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R I Glass

Publications and source records attributed to R I Glass.

At least 163 records · Page 9Linked to original sources
PubMed1993

Enzyme-linked immunosorbent assay reactivity of torovirus-like particles in fecal specimens from humans with diarrhea.

Toroviruses are recognized enteric pathogens of cattle and horses; in humans, similar pleomorphic particles have been described, but doubt has been raised concerning their identity as viruses. We screened fecal samples from humans with diarrhea for the presence of torovirus-like particles (TVLPs) by electron microscopy and subsequently used an enzyme-linked immunosorbent assay (ELISA) with bovine torovirus reference reagents to test for the presence of torovirus antigens. To add another selection criterion to this heterologous ELISA, we enriched the TVLPs from the stool specimens by using sucrose density gradients before testing. The results of ELISA and EM correlated significantly, the ELISA having a sensitivity of 68% and a specificity of 86% (chi-square, P < 0.0001). In the gradient, peaks of ELISA reactivity were found at a buoyant density of 1.16 g/ml and were parallel to those found when using bovine torovirus. Furthermore, in 50% of the ELISA-positive gradients, a hemagglutinin for human group O erythrocytes comigrated with the peaks of ELISA reactivity. We were unable to isolate human TVLPs in human colonic tumor or rectal tumor cells. We cloned and sequenced amplification products obtained by low-stringency polymerase chain reaction amplification using consensus primers mapping to the 3' end of the genome of animal toroviruses, but found no significant homologies with animals torovirus sequences. Rabbits were inoculated with material from the gradient peak fractions of human stool specimens, and their sera were assayed for immunologic comparison with bovine torovirus as a reference. A two-way antigenic cross-reactivity was seen between human TVLP and bovine torovirus reagents when tested by ELISA. The rabbit antisera to human TVLP detected a higher number of electron microscopy-positive stool specimens than did the rabbit antisera to bovine torovirus. The application of these assays and reagents should help to elucidate the roles of TVLPs and toroviruses in diarrheal disease in humans.

Animals↗
PubMed1993

Detection of antibody to recombinant Norwalk virus antigen in specimens from outbreaks of gastroenteritis.

Norwalk virus and other small round-structured viruses are commonly associated with outbreaks of gastroenteritis. We used a recently described recombinant-expressed Norwalk virus (rNV) capsid protein in enzyme immunoassays to quantitatively measure immunoglobulin G (IgG) and IgA to Norwalk virus in serum pairs from patients involved in outbreaks of gastroenteritis. The outbreaks previously were classified, on the basis of the results of a blocking antibody assay, as Norwalk virus negative, serologically intermediate, or Norwalk virus positive. The rNV IgG assay was more sensitive than the blocking assay for detecting IgG to Norwalk virus in serum from patients in all outbreak classes. There was 79% concordance between seroconversions detected by the blocking antibody assay and those detected by the rNV IgG assay. The rNV IgA assay detected seroconversions to Norwalk virus primarily in patients involved in outbreaks previously classified as Norwalk virus positive.

Antibodies, Viral↗
PubMed1993

Subgenomic RNA sequence of human astrovirus supports classification of Astroviridae as a new family of RNA viruses.

We report the sequence of the subgenomic RNA of human astrovirus serotype 2. This 2,484-nucleotide RNA contains a single open reading frame, which encodes a protein with a predicted molecular mass of 88 kDa. We propose that this protein is the 90-kDa capsid precursor observed in infected cells. The deduced protein sequence does not contain conserved amino acid patterns reported for the capsid proteins of picornaviruses or caliciviruses, consistent with the classification of astroviruses as a new family of RNA viruses, designated Astroviridae.

Amino Acid Sequence↗
PubMed1993

National laboratory surveillance of viral agents of gastroenteritis in Brazil.

In 1984 an enzyme immunoassay for rotavirus and adenovirus developed in the Virology Department of the Oswaldo Cruz Foundation was distributed to laboratories in 14 Brazilian states as part of a project to survey viral agents in fecal specimens from children with diarrhea. The ensuing surveillance continued for 3 to 5 years, and in 1991 the results obtained by all laboratories that tested 300 or more fecal specimens were reviewed at a workshop held in Belém. These results showed that rotavirus had been detected in 13% to 20% of the specimens tested, with positive specimens appearing to peak in the May to September "winter" or dry season in Brazil's central and southern states but not in the more tropical northern areas. Adenovirus, detected in 0.7% to 5.5% of the specimens tested for it, showed no seasonal variations. Many other viral agents known to cause gastroenteritis (e.g., astrovirus, small round-structured viruses, calcivirus, and group C rotavirus) were detected at centers that used electron microscopy. Picobirnavirus, a novel agent not yet associated with gastroenteritis in humans, was found by polyacrylamide gel electrophoresis in specimens from a number of centers using this technique. Vaccines to prevent rotavirus that are currently under development would be of great use in Brazil, where rotavirus is the most common cause of childhood diarrhea. Improved diagnostics will be required to assess the importance of the other viral agents.

Acute Disease↗
PubMed1992

Acute hemorrhagic conjunctivitis due to enterovirus 70 in American Samoa: serum-neutralizing antibodies and sex-specific protection.

Acute hemorrhagic conjunctivitis due to enterovirus 70 has caused extensive outbreaks in tropical areas since 1969. Between December 1, 1990, and March 4, 1991, an outbreak of acute hemorrhagic conjunctivitis due to enterovirus 70 occurred in American Samoa, where an outbreak due to the same agent had occurred in 1981. A survey of 5% of the households (134 households, 1,095 individuals) was conducted throughout the island of Tutuila. The outbreak affected 58% of the population, with age-specific attack rates greater than 50% for all age groups except children younger than 2 years. Attack rates were significantly higher for children 2-10 years old (65%) than in the remainder of the population. Women aged 21-40 years had higher rates than did men the same age (66 vs. 49%), possibly because of the close association of women and young children. At higher preepidemic titers, there was evidence of protection from clinical disease among males but not among females. Enterovirus 70 can cause large outbreaks even in a population already exposed in a previous large outbreak; protection due to previous infection is only partial.

Antibodies, Bacterial↗
PubMed1992

The management of acute diarrhea in children: oral rehydration, maintenance, and nutritional therapy. Centers for Disease Control and Prevention.

Worldwide, diarrhea remains one of the most common illnesses among children. In the United States, children < 5 years of age experience > 20 million episodes of diarrhea each year, leading to several million doctor visits, 200,000 hospitalizations, and approximately 400 deaths. Much of this morbidity is due to the dehydration associated with acute watery diarrhea. Consequently, the proper management of children with acute diarrhea is important for all practitioners as well as for parents of small children. The development of oral therapy for the rehydration and maintenance of children with dehydrating diarrhea has become the worldwide mainstay of national diarrheal control programs. More recently, proper nutrition for children with diarrhea is viewed as an important adjunct to therapy, whereas antibiotics and other drugs play only a limited role. Intravenous therapy remains essential for diarrheal episodes associated with severe dehydration. This document reviews the proper management of diarrhea among children. Particular attention is given to the use of oral therapy for rehydration and maintenance therapy for the dehydrated child and nutritional management. In the United States, the improved management of children with diarrhea could lead to a noticeable decrease in the number of children who are hospitalized or die as a result of diarrheal illness. This report contains recommendations prepared by the Centers for Disease Control and Prevention (CDC), with input from a panel of pediatric and diarrheal management experts, which are consistent with recommendations endorsed by the American Academy of Pediatrics.

Acute Disease↗
PubMed1992

Laboratory-based surveillance for rotavirus United States, January 1989-May 1991.

Geographic and temporal trends of rotavirus detections in the United States for the period January 1989-May 1991 were determined by analyzing data reported monthly by 47 virology laboratories participating in the North American Rotavirus Surveillance System. Reports included complete information on the number of specimens tested, the number of test results positive for rotavirus, and the method used to detect rotavirus. Consistent trends in regional and geographic area were identified, with distinctly different peaks of rotavirus activity in the western and eastern states. Each year in the western states, rotavirus activity began in November and peaked in December-January, whereas in the eastern states activity began in January and peaked in February-March. These differences do not correlate with obvious trends in strain variation of rotavirus and remain unexplained. Unexpected reporting of summer rotavirus activity by some laboratories in 1989 was traced to the use of a single diagnostic kit and to two questionable laboratory practices: having more than six medical technologists perform the test and failure to use controls with the test. Laboratory-based surveillance of rotavirus activity has proven to be useful in identifying and correcting problems in laboratory methods for detecting rotavirus and will be a sensitive means for monitoring coverage of the rotavirus vaccine now being developed.

Child, Preschool↗
PubMed1992

Hospitalizations involving gastroenteritis in the United States, 1985: the special burden of the disease among the elderly.

While diarrheal disease is a well-recognized problem in children, its impact in the elderly has not been adequately assessed. Among the 4.06 million hospitalizations in 1985 in the McDonnell-Douglas Health Information System database, 98,185 hospitalizations, including 1,130 deaths, had gastroenteritis recorded as a discharge diagnosis. The authors analyzed the 87,181 hospitalizations and 514 deaths for which gastroenteritis was one of the top three diagnoses. Gastroenteritis was among the top three diagnoses in 9% of all hospitalizations of children 1-4 years of age, compared with 1.5% of hospitalizations throughout adulthood (greater than or equal to 20 years). Only 0.05% of hospitalizations involving gastroenteritis were fatal for children younger than 5 years, compared with 3% in individuals 80 years or older. While children aged less than 5 years and adults aged 60 years or more each comprised one-fourth of hospitalizations involving gastroenteritis, the older group represented 85% of diarrheal deaths. Age was the most important risk factor for death subsequent to a hospitalization involving gastroenteritis (odds ratio = 52.6, 95% confidence interval 37.0-76.9 for age greater than or equal to 70 years vs. less than 5 years). Gastroenteritis is a large, underemphasized public health problem among the elderly, among whom its case-fatality ratio is higher than in children.

Adolescent↗
PubMed1992

Coding assignments of the genome of adult diarrhea rotavirus.

Adult diarrhea rotavirus (ADRV) has caused epidemics of diarrhea in China since 1982 and remains the only group B rotavirus associated with widespread disease in humans. We recently characterized the proteins of ADRV and have now proceeded to identify the gene segments encoding each protein. Viral RNA transcripts were synthesized in vitro with the endogenous viral RNA polymerase and separated by electrophoresis in agarose. The individual transcripts were translated in a cell-free system using nuclease-treated rabbit reticulocyte lysates. The translation products were compared with polypeptides found in purified virus and were characterized by SDS-PAGE, immunoprecipitation, and Western blot analysis using antisera to double- and single-shelled virions, virus cores, and monoclonal antibodies. Furthermore, individual RNA transcripts were hybridized to total dsRNA to determine their genomic origin. Based on this analysis, the core polypeptides VP1, VP2 and VP3 are encoded by segments 1, 2, and 3, respectively. The main polypeptides in the inner capsid, VP6, and the outer capsid, VP4 and VP7, are encoded by segments 6, 4, and 8 respectively. Segments 5, 7, and 9 code for 60, 45, and 30 kDa nonstructural polypeptides. Two other nonstructural polypeptides (24 and 25 kDa) are derived from gene segment 11. Gene segment 10 codes for a 26 kDa polypeptide that is precipitated with serum to ADRV and may be a structural protein VP9. With this exception, gene coding assignments of ADRV are comparable to those of the group A rotaviruses. Our results have clear implications for further work in cloning, sequencing, and expression genes of ADRV and can provide direction towards understanding the origin and the evolution of this virus.

Animals↗
PubMed1992

Nucleotide sequence of gene 5 encoding the inner capsid protein (VP6) of bovine group C rotavirus: comparison with corresponding genes of group C, A, and B rotaviruses.

To further study the molecular characteristics of group (gp) C rotaviruses, we produced, cloned, and sequenced cDNA to gene 5 of the Shintoku strain of bovine gp C rotavirus. The resulting clone was specific for gene 5 and was genetically related to the human and porcine gp C rotaviruses, as demonstrated by Northern blot hybridization analysis. The Shintoku gene 5 is 1352 nucleotides in length and has one open reading frame encoding a polypeptide of 395 amino acids with a predicted molecular mass of 44.5 kDa. Comparative sequence analysis indicated that: (i) the Shintoku gene 5 protein shared 88.4 to 90.6% homology with the VP6 of the human (Bristol and 88-220) and porcine (Cowden) strains of gp C rotaviruses, but only low homology with the VP6 of bovine gp A (RF) and human gp B (ADRV) rotaviruses (41.3 and 16.3%, respectively); (ii) the predicted secondary structure was highly conserved among the gene 5 proteins of the bovine, porcine, and human gp C rotaviruses; and (iii) seven highly conserved regions were identified for the first time in the deduced primary amino acid sequences of gene 5 of gp C and gene 6 of gp A rotaviruses. However, only three of these highly conserved areas were present in the regions of VP6, where the secondary structure was predicted to be similar for the rotavirus strains examined. These three regions may contribute to common epitopes between the two groups of rotaviruses. Our results, in comparison with data for other rotaviruses, indicate that gene 5 of the bovine gp C rotavirus codes for the major inner capsid protein (VP6).

Amino Acid Sequence↗
PubMed1992

Outbreaks of summer rotavirus linked to laboratory practices. The National Rotavirus Surveillance System.

In temperate regions rotavirus diarrhea is a disease of the cooler months of the year, but little is known about its patterns in the summer. We report on the first year of national surveillance of rotavirus, during which we actively investigated patterns of summer activity. We obtained data on rotavirus testing from 85 laboratories in 48 states, conducted a survey of their testing practices and retested for confirmation positive specimens from laboratories reporting high rates of positivity during the summer. During 1989 participating laboratories reported 4011 specimens tested for rotavirus during July and August, of which 436 (11%) were said to be positive. Most laboratories reported low rates of positivity during these months (median percent positive, 3), but five had very high rates of summer positivity (> 30%). These five laboratories were geographically separated, and neighboring laboratories showed little rotavirus activity. Positive specimens submitted by four of these centers with high rates of summer rotavirus could not be confirmed. A survey of laboratory methods found one commercial assay (TestPack) and two laboratory practices (failure to use controls and involvement of more than six technicians in the testing process) to be associated with high rates of summer positivity. Moderate rates of positivity (11 to 30%) were fond frequently in the southwest during July and August; reference testing of specimens from these laboratories confirmed positivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Laboratory Techniques↗
PubMed1992

Rotavirus diarrhea in Bangladeshi children: correlation of disease severity with serotypes.

To improve the understanding of the relative importance of serotypes of rotavirus in dehydrating diarrhea, we examined the correlation of clinical characteristics and disease severity with serotype in 2,441 diarrheal episodes among children younger than 2 years of age in rural Bangladesh. Of 764 rotavirus-associated episodes, a single G type (serotype 1, 2, 3, or 4) was determined by oligonucleotide probe in 485 (63%), while 233 episodes were nontypeable. Episodes with G types 2 and 3 were associated with more-severe dehydration than episodes associated with G type 1 or 4 or with nontypeable rotavirus. Episodes did not differ by G type in prevalence of vomiting, copious diarrhea, fever, abdominal pain, or length of treatment center stay. Rotavirus reinfections were detected in seven children, with homologous reinfection (G type 2) in one. Twelve children with diarrhea who died had rotavirus detected in stool specimens within 30 days of death. Children who died were more likely to be malnourished than were surviving children with rotavirus diarrhea. Of 40 specimens tested by polymerase chain reaction, 29 (72.5%) were P type 1, 9 (22.5%) were P type 2, 1 (2.5%) was P type 3, and 1 (2.5%) was nontypeable. One severely symptomatic diarrheal episode was associated with P type 3 rotavirus, a serotype usually found in asymptomatic nursery infections. Although G types 2 and 3 were associated with more-severe dehydration than other serotypes, the differences do not appear to be of major clinical importance. Effective vaccines should protect against all four major G types.

Bangladesh↗
PubMed1992

Distribution of serotypes of human rotavirus in different populations.

Serotyping is a useful tool to study the epidemiologic characteristics of rotaviruses in large populations and to assess the need for a vaccine to protect against all strains. By using an enzyme immunoassay with serotype-specific monoclonal antibodies to the four most common rotavirus serotypes, we analyzed 1,183 rotavirus-positive specimens from 16 stool collections in eight countries on four continents that were obtained from 1978 to 1989. Of the 926 strains (78%) that could be serotyped, 48% were serotype 1, 8% were serotype 2, 15% were serotype 3, and 7% were serotype 4. Twenty-two percent had insufficient numbers of double-shelled virus particles to react with the monoclonal antibody of the VP4 rotavirus protein and therefore could not be serotyped. Our results indicate that vaccines being developed must provide the greatest coverage against serotype 1 and that the serotype distribution cannot be predicted currently by the geographic area or prevalence in the preceding year.

Antibodies, Monoclonal↗
PubMed1992

Identification of group A rotavirus gene 4 types by polymerase chain reaction.

Five genetically distinct human rotavirus (HRV) gene 4 groups have been described on the basis of comparative nucleotide sequencing and the predicted amino acid sequences, and at least four of them represent distinct VP4 antigenic types. To identify each gene 4 type and investigate its distribution in HRV isolates from patients with diarrhea, we developed a polymerase chain reaction (PCR) typing method using sequence information available for four genetically distinct gene 4 types. Rotavirus double-stranded RNAs (dsRNAs) isolated from stool samples were first reverse transcribed and amplified by PCR by using two oligonucleotide primers that correspond to regions that are highly conserved among all known HRV gene 4 types. The 876-bp dsDNA products were then reamplified by PCR in the presence of a cocktail containing one conserved plus-sense primer and four type-specific minus-sense primers (selected from the hypervariable region of gene 4), resulting in products of 345, 483, 267, and 391 bp corresponding to gene 4 types 1, 2, 3, and 4, respectively. This method reliably identified the gene 4 types of 16 well-characterized HRV isolates. Our results were independently confirmed for all 16 strains by reverse transcription and PCR amplification of HRV dsRNA in the presence of alternate type-specific primer pairs. For direct gene 4 typing of HRV in stool samples, we developed a method to extract rotavirus dsRNA from stool specimens by using glass powder. Our results suggest that gene 4 typing will be useful in providing more a complete characterization of HRV strains of epidemiologic or vaccine-related interest.

Base Sequence↗
PubMed1992

The magnitude of the global problem of diarrhoeal disease: a ten-year update.

In order to update global estimates of diarrhoeal morbidity and mortality in developing countries, we carried out a review of articles published from 1980 to the present and calculated median estimates for the incidence of diarrhoea and diarrhoeal mortality among under-5-year-olds. The incidence of diarrhoea obtained (2.6 episodes per child per year) was virtually the same as that estimated by Snyder & Merson in 1982, while the global mortality estimate was lower (3.3 million deaths per year; range, 1.5-5.1 million). The mortality estimate is based on a small number of active surveillance and prospective studies, and thus associated with a large degree of uncertainty, reflecting the weakness of the global database. However, many surveys reporting reductions in mortality in several locations are consistent with a decreased estimate for mortality. More accurate execution of WHO survey methods, including population-based sampling in representative locations, and repeat surveys every 5 years, are needed to monitor the progress of diarrhoeal disease control programmes and trends in diarrhoeal morbidity and mortality over time.

Child, Preschool↗
PubMed1991

Cholera in Africa: lessons on transmission and control for Latin America.

In January, 1991, epidemic cholera emerged in Peru and spread to 7 other countries of Latin America. Cholera was introduced 20 years ago to Africa, where it spread rapidly to 30 of the 46 countries of the region and by 1990 accounted for 90% of all cases reported to the World Health Organisation. Many lessons from the cholera epidemic in Africa are relevant to efforts to control the disease in Latin America. Public health practices from the past--quarantine and cordon sanitaire to halt introduction of cholera by travellers, and vaccination and mass chemoprophylaxis to control epidemics--are ineffective in preventing spread of the disease. Cholera can be transmitted not only by contaminated water but also by food. Social phenomena such as mass migrations and burial practices may play a greater role than previously understood. While efforts to prevent the spread of cholera have been ineffective, cholera-associated mortality can be decreased with rehydration therapy. Since the current pandemic is unlikely to retreat soon, new strategies are urgently needed to control the spread of cholera through sanitary and behavioural interventions or improved vaccines.

Africa↗