An update on the surgical treatment of temporal bone paraganglioma

In 1982, Fisch described his results for the surgical treatment of 74 paragangliomas of the temporal bone, 5 years after his description of the infratemporal fossa approaches (types A and B). This study reviews the subsequent experience of the Department of Otolaryngology-Head and Neck Surgery of the University of Zürich with more than 136 surgically treated cases of paraganglioma of the temporal bone and discusses our current therapy 20 years after the initial description. One hundred nineteen (90%) of the patients had advanced tumors (Fisch class C or C+D), and 81 (68%) had intracranial extension. Total tumor excision was possible in 109 (82%) patients. Subtotal excision was performed in 22 (17%) patients, 21 of whom had intradural tumor invasion. In these cases, the resection was limited not by actual tumor size but by the degree of intracranial intradural tumor extension. Partial tumor excision was undertaken in only 1 patient with a C4De2Di2 tumor. The success rate in preservation of function of the lower cranial nerves was encouraging. Of the 69 patients whose facial nerve status was followed post-operatively, 81% maintained Fisch grade 76 to 100% (House-Brackman grades I and II). Analysis of follow-up data ranging from 2 to 11 years demonstrated 98% disease-free survival when total tumor extirpation was possible. In the patients who underwent subtotal or partial surgical resection there has been no subsequent tumor growth detected by either clinical or neuroradiological evaluation. We have confirmed after more than 20 years of experience that the infratemporal fossa approaches are a safe, highly effective means of surgical management of paragangliomas of the temporal bone, allowing eradication or arrest of disease with minimal morbidity. Limited intradural surgical resection in cases of very extensive tumors can greatly benefit patients for whom complete excision is not an option.

A reproducible porcine model of acute liver failure induced by intrajejunal acetaminophen administration

BACKGROUND AND AIMS

Severe intoxication following acetaminophen overdose is the most common cause of acute liver failure (ALF) in many Western European and North American countries. A reproducible large animal model of acetaminophen intoxication has not been successfully evaluated previously.

METHODS

Eight male pigs underwent acetaminophen intoxication receiving an initial enteric bolus of 250 mg/kg body weight acetaminophen followed by an acetaminophen plasma level (300-450 mg/l) adapted enteric maintenance dose of 1,000-3,000 mg/h to the onset of ALF (prothrombin time value <30%). Vital and ventilation parameters were continuously recorded until death. Saline, hydroxyethyl starch, fresh frozen plasma and erythrocyte units were used for volume substitution, and norepinephrine to prevent severe hypotension.

RESULTS

All animals developed ALF after 25 ± 3 h, which was confirmed by laboratory values, the clinical course and histological examinations. All animals died due to ALF after a further 21 ± 5 h, precipitated by cerebral edema.

CONCLUSIONS

Using an initial enteric acetaminophen bolus, followed by body weight-adapted acetaminophen plasma level intoxication, it was possible to establish a reproducible, clinically relevant porcine model which may be used for the investigation of novel therapeutic approaches in this life-threatening condition.

Bimodal pollination system of the bromeliad Aechmea nudicaulis involving hummingbirds and bees

In order to compare the effectiveness of birds and insects as pollinators, we studied the floral biology of the bromeliad Aechmea nudicaulis (L.) Grisebach in the biome of the Atlantic rain forest, southern Brazil. On Santa Catarina Island, flowering extends from mid-September to the end of December, with diurnal anthesis. The reproductive system is obligatory xenogamy, thus pollinator-dependent. Flowers secrete 31.84 μl of nectar per day, with a mean sugar concentration of 23.2%. Highest nectar volume and sugar concentration occur at the beginning of anthesis. Most floral traits are characteristic for ornithophily, and nectar production appears to be adapted to the energy demand of hummingbirds. Continued secretion of the sucrose-dominated nectar attracts and binds visitors to inflorescences, strengthening trapline foraging behaviour. Experiments assessing seed set after single flower visits were performed with the most frequent visitors, revealing the hummingbird Thalurania glaucopis as the most effective pollen vector. In addition, bees are also functional pollinators, as substantiated by their high visitation frequency. We conclude that this pollination system is bimodal. Thus, there is redundancy in the pollination service provided by birds and bees, granting a high probability of successful reproduction in Ae. nudicaulis.

[The concept of chronic disease in the palliative treatment of oncologic patients: current Swiss data and insights in the context of breast and ovarian cancer]

In the last years, incurable oncologic diseases have become increasingly viewed as chronic disease processes. In order to evaluate the treatment course of a chronic disease and to demonstrate whether the concept of a palliative oncologic situation as a chronic disease can be translated into practice, it is essential to give an overview of the entire course of the disease (i.e. from the first diagnosis of recurrence/metastases to death). There are only few reports regarding this approach in the international literature. We present Swiss long-term data (1990-2007) for breast and ovarian cancer and demonstrate drawbacks and opportunities of an exact retrospective data collection and analysis. When an incurable disease which requires periodic therapy cycles to control progressive course and symptoms is increasingly treated with a strategy that permits stabilization and uses regimens that have limited cumulative toxicity with particular consideration of quality of life, then the requirements of a chronic disease management have been fulfilled.

The tumour-suppressive miR-29a/b1 cluster is regulated by CEBPA and blocked in human AML

BACKGROUND

CCAAT/enhancer-binding protein-alpha (CEBPA) is crucial for normal granulopoiesis and is frequently disrupted in acute myeloid leukaemia (AML). Increasing evidence suggests that CEBPA exerts its effects, in parts, by regulating specific microRNAs (miRNAs), as previously shown for miR-223. The aim of this study was to investigate the genome-wide pattern of miRNAs regulated by CEBPA in myeloid cells.

METHODS

In Kasumi-1 cells, conditionally expressing CEBPA, we assessed the expression of 470 human miRNAs by microarray analysis. We further investigated the microarray results by qRT-PCR, luciferase reporter assays, and chromatin immunoprecipitation assays.

RESULTS

In all, 18 miRNAs were more than two-fold suppressed or induced after CEBPA restoration. Among these 18 miRNAs, we focused on CEBPA-mediated regulation of the tumour-suppressive miR-29b. We observed that miR-29b is suppressed in AML patients with impaired CEBPA function or loss of chromosome 7q. We found that CEBPA selectively regulates miR-29b expression on its miR-29a/b1 locus on chromosome 7q32.3, whereas miR-29b2/c on chromosome 1q32.2 is not affected.

CONCLUSION

This study reports the activation of the tumour-suppressive miR-29b by the haematopoietic key transcription factor CEBPA. Our data provide a rationale for miR-29b suppression in AML patients with loss of chromosome 7q or CEBPA deficiency.

VHL inactivation is an important pathway for the development of malignant sporadic pancreatic endocrine tumors

A small subset of familial pancreatic endocrine tumors (PET) arises in patients with von Hippel-Lindau syndrome and these tumors may have an adverse outcome compared to other familial PET. Sporadic PET rarely harbors somatic VHL mutations, but the chromosomal location of the VHL gene is frequently deleted in sporadic PET. A subset of sporadic PET shows active hypoxia signals on mRNA and protein level. To identify the frequency of functionally relevant VHL inactivation in sporadic PET and to examine a possible prognostic significance we correlated epigenetic and genetic VHL alterations with hypoxia signals. VHL mutations were absent in all 37 PETs examined. In 2 out of 35 informative PET (6%) methylation of the VHL promoter region was detected and VHL deletion by fluorescence in situ hybridization was found in 14 out of 79 PET (18%). Hypoxia inducible factor 1alpha (HIF1-alpha), carbonic anhydrase 9 (CA-9), and glucose transporter 1 (GLUT-1) protein was expressed in 19, 27, and 30% of the 152 PETs examined. Protein expression of the HIF1-alpha downstream target CA-9 correlated significantly with the expression of CA-9 RNA (P<0.001), VHL RNA (P<0.05), and VHL deletion (P<0.001) as well as with HIF1-alpha (P<0.005) and GLUT-1 immunohistochemistry (P<0.001). These PET with VHL alterations and signs of hypoxia signalling were characterized by a significantly shortened disease-free survival. We conclude that VHL gene impairment by promoter methylation and VHL deletion in nearly 25% of PET leads to the activation of the HIF-pathway. Our data suggest that VHL inactivation and consecutive hypoxia signals may be a mechanism for the development of sporadic PET with an adverse outcome.

Ambient temperature impacts on pH of exhaled breath condensate

BACKGROUND AND OBJECTIVE

Analysis of exhaled breath condensate (EBC) pH is a non-invasive method to study airway inflammation. Low pH is correlated with inflammatory diseases like asthma and COPD. The aim of this study was to assess the influence of measurement temperature on pH values of EBC.

METHODS

EBC was collected using the RTube in 10 healthy non-smoking controls, 10 smokers before and after cigarette smoking, 10 stable COPD patients and 10 patients with exacerbated COPD. pH was determined directly after degassing at temperatures of 23 degrees C and 37 degrees C.

RESULTS

When comparing all groups pH was significantly (P = 0.0002) higher (mean +/- SD 7.88 +/- 0.92) at 37 degrees C as compared with 23 degrees C (7.44 +/- 0.90). Specifically, at 23 degrees C pH was significantly lower in the group of exacerbated COPD (6.78 +/- 1.27) and healthy non-smoking controls (8.04 +/- 0.39). In contrast, subgroup analysis of values assessed at 37 degrees C did not display significant differences.

CONCLUSIONS

Our data indicate a considerable influence of temperature on pH values in EBC. Thus the temperature at which pH measurements in EBC studies are performed should be declared.