM. Nine mAbs derived from one immunization, were shown by variable region cDNA sequencing to be clonally related, with mAb A6 from this group showing the highest affinity for the receptor. Another two mAbs, gamma R38 and gamma R99, derived from a separate immunization, are clonally unrelated to each other and to those in the A6 family. From the V-region sequences, the L-chains of mAbs A6, gamma R38 and gamma R99 were shown to belong to the V kappa 34C, V kappa 34C and V kappa 1 families, whereas the H-chains belong to the 3069, J606 and J558 families, respectively. The mAbs A6 and gamma R38 recognize overlapping epitopes on the N-terminal Ig-like domain of the IFN gamma R, whereas the gamma R99 epitope is located largely in the membrane proximal Ig-like domain. Sequence comparisons with Ig structures solved by X-ray diffraction allowed deductions concerning likely CDR canonical conformations. These studies provide essential information for crystallographic and mutagenesis experiments aimed at understanding the molecular basis of the interactions of these mAbs with the extracellular IFN gamma R.

Family history of severe cardiovascular disease in Marfan syndrome is associated with increased aortic diameter and decreased survival

OBJECTIVES

We attempted to determine whether a family history of severe cardiovascular disease in patients with the Marfan syndrome is associated with increased aortic dilation or decreased survival, or both.

BACKGROUND

The prognostic importance of a family history of severe cardiovascular disease in patients with the Marfan syndrome has been incompletely examined. We hypothesized that such a family history would correlate with increased aortic dilation and would be associated with decreased survival.

METHODS

One hundred eight affected patients and 48 unaffected family members from 33 multigenerational families with the Marfan syndrome underwent echocardiographic measurement of the aortic root, arch and mid-abdominal aorta. Date of birth and age at death ascertained from family pedigrees were used to perform life table analysis and estimate survival.

RESULTS

Aortic root and arch diameters were significantly greater in patients with a family history of severe cardiovascular disease than in patients without such a family history. Of subjects in the highest quartile for aortic size, > 80% had such a family history in contrast to < 10% of those in the lowest quartile (chi-square 57.37, p < 0.00001). Mean age at death and cumulative probability of survival were significantly lower in patients with such a family history.

CONCLUSIONS

Among patients with the Marfan syndrome, aortic dilation is greater and life expectancy shorter in those with a family history of severe cardiovascular manifestations. These data suggest that such a family history is an important risk factor for cardiovascular events in patients with the Marfan syndrome.

Effects of captopril and enalapril on renal function in elderly patients with chronic heart failure

OBJECTIVE

To compare the effects on renal function of captopril and enalapril in elderly patients with chronic heart failure.

DESIGN

A multi-centre double-blind parallel-group comparison of the two angiotensin-converting enzyme (ACE) inhibitors, captopril (12.5 mg bid) and enalapril (2.5 mg bid).

SUBJECTS

80 elderly patients with chronic heart failure (41 in the captopril group, 39 in the enalapril group).

MAIN OUTCOME MEASURES

The blood pressure and pulse rate response to the first dose of ACE inhibitor was assessed in all patients. Glomerular filtration rate (GFR) was measured radioisotopically by 99mTcDTPA or 51CrEDTA clearance after three and six months of each treatment. Subgroups were assessed for effective renal plasma flow (33 patients), exercise tolerance (25 patients) and by a symptom-oriented questionnaire (45 patients).

RESULTS

No serious adverse effect on GFR was noticed. There was no significant difference between the two treatments in the mean baseline GFR or in changes from baseline at three and six months (captopril mean baseline GFR 49.6 ml min-1 1.76 m-2, enalapril 54.7 ml min-1 1.76 m-2; mean change (95% confidence interval) at three months captopril 12 ml min-1 (+3.0, +21.0), enalapril -2 ml min-1 (-13.0; +9.0); mean change at six months, captopril 3.7 ml min-1 (-6.7; +14.2), enalapril -6.0 ml min-1 (-21.0; +9.4). Significantly more patients given captopril had an improvement in GFR during the study period (26/31 compared with 20/31 enalapril-treated patients at three months, p = 0.0096, and 23/30 compared with 15/27 at six months, p = 0.021). There were no significant changes in effective renal plasma flow. Three patients treated with enalapril developed symptomatic hypotension within three days of starting treatment. Quality of life questionnaires revealed more gastrointestinal symptoms in the enalapril group (p = 0.039).

CONCLUSIONS

Captopril seems marginally preferable to enalapril in the treatment of chronic heart failure in elderly patients.

Hearing impairment and ear pathology in Nepal

A stratified random cluster sample of 15,845 subjects was performed in two regions of Nepal to determine the prevalence and main causes of hearing impairment (the most common disability) and the prevalence of ear disease. Subjects reporting current ear pain, or ear discharge, or hearing impairment on direct questioning by a Nepali health worker (primary screening failed), had otoscopy and audiometry (using the Liverpool Field Audiometer) performed, and a questionnaire administered relating to past history. In every fifth house subjects who passed the primary screening (1,716 subjects) were examined to assess the false negative rate of screening. An estimated 16.6 per cent of the study population have hearing impairment (either ear worse than 30 dB hearing threshold level (HTL) 1.0-4.0 kHz, or 50 dB HTL 0.5 kHz), and 7.4 per cent ear drum pathology, equivalent to respectively 2.71 and 1.48 million people extrapolated to the whole of Nepal. Most hearing impairment in the school age group (55.2 per cent) is associated with otitis media or its sequelae. Probably at least 14 per cent of sensorineural deafness is preventable (7 per cent infectious disease, 3.9 per cent trauma, 0.8 per cent noise exposure, 1 per cent cretinism, and 1 per cent abnormal pregnancy or labour). Most individuals reporting current ear pathology (61 per cent) had never attended a health post, and of those receiving ear drop treatment, 84 per cent still had serious pathology. Of subjects who reported ear drop treatment at any time, 31 per cent still had serious pathology. The use of traditional remedies was prevalent.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxygen free radicals and platelet and granulocyte aggregability in renal transplant patients

Oxygen free radical reaction products (plasma malondialdehyde), the free radical scavengers plasma thiol and red cell superoxide dismutase (SOD), and whole blood platelet and granulocyte aggregation were measured in 23 renal transplant patients and 23 age-matched controls. Malondialdehyde-like material (MDA) was significantly increased in transplant patients compared with controls (transplants MDA [median, range], 7.7 [5.3-11.5] nmol/ml; controls MDA, 6.3 [5.4-8.7] nmol/ml; P < 0.001). The patients also had increased red cell superoxide dismutase (transplants SOD, 128.1 [89.4-93.8] U/0.5 ml red cells; controls SOD, 95.9 [62.0-132.6] U/0.5 ml red cells; P < 0.001) and reduced plasma thiol (transplants thiol, 428 [266-496] mumol/L; controls thiol, 445 [358-501] mumol/L; P < 0.05). These factors were not influenced by immunosuppressive therapy, duration of transplantation, or creatinine concentration. Transplant patients had significantly higher levels of collagen-induced and spontaneous whole blood platelet aggregation compared with controls (collagen: transplants, 72 [4-93%]; controls 43 [6-94]%; P < 0.001; spontaneous: transplants 46 [11-93]%; controls 37 [10-75]%; P < 0.05). Spontaneous platelet aggregation, however, was significantly correlated with creatinine concentration (r = 0.525, P < 0.02, Spearman's correlation), and was raised only in those patients with a degree of renal impairment. Granulocyte aggregation was increased in patients receiving cyclosporine (CsA [n = 15], 57 [36-66]%; no cyclosporine [n = 8], 45 [37-62]%; controls [n = 23]; 39 [31-61]%; P = 0.004). Renal transplant patients are subject to oxidative cell damage, and may be at increased risk of vascular thrombosis. Possible contributory factors include an immunological reaction to the graft and/or the effects of immunosuppressive therapy.

Relationship of changes in helplessness and depression to disease activity in rheumatoid arthritis

We investigated the relationship between changes in helplessness and depression to disease activity in rheumatoid arthritis (RA). Sixty-three men with RA were examined at baseline, 3 months, and 6 months. Joint counts, immunophenotypic analyses of peripheral blood lymphocytes, and measures of psychological status were obtained at each examination. Zero-order correlations between psychological change and disease activity change from baseline to 6 months were not significant, but hierarchical multiple regression analyses revealed that changes in affective state were significantly related to joint counts at 6 months. Additionally, changes in absolute numbers of HLA-DR+ (human leukocyte antigen DR type) cells were significantly related to joint counts at 6 months. When absolute numbers of HLA-DR+ cells were entered prior to affective state in a hierarchical multiple regression, affective state was only marginally statistically significant. The study shows that longitudinal relationships between affective changes and disease activity are moderated by intervening variables such as immunologic activation.

Practical issues when initiating captopril therapy in chronic heart failure. What is the appropriate dose and how long should patients be observed?

To assess the feasibility of introducing captopril in patients with chronic heart failure on an outpatient rather than an inpatient basis a double-blind placebo-controlled study was carried out to compare either 6.25 mg or 25.0 mg of captopril as a starting dose; followed by either incremental doses of 6.25, 12.5, and 25.0 mg (low dose group), or 25.0 mg 8 hourly (high dose group) respectively. Forty-one patients in a general medical ward within a large teaching hospital with moderate to severe, stable, diuretic-controlled chronic heart failure, who were not hyponatraemic, hypokalaemic or on a dose of diuretic greater than 120 mg of frusemide took part. No patient experienced symptomatic hypotension. Both doses of captopril produced a significant drop in blood pressure (BP), the magnitude of which was similar in both groups. The first dose-induced fall correlated significantly with subsequent dose-related reductions in BP. Therefore if a patient did not have a hypotensive response to the first dose of captopril he/she would be unlikely to have one with subsequent doses. In the group as a whole, the magnitude of the fall in BP after the first dose correlated significantly with starting plasma levels of angiotensin II, atrial natriuretic peptide (ANP), aldosterone, and renin. However, on an individual basis, the two patients with the greatest fall in blood pressure did not have the most activated renin-angiotensin-aldosterone (RAA) system. This serves to emphasise the unpredictability of this response and the need to initiate therapy under clinical observation.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipyridamole increases human red blood cell deformability

An automated filtration technique has been used to investigate the effect of dipyridamole (DP) on red blood cell deformability in patients identified as having rigid red cells. They were patients on haemodialysis (HD) for chronic renal failure (n = 18), patients with peripheral vascular disease (PVD, n = 23) and controls (hospital outpatients, n = 33). Leucocytes and platelets were removed from heparinised blood by filtration through Imugard wool. Washed red cell suspensions in buffer at 5% haematocrit, without or with 5 microM DP, were filtered through Nuclepore Hemafil Membranes with 4.7 microns pores. The initial steady state relative filtration pressure (iRFP) was used to assess cell deformability. A low iRFP value reflects increased deformability and vice versa. The mean iRFP values were 0.33, 0.393 and 0.403 for controls, PVD and HD patients respectively, indicating that the red cells in the two groups of patients were significantly more rigid. DP reduced the iRFP to 0.266, 0.278 and 0.263 for controls, PVD and HD patients respectively. The results suggest that DP may be beneficial when red cell rigidity contributes to impaired microvascular perfusion.

Pneumocystis carinii pneumonia in patients with connective tissue disease

Four patients with PCP complicating a CTD are described. Rising serum lactate dehydrogenase levels were documented during an asymptomatic period associated with corticosteroid dosage tapering, weeks prior to the development of acute pulmonary symptoms. The diagnosis of PCP was established by FOB in each patient.

A linkage map of 10 loci flanking the Marfan syndrome locus on 15q: results of an International Consortium study

Members of an International Consortium for Linkage Analysis of the Marfan Syndrome (MFS1) have pooled data for joint analysis in an attempt to determine the precise location of the MFS1 gene and the order of 10 DNA markers on 15q. Five laboratories performed a total of 2111 genotypes in 22 families consisting of 225 affected and 248 normal subjects. For each marker a mean of 98 meioses was informative. D15S48 and D15S1 were identified as the closest linked markers with 99% upper confidence intervals of 12% and 13% respectively. We have used the CRI-MAP program to construct the most likely order as: D15S24-D15S25-D15S1-MFS1-D15S48-D15S49+ ++-(D15S45/S51)-(D15S29/S38). Placement of D15S2 in relation to -D15S1-D15S48- cannot be determined with certainty. The genetic map of these markers extends 53.6 cM in males and 65.0 cM in females with a sex averaged map of 60.7 cM. The sex difference was statistically significant (p = 0.005). Linkage heterogeneity between 22 MFS1 families was documented (p = 0.009) necessitating the exclusion of one family from the analysis. However, comparison of the remaining 21 families for two point and multipoint lod scores showed no evidence for linkage heterogeneity of the MFS1 locus.

Relative contributions of years since menopause, age, and weight to vertebral density in postmenopausal women

Vertebral mineral density (VMD) was measured by quantitative computerized tomography (QCT) in 16 premenopausal and 243 untreated postmenopausal women without vertebral compression. The mean VMD in the premenopausal group was 157 +/- 10.1 mg/mL, which is close to previously reported values. In the postmenopausal women, VMD fell significantly with age and years since menopause (YSM) separately and together, but the relation to YSM was more significant than that to age. After logarithmic transformation of YSM, the fall in bone density with logYSM was highly significant (P less than 0.001), and that with age was not quite significant. In 36 pairs of women matched for YSM, there was no significant difference in VMD between the subjects up to and over 55 yr of age. In 32 pairs matched for age, VMD was significantly lower in those over 55 yr than in those up to 55 yr (P = 0.005). There was also a significant correlation between VMD and body weight. After this was allowed for, the correlation between VMD and logYSM remained highly significant, but the correlation with age was not significant. We conclude that the fall in vertebral body trabecular bone in postmenopausal women is self-limiting, amounts to about 35% bone loss in 25 yr (most of it in the first 5 yr), and corresponds to but is proportionately greater than the trabecular component in postmenopausal forearm bone loss.

Whole blood granulocyte aggregation in vitro in dialysis-dependent patients

Whole blood granulocyte aggregation in vitro was measured in 17 haemodialysis (HD) patients, 18 continuous ambulatory peritoneal dialysis (CAPD) patients, and 30 age-matched normal controls. Granulocyte aggregation was significantly increased in dialysis-dependent patients compared to controls (P less than 0.001) and was statistically significantly higher in CAPD patients compared to HD patients (P less than 0.01). [CAPD patients, median (range): 56.5 (44-71)%; HD patients: 53.0 (32-67)%; Controls; 42.5 (33-56)%.] Since granulocyte hyperaggregability has been linked with the pathogenesis of ischaemic vascular disease, abnormal granulocyte activity in dialysis-dependent patients may be of many factors contributing to their increased cardiovascular morbidity.

Malabsorption of calcium in corticosteroid-induced osteoporosis

We have examined the relation between radiocalcium absorption and serum 1,25-dihydroxyvitamin D [1,25(OH)2D3] levels in a set of 60 postmenopausal women on corticosteroid therapy (29 with and 31 without vertebral compression fractures) and compared these results with those from 31 normal postmenopausal women age-matched with the "normal" corticosteroid-treated women. Radiocalcium absorption was a function of serum 1,25(OH)2D3 in both corticosteroid-treated groups and in the set as a whole, but the impaired calcium absorption in the corticosteroid-treated patients with osteoporosis was not accounted for by their slightly reduced serum 1,25(OH)2D3 levels. This apparent resistance to the intestinal action of 1,25(OH)2D3 was quantified by a Z score which expresses, in standard deviation units, the difference between the measured calcium absorption and that predicted from the 1,25(OH)2D3 level. The Z score was significantly reduced in the osteoporotic group. Vertebral mineral density (VMD) was measured by quantitative computed tomography in 43 of the corticosteroid-treated cases and in all the normal postmenopausal women; analysis by VMD yielded similar conclusions.

Oxidative damage in chronic heart failure: protection by captopril through free radical scavenging?

The pathogenesis of heart failure is not yet fully understood. In animal models there is some evidence to suggest a role for free radicals (FRs). We have investigated malondialdehyde - LM in plasma of patients with heart failure and found it to be raised when compared to controls. We present data to show that Captopril, a drug with an ACE inhibitory effect is a FR scavenger both in vitro and ex-vivo in patients with heart failure.

Pathogenicity of experimental infection with 'pneumotropic' porcine coronavirus

Virus localisation and lesions were studied in 14 one-week-old piglets following combined intranasal-oral inoculation with a British isolate of ‘pneumotropic’ porcine coronavirus (pcv) and were compared with the effects of transmissible gastroenteritis virus (tgev) infection in five piglets. Unlike TGEV-infected piglets, all pcv-inoculated piglets remained clinically healthy. Seroconversion was detected at seven days after inoculation. Mild bronchointerstitial pneumonia involving terminal airways was consistently present at two days after infection and thereafter. Both pcv and tgev infected bronchiolar epithelium and alveolar macrophages but, unlike tgev, replication by pcv in villous enterocytes was limited and did not cause villous atrophy.

Evaluation of monoclonal antibodies to K88, K99, F41 and 987P fimbrial adhesins for the detection of porcine enterotoxigenic Escherichia coli in paraffin-wax tissue sections

A panel of monoclonal antibodies against fimbrial adhesins of porcine enterotoxigenic Escherichia coli were evaluated for the detection of enteric colibacillosis in paraffin-wax embedded sections of piglet small intestine. Using the immunoperoxidase technique, monoclonal antibodies were used to detect epitopes on the K99 adhesin and on the a and c regions of the K88 adhesin. However, monoclonal antibodies to the F41 and 987P adhesins failed to react in sections with organisms colonising the intestine of gnotobiotic piglets monoinfected with strains bearing those adhesins, whereas corresponding polyclonal antisera gave positive results. In contrast to apparent expression of all K99 organisms, only a proportion of organisms were identified by monoclonal or polyclonal antibodies as expressing K88. In some instances, failure of immunostaining was attributed to prolonged storage of tissue in formalin.

Pathogenicity of experimental infection with 'pneumotropic' porcine coronavirus

Virus localisation and lesions were studied in 14-one-week-old piglets following combined intranasal-oral inoculation with a British isolate of 'pneumotropic' porcine coronavirus (PCV) and were compared with the effects of transmissible gastroenteritis virus (TGEV) infection in five piglets. Unlike TGEV-infected piglets, all PCV-inoculated piglets remained clinically healthy. Seroconversion was detected at seven days after inoculation. Mild bronchointerstitial pneumonia involving terminal airways was consistently present at two days after infection and thereafter. Both PCV and TGEV infected bronchiolar epithelium and alveolar macrophages but, unlike TGEV, replication by PCV in villous enterocytes was limited and did not cause villous atrophy.

Antigen-specific recognition of autologous leukemia cells and allogeneic class-I MHC antigens by IL-2-activated cytotoxic T cells from a patient with acute T-cell leukemia

Culturing of leukemic blood lymphocytes from a patient with acute T-cell lymphoblastic leukemia (T-ALL) with interleukin-2 (IL-2) yielded T-cell line AK-1 with a remarkable cytotoxic specificity. This line mediated strong lysis of tumor target lines expressing major histocompatibility complex (MHC) class I antigens, such as Raji, CEM, and Molt-4 cells, but no killing of K562 and Daudi cells, which are deficient in MHC class I. In contrast, lymphokine-activated killer (LAK) cells from normal donors destroyed all these tumor targets, without MHC restriction. Line AK-1, originating from residual normal T cells present in the leukemic blood, lysed autologous leukemic blasts and peripheral blood lymphocytes (PBL) from many but not all allogeneic individuals but failed to kill autologous remission lymphocytes. Destruction of the autologous leukemic targets by AK-1 could be inhibited by unlabeled competitor target cells that were lysed by AK-1, but not by target cells that were not lysed. This suggests that AK-1 specifically recognized an alien determinant on the autologous ALL cells, crossreactive with allogeneic MHC class I antigens. This reactivity with some degree of tumor specificity may be a leukemic equivalent to responses reported for populations of tumor infiltrating lymphocytes (TIL) seen in some solid tumors.

Captopril: a free radical scavenger

The use of captopril in heart failure and hypertension is becoming increasingly accepted. Captopril has a sulphydryl group in its molecular structure. We wondered if this might confer free radical scavenging activity on the drug and have investigated this in an in vitro system. Results show that captopril is a free radical scavenger and we suggest that this action might be relevant in its use in heart failure and other vascular diseases.

Effects of nandrolone decanoate and antiresorptive therapy on vertebral density in osteoporotic postmenopausal women

Conventional antiresorptive therapy for osteoporosis can delay bone loss, but secondary inhibition of bone formation appears to prevent an increase in bone density. Recently, anabolic steroid therapy has been shown to increase total body calcium and forearm density in osteoporotic patients, perhaps by causing an increase in bone formation. It is not known if these agents affect vertebral density. We have measured vertebral mineral density in 71 postmenopausal osteoporotic women before and after treatment with either the anabolic steroid nandrolone decanoate or antiresorptive therapy. After a mean treatment period of 14 months, there was a mean increase of 20% in vertebral mineral density in the former group, and no significant change in the latter group. The difference in the time-weighted mean rates of change between the two groups was significant. The results suggest that nandrolone decanoate therapy increases bone formation.

Familial type II protein C deficiency associated with warfarin-induced skin necrosis and bilateral adrenal hemorrhage

A family is described in which venous thromboembolic disease is associated with reduced plasma protein C activity and normal levels of protein C antigen. Immunoelectrophoretic analysis of protein C antigen gave an abnormal pattern in all affected members, suggesting that the disorder is related to the presence of a structurally and functionally abnormal form of protein C. The propositus developed simultaneous warfarin-induced skin necrosis and bilateral adrenal hemorrhage. This is the first reported instance of warfarin-induced skin necrosis associated with a dysfunctional protein C molecule and the first reported instance of simultaneous warfarin-induced skin necrosis and bilateral adrenal hemorrhage.

The relation between forearm and vertebral mineral density and fractures in postmenopausal women

Vertebral and forearm mineral density (VMD and FMD, respectively) were determined in 124 postmenopausal women with no crushed vertebrae or peripheral fractures, 51 who had sustained peripheral fractures only since the menopause, 62 with vertebral compression(s) only and 75 with both types of fracture. There was a very significant correlation between the two measurements in the whole set. The scatter could not be accounted for by methodological error but was partly accounted for by body weight, since VMD was related to body weight and FMD was not. Whatever criterion was used for the diagnosis of osteoporosis (whether fracture or density) the percentage of misclassified cases was very similar by the two methods. However, VMD was relatively more reduced than FMD in vertebral fracture cases and FMD was marginally more reduced than VMD in peripheral fracture cases. There is little to choose between vertebral and forearm density in the diagnosis of osteoporosis but vertebral densitometry is slightly superior to forearm densitometry in describing the severity of osteoporosis in vertebral fracture patients.

Cross-cultural aspects of sleep in the elderly

A sleep questionnaire (SQ) was administered to 850 adults, 50 years and older, drawn from urban areas in 7 countries (Australia, Greece, Italy, Mexico, Spain, Venezuela, United States). All were functioning adults in relatively good physical and mental health. The samples were equated on sex, age, and occupational level. Of the 8 scales on the SQ, 7 showed statistically significant differences between countries, and 3 between males and females. At the same time, substantial similarities were found and are discussed from a normative point of view.

The relation between calcium absorption, serum dehydroepiandrosterone, and vertebral mineral density in postmenopausal women

Vertebral mineral density, measured by computerized axial tomography, radiocalcium absorption, serum dehydroepiandrosterone (DHA), and serum cortisol (C) were measured in 98 postmenopausal women aged 56-70 yr. On the basis of spine radiographs and fracture history, the women were classified into 49 normal subjects (mean age, 60.5 yr) and 49 with osteoporosis (mean age, 63.1 yr). Vertebral mineral density (VMD), radiocalcium absorption (alpha), serum DHA, and the ratio of DHA to cortisol (DHA/C) were all significantly lower in the osteoporotic than in the normal subjects. DHA was significantly related to C in both groups but the regression was significantly flatter in the osteoporotic than in the normal subjects. Calcium absorption did not fall significantly with age in either group. In the normal group VMD, DHA, and DHA/C fell with age but VMD was not related to alpha, DHA, or DHA/C. In the osteoporotic group, VMD did not fall significantly with age but was significantly related to alpha and DHA/C. Stepwise regression analysis showed that in the normal subjects, age was the only variable significantly related to VMD (P less than 0.05). In the osteoporotic group, calcium absorption was the main determinant of VMD, with age and DHA/C contributing much less to the variance. Discriminant function analysis showed a theoretical misclassification of 45% of cases using DHA, 39% using DHA/C, 32% using alpha, and 18% when alpha and DHA or DHA/C were both taken into account. It is concluded that malabsorption of calcium is a significant risk factor for postmenopausal osteoporosis, probably because of a secondary increase in bone resorption to maintain serum calcium. The severity of the osteoporosis is directly related to the severity of the calcium malabsorption. Low serum DHA appears to represent a further risk factor, either because of its role as estrogen precursor or (possibly) because it promotes bone formation. However, the severity of the osteoporosis was not related to the serum DHA level and only weakly to the DHA/C ratio.

Preschool children's comprehension of agency

An acting-out task and two modified forms of the token-assignment task described by Braine & Wells (1978) were used to test the ability of 72 children aged 3;0–4;6 to identify the actor in an event; in one token-assignment task the children were required to respond after watching silent enactments of transitive events, and in the other the children heard verbal descriptions of similar events. Comparison of individual response patterns across the tasks revealed that whereas 62 of the 72 children could identify the actor in the non-verbal task, 19 of them subsequently failed to perform as well when they had to base their judgement on active sentences in the verbal task; and of the 44 who responded accurately in the verbal token-assignment task only 34 responded consistently correctly when required to act out those sentences. The results are discussed in terms of their implications for the development of syntactic comprehension.

Subjective assessment of sleep by Sleep Questionnaire

A 55-item Sleep Questionnaire is presented for possible use as a standardized instrument in psychological studies of sleep. A factor analysis of responses from 145 adults to the questionnaire indicated 7 factors accounted for 71.7% of the total variance. These factors are congruent with sleep dimensions discussed in the literature and with other factor analytic investigations. A set of 11 clinical judgment scales are also presented. The reliabilities of both factor and clinical scales are adequate as judged by test-retest, internal consistency, and comparisons of self vs spouse ratings. The construct validity is supported by three studies showing significant differences between (a) medical patients with and without sleep disturbances, (b) psychiatric patients with and without symptoms of depression, and (c) short and long sleepers.

Syntactic comprehension in Down's syndrome children

The ability of 24 Down's syndrome children to act out active and passive semantically biased and neutral sentences in a comprehension task was compared with that of 24 non-retarded children, matched on the basis of their verbal comprehension scores on the Reynell Developmental Language Scale (Reynell, 1969). Down's syndrome children closely resembled control children both in terms of percentage correct responses and in terms of individual children's patterns of error. The results are taken as support for the proposition that the processes underlying language comprehension in the retarded are fundamentally the same as those of non-retarded children. Even so, there was evidence of a slight (6 to 12 months) delay in the appearance of syntactic strategies of comprehension by the Down's syndrome children compared with those non-retarded children matched with them in terms of verbal comprehension age.

SVO comprehension strategies reconsidered: the evidence of individual patterns of response

Several researchers (e.g. Bever 1970, Strohner & Nelson 1974) have suggested that young children commonly employ a word-order strategy of the form: ‘the first mentioned participant is agent’ when interpreting active and passive sentences. Pre-school children (aged 2; 6–5; 0) were presented with reversible active and passive sentences in four comprehension test settings (two acting-out tasks, a selection task and a verification task). Their responses were analysed not in terms of the percentage correct responses for each group of subjects, as has been the usual practice, but in terms of each individual child's pattern of responses. The results revealed age-related changes in the type of response patterns found. The response pattern associated with the word-order strategy was not a frequent occurrence. The most common patterns were those accounted for by extralinguistic cues such as the relative proximity, mobility or position of the referents. The significance of early interpretation rules of this sort for any characterization of young children's language comprehension processes is discussed.

American health planning and the lessons of comparative policy analysis

This paper reviews case studies of eighteen countries to identify similarities and differences in health planning problems and institutional arrangements for resolving them. On the basis of this review, it is argued that in order for cost-containment to be effective in the United States, planning agencies need to have control over resource allocation.