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At least 739 records · Page 41Linked to original sources
PubMed2005

Regional difference in corticotropin-releasing factor immunoreactivity in mossy fiber terminals innervating calretinin-immunoreactive unipolar brush cells in vestibulocerebellum of rolling mouse Nagoya.

Unipolar brush cells (UBCs), a class of interneurons in the vestibulocerebellum, play roles in amplifying excitatory inputs from vestibulocerebellar mossy fibers. This study aimed to clarify whether corticotropin-releasing factor (CRF)-positive mossy fiber innervation of calretinin (CR)-positive UBCs was altered in rolling mouse Nagoya (RMN). The distribution and the number of CR-positive UBCs in the vestibulocerebellum were not different between RMN and control mice. Double immunofluorescence revealed that some CRF-positive mossy fiber terminals were in close apposition to CR-positive UBCs. In the lobule X of vermis, such mossy fiber terminals were about 5-fold greater in number in RMN than in controls. In contrast, the number of CRF-positive mossy fiber terminals adjoining CR-positive UBCs in the flocculus was not significantly different between RMN and controls. The results suggest increased number of CRF-positive mossy fiber terminals innervating CR-positive UBCs in the lobule X but not in the flocculus of RMN. CRF may alter CR-positive UBC-mediated excitatory pathways in the lobule X of RMN and may disturb functions of the lobule X such as cerebellar adaptation for linear motion of the head.

Animals↗
PubMed2005

Immunodetection of heparin-binding growth associated molecule (pleiotrophin) in striatal interneurons.

Pleiotrophin (PTN), a developmentally-regulated trophic factor, is over-expressed in the striatum of parkinsonian rats. Because striatal PTN can provide trophic support to dopamine neurons, we identified the cellular types containing PTN in the striatum of adult rats. By means of fluorescent double-immunolabeling, we found PTN to co-localize with a neuronal nuclei marker but not with glial fibrillary acidic protein. The number, distribution, and morphology of the PTN-immunolabeled cells suggested that they were interneurons. Further double-immunolabeling studies ruled out PTN localization to calretinin- and parvalbumin-containing interneurons. Instead, approximately 40% of the PTN-immunolabeled neurons contained nitric oxide synthase or somatostatin and approximately 60% expressed the vesicular acetylcholine transporter, supporting that they were GABAergic nitric oxide synthase/somatostatin-containing and cholinergic interneurons. Further work is necessary to determine if PTN from striatal interneurons can provide trophic support to dopamine neurons.

Animals↗
PubMed2006

Neuronal apoptosis and gray matter heterotopia in microcephaly produced by cytosine arabinoside in mice.

Primary microcephaly can be accompanied by numerous migration anomalies. This experiment was undertaken to examine the pathogenesis of gray matter heterotopia and microcephaly that is produced after administering cytosine arabinoside (Ara-C) to mice. Pregnant mice were intraperitoneally injected with Ara-C at 30 mg/kg body weight on days 13.5 and 14.5 of gestation, and then their offspring were examined. On embryonic day 15.5, in the ventricular zone of the cingulate cortex, the neuroepithelial cells lacked BrdU immunoreactivity. Nestin-immunoreactive radial glial fibers and calretinin-positive subplate fibers were disrupted. TUNEL reaction was remarkable throughout the cerebral hemisphere. Subcortical heterotopia in the cingulate cortex and subependymal nodular heterotopia in the dorsolateral part of the lateral ventricles became detectable by the first day after birth. Thirty-two days after birth, microcephaly was apparent; subcortical heterotopia was observed to have increased in size while it was still located in the frontal and cingulate cortices. This experiment demonstrated that Ara-C induces neuronal apoptosis throughout the cerebral hemisphere. The immunohistochemical characteristics in the gray matter heterotopia suggest that both the subcortical and the subependymal heterotopias were formed by neurons originally committed to the neocortex. We conclude that the gray matter heterotopia that accompanies the microcephaly was produced by a disturbance of radial, tangential, and interkinetic neuronal migrations due to the toxicity of Ara-C in the immature developing brain.

Animals↗
PubMed2006

Calretinin distribution in the octopus brain: an immunohistochemical and in situ hybridization histochemical analysis.

The distribution of calretinin containing neurons examined by in situ hybridization mapping was compared with that obtained by immunocytochemistry in the brain of octopus. Results revealed a close correspondence between the two types of investigations. Western blot analysis disclosed a 29 kDa protein immunostained with anti-calretinin antibody. Calretinin containing neurons were localized mainly in the cortex of octopus lobes, including the vertical, frontal, basal, buccal, palliovisceral, pedal and branchial, with variations of staining intensity and density of immunoreactive cells. The amacrine cells surrounding calretinin containing neuronal bodies of the cortex were also labeled unlike the glial cells. The close correspondence of blotting analysis, immunocytochemistry and in situ hybridization indicates with no doubt that calretinin, like other calcium-binding proteins previously studied, is also present in the nervous system of cephalopods. Furthermore, although recent findings localize calretinin also in endocrine glands, the presence of this calcium-binding protein in the brain of octopus indicates that calretinin appeared early in the phylogeny as a neuronal protein already in invertebrates.

Amacrine Cells↗
PubMed2005

Chemoarchitecture of the dorsal column nucleus of the larval sea lamprey.

We studied the organization of the dorsal column nucleus (DCN) of larval sea lamprey with immunohistochemical and tract-tracing techniques. Texas red-coupled dextran amine was injected into the spinal cord, which allowed tracing the dorsal column fibers and characterizing the DCN. The dorsal column fibers formed a dense tract coursing adjacent to the dorsal midline of the spinal cord to the caudal rhombencephalon alar plate. In larvae, most spinal cord dorsal cells and spinal ganglion perikarya, and many dorsal column fibers, were calretinin-immunoreactive. We delineated the DCN in the dorsomedial portion of the obex and preobecular alar plate. It consists of a periventricular neuronal cell layer and neurons scattered in the lateral neuropil and receives dorsal column fibers. After immunohistochemistry with antibodies against glutamate, glycine, and GABA numerous immunoreactive perikarya were observed in the DCN. In addition to glutamate-, glycine-, and GABA-immunoreactive processes, serotonin- and dopamine-immunoreactive fibers coursed in the neuropil of this nucleus. A few small calretinin-immunoreactive perikarya were also observed in the DCN. Our results reveal the presence of inhibitory and excitatory transmitters in neurons of the DCN, and suggest that dopamine and serotonin modulate the activity of this nucleus.

Animals↗
PubMed2006

Detection of hypoxia-related proteins in medaka (Oryzias latipes) brain tissue by difference gel electrophoresis and de novo sequencing of 4-sulfophenyl isothiocyanate-derivatized peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Two-dimensional fluorescence-based difference gel electrophoresis (DIGE) was used in combination with matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) to identify a set of hypoxia-related biomarker proteins in medaka (Oryzias latipes) brain tissue. Each of the proteins were identified via de novo sequencing of tryptic peptides derivatized with 4-sulfophenyl isothiocyanate (SPITC), which N-terminally sulfonates peptides and promotes facile post-source decay peptide fragmentation, resulting in greatly simplified spectra consisting mainly of y-series fragment ions. We also report that addition of the non-ionic surfactant n-octyl-beta-d-glucopyranoside significantly improves SPITC-derivatized peptide recoveries. In addition, we found that a MALDI matrix consisting of the sodium-tolerant matrix 2,4,6-trihydroxyacetophenone, diammonium citrate, and alpha-cyano-4-hydroxycinnamic acid also improves ionization of SPITC-peptides, presumably by reducing ionization suppression effects from matrix contaminants, especially sodium cations. The DIGE experiments and analyses resulted in detection of six abundant proteins and related isozymes up-regulated (>1.49, p<0.005) in hypoxic medaka brain tissues, including two hemoglobin beta subunit forms, four carbonic anhydrase 2 forms, calbindin, aldolase, succinate dehydrogenase, and glutathione-S-transferase.

Animals↗
PubMed2004

Postnatal development of the alpha1 containing GABAA receptor subunit in rat hippocampus.

Here we have studied the developmental expression of alpha1 subunit of the GABAA receptor in comparison with the expression of alpha2 subunit and several GABAergic markers (parvalbumin (PV), calretinin (CR), somatostatin (SOM), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP)). The alpha1 expression (mRNA and protein) was low at birth and increased progressively until the adulthood. This expression pattern was similar to that observed for PV, opposite to that of CR (high at birth and decreased continuously until the adulthood) and differed from that observed for the alpha2 and neuropeptides (SOM, NPY and VIP) (in all cases, a clear peak in expression was observed at P10). We further investigated the expression of alpha1, PV and CR by immunohistochemistry. As expected, the alpha1 and the PV expression were low at birth and increased progressively until the adulthood. Both alpha1 and PV were co-expressed by the same interneuronal population, however, the maturation of the alpha1 subunit preceded to that of PV. Finally, we observed a gradient of maturation between the different fields of the hippocampus proper (CA2-3 preceded to CA1 and DG). This gradient could be related to the high expression of CR positive cells and fibers during the first 10 postnatal days, located principally in the stratum lacunosum moleculare of the CA2-3 layers.

Aging↗
PubMed2004

Deletion of the Pemt gene increases progenitor cell mitosis, DNA and protein methylation and decreases calretinin expression in embryonic day 17 mouse hippocampus.

Choline is a required nutrient and is derived from the diet as well as from de novo synthesis catalyzed by phosphatidylethanolamine N-methyltransferase (PEMT). We previously reported that choline availability during pregnancy alters mitosis and neuronal protein expression during fetal brain development in wild-type mice and rats, and that Pemt-/- mice become choline deficient. In this study, we examined brain development in these knockout mice. Pregnant Pemt-/- and wild-type mice were fed AIN-76A diet until gestation day 17 (E17) when the fetal brains were harvested. Phosphorylation of histone H3 (a measure of mitosis) and calretinin (a GABAergic neuronal marker) were assessed in hippocampal regions. We observed increased numbers of phosphorylated histone H3 positive cells in the Pemt-/- mice (up 54% compared to wild-type mice; p<0.01). We also found decreased calretinin labeling in Pemt-/- (down to 43% compared to wild-type mice; p<0.01). Thus, there was increased stem cell proliferation in the neuroepithelium and decreased GABAergic neuronal differentiation of these animals on E17. These results are opposite to what would have been expected in choline-deficient mice. The concentrations of S-adenosylmethionine (up 21%; p<0.05) and methylation of DNA (up 46%) and proteins (up 12%; p<0.01) in hippocampus were significantly increased in Pemt-/- mice, suggesting that increased S-adenosylmethionine availability may mediate the observed developmental changes. This is the first report of altered brain development in Pemt-/- mice.

Acyltransferases↗
PubMed2004

Evidence of newly generated neurons in the human olfactory bulb.

The subventricular zone (SVZ) is known to be the major source of neural stem cells in the adult brain. In rodents and nonhuman primates, many neuroblasts generated in the SVZ migrate in chains along the rostral migratory stream (RMS) to populate the olfactory bulb (OB) with new granular and periglomerular interneurons. In order to know if such a phenomenon exists in the adult human brain, we applied single and double immunostaining procedures to olfactory bulbs obtained following brain necropsy in normal adult human subjects. Double immunofluorescence labelling with a confocal microscope served to visualize cells that express markers of proliferation and immature neuronal state as well as markers that are specific to olfactory interneurons. Newborn cells that express cell cycle proteins [Ki-67, proliferating cell nuclear antigen (PCNA)] were detected in the granular and glomerular layers (GLs) of the human olfactory bulb; these cells coexpressed markers of immature neuronal state, such as Doublecortin (DCX), NeuroD and Nestin. Numerous differentiating cells expressed molecular markers of early committed neurons [beta-tubulin class III (TuJ1)] and were also immunoreactive for glutamic acid decarboxylase (GAD), a marker of GABAergic neurons, or tyrosine hydroxylase (TH), a marker of dopaminergic neurons. Other early committed neurons expressed the calcium-binding proteins calretinin (CR) or parvalbumin (PV). These results provide strong evidence for the existence of adult neurogenesis in the human olfactory system. Despite its relatively small size compared to that in rodents and nonhuman primates, the olfactory bulb in humans appears to be populated, throughout life, by new granular and periglomerular neurons that express a wide variety of chemical phenotypes.

Adult↗
PubMed2005

Area-specific effects of brain-derived neurotrophic factor (BDNF) genetic ablation on various neuronal subtypes of the mouse brain.

The effects of brain-derived neurotrophic factor (BDNF) on the development of presynaptic terminals and of neuronal subtypes in various brain areas were studied in BDNF-knockout (BDNF-/-) mice at postnatal days 15-17. Western analysis revealed no changes in the overall amount of a variety of synaptic proteins in BDNF-/- mice as compared to wild type mice. In addition, the complex between the vesicular proteins, synaptophysin and synaptobrevin, as well as their respective homodimers were unaltered. Moreover, no changes in the density of neurons were found in, e.g., the CA3 region of the hippocampus and the nucleus nervi facialis of BDNF-/- mice. However, cholinergic cells were reduced by 20% in the medial septum of BDNF-/- mice associated with a decrease in the activity of choline acetyltransferase and protein levels of nerve growth factor in the hippocampus by 16% and 44%, respectively. In the striatum, however, the total number of cholinergic cells were comparable in both groups, although the activity of choline acetyltransferase was decreased by 46%. In GABAergic interneurons, the expression of neuropeptides in various brain areas was differentially affected by BDNF deletion as revealed by immunohistochemistry. In the hippocampus and cortex of BDNF-/- mice, the density of neuropeptide Y-, somatostatin-, and parvalbumin-immunoreactive cells was drastically reduced, whereas the density of calretinin-positive cells was increased. The extent of these changes in neuropeptide-containing cells varied among hippocampal subregions. In the striatum, only the density of parvalbumin-immunoreactive cells was decreased by approximately 45%. In conclusion, BDNF deficiency is accompanied by a differential dysregulation in the expression of neuropeptides and calcium-binding proteins in otherwise intact GABAergic and glutamatergic neurons in a region-specific manner.

Age Factors↗
PubMed2005

Development of the human superior colliculus and the retinocollicular projection.

We have used carbocyanine dye tracing from the brachium of the superior colliculus in conjunction with Nissl staining and immunohistochemistry to GAP-43 and calretinin to study the development of retinal projections to the superior colliculus in 17 human embryos and fetuses aged from 8 to 28 weeks. Lamination of the superior colliculus begins to emerge by 11 weeks, and by 16 weeks all seven layers of the mature superior colliculus are visible. Fibres immunoreactive to GAP-43 were seen at 13 weeks in the most superficial layers. By 19 weeks, GAP-43 immunoreactivity was present in the stratum opticum as well as the deeper fibres layers, indicating the development of fibre pathways following those laminae. Carbocyanine dye tracing of retinocollicular projections showed extensive rostrocaudally running unbranched fibres in the superficial superior colliculus at 12 weeks. Shortly after this (13 weeks), retinocollicular fibres penetrate the deeper collicular layers and branching becomes apparent. We also saw occasional retrogradely labelled somata following DiI insertion into the superior brachium. Our findings indicate that development of the human superior colliculus and its connections is largely complete by 20 weeks. This would suggest that functional capacity of the human superior colliculus should also be mature by the middle of gestation.

Calbindin 2↗
PubMed2004

Progression of temporal lobe epilepsy in the rat is associated with immunocytochemical changes in inhibitory interneurons in specific regions of the hippocampal formation.

Immunocytochemical markers of specific rat hippocampal interneuron subpopulations, including the calcium binding proteins parvalbumin (PV), and calretinin (CR) were examined in relation to the evolution of spontaneous seizures after electrically induced status epilepticus (SE). PV/CR/NeuN immunoreactive neurons were counted in the hippocampal formation at different time intervals after SE and related to spontaneous hippocampal discharge activity. Decreased PV immunoreactivity was observed within 1 day after SE in the hilus, pre- and parasubiculum, and in the entorhinal cortex layers II and V/VI. In layer III, the density of detectable PV immunoreactive neurons did not decrease significantly, whereas the number of surrounding principal neurons was extensively decreased within a week in most post-SE rats, and after 3-4.5 months in all rats that had developed a progressive evolution of seizures. CR immunoreactive neuron number decreased in all hippocampal subregions except for the stratum lacunosum-moleculare and the EC layer II, in which the density did not decrease significantly. The apparent decrease in the number of PV and CR immunoreactive hilar neurons was correlated with the duration of the SE and was most extensive in rats with a progressive form of epilepsy. The loss of CR and PV expression or the loss of CR- and PV-containing neurons in specific regions of the hippocampal formation may play a role in the progressive nature of epilepsy possibly via increasing the entorhinal-hippocampal activity.

Animals↗
PubMed2005

Seizures induce proliferation and dispersion of doublecortin-positive hippocampal progenitor cells.

One neuropathological hallmark of temporal lobe epilepsy is granule cell dispersion, a widening of the hippocampal granule cell layer (GCL) with abnormally positioned excitatory neurons. The finding that seizure activity also induces adult hippocampal neurogenesis was taken largely as indicative of a regenerative attempt, not as part of the pathology. The aim of our study was to characterize a potential relationship between granule cell dispersion and seizure-induced neurogenesis. Kainic acid (KA)-induced seizures in mice led to increased cell proliferation and new neurons persisted for months after the seizures. We show that the proliferative stimulus did not affect nestin-expressing early precursor cells that primarily respond to physiologic mitogenic stimuli, but stimulated the division of late type-3 progenitor cells, which express doublecortin (DCX), a protein associated with cell migration. This delayed proliferation presumably interfered with migration, leading to a significant dispersion of DCX-positive progenitors and early postmitotic neurons within the dentate gyrus granule cell layer. We propose that initial seizures induce ectopic precursor cell proliferation resulting in the dispersion of immature neurons within the adult granule cell layer. Thus, seizure-generated neurons might contribute to the disease process of epilepsy.

Analysis of Variance↗
PubMed2005

Ectopic mesothelial cell proliferation in cervical lymph nodes after severe ovarian hyperstimulation syndrome.

OBJECTIVE: To report a case of ectopic mesothelial proliferation in cervical lymph nodes after severe ovarian hyperstimulation syndrome. DESIGN: Case report. SETTING: University-affiliated teaching hospital. PATIENT(S): A 42-year-old woman underwent a successful IVF attempt and developed severe ovarian hyperstimulation syndrome and pathologically enlarged cervical lymph nodes. INTERVENTION(S): Paracentesis, cervical lymph node biopsy followed by cytology, histology, and immunohistochemistry. MAIN OUTCOME MEASURE(S): Resolution of symptoms, pregnancy outcome, correct pathological diagnosis. RESULT(S): Paracentesis resulted in resolution of symptoms of ovarian hyperstimulation. The diagnosis of ectopic mesothelial proliferation in cervical lymph nodes was made after immunohistochemical examination of cervical lymph nodes. The pregnancy progressed normally, and at 40 weeks the patient spontaneously delivered a healthy son weighing 3,060 g. CONCLUSION(S): This case describes ectopic mesothelial cell proliferation localized in and around cervical lymph nodes occurring at 9 weeks' gestation in a patient who earlier developed severe ovarian hyperstimulation syndrome 10 days after ET. Ectopic mesothelial cell proliferation in lymph nodes is an extremely rare event, and this is the first case described after ovarian hyperstimulation. Familiarity with this event is important for the clinician as well as for the pathologist in preventing the misdiagnosis of malignancy.

Adult↗
PubMed2005

Disruption and restoration of cell-cell junctions in mouse vestibular epithelia following aminoglycoside treatment.

The intracellular junction complexes, which consist of tight junctions (TJ), adherens junctions (AJ), and desmosomes, mediate cell-cell adhesion in epithelial cells. E-cadherin, which is a major component of AJ, plays a role not only in the maintenance of cell-cell junctions, but also in repressing cell proliferation. In this study, we examined changes of E-cadherin expression in mouse vestibular epithelia following local application of neomycin using immunohistochemistry and western blotting, and morphology of cell-cell junctions by transmission electron microscopy (TEM). Immunohistochemistry and western blotting revealed down-expression of E-cadherin and its consecutive recovery. TEM demonstrated temporal disruption of cell-cell junctions. Morphology of cell-cell junctions was more rapidly restored than recovery of E-cadherin expression. Transient disruption of cell-cell junctions and down-expression of E-cadherin is a rational response for the deletion of dying hair cells, and may be associated with a limited capacity for cell proliferations in mammalian vestibular epithelia following their rapid restoration.

Adherens Junctions↗
PubMed2004

Expression of candidate tumor markers in ovarian carcinoma and benign ovary: evidence for a link between epithelial phenotype and neoplasia.

EpCAM, epithelial membrane antigen (EMA)-mucin 1 (MUC1), mesothelin, and CD9 have been reported to be overexpressed at the RNA level in ovarian carcinomas. By using immunohistochemistry, we profiled the protein expression of these gene products in ovarian carcinoma tissues and compared them with benign ovarian surface epithelium (OSE) and cortical inclusion cysts (CICs). Immunoreactivity for EMA and calretinin were used to define epithelial and mesothelial differentiation in nontumor tissues, respectively. Papillary serous (n = 16) and endometrioid (n = 10) tumors were immunopositive for EMA/MUC1 (100%), mesothelin (75% and 30%, respectively), CD9 (88% and 90%, respectively), and EpCAM (100%). All ovarian carcinomas and carcinoma cell lines tested were negative for calretinin. In nonneoplastic ovary, both OSE and CICs ranged from flat-to-cuboidal to stratified and ciliated in appearance. OSE with a cuboidal morphology had a similar immunoreactivity as omental peritoneum, expressing calretinin, mesothelin, and CD9. In contrast, CICs with stratified and ciliated epithelium show expression patterns similar to those in fallopian tubes. They frequently expressed EMA, EpCAM, mesothelin, and CD9. This immunophenotype is preserved in ovarian carcinomas, suggesting that Müllerian metaplasia signals the acquisition of these markers and that their expression is maintained in ovarian carcinomas that originate from this epithelium.

Antigens, CD↗
PubMed2005

The utility of calretinin, inhibin, and WT1 immunohistochemical staining in the differential diagnosis of ovarian tumors.

Calretinin has been proposed as a novel marker of ovarian sex cord-stromal tumors (SCST); this study aims to determine whether calretinin can complement or supplant the established utility of inhibin in the differential diagnosis of SCST. WT1 has been shown to be expressed in ovarian serous, but not mucinous neoplasms; its expression in a variety of ovarian tumors is also examined. Formalin-fixed, paraffin-embedded archival tissues from 111 primary ovarian tumors were analyzed with commercially available antibodies using semi-automated immunohistochemistry. Results were graded on a 4-tiered scale with staining of more than 0 but less than 5% of cells considered focal. Of 27 SCST, 56% were calretinin and 56% inhibin positive overall; 90% of granulosa cell tumors, 57% of Sertoli-Leydig cell tumors, 33% of thecomas, and 14% of fibromas were calretinin positive. Inhibin was expressed in 60% of granulosa cell tumors, 71% of Sertoli-Leydig cell tumors, 43% of fibromas, and 33% of thecomas. Of 35 surface epithelial tumors (SET), 8% of serous papillary tumors were calretinin positive, whereas 8% of serous papillary tumors and 13% of poorly differentiated carcinomas expressed inhibin. WT1 was expressed in 29% of all endometrioid carcinomas, 10% of borderline mucinous tumors, and no mucinous carcinomas; however, most of the other SETs were positive (77% serous papillary and 88% poorly differentiated carcinomas). Among the SCST, WT1 stained only granulosa cell tumors (75%), though often weakly or variably. Calretinin has only slightly greater sensitivity (76% versus 65%) and equal specificity to inhibin (92%) in the differential staining of granulosa or Sertoli-Leydig cell tumors, that is, nonstromal SCST. Hence, calretinin cannot replace but could complement inhibin as part of an immunohistochemical panel used for diagnostically challenging SCST. Although WT1 should be reliably positive in non-mucinous SET, staining of granulosa cell tumors and lack of expression in a sizable subset of endometrioid carcinomas may confound interpretation.

Adenocarcinoma↗
PubMed2006

Calretinin expression in tumors of adipose tissue.

Although well established as a marker of mesothelial cells, calretinin is also expressed in several other tissue types, including adipose tissue. Accordingly, immunohistochemical staining for calretinin has been described in an increasing number of neoplasms other than mesothelioma. A detailed analysis of calretinin expression in lipogenic tumors has not yet been reported, however. Given the known expression patterns of calretinin in normal tissues, we predicted that calretinin immunoreactivity would be detected in lipoma and the various histologic subtypes of liposarcoma, and that this marker might be of use in the differential diagnosis of selected fatty tumors. A variety of pleomorphic and small round cell sarcomas were studied for comparison. Calretinin immunoreactivity was detected, at least focally, in all 10 samples of normal adipose tissue and in 22 of 23 lipomas or lipoma variants. Staining for calretinin was also positive within the lipogenic component of 28 of 29 liposarcoma variants. Of the 7 dedifferentiated liposarcomas, 3 were focally positive for calretinin. Pleomorphic variants of other sarcomas, including undifferentiated high-grade pleomorphic sarcoma, rhabdomyosarcoma, leiomyosarcoma, and malignant peripheral nerve sheath tumor also exhibited focal calretinin immunoreactivity in a minority of cases, as did some small round cell sarcomas. These results suggest that calretinin immunoreactivity in normal and neoplastic adipose tissue is more ubiquitous than previously reported and may be a useful, albeit nonspecific marker of lipogenic differentiation. However, its utility in the differential diagnosis of fatty tumors appears limited.

Adipose Tissue↗