Search for the rare decays K(L)→π0π0μ+μ- and K(L)→π0π0X0→π0π0μ+μ-

The KTeV E799 experiment has conducted a search for the rare decays, K(L)→π(0)π(0)μ(+)μ(-) and K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-), where the X(0) is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3 ± 0.5) MeV/c(2). We find no evidence for either decay. We obtain upper limits of Br(K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-)) < 1.0 × 10(-10) and Br(K(L)→π(0)π(0)μ(+)μ(-)) < 9.2 × 10(-11) at the 90% confidence level. This result rules out the pseudoscalar X(0) as an explanation of the HyperCP result under the scenario that the dsX(0) coupling is completely real.

Multiparametric characterisation of the perihemorrhagic zone in a porcine model of lobar ICH

OBJECTIVES

To describe early perihemorrhagic changes after lobar intracerebral hemorrhage (ICH) using multiparametric neuromonitoring [intracranial pressure (ICP), cerebral blood flow (CBF), tissue oxygenation (PbrO2), microdialysis (MD)].

METHODS

Seven anaesthetized male swine were examined over 12 h. Four cerebral probes were inserted around the ICH (ICP, MD, CBF and PbrO2). A right frontal autologous arterial ICH (1.5 mL) was induced in all animals.

RESULTS

Initial ICH creation was hampered by using a soft 22-G cannula. A modified injection technique with a 90° bent steel cannula (20 G) allowed for an 87.5% success rate in ICH formation. After induction of ICH, ICP significantly increased from 2 mmHg to 9 mmHg. No significant PbrO2 or CBF reduction occurred during the monitoring period. Consequently, microdialysis did not indicate overall mean deterioration in the hematoma group over time. The indicator of ischemia (extracellular lactate) did not increase significantly during the monitoring period. Individual monitoring episodes demonstrated hypoxic episodes with consecutive metabolic derangement. These effects were reversible by optimizing CPP and FiO2.

CONCLUSION

We established a reproducible cortical ICH model using multiparametric neuromonitoring. Subtle changes in ICP were observed. No evidence for the existence of a perihemorrhagic ischemic area was found, hypothetically because of the small hematoma size. Individual animals underwent critical PbrO2 and CBF decreases with consecutive metabolic derangement. The effect of larger hematoma volumes should be evaluated with this setup in future studies to study volume-dependent deterioration.

HFE gene polymorphisms and severity in Portuguese patients with multiple sclerosis

BACKGROUND

High iron concentrations have been reported in oligodendrocytes, myelin and macrophages in multiple sclerosis (MS) lesions. It has been proposed that HFE gene polymorphisms could have a role in MS.

METHODS

The C282Y and H63D HFE variants frequencies were determined in 373 patients with MS and compared with a normal population.

RESULTS

No significant association was found between HFE polymorphisms and disease susceptibility. An analysis of the association of genotypes with disease severity was performed, and the C282Y allele was more frequent in the aggressive group.

CONCLUSIONS

Patients carrying the C282Y variant seem to have a worse prognosis.

Primary antiphospholipid antibody syndrome presenting with encephalopathy, psychosis and seizures

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by recurrent thrombotic events, miscarriages and thrombocytopenia with persistently positive antiphospholipid antibodies. 1 , 2 APS may be isolated (primary APS) or associated to a connective tissue disease, most often systemic lupus erythematosus (SLE). 1 , 2 APS usually affects young patients before the fifth decade 3 with stroke being the commonest neurological manifestation. 4 Various other neurological manifestations are being recognized in patients with APS including migraine, epilepsy, multi-infarct dementia and chorea. 2 The pathological process underlying the neurological manifestations remains obscure. 1 , 2 Herein we report a case of primary APSpresenting with a group of unusual neurological manifestations in a 68-year-old woman.

Intrinsic stability and hydrogen affinity of pure and bimetallic nanowires

A density functional theory study of the intrinsic stability of pure and bimetallic wires is presented. Several bimetallic combinations forming one-atom thick wires are studied. An explanation for the experimental instability of Cu wires in contrast to the stability of Au and Ag wires is given, which relies on the higher surface energy of the former. All the possible intercalations between Ni, Pd, Pt, Cu, Ag, and Au are studied. The bimetallic wires AuCu and AuAg were found to be the most stable ones. The reactivity of the latter two systems is also examined using hydrogen adsorption as a microscopic probe. It was found that at the inter-metal interface, up to second neighbors, Cu and Ag become more reactive and Au becomes more inert than the corresponding pure wires. These results are explained within the d-band model.

Maintenance treatment with cetuximab in a series of patients treated with standard chemotherapy and cetuximab in metastatic colorectal cancer

624

Background: New strategies are needed to improve outcomes and reduced toxicities of currently treatments for patients with advanced colorectal cancer. Nowadays maintaining treatment until disease progression is the standard option for these patients. Cetuximab is a recombinant humanized monoclonal antibody that neutralizes epidermal growth factor receptor and it has shown benefit not only in combination with standard chemotherapy in first- and second-line treatment or as a single agent in progression to standard chemotherapy in KRAS wild-type metastatic colorectal cancer (mCRC).

Methods: This data describes patients who received standard chemotherapy with cetuximab every two weeks. For patients with response or stable disease, cetuximab was continued until disease progression or unacceptable toxicity.

Results: Twelve patients are reported, nine were male (75%). The median age was 62 years (range, 46 to 78 years). All patients had stage IV, and liver was the most common location (75%). The majority of patients (75%) received FOLFOX VI as a first-line treatment in combination with cetuximab; only two patients were treated with FOLFIRI. Cetuximab was maintained after the first line of treatment in the 75% of patients. The median of cycles of chemotherapy and cetuximab was 12. Best response achieved in this setting was complete response (58.3%, 7/12). Median of monotherapy with cetuximab treatment was 7.5 cycles (range 3 to 12). At the moment of this analysis seven of twelve patients continued with the maintenance. In the rest of patients the treatment was followed until progression (33%, 3/12). No grade 3-4 toxicities were seen during maintenance cetuximab. The most common adverse effect during maintenance was cutaneous toxicity but the majority of patients had minor toxicity (50% grade 1).

Conclusions: Cetuximab has significant antitumor activity not only as a single agent or in combination with standard chemotherapy but may also when it is used as maintenance therapy after a complete or partial response to first or second line based chemotherapy in mCRC. Maintenance cetuximab is feasible, safe, and worthy of future study in advanced colorectal cancer.

No significant financial relationships to disclose.

Cerebral microdialysis in acutely brain-injured patients with spreading depolarizations

Multimodal cerebral monitoring was utilized to examine the relationship between pathological changes in microdialysis parameters and the occurrence of spreading depolarizations (SD) in brain-injured patients. SD are a relatively newly discovered phenomenon in man found to be linked to secondary insults and infarct growth and they can be detected via electrocorticography (ECoG). A total of 24 brain-injured patients (mean age: 52±11 years) requiring craniotomy took part in this prospective observational study. Each patient was monitored with a linear strip electrode for ECoG data and a cerebral microdialysis probe. SD were detected in 13 of the 24 patients. Pathological concentrations of glucose and lactate in brain parenchyma were significantly correlated with various time points prior to and/or immediately following the SD. Severe systemic hyperglycemia and systemic hypoglycemia were also found to be correlated with the occurrence of SD. The present study shows a clear relationship between SD and pathological changes in cerebral metabolism; further studies are needed to elucidate these complex interactions with the ultimate goal of developing therapeutic strategies for improving outcome in brain-injured patients.

Proboscis length and resource utilization in two Uruguayan bumblebees: Bombus atratus Franklin and Bombus bellicosus Smith (Hymenoptera: Apidae)

Bumblebees (Bombus sp.) are eusocial insects with an annual life cycle whose use as pollinator of crops has gained great importance in modern agriculture. Several authors have found that resource use in Bombus species is usually based on the correlation between the proboscis length of the bumblebees and the corolla depth of the flowers. The aim of this study was to determine proboscis length of Bombus atratus and B. bellicosus, two Uruguayan bumblebees, and verify the resource exploitation testing two cultivated species, the red clover and the bird's foot trefoil. Bumblebee foraging activity was recorded in two culture conditions: in a red clover and bird's foot trefoil mixed meadow, and in contiguous plots of these legumes, and the proboscis length of collected foragers was determined. Both species of bumblebees exploited red clover and bird's foot trefoil although they did it in different proportions in all instances tested. The results indicated that the choice of the resources in B. atratus and B. bellicosus was influenced by their proboscis length. Bombus atratus has a longer proboscis and preferably visited red clover, possibly obtaining nectar easier and faster than B. bellicosus, which has a shorter proboscis. Bombus bellicosus used both resources without any clear preference.

Extracorporeal photopheresis in addition to pentostatin in conditioning for canine hematopoietic cell transplantation: role in engraftment

Extracorporeal photopheresis (ECP) and the purine analog pentostatin exert potent immunomodulatory effects, but have not been evaluated for their ability to enhance engraftment of hematopoietic stem cells. We evaluated, in a canine model of dog leukocyte antigen (DLA)-identical hematopoietic cell transplantation (HCT), whether ECP in combination with pentostatin could enhance engraftment using a nonmyeloablative regimen consisting of 100 cGy TBI and postgrafting immunosuppression with mycophenolate mofetil and CYA. We have shown previously that with 100 cGy TBI alone as conditioning, all of the six dogs rejected their grafts 2-12 weeks after HCT. With the addition of pentostatin to 100 cGy TBI, 6 of 10 dogs rejected their graft. We now tested the additional use of ECP alone (n=2) or ECP and 3-6 doses of pentostatin (n=7) before 100 cGy TBI and HCT. Eight out of nine dogs rejected their grafts within 6-11 weeks after HCT. Compared with data without ECP, we failed to demonstrate a positive impact of the use of either ECP or pentostatin for prevention of rejection.

Sedation with propofol controlled by endoscopists during percutaneous endoscopic gastrostomy

BACKGROUND

propofol is a hypnotic used with increasing frequency for sedation during endoscopic procedures. Most of the reports published related with its employment by non-anaesthesiologists, refers to basic endoscopy, with little reference to its use in advanced endoscopy.

OBJECTIVE

to evaluate the efficacy and safety of propofol sedation administered by endoscopists, while performing percutaneous endoscopic gastrostomy, an advanced technique that is usually performed in high anesthetic level risk patients.

MATERIAL AND METHODS

prospective study of a series of endoscopic gastrostomy performed consecutively in our department; the sedation was carried out exclusively with propofol. The staff in the room consisted of two medical gastroenterologists, a nurse and a nursing assistant. Propofol was administered by bolus doses adjusted to patient weight. Arterial oxygen saturation, heart rate and blood pressure were monitored; respiratory activity was monitored visually by observing respiratory excursions of the patient.

RESULTS

we included 47 patients, with an average age of 82 years. 87% were ASA III and the rest, ASA IV. The mean dose of propofol was 51 mgr. Complications were recorded: 8 cases of desaturation and two of hypotension, all of them minor and quickly reversible. All procedures were carried out successfully, at a median time of 8 minutes.

CONCLUSION

the propofol sedation carried out by non-anaesthesiologist trained staff, seems to appear as a safe and effective procedure while performing percutaneous endoscopic gastrostomy.

Caracterización sanitaria y nutricional de colonias de abejas melíferas en forestaciones de Eucalyptus grandis

En Uruguay muchos apicultores trasladan sus colonias a las forestaciones de Eucalyptus grandis al final del verano y en otoño obteniendo importantes cosechas de miel. Sin embargo, cuando finaliza la floración las colonias se encuentran muy debilitadas, sobreviniendo una elevada mortalidad. Problemas nutricionales y sanitarios podrían explicar el debilitamiento de las colonias. Para averiguar las causas del debilitamiento se llevaron colonias de igual tamaño a una forestación de E. grandis, separadas en tres grupos diferenciados por la disponibilidad de polen. A lo largo del periodo de floración se registró: el origen botánico y el contenido de proteína cruda del polen que ingresaba en las colmenas, la proteína corporal de las abejas, la infección por Nosema ceranae y la infestación por Varroa destructor, el área de cría y la producción de miel. Los resultados más importantes hallados fueron: i) la sostenida disminución de la diversidad botánica del polen a medida que transcurría el periodo de floración de E. grandis hasta quedar únicamente el polen de esta especie; ii) el polen de E. grandis presentó valores de proteína bruta cercanos al 30%, pero fue disminuyendo paulatinamente hasta alcanzar un valor inferior a 20% al final de la floración; iii) las colonias que contaban inicialmente con reservas de polen presentaron abejas con mayor proteína corporal pocos días después de llegar a la forestación y menor infestación de N. ceranae durante la mayor parte del periodo de floración; iv) la disponibilidad de polen no incidió en la infestación de V. destructor, el área de cría y la producción de miel. El déficit nutricional de las abejas durante la floración de E. grandis podría generar las condiciones adecuadas para la multiplicación de N. ceranae. Al final de la floración del eucalipto las colonias presentaron promedialmente más del 90% de las abejas pecoreadoras infectadas con N. ceranae y 12% de V. destructor en las abejas adultas. La incidencia de ambos patógenos sobre las abejas debilitadas podría explicar la pérdida de colonias.

Measurement of the depth of maximum of extensive air showers above 10{18} eV

We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) g/cm{2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.