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Biomedical subjects

P Woods

Publications and source records attributed to P Woods.

At least 19 recordsLinked to original sources

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

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

Serotypes and electropherotypes of human rotavirus in the USA: 1987-1989.

The epidemiology of rotavirus gastroenteritis was investigated for two consecutive seasons (1987-1988 and 1988-1989) in seven locales in the continental USA. The 281 representative fecal samples obtained from children with diarrhea were electropherotyped and serotyped by an enzyme immunoassay with serotype-specific monoclonal antibodies and a new amplification typing technique (polymerase chain reaction typing). Serotype 1 was predominant in both years, particularly in the North and East; serotype 3 was second in frequency and found most often in the South; serotype 2 was detected only occasionally; serotypes 4, 8, and 9 were never found. Rotavirus strains were grouped into five major electropherotypes, each corresponded to a single serotype, and the relative migration of the gene segments 7-9 could be used to distinguish serotype 1 from serotype 3. The amplification typing technique proved to be of great value in typing the 17% of rotavirus-positive specimens untypable by the serologic technique.

Antibodies, Monoclonal

Polymerase chain reaction amplification and typing of rotavirus nucleic acid from stool specimens.

The rotavirus gene segment coding for the major outer capsid glycoprotein vp7 was amplified directly from stool specimens by the polymerase chain reaction (PCR). Double-stranded RNA extracted from stool samples was used as the template for reverse transcription, which was followed immediately and in the same reaction mix with amplification, using the Taq polymerase. Various conditions were examined to optimize the yield of the amplified gene. The concentrations of MgCl2, dimethyl sulfoxide, and template RNA were critical. The choice of primer pairs allowed amplification of the entire segment or specific portions. By using type-specific primers derived from distinct regions on the gene, we devised a PCR typing method in which each human serotype virus produced a characteristic segment size, readily identifiable in agarose gels. The PCR typing method was applied to 10 rotavirus reference strains, including all 6 known human serotypes (serotypes 1, 2, 3, 4, 8, and 9), and to 34 stool specimens previously serotyped by an enzyme immunoassay with monoclonal antibodies. An absolute correlation was found between the molecular and serologic methods. In addition, 14 stool specimens nonserotypable by an enzyme immunoassay with monoclonal antibodies could be typed by the PCR method. Besides the application for rotavirus detection and typing directly from stools, the PCR method provides a rapid and efficient means of obtaining large quantities of cDNA suitable for sequencing, cloning, and other genetic studies, precluding the need for cell culture and virus purification.

Base Sequence

Simultaneous administration of rhesus rotavirus vaccine and oral poliovirus vaccine: immunogenicity and reactogenicity.

Rotavirus vaccine could be administered most efficiently if it were incorporated into routine childhood immunizations and did not interfere with the immune response to the other vaccines, principally oral poliovirus vaccine (OPV). We conducted a placebo-controlled randomized trial giving oral rhesus rotavirus vaccine (RRV) (strain MMU 18006) alone and together with a child's first dose of OPV and diphtheria-tetanus toxoids-pertussis to examine the possible interaction of these vaccines. A total of 102 infants 2 to 3 months of age were randomized into 3 groups to receive (1) RRV with OPV, (2) placebo with OPV and (3) RRV 2 weeks after OPV. All infants were given diphtheria-tetanus toxoids-pertussis. Serum samples were collected at the time of OPV immunization and 3 to 5 weeks later. Three to 5 weeks after OPV immunization 60% of infants had a 4-fold rise in neutralization titer to at least one of the three poliovirus serotypes. The rate of antibody response to poliovirus did not differ by RRV groups but a lower rate was correlated with a shorter interval (3 vs. 5 weeks) between OPV vaccination and antibody measurement. Fifty-six percent of infants had a 4-fold rise of IgA and 62% had a 4-fold rise of neutralizing antibody to RRV; this rise did not differ according to time of OPV immunization. RRV was not associated with side effects and may be safely given with OPV to infants 2 to 3 months of age.

Antibodies, Viral

Sepsis associated with central vein catheters in critically ill patients.

In 440 critically ill patients, the association between different central vein catheter insertion sites, the duration of catheter insertion and catheter-associated sepsis was examined. Of 780 catheter tips studied, 19% were colonized by microorganisms. The incidence of colonization varied with the different insertion sites. The lowest percentage of colonized catheters occurred with catheters inserted via the subclavian vein (15%) and the highest, at the femoral vein insertion site (34%, p less than 0.01). The percentage of catheters colonized increased as the duration of insertion increased, at all insertion sites studied. Catheter colonization was closely related to the development of bacteraemia and was associated with approximately 10% of colonized catheters. Our results suggest that the subclavian site is associated with the lowest infective complication rate. To minimize catheter associated sepsis, catheters at all insertion sites should be used with parsimony and only kept in place for the minimum amount of time that their continuing use is necessary.

Catheterization, Central Venous

The management of injuries--a review of deaths in hospital.

A prospective review was undertaken of the management of 111 consecutive patients who died in hospital after admission for treatment of injuries. A standard set of data relating to each patient was reviewed by each member of a trauma death audit committee and then by the whole committee. Autopsy reports were available on all patients. Conclusions were drawn concerning defective aspects of patient management and possible avoidance of each death. Injury severity was assessed using the Trauma Score (TS) and Injury Severity Score (ISS). The possibly avoidable death (PAD) rate was 17%. The most common defects in management were related to inadequate fluid resuscitation and delays in definitive management. The greatest contributions to the PAD rate were from inadequate fluid resuscitation, delays and inadequate perception of the severity of injuries or significance of clinical deterioration. Increasing age was related to a higher frequency of PAD. PAD rate in the presence of severe head injury was 8%, but was 63% in the absence of a severe head injury. It is concluded that review of all trauma deaths is an achievable, beneficial and essential part of a hospital-based integrated trauma service. TS and ISS are not sufficiently sensitive to justify their use in selecting deaths for review. Improved blood volume replacement, earlier and more direct management and supervision by senior specialist staff, and elimination of causes of delay in patient management should all decrease the death rate from injuries particularly in patients without severe head injury.

Adolescent

Bone levels of cephradine and cefuroxime after intravenous administration in patients undergoing total hip replacement.

A randomised, comparative study is reported of single intravenous doses of cephradine 2 g or cefuroxime 1.5 g given as prophylactic cover for total hip replacements in 40 patients. The serum and bone levels of cephalosporin achieved were higher in the cephradine treated group in proportion to the higher dose employed. Both agents provided adequate bone levels on average, cephradine 25.34 mcg/g, cefuroxime 17.39 mcg/g, although bone penetration was more variable with cefuroxime.

Adult

Detection of antibodies to Mycoplasma felis in horses.

Mycoplasma felis has been isolated from horses with pleuritis, and limited research indicates that mycoplasma pleuritis can be reproduced in horses. The serodiagnostic potential of the indirect hemagglutination and the metabolism-inhibition tests was evaluated by testing 177 horses for antibodies to M felis. Seven horses with M felis pleuritis developed antibodies, and 6 horses with sterile or bacterial pleuritis had high titers suggesting a previous M felis infection. Six horses with pleuritis (one sterile and five bacterial) had low or no titers to M felis. Only one of 30 horses with conditions other than respiratory diseases seroconverted during hospitalization and the remaining horses had low titers. Seventy-eight foals, 4 to 6 months old, from one farm did not have titers, whereas 7 out of 50 yearlings from the same farm had high titers in the indirect hemagglutination test and titers in the metabolism-inhibition test. It appears that both tests are suitable for serodiagnosis of M felis infection in horses.

Animals