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Biomedical subjects

S Hunter

Publications and source records attributed to S Hunter.

At least 19 recordsLinked to original sources
PubMed2006

PulseNet USA: a five-year update.

PulseNet USA is the molecular surveillance network for foodborne infections in the United States. Since its inception in 1996, it has been instrumental in detection, investigation and control of numerous outbreaks caused by Shiga toxin-producing Escherichia coli O157:[H7] (STEC O157), Salmonella enterica, Listeria monocytogenes, Shigella spp., and Campylobacter. This paper describes the current status of the network, including the methodologies used and its future possibilities. The currently preferred subtyping method in the network is pulsed-field gel electrophoresis (PFGE), a proven highly discriminatory molecular subtyping method. New simpler sequencebased subtyping methods are under development and validation to complement and eventually replace PFGE. PulseNet is essentially a cluster detection network, but the data in the system will now also be used in attribution analyses of sporadic infections. The PulseNet platform will also be used as a primary tool in preparedness and response to acts of food bioterrorism.

Bacterial Typing Techniques↗
PubMed2005

Nationwide outbreak of listeriosis due to contaminated meat.

We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17.3, 95% CI 2.4-160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.

Adolescent↗
PubMed2005

Mitral repair best practice: proposed standards.

OBJECTIVES: To define best practice standards for mitral valve repair surgery. DESIGN: Development of standards for process and outcome by consensus. SETTING: Multidisciplinary panel of surgeons, anaesthetists, and cardiologists with interests and expertise in caring for patients with severe mitral regurgitation. MAIN OUTCOME MEASURES: Standards for best practice were defined including the full spectrum of multidisciplinary aspects of care. RESULTS: 19 criteria for best practice were defined including recommendations on surgical training, intraoperative transoesophageal echocardiography, surgery for atrial fibrillation, audit, and cardiology and imaging issues. CONCLUSIONS: Standards for best practice in mitral valve repair were defined by multidisciplinary consensus. This study gives centres undertaking mitral valve repair an opportunity to benchmark their care against agreed standards that are challenging but achievable. Working towards these standards should act as a stimulus towards improvements in care.

Atrial Fibrillation↗
PubMed2004

Thermoluminescence dosimetry in mixed neutron/gamma radiation beam.

Miniature CaF2:Tm (TLD-300) were adopted for dosimetry in a mixed neutron/gamma beam produced by the Detroit superconducting cyclotron. A method utilizing the linear relationship between the ratios of the areas under the low and high temperature peaks of the glow curve and the ratios of gamma dose to total dose (Dgamma/DT) in d(48.5)+Be fast-neutron beam was applied for both the gamma component and the total dose measurements. The detectors were grouped based on their response to uniform 60Co dose. Within each group the ratio of the peak areas of the glow curve demonstrated uniformity and stability better than 1.5% (one standard deviation). The parameters of the linear regression between the fractional gamma component in the neutron beam and the ratio of peak areas were derived from measurements at locations with predetermined Dgamma/DT. The method was applied to measure the transmission through the existing multi-rod and newly designed multi-leaf collimators.

Body Burden↗
PubMed2004

Platelet storage solution affects on the accuracy of laboratory tests for platelet function: a multi-laboratory study.

BACKGROUND AND OBJECTIVES: Extent of shape change (ESC) and hypotonic shock response (HSR) have been widely used to characterize the in vitro function of platelets and have been shown to correlate with in vivo viability. These assays have been routinely performed using platelet-poor plasma (PPP) as the test sample diluent. Because of the increasing popularity of storing platelets in synthetic media, it is important to understand the effects of using these synthetic media as test diluents for ESC and HSR measurements. The objective of this study was to determine the effect of using platelet storage solutions vs. plasma for the in vitro testing of ESC and HSR. MATERIALS AND METHODS: Six laboratories participated in this study. Platelets were prepared by apheresis, the platelet-rich plasma (PRP) method, or derived from buffy-coats. Each platelet preparation was divided, half being stored in plasma and the other half in storage solution. ESC and HSR testing were performed in duplicate on days 1 and 5, using each of three diluents: autologous plasma; fresh-frozen plasma; or storage solution. RESULTS: For both ESC and HSR, dilutions made in each of the three diluents yielded significantly different results. Dilutions made in storage solutions were more than 30% lower for ESC and HSR than those made in autologous plasma (P < 0.0001). Dilutions made in thawed fresh-frozen plasma were more than 16% lower for ESC and HSR than those made in liquid autologous plasma (P < 0.0005). CONCLUSIONS: ESC and HSR test results are significantly affected by the test diluent. Platelets should be diluted in plasma (preferably autologous) for the in vitro testing of ESC and HSR, regardless of the media in which they are stored.

Blood Platelets↗
PubMed2003

Nutrient removal from wastewaters using high performance materials.

Return side streams from anaerobic digesters and dewatering facilities at wastewater treatment plants (WWTPs) contribute a significant proportion of the total nitrogen load on a mainstream process. Similarly, significant phosphate loads are also recirculated in biological nutrient removal (BNR) wastewater treatment plants. Ion exchange using a new material, known by the name MesoLite, shows strong potential for the removal of ammonia from these side streams and an opportunity to concurrently reduce phosphate levels. A pilot plant was designed and operated for several months on an ammonia rich centrate from a dewatering centrifuge at the Oxley Creek WWTP, Brisbane, Australia. The system operated with a detention time in the order of one hour and was operated for between 12 and 24 hours prior to regeneration with a sodium rich solution. The same pilot plant was used to demonstrate removal of phosphate from an abattoir wastewater stream at similar flow rates. Using MesoLite materials, >90% reduction of ammonia was achieved in the centrate side stream. A full-scale process would reduce the total nitrogen load at the Oxley Creek WWTP by at least 18%. This reduction in nitrogen load consequently improves the TKN/COD ratio of the influent and enhances the nitrogen removal performance of the biological nutrient removal process.

Aluminum Silicates↗
PubMed2001

Characterization and cloning of a major high molecular weight house dust mite allergen (Der f 15) for dogs.

Although house dust mites (HDM(s)) are important elicitors of canine allergy, the low molecular weight molecules defined as major allergens for humans do not appear to be major allergens for dogs. Western blotting of Dermatophagoides farinae (D. farinae) extracts with sera from sensitized dogs showed that the majority of animals had IgE antibodies specific for two proteins of apparent molecular weights of 98 and 109kDa (98/109kDa). The N-terminal sequences of these two proteins were identical, suggesting they were very closely related, and sequencing of internal peptides showed the protein(s) to have homology with insect chitinases. A purified preparation of 98/109kDa proteins elicited positive intradermal skin tests (IDST(s)) in a group of well-characterized atopic dogs sensitized to D. farinae, but not in normal dogs. A rabbit polyclonal antiserum raised against the purified proteins was used to immunoscreen a D. farinae cDNA library. The mature coding region of the isolated chitinase cDNA predicts a protein of 63.2kDa; sequence analysis and glycan detection blotting suggest that the molecule is extensively O-glycosylated. Monoclonal antibodies made against the purified native protein were used to localize the chitinase in sections of whole D. farinae mites. The protein displayed an intracellular distribution in the proventriculus and intestine of the mite, suggesting that it has a digestive, rather than a moulting-related, function. The high prevalence of IgE antibodies to this antigen in canine atopic dermatitis makes it a major HDM allergen for dogs, and the protein has been formally designated Der f 15.

Amino Acid Sequence↗
PubMed2001

Measurement of canine IgE using the alpha chain of the human high affinity IgE receptor.

In vitro assays for allergen specific immunoglobulin E (IgE) are a convenient and reproducible alternative to intradermal skin testing in dogs. Such tests may be used to support a diagnosis of atopic dermatitis and to define appropriate allergens for immunotherapy. Current in vitro assays rely upon monoclonal or polyclonal antibodies as IgE detection reagents. However, in sera where allergen-specific IgG occurs in great excess, any IgE:IgG cross-reactivity of the detection reagent may result in lowered assay specificity. Therefore, we have developed an assay for canine IgE which uses a recombinant form of the extracellular part of the alpha chain of the human high affinity IgE receptor (FcvarepsilonRIalpha). Biotinylated FcvarepsilonRIalpha shows no significant binding to purified canine IgG, and recognizes a heat labile antibody in serum, with a detection limit of 73-146pg/ml. Comparison of assay signals using the labeled FcvarepsilonRIalpha and a highly specific anti-canine IgE monoclonal antibody (MAb) shows good agreement. The FcvarepsilonRIalpha is therefore a sensitive and specific alternative to polyclonal or monoclonal antibodies for canine serum IgE measurement.

Animals↗
PubMed2001

Fc gamma receptors differ in their structural requirements for interaction with the tyrosine kinase Syk in the initial steps of signaling for phagocytosis.

Receptors for the constant region of IgG, Fc gamma receptors, are expressed on the surface of hematopoietic cells, where they mediate signaling events, such as phagocytosis, essential for host defense. Fc gamma receptors also play a role in the pathophysiology of autoimmune diseases. We have demonstrated that members of each of the three classes of human Fc gamma receptors, Fc gamma RI, Fc gamma RII, and Fc gamma RIII, mediate phagocytosis, but that important differences exist in their requirements for phagocytic signaling. For example, the Fc gamma receptors Fc gamma RI and Fc gamma RIIIA induce signaling largely by association with a gamma subunit containing a conserved cytoplasmic motif (ITAM) whose tyrosines are phosphorylated following receptor stimulation. Fc gamma RIIA contains a similar motif in its own cytoplasmic domain and does not require the gamma chain for phagocytic signaling. The tyrosine kinase Syk associates with the cytoplasmic domain of both the Fc gamma receptor gamma chain and Fc gamma RIIA and is required for phagocytosis by both Fc gamma receptor systems. To elucidate the differences in phagocytic signaling by the gamma chain and Fc gamma RIIA, we investigated the requirements for Fc gamma receptor/Syk co-immunoprecipitation, tyrosine phosphorylation, and phagocytosis. Both Fc gamma RIIA and the human gamma chain contain a tyrosine seven amino acids upstream of the ITAM motif. We observed that the upstream tyrosine plays a role in Fc gamma RIIA phagocytic signaling but is not involved in phagocytic signaling by the human gamma chain. Our data also indicate that the two ITAM tyrosines of the human gamma chain and Fc gamma RIIA do not contribute equally to Fc gamma receptor association with Syk kinase and phagocytic signaling. The data indicate that the carboxy-terminal tyrosine of the receptor cytoplasmic domain is especially important both for the interaction with Syk kinase and for phagocytosis. Elucidating such differences in gamma chain and Fc gamma RIIA signaling may be valuable in designing strategies for therapeutic intervention in hematopoietic and immunological disorders.

Animals↗
PubMed2001

The effect of the interruption of agitation on platelet quality during storage for transfusion.

BACKGROUND: A considerable amount of data and the CFR suggest that platelet concentrates (PCs) should be stored with continuous, gentle agitation before transfusion. However, there are only limited data concerning the mechanisms of platelet damage that may occur when agitation is interrupted, and there are no CFR guidelines concerning shipment between periods of storage. STUDY DESIGN AND METHODS: PCs were prepared by the platelet-rich plasma method and stored for 5 days at 20 to 24 degrees C; agitation was interrupted for 1 to 3 days either by simply stopping the agitator or by placing the PCs in a stationary shipping container. Measurements of platelet metabolism and quality were made during storage and on Day 5. RESULTS: With interruption on the agitator, the production of lactic acid was increased during the interruption in proportion to the number of platelets in the PC and the duration of the interruption. The pO(2) was increased during agitation interruption, which suggested a decline in oxygen utilization. With the use of the hypotonic shock response and the extent of shape change as reflections of platelet quality, there was no evidence of platelet damage unless the pH fell to or below 6.5. No PC reached this level after an interruption of agitation for only 1 day, irrespective of which day was chosen for interruption. PCs whose agitation was interrupted for 2 and 3 days were at risk of having a pH less than 6.5 if their contents were greater than 1.25 x 10(11) and 0.75 x 10(11) platelets, respectively. Interruption of agitation for 1 day in the shipping container produced results essentially identical to those produced by interruption on the agitator. CONCLUSION: Interruption of agitation of PCs for 1 day, either on the agitator or in the shipping container, produces no platelet damage measurable by these in vitro techniques. However, an interruption of agitation for 2 days can result in significant damage in some components. Further studies will be required to learn more about the mechanisms that lead to the metabolic changes described and to determine if the same generalizations apply to apheresis PCs and PCs prepared from pooled buffy coats.

Blood Platelets↗
PubMed2001

Invasive M-type 3 Streptococcus pyogenes affecting a family and a residential home.

This paper describes the first recognised United Kingdom outbreak of M-type 3 streptococci for 12 years. Four epidemiologically-linked invasive infections occurred in a residential home in northern England over two weeks. The index patient was admitted from home with necrotising fasciitis of the leg. Infection was subsequently detected in her husband (fatal pneumonia) another resident (fatal pneumonia) and a member of the care staff (parapharyngeal abscess). Screening of staff and residents in the home did not reveal any further infection or carriage. There is a substantial risk of serious secondary infection amongst the contacts of a patient with invasive Streptococcus pyogenes infection. Guidance is lacking, but needed, on the advisability of chemoprophylaxis in these circumstances.

Adult↗
PubMed2000

An intervention study on screening for breast cancer among single african-american women aged 65 and older.

PURPOSE: Older single African-American women are the population that is least likely to use screening procedures because of cognition-related, income-related, social-support-related and medical care-related barriers. This study aims to evaluate a breast screening intervention program developed according to socioeconomic, cultural, psychological and behavioral characteristics of older single African-American women.METHODS: Ten public housing complexes were randomly assigned to either intervention or control group. African-American women aged 65 and over were recruited into the study if they were widowed, divorced, separated or never-married in the preceding year, and did not have a history of breast cancer (n = 325). Delivered by lay health educators, the intervention program targeted increasing knowledge on breast health and breast screening, reducing emotional or psychological problems, and increasing support from the significant others of study women. Breast screening-related cognition and behavior were measured at pre-intervention and post-intervention.RESULTS: Comparisons of the pre-intervention and post-intervention measurements showed that while the proportion of women who had a clinical breast examination or mammogram in the preceding year was decreased at the post-intervention in the control group, it was increased in the intervention group. However, the differences did not reach a significant level. No consistent patterns could be found in changes of variables in knowledge, attitudes and beliefs. These results remained similar when potential confounding factors were adjusted using mixed model regression analyses.CONCLUSIONS: These results did not suggest significant effects of an intervention program which used lay health educators to promote breast cancer screening in older single African-American women.

Journal Article↗
PubMed2000

Depression-related variables and breast self-examination in single older african-american women.

PURPOSE: Depression-related symptoms, such as despair and loneliness, may prevent women from using preventive screening for diseases. This study aimed to assess if depression-related variables affect the likelihood of implementation of breast self-examination (BSE) in single African-American women aged 65 and older.METHODS: Subjects for this study included 325 African-American women, aged 65 and older, who were widowed, divorced, separated, or never-married, and lived in ten public housing tenements in Nashville, Tennessee. In-person interviews were conducted to collect information on breast screening behavior, knowledge and attitudes, social networks and activities, medical care use and depression. Depression variables included 19 factors, such as feeling guilty, feeling sad or blue, and feeling worthless.RESULTS: Using logistic regression with adjustment for potential confounders, we found that, compared with women who did not perform BSE, those who performed BSE were less likely to have felt guilty in the preceding year (p < 0.05, odds ratio (OR) = 0.3, confidence interval (CI) = 0.13-0.71). However, the other depression-related variables were not associated with BSE. For example, women who performed BSE and those who did not perform BSE reported feeling sad or blue in equal frequencies (OR = 0.93, CI 0.49-1.7).CONCLUSIONS: In general, this study suggests that there is no overall association between depression-related symptoms and breast self-examination in single African-American women aged 65 and older.

Journal Article↗
PubMed2000

Identification, cloning, and characterization of a major cat flea salivary allergen (Cte f 1).

An 18 kDa protein isolated from saliva of the cat flea, Ctenocephalides felis, elicits a positive intradermal skin test (IDST) in 100 and 80% of experimental and clinical flea allergic dogs, respectively. Using solid-phase enzyme-linked immuno assay (ELISA), this protein detected IgE in 100 and 80% of experimental and clinical flea allergic dogs, respectively. A cDNA (pFSI) encoding a full-length Cte f 1 protein was isolated from a C. felis salivary gland cDNA library, using a combination of PCR and hybridization screening. This cDNA is 658 bp in length, and contains an open reading frame of 528 bp. The open reading frame encodes a protein of 176 amino acids, consisting of an 18 amino acid signal sequence and a 158 amino acid mature protein. The calculated molecular weight and pI of the mature protein are 18106 Da and 9.3, respectively. The protein, named Cte f 1, is the first novel major allergen described for canine flea allergy. Recombinant Cte f 1 (rCte f 1) was expressed in Escherichia coli, Pichia pastoris and baculovirus infected Trichoplusia ni cells. Approximately, 90% of the rCte f 1 expressed in E. coli accumulated in insoluble inclusion bodies, which could be refolded to a soluble mixture of disulfide isomers with partial IgE binding activity. Small quantities of an apparently correctly refolded form of rCte f 1, which had IgE binding activity equal to the native antigen, was isolated from the soluble fraction of E. coli cells. However, P. pastoris and baculovirus infected insect cells expressed and secreted a fully processed, correctly refolded and fully active form of rCte f 1. Mass spectrometry analysis of the active forms of rCte f 1confirmed that eight intact disulfide bonds were present, matching the number observed in the native allergen. The relative ability of rCte f 1 to bind IgE in the serum of flea allergic animals, produced in these three expression systems, matched that of the native allergen. Competition ELISA demonstrated that approximately 90% of the specific IgE binding to native Cte f 1 could be blocked by the different forms of rCte f 1.

Alkylation↗
PubMed2000

Fetal diagnosis of lethal dysfunction of the right heart in three siblings.

A woman, having already delivered one child, underwent fetal echocardiography during three subsequent pregnancies. All three showed enlargement and poor function of the right-sided chambers. The first was still-born, the second died as a neonate, while the third pregnancy was terminated. Pathological examination revealed the same findings in each fetus, possibly representing a variation of Uhl's anomaly, or alternatively a hitherto unrecognised cardiomyopathic process.

Adult↗
PubMed2000

Prenatal diagnosis of congenital heart disease in the northern region of England: benefits of a training programme for obstetric ultrasonographers.

OBJECTIVE: To examine the results of fetal cardiac scanning and audit the changes in performance resulting from the introduction of a training programme for obstetric ultrasonographers. METHODS: Using the database of the Northern Regional Congenital Abnormality Survey (NORCAS), fetuses with complex or significant congenital heart disease (CCHD) diagnosed prenatally in 1994 were identified. A simple programme of centralised and local training was instituted in 1995 by the department of paediatric cardiology to teach obstetric ultrasonographers in district general hospital maternity departments to identify congenital heart malformations. The results of the training programme were assessed by comparing the 1994 identification rate of CCHD with the rates for 1996 and 1997. RESULTS: Birth rate fell during the study from 35,026 in 1994 to 32,874 in 1997. Registration of CCHD also fell, from 115 in 1994 to 87 in 1997. Prenatal recognition of CCHD rose from 17% in 1994 to 30% in 1995 and 36% in 1996. In 1997 it fell slightly to 26.9%. The total number of scans did not change much year on year, but the number of parents choosing termination increased significantly (from 22.7% to 57%). CONCLUSIONS: A simple training programme for obstetric ultrasonographers increased their ability to detect serious congenital heart disease at a routine 18-20 week anomaly scan. With a termination rate of more than 50%, the incidence of CCHD in the population fell from 3.3/1000 to 2.6/1000 live births. This audit, conducted within a stable population using ascertainment by a well established fetal malformation registry, suggests that prenatal diagnosis may have a significant effect on the incidence of complex or serious congenital cardiac malformations.

Abortion, Therapeutic↗
PubMed2000

Determination of moral negligence in the context of the undermedication of pain by nurses.

The problem of undermedication of pain in health care is widely recognized and acknowledged; however, there is an obvious lack of exploration of this problem from an ethical perspective. When undermedication is raised as a moral concern, the underlying premise is that a patient may experience harm or not benefit from ineffective pain management practices. I will argue that the harm is of a particular type, that is, moral negligence. My intention is to increase nurses' awareness of both the type of moral harm they are causing, and their professional and moral duties to provide appropriate medication, more particularly to avoid undermedication. I hope that this heightened awareness will be incorporated into practice. As a nurse, I chose to focus on nursing for this article, but my claims are applicable to other health professions, such as medicine.

Analgesics↗