Antioxidant, anti-inflammatory and neuroprotective actions of resveratrol after experimental nervous system insults. Special focus on the molecular mechanisms involved.

After different types of acute central nervous system insults, including stroke, subarachnoid haemorrhage and traumatic brain and spinal cord injuries, secondary damage plays a central role in the induction of cell death, neurodegeneration and functional deficits. Interestingly, secondary cell death presents an attractive target for clinical intervention because the temporal lag between injury and cell loss provides a potential window for effective treatment. While primary injuries are the direct result of the precipitating insult, secondary damage involves the activation of pathological cascades through which endogenous factors can exacerbate initial tissue damage. Secondary processes, usually interactive and overlapping, include oxidative stress, neuroinflammation and dysregulation of autophagy, ultimately leading to cell death. Resveratrol, a natural stilbene present at relatively high concentrations in grape skin and red wine, exerts a wide range of beneficial health effects. Within the central nervous system, in addition to its inherent free radical scavenging role, resveratrol increases endogenous cellular antioxidant defences thus modulating multiple synergistic pathways responsible for its antioxidant, anti-inflammatory and anti-apoptotic properties. During the last years, a growing body of in vitro and in vivo evidence has been built, indicating that resveratrol can induce a neuroprotective state and attenuate functional deficits when administered acutely after an experimental injury to the central nervous system. In this review, we summarize the most recent findings on the molecular pathways involved in the neuroprotective effects of this multi target polyphenol, and discuss its neuroprotective potential after brain or spinal cord injuries.

Intrathecal Administration of an Anti-nociceptive Non-CpG Oligodeoxynucleotide Reduces Glial Activation and Central Sensitization.

Inflammatory pain associates with spinal glial activation and central sensitization. Systemic administration of IMT504, a non-CpG oligodeoxynucleotide originally designed as an immunomodulator, exerts remarkable anti-allodynic effects in rats with complete Freund´s adjuvant (CFA)-induced hindpaw inflammation. However, the anti-nociceptive mechanisms of IMT504 remain unknown. Here we evaluated whether IMT504 blocks inflammatory pain-like behavior by modulation of spinal glia and central sensitization. The study was performed in Sprague Dawley rats with intraplantar CFA, and a single lumbosacral intrathecal (i.t.) administration of IMT504 or vehicle was chosen to address if changes in glial activation and spinal sensitization relate to the pain-like behavior reducing effects of the ODN. Naïve rats were also included. Von Frey and Randall-Selitto tests, respectively, exposed significant reductions in allodynia and mechanical hypersensitivity, lasting at least 24 h after i.t. IMT504. Analysis of electromyographic responses to electrical stimulation of C fibers showed progressive reductions in wind-up responses. Accordingly, IMT504 significantly downregulated spinal glial activation, as shown by reductions in the protein expression of glial fibrillary acidic protein, CD11b/c, Toll-like receptor 4 (TLR4) and the phosphorylated p65 subunit of NFκB, evaluated by immunohistochemistry and western blot. In vitro experiments using early post-natal cortical glial cultures provided further support to in vivo data and demonstrated IMT504 internalization into microglia and astrocytes. Altogether, our study provides new evidence on the central mechanisms of anti-nociception by IMT504 upon intrathecal application, and further supports its value as a novel anti-inflammatory ODN with actions upon glial cells and the TLR4/NFκB pathway. Intrathecal administration of the non-CpG ODN IMT504 fully blocks CFA-induced mechanical allodynia and hypersensitivity, in association with reduced spinal sensitization. Administration of the ODN also results in downregulated gliosis and reduced TLR4-NF-κB pathway activation. IMT504 uptake into astrocytes and microglia support the concept of direct modulation of CFA-induced glial activation.

Resveratrol exerts anti-oxidant and anti-inflammatory actions and prevents oxaliplatin-induced mechanical and thermal allodynia.

Chemotherapy-induced peripheral neuropathic pain (CIPNP) is a frequent and devastating side effect of cancer therapy. No preventive strategies are currently available. We investigated the use of resveratrol (RESV) in the prevention of CIPNP and evaluated key components of the antioxidant defense system and neuroinflammatory factors as possible mediators contributing to RESV actions. Male rats were injected with oxaliplatin (OXA) and received daily oral RESV. Paw mechanical and thermal allodynia, oxidative stress, antioxidant, pro-inflammatory and neuronal injury/activation markers were evaluated in the sciatic nerve (SN), lumbar dorsal root ganglia (DRG) and spinal cord (SC). OXA-injected animals developed mechanical and thermal allodynia, while those receiving OXA + RESV showed patterns of response similar to control animals. Higher TBARS levels and lower GSH/GSSG ratios were observed in the SN of animals receiving OXA. The mRNA levels of the transcription factor NFκB and the pro-inflammatory cytokine TNFα were found to be upregulated both in lumbar DRG and SC. In addition, the antioxidant enzymes NQO-1 and HO-1 and the neuronal injury marker ATF3 showed increased levels of expression in lumbar DRG. In the dorsal SC the neuronal activation marker c-fos and the transcription factor Nrf2, main regulator of antioxidant defenses, were found to be upregulated. RESV early and sustained administration prevented NFκB, TNFα, ATF3 and c-fos upregulation, while increasing the expression of Nrf2, NQO-1, HO-1 and the redox-sensitive deacetylase SIRT1. RESV treatment was also able to restore TBARS levels and GSH/GSSG ratio. Thus, RESV administration resulted in the upregulation of antioxidant mediators, suppression of pro-inflammatory parameters and prevention of OXA-induced mechanical and thermal allodynia.

Small RNAs from a Big Genome: The piRNA Pathway and Transposable Elements in the Salamander Species Desmognathus fuscus.

Most of the largest vertebrate genomes are found in salamanders, a clade of amphibians that includes 686 species. Salamander genomes range in size from 14 to 120 Gb, reflecting the accumulation of large numbers of transposable element (TE) sequences from all three TE classes. Although DNA loss rates are slow in salamanders relative to other vertebrates, high levels of TE insertion are also likely required to explain such high TE loads. Across the Tree of Life, novel TE insertions are suppressed by several pathways involving small RNA molecules. In most known animals, TE activity in the germline is primarily regulated by the Piwi-interacting RNA (piRNA) pathway. In this study, we test the hypothesis that salamanders' unusually high TE loads reflect the loss of the ancestral piRNA-mediated TE-silencing machinery. We characterized the small RNA pool in the female and male adult gonads, testing for the presence of small RNA molecules that bear the characteristics of TE-targeting piRNAs. We also analyzed the amino acid sequences of piRNA pathway proteins from salamanders and other vertebrates, testing whether the overall patterns of sequence divergence are consistent with conserved pathway function across the vertebrate clade. Our results do not support the hypothesis of piRNA pathway loss; instead, they suggest that the piRNA pathway is expressed in salamanders. Given these results, we propose hypotheses to explain how the extraordinary TE loads in salamander genomes could have accumulated, despite the expression of TE-silencing machinery.

Bone marrow stromal cells attenuate injury-induced changes in galanin, NPY and NPY Y1-receptor expression after a sciatic nerve constriction.

Single ligature nerve constriction (SLNC) of the rat sciatic nerve triggers neuropathic pain-related behaviors and induces changes in neuropeptide expression in primary afferent neurons. Bone marrow stromal cells (MSCs) injected into the lumbar 4 (L4) dorsal root ganglia (DRGs) of animals subjected to a sciatic nerve SLNC selectively migrate to the other ipsilateral lumbar DRGs (L3, L5 and L6) and prevent mechanical and thermal allodynia. In this study, we have evaluated the effect of MSC administration on the expression of the neuropeptides galanin and NPY, as well as the NPY Y(1)-receptor (Y(1)R) in DRG neurons. Animals were subjected to a sciatic nerve SLNC either alone or followed by the administration of MSCs, phosphate-buffered saline (PBS) or bone marrow non-adherent mononuclear cells (BNMCs), directly into the ipsilateral L4 DRG. Seven days after injury, the ipsilateral and contralateral L4-5 DRGs were dissected out and processed for standard immunohistochemistry, using specific antibodies. As previously reported, SLNC induced an ipsilateral increase in the number of galanin and NPY immunoreactive neurons and a decrease in Y(1)R-positive DRG neurons. The intraganglionic injection of PBS or BNMCs did not modify this pattern of expression. In contrast, MSC administration partially prevented the injury-induced changes in galanin, NPY and Y(1)R expression. The large number of Y(1)R-immunoreactive neurons together with high levels of NPY expression in animals injected with MSCs could explain, at least in part, the analgesic effects exerted by these cells. Our results support MSC participation in the modulation of neuropathic pain and give insight into one of the possible mechanisms involved.

[The HOMA and QUICKI indexes, and insulin and C-peptide levels in healthy children. Cut off points to identify metabolic syndrome in healthy children]. / Indice HOMA y QUICKI, insulina y péptido C en niños sanos. Puntos de corte de riesgo cardiovascular.

OBJECTIVE: The aim of this study was to establish the reference values of the Homeostasis Model Assessment (HOMA) and Quantitative Insulin Sensitivity Check (QUICKI) indexes, as well as those of insulin and C-peptide levels in healthy children and adolescents with a view to determining reference percentiles to detect those at cardiovascular risk. MATERIAL AND METHODS: A total of 372 children boys and girls of different ages and at distinct pubertal stages with normal body mass index participated in the study. Fasting glucose, insulin and C-peptide values were measured by chemiluminescence and the HOMA and QUICKI indexes were calculated. RESULTS: Fasting glucose levels were normal in all children. The mean values obtained for each variable were (mean (SD)): fasting glucose 87(7.75) mg/dL, insulin 7.74 (5.35) microU/mL, C-peptide: 1.76 (0.79) ng/mL, HOMA index 1.72 (1.27) and QUICKI index 0.72 (0.29). All the variables progressively increased with age, with statistically significant differences between prepubertal and pubertal children. The QUICKI index showed an inverse relationship. In addition, significant differences were found between sexes. The 90th percentile for all the variables was as follows: insulin 15.05 microU/mL, C-peptide: 2.85 ng/mL, HOMA index 3.43 and QUICKI index 1.10. CONCLUSIONS: Values of fasting glucose, insulin, C-peptide and the HOMA index significantly increased with age and pubertal stage, while the QUICKI index decreased. We defined the 90th percentile for all the parameters studied as the cut-off point to identify children at cardiovascular risk in our population.

Presence of alpha-globin mRNA and migration of bone marrow cells after sciatic nerve injury suggests their participation in the degeneration/regeneration process.

We have previously reported that in the distal stump of ligated sciatic nerves, there is a change in the distribution of myelin basic protein (MBP) and P0 protein immunoreactivities. These results agreed with the studies of myelin isolated from the distal stump of animals submitted to ligation of the sciatic nerve, showing a gradual increase in a 14 kDa band with an electrophoretic mobility similar to that of an MBP isoform, among other changes. This band, which was resolved into two bands of 14 and 15 kDa using a 16% gel, was found to contain a mixture of MBP fragments and peptides with great homology with alpha- and beta-globins. In agreement with these results, we have demonstrated that the mRNA of alpha-globin is present in the proximal and distal stumps of the ligated nerve. It is also detected at very low levels in Schwann cells isolated from normal nerves. These results could be due to the presence of alpha- and/or beta-globin arising from immature cells of the erythroid series. Also, they could be present in macrophages, which spontaneously migrate to the injured nerve to promote the degradation of myelin proteins. Cells isolated from normal adult rat bone marrow which were injected intraortically were found to migrate to the injured area. These cells could contribute to the remyelination of the damaged area participating in the removal of myelin debris, through their transdifferentiation into Schwann cells or through their fusion with preexisting Schwann cells in the distal stump of the injured sciatic nerve.

The S-phase fraction of the aneuploid cell subpopulation is the biologically relevant one in aneuploid breast cancers.

BACKGROUND: In the case of DNA-aneuploid tumors there are no clear guidelines as to which S-phase fraction is the more relevant one: that corresponding to either the diploid or the aneuploid population, or rather an average of both. MATERIALS AND METHODS: We studied 280 breast cancer specimens from previously untreated patients. Histologically, 231 were ductal infiltrating carcinomas, 30 lobular infiltrating carcinomas and 19 corresponded to other, less frequent varieties. Postsurgically, 164 cases (58.6%) were classified as T1, 87 (31.1%) as T2 and 7 as T3. The remaining 22 cases were multifocal, diffuse tumors. Flow cytometry was performed on fresh tumor tissue, and immunohistochemistry for hormone receptors, Ki67, c-erb-B2 and p53 on paraffin-embedded material. RESULTS: In diploid tumors, a high S-phase (above the 75th percentile) correlated significantly with Ki67 expression > or =20% (p<0.0001). In aneuploid tumors, however, this was only the case for the aneuploid fraction of tumor cells (p< 0.0001). A high S-phase of diploid tumors correlated directly and significantly with a high histologic grade (p=0.04), a high nuclear grade (p=0.01), tumor size (p=0.0008), and inversely with estrogen (p<0.0001) and progesterone (p<0.0001) receptor expression. In aneuploid tumors, the aneuploid tumor fraction showed a direct and significant correlation with a high histologic grade (p=0.005), a high nuclear grade (p=0.001), mutant p53 expression (p=0.0009), and inversely with estrogen (p<0.0001) and progesterone (p=0.0001) receptor expression. A high S-phase of the diploid cell fraction of aneuploid tumors, on the other hand, just showed an inverse correlation with high nuclear grade of the tumors (p=0.02), and none whatsoever with all other tested parameters.

Effect of a graded single constriction of the rat sciatic nerve on pain behavior and expression of immunoreactive NPY and NPY Y1 receptor in DRG neurons and spinal cord.

In the present study, the rat sciatic nerve was constricted to varying degrees using only one ligature with a very thin polyethylene sheath placed between nerve and ligature thread. Complete nerve transection was studied for comparison. With a 40-80% constriction of the nerve we observed allodynia to a similar extent as in the so-called Bennett model based on four loose ligatures. We also monitored changes in the expression of neuropeptide Y (NPY) and the NPY Y1 receptor (Y1R) in the lumbar 4-5 dorsal root ganglia (DRG) and dorsal horn and found upregulation of NPY and downregulation of the Y1R in DRG neurons after injury. These results indicate that similar peptide and receptor changes occur in this model as after axotomy and in other nerve injury models, although the immunohistochemical and behavioral changes seem to be dependent on the degree of constriction of the nerve. Thus, it seems relevant to monitor the degree of constriction when evaluating pain and other post-injury events. The possibility that some of the changes in NPY-ergic neurotransmission are related to the generation of allodynia is discussed; as well as the possibility to use this mononeuropathic model based on a single ligature nerve constriction (SLNC) as a complementary approach to other widely used pain models.

The X-chromosome RBMX Gene is Expressed in Mammary Carcinoma.

BACKGROUND: A gene located on the q11.23 region of the male chromosome, RBMY, which plays a role in spermatogenesis, is down-regulated in testicular cancer. RBMY is a diverged X-Y shared gene. The corresponding X chromosome gene, RBMX, is located on Xq26. MATERIALS AND METHODS: We studied fresh tissues from 122 infiltrating breast cancers (99 ductal infiltrating, 19 lobular infiltrating and 4 tubular carcinomas) for the expression of RBMX by means of differential RT-PCR (reverse transcription-polymerase chain reaction), using beta-actin as an internal control and normalization standard. The obtained results were compared with all available clinical and molecular data of the studied tumors (estrogen and progesterone receptors (ER & PR), c-erb-B2, p53, Ki67, DNA-ploidy, Bcl-2, VEGF, CD105 (endoglin), histologic variety, histologic and nuclear grade and axillary node invasion). RESULTS: RBMX RT-PCR was successful in 120/122 instances. All 120 cases expressed RBMX. The only significant correlation found between RBMX expression and all the variables tested was an inverse one with CD105 (endoglin) mRNA-expression (r=-3063; p=0.0007). CONCLUSION: The X-chromosome RBMX gene is expressed in all breast cancers. The expression is inversely correlated with the expression of the angiogenesis-associated CD105 (endoglin) gene. The precise meaning of this association has still to be elucidated.

Elevated mammaglobin (h-MAM) expression in breast cancer is associated with clinical and biological features defining a less aggressive tumour phenotype.

BACKGROUND: Mammaglobin (h-MAM) is expressed mainly by breast epithelial cells, and this feature has been used to detect circulating breast cancer cells and occult metastases in sentinel axillary lymph nodes of breast cancer patients. However, the biological role of mammaglobin is completely unknown. METHODS: We studied 128 fresh-frozen breast cancer specimens by means of reverse transcriptase-polymerase chain reaction and quantified their h-MAM mRNA expression. This was then correlated with histological and nuclear grade, oestrogen and progesterone receptor expression, c-erb-B2 and mutant p53 expression, as well as with cellular proliferation measured by means of the Ki67 labelling index, DNA ploidy and S-phase, and finally with the presence or not of invaded axillary nodes in the mastectomy specimen. RESULTS: In the univariate analysis, high h-MAM expression (above the median for the whole group) correlated significantly (P < 0.05) with oestrogen and progesterone receptor expression, diploid DNA content, low Ki67 labelling index, low nuclear grade and almost significantly (P = 0.058) with the absence of axillary nodal invasion in the mastectomy specimen. In a final, multivariate model, only progesterone receptor expression, diploid DNA content and absence of nodal invasion were found to be independently associated with high h-MAM expression. CONCLUSION: All of the features associated with mammaglobin expression reflect, without exception, a less aggressive tumour phenotype. Further studies are needed to clarify whether this is attributable to h-MAM expression itself, or to another mechanism of which mammaglobin expression forms part.

Immunofluorometric study of Bcl-2 and Bax expression in clinical fresh tumor samples from breast cancer patients.

BACKGROUND: The balance between the expression of the antiapoptotic gene Bcl-2 and the proapoptotic gene Bax is considered a good indicator of the apoptotic activity of tumor cells. Bcl-2 and Bax expression seem also to individually play a prognostic role in breast cancer. Our aim was to study the expression of both genes in fresh breast cancer samples, and to correlate the obtained results with other available clinical and biological parameters of the tumors. MATERIALS AND METHODS: Fresh tumor specimens from 86 breast cancer patients were studied by means of immunofluorocytometry for the expression of the apoptosis-associated Bcl-2 and Bax genes. Additionally, DNA-ploidy was also measured. Paraffin blocks corresponding to the same tumors were used for immunohistochemistry, to study the expression of hormone receptors (ER and PR), p53, c-erb-B2 and the Ki67 labelling index. Fourteen patients had been treated with four cycles of induction chemotherapy (cyclo-phosphamide, adriamycin and 5-fluorouracil), and separate statistical analyses were carried out both for the whole group, and for the 62 patients not having received any treatment whatsoever, in order to exclude any potential influence of the chemotherapeutic treatment on the expression of the studied antigens. RESULTS: Bcl-2 expression correlated significantly with estrogen (p = 0.002) and progesterone (p = 0.012) receptor expression, as well as with c-erb-B2 (p = 0.045) expression in chemotherapy-naïve tumors, the correlation being completely lost if treated tumors were added to the study group. A high apoptotic index (Bcl2/Bax < 0.5) correlated significantly with progesterone receptor expression (p = 0.037) and c-erb-B2 expression (p = 0.018), and this correlation was maintained, whether previously treated tumors were included into the study or not (p = 0.038 and p = 0.027, respectively). Bax expression did not correlate with any other clinical or biological parameters of the tumors, including Bcl-2 expression. CONCLUSION: Bcl-2 and Bax-expression can be easily determined in clinical breast cancer specimens by means of immunofluorocytometry. Bcl-2-expression significantly correlates with hormone-receptor- and c-erb-B2-expression exclusively in previously untreated tumors. This, however, seems only to be the case when considering Bcl-2 expression in isolation, since a high apoptotic index, which considers the ratio of Bcl-2 versus Bax expression in the same tumor, seems not to be affected by the previous use of chemotherapy.

D4 dopamine and metabotropic glutamate receptors in cerebral cortex and striatum in rat brain.

The characterization of the functional interactions between the metabotropic glutamate receptors (mGluR) and the dopaminergic (DR) receptors in the corticostriatal projections may provide a possible interpretation of synaptic events in the basal ganglia. It has been suggested that presynaptic D2-type receptor located on glutamatergic corticostriatal neurons regulates the release of glutamate. In a first approach we have studied the cellular distribution of the D4R and the mGluRs in cerebral cortex and striatum employing immunocytochemistry. D4R positive neurons were particularly numerous in medial prefrontal cortex mainly occupying layers II and III. An even distribution was found on small round-shaped neurons in the striatum. Group I mGluR1alpha-like immunoreactivity (mGluR1alpha-LI) was found in medial and deep layers of the cerebral cortex while group III mGluR4a labeled more superficial layers; group II mGluR2/3 signal was intense on fine fibers with a punctate appearance. In the striatum, mGluR1alpha and mGluR2/3 stained mainly fibers while mGluR4a labeled round shaped cell bodies. After lateral ventricular injection of colchicine, an axonal transport and firing activity blocker, D4R labeling significantly increased in cerebral cortex and decreased in the striatum. mGluR1alpha and mGluR4a signal decreased in cerebral cortex and only mGluR4a signal decreased in the striatum. These results support previous reports indicating a presynaptic localization of D4R in the striatum. In contrast, striatal mGluR1alpha appears to be a postsynaptic receptor probably synthesized in situ. Our results do not support the hypothesis of a colocalization of D4 receptor and one or more of the metabotropic glutamatergic receptors studied here.

Coexistence of neuropeptides and their possible relation to neuritic regeneration in primary cultures of magnocellular neurons isolated from adult rat supraoptic nuclei.

The coexistence of vasopressin (VP), oxytocin (OXY), galanin (GAL) and cholecystokinin (CCK) and the synthesis of GAL and CCK during neuritic regeneration was investigated in cultured magnocellular neurons, isolated from adult rat supraoptic nuclei. Double-labelling immunofluorescence was performed after 7 days of culture using primary antibodies for VP, OXY, GAL and CCK (paired in all possible combinations) and secondary antibodies labelled with either fluorescein or rhodamine. Confocal laser scanning microscopy revealed the coexistence of the mentioned peptides in all possible combinations, an unexpected result considering that the only combinations observed in tissue sections are VP-GAL and OXY-CCK. Freshly dispersed cells were devoid of any neuritic processes and showed a very poor immunocytochemical staining reaction for GAL and CCK. In contrast, neurons cultured for 7, 12 and 21 days showed many neurites and a strong immunoreactivity for GAL and CCK indicative of an increased synthesis of both peptides in the regenerating neurons. This increased synthetic activity is consistent with transient upregulation of these peptides observed in situ after hypophysectomy by other authors. The results suggest that the upregulation of GAL and CCK is functionally related to the neuronal regeneration processes observed during culture and that the 'uncommon' coexistences as well as the prolonged sythesis of GAL and CCK may be due to the lack of environmental inputs, which normally regulate the expression and up- and downregulation of these peptides in vivo.

Oligodendroglial cell differentiation in rat brain is accelerated by the intracranial injection of apotransferrin.

In the present paper we first studied the brain distribution and the time and dose dependent effects of apotransferrin, after its intracranial injection into young rats and at different post-natal ages. Its action upon the transferrin receptor (TfR) and upon the expression of brain transferrin, as well as its effect on the proliferation and differentiation of oligodendroglial cells (OLGc) was one of the main objectives of our investigation. Total DNA and BrdU labeling, as an index of cellularity and proliferation, respectively, were the same in the control and experimental groups of rats. A significant increase in the MBP+ and CA II+ OLGc, and a decrease in the more immature (A2B5+) OLGc were found in the aTf injected rats. At 10 and 17 days of age, Tf-mRNA decreased to around 20% of the amount present in control animals. The TfR-mRNA in the animals receiving a single dose of aTf at 3 days of age showed an increase in its expression at 10 and 17 days of age, coincident with a higher immunoreactivity of the TfR itself of neurons, choroid plexus and brain capillaries in different brain areas. Although TfR+ OLGc were present up to 7 days of age in controls and in the Tf injected rats, no positive cells were observed at 17 days of age, even in the aTf injected rats. Our results give support to the hypothesis that aTf is an important factor necessary for the maturation of the OLGc, and that the effects that it produces in the OLGc-myelin unit after its intracranial injection in young rats are not due to an increase in proliferation, but to an accelerated differentiation of Tf-sensitive OLGc.

[Suprarenal myelolipoma: an "incidental" disease]. / Mielolipoma suprarrenal: una patología "incidental".

With the development and improvement of imaging techniques, we are witnessing a greater number of disease diagnoses considered uncommon only a few years ago. When the diagnosis of a tumoral disease occurs "incidentally" while performing an imaging examination for other reasons, we name the condition "INCIDENTALOMA". A clear example of these in suprarenal conditions is the myelolipoma. Myelolipoma is a benign and non-functioning tumour originating in the suprarenal cortex and histologically consisting of mature fat and haemopoietic tissue. Given its benign and usually inactive nature, the current approach is a conservative attitude. Surgical exeresis is only accepted when large tumoral masses are present or in complicated cases. This paper presents a new case of a 10 cm suprarenal myelolipoma incidentally diagnosed during routine ultrasound examination in a 47-year old male patient. Subsequent exeresis of the suprarenal mass and pathohistological study confirmed the diagnosis.

Interaction of skeletal muscle cells with collagen type IV is mediated by perlecan associated with the cell surface.

We have previously shown that the expression of perlecan, a heparan sulfate proteoglycan localized on the myoblast surface, is down-regulated during terminal differentiation of skeletal muscle myoblasts (Larraín et al. [1997] Exp. Cell Res. 234:405-412). In this study, we have evaluated the biochemical characteristics of perlecan, its association with the myoblast surface, and its involvement in C(2)C(12) myoblast adhesion to different substrates. Perlecan associated with myoblasts was solubilized by Triton X-100, whereas heparin, high salt, and RGD peptides were unable to solubilize perlecan. Pre-incubation of myoblasts with [(35)S]-Na(2)SO(4), followed by solubilization with Triton X-100 and immunoprecipitation with antibodies against murine perlecan, demonstrated that this proteoglycan present on the cell surface has a heterogeneous size profile with a K(av) value of 0.45, determined by Sepharose CL-4B chromatography. Myoblasts were found to adhere with decreasing affinities to collagen type IV, type I, laminin, fibronectin, perlecan, and matrigel. We found that cell adhesion to collagen type IV was inhibited by blocking this substrate with exogenous perlecan prior to cell plating, whereas no effect was observed for laminin. Furthermore, adhesion of myoblasts to collagen type IV was inhibited by the perlecan core protein obtained by treatment of perlecan with heparitinase, as well as by pre-incubation of the cells with antibodies against murine perlecan. These data support the idea that skeletal muscle cells interact with collagen type IV through the perlecan core protein present on the surface of undifferentiated myoblasts.