Transitional cell carcinoma (TCC) may mimic renal cell carcinoma (RCC) when it develops in a similar location, therefore, differentiation with imaging techniques might be challenging. Preoperative differentiation may have a significant... more
Transitional cell carcinoma (TCC) may mimic renal cell carcinoma (RCC) when it develops in a similar location, therefore, differentiation with imaging techniques might be challenging. Preoperative differentiation may have a significant role indicating the type of surgical treatment (nephrectomy vs. ureteronephrectomy). To retrospectively analyze the differences in the contrast enhancement of TCC and RCC. Images of 20 RCC and 12 TCC (mean ages, 62.3 ± 14.1 and 67.4 ± 12.0 years, respectively) were analyzed from patients who underwent multiphase computed tomography (CT) examinations following 1.5 mL/kg non-ionic contrast agent administration. Unenhanced corticomedullary (30-45 s), nephrographic (70-90 s), and excretory (300-480 s) phases were imaged. The attenuation characteristics of RCC and TCC were compared to the attenuation of the normal renal cortex. Significant differences were found in the attenuation ratios between RCC or TCC in the corticomedullary (P = 0.040) and nephrographic (P = 0.004) phases using three regions of interest (ROIs) of 10 mm(2) size. If measuring ROIs comprising the complete tumor lesion instead of three small ROIs, no significant difference was observed in the attenuation ratios between RCC in TCC in any phases. Our study reports significant attenuation differences between RCC and TCC in the corticomedullary and nephrographic phases by multiphase CT. The findings underscore the importance of multiphase CT in the differentiation of these two different entities. Using multiple small (three) ROIs is more accurate than measuring the whole tumor attenuation.
Conventional clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) have different behavioral characteristics and clinical management strategies (nephrectomy vs. nephron-sparing surgery). Our aim was to... more
Conventional clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) have different behavioral characteristics and clinical management strategies (nephrectomy vs. nephron-sparing surgery). Our aim was to retrospectively evaluate the contrast enhancement pattern of ccRCC and pRCC and evaluate its possible diagnostic role for preoperative differentiation using a standardized protocol. Quadriphasic multidetector computed tomography (CT) images (unenhanced, corticomedullary, nephrographic, and excretory phases) of 19 patients with 20 ccRCC and 14 patients with 15 pRCC lesions (mean ages, 62.3±14.1 and 61.4±13.7 years, respectively) were reviewed retrospectively. The attenuation characteristics were compared with the attenuation of the normal renal cortex using either multiple 10 mm2 regions of interest or whole tumor attenuation measurements. The degree of contrast enhancement was also compared. Univariate analysis revealed that ccRCC lesions showed higher mean attenuation values on the corticomedullary and nephrographic phases compared with pRCC masses (P < 0.05) using both measurement techniques. The findings underscore the importance of multiphase CT in the differentiation of these two subtypes of RCC using standard assessment techniques. The measurement of the degree of enhancement on contrast-enhanced multidetector CT may be a simple and useful method to radiologically differentiate between the two histological types of RCC.
Perineuronal matrix is an extracellular protein scaffold to shape neuronal responsiveness and survival. Whilst perineuronal nets engulf the somatodendritic axis of neurons, axonal coats are focal extracellular protein aggregates... more
Perineuronal matrix is an extracellular protein scaffold to shape neuronal responsiveness and survival. Whilst perineuronal nets engulf the somatodendritic axis of neurons, axonal coats are focal extracellular protein aggregates surrounding individual synapses. Here, we addressed the chemical identity and subcellular localization of both perineuronal and perisynaptic matrices in the human hippocampus, whose neuronal circuitry is progressively compromised in Alzheimer's disease. We hypothesized that (1) the cellular expression sites of chondroitin sulphate proteoglycan-containing extracellular matrix associate with specific neuronal identities, reflecting network dynamics, and (2) the regional distribution and molecular composition of axonal coats must withstand Alzheimer's disease-related modifications to protect functional synapses. We show by epitope-specific antibodies that the perineuronal protomap of the human hippocampus is distinct from other mammals since pyramidal cells but not calretinin(+) and calbindin(+) interneurons, neurochemically classified as novel neuronal subtypes, lack perineuronal nets. We find that cartilage link protein-1 and brevican-containing matrices form isolated perisynaptic coats, engulfing both inhibitory and excitatory terminals in the dentate gyrus and entorhinal cortex. Ultrastructural analysis revealed that presynaptic neurons contribute components of perisynaptic coats via axonal transport. We demonstrate, by combining biochemical profiling and neuroanatomy in Alzheimer's patients and transgenic (APdE9) mice, the preserved turnover and distribution of axonal coats around functional synapses along dendrite segments containing hyperphosphorylated tau and in amyloid-β-laden hippocampal microdomains. We conclude that the presynapse-driven formation of axonal coats is a candidate mechanism to maintain synapse integrity under neurodegenerative conditions.
Extracellular matrix molecules take part in functional isolation and stabilization of neuronal compartments but form a vivid interface between neuronal elements at the same time. Previous studies have shown that the accumulation of... more
Extracellular matrix molecules take part in functional isolation and stabilization of neuronal compartments but form a vivid interface between neuronal elements at the same time. Previous studies have shown that the accumulation of extracellular matrix, especially its typical phenotypic form, termed perineuronal nets, correlates not only with the functional properties of the single neuron but also with the functional properties of the whole brain area. In contrast to recent advances in investigating neocortex, the present study mapped the occurrence and phenotypic appearance of aggrecan-based matrix accumulation throughout the rat thalamus. Results showed that divisions of thalamus that relay information to cortical fields known rather for their plastic properties exibit a poor matrix immunoreactivity, whereas matrix accumulation is more enhanced in nuclei connected to primary cortical regions. In addition to perineuronal nets, extracellular matrix condensed in another peculiar form, in 2-5-μm, large, round or oval structures, as described by Brückner et al. ([ 2008] Neuroscience 151:489-504) as axonal coats (ACs). Multiple labelling experiments showed that specific excitatory afferents were not ensheathed with these structures. At the same time, inhibitory endings were occasionally enwrapped in ACs. Electron microscopic analysis showed that aggrecan-immunoreactive profiles were present mostly around inhibitory terminals but also in all neuronal compartments. We suggest that aggrecan-based extracellular matrix is formed by both pre- and postsynaptic elements and is preferably associated with inhibitory terminals in the extracellular space.
Extracellular matrix is a key component of most connective tissues. For decades, the presence of this chemically heterogeneous interface has been largely ignored or even denied in the central nervous system. It was not until the end of... more
Extracellular matrix is a key component of most connective tissues. For decades, the presence of this chemically heterogeneous interface has been largely ignored or even denied in the central nervous system. It was not until the end of the last century that scientists turned their attention to this enigmatic substance and unravelled its versatile roles in the developing as well as the adult nervous system. The aim of the authors was to characterize different parts of the human central nervous system: the hippocampus, the lateral geniculate nucleus and the spinal cord. In addition they looked for connections between brain plasticity and extracellular matrix indifferent animal models. The authors used two perfusion fixed human brain and spinal cord samples, 23 further human brain samples for disease-related investigations, 16 adult rat brains and 18 chicken brains of hatchlings, 13 days or three months of age. They visualized the extracellular matrix via lectin- and immunohistochemistry. It was demonstrated that the human central nervous system shows a bewildering phenotypic versatility in its various parts. The human spinal cord harbours perineuronal nets around long-range projection neurons whilst peri-synaptic coats are enriched in the dorsal horn. Periaxonal coats protect functional synapses in neurodegeneration. In the rat thalamus, perineuronal matrix is enriched in less plastic territories and develops in accordance with its linked cortical region. In the chicken, perineuronal matrix is well established already at birth and its further development is not functionally dependent. In human, the perineuronal matrix shows a large diversity depending on regional distribution and function. The authors argue that the development and differentiation of extracellular matrix is strongly linked to those of neurons. This observation was based on findings in the domestic chick which exhibits an immediate maturity after hatching as well as on observations in rat thalamic nuclei which reflect the plasticity of their corresponding cortical fields.
The amyloid precursor protein is essential for proper neuronal function but an imbalance in processing or metabolism or its overexpression lead to severe malfunction of the brain. The present study focused on dendritic morphology of... more
The amyloid precursor protein is essential for proper neuronal function but an imbalance in processing or metabolism or its overexpression lead to severe malfunction of the brain. The present study focused on dendritic morphology of hippocampal neurons in mice overexpressing the wild-type human amyloid precursor protein (hAPP). In addition, we examined whether enhanced physical activity may affect hAPP-related morphological changes. Overexpression of hAPP resulted in significant enlargement of dendrites, especially within the basal dendritic field but had no effect on spine density. Enhanced physical activity only moderately potentiated hAPP induced changes in dendritic size. Physical activity dependent increases in spine density were, however, augmented by hAPP overexpression. The results suggest that enhanced levels of wild-type hAPP do not result in degenerative changes of neuronal morphology, but rather promote dendritic growth.
In the vertebrate nervous system, the Ca(2+)-binding proteins parvalbumin, calbindin and calretinin have been extensively used to elaborate the molecular diversity of neuronal subtypes. Secretagogin is a phylogenetically conserved... more
In the vertebrate nervous system, the Ca(2+)-binding proteins parvalbumin, calbindin and calretinin have been extensively used to elaborate the molecular diversity of neuronal subtypes. Secretagogin is a phylogenetically conserved Ca(2+)-binding protein, which marks neuronal populations largely distinct from other Ca(2+)-binding proteins in mammals. Whether secretagogin is expressed in nonmammalian vertebrates, particularly in birds, and, if so, with a brain cytoarchitectonic design different from that of mammals is unknown. Here, we show that secretagogin is already present in the hatchlings' brain with continued presence into adulthood. Secretagogin-immunoreactive neurons primarily accumulate in the olfactory bulb, septum, subpallial amygdala, hippocampus, hypothalamus, habenular nuclei and deep layers of the optic tectum of adult domestic chicks (Gallus domesticus). In the olfactory bulb, secretagogin labels periglomerular neurons as well as a cell continuum ascending dorsome...
In volume-rendering applications the input data is usually acquired by measuring some kind of phys-ical property. The accuracy of the measurement strongly influences the quality of images produced by recent 3D visualization techniques. In... more
In volume-rendering applications the input data is usually acquired by measuring some kind of phys-ical property. The accuracy of the measurement strongly influences the quality of images produced by recent 3D visualization techniques. In practice, however, a high ...
Systemic disease can produce changes in the nails. Perhaps the best known example of this is koilonychia as a sequale of iron deficiency anemia.... more
Systemic disease can produce changes in the nails. Perhaps the best known example of this is koilonychia as a sequale of iron deficiency anemia. "Half and half nail" is a type of pseudoleuconychia that can be caused by chronic renal disease, Kawasaki's disease, cirrhosis, and zinc deficiency. It has not been described in patients with Crohn's disease yet. Four male patients with Crohn's disease were observed. None of them had extraintestinal manifestations of Crohn's disease. The average duration of the disease was 5.25 (range, 1-10) years. The nail alterations were defined with a portion of the nail being as much as 15 to 40 percent of normal color distally, whereas the rest of the nail was white. The contrast between the two zones remains sharply demarcated even after constricting venous return. Histologic examination was not performed. Every patient had zinc deficiency but not hypalbuminaemia or sideropenia. After review of relevant literature (MEDLINE, PubMed, etc.), we found that half-and-half nail had not been described in Crohn's disease. This study was designed to highlight the fact that the half-and-half nail, which was thought to be a sign of chronic renal failure, also occurs in patients with Crohn's disease. The relationship of this symptom to clinical activity cannot yet be assessed and has only been observed in four cases.
Three-dimensional (3D) image rendering was performed using data from standard CT examinations of the head. In this new method for 3D imaging of the brain surface interactive image segmentation and integral rendering were combined.... more
Three-dimensional (3D) image rendering was performed using data from standard CT examinations of the head. In this new method for 3D imaging of the brain surface interactive image segmentation and integral rendering were combined. Interactive segmentation operations meant that 3D images could be obtained within a short period of time. When combined with integral rendering this permits good-quality 3D views,
