Sam T. Donta

Clostridium difficile toxin in asymptomatic neonates

Clostridium difficile toxin was detected in the feces of 10.5% of normal newborn infants and 55% of neonates in the intensive care unit. None of the normal infants and less than one-third of those in the NICU had any signs of enteric illness. Vaginal delivery and breast-feeding were associated with increased rates of toxin carriage. Although toxin was not detected during antibiotic therapy, it could be found in 85% of infants two weeks or more, and for at least an additional two months, following exposure to antibiotics.

Classification of Enterotoxins on the Basis of Activity in Cell Culture

Two cell culture systems were used in a study of the biological properties of several bacterial enterotoxins in vitro. By means of one model, in which HeLa cell monolayers were used, cytotoxic effects, interms of detachment of cells from a glass surface due to cell death, were assayed. By means of the second model, activation of the adenyl cyclase-cyclic adenosine 3, 5-monophosphate (AMP) system, in terms of increased steroidogenesis by Y-1 adrenal cells (an effect which we have termed cytotonic), was assayed. None of the four toxins manifested both properties. Rather there was a clear segregation into two cytotoxic enterotoxins (Shigella dysenteriae type 1 and Clostridium perfingens) and two cytotonic products (Vibrio cholerae and Escherichia coli). These data raise the possibility that some enterotoxins may not interact with the adenyl cyclase-cyclic AMP system; this possibility has also been suggested by studies of the toxin of S. dysenteriae type 1 in the rabbit small bowel. These cell culture systems may therefore serve as convenient models for the study of the mechanism of action of both classes of enterotoxin.

Risk factors for upper gastrointestinal bleeding in intensive care unit patients: role of helicobacter pylori. Federal Hyperimmune Immunoglobulin Therapy Study Group

OBJECTIVEnTo determine the role of preexisting Helicobacter pylori infection in the development of acute upper gastrointestinal (GI) hemorrhage in intensive care unit (ICU) patients in relation to other potential predisposing risk factors.nnnDESIGNnProspective, multicenter, cohort study.nnnSETTINGnMedical and surgical ICUs in six tertiary care Department of Veterans Affairs Medical Centers.nnnPATIENTSnEight-hundred seventy-four patients without previous GI bleeding or peptic ulcer disease who were enrolled in a multicenter, randomized, controlled trial of prophylactic intravenous immunoglobulin to prevent ICU-associated infections.nnnINTERVENTIONSnThis substudy of the larger intravenous immunoglobulin study only involved data analysis and had no intervention. All patients were enrolled in the larger study where they received intravenous immunoglobulin or placebo as intervention.nnnMEASUREMENTS AND MAIN RESULTSnPatients were prospectively evaluated for the development of acute upper GI hemorrhage while in an ICU. Anti-H. pylori immunoglobulin G and immnoglobulin A concentrations were determined by enzyme immunoassay on preintervention serum samples. Seventy-six (9%) patients had over upper GI bleeding and a mortality rate of 49%, as compared with a 15% mortality rate in patients who did not bleed (p < .001). By logistic regression analysis, the following factors were associated with an increased risk of bleeding: acute hepatic failure, prolonged duration of nasogastric tube placement, alcoholism, and an increased serum concentration of anti-H. pylori immunoglobulin A.nnnCONCLUSIONSnIncreased anti-H. pylori immunoglobulin A concentrations, prolonged nasogastric intubation, alcoholism, and acute hepatic failure were found to be independently correlated with the development of acute GI bleeding in an ICU setting. These observations should be prospectively confirmed in an independent population before being used for treatment guidelines.

Benefits and harms of doxycycline treatment for Gulf War Veterans' illnesses: A randomized, double-blind, placebo-controlled trial

Context Some experts hypothesize that Mycoplasma species cause Gulf War veterans illnesses (GWVIs). Contribution In this double-blind trial, 491 deployed Gulf War veterans with GWVIs and detectable Mycoplasma DNA in their blood were randomly assigned to receive either doxycycline, 200 mg, or matching placebo daily for 1 year. There were no long-term differences between the 2 groups in physical or mental function or in pain or fatigue symptoms. Patients given doxycycline had nausea and photo-sensitivity more often than did patients given placebo. Implications Long-term doxycycline treatment probably doesnt benefit veterans with GWVIs and may harm them. The Editors An estimated 15% to 20% of the 700 000 troops who were deployed to the Persian Gulf in 1990 through 1991 have reported debilitating symptoms that as yet have no definitive explanation (1-6). The most common are fatigue, musculoskeletal pain, and neurocognitive problems. This complex of symptoms is clinically indistinguishable from that of the chronic fatigue syndrome and fibromyalgia, and the resulting disorders have been called Gulf War veterans illnesses (GWVIs). Several explanations for GWVIs have been proposed, including exposure to bacterial pathogens or neurotoxic chemicals, allergic reactions, metabolic disorders, rheumatologic conditions, and psychological factors (7-11). However, the cause or causes of GWVIs have yet to be identified. It has been hypothesized that GWVIs are caused by an underlying systemic infection with Mycoplasma species, the most common being the bacterial pathogen M. fermentans, and that long-term treatment with doxycycline might be efficacious (7, 12-14). Preliminary observations were not strong, and controlled clinical trials to support this treatment approach were lacking. However, because of the need to provide relief to veterans with GWVIs, the U.S. Departments of Veterans Affairs and Defense conducted a randomized, placebo-controlled clinical trial to determine whether doxycycline treatment would improve physical function. Methods The background, methods, and rationale for the study design have been described in detail elsewhere (15) and are only briefly described here. Study Design and Participants We performed an 18-month, randomized, double-blind, placebo-controlled clinical trial. The primary objective was to determine whether a 12-month course of treatment with doxycycline improved functional status in deployed veterans with GWVIs whose blood tested positive for Mycoplasma DNA. Secondary objectives were to determine whether doxycycline treatment reduced the symptoms of GWVIs and whether results of DNA tests for Mycoplasma species converted from positive to negative after treatment. The study was conducted at 26 Department of Veterans Affairs and 2 Department of Defense medical centers between April 1999 and November 2001. Participants were recruited through mailings, advertisements, and physician referrals. Veterans were eligible for study enrollment if they had been deployed from active duty, the National Guard, or the military Reserve to the Southwest Asia theater of operations between August 1990 and August 1991 and developed at least 2 of 3 primary symptoms of GWVIs after deployment (fatigue, musculoskeletal pain involving 2 or more regions of the body, and cognitive problems). Symptoms had to have lasted more than 6 months and had to be present at the time of screening. Additional requirements were a score less than 40 on the Physical Component Summary of the Veterans Short Form-36 (SF-36) Health Survey, which was completed at screening, and a positive result on a polymerase chain reaction DNA test for M. fermentans, M. genitalium, or M. pneumoniae DNA in whole blood (sensitivity level, 1 to 10 Mycoplasma genomes). The study coordinator initially reviewed veterans for study eligibility, but physician-investigators at each site made the final determination regarding inclusion. Veterans were excluded for the following reasons: attribution of symptoms to another medical condition (morbid obesity; autoimmune diseases; uncontrolled cardiopulmonary and endocrine disorders; malignant conditions, except skin cancer, within 2 years; or known current liver disease); doxycycline allergy; previous treatment with doxycycline for more than 6 months since the onset of symptoms; continuous treatment with a tetracycline, macrolide, or quinolone antibiotic for more than 1 month during the past year; history of severe psychiatric illness (history of psychosis or hospitalization for mental illness in the past 2 years); active substance abuse requiring hospitalization or active treatment within 2 years of enrollment; organ transplantation; life expectancy of less than 1 year; required treatment with phenytoin, carbamazepine, or barbiturates; unwillingness to be randomly assigned to doxycycline or placebo; or, if female, unwillingness to use barrier-method contraceptives. Veterans who had received a diagnosis of the chronic fatigue syndrome or fibromyalgia were not excluded because these disorders are similar in character and definition to GWVIs. All participants provided written informed consent. Treatment Protocol The Department of Veterans Affairs Cooperative Studies Evaluation Committee, a central human rights committee, and each participating sites institutional review board approved the study protocol. An independent data and safety monitoring board reviewed the study semiannually. Participants assigned to the doxycycline group received doxycycline, 200 mg/d, and those assigned to the placebo group received identically matched lactose capsules. Because doxycycline can cause photosensitivity to sunlight, all participants were provided with sunscreen (sun protection factor, 30) and were advised to limit sun exposure. Participants were followed for an additional 6 months after withdrawal of study drugs to determine potential relapse rates. Because of the expense of Mycoplasma testing and an expected 3- to 4-week delay in receiving the test results, participants had to meet all other eligibility criteria before blood was drawn. To ensure that outcome measure testing was performed as close as possible to the start of treatment with the study drug, baseline testing, including repeated administration of the Veterans SF-36 Health Survey, was completed at randomization just before the study drug was dispensed to participants. Major assessments were completed at baseline and at 3, 6, 9, 12, and 18 months. Major assessments consisted of the Veterans SF-36 Health Survey (16-18), the McGill Pain Questionnaire (19), the Multidimensional Fatigue Inventory (20), and the Cognitive Failures Questionnaire (21). Monthly follow-up visits were conducted to dispense medication; to monitor adherence to treatment regimen by pill counts and discussions with participants; and to collect information on hospitalizations, clinic visits, other medications used, and adverse events. Participants who were not taking their medications routinely were encouraged to do so. Laboratory evaluations (blood chemistry tests and testing of doxycycline level) were performed on participant blood samples at the 6- and 12-month follow-up visits. Polymerase chain reaction detection of M. fermentans, M. genitalium, and M. pneumoniae DNA was determined in blood samples obtained at baseline and at 6, 12, and 18 months. Outcome Assessments The primary outcome measure was the Physical Component Summary score of the Veterans SF-36 Health Survey at follow-up compared with baseline. The Veterans SF-36 Health Survey is modified from the Medical Outcomes Study SF-36 Health Survey and is adapted for use in veterans with improved reliability and precision (16-18, 22-24). The Physical Component Summary is a weighted standardized summary measure, normalized to a mean score of 50 on the basis of a general U.S. population (18). Higher scores denote better functional status. The Physical Component Summary was selected as the primary outcome measure because there is no validated disease-specific assessment of functional status for GWVIs and because the Veterans SF-36 Health Survey spans a spectrum of functional status that is conceptually and clinically relevant to GWVIs. The primary end point was the dichotomous measure of the proportion of participants with more than a 7-unit increase in the Physical Component Summary score at 12 months. Treatment was considered to have failed in participants who did not have more than a 7-unit increase from their baseline Physical Component Summary score, those who did not complete the study, and those who had missing 12-month Physical Component Summary scores. The change of 7 units or greater was selected because it is outside the 95% CI for an individual participant score (standard error of the measurement), as estimated from the standard deviation and score reliability (25). Differences of this magnitude have also been shown to be clinically relevant (26-29). The secondary outcomes were reduction in symptoms, improvement in physical and mental health function as continuous measures of change, and conversion to Mycoplasma negativity (that is, negative results for Mycoplasma DNA by polymerase chain reaction testing of whole blood). A reduction in symptoms was determined by using 3 self-report questionnaires: the McGill Pain Questionnaire, the Multidimensional Fatigue Inventory, and the Cognitive Failures Questionnaire. Changes in physical and mental health function were measured by using continuous measures of change in the Physical Component Summary and Mental Component Summary scores of the Veterans SF-36 Health Survey. Table 1 summarizes the measures from each of these questionnaires. Table 1. Secondary Outcome Measures Laboratory Methods Polymerase chain reaction testing was performed at the University of Texas Health Science Center in San Antonio, Texas. Whole blood samples were drawn from participants at baseline and at 6, 12, and 18 months

Immunotherapy of sepsis: flawed concept or faulty implementation?

Gram-negative bacillary sepsis is a leading cause of death among patients hospitalized in intensive care units. While initial clinical studies with the passive administration of anti-endotoxin core-glycolipid (CGL) antibodies for the treatment and prophylaxis of sepsis showed promising results, subsequent studies failed to show a consistent benefit. There appears to be a good correlation between anti-CGL antibody levels at the onset of sepsis and maintenance of antibody levels during sepsis with outcome. Previous clinical studies may have failed because insufficient amounts of antibody were administered early in the course of sepsis. Unlike the case with anti-CGL antibodies, polyvalent, hyperimmune type-specific antibody preparations may prevent the development of infections; however, these antibodies also must be provided in adequate amounts and in close proximity to infection in order to provide a beneficial effect. These pharmacokinetic requirements may limit the utility of passive immunotherapy for the prophylaxis of sepsis. Active immunization of acutely traumatized patients or of rats subsequently rendered neutropenic with cyclophosphamide induced high antibody levels for extended periods of time. Since trauma and other conditions are associated with a Th(2) response, these conditions may favor antibody formation following active immunization. Active immunization with both anti-CGL and/or polyvalent-specific vaccines for the prophylaxis of sepsis with passive supplementation at the onset of sepsis is an approach that merits further investigation.

Predictors of Exercise Compliance in Individuals with Gulf War Veterans Illnesses: Department of Veterans Affairs Cooperative Study 470

Although the health benefits of exercise for individuals with Persian Gulf War veterans illnesses (GWVI) are documented, many of these individuals do not exercise regularly enough to obtain benefits. The purpose of this study was to investigate factors predicting exercise compliance among individuals with GWVI in a multicenter, randomized, clinical trial. Participants were 1,092 veterans who reported at least two of the following cardinal symptoms of GWVI: (1) fatigue, (2) musculoskeletal pain, and (3) cognitive problems. Participants received exercise alone or exercise and cognitive-behavioral therapy. The overall level of compliance was relatively low during the exercise treatment phase (46.2%) and decreased by one-half during the follow-up period (23.0%). Predictors of compliance during treatment included less pain and greater age, motivation, and body mass index. Predictors of compliance during the follow-up period included less pain and greater age. The results highlight factors that affect adoption and maintenance of physical activity in a population with GWVI.

A Multicenter Two by Two Factorial Trial of Cognitive Behavioral Therapy and Aerobic Exercise for Gulf War Veterans' Illnesses: Design of a Veterans Affairs Cooperative Study (CSP #470)

The Department of Veterans Affairs (VA) Cooperative Studies Program (CSP) Study #470 is a 2 x 2 factorial trial designed to evaluate the hypothesis that both cognitive behavioral therapy (CBT) and aerobic exercise will significantly improve physical function in participants with Gulf War veterans illnesses (GWVI), and that adding CBT to aerobic exercise will provide further incremental benefit. One thousand three hundred fifty-six veterans will be randomized to one of four treatment arms: CBT plus aerobic exercise plus usual and customary care, aerobic exercise plus usual and customary care, CBT plus usual and customary care, or usual and customary care alone. The study duration is 2.5 years with 1.5 years of intake and 1 year of follow-up. The primary outcome measure is the proportion of veterans improved more than seven units on the physical component summary (PCS) scale of the Short Form Health Survey for Veterans (SF-36V) measured 12 months after randomization. This generic quality-of-life measure was chosen because there is no disease-specific measure for GWVI and the symptoms of GWVI span a wide range of physical manifestations that are related to the domains covered by the PCS scale. Sample size was determined to detect all six pairwise comparisons between the four treatment arms with 90% power and a Bonferroni adjustment for an overall type I error of 0.05 or 0.05/6 = 0.0083. CSP #470 was initiated in May 1999 in 18 VA and two Department of Defense medical centers. To date this represents the largest randomized trial designed to evaluate treatments for individuals with unexplained physical symptoms. This paper will focus on the rationale and unique features of the study design. Control Clin Trials 2001;22:310-332

The Antibiotic Treatment Trial of Gulf War Veterans' Illnesses: issues, design, screening, and baseline characteristics

Many veterans who were deployed to the Persian Gulf during the 1990-1991 Gulf War developed multiple unexplained symptoms such as pain, fatigue, and neurocognitive problems. This constellation of symptoms has been termed Gulf War Veterans Illnesses (GWVI). Although there is no proven explanation for the cause of GWVI, one fairly widespread explanation is systemic Mycoplasma fermentans infection. The Antibiotic Treatment Trial of GWVI is a randomized placebo-controlled trial to determine whether a 1-year course of doxycycline treatment in deployed Gulf War veterans with GWVI and testing as Mycoplasma species positive will improve their overall functional status as measured by the Physical Component Summary of the SF-36V questionnaire. The study of a multisymptom illness such as GWVI is complicated by the nonspecific nature of the illness, the unknown etiology, and the lack of a widely accepted outcome measure. The presumption of mycoplasma infection raises concerns regarding the methodology for determination of mycoplasma infection, the choice of treatment, and the duration of treatment. However, such a presumption allows the formulation of a clear testable hypothesis that can be tested with treatments with known rates of adverse events and known activity against Mycoplasma species. This paper describes the major issues faced by the investigators during planning, the study design, the patient screening results, and the baseline characteristics of the study patients. There were 2712 patients screened for study entry at 26 Department of Veterans Affairs and two Department of Defense medical centers. Of these, 491 met all study entry criteria and were randomized to either 1 year of doxycycline (200 mg/day) or 1 year of placebo. All patients were seen monthly during treatment and at 6 months after the end of treatment. Study patients had a mean age of 41 years and were mostly male (86%), white (64%), married (68%), and employed full-time (71%).

Research on informed consent: investigator-developed versus focus group-developed consent documents, a VA cooperative study.

In the Department of Veterans Affairs Cooperative Study (VACSP) #470, A Randomized, Multicenter, Controlled Trial of Multi-Modal Therapy in Veterans with Gulf War Illnesses, a substudy was designed with the primary objective of comparing the utility of an informed consent document developed by a focus group of Gulf War veterans (focus group-developed) to an informed consent document developed by the standard process involving the study investigators (investigator-developed). In December 1998 a focus group of five Gulf War veterans convened at the coordinating center and developed a consent document during three sessions. The focus group used the investigator-developed consent document as a starting point and then modified it by consensus agreement. They also reviewed and modified the substudys assessment questionnaire. Utility will be evaluated in 1092 veterans participating in the parent study, VACSP #470, by directly comparing selected patient-centered outcomes between those receiving the focus group-developed consent document versus those receiving the investigator-developed document. The primary outcomes to be evaluated over a 1-year follow-up period include measures of the informed consent process, such as patient recall, expectations about risks and benefits of participation, and understanding about the voluntariness of consent. Secondary outcomes will assess the impact of the substudy on the parent study with respect to recruitment and adherence. VACSP #470 was initiated in May 1999 in 20 sites that were randomly allocated to use either the focus group-developed or investigator-developed consent document. Sites are unaware of the type of consent document assigned. This article focuses on the rationale and design of the informed consent substudy and also discusses potential ethical issues.

Specificity of attachment of certain enterobacteriaceae to mammalian cells.

The specificity of adherence of various Enterobacteriaceae to different mammalian cells was studied in vitro. 3H-Labelled organisms of the same species isolated from various clinical sources differed significantly in their abilities to adhere to the same mammalian cells. Bacteria frequently adhered better to cells derived from sites other than those analogous to their original source. Bacteria did not display consistently high or low attachment to a variety of human and tissue-cultured cells and little selective adherence was demonstrable.