Effect of the epidermal growth factor receptor antibody panitumumab on triggering of ADCC

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Targeted therapy against the epidermal growth factor receptor (EGF-R) has been introduced into clinical practice for several solid tumors. Thus far, EGF-R- directed antibodies have received approval for the treatment of advanced colorectal and head and neck cancer. Recent studies demonstrated an association between Fcg receptor polymorphisms and clinical outcome. Here, we investigated effector mechanisms of the human IgG2 antibody pantitumumab and zalutumumab—a human IgG1 antibody against EGF-R, currently in phase III clinical evaluation. Both antibodies had similar binding characteristics, but differed in induction of antibody- dependent cellular cytotoxicity (ADCC). Zalutumumab induced potent MNC-mediated ADCC via FcgRIII (CD16), which was poorly triggered by panitumumab. Interestingly, not only zalutumumab but also panitumumab recruited neutrophils for ADCC. Neutrophil- mediated killing is triggered via FcgRIIa (CD32), and is potentially affected by its 131R/H polymorphism. Thus, panitumumab- mediated ADCC was more effective by neutrophils from FcgRIIa-131H homozygous individuals than from -131R individuals. ADCC induced by the IgG1 antibody zalutumumab was not affected by this polymorphism. In an experimental metastasis model in mice, both zalutumumab and panitumumab prevented establishment of metastases at low antibody concentrations which allowed the induction of ADCC but not the inhibition of signalling. Our results may implicate neutrophil- mediated ADCC in the in vivo mechanisms of action of EGF-R- directed antibodies, and suggest that heterogeneity in clinical responses due to the FcgRIIa-131R/H polymorphism can be expected for panitumumab.

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Transparent TiO2 nanotube electrodes via thin layer anodization: fabrication and use in electrochromic devices

In the present work, we describe an anodization process that is able to fully transform a thin Ti metal layer on a conductive glass into a TiO(2) nanotubular array. Under optimized conditions, nanotube electrodes can be obtained that are completely transparent and defect-free and allow electrochromic switching. These electrochromic electrodes show remarkable properties and can be directly integrated into devices.

The efficiency of nanotube formation on titanium anodized under voltage and current control in fluoride/glycerol electrolyte

The formation of nanotubes on titanium is compared for anodizing under controlled voltage and controlled current in a fluoride/glycerol electrolyte. Rutherford backscattering spectroscopy and nuclear reaction analysis are employed to determine the film compositions. Film morphologies are examined by electron microscopy. The findings reveal films of approximate composition TiO(2).0.15TiF(4) that probably also contain derivatives of glycerol. Controlled voltage conditions resulted in more uniform final nanotube dimensions, for a particular charge density, and the highest efficiency of film growth, with the charge of the titanium in the film representing ∼48% of the charge passed during anodizing. Under current control, the efficiency decreased from ∼40% to ∼23% with increase of the current density from 0.1 to 0.5 mA cm(-2). Further, the thickness of the barrier layer was sometimes enhanced under current control, possibly due to a non-uniform current distribution and consequently elevated local temperature.

Genetic dissection of glucocorticoid receptor function in the mouse brain

In the brain, glucocorticoids exert functions in neurogenesis, synaptic plasticity and behavioural responses, as well as in the control of hypothalamic-pituitary-adrenal axis activity. The generation of mice harbouring germline mutations that result either in loss or in gain of glucocorticoid receptor function provided a useful tool for understanding the role of glucocorticoids in the brain in vivo. The improvement of genomic technologies additionally allowed the establishment of mouse models with function-selective point mutations of the receptor as well as the generation of mice harbouring spatially and/or temporally restricted loss of glucocorticoid receptor, specifically within the brain. These models will provide the opportunity to better understand the mechanisms involved in glucocorticoid signalling within the nervous system.

Medical management of the failing Fontan

The Fontan operation accomplishes complete separation of systemic venous blood from pulmonary venous circulation in patients with single ventricle anatomy. Operative survival since the first description of the Fontan operation is excellent in the current era through modifications in surgical techniques, identification of patient-specific risk factors, and advances in postoperative care. Improved early outcomes have also resulted in a decline in late mortality for patients who have undergone staged palliation with the Fontan operation. As the number of late survivors from the Fontan operation increases, caregivers will be evermore faced with the challenge of recognizing and managing the patient with failing Fontan physiology. Even after excellent early results, patients with single ventricle lesions remain at risk of progressive ventricular dysfunction, dysrhythmias, progressive hypoxemia, elevated pulmonary vascular resistance, and protein-losing enteropathy, which can result in morbidities including but not limited to, myocardial failure, thromboembolism, and stroke. Consequently, continued long-term survival of patients who undergo the Fontan operation is dependent upon preservation of single ventricle function, avoidance of late complications, and, in the patient with a failing Fontan, recognition and treatment of the underlying pathophysiologic process that has resulted in Fontan failure.

A 1H-NMR thermometer suitable for cryoprobes

Most established NMR thermometers rely on temperature-dependent chemical shift differences measured from samples that are either neat or concentrated solutions (e.g. ethylene glycol, methanol). These are unsuitable for modern cryoprobes on account of strong radiation damping resulting from the high Q of the probe. Using perdeuterated methanol, we established a relationship between the chemical shift difference and temperature, and we show that this relationship is well fitted by a quadratic equation. The actual temperature within a sample tube in the probe was verified using a Pt-100 resistor.

Temperature dependence of exciton recombination in semiconducting single-wall carbon nanotubes

We study the excitonic recombination dynamics in an ensemble of (9,4) semiconducting single-wall carbon nanotubes by high-sensitivity time-resolved photoluminescence experiments. Measurements from cryogenic to room temperature allow us to identify two main contributions to the recombination dynamics. The initial fast decay is temperature independent and is attributed to the presence of small residual bundles that create external nonradiative relaxation channels. The slow component shows a strong temperature dependence and is dominated by nonradiative processes down to 40 K. We propose a quantitative phenomenological modeling of the variations of the integrated photoluminescence intensity over the whole temperature range. We show that the luminescence properties of carbon nanotubes at room temperature are not affected by the dark/bright excitonic state coupling.

Small omphalocele with umbilical evagination of the bladder: a distinct entity?

A neonatal case of umbilical evagination of the bladder combined with a small omphalocele is presented. This rare congenital malformation has previously been described in only three cases. Umbilical evagination can be understood as a disturbance of development of both the vitelline and allantoic ducts, resulting in a non-descended but otherwise normal bladder opening to the inferior margin of a small omphalocele. Diagnosis is made by clinical inspection and ultrasound. Since other malformations are not present, this entity may be regarded as a minor form of a lower midline defect with excellent prognosis.

A simple presurgical necrotizing enterocolitis-mortality scoring system

OBJECTIVE

To assess the relationship between early laboratory parameters, disease severity, type of management (surgical or conservative) and outcome in necrotizing enterocolitis (NEC).

STUDY DESIGN

Retrospective collection and analysis of data from infants treated in a single tertiary care center (1980 to 2002). Data were collected on disease severity (Bell stage), birth weight (BW), gestational age (GA) and pre-intervention laboratory parameters (leukocyte and platelet counts, hemoglobin, lactate, C-reactive protein).

RESULTS

Data from 128 infants were sufficient for analysis. Factors significantly associated with survival were Bell stage (P<0.05), lactate (P<0.05), BW and GA (P<0.01, P<0.001, respectively). From receiver operating characteristics curves, the highest predictive value resulted from a score with 0 to 8 points combining BW, Bell stage, lactate and platelet count (P<0.001). At a cutoff level of 4.5 sensitivity and specificity for predicting survival were 0.71 and 0.72, respectively.

CONCLUSION

Some single parameters were associated with poor outcome in NEC. Optimal risk stratification was achieved by combining several parameters in a score.

Osteochondrosis dissecans der Hüfte beim Erwachsenen - Differenzialdiagnostik freier Gelenkkörper - Fallbeschreibung

The causes of hip pain in adults can vary greatly. We present the case of a 44-year-old woman with recurrent hip pain over a period of years. Medical history and clinical examination did not provide any decisive information. The X-rays revealed a loose body in the cavity of the hip joint. The MRI scan made the following differential diagnosis plausible: osteochondrosis dissecans coxae, osteochondroma and chondromatosis. The final diagnosis of osteochondrosis dissecans coxae was confirmed by surgical dislocation of the hip as modified by Ganz and histological examination of the loose body. This case supports the importance of including rare lesions in the differential diagnostic work-up of joint pain. The advantages of the offset operation as modified by Ganz versus arthroscopy of the hip are outlined.

A novel liquid crystalline system for partial alignment of polar organic molecules

A new system for partial alignment of polar organic molecules to measure residual dipolar couplings in NMR consists of a 1:1 or a 2:1 mixture of water and DMSO including 3-13% n-alkylpentaethylene glycol as the surfactant. Temperature and concentration dependence of the alignment system are investigated and, as examples, the 13C,1H residual dipolar couplings for the amino acid methionine 1 and for an alpha-methylene-gamma-butyrolactone 2 have been obtained and are compared with those obtained from the alignment media consisting of n-alkylpentaethylene glycol, n-alkyl alcohol and water.