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PubMed1993

Antibodies to Mycobacterium paratuberculosis and nine species of environmental mycobacteria in Crohn's disease and control subjects.

Cultural and serological studies have provided limited, often conflicting, evidence of a role for mycobacteria in the pathogenesis of Crohn's disease. Interest has focussed on Mycobacterium paratuberculosis, previously considered to be common in the environment with no major role as a human pathogen. Whether a specific serum antibody response to mycobacteria occurs in Crohn's disease or ulcerative colitis was investigated. Sera from patients with Crohn's disease (n = 38), ulcerative colitis (n = 15), and a healthy control population (n = 30) were assayed in an enzyme linked immunosorbent assay (ELISA) using eight filtered sonicate mycobacterial preparations and a purified protein derivative made from the bovine tubercle bacillus. In addition, IgG, IgM, and IgA levels to M paratuberculosis were determined in sera from patients with active (n = 24) or inactive (n = 29) Crohn's disease and the control populations. There was strong evidence of contact with environmental mycobacteria in all patients and control populations, with the greatest responses to preparations of M avium, M tuberculosis, and M kansasii. A large proportion of patients with Crohn's disease had antibodies that bound most antigens tested but there were no statistical differences between these values and those of the control population. Similarly, there were no differences in antibody levels to M paratuberculosis in patient and control groups. Although a subset of patients with active Crohn's disease (25%) had IgG concentrations that exceeded the control mean by more than 2 SD, this phenomenon may not be specific to Crohn's disease: 20% of a small group of patients with coeliac disease had similarly raised IgG levels to M paratuberculosis. These findings do not provide serological evidence of a role for this organism in the pathogenesis of Crohn's disease.

Antibodies, Bacterial↗
PubMed1999

Stem cell function and engraftment is not affected by "in vivo purging" with rituximab for autologous stem cell treatment for patients with low-grade non-Hodgkin's lymphoma.

The chimeric anti-CD20 monoclonal antibody rituximab (Rituxan; IDEC Pharmaceuticals, San Diego, CA, and Genentech, Inc, San Francisco, CA) has recently been approved by the US Food and Drug Administration as single-agent treatment of relapsed/refractory low-grade or follicular non-Hodgkin's lymphoma. Initial results from the pivotal clinical trial revealed that response rates to rituximab were higher in patients who previously had high-dose therapy and autologous stem cell transplantation. We have initiated a clinical trial that combines the use of rituximab with high-dose chemotherapy followed by autologous stem cell transplantation for patients with chemosensitive relapsed follicular small cleaved or mantle cell lymphoma. A unique feature of this study is that in addition to eight maintenance infusions of rituximab after autologous stem cell transplantation, patients also received rituximab 375 mg/m2 2 days before a granulocyte colony-stimulating factor-mobilized stem cell collection as "in vivo purge." We report on preliminary results demonstrating the safety and efficacy of the in vivo purge on 10 patients undergoing stem cell mobilization, nine of whom have already undergone transplantation. The peripheral blood CD34+ counts were 14.92 and 20 x 10(6)/L on day 4 and day 5, respectively, of the stem cell mobilization with granulocyte colony-stimulating factor. This compares with 11.7 and 11.8 x 10(6)/L, respectively, for the control population. The median CD34 stem cell yield in the graft collection was 3.7 x 10(6)/kg in patients receiving rituximab in vivo purge compared with 3.1 x 10(6)/kg in the control population. The target stem cell collection was successfully collected in six of 10 patients in a 1-day single large-volume leukapheresis collection, while two patients required 2 days and the last two patients required 3 days. Functional assays revealed the stem cell colony-forming unit-granulocyte monocyte and burst-forming unit-erythrocyte to be 55 and 44 colonies per plate, respectively, for the patients receiving the in vivo rituximab purge. This compares favorably with 37 and 38.5 colonies per plate, respectively, for the control population. Neutrophil engraftment took a median of 11 days for both cohorts; platelet independence was achieved in 8 days compared with 10 days for the control population. The median number of platelet transfusions was two for patients receiving rituximab and 2.5 for the control group. Assessment of serum cytokines immediately before the rituximab infusion during the stem cell mobilization and immediately after revealed a twofold to sevenfold increase in interleukin-1beta, tumor necrosis factor-alpha, and interleukin-6. The polymerase chain reaction analysis for minimal residual disease in stem cell collections and in peripheral blood and bone marrow samples of these patients will help to determine the efficacy of rituximab in vivo purge on disease progression.

Adult↗
PubMed2002

Isolated gastrocnemius tightness.

BACKGROUND: Contracture of the gastrocnemius-soleus complex has well-documented deleterious effects on lower-limb function in spastic or neurologically impaired individuals. There is scarce literature, however, on the existence of isolated gastrocnemius contracture or its impact in otherwise normal patients. We hypothesized that an inability to dorsiflex the ankle due to equinus contracture leads to increased pain in the forefoot and/or midfoot and therefore a population with such pain will have less maximum ankle dorsiflexion than controls. We further postulated that the difference would be present whether the knee was extended or flexed. METHODS: This investigation was a prospective comparison of maximal ankle dorsiflexion, as a proxy for gastrocnemius tension, in response to a load applied to the undersurface of the foot in two healthy age, weight, and sex-matched groups. The patient group comprised thirty-four consecutive patients with a diagnosis of metatarsalgia or related midfoot and/or forefoot symptoms. The control group consisted of thirty-four individuals without foot or ankle symptoms. The participants were clinically examined for gastrocnemius and soleus contracture and were subsequently assessed for tightness with use of a specially designed electrogoniometer. Measurements were made both with the knee extended (the gastrocnemius under tension) and with the knee flexed (the gastrocnemius relaxed). RESULTS: With the knee fully extended, the average maximal ankle dorsiflexion was 4.5 degrees in the patient group and 13.1 degrees in the control group (p < 0.001). With the knee flexed 90 degrees, the average was 17.9 degrees in the patient group and 22.3 degrees in the control population (p = 0.09). When gastrocnemius contracture was defined as dorsiflexion of < or = 5 degrees during knee extension, it was identified in 65% of the patients compared with 24% of the control population. However, when gastrocnemius contracture was defined as dorsiflexion of < or = 10 degrees, it was present in 88% and 44%, respectively. When gastrocnemius-soleus contracture was defined as dorsiflexion of < or = 10 degrees with the knee in 90 degrees of flexion, it was identified in 29% of the patient group and 15% of the control group. CONCLUSIONS: On the average, patients with forefoot and/or midfoot symptoms had less maximum ankle dorsiflexion with the knee extended than did a control population without foot or ankle symptoms. When the knee was flexed 90 degrees to relax the gastrocnemius, this difference was no longer present. CLINICAL RELEVANCE: These findings support the existence of isolated gastrocnemius contracture in the development of forefoot and/or midfoot pathology in otherwise healthy people. These data may have implications for preventative and therapeutic care of patients with chronic foot problems.

Adult↗
PubMed1994

Is living near a coking works harmful to health? A study of industrial air pollution.

OBJECTIVE: To determine whether there was excess ill health in people living near a coking works, and if so whether it was related to exposure to coking works' emissions. DESIGN: Populations varying in proximity to the coking works were compared with control populations. Health data were correlated with available environmental data. METHODS: Analysis of routinely collected mortality, cancer registration, and birth statistics; community survey using self completed postal questionnaires; retrospective analysis of general practice (GP) records; tests of respiratory function; and analysis of available environmental data. MAIN RESULTS: Study and control populations were comparable in terms of response rates, gender, and most socioeconomic indicators. For adults, age standardised mortality and cancer rates of the population closest to the coking works were comparable with those for the district as a whole. Gender ratios, birthweight, and stillbirth rates were comparable in the study and control populations. For several indicators of respiratory health including cough, sinus trouble, glue ear, and wheeze (but not for asthma and chronic bronchitis) there was a gradient of self reported ill health, with the highest prevalence in areas closest to the works. For example, sinus trouble was reported by 20% of adults and 13% of children in the area closest to the works compared with 13% and 6% respectively in the control area. GP consultations for respiratory disorders increased when pollution (measured by SO2 levels) was high: annual consultation rates per 1000 varied from 752 in the top group of daily pollution levels to 424 in the bottom group. Analysis of locally collected smoke and SO2 data indicated that SO2 concentrations were highest closest to the works and, after closure of the coking works, the number of days on which SO2 and smoke levels exceeded 100 micrograms/m3 and 90 micrograms/m3, respectively, fell steeply. CONCLUSION: Routinely available indicators failed to provide convincing evidence that the coking works had harmed health. Self report and GP consultations indicated that respiratory ill health in the people living close to the works was worse than expected. Some of the excess probably resulted from exposure to coking works emissions. The health effects of relatively low level but intermittently high air pollution from a point source may be subtle, contributing to respiratory morbidity, but not apparent in analysis of routine health indicators.

Adolescent↗
PubMed2000

Risk of acquiring Creutzfeldt-Jakob disease from blood transfusions: systematic review of case-control studies.

OBJECTIVE: To determine the strength of association between history of blood transfusion and development of Creutzfeldt-Jakob disease. DATA SOURCES: English and non-English language articles published from January 1966 to January 1999 were retrieved using a keyword search of Medline and Embase. These were supplemented by handsearching key journals and searching bibliographies of reviews. STUDY SELECTION: Two independent reviewers selected the relevant abstracts and articles. Articles were chosen that reported the results of case-control studies trying to identify rates of prior blood transfusion in patients with Creutzfeldt-Jakob disease and in controls. DATA EXTRACTION: Odds ratios and information on study quality were extracted from the selected articles by two independent reviewers. DATA SYNTHESIS: Five studies containing data on 2479 patients were included. Three of the five studies used medical or neurological patients as controls, the other two used population controls. Odds ratios for developing Creutzfeldt-Jakob disease from blood transfusion ranged from 0.54 to 0.89. Four of the five studies had confidence intervals that crossed 1.0. The combined odds ratio was 0.70 (95% confidence interval 0.54 to 0.89). CONCLUSIONS: Case-control studies do not suggest a risk of developing Creutzfeldt-Jakob disease from blood transfusion. Rather, a trend seems to exist towards a lower frequency of previous blood transfusion in patients with Creutzfeldt-Jakob disease than in controls. However, it is important to be aware of these studies' methodological limitations-primarily the choice of control population and reliability of recall of transfusion status.

Case-Control Studies↗
PubMed1999

Dose-dependent effect of folic acid on the prevention of orofacial clefts.

OBJECTIVE: In 1982, Tolarova(4) found a reduction in the recurrence rate of isolated cleft lip (CL) with or without cleft palate (CP; CL +/- CP) after periconceptional supplementation with a multivitamin including a very high dose (10 mg) of folic acid. The Hungarian randomized, double-blind, controlled trial of periconceptional supplementation with a multivitamin including a physiologic dose (.8 mg) of folic acid did not show any preventive effect on the first occurrence of isolated CL +/- CP and CP. However, the general evaluation of congenital abnormalities in the Hungarian Case-Control Surveillance of Congenital Abnormalities indicated, among others, a reduction of isolated CL +/- CP and CP after the use of high doses of folic acid in the critical period for the development of these congenital abnormalities in the 12-year dataset between 1980 and 1991. We hypothesized that the prevention of orofacial clefts by folic acid has a dose-dependent effect, and this hypothesis was tested in 2 recent Hungarian datasets. DESIGN: In a prospective cohort study, the occurrence of isolated CL +/- CP and CP was studied in the newborn infants born to mothers with or without periconceptional folic acid-containing (.8 mg) multivitamin supplementation. Supplemented women with confirmed pregnancy were recruited from the participants of the periconceptional service. Unsupplemented women were invited to take part in the study after the first visit between the 8th and 12th week of gestation in the antenatal care. Supplemented and unsupplemented women were matched based on age, socioeconomic status, and residence. In contrast, the occurrence of high-dose (in general daily 6 mg) folic acid supplementation was evaluated in the case-control pairs of CL +/- CP and CP, particularly during the critical period of these 2 types of orofacial clefts in the 17 years dataset of the Case-Control Surveillance of Congenital Abnormalities, between 1980 and 1996. Cases were selected from the population-based Hungarian Congenital Abnormality Registry, whereas population controls without congenital abnormality were ascertained from the national birth registry. Two population controls were matched to every case according to sex, week of birth, and district of parental residence. The drug uses, including pregnancy supplements as folic acid, were evaluated based on retrospective self-reported maternal questionnaire and prospective medically documented data of antenatal care logbook. RESULTS: In the prospective cohort study, of 3019 informative offspring (termination of pregnancies in the second and third trimesters because of fetal defect, stillborn fetuses, and liveborn infants) in the supplemented group, 3 had CL +/- CP and 1 was affected with CP, whereas of 3432 informative offspring in the unsupplemented group, 2 had CL +/- CP and 1 had CP. The lack of preventive effect was in agreement with the result of the previous Hungarian randomized double-blind controlled trial; thus, these 2 datasets were combined. The preventive effect of a folic acid containing multivitamin used in the periconceptional period for the first occurrence of isolated CL +/- CP and CP was estimated by the Mantel-Haenszel test. Of 5488 supplemented women, 6 had CL +/- CP, and of 5821 unsupplemented women, 4 had CL +/- CP. Of 5489 supplemented women, 1 had CP, and of 5823 unsupplemented pregnant women, 3 had CP. The Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996, included 38 151 population controls (1.8% of the Hungarian births) and 22 865 cases with congenital abnormalities. Within the latter group, 1368 had isolated CL +/- CP, and 596 had CP. A significantly more frequent use of high-dose folic acid (in general daily 6 mg) supplementation was found in controls than in cases of 1246 case-control pairs of CL +/- CP group and of 537 case-control pairs of CP group, respectively. (ABSTRACT TRUNCATED)

Adult↗
PubMed1997

Squamous cell head and neck cancer in nonsmokers.

Tobacco and alcohol abuse are the major known risk factors for the development of squamous cell head and neck cancer (SCHNC). Information about this disease in nonsmokers, however, is limited. We retrospectively studied a group of 59 tobacco nonusers with SCHNC, diagnosed since 1986 at the Cleveland Clinic Foundation (CCF). Two objectives were defined: (a) to characterize this nonsmoking population of patients and identify any significant differences compared with a control population consisting of all patients diagnosed with SCHNC at the CCF between 1986 and 1993 and (b) to determine the prevalence of exposure to environmental tobacco smoke in this nonsmoking group of patients with SCHNC and compare it with the environmental tobacco-smoke exposure in a second, control population of non-SCHNC, nonsmoking patients matched for age, race, sex, and alcohol use. The group of nonsmoking patients with SCHNC was notable for only rare alcohol abuse, a preponderance of whites, and relatively fewer laryngeal primary tumors. There were significantly more women and more tongue primaries. When compared with the control population without cancer, the nonsmoking patients had a significantly higher risk of exposure to environmental tobacco smoke both in the home and in the workplace. We conclude that the tobacco nonuser who develops SCHNC is likely to be female and white and to have a primary tongue cancer. A significant association with environmental tobacco smoke exposure is suggested by our data.

Age Factors↗
PubMed2004

A diminished postnatal surge of Ad spermatogonia in cryptorchid infants is additional evidence for hypogonadotropic hypogonadism.

BACKGROUND: The aim of this study was to describe the development of Ad spermatogonia in both unilateral and bilateral cryptorchid infants compared to a control population of comparable age and to note particularly the fate of Ad spermatogonia during the normal surge of testosterone and gonadotropin. METHODS: The incidence and development of Ad (dark) adult type of spermatogonia were assessed in 270 testicular biopsies from 159 cryptorchid infants at 1-12 months of age. These results were compared to the control population of the same age. RESULTS: The number of Ad spermatogonia increased markedly after five months of life in the control population. The scrotal testes of unilateral cryptorchid infants also had an increase in the number of Ad spermatogonia but it was distinctly lower than that of the control population. In contrast, this surge was completely absent in the cryptorchid testes. The number of Ad spermatogonia in unilateral cryptorchid testes correlated in a nonlinear fashion with those in the contralateral scrotal testes. The total number of germ cells in the cryptorchid testes in the first six months of life is normal, after which time it declines rapidly. CONCLUSION: The impaired transformation of germ cells into Ad spermatogonia in both unilateral and bilateral cryptorchid infant testes during mini-puberty underscores the importance of hypogonadotropic-hypogonadism in the pathogenesis of this disease.

Biopsy, Needle↗
PubMed1999

Prevalence and phenotype consequence of FRAXA and FRAXE alleles in a large, ethnically diverse, special education-needs population.

We conducted a large population-based survey of fragile X (FRAXA) syndrome in ethnically diverse metropolitan Atlanta. The eligible study population consisted of public school children, aged 7-10 years, in special education-needs (SEN) classes. The purpose of the study was to estimate the prevalence among whites and, for the first time, African Americans, among a non-clinically referred population. At present, 5 males with FRAXA syndrome (4 whites and 1 African American), among 1,979 tested males, and no females, among 872 tested females, were identified. All males with FRAXA syndrome were mentally retarded and had been diagnosed previously. The prevalence for FRAXA syndrome was estimated to be 1/3,460 (confidence interval [CI] 1/7,143-1/1,742) for the general white male population and 1/4, 048 (CI 1/16,260-1/1,244) for the general African American male population. We also compared the frequency of intermediate and premutation FRAXA alleles (41-199 repeats) and fragile XE syndrome alleles (31-199 repeats) in the SEN population with that in a control population, to determine if there was a possible phenotype consequence of such high-repeat alleles, as has been reported previously. No difference was observed between our case and control populations, and no difference was observed between populations when the probands were grouped by a rough estimate of IQ based on class placement. These results suggest that there is no phenotype consequence of larger alleles that would cause carriers to be placed in an SEN class.

Alleles↗
PubMed2003

Leukocytes and bacteria in men with chronic prostatitis/chronic pelvic pain syndrome compared to asymptomatic controls.

PURPOSE: Chronic prostatitis has been traditionally characterized by inflammation and/or infection of the prostate gland, objectively categorized by white blood cells and cultured bacteria in prostate specific specimens. We compared leukocyte counts and localization rates for bacterial cultures of segmented urine samples (VB1, VB2, VB3), expressed prostatic secretion (EPS) and semen in men diagnosed with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) to men without pelvic pain (controls). MATERIALS AND METHODS: A total of 463 men enrolled in the National Institutes of Health Chronic Prostatitis Cohort study and 121 age matched men without urinary symptoms had leukocyte counts performed and 5-day bacterial cultures on specimens obtained from a standard 4-glass test (VB1, VB2, EPS, VB3) and semen. All risk factor comparisons between case and control analyses were tested using generalized Mantel-Haenszel methods, and multivariable models were developed using logistic regression methods, adjusting for clustering by clinical center within both methods. RESULTS: Men with CP/CPPS had statistically higher leukocyte counts in all segmented urine samples and EPS, but not in semen compared to asymptomatic control men. However, the control population also had a high prevalence of leukocytes. Of the men with CP/CPPS 50% and 32% had 5 or more, or 10 or more white blood cells (WBCs) per high power field, respectively, in EPS compared to 40% and 20% of the control population. Similarly, 32% and 14% of the patients with CP/CPPS had 5 or more, or 10 or more WBCs per high power field in VB3 compared to 19% and 11% in the control population. Localization of uropathogenic bacteria in EPS, VB3 and/or semen was similar in men with CP/CPPS (8.0%) and asymptomatic men (8.3%). CONCLUSIONS: Men with CP/CPPS have significantly higher leukocyte counts in all segmented urine samples and EPS but not in semen as compared to controls. There is no difference in rates of localization of bacterial cultures for men with CP/CPPS compared to control men. The high prevalence of WBCs and positive bacterial cultures in the asymptomatic control population raises questions about the clinical usefulness of the standard 4-glass test as a diagnostic tool in men with CP/CPPS.

Adult↗
PubMed1989

Effects of the positive inotropic agents milrinone and pimobendan on the development of lethal ischemic arrhythmias in conscious dogs with recent myocardial infarction.

The effects of milrinone and pimobendan upon the initiation of programmed ventricular stimulation-induced ventricular tachycardia (VT) and the incidence of lethal ischemic ventricular arrhythmias were assessed in conscious dogs with recent anterior myocardial infarctions. Based upon the results of previous studies, the animals which were entered into this investigation were nonresponsive to baseline programmed stimulation and, therefore, considered to be at "low risk" toward the development of subsequent lethal ischemic arrhythmias. Milrinone (200 micrograms/kg/h continuous i.v. infusion) and pimobendan (300 micrograms/kg i.v.) were administered in dosing regimens shown to produce equivalent and sustained increases in left ventricular (LV) + dP/dt. At the time of repeat electrophysiologic testing, 9 of 9 pimobendan-, 9 of 10 milrinone-, and 12 of 12 concurrent vehicle-treated animals remained nonresponsive to programmed ventricular stimulation. Compared to a total control population of 39 "low risk" postinfarction dogs; however, both milrinone and pimobendan administration increased the incidence of sudden ventricular fibrillation occurring in response to the development of acute posterolateral ischemia (milrinone 4 of 10 [40%] and pimobendan 4 of 10 [40%] versus "low risk" control population 4 of 39 [10.3%]; p = 0.038). The incidence of ischemic mortality at 24 h after the development of posterolateral myocardial ischemia was increased in the milrinone-treated group (6 of 10 [60%]) compared to the "low risk" control population (6 of 39 [15.2%]; p = 0.007), whereas the incidence of 24-h ischemic mortality in the pimobendan-treated group (4 of 10 [40%]) was only of borderline statistical significance when compared to that of the "low risk" control population (p = 0.083). Milrinone, but not pimobendan, delayed the onset of acute posterolateral myocardial ischemia in the postinfarction dogs. The predominant electrophysiologic effects of both milrinone and pimobendan were decreases in ventricular refractoriness in both non-infarct (NZ) and in infarct zones (IZ), as well as reductions in electrocardiographic QTc or QT intervals. These findings suggest that with both positive inotropic agents, including milrinone which may possess protective antithrombotic action, sudden death may be increased via a reduction in ventricular refractoriness in the ischemically injured heart. The enhanced susceptibility toward the development of ischemic ventricular arrhythmias in the presence of the inotropic interventions is not predicted by programmed ventricular stimulation testing prior to the ischemic event.

Animals↗
PubMed1997

Long-term survival after elective repair of infrarenal abdominal aortic aneurysm: results of a prospective multicentric study. Association for Academic Research in Vascular Surgery (AURC).

During 1989, 28 centers of the Association for Academic Research in Vascular Surgery (AURC) reported all cases involving patients with infrarenal abdominal aortic aneurysm (AAA) who reached the operating room alive. In a total series of 1107 procedures, 834 were performed electively. During 1993 and 1994, an effort was made to contact and, if possible re-examine the 794 (95.2%) patients who survived these elective procedures in order to establish survival curves, determine the causes of late death, and ascertain the predictive value for long-term survival of 628 perioperative variables recorded in 1989. Survival curves were calculated using the actuarial and Kaplan-Meier methods and compared with those obtained from national statistical records in a control population matched for age and sex. Variables with potential predictive value for late death were selected by univariate statistical analysis using either the chi2 or student t-test. In the group of 794 (92.5%) patients who survived elective AAA repair in 1989, survival rates were 93.9 +/- 1.8% at 1 year, 89.5 +/- 3.2% at 2 years, 83.5 +/- 3.2% at 3 years, 77.6 +/- 3.9% at 4 years, and 66.9 +/- 10.6% at 5 years. These rates were significantly lower than those observed in the control population. The mean annual death rate from cardiovascular disease was 1.8%, which was higher than in the control population matched for age and sex. Analysis using the Cox proportional risk model showed that the following variables were significant, independent predictors of late death: diameter of aneurysm (p < 0.02), choice of surgical approach in function of general status (p < 0.02), left ventricular insufficiency (p < 0.02), age (p < 0.02), carotid artery occlusion (p < 0.03), use of a surgical approach other than lobotomy (p < 0.04), cardiac arrhythmia (p < 0.04), duration of aortic clamping (p < 0.05), ECG evidence of myocardial ischemia (p < 0.05), abnormality at the upper limit of the aneurysm (p < 0.05), and advanced renal insufficiency (p < 0.05). Life expectancy in patients that undergo successful AAA repair is lower than in the general population. Although death is often unrelated to AAA or the repair procedure, the incidence of morbidity due to cardiovascular disease is higher than in a control population matched for age and sex. These findings suggest that better management of concurrent cardiovascular disease during the perioperative period and long-term follow-up holds the key to improving life expectancy in patients undergoing AAA repair.

Adult↗
PubMed2004

Decreased binding of annexin v to endothelial cells: a potential mechanism in atherothrombosis of patients with systemic lupus erythematosus.

OBJECTIVE: The cause of the exceedingly high risk of atherothrombosis in systemic lupus erythematosus (SLE) is not clear but antiphospholipid antibodies (aPL) and potentially antithrombotic annexin V have been implicated. METHODS AND RESULTS: Twenty-six women (52+/-8.2 years) with SLE and a history of cardiovascular disease (CVD) (SLE cases) were compared with 26 women with SLE but no CVD (SLE controls) and 26 healthy women (population controls). Common carotid intima-media thickness (IMT) was determined by B-mode ultrasound as a surrogate measure of atherosclerosis. Annexin V binding to human umbilical vein endothelial cells (HUVECs) as determined by flow cytometry after 24-hour culture with plasma was decreased when plasma from SLE cases was used (SLE cases versus population controls: P=0.002; SLE cases versus SLE controls P=0.02). Antibodies against cardiolipin were among IgG antibodies causing decreased binding. There was a positive association between annexin V binding and IMT (R=0.73; P<0.001) among SLE cases. Immunohistochemical analysis revealed presence of annexin V in all human atherosclerotic plaques tested, especially at sites prone to rupture. CONCLUSIONS: Decreased annexin V binding to endothelium caused by antibodies may represent a novel mechanism of atherothrombosis. We hypothesize that even though annexin V may promote plaque growth at some disease stages, it may also stabilize plaque.

Annexin A5↗
PubMedDate not supplied

Effect of O6-alkylguanine-DNA alkyltransferase on the frequency and spectrum of mutations induced by N-methyl-N'-nitro-N-nitrosoguanidine in the HPRT gene of diploid human fibroblasts.

N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) reacts with 12 nucleophilic sites in DNA to induce a variety of lesions, but O6-methylguanine (O6-MeG) and O4-methylthymine are the most effective premutagenic lesions produced, mispairing with thymine and guanine, respectively. O6-MeG is repaired by O6-alkylguanine-DNA alkyltransferase (AGT), which removes the methyl group from the O6 position and transfers it to itself, rendering the transferase inactive. When diploid human fibroblasts were exposed to 25 microM, O6-benzylguanine (O6-BzG) in the medium for 3 h, their level of AGT activity was dramatically reduced, to a level of at most 1.6% of the control. Populations of cells pretreated with this level of O6-BzG for 2 h or not pretreated, were exposed to MNNG at a concentration of 2, 4 or 6 microM in the presence or absence of O6-BzG and assayed for survival of colony-forming ability and the frequency of 6-thioguanine-resistant cells (mutations induced in the HPRT gene). O6-BzG (25 microM) was also present in the appropriate half of the cells during the 24 h immediately following exposure to MNNG. This 27-h exposure to O6-BzG alone had no cytotoxic or mutagenic effect on the cells but significantly increased the cytotoxicity and mutagenicity of MNNG, increasing the mutant frequency to that found previously in human cells constitutively devoid of AGT activity. At doses of 2 microM and 4 microM MNNG, the mutant frequency observed with the AGT-depleted cells was 120 x 10(-6) and 240 x 10(-6), respectively; in the cells with abundant AGT activity, these values were 10 x 10(-6) and 20 x 10(-6), respectively. DNA-sequence analysis of the coding region of the HPRT gene in 36 independent mutants obtained from MNNG-treated AGT-depleted populations and 36 from the control populations showed that even though AGT repair lowered the frequency of mutants by more than 90%, it did not affect the kinds of mutations induced by MNNG nor the strand distribution of the premutagenic guanine lesions. In mutants from the AGT-depleted cells, there were 26 base substitutions and 13 putative splice site mutations; in the control, there were 25 base substitutions and 11 splice site mutations. All but two substitutions involved G.C with 92% being G.C----A.T. In both sets, approximately 73% of the premutagenic lesions were located in the nontranscribed strand.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗