Working memory features are embedded in hippocampal place fields

Hippocampal principal neurons display both spatial tuning properties and memory features. Whether this distinction corresponds to separate neuron types or a context-dependent continuum has been debated. We report here that the task-context ("splitter") feature is highly variable along both trial and spatial position axes. Neurons acquire or lose splitter features across trials even when place field features remain unaltered. Multiple place fields of the same neuron can individually encode both past or future run trajectories, implying that splitter fields are under the control of assembly activity. Place fields can be differentiated into subfields by the behavioral choice of the animal, and splitting within subfields evolves across trials. Interneurons also differentiate choices by integrating inputs from pyramidal cells. Finally, bilateral optogenetic inactivation of the medial entorhinal cortex reversibly decreases the fraction of splitter fields. Our findings suggest that place or splitter features are different manifestations of the same hippocampal computation.

Can cholesterol be too low? A retrospective correlation of cholesterol lab values to other markers of cardiovascular disease risk

Introduction/Objective

Most recommendations for lipid panel reference ranges are one-sided (desirable total cholesterol is <200 mg/dL, optimal LDL cholesterol [LDL-C] is <100 mg/dL). However, recent studies suggest risks for cardiovascular diseases or mortality at very low cholesterol values. In this retrospective study, we investigated the association between lipid panel results and surrogate markers of cardiovascular disease to test the hypothesis that very low cholesterol levels are associated with increases in cardiovascular risk.

Methods/Case Report

Patients with lipid panels reported from April 2020-March 2021 at LAC+USC Medical Center were included. Lipid panels (total cholesterol, LDL-C, HDL-C, triglycerides) and laboratory results representing risk factors for cardiovascular disease (troponin T (TnT), NT-pro brain natriuretic peptide (BNP), hemoglobin A1c (HbA1c), high sensitivity C-reactive protein (CRP)) were collated. Lipid panel values were compared against the percentage of patients with non-optimal laboratory results for the cardiovascular risk markers.

Results (if a Case Study enter NA)

Decreasing total cholesterol levels vs. the percentage of patients with high TnT or BNP showed a U-curve with a nadir at 200-240 mg/dL (elevated TnT: 15%, BNP: 49%) and further increased with lower cholesterol levels <60 mg/dL (TnT: 56%, BNP: 92%); HbA1c (U-curve, nadir: 160-180 mg/dL); and CRP (90% at cholesterol <60 mg/dL; 43% at 220-240 mg/dL). Decreasing HDL-C against all markers of cardiovascular disease demonstrated a continued downtrend below optimal HDL-C levels. Decreasing LDL-C vs. the percentage of high TnT showed a U-curve with a nadir at 120-140 mg/dL; BNP (uptrends in the optimal range of LDL-C); HbA1c (U-curve, nadir: 90-100 mg/dL); and CRP (uptrends with decreasing LDL-C). TnT and BNP decreased with increasing triglycerides, while HbA1c increased with increasing triglycerides. Data points (TnT: n > 5,000; BNP: n > 3,000; HbA1c: n > 29,000; CRP: n > 4,500).

Conclusion

Very low concentrations of total cholesterol and LDL-cholesterol are associated with elevated markers of cardiovascular risk. Laboratories may wish to consider incorporating low ends to total cholesterol and LDL-cholesterol reference ranges.

The efficiency of hypogammaglobulinemia reflex immunofixation electrophoresis in identifying monoclonal proteins

Introduction/Objective

Hypogammaglobulinemia can be a common occurrence in disorders with monoclonal gammopathies. Because hypogammaglobulinemia may mask a monoclonal protein on serum protein electrophoresis (sPEP), its presence in the absence of a discernible M-spike is often the basis of reflexive testing by immunofixation electrophoresis (IFE). At our Institution, reflex IFE has historically been performed in cases where the gamma fraction on sPEP is <0.6 g/dL. The aim of this study was to test the predictive performance of hypogammaglobulinemia in identifying abnormal bands on IFE in newly screened patients.

Methods/Case Report

All patients that underwent sPEP testing from November 2020 to May 2021 at our Institution were identified. Among them, patients with gamma fraction <0.6 g/dL and no previous sPEP testing were included for analysis. Reflex IFE results were reviewed for identification of abnormal bands.

Results (if a Case Study enter NA)

Out of a total number of 1,374 patients tested for sPEP in the study period, 72 had serum gamma fraction <0.6 g/dL (5.2%). Among them, 36 patients had no previous sPEP testing, and their reflex IFE were reviewed. In 38.8% of the cases, the IFE showed one or more abnormal (monoclonal) bands. When considering a new threshold for hypogammaglobulinemia IFE reflex of <0.4 g/dL, the diagnostic yield for finding abnormal bands increased to 62.5%. Moreover, a percentage reduction of 64.2% was observed in the number of reflex IFE performed.

Conclusion

Although these data must be confirmed using a larger sample population, a lower threshold for hypogammaglobulinemia may be proposed at our Institution to reduce labor and costs and to improve efficiency of monoclonal protein detection.

Emerging responses to the COVID-19 crisis from family farming and the agroecology movement in Latin America - A rediscovery of food, farmers and collective action

CONTEXT

In Latin America, the so-called informal sector associated with family farming and the agroecology movements were instrumental at coping with and adapting to the COVID-19 challenges.

OBJECTIVE

To assess the nature and extent of the early initiatives (first three months) deployed by this informal sector to cope with and adapt to the impacts of the COVID-19 pandemic on food production and consumption in several countries of the region.

METHODS

We used key used informant consultation (n = 168), an online survey (n = 125) and the detailed characterisation of regional case studies (n = 4). Textual data was analysed and categorised using Reinert's method, combined with similarity analysis.

RESULTS AND CONCLUSIONS

65% of the initiatives were 'local' in terms of geographic reach, 30% of them started within the first month after the pandemic and most of them were urban or urban-rural, whereas only 29% of them were exclusively rural. The analysis of the textual information captured through the survey revealed four major types of initiatives that were deployed or adapted in response to COVID-19:1.Direct producer-to-consumer food sales, generally existing before the COVID-19 crisis but adapted/strengthened to cope with it;2.Short value chains that linked rural and urban organisations and individuals supported by national or local governments, readapted through new health and safety protocols;3.Newly developed support and training programs on sustainable food production for self-consumption or local commerce, in rural, urban or peri-urban settings;4.Food assistance and aid initiatives focusing on vulnerable populations, relying on solidarity networks associated with the agroecological movement.

SIGNIFICANCE

The pandemic highlighted the key role played by local food systems and value chains and the need to strengthening them through public policies, as a way to build food resilience in times of crisis.

Detection of meticillin-resistant Staphylococcus aureus and carbapenemase-producing Enterobacteriaceae in Danish emergency departments - evaluation of national screening guidelines

BACKGROUND

Multi-resistant bacteria (MRB) are an emerging problem. Early identification of patients colonized with MRB is mandatory to avoid in-hospital transmission and to target antibiotic treatment. Since most patients pass through specialized emergency departments (EDs), these departments are crucial in early identification. The Danish National Board of Health (DNBH) has developed exposure-based targeted screening tools to identify and isolate carriers of meticillin-resistant Staphylococcus aureus (MRSA) and carbapenemase-producing Enterobacteriaceae (CPE).

AIM

To assess the national screening tools for detection of MRSA and CPE carriage in a cohort of acute patients. The objectives were to investigate: (i) if the colonized patients were detected; and (ii) if the colonized patients were isolated.

METHODS

This was a multi-centre cross-sectional survey of adults visiting EDs. The patients answered the DNBH questions, and swabs were taken from the nose, throat and rectum. The collected samples were examined for MRSA and CPE. Screening performances were calculated.

FINDINGS

Of the 5117 included patients, 16 were colonized with MRSA and four were colonized with CPE. The MRSA screening tool had sensitivity of 50% [95% confidence interval (CI) 25-75%] for carrier detection and 25% (95% CI 7-52%) for carrier isolation. The CPE screening tool had sensitivity of 25% (95% CI 1-81%) and none of the CPE carriers were isolated.

CONCLUSION

The national screening tools were of limited use as the majority of MRSA and CPE carriers passed unidentified through the EDs, and many patients were isolated unnecessarily.

Effect of Fixed Minidose Warfarin, Conventional Dose Warfarin and Aspirin on INR and Prothrombin Fragment 1 + 2 in Patients with Atrial Fibrillation

The efficacy of conventional dose adjusted oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation is well- documented but not considered ideal as primary antithrombotic treatment in elderly patients. The antithrombotic effect of fixed minidose warfarin 1.25 mg/day alone or in combination with aspirin 300 mg/day, of conventional dose adjusted warfarin (INR 2.0-3.0), and of aspirin 300 mg/day have been investigated in outpatients with chronic nonvalvular atrial fibrillation in the second Copenhagen Atrial Fibrillation, Aspirin and Anticoagulant Therapy Study (AFASAK 2). In order to investigate the effect on the coagulation system of the treatments, the International Normalized Ratio of the prothrombin time (INR) and prothrombin fragment 1 + 2 (F1 +2) were monitored at baseline and after three months of treatment in 100 patients consecutively included in the trial. At baseline no differences in INR and F1+2 between the four treatment groups were present. After three months of therapy the level of INR increased significantly from baseline in patients receiving warfarin in any dose and the level of F1+2 decreased significantly by combined minidose warfarin-aspirin and by dose adjusted warfarin. When comparing the changes over time in FI +2 (three-month value minus baseline value) during therapy with fixed minidose warfarin, combined minidose warfarin-aspirin and aspirin alone no significant difference between the groups was found. In conclusion, INR was changed by all three warfarin regimens but only dose adjusted warfarin (INR 2.0-3.0) had a marked effect on F1+2.

Effect of Organ Scandal on Corneal Donation Rate and Organ Donors at a German University Hospital

BACKGROUND The purpose of this study was to assess the effect of an organ transplantation scandal on the rate of corneal donations and organ donors at the University Hospital Tübingen. MATERIAL AND METHODS Data from all hospital deaths from January 2012 to December 2013 were analyzed retrospectively. Each deceased patient was considered as a potential corneal donor. The corneal donor procurement was handled by an ophthalmic resident on a full-time basis with standard used unchanged set of procedures. Each patient who died due to cerebral complications was considered as a potential organ donor. During the two-year period, a German transplantation scandal occurred at the end of 2012 and received worldwide attention. The rates of corneal donation and organ donation in 2012 and 2013 were examined and evaluated. RESULTS Among the 1685 deceased patients, approval for corneal donation was received in 220 cases (13.1%): 124 cases (15.0%) in 2012 and 96 cases (11.2%) in 2013. This corresponds to a decline of 23%. The leading causes of nonfulfillment of corneal donations were refusal to donation: 401 cases (48.4%) in 2012 and 445 cases (52.0%) in 2013; and medical contraindications: 201 cases (24.2%) in 2012 and 212 cases (24.8%) in 2013. During the two-year period, consent for organ donation was obtained in 25 cases (1.5%): 15 cases (1.8%) in 2012 and 10 cases (1.2%) in 2013. The number of realized organ donors was 20 cases (1.2%): 12 cases (1.4%) in 2012 and 8 cases (0.9%) in 2013. This corresponds to a decline of 33%. CONCLUSIONS After a transplantation scandal, the number of realized corneal donors and realized organ donors decreased significantly. It seems that increasing professional performance is very important to gaining trust inside and outside the hospital and improving corneal and organ donation rate.

Encapsulation of Islets in Rough Surface, Hydroxymethylated Polysulfone Capillaries Stimulates VEGF Release and Promotes Vascularization after Transplantation

The transplantation of encapsulated islets of Langerhans is one approach to treat type 1 diabetes without the need of lifelong immunosuppression. Capillaries have been used for macroencapsulation because they have a favorable surface-to-volume ratio and because they can be refilled. It is unclear at present whether the outer surface of such capillaries should be smooth to prevent, or rough to promote, cell adhesions. In this study we tested a new capillary made of modified polysulfone (MWCO: 50 kDa) with a rough, open-porous outer surface for islet transplantation. Compared with free-floating islets, encapsulation of freshly isolated rat islets affected neither the kinetics nor the efficiency of glucose-induced insulin release in perifusion experiments. Free-floating islets maintained insulin secretion during cell culture but encapsulated islets gradually lost their glucose responsiveness and released VEGF. This indicated hypoxia in the capillary lumen. Transplantation of encapsulated rat islets into diabetic rats significantly reduced blood glucose concentrations from the first week of implantation. This hypoglycaemic effect persisted until explantation 4 weeks later. Transplantation of encapsulated porcine islets into diabetic rats reduced blood glucose concentrations depending on the islet purity. With semipurified islets a transient reduction of blood glucose concentrations was observed (2, 8, 18, 18 days) whereas with highly purified islets a sustained normoglycaemia was achieved (more than 28 days). Explanted capillaries containing rat islets were covered with blood vessels. Vascularization was also observed on capillaries containing porcine islets that were explanted from normoglycaemic rats. In contrast, on capillaries containing porcine islets that were explanted from hyperglycemic rats a fibrous capsule and lymphocyte accumulations were observed. No vascularization on the surface of transplanted capillaries was observed in the absence of islets. In conclusion, encapsulated islets can release VEGF, which appears to be an important signal for the vascularization of the capillary material. The rough, open-porous outer surface of the polysulfone capillary provides a site well suited for vascular tissue formation and may allow a prolonged islet function after transplantation.

Clinical and morphological aspects of adenocarcinomas of the intestinal type in the inner nose: a retrospective multicenter analysis

Clinical and histological parameters from 117 patients with wood dust-related sinonasal adenocarcinomas of intestinal type (ITAC) were analyzed and correlated with a follow-up period of 5 years at least. The rate of survival for 5 years was 53.1 % and for 10 years 30.2 %. Only 33 patients were free of disease. 74.2 % of patients with recurrences died in relation to ITAC. As expected, tumors of T4-category had the worst prognosis. The mucus content of a tumor was the most important histological parameter. Endonasal methods of surgery had no more positive survival rates after 5 years. An effect of radiotherapy has to be in discussion. The high incidence of tumor recurrences requires control examinations consistently.

A Phase II, double-blind, randomized, parallel group, dose-finding study of the safety and tolerability of darexaban compared with warfarin in patients with non-valvular atrial fibrillation: the oral factor Xa inhibitor for prophylaxis of stroke in atrial fibrillation study 2 (OPAL-2)

BACKGROUND

Darexaban (YM150) is a novel oral anticoagulant that directly inhibits factor Xa.

OBJECTIVES

To investigate the optimal daily dose regimen of YM150 in subjects with non-valvular atrial fibrillation (NVAF).

METHODS

In this multicenter, double-blind, double-dummy, randomized, parallel-group, dose-confirmation study (NCT00938730), patients with NVAF were randomized to darexaban 15 mg bid, 30 mg qd, 30 mg bid, 60 mg qd, 60 mg bid or 120 mg qd, or warfarin qd. The primary endpoint was the incidence of adjudicated major and/or clinically relevant non-major bleeding events. Secondary endpoints included efficacy, pharmacodynamics, safety and tolerability.

RESULTS

A total of 1297 patients were randomized and finally included in the trial (median age, 66 [range 30-89] years; 68.8% male): 981 completed treatment for a median of 28 weeks (interquartile range, 24-36). At daily doses of 30-60 mg, darexaban bid resulted in fewer bleeding events than darexaban qd. For darexaban 120 mg, the bid regimen produced more bleeding events than the qd regimen. Although few efficacy endpoints occurred, these decreased with increasing daily darexaban dose. Darexaban decreased plasma D-dimer levels (index of thrombogenesis) after 4 weeks of treatment by 21.5-33.8% compared with baseline, which was comparable with warfarin at the higher darexaban doses. Darexaban was well tolerated with no liver toxicity.

CONCLUSIONS

In this Phase II study in patients with NVAF, a lower bleeding rate was observed in the 120 mg daily darexaban group compared with warfarin with a reduction in plasma D-dimer as marker for hemostasis. Further investigation of the optimal dose of darexaban for the prevention of stroke in patients with NVAF would need to be considered.

Improving hand hygiene compliance in the emergency department: getting to the point

Background

The emergency department (ED) represents an environment with a high density of invasive, and thus, infection-prone procedures. The two primary goals of this study were (1) to define the number of hand-rubs needed for an individual patient care at the ED and (2) to optimize hand hygiene (HH) compliance without increasing workload.

Methods

Prospective tri-phase (6-week observation phases interrupted by two 6-week interventions) before after study to determine opportunities for and compliance with HH (WHO definition). Standard operating procedures (SOPs) were optimized for invasive procedures during two predefined intervention periods (phases I and II) to improve workflow practices and thus compliance with HH.

Results

378 patient cases were evaluated with 5674 opportunities for hand rubs (HR) and 1664 HR performed. Compliance significantly increased from 21% (545/2603) to 29% (467/1607), and finally 45% (652/1464; all p<0.001) in phases 1, 2, and 3, respectively. The number of HR needed for one patient care significantly decreased from 22 to 13 for the non-surgical and from 13 to 7 for the surgical patients (both p<0.001) due to improved workflow practices after implementing SOPs. In parallel, the number of HR performed increased from 3 to 5 for non-surgical (p<0.001) and from 2 to 3 for surgical patients (p=0.317). Avoidable opportunities as well as glove usage instead of HR significantly decreased by 70% and 73%, respectively.

Conclusions

Our study provides the first detailed data on HH in an ED setting. Importantly, HH compliance improved significantly without increasing workload.

Atrial fibrillation--a review of course and prognosis

Four recent major studies concerning the prognosis in atrial fibrillation (AF) are reviewed. The one-year mortality ranged from 16.0 to 0.2%, highest in elderly, hospitalized patients with chronic AF and lowest in young individuals with paroxysmal AF without other heart disease. The recognized clinical impression that the prognosis in AF is determined by age, type of AF and clinical status is thus confirmed. In three studies, however, the prognosis in lone atrial fibrillation seemed to be poorer than previously thought. The overall rate of thromboembolic complications in AF was about 25% in several studies. The effectiveness of coumarin drugs in the prophylaxis of these complications is not proved, and the time has come to subject them to more careful clinical investigation.

Digoxin-trimethoprim interaction

Nine patients (median age 78 years, range 62-92) treated with a constant oral dosage of digoxin were evaluated for the effect of trimethoprim on serum digoxin values. Serum digoxin increased by 22% during trimethoprim treatment (p less than 0.05). Subsequently, 6 healthy subjects (median age 29 years, range 24-31) were evaluated for the effect of trimethoprim on digoxin pharmacokinetics after an i.v. dose. Trimethoprim administration did not affect total body clearance of digoxin and the glomerular filtration rate. The renal clearance of digoxin decreased by 17% (p less than 0.05) and the extrarenal clearance of digoxin increased by 14% (N.S.). Biological half-life of digoxin and apparent volumes of central and peripheral compartments were unchanged during the study. It is suggested that the increase in serum digoxin in the elderly patients is due to decreased renal tubular secretion of digoxin and not to disturbance of the extrarenal clearance.

Trend reversal in the frequency of mycoses in hematological neoplasias: autopsy results from 1976 to 2005

INTRODUCTION

Fungal infections of internal organs are a major complication for patients with hematological neoplasias. For more than 20 years, the frequency of such mycoses has been increasing with the aggressiveness of tumor treatment.

METHODS

Autopsy findings over a 30-year period (1976 to 2005) from a single institution (Institute of Pathology, University of Essen) were retrospectively classified according to basic disease, frequency of mycoses, kind of mycoses, organs involved, hematopoietic transplantation, and cause of death.

RESULTS

340 of 1591 autopsied patients with hematological neoplasias (21.4%) revealed an invasive mycosis. The proportion increased from about 10% before 1980 to some 30% in the 1990s but fell to 21% by 2005. The frequency of mycoses decreased significantly both for transplanted patients (from 47.5% to 30.3%) and for non-transplanted patients (from 29.8% to 16.4%). The rate of deaths due to mycosis also decreased. The relative frequency of candidal mycoses went down, while aspergilloses predominated. The organ most frequently involved was the lung.

DISCUSSION

The autopsy results signal a trend reversal in the leading complication of the treatment of hematological neoplasias and lend support to the assumption that antimycotic strategies are having a positive effect.

A novel photodiode for reflectance pulse oximetry in low-power applications

The amount of light collected is crucial for low-power applications of pulse oximetry. In this work a novel ring-shaped backside photodiode has been developed for a wearable reflectance pulse oximeter. The photodiode is proven to work with a dual LED with wavelengths of 660 nm and 940 nm. For the purpose of continuously monitoring vital signs of a human, a temperature sensor is integrated onto the chip containing the photodiode. This biomedical multisensor chip is made for integration into "the Electronic Patch", an autonomous monitoring system for humans.

WFD and agriculture activity of the EU: first linkages between the CAP and the WFD at EU level

Within the "WFD and agriculture activity" both communities agreed to co-operate during implementation of the Water Framework Directive (WFD) and further development of the Common Agricultural Policy (CAP) at EU, Commission and the Member States levels. In intensive discussions including two congresses and biannual working group meetings, seven information reports were produced. Rural Development programmes are unanimously considered to be very powerful instrument to support WFD implementation. However, limited budgets, combined with the large extent of agricultural pressures will considerably restrain the results this instrument might deliver. Limited effects are also expected from the cross-compliance standards, mainly because: the standards do not cover all WFD aspects, and the existing legislation is not implemented with the same rigour in all the Member States. WFD provides additional powerful tools (River Basin Management Planning and Water Pricing discussion) to improve the situation, but the timetables of WFD and CAP do not fit each other. The activity should be continued with an intensive discussion on case and success stories in all the mentioned tools informing both policy areas for the planned evaluation of cross-compliance in 2007, and a mid-term evaluation on rural development in 2009.

Secondary syphilis after liver transplantation: case report and review of the literature

Syphilitic disease is uncommon, but its incidence has increased worldwide in the last few years. An unusual manifestation of secondary syphilis after orthotopic liver transplantation is described which confirms that lues should be considered in patients with immune deficiency and abnormal liver function tests.

Low rate of progressive disease in metastatic gastric cancer using tandem chemotherapy with four active compounds

14069

Background: Taxanes and irinotecan have significantly increased the therapeutic options in the treatment of metastatic gastric cancer. However, the potential of all active substances is highest in first - line treatment. The rate of second remissions is low and survival after relapse is short. We performed a phase II study incorporating 5FU, irinotecan, cisplatin and docetaxel in a tandem protocol for first line treatment of patients with metastastic adenocarcinoma of stomach or cardia. Methods: Chemonaive patients received a 30-minute infusion of irinotecan 80 mg/m2 followed by IV bolus leucovorin 20 mg/m2 and infusional 5FU 2000 mg/m2 over 24 hours on days 1, 8 and 15. The second block included docetaxel 25 mg/m2 over 60 minutes followed by a 30-minute infusion of cisplatin 40 mg/m2 on days 29, 36 and 43. Patients were scheduled to receive two complete cycles. Primary objective was evaluation of remission rate. Further objectives were toxicity and overall survival. Results: 32 patients were included, 25 patients are currently evaluable. The median age was 56 years (36 - 72), 10 female and 15 male patients. 10/25 (40%) patients achieved a partial remission, 3 of these 10 patients had a very good partial remission. 13 (52%) patients had stable disease, and 2 (8%) patients progressed early. Main toxicities grade ≥ 3 were diarrhea (8/50 cycles), nausea and vomiting (3/50), neutropenia (2/50), anemia (1/50) and renal insufficiency (1/50). The median survival time was 11.7 months. Conclusions: This treatment schedule includes the four most active substances in the treatment of metastastic gastric cancer in a tandem protocol. Only 2/25 patients had progressive disease under therapy. Toxicity was moderate. Dose intensication may further increase the remission rate.

No significant financial relationships to disclose.

A novel MATE family efflux pump contributes to the reduced susceptibility of laboratory-derived Staphylococcus aureus mutants to tigecycline

Tigecycline, an expanded-broad-spectrum glycylcycline antibiotic is not affected by the classical tetracycline resistance determinants found in Staphylococcus aureus. The in vitro selection of mutants with reduced susceptibility to tigecycline was evaluated for two methicillin-resistant S. aureus strains by serial passage in increasing concentrations of tigecycline. Both strains showed a stepwise elevation in tigecycline MIC over a period of 16 days, resulting in an increase in tigecycline MIC of 16- and 32-fold for N315 and Mu3, respectively. Transcriptional profiling revealed that both mutants exhibited over 100-fold increased expression of a gene cluster, mepRAB (multidrug export protein), encoding a MarR-like transcriptional regulator (mepR), a novel MATE family efflux pump (mepA), and a hypothetical protein of unknown function (mepB). Sequencing of the mepR gene in the mutant strains identified changes that presumably inactivated the MepR protein, which suggested that MepR functions as a repressor of mepA. Overexpression of mepA in a wild-type background caused a decrease in susceptibility to tigecycline and other substrates for MATE-type efflux pumps, although it was not sufficient to confer high-level resistance to tigecycline. Complementation of the mepR defect by overexpressing a wild-type mepR gene reduced mepA transcription and lowered the tigecycline MIC in the mutants. Transcription of tet(M) also increased by over 40-fold in the Mu3 mutant. This was attributed to a deletion in the promoter region of the gene that removed a stem-loop responsible for transcriptional attenuation. However, overexpression of the tet(M) transcript in a tigecycline-susceptible strain was not enough to significantly increase the MIC of tigecycline. These results suggest that the overexpression of mepA but not tet(M) may contribute to decreased susceptibility of tigecycline in S. aureus.

Centralization: its prognostic value in patients with referred symptoms and sciatica

STUDY DESIGN

Prospective, comparative cohort study.

OBJECTIVE

To investigate the prognostic significance of centralization in patients with subacute sciatica and referred symptoms.

SUMMARY OF BACKGROUND DATA

Previous studies have shown that centralization occurs commonly in the nonspecific low back population, and its occurrence is associated with a good prognosis. The phenomenon has never been evaluated in a population with sciatica and referred symptoms.

METHODS

The sample pool was 104 consecutive patients referred for investigation of possible disc herniation. Of these patients, 60 were recruited into the study and underwent a standardized mechanical evaluation using repeated end-range movements, while symptom response was monitored to expose 2 groups: centralization group (CG) and noncentralization group (NCG). All patients were treated in the same way and were followed for one year. If patients did not have improvement surgery was considered. Outcomes included back and leg pain, disability, Nottingham Health Profile, and surgical outcome.

RESULTS

There were 25 patients who were classified in the CG, 35 in the NCG, and other baseline characteristics were similar between groups. At 1, 2, and 3 months, the CG had significantly better outcomes than the NCG. At 2 months, the CG had more improvements in leg pain (P = 0.007), disability (P = <0.001), and Nottingham Health Profile (P = 0.001). After 1 year, disability was less in the CG (P = 0.029). In the CG, 3 patients underwent surgery, in the NCG, 16 (P = 0.01). The odds ratio for surgery in the NCG was 6.2.

CONCLUSION

Patients with sciatica and suspected disc herniation who have a centralization response to a mechanical evaluation will have significantly better outcomes. Patients who do not have centralization will be 6 times more likely to undergo surgery.

Encapsulation of islets in rough surface, hydroxymethylated polysulfone capillaries stimulates VEGF release and promotes vascularization after transplantation

The transplantation of encapsulated islets of Langerhans is one approach to treat type 1 diabetes without the need of lifelong immunosuppression. Capillaries have been used for macroencapsulation because they have a favorable surface-to-volume ratio and because they can be refilled. It is unclear at present whether the outer surface of such capillaries should be smooth to prevent, or rough to promote, cell adhesions. In this study we tested a new capillary made of modified polysulfone (MWCO: 50 kDa) with a rough, open-porous outer surface for islet transplantation. Compared with free-floating islets, encapsulation of freshly isolated rat islets affected neither the kinetics nor the efficiency of glucose-induced insulin release in perifusion experiments. Free-floating islets maintained insulin secretion during cell culture but encapsulated islets gradually lost their glucose responsiveness and released VEGF. This indicated hypoxia in the capillary lumen. Transplantation of encapsulated rat islets into diabetic rats significantly reduced blood glucose concentrations from the first week of implantation. This hypoglycaemic effect persisted until explantation 4 weeks later. Transplantation of encapsulated porcine islets into diabetic rats reduced blood glucose concentrations depending on the islet purity. With semipurified islets a transient reduction of blood glucose concentrations was observed (2, 8, 18, 18 days) whereas with highly purified islets a sustained normoglycaemia was achieved (more than 28 days). Explanted capillaries containing rat islets were covered with blood vessels. Vascularization was also observed on capillaries containing porcine islets that were explanted from normoglycaemic rats. In contrast, on capillaries containing porcine islets that were explanted from hyperglycemic rats a fibrous capsule and lymphocyte accumulations were observed. No vascularization on the surface of transplanted capillaries was observed in the absence of islets. In conclusion, encapsulated islets can release VEGF, which appears to be an important signal for the vascularization of the capillary material. The rough, open-porous outer surface of the polysulfone capillary provides a site well suited for vascular tissue formation and may allow a prolonged islet function after transplantation.

41EFFECTS OF MATURATION PERIOD OF PORCINE OOCYTES ON DEVELOPMENT FOLLOWING SOMATIC CELL NUCLEAR TRANSFER

Despite intensive research, porcine nuclear transfer is still characterized by low success rates. To determine the effect of maturation period of porcine oocytes on subsequent development following nuclear transfer, we investigated fusion rate, induction of activation and development to blastocyst stage of somatic cells. For this we used MII-oocytes after 38, 40, and 42h of maturation culture as recipients. Oocytes surrounded by a compact cumulus mass were selected and placed into North Carolina State University (NCSU) 37 oocyte maturation medium supplemented with 0.1mgmL−1 cysteine, 10ngmL−1 epidermal growth factor, 10% porcine follicular fluid, 50μm 2-mercaptoethanol, 0.5mgmL−1 cAMP, 10 IU each of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) for 22h in humidified air with 5% CO2 at 38.5°C. Subsequently the oocytes were moved to fresh NCSU37 maturation medium without cAMP, eCG and hCG and incubated for an additional 16, 18, and 20h. In the first experiment, a total of 878 MII-arrested oocytes were enucleated, fused with pig fetal fibroblasts in calcium-free medium and activated approximately 3h later with an electrical stimulus. This was followed by incubation in 6-dimethylaminopurine for 3h and subsequent analysis of development in vitro. Maturation period had no effect on the frequencies of fusion (87% v. 75% v. 84%, respectively), and cleavage (82% v. 81% v. 87%, respectively), but when MII-oocytes recovered at 40h of maturation were used as recipients, 41/279 (14,8%) the numbers of cloned embryos developing to the blastocyst stage on Day 7 of culture was significantly (ANOVA followed by multiple pairwise comparisons using Tukey test, 6 replicates, P&lt;0,05) higher than those of embryos reconstituted with oocytes collected at 38h (27/285, 9.6%) and 42h (16/314, 4.9%). In the second experiment, reconstructed embryos derived from oocytes matured for 40h were surgically transferred to the oviducts of synchronized German Landrace gilts. Transfers were made on the first day of standing oestrus within 3h of activation to assess their development in vivo. Synchronization was achieved by injections of 1500IU eCG followed by 500IU hCG 3 days later. Of 4 recipients receiving an average of 150 zygotes (range, 136 to 163), 2 became pregnant as determined by ultrasound between Days 25 and 35 of gestation. Of the two pregnant recipients, one subsequently farrowed 4 piglets on Day 115 of pregnancy. These results indicate that the maturation period is critical and affects development of porcine nuclear transfer embryos. This study was funded by the Deutsche Forschungsgemeinschaft (DFG; SFB265).

Areal density measurement is a convenient method for the determination of porcine islet equivalents without counting and sizing individual islets

The determination of islet mass is important for the normalization of islet experiments in the laboratory and for the precise dosing of islets for transplantation. The common microscopical analysis is based on individual islet sizing, calculation of the frequency distribution, and conversion into islet equivalents (IEQ), which is the volume of a spherical islet with a diameter of 150 microm. However, islets are of irregular form, which makes this determination user dependent, and the analysis is irreproducible once the original sample is discarded. This routine technique of islet quantification was compared with the analysis of areal density measurements. It was assumed that the entire area occupied by islets can be expressed in IEQ without sizing and counting individual islets. Porcine islets were isolated by continuous digestion/filtration and purified by gradient centrifugation. Purified islets were stained with dithizone and were repeatedly pictured under the microscope with random area selection. A total of 51 pictures was taken from 11 different purifications and stained islets were detected by digital image analysis. The correlation coefficient (r) between bothanalyses was 0.977 with an underestimation of islet yield by areal density detection (slope: 0.75 +/- 0.03). Areal density analysis per picture took about 1 min, which is about 10 times faster than the traditional method without increasing the method error (CV 2.1% vs. 2.7%). In summary, areal density measurements allow a rapid and reproducible estimation of IEQ without counting individual islets. It can be performed in a single step analysis without computer programming and is valuable for online determinations of islet yield preceding transplantation.

Sensory-motor responses to volume-controlled duodenal distension

Abstract Visceral perception and secondary peristalsis evoked by distension of the duodenum were studied in 10 healthy volunteers. An impedance planimetric probe for cross-sectional area (CSA) measurements inside a balloon and with three pressure channels was used. Balloon distensions were performed in the fed state with or without the administration of the antimuscarinic drug butylscopolamine. A modified questionnaire was used to assess the nonpainful and painful sensations. The total tension (T(total)) and the passive tension (T(passive)) were determined from the distensions without and with the administration of butylscopolamine, respectively. The active tension (T(active)) was T(total) - T(passive). The stepwise balloon distensions induced the first sensation at a volume of 33 +/- 3 mL. After administration of butylscopolamine the first sensation appeared at 42 +/- 1 mL. The perception score (PS) revealed an approximately linear increase as function of volume, CSA, pressure and tension after the first sensation. Butylscopolamine resulted in significant changes in PS score as function of volume, CSA and strain, but not as a function of pressure and tension. The frequency of the secondary peristalsis increased to the highest value (8.2 +/- 0.8 contractions min(-1)) at a volume of 21 mL. Butylscopolamine almost abolished the distension-evoked motility. T(total) and T(passive) increased nonlinearly as a function of volume, whereas T(active) increased up to a distension volume of 33 mL and then decreased at higher volumes. Hence, the conventional length-tension diagrams as known from studies of smooth muscle strips in vitro can be reproduced in the human duodenum in vivo. This new way of studying intestinal sensation and motility may prove to have both basic and clinical importance as both passive tissue structures and the sensorimotor function are tested.

Sensory and biomechanical responses to distension of the normal human rectum and sigmoid colon

BACKGROUND

Visceral pain is a major clinical problem. The aim of the present study was to compare the pain and biomechanical responses to standardized distension of the human colon.

METHODS

The relation between pain intensity and pressure, cross-sectional area (CSA) and tension-strain relations of the rectum and sigmoid colon were studied in 11 normal subjects following standardized distension using impedance planimetry. The bag was inflated stepwise with pressures up to 6 kPa. The subjects, who were blinded for the distension procedure, rated their pain intensity using an aggregate visual analogue score (VAS) combining the intensity of the feeling of air, urge to defecate and pain.

RESULTS

The distensions produced an initial rapid increase in CSA followed by a phase of slow increase until a steady state CSA was reached after 0.5-1 min. Several phasic contractions (observed as short-term decreases in the CSA) were recorded in the rectum from the end of the rapid phase to the end of distension at pressures from 1 to 5 kPa. The CSA in the rectum and sigmoid colon was 3,706 +/- 426 mm(2) and 2,305 +/- 426 mm(2) at the maximum bag pressure of 6 kPa (F = 52.4, p < 0.001). The tension-strain relation did not differ between the normal rectum and sigmoid colon. The VAS score for every modality (air, defecation and pain) revealed an increase in intensity as a function of pressure. The VAS score in the rectum and the sigmoid colon as a function of tension and strain did not show any differences.

CONCLUSIONS

The biomechanical properties in the sigmoid colon and rectum were alike. For a given wall tension and circumferential strain the sensibility seems equal in the rectum and the sigmoid colon. The observed difference in perception between the two segments was related to the greater CSA in the rectum.

In vitro test of new biomaterials for the development of a bioartificial pancreas

The implantation of macroencapsulated islets has the potential to restore endogenous insulin secretion in type 1 diabetics, with no need for lifetime immunosuppression. To match the physiological fluctuations of blood glucose concentrations with appropriate insulin release, the macroencapsulation material must combine immunoprotection with optimal diffusion properties for glucose and insulin. The impact of chemical modifications of polysulphone (PSU) capillary polymers with a cutoff of 50 kD on glucose-induced insulin secretion of macroencapsulated rat islets was studied in perifusion experiments. The insulin release of free-floating islets showed the typical rapid response to glucose stimulation. Total insulin release (AUC between minute 30 and 120 of perifusion) reached 117+/-22 ng/ml. Blending PSU with polyvinylpyrrolidone or sodium-dodecyl-sulfate was not suitable for islet macroencapsulation, since glucose-induced insulin release was absent or disturbed. Hydroxy-methylation (CH2OH) of PSU improved the secretory behavior of macroencapsulated islets depending on the degree of PSU substitution (DS 0.8, AUC 62+/-15 ng/ml; DS 1.8, 111+/-24 ng/ml). In highly substituted PSU-capillaries the kinetics of glucose-induced insulin release was very similar to that observed in free-floating islets. Two consecutive glucose stimulations potentiated insulin release of free-floating islets during the second period of stimulation. Furthermore, freshly isolated macroencapsulated islets responded with more efficient insulin secretion after the initial priming. In conclusion, in vitro membrane screening identified highly substituted hydroxy-methylated PSU as the material of choice for islet encapsulation in a bioartificial pancreas.

Prevalence of hereditary haemochromatosis in late-onset type 1 diabetes mellitus: a retrospective study

BACKGROUND

Although genotyping studies suggest that hereditary haemochromatosis is one of the most common genetic disorders in white people, it is still thought of as an uncommon disease. Our aim was to test the hypothesis that hereditary haemochromatosis is a disease often overlooked in patients with late-onset type 1 diabetes mellitus, a late manifestation of untreated iron overload.

METHODS

We did a retrospective study in which we genotyped for the C282Y and H63D mutations in the haemochromatosis gene in 716 unselected Danish patients who developed type 1 diabetes mellitus after age 30 years and 9174 controls from the general Danish population. We also screened for hereditary haemochromatosis by assessment of transferrin saturation.

FINDINGS

More patients with diabetes (n=9, relative frequency 1.26%, 95% CI 0.58-2.37) than controls (23, 0.25%, 0.16-0.38) were homozygous for C282Y (odds ratio 4.6, 2.0-10.1, p=0.0001). These patients had unrecognised signs of haemochromatosis. Transferrin saturation and ferritin concentrations ranged from 57% to 102% and 17 microg/L to 8125 microg/L, respectively. Frequency of compound heterozygosity (C282Y/H63D) did not differ between patients with diabetes (eight) and controls (131) (odds ratio 0.8, 95% CI 0.4-1.7). Positive and negative predictive values of transferrin saturation greater than 50%, in identification of C282Y homozygosity, were 0.26 and 1.00, respectively. A saturation of less than 50% therefore excluded C282Y homozygosity, whereas a saturation of more than 50% suggested C282Y homozygosity.

INTERPRETATION

Measurement of transferrin saturation followed by genetic testing could prevent liver and heart problems and improve life expectancy in patients with diabetes. Population screening before the onset of diabetes might improve the outlook of patients even further, but will be less cost effective.

Macroencapsulation of rat islets without alteration of insulin secretion kinetics

Transplantation of encapsulated islets may restore endogenous insulin secretion in type 1 diabetics with no need of lifetime immunosuppression of the recipient. A biomaterial should be developed which combined immunoisolation with rapid and efficient diffusion of glucose and insulin. Rat islets were macroencapsulated in capillaries (molecular cut off 50 kD) of differently modified polysulphone. Macroencapsulated islets were perifused to study the kinetics of glucose induced insulin secretion into the perifusion medium. Blending polysulphone (PSU) with poly vinyl pyrrolidone or sodium dodecyl sulphate was not suited for islet macroencapsulation since glucose induced insulin release was absent after encapsulation. Hydroxy methylation (CH2OH) of PSU improved the secretory behaviour of macroencapsulated islets depending on the degree of substitution (DS). At 0.8 DS glucose induced insulin secretion was delayed and inefficient. At maximal degrees of PSU-substitution (1.8) the kinetics of insulin release and the efficiency of insulin release were very similar to that observed of free floating islets. In conclusion, highly substituted hydroxy methylated polysulphone allows a rapid and efficient insulin release after macroencapsulation and is suited for the further development of a bioartificial pancreas.