Spatiotemporal evolution of urban populations and housing: A dynamic utility-driven market-mediated model.

A model of the spatiotemporal evolution of urban areas is developed that simultaneously includes the effects on household utility of geography, population density, income distribution, and household preference for characteristics of dwellings and neighbors. The result is a utility function whose structure is similar to that of the energy of interacting spin systems in external fields. Spatiotemporal housing market evolution then results via transactions driven by increases in utility and changes in numbers of households and dwellings. It is shown that the model successfully predicts formation of monocentric and polycentric urban areas, stratification by wealth, segregation due to preferences for housing or neighbors, and the balance of supply and demand. These results go well beyond those of prior models that each dealt with subsets of these phenomena, and do so within a single, unified framework. Potential generalizations are discussed and further applications are suggested.

Up for grabs: prey herding by penguins facilitates shallow foraging by volant seabirds.

Visual and olfactory signals are commonly used by seabirds to locate prey in the horizontal domain, but foraging success depends on prey depth and the seabird's ability to access it. Facilitation by diving seabirds has long been hypothesized as a mechanism to elevate deep prey to regions more accessible to volant seabirds, but this has never been demonstrated empirically. Footage from animal-borne video loggers deployed on African penguins was analysed to establish if volant seabird encounters involved active cuing by seabirds on penguins to obtain prey and, during mutual prey encounters, if interactions were driven by the vertical displacement of prey by penguins. Independent of prey biomass estimates, we found a strong inverse relationship between penguin group size, a proxy for visibility, and the time elapsed from the start of penguins' dive bouts to their first encounter with other seabirds. Most mutual prey encounters (7 of 10) involved schooling prey elevated from depths greater than 33 m by penguins and only pursued by other seabird species once prey was herded into shallow waters. This is likely to enhance foraging efficiency in volant seabird species. As such, penguins may be integral to important processes that influence the structure and integrity of marine communities.

Foot care education in patients with diabetes at low risk of complications: a consensus statement.

AIMS: To define and agree a practical educational framework for delivery by all healthcare professionals managing patients with diabetes, particularly those at low risk of developing foot complications. METHODS: A consensus meeting of a multidisciplinary expert panel. Prior to the meeting, relevant clinical papers were disseminated to the panel for review. The consensus was largely based upon the experts' clinical experience and judgement. RESULTS: Four main health behaviours were identified for those at low risk of developing foot complications, namely: control of blood glucose levels; attendance at annual foot screening examination; reporting of any changes in foot health immediately; and the engagement in a simple daily foot care routine. CONCLUSION: There is currently little evidence-based literature to support specific foot care practices. Patients with diabetes at low risk of developing complications should be encouraged to undertake a basic foot care regimen to reduce their likelihood of developing complications.

A phase I and pharmacokinetic study of capecitabine in combination with epirubicin and cisplatin in patients with inoperable oesophago-gastric adenocarcinoma.

BACKGROUND: The purpose of this study was to evaluate the dose-limiting toxicity (DLT) and maximum tolerated dose of capecitabine when used in combination with epirubicin and cisplatin (ECC) in patients with oesophageal or gastric adenocarcinoma. Response rate, progression-free survival (PFS) and overall survival were also determined, and the effect of previous oesophago-gastric surgery or concurrent oesophago-gastric cancer on the absorption and metabolism of capecitabine was evaluated. PATIENTS AND METHODS: Patients with inoperable oesophago-gastric adenocarcinoma received up to six cycles of epirubicin (50 mg/m(2) i.v., 3-weekly), cisplatin (60 mg/m(2) i.v., 3-weekly) and capecitabine, the latter administered orally in an intermittent schedule (14 days treatment; 7-day rest period) at 3-weekly intervals. Patients were recruited into one of four escalating dose cohorts (500, 825, 1000 and 1250 mg/m(2) bd). Dose escalation occurred after six patients had completed at least one cycle of chemotherapy at the previous dose level, with DLT assessed on the toxicity of the first cycle only. Blood sampling for pharmacokinetic analyses was performed over the first 10 h of day 1 of cycle 1. RESULTS: Thirty-two patients, median age 63 years (range 32-76 years), ECOG performance status < or =2 with locally advanced (10) or metastatic (22) disease were recruited and were evaluable for toxicity. Two of five patients experienced DLT at 1250 mg/m(2) bd with grade II stomatitis (one patient) and grade III diarrhoea with febrile neutropenia (one patient). Cumulative toxicity for all cycles (n = 140) (worst grade per patient) includes grade IV oesophagitis (one patient), grade III diarrhoea (five), grade IV neutropenia with infection (seven), grade II stomatitis (four) and grade IV thrombocytopenia (one). Of 29 patients with evaluable disease, there was one complete response and six partial responses [24% response rate [95% confidence interval (CI) 10% to 44%]], a median PFS of 22 weeks (95% CI 17-27 weeks) and median overall survival of 34 weeks (95% CI 19-49 weeks). Capecitabine was rapidly absorbed after oral administration, with a t(max) of 1-2 h for capecitabine, DFCR (5'-deoxy-5-fluorocytidine) and DFUR (5'-deoxy-5-fluorouridine). The C(max) and AUC(0-)( infinity ) for capecitabine, DFCR and DFUR were similar to those observed in previous monotherapy studies of capecitabine taken after food. CONCLUSION: A dose of 1000 mg/m(2) bd of capecitabine is recommended for use on an intermittent schedule in combination with these doses and schedule of epirubicin and cisplatin. This regimen is tolerable and active in oesophago-gastric adenocarcinoma. A randomised phase III comparison with ECF is justified.

Striatal cannabinoid CB1 receptor mRNA expression is decreased in the reserpine-treated rat model of Parkinson's disease.

High levels of both endocannabinoids and endocannabinoid receptors are present in the basal ganglia. Attention has recently focused on the role of endocannabinoids in the control of movement and in movement disorders of basal ganglia origin such as Parkinson's disease. We investigated CB1 cannabinoid receptor mRNA expression in the reserpine-treated rat model of Parkinson's disease using in situ hybridization. Reserpine treatment caused a topographically organized reduction in CB1 receptor mRNA expression in the striatum (ranging from 11.6% medially to 53.6% laterally and dorsally). No change in CB1 receptor mRNA expression was observed in the cerebral cortex or septum. This reduction in CB1 receptor mRNA expression may be secondary to increased endocannabinoid stimulation of the receptor as increased basal ganglia endocannabinoid levels have been shown to occur in this model of Parkinson's disease. The data support the idea that cannabinoid receptor antagonists may provide a useful treatment for the symptoms of Parkinson's disease.

A phase II study of epirubicin, cisplatin and raltitrexed combination chemotherapy (ECT) in patients with advanced oesophageal and gastric adenocarcinoma.

BACKGROUND: The aim of this study was to evaluate the efficacy of the combination of epirubicin, cisplatin and ralitrexed (Tomudex). ECT, in patients with advanced oesophageal or gastric adenocarcinoma. Efficacy was assessed primarily as response rate and secondarily in terms of toxicity, time to progression and survival. PATIENTS AND METHODS: Twenty-one patients with histologically and/or cytologically proven unresectable (7) or metastatic (14) gastro-oesophageal adenocarcinoma, who had bi-dimensionally measurable disease, with ECOG performance status < or = 2. with adequate haematological, hepatic and renal function received first-line chemotherapy with epirubicin (50 mg/m2). cisplatin (60 mg/m2) and Tomudex (2.5 mg/m2), ECT, at three-weekly intervals. Treatment consisted of three cycles of chemotherapy, with a further three cycles if there was disease response or stabilisation. RESULTS: ECT is an active regimen in the treatment of advanced gastro-oesophageal adenocarcinoma with an overall intention-to-treat response rate of 29% (95% confidence intervals (CI): 11%-52%). In addition, 4 (19%) patients had stable disease. Median time to progression was 19 weeks (95% CI: 7-31 weeks). Median overall survival was 18 weeks (95% CI: 11-24 weeks). Seventeen patients failed to complete the six cycles of treatment due to disease progression (5). toxicity (3), non-toxic death (1 pulmonary embolism, 1 cardiac), severe allergy to epirubicin (1), patient decision (1) and five patients after the study was discontinued early due to toxicity. There were three toxic deaths: two due to sepsis complicating neutropaenia and one due to cardiorespiratory failure following drug induced enteritis. Nine patients experienced grade 3 or 4 neutropaenia, two patients experienced grade 3 or 4 nausea and vomiting and one patient had grade 4 diarrhoea. CONCLUSIONS: The combination of epirubicin, cisplatin and tomudex is active against advanced gastro-oesophageal adenocarcinoma but the toxicity suggests that further evaluation in a randomised comparison to ECF is not appropriate.

Intensive care: preparations for the Millennium. A survey of hospitals in the north of England.

In order to assess preparedness for the Millennium, we carried out a telephone survey of all Intensive Care Units in the former Northern Region. The survey disclosed wide variation in the current and planned provision of back-up power and central services, proposed staffing levels and expected demand.

Limited joint mobility in the hands and feet of adolescents with Type 1 diabetes mellitus.

AIMS: Limited joint mobility (LJM) in the foot has not been assessed in adolescents with Type 1 diabetes mellitus (DM) but is associated with neuropathic ulceration in adults. This study was designed to determine the presence of LJM in adolescents with Type 1 DM and its association with microvascular disease. METHODS: The hands, feet and hips were examined in 302 diabetic adolescents and 51 nondiabetic controls (aged 11.5-20 years). LJM was defined as less than the fifth percent reference for controls. RESULTS: Reduced motion was found in 35% of diabetic adolescents at the subtalar (ST) joint, 18% at the first metatarsophalangeal (MTP) joint, 26% at the fifth metacarpophalangeal (MCP) joint and 13% had limited passive extension of the interphalangeal (IP) joints of the hands. Limited passive IP joint extension of the hands was not present in the controls. Limited active IP joint extension, a positive 'prayer sign', occurred in 35% of diabetic adolescents and 14% of controls. Diabetic adolescents showing LJM in any of these areas, except the prayer sign, were more likely to have retinopathy (odds ratio 2.53, CI: 1.53-4.18). Those with LJM in the foot were more likely to have albumin excretion rates >7.5 microg/min (OR 2.06, CI: 1.16-3.68). CONCLUSION: LJM in the feet of adolescents with Type 1 DM is associated with microvascular disease and is a useful routine clinical measure.

The at-risk foot: the role of the primary care team in achieving St Vincent targets for reducing amputation.

Foot ulceration and ultimately amputation are major complications associated with diabetes mellitus, the occurrence of which can be substantially reduced by appropriate care. This article provides a brief overview of the problem and a simple scheme for use in primary care diabetes clinics to contribute to the reduction in this particular form of diabetes-related morbidity and mortality.

British Diabetic Association guidelines on genetic and immune screening for type 1 diabetes mellitus.

The following article is a report from the Chairman of the Professional Advisory Committee of the British Diabetic Association. The committee, with the help of a number of experts currently working in the field, produced a set of guidelines intended for use by health care professionals on the issues around genetic screening for Type 1 diabetes mellitus. The guidelines were approved by the Board of Management of the British Diabetic Association and we publish them here.

Bolus/infusional 5-fluorouracil and folinic acid. A report on two prospective, consecutive phase II studies with 5-fluorouracil dose escalation.

We have used a relatively new trial methodology, the group sequential design, to prospectively evaluate two dose levels of bolus/infusional 5-fluorouracil (5-FU) and folinic acid in 192 consecutive-patients with advanced colorectal carcinoma. On day 1, all patients received 200 mg m(-2) of folinic acid infusion over 2 h. Cohort A (n = 102 patients) received 500 mg m(-2) 5-FU by i.v. 15-min infusion followed by an infusion of 500 mg m(-2) 5-FU over 22 h. Treatment was repeated on day 2 and further cycles given 2-weekly. After sequential analysis excluded a response rate of over 40%, cohort B (n = 90 patients) received an increased dose of 600 mg m(-2) 5-FU bolus and infusion. Patients had received no prior 5-FU therapy and the two cohorts had similar demographic features. In 179 evaluable patients, the overall response rate was 18% (95% CI 12-24%) with CR of 6% and PR of 12%, with no difference between the two cohorts. Overall median survival was 34 weeks (95% CI 30-39) with no significant difference between cohorts (median survival 32 and 37 weeks in cohort A and B respectively; P = 0.27). On multivariate analysis, poor performance status, elevated initial WBC and alkaline phosphatase and low serum albumin were associated with reduced survival (P < 0.05), and initial raised WBC showed an association with reduced likelihood of response (P = 0.002). Overall toxicity was low with CTC grade 3 mucositis, diarrhoea, nausea or vomiting in < or = 6% of patients and no treatment-related deaths. Significant (grade 3 or above) leucopenia was more common in cohort B than in cohort A (9% and 1% respectively); there were more dose reductions, and the median administered dose intensity was lower in cohort B than in cohort A (89% and 97% respectively; P = 0.006). In this group of relatively unselected patients, we have confirmed a relatively low objective response rate and median survival of 7.8 months with this regimen. There was no significant difference in outcome between the two dose levels but the higher dose of 5-FU was associated with more dose reductions and greater toxicity.

Know how--diabetic foot ulceration.

Diabetes is a complex metabolic disease which can give rise to many tissue complications. The foot is particularly vulnerable to circulatory and neurological disorders, so that even minor trauma can lead to ulceration and infection. Careful observation and assessment of these wounds is essential to ensure the integrity of the limb is not threatened, which could result in amputation. A multidisciplinary team approach is the key to successful management of diabetic foot ulceration.