[Interdisciplinary surgery to the central skull base-current status]. / Interdisziplinäre Chirurgie der zentralen Schädelbasis ­ aktueller Stand.

BACKGROUND: The skull base is a surgically complex unit and is often only accessible via combined access routes. Newly developed surgical techniques using microsurgical visualization procedures and active instruments ("powered instruments") as well as multiport accesses enable new, less traumatic surgical corridors. This requires close interdisciplinary cooperation between ENT and neurosurgeons. Currently established access routes to the central skull base are systematized based on the authors' own clinical experience, and discussed in relation to the entity and the current study situation. MATERIALS AND METHODS: A retrospective, qualitative, and descriptive evaluation of the surgical reports of patients with pathologies of the central skull base who were jointly treated by neurosurgery and otorhinolaryngologic/head and neck surgery between 2006 and 2019 was performed. RESULTS: The surgical access routes to the central skull base can be categorized as so-called multiport access routes, partly also in combination, as follows: transnasal-transsphenoidal, subfrontal, subtemporal, transzygomatic, transpterygonal, transpetrous, translabyrinthine, and suboccipital. The choice of access route was based on the location and type of pathology, its inflammatory or space-occupying (benign or malignant tumor) nature, and the possibilities of functional preservation and complete removal. CONCLUSION: Due to the complexity of central skull base structures, the different tumor entities, and the required expertise of different medical specialties, surgery of the central skull base remains a challenge and should only be performed at special competence centers certified according to the criteria of the German Society of Skull Base Surgery.

[Cochlear nerve continuity preservation during retrosigmoid ablative osteotomy of the internal auditory canal for advanced vestibular schwannomas]. / Kontinuitätserhalt des Nervus cochlearis bei der retrosigmoidalen ablativen Osteotomie des inneren Gehörgangs bei fortgeschrittenen Vestibularisschwannomen.

The data of 86 patients with retrosigmoid microsurgical resection of vestibular schwannoma in tumor stage Koos II-IV were evaluated. In more than two thirds of the cases it was shown that the cochlear nerve followed the facial nerve, which is easily identified by electroneurography, in recurrent similar patterns in the region of the internal auditory canal. Starting from the fundus, this facilitated early identification and thus preservation of continuity of the cochlear nerve in the course of the internal auditory canal. This was of particular importance when safe functional preservation could not be guaranteed due to tumor size or formation despite intraoperative derivation of somatosenoric potentials, but when the possibility of subsequent hearing rehabilitation with a cochlear implant should be granted. Preoperative MRI sequences gave an indication of the possible nerve courses in some cases, but intraoperative imaging in the internal auditory canal was superior to MRI.

Ganglioneuroma suprarrenal gigante: Reporte de Un caso

Resumen El ganglioneuroma (Gn) es una neoplasia benigna, rara, derivada de la cresta neural, compuesta de células ganglionares maduras y células de Schwann. Solo una pequeña proporción de Gn se origina en la médula suprarrenal, siendo esta localización más frecuente en niños y adultos jóvenes. Hemos encontrado menos de 30 publicaciones reportadas en la literatura. Presentamos el caso de una paciente femenina de 37 años de edad, con dolor intermitente en fosa renal izquierda y flanco ipsilateral de 5 meses de evolución, sin otros síntomas acompañantes. Se realizó ecografía abdominal, tomografía axial computada (TAC) y resonancia magnética nuclear (RMI) abdomino pélvica, en las cuales se identificó formación expansiva solida, de 85 x 58 x 74 mm, de contornos definidos, adyacente a riñón izquierdo. Las características por imagen no permitieron descartar lesión benigna. Se realizó perfil hormonal completo para despistaje de funcionalidad. Dadas las características imagenológicas y el tamaño de la lesión, se decide tratamiento quirúrgico, considerando a feocromocitoma silente como principal diagnóstico presuntivo pre quirúrgico. La evolución postoperatoria fue excelente. Al examen microscópico, se observa proliferación nodular, de bordes delimitados, formado por células fusadas, con núcleos bipolares y citoplasmas elongados con aisladas células ganglionares. En la inmunomarcación presenta aisladas células ganglionares positivas para Cromogranina A y Sinaptofisina, proteína S100 positivo difuso, hallazgos consistentes con ganglioneuroma suprarrenal. El hallazgo de una masa suprarrenal en paciente joven, sin síntomas específicos, con características no sugestivas de adenoma, debe considerar el diagnostico de ganglioneuroma como parte de las lesiones incidentales adrenales y destacamos la importancia del diagnostico diferencial con feocromocitoma y carcinoma adrenal ya que comparten similares características imagenológicas. El tratamiento de elección es la resección quirúrgica completa, con pronóstico excelente en la mayoría de los casos.

Lepra histioide o de Wade: Presentación de un caso clínico / Wade histioid leprosy: A case report

La lepra histioide de Wade, es una forma clínico-histopatológica especial de lepra multibacilar, caracterizada por la presencia de tubérculos (lesiones papulosas o nodulares) correspondientes a lepromas formados por histiocitos de morfología fusiforme. La misma es una variante infrecuente de lepra lepromatosa, que se desarrolla generalmente como recaída, en pacientes que recibieron monoterapia con dapsona, aunque se reportó su presentación de novo. En el presente trabajo, se comunica el caso clínico de una paciente de sexo femenino de 45 años de edad, con diagnóstico tardío de lepra histioide. Además, se examinan las características principales de esta forma particular de expresión de la lepra, sus diferencias con la forma clásica de presentación, los diagnósticos diferenciales que deben considerarse y la importancia de tener a esta patología entre las sospechas diagnósticas, para comenzar el tratamiento adecuado y evitar su propagación.

Wade's hystioid leprosy is a special clinical-pathological form of multibacillary leprosy, characterized by papular and nodular lepromas that consist of spindle histiocytes. It is a variant of lepromatous leprosy. Most of the cases have been related to dapsone resistance in the context of longterm monotherapy. De novo cases, not associated with previous anti-leprosy treatment, have been less frequently reported. This article presents the case of 45 years old female, with late diagnosis of histoid leprosy. There will be explained the main features of this particular form of leprosy, its differences with the classic presentation, the differential diagnoses to be considered, and the importance of having this pathology among diagnostic suspicions to begin adecuate treatment.

EPSPS variability, gene expression, and enzymatic activity in glyphosate-resistant biotypes of Digitaria insularis.

Weed resistance to herbicides is a natural phenomenon that exerts selection on individuals in a population. In Brazil, glyphosate resistance was recently detected in Digitaria insularis. The objective of this study was to elucidate mechanisms of weed resistance in this plant, including genetic variability, allelism, amino acid substitutions, gene expression, and enzymatic activity levels. Most of these have not previously been studied in this species. D. insularis DNA sequences were used to analyze genetic variability. cDNA from resistant and susceptible plants was used to identify mutations, alleles, and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) expression, using real-time quantitative reverse transcription-polymerase chain reaction. In addition, EPSPS activity was measured. We found a decrease in genetic variability between populations related to glyphosate application. Substitutions from proline to threonine and tyrosine to cysteine led to a decrease in EPSPS affinity for the glyphosate. In addition, the EPSPS enzymatic activity was slightly higher in resistant plants, whereas EPSPS gene expression was almost identical in both biotypes, suggesting feedback regulation at different levels. To conclude, our results suggest new molecular mechanisms used by D. insularis to increase glyphosate resistance.

Impact of gas formation kinetics on dough development and bread quality.

The baking performance and gas retention capacity of wheat dough depends on production rate and total volume of CO2 during fermentation. This study aims to examine the effect of the CO2 formation kinetics and the gas volume fraction on the structural integrity of wheat dough and the resulting bread quality. The gas release characteristics were evaluated using a rheofermentometer with varied concentrations of compressed yeast and instant dry yeast (CY and IDY respectively). For this purpose, the maximum CO2 formation rate was calculated through the derivation of hydrostatic pressure curves measured in the rheofermentometer. For CY, the time when gas escapes the dough matrix (Tx, time of porosity) as well as the corresponding gas volume depended on the gas formation rate, whereas the gas retention capacity of wheat dough leavened with IDY was not affected by the CO2 formation rate. Although the dough leavened with IDY showed improved extensibility during fermentation, the specific bread volume was 21% below that of the samples leavened with CY. These results indicate that an increase in the maximum gas formation rate considerably affects the structural integrity of the dough matrix. Because of the reduction of the loaf volume, the effect is reinforced by the application of IDY.

The contribution of glutathione to the destabilizing effect of yeast on wheat dough.

Any factor which impairs the development of the gluten network affects the gas retention capacity and the overall baking performance. This study aimed to examine why rising yeast concentrations (Saccharomyces cerevisiae) decrease the dough elasticity in an asymptotic manner. Since in 27 commercial fresh and dry yeasts up to 81 mg glutathione (GSH) per 1g dry sample were found. Through the addition of reduced GSH in dough without yeast, the extent of dough weakening was analysed. Indeed rheological measurements confirmed that yeast-equivalent levels of GSH had a softening effect and during 3h fermentation the weakening coefficient increased from 0.3% to 20.4% in a Rheofermentometer. The present results indicate that free -SH compounds, as represented by GSH, considerably contribute to the softening of dough through dead yeast cells.

Glioblastoma tumor initiating cells: therapeutic strategies targeting apoptosis and microRNA pathways.

Glioblastoma (GBM) is a highly malignant primary brain tumor known for its invasiveness and aggressive resistance to standard treatment. It is currently the most common primary brain tumor which is associated with a high mortality rate. Tumor initiating cells (TICs) are a subpopulation of GBM stem cells which are capable of self-renewal and apoptotic resistance, and are thought to account for GBMs aggressive nature. Recent efforts have focused on therapies which target key intracellular apoptotic pathways which may confer tumor resistance, such as Akt, p53, Bcl-2 family proteins, caspase family proteases, and more recently microRNAs. Research into microRNA's role in GBM has shown that microRNAs play a key regulatory role in the GBM apoptotic pathway, making it a potential therapeutic target. In this review we summarized the molecular mechanisms involved in the signaling pathways of human GBM TIC apoptosis and microRNAs, the contemporary treatments involving different members of the signaling cascade, and the future direction of GBM treatment strategies.

Brain tumour surgery in the vicinity of short-term memory representation--results of neuronavigation using fMRI images.

OBJECTIVE: Functional information concerning the surrounding brain is mandatory for a good clinical outcome in brain tumour surgery. The value of fMRI to detect the motorcortex and Broca's area is widely accepted today. If an appropriate paradigm is used, short-term memory areas can be visualized as well. Obviously this information must be integrated into cranial neuronavigation for an appropriate intra-operative use. We report our first experiences with the direct integration of short-term memory fMRI into cranial neuronavigation. METHOD: From January 2001 to March 2002 14 patients were operated on for intracranial tumours with short-term memory fMRI imaging, using the "two-back-paradigm". Both pre- and postoperatively, the short-term memory of all patients was tested additionally by a standardized test battery including 16 different verbal and visuo-spatial items. RESULTS: In all 14 patients the general level of working memory capacity was preserved after surgery. The visuo-spatial performance was kept unchanged or deteriorated slightly, the alertness slightly worsened as well, but we found an improvement in verbal test items. CONCLUSION: The two-back paradigm is able to visualize verbal memory tasks in fMRI. For visuo-spatial items, a new paradigm has to be designed. In contrast to deep seated brain lesions, focal cortical impairments do not lead to obvious and serious memory deficits. Therefore, the aim of gross total tumour removal has to be balanced against the aim of preservation of short-term memory fields. Nevertheless, the knowledge of the localization of cortical short-term memory fields may combine both aims during navigated brain tumour surgery, thus preserving the patient with a better quality of life.

Soil microbial community response to land use change in an agricultural landscape of western Kenya.

Tropical agroecosystems are subject to degradation processes such as losses in soil carbon, nutrient depletion, and reduced water holding capacity that occur rapidly resulting in a reduction in soil fertility that can be difficult to reverse. In this research, a polyphasic methodology has been used to investigate changes in microbial community structure and function in a series of tropical soils in western Kenya. These soils have different land usage with both wooded and agricultural soils at Kakamega and Ochinga, whereas at Ochinga, Leuro, Teso, and Ugunja a replicated field experiment compared traditional continuous maize cropping against an improved N-fixing fallow system. For all sites, principal component analysis of 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles revealed that soil type was the key determinant of total bacterial community structure, with secondary variation found between wooded and agricultural soils. Similarly, phospholipid fatty acid (PLFA) analysis also separated wooded from agricultural soils, primarily on the basis of higher abundance of monounsaturated fatty acids, anteiso- and iso-branched fatty acids, and methyl-branched fatty acids in the wooded soils. At Kakamega and Ochinga wooded soils had between five 5 and 10-fold higher levels of soil carbon and microbial biomass carbon than agricultural soils from the same location, whereas total enzyme activities were also lower in the agricultural sites. Soils with woody vegetation had a lower percentage of phosphatase activity and higher cellulase and chitinase activities than the agricultural soils. BIOLOG analysis showed woodland soils to have the greatest substrate diversity. Throughout the study the two functional indicators (enzyme activity and BIOLOG), however, showed lower specificity with respect to soil type and land usage than did the compositional indicators (DGGE and PLFA). In the field experiment comparing two types of maize cropping, both the maize yields and total microbial biomass were found to increase with the fallow system. Moreover, 16S rRNA gene and PLFA analyses revealed shifts in the total microbial community in response to the different management regimes, indicating that deliberate management of soils can have considerable impact on microbial community structure and function in tropical soils.

Percutaneous transarticular atlantoaxial screw fixation using a cannulated screw system and image guidance.

In 2000 a cannulated screw stabilization system for posterior cervical instrumentation was introduced in our department for use in complex cervical fixation procedures. A special feature of the system is the use of thin Kirschner wires for drilling the screw paths and then placing the self-drilling, cannulated screws securely over the wires. Percutaneous application of C1-C2 transarticular screws is possible through tubes. An optional "atlas-claw" provides additional stability in cases of C1-C2 stabilization. 17 patients (10 female, 7 male, mean age 60 years) with complex cervical disorders and instability of different origin were stabilized using the Neon System (Ulrich Co., Ulm, Germany). Pathology included atlantoaxial instability based on rheumatoid arthritis (n = 12), odontoid fracture (n = 4) and os odontoideum mobile (n = 1). Computed navigation (STN 4.0, Zeiss or vector vision spine, brain lab) was used in 14 cases. Transarticular C1-C2 screw fixation was performed in 14 cases (4 patients with direct C1 massa lateralis screw fixation), craniocervical fixation (C0-C2/C3) was done in 3 patients. Percutaneous application of the C1-C2 screws was used in 7 patients. Atlas claws were applied in 8 patients. There was one medial perforation of a C2 pedicle wall and one malposition of the screw in C2 without reaching the lateral mass of C1. After a mean follow-up of 9 months there were no hardware failures and stable fusion in those cases followed after 12 months or more. Clinical results were excellent or good in 14/16 patients. Cannulated screws are an effective alternative in complex stabilization procedures of the cervical spine. The presented system is technically comfortable and allows safe percutaneous screw application as well as inclusion of computed navigation with high accuracy.

Bounded-depth threshold circuits for computer-assisted CT image classification.

We present a stochastic algorithm that computes threshold circuits designed to discriminate between two classes of computed tomography (CT) images. The algorithm employs a partition of training examples into several classes according to the average grey scale value of images. For each class, a sub-circuit is computed, where the first layer of the sub-circuit is calculated by a new combination of the Perceptron algorithm with a special type of simulated annealing. The algorithm is evaluated for the case of liver tissue classification. A depth-five threshold circuit (with pre-processing: depth-seven) is calculated from 400 positive (abnormal findings) and 400 negative (normal liver tissue) examples. The examples are of size n=14,161 (119 x 119) with an 8 bit grey scale. On test sets of 100 positive and 100 negative examples (all different from the learning set) we obtain a correct classification close to 99%. The total sequential run-time to compute a depth-five circuit is about 75h up to 230h on a SUN Ultra 5/360 workstation, depending on the width of the threshold circuit at depth-three. In our computational experiments, the depth-five circuits were calculated from three simultaneous runs for depth-four circuits. The classification of a single image is performed within a few seconds.

Logarithmic simulated annealing for X-ray diagnosis.

We present a new stochastic learning algorithm and first results of computational experiments on fragments of liver CT images. The algorithm is designed to compute a depth-three threshold circuit, where the first layer is calculated by an extension of the Perceptron algorithm by a special type of simulated annealing. The fragments of CT images are of size 119x119 with eight bit grey levels. From 348 positive (focal liver tumours) and 348 negative examples a number of hypotheses of the type w(1)x(1)+. . .;+w(n)x(n)>/=theta were calculated for n=14161. The threshold functions at levels two and three were determined by computational experiments. The circuit was tested on various sets of 50+50 additional positive and negative examples. For depth-three circuits, we obtained a correct classification of about 97%. The input to the algorithm is derived from the DICOM standard representation of CT images. The simulated annealing procedure employs a logarithmic cooling schedule c(k)=Gamma/ln(k+2), where Gamma is a parameter that depends on the underlying configuration space. In our experiments, the parameter Gamma is chosen according to estimations of the maximum escape depth from local minima of the associated energy landscape.

Flexible versus rigid endoscopes for outpatient hysteroscopy: a prospective randomized clinical trial.

To evaluate patient acceptance, optical properties and the clinical feasibility of flexible compared with rigid hysteroscopes, 142 patients undergoing outpatient hysteroscopy were included in a prospective, randomized clinical trial. The flexible hysteroscope was used in 70 patients, and the rigid instrument in 72. At different stages of the hysteroscopy the level of pain experienced by the women was assessed using a 10 cm visual analogue scale. Optical properties characterized by the parameters intrauterine visibility, hysteroscopic view and diagnostic accuracy were ranked by the surgeons using a 5-point scale (1 = excellent to 5 = insufficient), and duration of the hysteroscopy was measured. Hysteroscopy was successful in 87.5 and 100% of patients in the flexible and rigid groups respectively. With the use of rigid telescopes, discomfort at introduction and during the hysteroscopy was significantly greater (median 1.7 versus 0.7, P = 0.003; 3.1 versus 1.2, P < 0.001 respectively), but optical properties were judged to be far superior (P < 0.001 for all three comparisons) and procedure time was significantly shorter (median 70 versus 120 s, P = 0.003). In conclusion, outpatient hysteroscopy seems to be less painful when using flexible telescopes. However, rigid hysteroscopes provide superior optical qualities and permit a more rapid performance with higher success rates at much lower cost.

Impact of maternal anthropometry and smoking on neonatal birth weight.

The purpose of this study was to determine the effect of maternal pre-pregnancy body mass index (BMI) and maternal smoking habits on neonatal birth weight. We reviewed 10,240 normal singleton term pregnancies between 1985 and 1995 at the University Department of Obstetrics and Gynecology, Vienna. Birth weights of infants of overweight smokers were greater than those of smokers in general and similar to birth weights of nonsmokers, but smoking did have a fetal growth-retarding effect in overweight smoking mothers. Infants of underweight mothers who increased their daily cigarette consumption during pregnancy had significantly lowest birth weight. Our results suggest that the negative effects of smoking during pregnancy cannot be mitigated by a higher pre-pregnancy BMI and/or an improved weight gain during pregnancy. Especially the infants of underweight mothers benefit from their mothers' decision to cease smoking.

[Technique and results of laparoscopic conservative organ-preserving myoma enucleation]. / Technik und Resultate der laparoskopisch konservativen, organerhaltenden Myomenukleation.

Myoma is one of the most common benign diseases of the female genital tract. The surgical management of this entity has been altered over the last years from complete hysterectomy to conservative enucleation of the myomas. We retrospectively compared our data concerning laparoscopic or open myomectomies. Over a period of 2 years, we operated 207 myomas in 102 patients. Of this collective, 69 (67.6%) were operated on laparoscopically and 33 (32.4%) via an open approach. In both groups, the median number of myomas was 2 (1-7). The mean diameter of the largest myoma was 5.1 +/- 2.4 cm (laparoscopy) and 6.2 +/- 2.6 cm (laparotomy), respectively. The additive diameter of myomas was 7.7 +/- 5.1 cm (laparoscopy) and 9.8 +/- 4.1 cm (laparotomy), respectively. There was no relevant difference between the groups in terms of operating time and blood loss. Four (3.9%) laparoscopies had to be converted to an open approach. In three cases (2.9%) a laparoscopically assisted enucleation had to be performed, requiring a mini-laparotomy 4 to 5 cm in length. We encountered no severe complications. Given appropriate indication, laparoscopic myomectomy is an easy-to-perform and minimally invasive technique with a low complication rate.

Membrane properties of archaeal macrocyclic diether phospholipids.

Several biophysical properties of four synthetic archaeal phospholipids [one polyprenyl macrocyclic lipid A and three polyprenyl double-chain lipids (B, C, D) bearing zero, one or four double bonds in each chain] were studied using differential scanning calorimetry, electron and optical microscopies, stopped-flow/light scattering and solid-state 2H-NMR techniques. These phospholipids gave a variety of self-organized structures in water, in particular vesicles and tubules. These assemblies change in response to simple thermal convection. Some specific membrane properties of these archaeal phospholipids were observed: They are in a liquid-crystalline state over a wide temperature range; the dynamics of their polyprenyl chains is higher than that of n-acyl chains; the water permeability of the membranes is lower than that of n-acyl phospholipid membranes. It was also found that macrocyclization remarkably improves the barrier properties to water and the membrane stability. This may be related to the adaptation of Methanococcus jannaschii to the extreme conditions of the deep-sea hydrothermal vents.

Proanthocyanidins and human health: systemic effects and local effects in the gut.

Proanthocyanidins share common properties with other polyphenols, in particular their reducing capacity and ability to chelate metal ions. However, their polymeric nature clearly makes them different. They have a high affinity for proteins and their absorption through the gut barrier is likely limited to the molecules of low polymerization degree and to the metabolites formed by the colonic microflora, as suggested by in vitro experiments. The nutritional significance of proanthocyanidins is discussed in relation to their physico-chemical properties and bioavailability.