Natural cause mortality in persons with serious mental illness

OBJECTIVE

To identify the determinants of natural cause mortality in a cohort of individuals with serious mental illness assessed prospectively.

METHOD

Persons with schizophrenia (n = 789) and bipolar disorder (n = 498), mean age of 38 (s.d. 12.6) years, underwent an in-person clinical assessment. They also had a blood sample drawn from which infectious disease markers were measured. Mortality was subsequently determined utilizing data from the National Death Index following a period of up to 16.9 years.

RESULTS

A total of 6.8% (87 of 1287) of persons died of natural causes. Mortality was predicted in a multivariate model by baseline cigarette smoking (RR = 6.29, 95% CI 1.41, 3.72, P = 0.00076); divorced or widowed status (RR = 1.90, CI 1.21, 2.99); reduced cognitive score (RR = 0.73, CI 0.61, 0.87); receipt of antidepressant medication (RR = 1.74, CI 1.12, 2.71); elevated levels of antibodies to Epstein-Barr virus (EBV) (RR = 1.29, CI 1.01, 1.66); and a genitourinary (RR = 1.82, CI 1.16, 2.86), respiratory (RR = 1.82, CI 1.16, 2.86), or cardiac (RR = 2.09, CI 1.33, 3.29) condition. There was an additive effect of smoking and both a cardiac and a respiratory condition but not elevated EBV antibody levels.

CONCLUSION

Smoking is a modifiable behaviour which is associated with mortality in this population.

Obesity increases the risk of small intestinal bacterial overgrowth (SIBO)

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) has been associated with anatomical and motility-related abnormalities. Specifically, obesity has been postulated to alter small bowel motility, leading to SIBO.

AIMS

(i) Assess the prevalence of SIBO in obesity; (ii) determine the relationship of obesity and SIBO, using small bowel transit time (SBTT) and pH; (iii) profile the gut microbiome in obese and non-obese patients with SIBO.

METHODS

Thirty consecutive participants referred for SIBO underwent lactulose breath tests (LBTs) and wireless motility capsule (WMC) studies. Composition of the intestinal microbiome was assessed by analyzing samples from three different gastrointestinal sites via 16S rRNA gene-sequencing.

KEY RESULTS

SIBO was more frequent among obese patients vs non-obese patients (88.9% vs 42.9%, P < .05). Obesity did not correlate with small bowel transit time (SBTT), gastric pH, and small bowel pH. In patients with normal SBTT, obesity was associated with an 11-fold increase (P = .05) in the risk of SIBO. Whereas in those with prolonged SBTT, there was no correlation between obesity and SIBO. Obese vs non-obese patients exhibited significant differences in microbiome diversity in rectal samples. Obesity was associated with increased odds of developing SIBO (P = .04) in multivariate regression analyses.

CONCLUSIONS AND INFERENCES

While obesity was significantly associated with SIBO, our findings suggest that alterations in gut pH, SBTT, and decline in species richness do not account for the obesity-SIBO relationship.

Toxoplasma gondii-A Gastrointestinal Pathogen Associated with Human Brain Diseases

Serious psychiatric disorders such as schizophrenia, bipolar disorder, and major depression are important causes of mortality and morbidity worldwide. While these are primarily diseases involving altered brain functioning, numerous studies have documented increased rates of gastrointestinal inflammation and dysfunction in many individuals with these disorders. Toxoplasma gondii is an apicomplexan protozoan intracellular parasite with a widespread distribution in both developed and developing countries. Toxoplasma organisms enter the ecosystem through the shedding of oocysts by Toxoplasma-infected felines. In almost all cases of postnatal human infection, Toxoplasma enters its hosts through the intestinal tract either by the ingestion of oocysts or by the consumption of meat from food animals which themselves were infected by Toxoplasma oocysts. It had previously been thought that most cases of Toxoplasma infection in immune competent children and adults were inapparent and asymptomatic. However, recent studies cast doubt on this concept as exposure to Toxoplasma has been associated with a range of acute and chronic symptoms. Of particular note has been the finding of an increased rate of a range of neurological and psychiatric disorders associated with serological evidence of Toxoplasma exposure. A role of Toxoplasma infection in brain diseases is also supported by the consistent finding of altered cognition and behavior in animal models of infections. Much of the attention relating to the role of Toxoplasma infection in neuropsychiatric disorders has focused on the brain, where Toxoplasma tissue cysts can persist for extended periods of time. However, recent discoveries relating to the role of the gastrointestinal tract in cognition and behavior suggest that Toxoplasma may also increase susceptibility to human brain diseases through immune activation, particularly involving the gastrointestinal mucosa. The study of the pathways relating to the pathobiology and immunology of Toxoplasma infection may provide insights into the pathogenesis of a range of human neuropsychiatric disorders as well as into cognitive functioning in otherwise healthy individuals.

Immune alterations in acute bipolar depression

OBJECTIVE

Immunologic abnormalities have been found in bipolar disorder and acute mania. However, there have been fewer studies of patients with acute bipolar depression.

METHOD

Blood samples were obtained from individuals with acute bipolar depression, acute mania, and controls. These samples were evaluated for antibodies to human herpesviruses, gliadin, Toxoplasma gondii, and endogenous retroviruses as well as for C-reactive protein (CRP) and pentraxin-3 using immunoassay methods. Linear regression models were used to compare the levels of the markers controlling for demographic and clinical variables. A subset of the bipolar depressed group was evaluated at a 6-month follow-up.

RESULTS

The sample consisted of 82 individuals with acute bipolar depression, 147 with acute mania, and 280 controls. The levels of CRP and IgG antibodies to an endogenous retrovirus, Mason-Pfizer monkey virus (MPMV), were significantly elevated in the bipolar depressed group. Levels of pentraxin-3 were reduced in both psychiatric groups. An evaluation of 32 individuals 6 months after hospitalization for bipolar depression showed a significant decrease in the levels of MPMV antibodies, but not a change in the other markers.

CONCLUSION

Individuals with acute bipolar depression show immune alterations. Some of the alterations are similar to those found in acute mania.

Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta-analysis

OBJECTIVE

To perform a meta-analysis on studies reporting prevalence of Toxoplasma gondii (T. gondii) infection in any psychiatric disorder compared with healthy controls. Our secondary objective was to analyze factors possibly moderating heterogeneity.

METHOD

A systematic search was performed to identify studies into T. gondii infection for all major psychiatric disorders versus healthy controls. Methodological quality, publication bias, and possible moderators were assessed.

RESULTS

A total of 2866 citations were retrieved and 50 studies finally included. Significant odds ratios (ORs) with IgG antibodies were found in schizophrenia (OR 1.81, P < 0.00001), bipolar disorder (OR 1.52, P = 0.02), obsessive-compulsive disorder (OR 3.4, P < 0.001), and addiction (OR 1.91, P < 0.00001), but not for major depression (OR 1.21, P = 0.28). Exploration of the association between T. gondii and schizophrenia yielded a significant effect of seropositivity before onset and serointensity, but not IgM antibodies or gender. The amplitude of the OR was influenced by region and general seroprevalence. Moderators together accounted for 56% of the observed variance in study effects. After controlling for publication bias, the adjusted OR (1.43) in schizophrenia remained significant.

CONCLUSION

These findings suggest that T. gondii infection is associated with several psychiatric disorders and that in schizophrenia reactivation of latent T. gondii infection may occur.

Total synthesis of the cyanobacterial metabolite nostodione A: discovery of its antiparasitic activity against Toxoplasma gondii

A diversity-oriented total synthesis of nostodione-A and analogues and their antiparasitic activity againstToxoplasma gondiiis reported.

Molecular characteristics of Human Endogenous Retrovirus type-W in schizophrenia and bipolar disorder

Epidemiological and genome-wide association studies of severe psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BD), suggest complex interactions between multiple genetic elements and environmental factors. The involvement of genetic elements such as Human Endogenous Retroviruses type 'W' family (HERV-W) has consistently been associated with SZ. HERV-W envelope gene (env) is activated by environmental factors and encodes a protein displaying inflammation and neurotoxicity. The present study addressed the molecular characteristics of HERV-W env in SZ and BD. Hundred and thirty-six patients, 91 with BD, 45 with SZ and 73 healthy controls (HC) were included. HERV-W env transcription was found to be elevated in BD (P<10-4) and in SZ (P=0.012) as compared with HC, but with higher values in BD than in SZ group (P<0.01). The corresponding DNA copy number was paradoxically lower in the genome of patients with BD (P=0.0016) or SZ (P<0.0003) than in HC. Differences in nucleotide sequence of HERV-W env were found between patients with SZ and BD as compared with HC, as well as between SZ and BD. The molecular characteristics of HERV-W env also differ from what was observed in Multiple Sclerosis (MS) and may represent distinct features of the genome of patients with BD and SZ. The seroprevalence for Toxoplasma gondii yielded low but significant association with HERV-W transcriptional level in a subgroup of BD and SZ, suggesting a potential role in particular patients. A global hypothesis of mechanisms inducing such major psychoses is discussed, placing HERV-W at the crossroads between environmental, genetic and immunological factors. Thus, particular infections would act as activators of HERV-W elements in earliest life, resulting in the production of an HERV-W envelope protein, which then stimulates pro-inflammatory and neurotoxic cascades. This hypothesis needs to be further explored as it may yield major changes in our understanding and treatment of severe psychotic disorders.

Reduced expression of human endogenous retrovirus (HERV)-W GAG protein in the cingulate gyrus and hippocampus in schizophrenia, bipolar disorder, and depression

The human endogenous retrovirus (HERV)-W multicopy family was identified in human DNA from the previously characterized multiple sclerosis associated retroviral element (MSRV). Upregulation of the HERV-W POL has been reported in cerebrospinal fluid of patients with schizophrenia. The expression of capsid (GAG) protein of HERV-W was studied by immunohistochemistry and western blotting in postmortem brain tissue of the anterior cingulate cortex and hippocampal formation of normal controls and of patients with schizophrenia, bipolar disorder and major depression. A physiological expression of GAG protein was detected in neurons as well as astroglial cells in normal brain both in the anterior cingulate cortex and in the hippocampal formation. There was a statistically significant reduction of this expression in neurons and astroglial cells in brains from individuals with schizophrenia, major depression, and bipolar disorder. The results from the present study confirm that GAG protein encoded by the HERV-W multicopy gene family is expressed in cells of the central nervous system under normal conditions. Our findings of a cell type-, brain region- and disease-specific reduced expression in schizophrenia, major depression, and bipolar disorder are compatible with a pathophysiological role of HERVs in human brain disorders. The causes and biological consequences of this differential regulation will be the subject of further investigations.

Analysis of the DRPLA triplet repeat in brain tissue and leukocytes from schizophrenics

An expansion of the CAG triplet in the human gene called atrophin-1 or CTG-B37 causes the neuropsychiatric disease known as dentatorubral-pallidoluysian atrophy (DRPLA). We have examined the genomic DNA from brains and peripheral blood leukocytes (PBLs) of schizophrenic and non-schizophrenic individuals and PBLs from a cohort of monozygotic twins discordant or concordant for schizophrenia, for expansions of the CTG-B37 region. All samples, including non-schizophrenic/normal controls, had 7-22 CAG repeats in this region. Thus we found no evidence for an expansion of the DRPLA triplet repeat associated with schizophrenia when compared to controls. Our data suggest that an expansion in the CTG-B37 gene is not linked to or responsible for the disease schizophrenia.

Diarrhoeal diseases in the White Mountain Apaches: clinical studies

Acute diarrhoeal diseases continue to be a major health problem in certain underprivileged populations in the United States, including native Americans living in reservations. To describe the features of patients with diarrhoeal diseases requiring medical care, those attending the medical facilities of the Fort Apache Indian Reservation, Whiteriver, Arizona, were studied during 1981-1985. Clinical and aetiological information was obtained on 535 patients which constitute a 20% sample of those attending the outpatient clinic and all 386 patients who required 550 hospitalizations. Rotavirus, enterotoxigenic Escherichia coli, and Shigella were the most common aetiologic agents, a pattern similar to that seen in the developing countries. The clinical features of diarrhoeal illness and the frequent associated occurrence of acute respiratory symptoms, however, were remarkably similar, regardless of aetiology.

Diarrhoeal diseases in the White Mountain Apaches: epidemiologic studies

Acute diarrhoeal disease in children is known to be a major public health problem among native Americans living in reservations in the southwestern part of the United States. This study was undertaken to describe the epidemiology and causative agents of diarrhoea more completely, with the expectation that this information may help in the ultimate control of the disease in this population. Three interrelated epidemiologic studies were carried out in the White Mountain Apache Tribe, Whiteriver, Arizona, during 1981-1985: a three-year longitudinal study on a cohort of 112 newborns, a longitudinal two-year study in a cohort of 200 families, and a case-control study on 1,072 children with diarrhoea attending a medical facility. Both epidemiologic and microbiological patterns of diarrhoeal disease were found to be very similar to those seen in developing countries, indicating the need for basic improvements in sanitation and hygiene in this population.

Quantitative measurement of nonisotopically labeled polymerase chain reaction product

A novel approach for evaluation of polymerase chain reaction product was described. A biotin-labeled DNA (or RNA) probe is hybridized to the digoxigenin-labeled target PCR product. The hybrids are retained on an anti-biotin antibody-coated plate. An anti-digoxigenin Fab conjugated with alkaline phosphatase is used for generating either a fluorescence or a chromagenic substance. Both fluorogenic and chromagenic systems can be used for quantitative measurement of the PCR product/probe hybrids. The method is specific, fast, nonisotopic, sensitive, quantitative, and practical.

Prevalence of rotavirus on high-risk fomites in day-care facilities

STUDY OBJECTIVE

The objective of this study was to determine the prevalence of rotavirus contamination on environmental surfaces in day-care environments, using the polymerase chain reaction technique.

DESIGN

High-risk fomites were identified in two day-care centers and sampled biweekly during a 6-month study period. Water samples from water-play tables in each center were also collected during the study period. During an infectious disease outbreak, fomites were sampled from the rooms in which the outbreak occurred. Reverse transcriptase/polymerase chain reaction was carried out for viral detection of rotavirus from the fomites, and standard bacteriologic measures were used to detect bacteria in samples from water-play tables.

RESULTS

A total of 96 fomite samples were tested for presence of rotavirus from the two centers, of which 18/96 (19%) tested positive for rotavirus. The timing of the positive samples differed between the two centers. In the center that housed infants, a peak of rotavirus-positive fomites coincided with two enteric outbreaks. Rotavirus contamination was found on the telephone receiver, drinking fountain, water-play table, and toilet handles in both centers. Bacteria in large quantities were also identified in water-play table samples.

CONCLUSIONS

Moist surfaces including the telephone, water fountains, and water-play tables are common sources of rotavirus contamination within the day-care environment. Until a safe and affordable drug or vaccine against rotavirus is available for general use, avoidance of rotaviral infections is the most effective method for the prevention of rotavirus gastroenteritis.

Quantitative polymerase chain reaction by monitoring enzymatic activity of DNA polymerase

Nucleic acid amplification by polymerase chain reaction (PCR) is a very powerful technique in terms of sensitivity but is limited in terms of ability to perform accurate quantitation. While there is a theoretical correlation between copies of input target sequence and those of PCR product, the quantitative nature of this relationship is obscured by unpredictable variations in reaction conditions and by inhibitory and/or stimulatory substances which might be present in sample preparations, especially those derived from biological fluids. To reliably estimate copies of input DNA target from PCR product, we designed a combination of internal and external control systems coupled to DNA/RNA hybridization and enzymatic immunodetection techniques. The internal control system served to monitor amplification efficiency and to correct for the effects of inhibitors or stimuli on the efficiency of the DNA amplification. The assay is quantitative, nonisotopic, and can be widely applied to assessment of the quantity of DNA present in a wide range of preparations.

Detection of rotaviruses in the day care environment by reverse transcriptase polymerase chain reaction

Group A rotavirus is an important cause of morbidity among infants and toddlers in day care centers. Transmission by the fecal-oral route is well established, but fomites and environmental surfaces may also play an important role in transmission. A highly sensitive polymerase chain reaction (PCR) assay was used to detect rotavirus RNA in day care environments. Areas sampled included floors, diaper change areas, toy balls, and other surfaces. In two centers undergoing outbreaks of rotavirus, 7 (39%) of 18 toy balls had detectable rotavirus as did 8 (21%) of 39 swabs from environmental surfaces. By comparison, only 1 (5%) of 21 toy balls and 1 (2%) of 44 environmental surface swabs had detectable rotavirus in centers without rotavirus outbreaks (P = .0001). Thus, rotaviruses are highly prevalent in day care centers during outbreaks of diarrhea. The monitoring of environments by sensitive nucleic acid amplification techniques may lead to strategies for the diminution of disease transmission within the day care environment.

Use of modified nucleotides and uracil-DNA glycosylase (UNG) for the control of contamination in the PCR-based amplification of RNA

The inadvertent carryover of amplified fragments of nucleic acids (amplicons) is a potential source of contamination in the polymerase chain reaction. Recently, a method has been developed to generate amplicons with deoxyuracil triphosphate (dUTP) and to specifically hydrolyze these amplicons with uracil-DNA glycosylase (UNG) following the completion of the assay. We evaluated this system for the specific amplification of RNA from coxsackievirus A3 and B3. We found that RNA from both viruses could be amplified with dUTP, although the use of this triphosphate in place of TTP resulted in some loss of assay sensitivity. We also found that the dUTP-containing amplicons could be efficiently hydrolyzed by UNG, resulting in a 10,000,000-fold reduction in amplicon concentration with little effect on the native nucleic acid. The dUTP-UNG method has a great deal of potential for reducing amplicon contamination during the routine performance of nucleic acid amplification reactions.

Efficacy and pharmacokinetics of intravenous immune globulin administration to high-risk neonates

OBJECTIVE--To determine whether intravenous immune globulin (IVIG) administration modifies the incidence of infections in high-risk neonates. DESIGN--Randomized, double-blind study. SETTING--Neonatal intensive care unit at a tertiary care center.

PARTICIPANTS

A total of 170 infants were enrolled, 82 of whom received IVIG and 88 of whom received the placebo preparation. Infants were stratified by birth weight into one of three groups (category 1, those weighing less than 1000 g; category 2, those weighing between 1000 and 1500 g; and category 3, those weighing more than 1500 g). INTERVENTIONS--Intravenous immune globulin (750 mg/kg of body weight), or albumin placebo was administered within 72 hours of admission to the tertiary care center and every 14 days thereafter until discharge from the neonatal intensive care unit or age 3 months. Serum IgG levels were measured and data collected relating to the incidence of systemic and localized infections and to the course of hospitalization. MEASUREMENTS AND MAIN RESULTS--The administration of IVIG had no major side effects and resulted in higher serum IgG levels in infants in all birth weight categories compared with infants receiving the placebo. Systemic infections developed in five IVIG-treated infants and five placebo-treated infants. Administration of immunoglobulin had no significant effect on the rate of localized infections or necrotizing enterocolitis. It also did not affect hospital course of the infants as measured by length of hospitalization or the number of days on assisted ventilation, supplemental oxygen, or antibiotics was required. CONCLUSIONS--The general administration of IVIG using this dosage regimen has limited effects on the clinical course of infants in a neonatal intensive care unit.

Detection of animal and human group B rotaviruses in fecal specimens by polymerase chain reaction

A combined reverse transcriptase reaction-polymerase chain reaction (RT-PCR) was developed to achieve the sensitive detection of group B rotaviruses (GBR). Sequences derived from genomic segment 3 of the IDIR (intestinal disease of infant rats) strain of GBR permitted the detection of greater than or equal to 0.08 pg of purified IDIR genomic RNA (4,000 genome copies). Primers complementary to the terminal sequences of gene 11 of GBR strain ADRV (adult diarrhea rotavirus) allowed for the detection of as little as 0.008 pg of purified ADRV genomic RNA. Detection of heterologous strains of GBR was also observed with these primer pairs. IDIR gene 3 primers recognized greater than or equal to 8 pg of RNA from bovine GBR obtained from a variety of geographic locations. RNA from IDIR, but not bovine GBR, strains was detected by means of RT-PCR with ADRV gene 11 primers. Neither set of GBR primers was reactive in RT-PCR with fecal specimens containing group A rotaviruses or fecal specimens from uninfected controls. This RT-PCR assay permits the sensitive and specific detection of a variety of GBR in fecal specimens.

Improved detection of rotavirus shedding by polymerase chain reaction

To improve identification of children excreting rotavirus a method for the amplification of rotavirus RNA by the polymerase chain reaction (PCR) was developed. The assay was compared with a solid-phase enzyme immunoassay in the detection of rotavirus shedding by infants in hospital during the winter peak of rotavirus infections. Forty children were studied in an intermediate care unit after transfer from intensive care units. Only two were admitted primarily because of diarrhoea; the other thirty-eight were admitted for management of various other disorders. Rotavirus shedding was detected by enzyme immunoassay in twenty of the infants, and nine of these (aged 1 week to 8 months) remained in hospital for more than 5 days after the initial detection of rotavirus and could be studied long term. Of 103 faecal samples from the nine infants, 60 (58%) contained rotavirus RNA detected by reverse-transcriptase (RT)/PCR, whereas only 37 (36%) were positive for rotavirus antigen by the immunoassay (chi 2 = 10.3, p less than 0.002). The geometric mean time of rotavirus shedding was 9.5 (range 1-19) days as detected by RT/PCR and 5.7 (range 1-17) days by the immunoassay (p less than 0.018). In five of the nine children, RT/PCR detected rotavirus shedding for 2-7 days longer than the immunoassay and in four children RT/PCR was positive 1 or more days before rotavirus antigen was detected. Further studies should attempt to find out whether infected infants are capable of spreading wild-type virus during periods when they are not shedding antigen as detectable by enzyme immunoassay.

Occurrence of infectious symptoms in children in day care homes

Transmission of enteric pathogens is facilitated in child day care centers, including family day care homes, by frequent and intimate exposure among susceptible hosts, with diaper changing as the highest-risk procedure for such transmission. The objective of this study was to evaluate the effectiveness of an intervention program in decreasing the incidence of infectious disease symptoms in children attending family day care homes during a 12-month period. Each of 24 family day care homes was randomly assigned to an intervention or control group. The intervention included four components: (1) a handwashing educational program and (2) use of vinyl gloves, (3) use of disposable diaper changing pads, and (4) use of an alcohol-based hand rinse by the day care provider. Symptoms of enteric disease (diarrhea and vomiting) were significantly reduced in intervention family day care homes (p less than or equal to 0.05), whereas respiratory symptoms were not significantly different between intervention and control family day care homes (p = 0.35). Diarrhea was reported in 1 of every 100 child care days, representing one diarrhea episode per month in a typical family day care home.

Immunoglobulins and other modalities for the prevention and treatment of enteric viral infections

Viral infections of the gastrointestinal tract constitute a major health problem during the first years of life. In addition to causing acute diarrhea, rotaviruses and other enteric viruses may be involved in the pathogenesis of necrotizing enterocolitis and other neonatal enteric diseases. There are several potential methods for the prevention and treatment of gastrointestinal viral infections. Antiviral immune globulins, administered by the parenteral or oral route, might prove useful for the inhibition of intestinal viral replication. Alternatively, specific glycoprotein inhibitors of viral-cell binding might be used to prevent the productive infection of intestinal epithelial cells. In addition, since many enteric viruses require proteolytic enzymes for protein cleavage, protease inhibitors may prove to be effective agents for the inhibition of intestinal viral replication. At this point in time, these methods have proven useful for the inhibition of rotavirus infection in experimental animals. The successful application of these and other methods for the prevention of enteric infections in humans might substantially reduce the morbidity and mortality associated with enteric diseases.

Enzyme immunoassay for detection of hybrids between PCR-amplified HIV-1 DNA and a RNA probe: PCR-EIA

An enzyme immunoassay was developed to detect human immunodeficiency virus type 1 (HIV-1) DNA amplified by polymerase chain reaction (PCR-EIA). A set of primers (outer set) was used in PCR to amplify a segment of the HIV-1 gag gene from peripheral blood mononuclear cells. Hybrids between the amplified DNA and a RNA probe were measured in a microtiter plate immunoassay using a beta-D-galactosidase-conjugated monoclonal antibody to DNA-RNA hybrids and a fluorescent substrate. A second set of primers (nested set) located within the outer set was used in PCR with a known template to prepare the probe. One primer of the nested set included the T7 RNA polymerase promoter at its 5' end allowing transcription of a single-stranded RNA probe. Ten copies of HIV-1 DNA could be detected by PCR-EIA (42 fluorescent units with a background of 18 fluorescent units) compared with a detection limit of 1000 copies by ethidium bromide-stained agarose gel. HIV-1 DNA was detected by PCR-EIA in peripheral blood mononuclear cells from 32 of 33 seropositive patients (range 54-810 fluorescent units), and 0 of 25 seronegative patients (range 20-40 fluorescent units) (sensitivity 97%; specificity 100%). PCR-EIA offers a practical and nonisotopic method to objectively measure PCR-amplified HIV-1 DNA and has the potential for the measurement of other microbial pathogens in human body fluids.

Removal of inhibitory substances from human fecal specimens for detection of group A rotaviruses by reverse transcriptase and polymerase chain reactions

A method was developed for the purification of rotavirus RNA from fecal extracts in order to permit the sensitive identification of group A rotavirus in fecal specimens by the polymerase chain reaction. Sequential reactions with reverse transcriptase and Taq polymerase with directed primers from rotavirus gene 6 yielded characteristic 259-base-pair fragments that were then visualized by silver stain on a polyacrylamide gel. As few as 500 genomic copies of purified rotavirus RNA could be detected in this manner. However, when the method was applied to fecal samples with added rotavirus virions, inhibition was noted in many of the fecal extracts which were tested. The inhibition could be reversed by dilution of the fecal extract, but sensitivity was also reduced by a corresponding dilutional factor. The inhibition was quantitatively removed by an added step in the extraction process that utilized chromatographic cellulose fiber powder (CF11 powder) to purify the rotavirus RNA during a series of rapid washing and elution steps. After CF11 purification, rotavirus RNA could be detected in experimental fecal samples at dilutions 1,000- to 10,000-fold beyond the detection limits of standard techniques such as enzyme immunoassay and the direct visualization of RNA following polyacrylamide gel electrophoresis. Furthermore, following purification by CF11, rotavirus RNA could be detected in all of seven enzyme-linked immunosorbent assay-positive fecal samples obtained from a child with rotavirus gastroenteritis; when CF11 purification was not performed, rotavirus RNA could be detected in only four of these samples, even after the removal of inhibitors by dilution of the extracts. Large-scale identification of rotavirus in fecal specimens may be possible by use of CF11 purification of viral RNA prior to sequential reactions with reverse transcriptase and Taq polymerase in a modified polymerase chain reaction.

Infantile gastroenteritis associated with excretion of pestivirus antigens

Faeces from children under 2 years old who had gastroenteritis that could not be attributed to recognised enteric pathogens were examined with a monoclonal-antibody-based immunoassay for Pestivirus antigens. Such antigens were detected in 30 of 128 episodes of gastroenteritis. Children without diarrhoeal disease and children infected with rotaviruses had little evidence of Pestivirus infection (faeces positive in 1 of 28 and 1 of 31, respectively). The diarrhoeal disease in children excreting Pestivirus antigens resembled that in other children except that it was more commonly associated with signs and symptoms of respiratory inflammation.

Monoclonal antibody solution hybridization assay for detection of human immunodeficiency virus nucleic acids

In this report we describe a novel, nonisotopic hybridization assay for the measurement of viral RNA in biological samples. The assay involved a solution-phase reaction between a biotinylated DNA probe and RNA target sequences. Labeled hybrids were detected in an immunoreaction by using a solid-phase anti-biotin antibody and an enzyme-labeled monoclonal antibody specific for DNA-RNA hybrids. This monoclonal antibody solution hybridization assay was compared with an antigen-capture immunoassay for the detection of human immunodeficiency virus in 436 cell culture samples from 60 seropositive patients. The sensitivity and specificity of the hybridization assay were 93.5 and 94.6%, respectively. Detection of human immunodeficiency virus solely by hybridization in the initial sample but not subsequent samples from seven cultures may reflect detection of virus that was present in the patients' lymphocytes but did not replicate in vitro. Since the assay method is adapatable to the detection of either RNA or DNA, it could provide a means for the detection of a wide range of viral nucleic acids.

Identification of a group-reactive epitope of group B rotaviruses recognized by monoclonal antibody and application to the development of a sensitive immunoassay for viral characterization

Group B rotaviruses (GBRs) are fastidious agents which cause enteric disease in humans and a number of other animal species. Detailed study of the role of GBRs in human disease has been hampered by the lack of immunoreagents suitable for large-scale studies. We developed a monoclonal antibody which recognizes a group-reactive antigen contained in a number of strains of GBRs. When utilized in conjunction with a hyperimmune guinea pig antiserum to GBR, this monoclonal antibody can be used in an enzyme immunoassay system to detect a wide range of GBRs. Alternatively, this monoclonal antibody can be combined with sera obtained from GBR-infected animals to devise assays which are largely specific for the homologous strain of GBR. Reactivity was not noted in either system with strains of group A or group C rotaviruses or with other members of the family Reoviridae. These results indicate that GBRs contain both group-reactive and species-specific antigens which are distinct from those found in group A rotaviruses. The availability of well-defined immunoreagents will facilitate detailed studies of GBR infections in humans and animals.

Enzyme immunoassay for detection of human immunodeficiency virus antigens in cell cultures

A sensitive and specific avidin-biotin enzyme immunoassay that uses immunoreagents from naturally infected individuals was formulated for the detection of human immunodeficiency virus (HIV) antigens. A total of 500 cell culture samples from 111 cultures were tested in this assay and in a reverse transcriptase (RT) assay. Of 353 samples that were positive in the immunoassay, 174 were positive and 179 were negative in the RT assay. The specificity of the immunoassay results was supported by the failure of samples to react with nonimmune serum, by the ability of an anti-HIV type 1 monoclonal antibody to block the reactivity of selected samples, and by the appearance of RT activity in samples drawn from some cultures after a longer period of cultivation. HIV antigens were detected in 174 of 176 RT-positive samples (sensitivity, 98.9%). A comparison of the kinetics of antigen production and RT activity revealed that detectable antigen levels frequently preceded the appearance of RT activity. Thus, 50% of virus-containing cultures were identified within 9 days by immunoassay compared with 14 days by RT assay. In addition, RT activity was often detected intermittently in cultures sampled on several days, whereas antigen levels did not decline after initial appearance. Enzyme immunoassays for HIV antigen detection that use easily obtained reagents and simple technologies could facilitate laboratory and clinical research which requires cultivation of viruses.

Effect of continued oral feeding on clinical and nutritional outcomes of acute diarrhea in children

One hundred twenty-eight nonmalnourished male patients between 3 and 36 months of age were randomly assigned to receive one of four lactose-free dietary treatments to determine the effect of dietary therapy on the severity and nutritional outcome of diarrheal illness. Group 1 received a formula diet composed of casein, sucrose, dextrin with maltose (Dextri-Maltose), and vegetable oil to provide 110 kcal/kg body weight/d (CSO-110). Group 2 received CSO to provide 55 kcal/kg/d (CSO-55) for 2 days and then CSO-110. Group 3 received only oral glucose-electrolyte solution (GES) for 2 days, CSO-55 for the next 2 days, and then CSO-110. Group 4 received the same diets as Group 3 except that only intravenous GES was used for the first 2 days. The GES maintenance solutions provided 24 to 30 kcal/kg/d. Therapeutic success rates were similar among dietary groups, ranging from 90% to 97%. Fecal excretion was initially lower in group 4 (P less than 0.05) but was similar initially among groups treated orally and among all four groups beginning on day 3. Net apparent absorption of nitrogen, fat, carbohydrate, and total energy; retention of nitrogen; and increments in body weight, arm circumference, and skin-fold thickness were positively related to the amounts of dietary energy consumed. Thus continued oral feeding with the CSO diets during the early phase of therapy yielded improved nutritional results.

Epitope-specific immune responses to rotavirus vaccination

Rotavirus gastroenteritis is a leading cause of infant mortality in developing countries and an important cause of morbidity in children under 2 yr of age in the United States. Vaccine programs have evaluated animal rotavirus strains that are attenuated in humans but antigenically similar to some human strains. Whether a single vaccine strain can elicit protective immunity in humans to rotaviruses of the same or different serotypes is an important question in determining vaccine efficacy. We used characterized serotype-specific monoclonal antibodies directed at VP7 in a competitive solid-phase immunoassay to measure epitope-specific immune responses to serotypes 1, 2, and 3 in sera of children who received a candidate serotype-3 rotavirus vaccine. Antibodies to serotype 3 were detected in 72% of sera samples, and to serotype 1 and 2 in only 11% each. Also, a VP3-specific monoclonal antibody which neutralizes three serotypically distinct strains of rotavirus was used to detect the presence of similar antibodies in 56% of the test sera. This finding suggests a mechanism of heterotypic immunity.

Specificity of dot hybridization assay in the presence of rRNA for detection of rotaviruses in clinical specimens

Nucleic acid hybridization is used to identify viral genomic sequences in clinical and environmental samples. However, RNA virus genomes have been reported to hybridize to mammalian rRNA from uninfected cells under stringent conditions, and caution has therefore been advised in the use of nucleic acid probes for detection of RNA viruses. To evaluate the effect of rRNA on a diagnostic assay for an RNA virus, we tested the specificity of a rotavirus dot hybridization assay with clinical specimens which contained eucaryotic rRNA. The cDNA probe used in this assay contained sequences complementary to all 11 rotavirus genes. Preliminary experiments indicated that hybridization between rRNA and the cDNA probe occurred only with greater than 50 ng of rRNA, and this interaction was easily distinguished from the hybridization of the rotavirus probe with homologous or heterologous strains of the same rotavirus group. When 95 clinical specimens were tested, the rotavirus dot hybridization assay had a specificity of 98.8%. The predictive value of a negative test was 94.2%, although nearly all of the specimens contained rRNA and also reacted with an rRNA probe. Although the specificity of all dot hybridization assays should be individually evaluated, we conclude that our dot hybridization assay for rotaviruses is highly specific even in the presence of quantities of rRNA that may be anticipated in extracts of fecal specimens.

Safety and immunogenicity of bovine rotavirus vaccine RIT 4237 in 3-month-old infants

To assess the safety and immunogenicity of bovine rotavirus vaccine, we administered attenuated strain RIT 4237 to 54 inner-city infants randomized to one of three groups in a double-blind fashion to receive a dose at 3 and 5 months of age of either placebo, vaccine virus at 10(7) TCID50/ml, or vaccine virus at 10(8) TCID50/ml. Vaccination began in early fall 1984, and continued through spring 1985. Forty-nine infants received one dose of vaccine or placebo; 43 received both doses of vaccine or placebo. At 2 and 3 months after vaccination, homologous geometric mean neutralizing antibody titers were significantly higher in children who received either dose of vaccine compared with placebo recipients. Cumulative seroconversion to bovine rotavirus after either dose of vaccine virus was 87% at 6 months of age. Seroconversion was significantly higher (P less than 0.01) in both vaccine groups compared with the placebo group. No ill effects were associated with vaccine administration. RIT 4237 vaccine appears to be safe and immunogenic when administered to young infants living in the United States.

T-cell-deficient mice display normal recovery from experimental rotavirus infection

Rotaviruses are common causes of diarrhea in animals and humans. Little is known, however, about the components of the host response to these viruses. Rotavirus infection was studied in athymic mice experimentally infected with murine rotavirus. Neonatal T-cell-deficient mice experienced a self-limited gastrointestinal infection which was identical to that observed in age-matched immunocompetent mice. Adult T-cell-deficient seronegative mice and age-matched normal mice showed a similar extent of resistance to symptomatic rotavirus infection. In both cases, the infection was resolved without the generation of antirotavirus antibody. These studies indicate that host defense against murine rotavirus requires neither functional T-lymphocytes nor specific antiviral antibody.

Role of soy-based, lactose-free formula during treatment of acute diarrhea

A controlled study was conducted comparing the standard method of treating hospitalized infants with acute diarrhea (limited starvation) with the initiation of "early feeding" using a soy-based, lactose-free formula in infants of an American Indian tribe 12 months of age or younger. Forty-three patients, randomly assigned to group A, were given a soy-based, lactose-free formula four hours after hospitalization, and 44 patients, randomly assigned to group B, received standard therapy (food was withheld for the first 48 hours of hospitalization). After the first 48 hours, the same soy-based, lactose-free formula was given to the group B patients. Fluid intake and output of stool, urine, and vomitus were measured until the diarrhea resolved. Overall, group A patients showed less mean stool output (121 +/- 129 (SD) mL/kg) than group B patients (299 +/- 319 mL/kg) (P less than .001). Furthermore, the duration of illness was significantly shorter in group A patients (54 +/- 28 hours v 93 +/- 56 hours) (P less than .001). It was concluded that soy-based, lactose-free formulas can be safely used during the acute phase of diarrheal illness in infants and that their use shortens the duration of illness and decreases stool output in comparison with standard therapy.

Detection of enteric adenoviruses by dot-blot hybridization using a molecularly cloned viral DNA probe

Enteric adenoviruses (EAds) (candidate adenoviruses 40 and 41, subgroups F and G) have been implicated in the etiology of gastroenteritis in infants, but their clinical significance has been unclear because a rapid test to distinguish these agents from other adenovirus (Ad) types has not been available. We developed a dot-blot hybridization assay for EAd DNA using a cloned DNA fragment that has little homology to non-EAd DNAs. The dot-blot system detected less than 20 pg of EAd DNA, while showing minimal cross hybridization to representative strains from all other Ad groups. There was no detectable hybridization to extracts of samples known to contain other enteric viruses. It was further shown that low levels of EAds in specimens could be amplified by culturing for 1 day in 293 cells. Stool samples and tissue culture lysates prescreened by electron microscopy, cell culture or ELISA were tested in a blind fashion. Using endonuclease analysis as the standard for typing the isolates, we found the dot-blot system to have a 91% sensitivity and 71% specificity for detecting EAds and distinguishing them from other Ads. False-positive and equivocal dot-blot results appeared to be caused by other Ads.

Rapid diagnosis of viral infections: a new challenge for the pediatrician

Pediatricians are likely to encounter a limited number of viruses causing a significant number of problems. Many of these infections, such as the common cold, do not currently require specific viral diagnosis. On the other hand, the rapid diagnosis of some viral infections has become clinically and epidemiologically more important as a result of improved understanding of viral transmissability and recent developments in preventive and therapeutic approaches. Concomitantly, several new diagnostic methods have been applied to many of these agents with increasing numbers of commercial kits. This double-edged sword of the predictably greater availability of means to obtain a rapid specific diagnosis of many viral infections, together with the various problems discussed here which can lead to erroneous management of patients, is becoming an important new challenge to the pediatrician.

A search for cytomegalovirus and herpes viral antigen in brains of schizophrenic patients

The peroxidase-antiperoxidase method was employed to search for evidence of cytomegalovirus (CMV) or herpes simplex virus (HSV) antigen in the brains of 25 patients with a diagnosis of schizophrenia, 25 nonschizophrenic neuropsychiatric patients, and 16 nonpsychiatric control subjects. Brain specimens from patients with acute CMV and herpes encephalitis served as positive controls. Although early results with low-titer CMV antisera suggested immunoreactivity in specific brain regions of a small number of schizophrenic and control cases, the present studies with high-titer anti-CMV IgG did not give a positive immunoperoxidase reaction in sections from the basal forebrain, hypothalamus, or midbrain. Scattered neurons in the lateral vestibular nucleus and hippocampus showed questionable staining with CMV IgG in one schizophrenic patient and none in control subjects. No schizophrenic or control cases demonstrated an immune reaction to HSV antisera.

Serum antibody response to toxins A and B of Clostridium difficile

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to toxins A and B of Clostridium difficile was developed. Serum samples from 340 patients were tested for determination of the age-related prevalence of antitoxin. Antibody to toxin A was present in 64% of patients more than two years old and antibody to toxin B in 66% of patients more than six months old. A strongly positive ELISA value correlated with the presence of cytotoxicity-neutralizing antibody (P less than 0.001). Strongly positive ELISA values were obtained more commonly in convalescent sera from 16 patients with C difficile-induced colitis than in sera from the control population (antibody to toxin A, P less than 0.05; antibody to toxin B, P less than 0.001). Testing of paired sera revealed significant increases in the titer of IgG antibody to toxin A or B. Ten of the 16 patients with colitis had IgM titers of greater than or equal to 1:160 to one or both toxins. The data presented suggest that antibodies to toxins A and B are present in the majority of older children and adults and that patients with C difficile-induced disease develop serologic responses to one or both toxins.

Clostridium difficile in normal infants and sudden infant death syndrome: an association with infant formula feeding

Large numbers Clostridium difficile were found in the stools of two victims of sudden infant death syndrome (SIDS). This prompted a study of normal infants in the SIDS age group. Thirty-two infants were studied, using two selective culture techniques and two assays for bacterial products. Thirteen of the normal infants (39%) were found to carry C difficile, and fecal toxins were detected in eight of these, four with cytotoxin detectable at 10(-4) or higher dilution. Colonization was observed in one of 13 (7%) breast-fed babies and 12 of 17 (71%) of those whose primary milk source was infant formula (P less than .01). Fecal C difficile toxin was detected only in the latter group. The isolation of C difficile or its toxins in the stools of infants with SIDS, diarrhea, or even if large quantities of fecal cytotoxin are present.

Enzyme-linked immunosorbent assay (ELISA) for the detection of antibody to cysticerci of Taenia solium

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibody to cysticerci of Taenia solium has been developed that employs a pork muscle antigen control for the cysticercus test antigen, somewhat improving the serological distinction between infected and uninfected subjects. Serum antibody to cysticercus was detected in 79% of classical neurocysticercosis patients from Mexico, and in 61% of a group of cysticercosis patients with an unusually rapid invasion of the central nervous system in an endemic focus of disease in Irian Jaya. Antibody was absent in a group of healthy American laboratory personnel, and in residents of a non-endemic region of Papua New Guinea. Additional test on sera from patients with other parasitic diseases showed that cross-reactivity may occur in some patients with schistosomiasis, echinococcosis, and possibly angiostrongyliasis; however, these parasites are not known to cause human infection in Irian Jaya.

Sudden infant death syndrome associated with rotavirus infection

Rotavirus was detected in the stools of five children stricken with sudden infant death syndrome (SIDS) over a three-week period. While none of the children had acute gastroenteritis, four of the five had acute upper respiratory infections. Rotavirus was also identified in tracheal aspirates from two of the infants. Extensive investigations failed to reveal the presence of any other viruses or toxins in specimens obtained from the five children with SIDS. Rotavirus was not found in the stool specimens obtained from a control group of 36 infants including six who died of causes other than SIDS. Future attempts at the prevention of rotavirus infections should be directed at populations susceptible to sudden infant death syndrome.