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Biomedical subjects

S Adams

Publications and source records attributed to S Adams.

At least 19 recordsLinked to original sources

Outbreak of norovirus illness associated with a swimming pool.

On 3 February 2004, the Vermont Department of Health received reports of acute gastroenteritis in persons who had recently visited a swimming facility. A retrospective cohort study was conducted among persons attending the facility between 30 January and 2 February. Fifty-three of 189 (28%) persons interviewed developed vomiting or diarrhoea within 72 h after visiting the facility. Five specimens tested positive for norovirus and three specimen sequences were identical. Entering the smaller of the two pools at the facility was significantly associated with illness (RR 5.67, 95% CI 1.5-22.0, P=0.012). The investigation identified several maintenance system failures: chlorine equipment failure, poorly trained operators, inadequate maintenance checks, failure to alert management, and insufficient record keeping. This study demonstrates the vulnerability of recreational water to norovirus contamination, even in the absence of any obvious vomiting or faecal accident. Our findings also suggest that norovirus is not as resistant to chlorine as previously reported in experimental studies. Appropriate regulations and enforcement, with adequate staff training, are necessary to ensure recreational water safety.

Acute Disease↗

Paediatric surgery: trends in UK surgical trainees' operative experience.

AIM: This study assesses the effects of the reconfiguration of postgraduate surgical training and changes to work patterns through legislation within UK on the operative experience of trainees completing specialty training in paediatric surgery. METHODS: Data were collected from the consolidation record of operative experience submitted by every candidate sitting the Intercollegiate Specialty Board Examination in Paediatric Surgery in UK from 1996 through 2004. A number of index procedures were chosen as surrogates of the overall operative experience and underwent detailed analysis. These comprised operations performed in the following categories: Neonatal Surgery, General Paediatric Surgery, Paediatric Urology, Paediatric Oncology, and Emergency Paediatric Surgery. RESULTS: Sixty-three sets of data comprising 12,866 operations were ultimately identified as being suitable for analysis. The average number of operations performed annually by trainees increased over the study period as did the number in each of the operative categories. The number of operations performed with senior assistance or supervision increased over this period by an average of 12.5%. This trend was also evident in emergency surgery where the average number of sample procedures performed by trainees increased by 28% over the study period. CONCLUSION: In 1995, reforms to the training grade within UK reduced the time spent in specialist training from a previously unregulated period to 72 months of higher surgical training. Subsequent directives in response to health and safety legislation have further abbreviated the length of time spent at the workplace, initially to 72 hours and more recently to 58 hours per week. This combination has been generally perceived throughout the surgical community as prejudicial to acquisition of clinical and operative competence. This study, however, fails to endorse this perception and suggests to the contrary that perhaps through increased delegation, the volume of training operations is being preserved and that operative training is now better supervised than ever before.

Clinical Competence↗

Similar endometrial development in oocyte donors treated with either high- or standard-dose GnRH antagonist compared to treatment with a GnRH agonist or in natural cycles.

BACKGROUND: This descriptive study evaluates the impact on endometrial development of standard and high doses of a GnRH antagonist in stimulated cycles compared with GnRH agonist and natural cycles. METHODS: Thirty-one oocyte donors were treated with a combination of rFSH and 0.25 mg/day ganirelix (standard dose), 2 mg/day ganirelix (high dose) or 0.6 mg/day buserelin (long protocol). Vaginal progesterone (200 mg/day) was administered in the luteal phase. Endometrial biopsies were performed 2 and 7 days after HCG administration. Additional biopsies were carried out in a subset of 12 subjects, 2 and 7 days following the LH peak of their previous natural cycle. Biopsies were evaluated histologically and by scanning electron microscopy. Gene expression profiles were also studied. RESULTS: At HCG +2, all the parameters studied were similar in all the groups and comparable to those observed in the natural cycle. At HCG +7, endometrial dating, steroid receptors and the presence of pinopodes were comparable in both GnRH antagonist groups and in the natural cycle. In buserelin group, endometrial dating and pinopode expression suggested an arrested endometrial development. For window of implantation genes, expression patterns were closer to those in the natural cycle following standard- or high-dose ganirelix than after buserelin administration. CONCLUSION: No relevant alteration was observed in the endometrial development in the early and mid-luteal phases in women undergoing controlled ovarian stimulation for oocyte donation following daily treatment with a standard- or high-dose GnRH antagonist. In addition, the endometrial development after GnRH antagonist mimics the natural endometrium more closely than after GnRH agonist.

Adolescent↗

[Contrast media kinetic in multi-slice helical CT cannot detect rectal cancer recurrence with certainty].

PURPOSE: Evaluation of different parameters of contrast media enhancement for the differentiation between scar tissue and local recurrence of rectal cancer. MATERIALS AND METHODS: We included 83 patients after operation and radiotherapy of rectal cancer. In total, 20 local recurrences were diagnosed. After administration of 75 ml Iopromide (370 mg/ml) and a delay of 65 s, the whole abdomen and pelvis were scanned in a collimation of 4 x 2.5 mm and 12.5 mm table feed per rotation. The suspected tissue was marked by the freehand ROI option in every slice and the minimum, average and maximum densities were calculated. A local recurrence was suspected if maximum density was higher than 90 HU after admission of contrast media. In addition we calculated the maximum difference of density as the difference between maximum and minimum density. RESULTS: The minimum and average densities showed no reliable differences for patients with or without local recurrence (minimum density 4 HU ( +/- 12 HU) vs. 13 HU ( +/- 21 HU), P = 0.23, average density 48 HU ( +/- 10 HU), vs. 48 HU ( +/- 17 HU)), P = 0.52. The patients suffering from local recurrence showed higher maximum densities and a higher maximum difference than the patients without recurrence (maximum density 111 HU ( +/- 13 HU) vs. 81 HU ( +/- 24 HU), P = 0.02, maximum difference 103 HU ( +/- 20 HU) vs. 76 HU ( +/- 31 HU), P = 0.06. These differences were not significant. We calculated a sensitivity of 0.6, a specificity of 0.83, a positive predictive value of 0.52 and an accuracy of 0.77. CONCLUSION: It is not possible to diagnose a recurrent rectal cancer by density values alone.

Aged↗

A genome-wide screen for linkage disequilibrium in Australian HLA-DRB1*1501 positive multiple sclerosis patients.

The association of multiple sclerosis with alleles/haplotypes from the HLA region on chromosome 6p21 is well established although the remainder of the genome remains relatively unexplored. We have completed a genome-wide screen for linkage disequilibrium in a cohort of Australian multiple sclerosis patients positive for HLA-DRB1*1501. A total of 4346 microsatellite markers provided through the "Genetic Analysis of Multiple sclerosis in EuropeanS" (GAMES) collaborative were analysed in DNA separately pooled from cases (n=217) and controls (n=187). Associations were found in four genomic regions (12q15, 16p13, 18p11 and 19q13) previously identified in linkage genome screens. Three additional regions of novel association were also identified (11q12, 11q23 and 14q21). Further analysis of these regions is required to establish whether the associations observed are due to epistatic interaction with the HLA locus.

Adult↗

Fatal donor-derived Epstein-Barr virus-associated post-transplant lymphoproliferative disorder following reduced intensity volunteer-unrelated bone marrow transplant for myelodysplastic syndrome.

Post-transplant lymphoproliferative disorders (PTLD) are a well recognised complication of conventional haemopoietic stem cell transplantation (HSCT). Reduced intensity HSCT involves intensive immunosuppression to permit engraftment. Thirty reduced intensity transplants with the FBC (fludarabine 150 mg/m2, busulphan 8 mg/m2, CAMPATH-1H 100 mg) protocol have been performed at our centre, with one confirmed EBV-positive PTLD. The female recipient developed a perforated viscus day +191 following HSCT from a volunteer unrelated male donor. A large caecal mass and a retroperitoneal abscess were excised, revealing an EBV-positive diffuse large B cell lymphoma confirmed by FISH to be of donor origin. More experience is required before the risk of PTLD in this setting can be assessed.

Epstein-Barr Virus Infections↗

CART peptides.

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Amino Acid Sequence↗

Meeting patient expectations of care: the major determinant of satisfaction with out-of-hours primary medical care?

BACKGROUND: Client or consumer expectation is considered to influence their satisfaction with the service provided, but its importance has not been quantified in health care. OBJECTIVE: The aim of this study was to determine the effect of "patient expectations of care" on satisfaction with care provided by out-of-hours services. METHODS: We surveyed 3457 patients who requested out-of-hours care from five practices, two general practice out-of-hours co-operatives and a deputizing service in an English health authority during late 1997. The independent variables were: the service providing the care (service type), where out-of-hours care was given (location of care) and whether the care met the patient's expectations. The independent variable was overall patient satisfaction with out-of-hours care. RESULTS: Patients who received the care they hoped for (their idealized expectation was met) were more satisfied than those who did not. Patients who attended centres were more satisfied with the care received than those who had had home visits. Patients were more satisfied if they received care from the co-operative which did not employ assistants than from the deputizing service. Idealized expectation (care which was hoped for) match, location of care and service type explained 34, 2 and 4% of the variance, respectively. Age, sex, ethnicity, access to a car, normative/comparative expectation (care which was expected) and whether patients expected and received telephone advice, a home visit or domiciliary care, and the delay between request for care and care provision were not independently associated with satisfaction. CONCLUSIONS: Meeting or failing to meet the care patients hoped for is an important predictor of patient satisfaction with out-of-hours care. Purchasers and providers of out-of-hours care should consider whether and how patient expectation of service can be managed. This may reduce patient dissatisfaction with the service they provide. These findings also have important implications for the design of studies which use patient satisfaction as an outcome variable.

Adult↗

Histological assessment after different methods of reperfusion following liver transplantation.

INTRODUCTION: Preservation-reperfusion injury is a major cause of graft failure after liver transplantation. This injury refers to a variety of insults after reperfusion of the graft, independent of technical errors, vascular problems, immunological reactions or infection. Significant injuries occur during the period of cold preservation. Loss of sinusoidal endothelial attachments to the underlying extracellular matrix results in loss of the normal antithrombogenic milieu. Reperfusion with recipient blood results in platelet aggregation and neutrophil sludging in all areas of denudation, preventing adequate reoxygenation. Early histopathological findings in biopsy specimens can predict poor graft outcome. OBJECTIVE: To analyse the effect of early rearterialisation on histological findings of the liver biopsies after liver transplantation. METHODS: Twenty young Large White X Landrace pigs (weight 22-28 kg) were subjected to orthotopic liver transplantation. Livers were stored in Eurocollins solution for 3 hours on ice and the animals were randomised into four different groups of increasingly early arterialisation. Groups were aligned from delayed rearterialisation (group 1) to early rearterialisation (group 4). Biopsies were taken before and after cold storage, as well as 1 hour post transplantation. RESULTS: Results show that both hepatocyte vacuolisation and neutrophil infiltration were significantly reduced in group 4 (early rearterialisation), compared with groups 1, 2 and 3. Single cell necrosis and group cell necrosis of the hepatocytes were both significantly reduced in groups 3 and 4 compared with groups 1 and 2 (early venous reperfusion). CONCLUSION: This study demonstrates that early rearterialisation is associated with a decrease in early histopathological changes in the transplanted pig liver.

Analysis of Variance↗

Reactive carbonyl formation by oxidative and non-oxidative pathways.

The spectrophotometric protein carbonyl assay is used as an indicator of protein damage by free radical reactions in vitro and in a variety of pathologies. We investigated model proteins and a variety of oxidative and non-oxidative reactions, as well as what effects hemoglobin, myoglobin, and cytochrome c might have on levels of protein carbonyls. We show that oxidative as well as non-oxidative mechanisms introduce carbonyl groups into proteins, providing a moiety for quantification with 2,4-dinitrophenylhydrazine (DNPH). Bovine serum albumin exposed to oxidative scenarios, such as hypochlorous acid, peroxynitrite, and metal-catalyzed oxidation exhibited variable, but increased levels of carbonyls. Other non-oxidative modification systems, in which proteins are incubated with various aldehydes, such as malondialdehyde, acrolein, glycolaldehyde, and glyoxal also generated significant amounts of carbonyls. Furthermore, purified myoglobin, hemoglobin, and cytochrome c show high absorbance at the same wavelengths as DNPH. The high levels observed are due to the innate absorbance of hemoglobin, myoglobin, and cytochrome c near the assay spectra of DNPH. These studies show that carbonyl content could be due to oxidative as well as non-oxidative mechanisms and that heme-containing compounds may effect carbonyl quantification.

Aldehydes↗

Radioisotope-guided surgery in patients with pheochromocytoma and recurrent medullary thyroid carcinoma: a comparison of preoperative and intraoperative tumor localization with histopathologic findings.

BACKGROUND: The objective of this study was to appraise the detection of metastases of medullary thyroid carcinoma (MTC) and pheochromocytoma using radioguided surgery (RGS) and to compare the results with external imaging modalities, surgical palpation, and histopathologic findings. METHODS: Twenty-five patients with recurrent MTC underwent preoperative scintigraphic imaging with 500 megabecquerels (MBq) of technetium 99m(V)-dimercaptosuccinic acid [(99m)Tc(V)-DMSA] and 222 MBq of indium 111 ((111)In)-pentetreotide. The radiopharmaceutical that showed the greatest preoperative tumor uptake was selected for intraoperative RGS. Surgery was performed 24 hours after the administration of (111)In-pentetreotide or 4 hours after the injection of (99m)Tc(V)-DMSA. Furthermore, three male patients underwent surgery who suffered from recurrent pheochromocytoma (injection of 180 MBq iodine 123-labeled metaiodobenzylguanidine [(123)I-MIBG] 4--5 hours before surgery). RESULTS: Overall, lesion detection sensitivities in patients with MTC for computed tomography, (111)In-pentetreotide, and (99m)Tc(V)-DMSA were 32%, 34%, and 65%, respectively. Surgical palpation identified lymph node metastases of recurrent MTC with a sensitivity of 65%, whereas RGS localized 64 malignant lesions (sensitivity, 97%). Altogether, 71 lesions could be excised, 5 of which were adjudged false positive with respect to MTC metastases. Both surgical palpation and RGS localized all paravertebral subdiaphragmatic lesions (size > or = 2 cm) of recurrent pheochromocytoma seen in the preoperative MIBG scan. CONCLUSIONS: RGS was capable of localizing more and smaller metastases of MTC compared with conventional imaging modalities and surgical palpation. However, the relatively high radioligand accumulation in the kidneys ((111)In-pentetreotide) and the dense hepatic and biliary signals using MIBG limited their use for intraoperative detection of tumors in the area of the adrenal gland.

Adult↗

Mechanisms of pH regulation in the regulated secretory pathway.

A precise pH gradient between organelles of the regulated secretory pathway is required for sorting and processing of prohormones. We studied pH regulation in live endocrine cells by targeting biotin-based pH indicators to cellular organelles expressing avidin-chimera proteins. In AtT-20 cells, we found that steady-state pH decreased from the endoplasmic reticulum (ER) (pH(ER) = 7.4 +/- 0.2, mean +/- S.D.) to Golgi (pH(G) = 6.2 +/- 0.4) to mature secretory granules (MSGs) (pH(MSG) = 5.5 +/- 0.4). Golgi and MSGs required active H(+) v-ATPases for acidification. ER, Golgi, and MSG steady-state pH values were also dependent upon the different H(+) leak rates across each membrane. However, neither steady-state pH(MSG) nor rates of passive H(+) leak were affected by Cl(-)-free solutions or valinomycin, indicating that MSG membrane potential was small and not a determinant of pH(MSG). Therefore, our data do not support earlier suggestions that organelle acidification is primarily regulated by Cl(-) conductances. Measurements of H(+) leak rates, buffer capacities, and estimates of surface areas and volumes of these organelles were applied to a mathematical model to determine the H(+) permeability (P(H+)) of each organelle membrane. We found that P(H+) decreased progressively from ER to Golgi to MSGs, and proper acidification of Golgi and MSGs required gradual decreases in P(H+) and successive increases in the active H(+) pump density.

Animals↗

Relationship between bond valence and bond softness of alkali halides and chalcogenides.

Established bond-valence parameter tables rely on the assumption that the bond-valence sum of a central atom is fully determined by interactions to atoms in its first coordination shell. In this work the influence of higher coordination shells is tested in detail for bonds between lithium and oxygen. It is demonstrated that the sum of the weak interactions with atoms of the second coordination shells significantly contributes to the valence sum and should therefore not be neglected. Since the independent refinement of the two parameters R(0) and b is hardly possible from the limited range of bond lengths occurring in the first coordination shell, the restriction of bond-valence sums to contributions from nearest neighbours implicated another far-reaching simplification: the postulation of a universally fixed value of the bond-valence parameter b which characterizes the shape of the bond-valence pseudopotential for the respective atom pair. However, recent more sophisticated applications of the bond-valence concept, e.g. to model ion-transport pathways in solid electrolytes, demand sensible estimates of the bond-valence sums for mobile ions not only at their equilibrium sites but also at interstitial sites and bottle-necks of transport pathways. Calculations of bond valences at these non-equilibrium sites require the knowledge of the actual shape of the bond-valence pseudopotential. A systematic route to a more realistic estimate of b for alkali halides and chalcogenides is developed in this work from an empirical correlation between b and the absolute softnesses of the interacting particles.

Journal Article↗

Role of the medial and lateral caudate-putamen in mediating an auditory conditional response association.

Rats with quinolinic acid lesions of the medial or lateral caudate-putamen (CPu) and controls were tested for performance of a previously learned auditory conditional response association task. The task involved the selection of two possible responses when presented with one of two different tones. Results indicated that lesions of either the medial or the lateral CPu produced a sustained deficit in the auditory conditional response association task. Only the lateral CPu lesioned rats exhibited transient motor problems immediately following surgery, but these problems did not interfere with the execution of the appropriate responses. It is suggested that both the medial and the lateral CPu are involved in response selection and response separation within egocentric space.

Animals↗