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Biomedical subjects

C A Hart

Publications and source records attributed to C A Hart.

At least 325 records · Page 18Linked to original sources
PubMed1991

The effect of a self-regulating trace heating element on Legionella within a shower.

A self-regulating trace heating element was assessed for its ability to maintain a temperature of 50 degrees C in the mixer valve and dead-legs of a shower, and for its effect on legionellas colonizing the shower. The trace heating element maintained a temperature of 50 degrees C +/- 1.5 degrees C in dead-legs when the circulating hot water supply remained above 45 degrees C. Legionellas appeared in a trace heated dead-leg when the temperature of the dead-leg reached 45 degrees C and the hot water supply dropped below this temperature. Legionellas were eradicated or significantly reduced in sections of the shower where a temperature of 50 degrees C was consistently achieved. The mixer valve which was trace heated but not insulated remained colonized with Legionellas. Legionellas were found in shower water throughout the study.

Equipment Contamination↗
PubMed1991

The prevalence of enteric pathogens in diarrhoeic thoroughbred foals in Britain and Ireland.

A survey of 77 normal and 326 diarrhoeic foals in Britain and Ireland from 1987 to 1989 revealed a significantly higher prevalence of Group A rotaviruses and Aeromonas hydrophila in diarrhoeic foals. The prevalence of cryptosporidia, potentially pathogenic Escherichia coli, Yersinia enterocolitica and Clostridium perfringens was similar in normal or diarrhoeic foals. Rotaviruses had a similar prevalence in all age groups of scouring foals up to three months of age, with an overall prevalence of 37 per cent among diarrhoeic foals. The number of cases of diarrhoea varied considerably from year to year, but in all three years of the survey rotavirus was a significant pathogen. A comparison of diagnostic tests for rotavirus in the faeces showed electron microscopy (EM) and polyacrylamide gel electrophoresis (PAGE) to have similar sensitivity. The Rotazyme ELISA test kit was found to have the same sensitivity as a combination of EM and PAGE. A. hydrophila had an overall prevalence of 9 per cent among diarrhoeic foals, although its prevalence was higher in some age groups. A. hydrophila has not been established previously as a significant enteric pathogen in foals. Other putative pathogens found at very low prevalence were coronavirus, the putative picobirnavirus, Campylobacter spp. and Salmonella spp. No evidence was found of synergistic effects between rotavirus, cryptosporidia and potentially pathogenic E. coli. Neither coccidia nor non-Group A rotaviruses were found in any of the samples examined.

Aeromonas↗
PubMed1991

Features and outcome in meningococcal disease presenting with maculopapular rash.

Sixty nine patients with meningococcal disease some of whom presented with a maculopapular rash were entered in a prospective multicentre study. The clinical and laboratory features of children presenting with maculopapular rashes were compared with those of children presenting with typical haemorrhagic rashes. Of the 69 children 26 (38%) developed maculopapular rashes; nine (13%) had a maculopapular rash only, and the remaining 17 had a mixed maculopapular-purpuric rash. Twelve of the 17 (7%) had less than 12 petechiae. Children with maculopapular rashes had significantly higher platelet counts (median 294 compared with 243 x 10(9)/l), and plasma total haemolytic complement activity (80.5 compared with 65.0 U/ml) and significantly lower Glasgow meningococcal septicaemia prognostic scores (2.5 compared with 5.5) than those with purpuric rashes on admission. There were no significant differences between the groups in mortality, white cell count or absolute neutrophil count on admission, or C reactive protein concentration. Meningococcal disease can present with a maculopapular rash alone but this does not necessarily mean that the disease is less severe.

Complement Hemolytic Activity Assay↗
PubMed1991

Evidence for herpes simplex viral latency in the human cornea.

Patients undergoing penetrating keratoplasty for prior herpes simplex keratitis (group A) and corneal disease unrelated to herpes simplex (group B) were investigated to assess whether the cornea is a site for herpes simplex viral latency. All patients were seropositive for herpes simplex viral antibody. Virus was isolated from the tear film postoperatively in one patient and on cocultivation from the cornea of another patient. Herpes simplex viral DNA, however, was detected in the corneas of all patients from group A and half of those from group B by means of the polymerase chain reaction and primers to three well separated regions of the viral genome. Three donor corneas had no evidence of herpes simplex viral DNA. Using RNA polymerase chain reaction, we found evidence of a latency associated transcript and also that of a glycoprotein C coding transcript in two corneas, indicating viral replication. Nine corneas had evidence of a latency associated transcript but no glycoprotein C transcript, which suggests that herpes simplex virus may be maintained in a latent state in the corneas of patients with prior herpes simplex keratitis and in some patients with corneal disease unrelated to the herpes simplex virus.

Adult↗
PubMed1991

Ceftazidime treatment in cystic fibrosis: resistant organisms in sputum and faeces.

Ceftazidime was used as the only intravenous agent for treating lower respiratory tract infections in patients with cystic fibrosis. The risks of inducing beta lactamases and conferring antibiotic resistance are high when monotherapy is used; so the emergence of resistant bacteria was studied prospectively in the sputum of 120 patients. The mean age of patients was 9.0 (range 0.3-25) years and there were equal number of male and female patients. Pseudomonas aeruginosa was the only ceftazidime resistant bacterium to be isolated from the respiratory tract, and was identified only in chronically colonised patients. Ceftazidime resistance occurred in 103 (14%) of 750 P aeruginosa isolates, and in 16 of 36 chronically colonised patients. Ceftazidime resistant organisms were isolated from the faeces of 17 of 64 patients investigated. Eighty two per cent of the resistant faecal organisms were single isolates: the same resistant organism in faeces was isolated from successive samples in only two patients. In no case was the ceftazidime resistant enteric isolate the same as that from sputum. Patients chronically colonised by P aeruginosa did not harbour ceftazidime resistant enteric organisms any more than non-colonised patients. The use of ceftazidime as a single intravenous agent in treating chest exacerbations in cystic fibrosis does not induce a reservoir of ceftazidime resistant bacteria.

Adolescent↗
PubMed1991

Effects of recombinant human granulocyte colony-stimulating factor on neutrophil function in vitro and in vivo following chemotherapy and autologous bone marrow transplantation.

Recombinant granulocyte colony-stimulating factor (rG-CSF) primed the ability of human neutrophils to generate increased levels of reactive oxidants in response to fMet-Leu-Phe, and also resulted in an increased rate of protein biosynthesis which was similar to that induced by granulocyte-macrophage colony-stimulating factor. However, rG-CSF reduced the chemotactic activity of neutrophils in response to endotoxin and did not result in an enhanced rate of killing of Staphylococcus aureus. rG-CSF was administered to patients after high dose chemotherapy and autologous bone marrow transplantation for the treatment of either Hodgkin's disease or multiple myeloma. This cytokine decreased the period of neutropenia following such treatment. Neutrophil function in two patients, measured seven days after the final administration of rG-CSF, was severely impaired as indicated by a greatly decreased ability to generate reactive oxidants. However, seven days later (i.e. 14 days post-therapy), the functional activity of the neutrophils from these patients had returned to normal. These data indicate that assays of neutrophil function together with morphological assessment of neutrophil numbers and maturity should be performed in order to evaluate the immune status of patients undergoing such therapy.

Bone Marrow Transplantation↗
PubMed1990

Variation in intracellular P1P4-bis(5'-adenosyl) tetraphosphate (Ap4A) in virus-infected cells.

The effect of virus infection on the intracellular concentration of the proposed stress alarmone P1P4-bis(5'-adenosyl) tetraphosphate (Ap4A) has been examined in Vero cells. Compared with exposure to 0.8 mM-Cd2+, which causes a 30-fold increase in Ap4A, infection with simian virus 40 and poliovirus causes only a 2-fold increase, whereas herpes simplex virus type 1 results in a decrease in Ap4A during the course of the infection.

Animals↗
PubMed1990

The efficacy of control measures for eradicating legionellae in showers.

The efficacy of secondary control measures on showers colonized with legionellae was assessed. Hyperchlorination of shower heads and angle valve strainers had only a short-lived effect on legionellae. Automatic drain valves fitted to showers were ineffective in maintaining a reduction in the number of legionellae in shower water. Regular flushing of showers reduced legionellae to below detectable levels. Removal of dead-legs from the feed-pipes supplying hot water to showers, resulted in a decrease in legionellae in these sites but an increase in legionellae colonizing mixer valve components.

Baths↗
PubMed1990

The role of psychiatric consultation liaison nurses in ethical decisions to remove life-sustaining treatments.

This article proposes a deliberative nursing process for ethical decisions about the withdrawal of life-saving treatments from terminally ill patients. It highlights the role of the psychiatric consultation liaison nurse in facilitating this process and the growing need for an expanded nursing role, presents relevant ethical theory and principles, and introduces a paradigm for such ethical decisions. As medical technology and life-saving equipment continue to proliferate, the psychiatric consultation liaison nurse can become increasingly involved in assisting all health care providers in the essential professional role of helping patients and families to make these ethical decisions.

Beneficence↗
PubMed1990

Viral gastro-enteritis in children in Malawi.

In a 2-month survey of 186 children with gastro-enteritis attending an out-patient clinic in Malawi, 42% were infected with rotavirus (HRV), 9% Cryptosporidium, 4.2% adenovirus, 1.2% Astrovirus and 0.6% Norwalk agent and small round featureless viruses. We believe this to be the first report of HRV in Malawi and the first of Astrovirus in Africa. Almost all the HRV infections were in children under 12 months old, 40% were in children under 6 months and 64% of children were being breastfed at presentation. Signs of respiratory tract infection were not unique to HRV gastro-enteritis. Polyacrylamide gel electrophoresis of HRV dsRNA from 25 of the faecal samples revealed that each had the same long electropherotype.

Adenoviridae Infections↗
PubMed1990

Attaching effacement of the rabbit enterocyte brush border is encoded on a single 96.5-kilobase-pair plasmid in an enteropathogenic Escherichia coli O111 strain.

An enteropathogenic Escherichia coli (EPE) O111 serotype a,b,H- strain carried the following four plasmids: pLV501 (96.5 kilobase pairs [kbp]) specifying resistance to chloramphenicol, tetracycline, and kanamycin; pLV502 (8 kbp) specifying ampicillin resistance; pLV503 (1.9 kbp) specifying streptomycin resistance; and pLV504 (80 kbp) with no resistance markers. This EPEC attached to HEp-2 cells to produce localized clumps of bacteria (localized adhesion) and attached intimately to the enterocyte surface, leading to loss of the brush border (attaching effacement). Plasmid pLV501 was also found to specify the ability to produce localized adhesion on HEp-2 cells and attaching effacement in a rabbit ileal explant model system. Restriction maps showed considerable dissimilarities between pLV501 and pMAR-2, an EPEC plasmid carrying the EPEC adherence factor (EAF) genes. Furthermore, pLV501 did not hybridize with the EAF probe, whereas pLV504 did. There was sequence homology between pLV501 and large plasmids in all seven other well-characterized EPEC, only five of which hybridized with the EAF probe. These findings indicate that pLV501 carries at least one of the genes responsible for production of the brush border damage characteristic of EPEC.

Animals↗
PubMed1990

Ocular shedding of herpes simplex virus.

The presence, frequency, and relationship of ocular and oral shedding of herpes simplex virus to previous herpes keratitis was investigated. This was to determine if a history of herpes keratitis predisposes to shedding of the herpes simplex virus into the tear film and/or mouth. Swabs were collected from the eyes and mouth of two groups of patients thrice weekly over a two- to four-month period. Group A comprised nine patients with a history of herpes labialis, group B 15 patients with a history of herpes keratitis. Herpes simplex virus type 1 was isolated from 1.33% of mouth specimens but was not identified in any of the ocular specimens. There was no significant difference between groups A and B in terms of ocular or oral shedding. Oral shedding appears to be independent of a previous herpes keratitis. The tear film is an unlikely source of virus in persons either with no history of herpes keratitis or between attacks in those patients with a history of previous herpes keratitis.

Adult↗
PubMed1990

Comparison of four methods for detection of rotavirus in faeces.

Faecal samples from 325 children with gastroenteritis and 23 children without gastroenteritis were examined for the presence of human rotavirus (HRV) using four different methods. Using the WHO-ELISA, HRV was found in the stools of 98 (30%) symptomatic and 2 (9%) asymptomatic children. A latex particle agglutination test had the highest sensitivity (92%) but the lowest specificity (96%). Both electron microscopy and polyacrylamide gel electrophoresis of HRV RNA (RNA-PAGE) were highly specific (100%) but of lower sensitivity (73% and 84% respectively). Of the four methods tested latex particle agglutination is the simplest and since it requires little extra equipment is ideally suited for bedside tests in tropical countries. It is, however, not cheap. An alternative is to use RNA-PAGE which will require some equipment and a power supply but which is relatively cheap and will also provide epidemiological data.

Child↗
PubMed1990

Inhibition of neutrophil superoxide secretion by the preservative, methylhydroxybenzoate: effects mediated by perturbation of intracellular Ca2+?

The preservative, methylhydroxybenzoate inhibited O2- secretion from human neutrophils activated by both the chemotactic peptide fMet-Leu-Phe and phorbol myristate acetate (PMA): the low level of oxidant secretion activated by the ionophore A23187 was similarly reduced in preservative-treated suspensions. Oxidant secretion was similarly reduced in fMet-Leu-Phe and A23187 treated suspensions in which intracellular Ca2+ was buffered by loading with Quin-2, indicating that methylhydroxybenzoate may exert its effects by perturbation of intracellular Ca2(+)-dependent processes. Methylhydroxybenzoate could mimic EGTA in preventing the Ca2+ dependent enhancement of trypsin activity and could also bind this cation in experiments using a Ca2+ electrode, although the preservative bound Ca2+ more slowly and had a lower affinity than EGTA. These data indicate that methylhydroxybenzoate may exert its effects on neutrophils by perturbation of Ca2(+)-dependent activation pathways and this phenomenon may also explain its other known pharmacological effects. Furthermore, these observations provide an insight into the mechanisms by which intracellular Ca2+ may regulate oxidant secretion.

Calcium↗
PubMed1990

Acute meningococcal infection--a case of monoarthrosis.

A case of septic arthritis in the right knee of a six-month-old girl is described. Neisseria meningitidis was grown from the purulent exudate from the knee joint. No other manifestations of meningococcal disease were observed. Complete recovery followed aspiration and treatment with benzyl penicillin.

Acute Disease↗