Multiple Magnetic Bilayers and Unconventional Criticality without Frustration in BaCuSi_{2}O_{6}.

The dimerized quantum magnet BaCuSi_{2}O_{6} was proposed as an example of "dimensional reduction" arising near the magnetic-field-induced quantum critical point (QCP) due to perfect geometrical frustration of its interbilayer interactions. We demonstrate by high-resolution neutron spectroscopy experiments that the effective intrabilayer interactions are ferromagnetic, thereby excluding frustration. We explain the apparent dimensional reduction by establishing the presence of three magnetically inequivalent bilayers, with ratios 3∶2∶1, whose differing interaction parameters create an extra field-temperature scaling regime near the QCP with a nontrivial but nonuniversal exponent. We demonstrate by detailed quantum Monte Carlo simulations that the magnetic interaction parameters we deduce can account for all the measured properties of BaCuSi_{2}O_{6}, opening the way to a quantitative understanding of nonuniversal scaling in any modulated layered system.

Magnetic Field Dependence of Excitations Near Spin-Orbital Quantum Criticality.

The spinel FeSc_{2}S_{4} has been proposed to realize a near-critical spin-orbital singlet (SOS) state, where entangled spin and orbital moments fluctuate in a global singlet state on the verge of spin and orbital order. Here we report powder inelastic neutron scattering measurements that observe the full bandwidth of magnetic excitations and we find that spin-orbital triplon excitations of an SOS state can capture well key aspects of the spectrum in both zero and applied magnetic fields up to 8.5 T. The observed shift of low-energy spectral weight to higher energies upon increasing applied field is naturally explained by the entangled spin-orbital character of the magnetic states, a behavior that is in strong contrast to spin-only singlet ground state systems, where the spin gap decreases upon increasing applied field.

Noncoplanar and counterrotating incommensurate magnetic order stabilized by Kitaev interactions in γ-Li(2)IrO(3).

Materials that realize Kitaev spin models with bond-dependent anisotropic interactions have long been searched for, as the resulting frustration effects are predicted to stabilize novel forms of magnetic order or quantum spin liquids. Here, we explore the magnetism of γ-Li(2)IrO(3), which has the topology of a three-dimensional Kitaev lattice of interconnected Ir honeycombs. Using magnetic resonant x-ray diffraction, we find a complex, yet highly symmetric incommensurate magnetic structure with noncoplanar and counterrotating Ir moments. We propose a minimal Kitaev-Heisenberg Hamiltonian that naturally accounts for all key features of the observed magnetic structure. Our results provide strong evidence that γ-Li(2)IrO(3) realizes a spin Hamiltonian with dominant Kitaev interactions.

One-year survey of carcinoma of the oesophagus and stomach in Wales.

BACKGROUND: The aim of the study was to identify all patients who presented with oesophagogastric malignancy within a single National Health Service region (Wales) over 1 year, and to follow the cohort for 5 years. Management and outcome were analysed to identify current practice and draft guidelines for Wales. METHODS: Patients were identified from hospital records. Details were recorded in structured format for analysis. RESULTS: Analysable data were obtained for 910 of 916 patients. The overall incidence was 31.4 per 100 000 population. Treatment was by resection 298 (33 per cent), palliation 397 (44 per cent) or no treatment 215 (24 per cent). The 30-day mortality rate was 12 per cent and the in-hospital mortality rate was 13 per cent. Some 226 patients (25 per cent) were alive at 2 years. Resection conferred a significant survival advantage over palliation (P < 0.001) and no treatment. Anastomotic leakage occurred in 16 patients (5 per cent), of whom eight died in hospital. 'Open and close' operations were common (23 per cent), laparoscopy was infrequent (16 per cent), and many surgeons undertook small caseloads. Operating on fewer than six patients per year increased the mortality rate after partial gastrectomy (P < 0.05) and was associated with a trend to a higher mortality rate after mediastinal and cardia surgery. Operating on more than 70 per cent of patients seen resulted in a significantly higher mortality rate (P < 0.01) irrespective of case volume. CONCLUSION: Tumour resection conferred a survival advantage. Wider use of laparoscopy is advocated. Improved selection for surgery should result in a lower mortality rate.

Oesophageal and gastric cancer pathology reporting: a regional audit.

AIM: To audit the information content of pathology reports of oesophageal and gastric cancer resection specimens in Wales. METHODS: All such reports from the 16 NHS histopathology laboratories in Wales in a one year period were evaluated for their information content. Two standards were used: (1) best practice reporting, and (2) a minimum dataset required for informed patient management that included clear statements on histological tumour type, depth of tumour invasion, lymph node involvement, and completeness of excision. RESULTS: 282 reports were audited. Minimum standards were achieved in 77% of gastric resections (156/203) and 53% of oesophageal resections (42/79). All laboratories achieved minimum standards in some gastric cancer reports (range 50-100%); three laboratories did not achieve minimum standards in any oesophageal cancer reports (range 0-100%). Best practice reporting was achieved in only 20% of gastric and 18% of oesophageal cancer reports. Failure to include an explicit statement on completeness of excision or involvement of the oesophageal circumferential resection margin were the most frequent causes of inadequate reporting. Most other data items were generally well reported, but apparent inadvertent omission of just one item was noted in many of the substandard reports. CONCLUSIONS: This audit shows the need to improve the information content of pathology reports in gastric and oesophageal cancer. The widespread implementation of template proforma reporting is proposed as the most effective way of achieving this. Multidisciplinary meetings of clinicians involved in cancer management should provide a forum for greater communication between pathologists and surgeons, and help to maintain standards of pathological practice.

Mortality from ruptured abdominal aortic aneurysm in Wales.

BACKGROUND: The aim of this study was to identify the incidence of, and mortality in, patients with a ruptured abdominal aortic aneurysm (AAA) reaching hospital alive in Wales. METHODS: Patients who presented with a ruptured AAA between September 1996 and August 1997 were analysed. Data were collected prospectively by an independent body, observing strict confidentiality. RESULTS: Some 233 patients with a confirmed ruptured AAA were identified, giving an incidence of eight per 100 000 total population. Some 133 patients (57 per cent) underwent attempted operative repair; 85 (64 per cent) of these died within 30 days. Of the 233 patients, 92 were admitted under the care of a vascular surgeon and 141 under a non-vascular surgeon. Vascular surgeons operated on 82 patients (89 per cent), of whom 50 (61 per cent) died, whereas non-vascular surgeons operated on 51 patients (36 per cent), of whom 35 (69 per cent) died. DISCUSSION: This study is unique as it is an independent prospective study of mortality in patients with a ruptured AAA who reached hospital alive. Mortality was independent of the operating surgeon, but vascular surgeons turned down significantly fewer patients than non-vascular surgeons (11 versus 64 per cent, P < 0.001).

Vascular surgical society of great britain and ireland: deaths from ruptured abdominal aortic aneurysm in wales

BACKGROUND: The aim was to determine the true incidence and operative mortality rate of patients with ruptured abdominal aortic aneurysm (AAA) who reach hospital alive in Wales. METHODS: Patients presenting with a ruptured AAA between September 1996 and August 1997 were analysed. The data were collected prospectively by an independent body, observing strict confidentiality. RESULTS: Two hundred and thirty-three patients with confirmed ruptured AAA were identified. One hundred and thirty-three patients (57 per cent) underwent attempted operative repair. Eighty-five (64 per cent) died within 30 days. All 100 patients who received no operation died. Of the 233 patients, 92 were admitted under vascular surgeons (VSs) and 141 under non-vascular surgeons (NVSs). VSs operated on 82 patients (89 per cent) of whom 50 (61 per cent) died; NVSs operated on 51 (36 per cent) of whom 35 (69 per cent) died. CONCLUSION: This study is the only independent prospective study of death among patients with ruptured AAA who reached hospital alive. Some 57 per cent of the patients with a ruptured AAA were operated on. The operative mortality rate was 64 per cent and the overall mortality rate was 79 per cent. VSs were significantly more aggressive (89 per cent) in the management of ruptured AAA (i.e. more likely to operate) than NVSs (36 per cent) (P < 0.0001). Despite this, the operative mortality rate for VSs was 61 per cent, whereas for NVSs it was 69 per cent (P = 0.372). The overall mortality rate (including operated and non-operated patients) for NVSs (89 per cent) was significantly higher than that for VSs (65 per cent) (P < 0.0001). In Conclusion:, ruptured AAA is common in Wales and associated with a high mortality rate even when managed by VSs.

Surgeons' follow-up practice after resection of colorectal cancer.

Consultant surgeons in two United Kingdom Health Regions were invited to complete a questionnaire on details of their personal management of patients with colon and rectal cancer, with particular emphasis on follow-up. Replies from 140 (94%) were analysed by the surgeon's subspecialty of colorectal and gastrointestinal surgery (group 1) and all others (group 2). There was a wide variation in the duration of followup, but no difference between the two groups. More group 1 surgeons carried out investigations as a routine after colonic (P < 0.01) and rectal (P < 0.01) resection. Colonoscopy was used more frequently by group 1 (P < 0.0001) and barium enema by group 2 surgeons (P < 0.05). Investigations to detect asymptomatic metastases were used as a routine by 33.3% of surgeons, in whom there was no concordance over the choice or combination of tests and no difference between the two groups of surgeons. There is no consensus among surgeons as to the ideal duration, intensity and method of follow-up after resection for colorectal cancer and little difference between the practice of colorectal and gastrointestinal surgeons and that of other specialists, except in the use of colonoscopy and barium enema. These results reflect the continuing lack of evidence on which to base the follow-up of patients after surgery for colorectal cancer.

Colorectal cancer pathology reporting: a regional audit.

AIMS: To audit the information content of pathology reports of colorectal cancer specimens in one National Health Service region. METHODS: All reports of colorectal cancer resection specimens from the 17 NHS histopathology laboratories in Wales during 1993 were evaluated against: (a) standards previously agreed as desirable by pathologists in Wales; and (b) standards considered to be the minimum required for informed patient management. RESULTS: 1242 reports were audited. There was notable variation in the performance of different laboratories and in the completeness of reporting of individual items of information. While many items were generally well reported, only 51.5% (640/ 1242) of rectal cancer reports contained a statement on the completeness of excision at the circumferential resection margin and only 30% (373/1242) of all reports stated the number of involved lymph nodes. All of the previously agreed items were contained in only 11.3% (140/1242) of reports on colonic tumours and 4.0% (40/1242) of reports on rectal tumours. Seventy eight per cent (969/1242) of colonic carcinoma reports and 46.6% (579/ 1242) of rectal carcinoma reports met the minimum standards. CONCLUSIONS: The informational content of many routine pathology reports on colorectal cancer resection specimens is inadequate for quality patient management, for ensuring a clinically effective cancer service through audit, and for cancer registration. Template proforma reporting using nationally agreed standards is recommended as a remedy for this, along with improved education, review of laboratory practices in the light of current knowledge, and further motivation of pathologists through their involvement in multidisciplinary cancer management teams.

Population-based audit of colorectal cancer management in two UK health regions. Colorectal Cancer Working Group, Royal College of Surgeons of England Clinical Epidemiology and Audit Unit.

BACKGROUND: To obtain information on the contemporary management of colorectal cancer in the UK to assist in the development of management guidelines, an independent, 1-year population audit was carried out in Trent Region and Wales. METHODS: Data were collected on all patients admitted to hospital with a new diagnosis of colorectal cancer in a 1-year period. RESULTS: Of 3520 patients, 3221 (91.5 per cent) had surgery. Emergency/urgent operations were carried out as the first procedure in 552 (17.1 per cent). Resection of the primary disease was achieved in 2859 (81.2 per cent) and this was deemed curative in 2070 (58.8 per cent). Twenty-one per cent of all patients had metastatic disease at presentation. Overall, 30-day operative mortality was 7.6 per cent (21.7 per cent for emergency/urgent and 5.5 per cent for scheduled/elective procedures). Anastomotic dehiscence occurred in 105 patients (4.9 per cent); this was 3.9 per cent after colonic resections and 7.9 per cent after anterior rectal resections. Elective rectal excision resulted in a permanent stoma in 486 of 1054 patients (46 per cent). CONCLUSION: This initial report from a comprehensive, independent audit of colorectal cancer management shows improvement in some aspects of treatment as evidenced by improved anastomotic dehiscence and stoma rates when compared with previous studies. However, there has been little improvement in the proportion of patients presenting with advanced disease, and curative resection rates remain low.

Control of hydatid disease in Wales.

OBJECTIVES: To evaluate the success of the south Powys hydatid control programme by analysis of trends in cystic disease in humans and sheep and dog infestation. DESIGN: A review of hospital admissions for human hydatid disease in 1984-90, abattoir prevalence surveys of hydatid cysts in adult sheep, arecoline acetarsol and coproantigen surveys of prevalence of Echinococcus infestation in dogs. SETTING: All hospitals in England and Wales, three abattoirs, and dog populations in mid ands south east Wales. SUBJECTS: Residents of England and Wales admitted to hospital between 1984 and 1990 with a new diagnosis of human hydatid disease (International Classification of Diseases (ICD), ninth revision, code 122) acquired in the United Kingdom. RESULTS: The average annual incidence of human hydatid disease in Powys, mid-Wales, fell from 3.9x10(-5) in 1974-83 to 2.3x10(-5) in 1984-90. Age specific incidence rates in Wales declined over this period only in children, and no cases occurred in children (<15 years) in Powys. Two Welsh children who lived in Gwent and mid-Glamorgan were infected. Prevalence of hydatid cysts in old sheep from south Wales declined during the control period, but in 1993 prevalence of cysts was 13%. Prevalence of E granulosus infestation was zero in the control area in 1993, but it was 2.4% in Powys dogs outside the control area in 1989 and 9.2% in dogs in Gwent in 1991. CONCLUSIONS: Human hydatid disease has been successfully controlled in south Powys but cystic echinococcosis is still endemic in sheep in mid-Wales, and there is a focus of infection in humans, sheep, and dogs in the bordering areas of Gwent and mid-Glamorgan. There is considerable potential for an upsurge in human cases if control measures are relaxed.

Human hydatid disease: evaluation of an ELISA for diagnosis, population screening and monitoring of control programmes.

The routine use of ELISA and complement fixation tests in the diagnosis of suspected clinical cases of hydatid disease was evaluated. In the ELISA test, dialysed and filtered sheep cyst fluid was used as antigen and two positive cut-off points--+3SD and +2SD of the mean absorbance values of the control sera--were evaluated. The predictive values of ELISA tests were 82% and 90% for positive tests, and 86% and 82% for negative tests, respectively with the two cut-off points. In a population survey of blood donors and veterinary workers in Powys, 4% and 8%, respectively, had ELISA values above the lower cut-off point. However, it would not be appropriate to use the same test for diagnostic population screening in Wales since the predictive value of the test is likely to be very low in this setting. Serological surveys with the ELISA may be of use in monitoring the progress of the South Powys Hydatid Control Programme. The use of cumulative percentages was found to be a useful method of comparing whole distributions of results in different populations.

Outcome of neonatal necrotising enterocolitis: results of the BAPM/CDSC surveillance study, 1981-84.

Neonatologists in 100 special care baby units in the United Kingdom and Ireland collaborated in a four year surveillance study of neonatal necrotising enterocolitis. The average overall annual reporting rate of necrotising enterocolitis for infants in England and Wales was 0.3/1000 live births, but ranged from 9.5/1000 live births in infants weighing less than 1000 g at birth to 0.2/1000 live births in infants weighing 2500 g or more. There were more deaths among girls, infants who weighed less than 1500 g at birth, those whose bleeding was abnormal or who had low peripheral platelet counts, infants with Gram negative bacteraemia, and very low birthweight infants who developed it during the first few days of life. In both boys and girls, and in all birthweight groups, operation was associated with increased mortality.

The changing incidence of human hydatid disease in England and Wales.

The incidence of hospital-diagnosed human hydatid disease acquired in the UK was estimated from a survey based on Hospital Activity Analysis data for the period 1974-83. The average annual incidence in Wales was 0.4 per 100,000 population compared with 0.02 per 100,000 in England. Within Wales, Powys, and particularly Brecknock, had the highest incidence (7 per 100,000 per year). Compared with the period 1953-62, the average annual incidence for Wales fell by half (from 0.8 to 0.4 per 100,000 per year), but in Powys the incidence did not decline, and in Brecknock and Montgomery there was a marginal increase. In comparison with 1953-62, the age-specific incidence in Wales and Powys decreased in each age group with the notable exception of children less than 15 years of age. This finding emphasizes that transmission of Echinococcus granulosus to humans is still occurring at hyper-endemic levels in parts of England and Wales and that control efforts should be intensified.

Micro-aggregate content of red cell suspensions stored in saline adenine glucose mannitol optimal additive solution.

The micro-aggregate content of blood collected into conventional CPDA-1 preservative was compared with that of red cells stored in saline adenine glucose and mannitol optimal additive preservative solution (SAG-M). The results show that the optimal additive packs from which either platelet rich or platelet poor plasma have been removed contain 38% of the micro-aggregates in CPDA-1 blood. When platelets, plasma and the buffy coat are also removed, the residual micro-aggregates amount to only 16% of those in CPDA-1 whole blood. No differences were seen between the amount of haemolysis in any of the red cell preparations. From these results and previously published guidelines for the use of micro-aggregate filters with whole blood (International Forum 1977) it may be concluded that there is no place for the routine use of micro-aggregate filters with optimal additive preserved blood unless over 12 units are likely to be transfused.

The importance of cross-match/transfusion ratio and intervals between successive cross-matches in determining red cell outdate rates.

Measurements have been made of cross-match/transfusion ratios (C/T ratio) and intervals between successive cross-matches on the same units of blood performed in three different major hospitals each providing a wide range of clinical services. Outdate rates were 4%, 15% and 25% respectively and were associated with C/T ratios of 1.3, 2.0 and 2.15. There were corresponding increases (means of 3.6, 4.5 and 5.0 days) in the length of time unused units of blood were left between successive cross-matches. Calculations of outdate rates from the above figures closely predicted the trend shown by observed non-use rates. It has thus been demonstrated that apparently small differences in blood bank practice can produce important variations in the efficiency of use of red cell units.