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Biomedical subjects

A Buonanno

Publications and source records attributed to A Buonanno.

At least 19 recordsLinked to original sources
PubMed2003

[PHS Repair in femoral hernia surgery].

BACKGROUND: Since December 2000 we began to treat femoral hernias, for the first time in emergency, placing the underlay mesh of a PHS 168; device in the properitoneal space using the same anterior way well known in plug technique repair. The technical description and short term effectiveness, safeness and comfort of our new femoral prosthetic repair are reported. METHODS: Prospective analysis of 12 unselected consecutive female patients who underwent 12 PHS device femoral hernia repairs (6 in emergency with 2 intestinal resections and 6 in elective settings), performed from December 2000 to December 2001 at the Institute of General Surgery, University of Ferrara. Mean age was 61,7 (range 25-94) and mean follow-up was 6 months (from 1 to 11). RESULTS: Mean hospital stay was 2.1 days (from 1 to 5). No recurrences or complications occurred. We report one (8.3%) 25 year old woman with moderate cruralgia which required analgesics assumption form more then 24 hours. CONCLUSIONS: Although our report is not statistical significant (recent introduction of this new technique for a low incidence rate pathology) actually we perform PHS device femoral hernia repair systematically, both in elective and emergency surgery. This new procedure appears as a simple, safe, effectiveness and comfortable, anterior properitoneal "tension-free" repair of the myopectineal region (direct inguinal hernias prophylaxis).

Adult↗
PubMed2001

ErbB transmembrane tyrosine kinase receptors are differentially expressed throughout the adult rat central nervous system.

The neuregulin (NRG) family of growth and differentiation factors and their erbB receptors contribute importantly to the development of the nervous system, but their distribution and function in the adult brain are poorly understood. The present study showed that erbB2, erbB3, and erbB4 transcripts and protein are distributed throughout all areas of adult rat brain. These three receptors were differentially expressed in neurons and glia. Some neurons expressed only a subset of erbB kinases, whereas other neurons expressed all three erbB receptors but sequestered each of these polypeptides into distinct cellular compartments. In synapse-rich regions, erbB immunoreactivity appeared as punctate-, axon-, and/or dendrite-associated staining, suggesting that NRGs are involved in the formation and maintenance of synapses in adult brain. ErbB labeling also was present in neuronal soma, indicating that NRGs act at sites in addition to the synapse. Glia in adult brain also differentially expressed erbB3 and erbB4. Approximately half of the erbB3 labeling in white matter was associated with S100beta+/glial fibrillary acidic protein negative macroglia (i.e., oligodendrocytes or glial fibrillary acidic protein negative astrocytes). In contrast, macroglia in gray matter did not express erbB3. The remaining erbB3 immunoreactivity in white matter and erbB4 glial staining seemed to be associated with microglia. These results showed that erbB receptors are expressed widely in adult rat brain and that each erbB receptor subtype has a distinct distribution. The differential distributions of erbB receptors in neurons and glia and the known functional differences between these kinases suggest that NRGs have distinct effects on these cells. The continued expression of NRGs and their erbB receptors in mature brain also implies that these molecules perform important functions in the brain throughout life.

Age Factors↗
PubMed2001

Neuregulin and ErbB receptor signaling pathways in the nervous system.

The neuregulins are a complex family of factors that perform many functions during neural development. Recent experiments have shown that neuregulins promote neuronal migration and differentiation, and regulate the selective expression of neurotransmitter receptors in neurons and at the neuromuscular junction. They also regulate glial commitment, proliferation, survival and differentiation. At interneuronal synapses, neuregulin ErbB receptors associate with PDZ-domain proteins at postsynaptic densities where they can modulate synaptic plasticity. How this combinatorial network - comprising many neuregulin ligands that signal through distinct combinations of dimeric ErbB receptors - elicits its multitude of biological effects is beginning to be resolved.

Amino Acid Sequence↗
PubMed2001

Molecular dissection of DNA sequences and factors involved in slow muscle-specific transcription.

Transcription is a major regulatory mechanism for the generation of slow- and fast-twitch myofibers. We previously identified an upstream region of the slow TnI gene (slow upstream regulatory element [SURE]) and an intronic region of the fast TnI gene (fast intronic regulatory element [FIRE]) that are sufficient to direct fiber type-specific transcription in transgenic mice. Here we demonstrate that the downstream half of TnI SURE, containing E box, NFAT, MEF-2, and CACC motifs, is sufficient to confer pan-skeletal muscle-specific expression in transgenic mice. However, upstream regions of SURE and FIRE are required for slow and fast fiber type specificity, respectively. By adding back upstream SURE sequences to the pan-muscle-specific enhancer, we delineated a 15-bp region necessary for slow muscle specificity. Using this sequence in a yeast one-hybrid screen, we isolated cDNAs for general transcription factor 3 (GTF3)/muscle TFII-I repeat domain-containing protein 1 (MusTRD1). GTF3 is a multidomain nuclear protein related to initiator element-binding transcription factor TF II-I; the genes for both proteins are deleted in persons with Williams-Beuren syndrome, who often manifest muscle weakness. Gel retardation assays revealed that full-length GTF3, as well as its carboxy-terminal half, specifically bind the bicoid-like motif of SURE (GTTAATCCG). GTF3 expression is neither muscle nor fiber type specific. Its levels are highest during a period of fetal development that coincides with the emergence of specific fiber types and transiently increases in regenerating muscles damaged by bupivacaine. We further show that transcription from TnI SURE is repressed by GTF3 when overexpressed in electroporated adult soleus muscles. These results suggest a role for GTF3 as a regulator of slow TnI expression during early stages of muscle development and suggest how it could contribute to Williams-Beuren syndrome.

Animals↗
PubMed2001

Leptin levels in diabetic and nondiabetic subjects.

The role of leptin in human pathophysiology elicits considerable interest in view of its potential role as a treatment tool for obesity and other insulin resistant states, like type 2 diabetes mellitus (T2DM). Leptin has been extensively studied in obese humans, and much less so in other pathologic conditions. Leptin level has been reported to correlate with percent body fat mass (%FM), fasting serum insulin (FPI), insulin sensitivity and blood pressure. The aim of this study was to compare the leptin concentration, and its relationship with some anthropometric and biochemical parameters related to insulin resistance in 140 moderately obese type 2 diabetics (T2DM) and 160 age and weight matched non-diabetic controls in order to get a better insight into the possible role of leptin in the metabolic abnormalities of diabetes. The leptin levels were lower in the diabetic population only when both sexes were combined (p < 0.05) and were higher in the females of both groups. Among the nondiabetics, the leptin levels appeared to be related to BMI, %FM, HDL and FPI, while this was not the case in the diabetics. After correction for BMI, leptin appeared to be correlated with the FPI levels only in the non-diabetic females. When plasma leptin was included in a multiple linear regression model with plasma leptin as a dependent variable, BMI, W:Hr and FPI levels were significantly related to leptin in the non diabetic population, while no relationship reached the level of statistical significance among the diabetics, with the exception of the borderline value for the FPI (p = .052). In conclusion, leptin levels were independent of any of the parameters examined in our diabetic population, possibly due to the progressive loss of the normal mechanisms of leptin regulation with advancing disease. Conclusive data can only be obtained from the longitudinal study of a cohort of newly diagnosed diabetic subjects.

Aged↗
PubMed2001

[Inguinal hernia prosthetic repair through the anterior approach].

BACKGROUND: Aim of this study is to compare the Lichtenstein's, Rutkow's and PHS techniques of inguinal hernia repair in terms of therapeutical efficacy and grade of acceptability, expressed in function of the complications, compliance and performance status of the patients. METHODS: The preliminary results of an ongoing prospective non-randomized study on the most frequently used techniques of inguinal hernia repair (PHS, Rutkow's, and Lichtenstein's) are reported. Sixty patients with primary inguinal hernia were divided into three homogeneous groups for age, gender, Gilbert's type of hernia, type of anesthesia, ASA class. The three groups underwent PHS, Rutkow's and Lichtenstein's inguinal hernia repairs, respectively. The end-points of the study were: operative time, intra- and postoperative pain, intra- and postoperative complications, patients compliance and performance status. RESULTS: The mean operative time were 40', 41' and 36' minutes for the PHS, Rutkow's and Lichtenstein's procedures, respectively. One of patients of the PHS group, five of the Rutkow's and none of those undergoing Lichtenstein's repair needed mild intraoperative sedation. Mild postoperative pain was recorded in 5% of the patients undergoing PHS repair and 10% undergoing Rutkow's repair. No intraoperative complications, difference in compliance and performance status were detected in the three groups. CONCLUSIONS: The conclusion is drawn that the PHS, Rutkow's and Lichtenstein's procedures for inguinal hernia repair are safe (no complications), effective and well accepted by the patients (85% of the patients expressed a very good judgement) although the Rutkow's repair seems more invasive. The appearance of a better trend, in patient's compliance and performance status when operated with the PHS technique, need to be confirmed in the future but, if it will be, this could became our first choice technique of repair for the medium and large hernia defect.

Adolescent↗
PubMed2000

The neuregulin receptor ErbB-4 interacts with PDZ-containing proteins at neuronal synapses.

Neuregulins regulate the expression of ligand- and voltage-gated channels in neurons and skeletal muscle by the activation of their cognate tyrosine kinase receptors, ErbB 1-4. The subcellular distribution and mechanisms that regulate the localization of ErbB receptors are unknown. We have found that ErbB receptors are present in brain subcellular fractions enriched for postsynaptic densities (PSD). The ErbB-4 receptor is unique among the ErbB proteins because its C-terminal tail (T-V-V) conforms to a sequence that binds to a protein motif known as the PDZ domain. Using the yeast two-hybrid system, we found that the C-terminal region of ErbB-4 interacts with the three related membrane-associated guanylate kinases (MAGUKs) PSD-95/SAP90, PSD-93/chapsyn-110, and SAP 102, which harbor three PDZ domains, as well as with beta(2)-syntrophin, which has a single PDZ domain. As with N-methyl-D-aspartate (NMDA) receptors, ErbB4 interacts with the first two PDZ domains of PSD-95. Using coimmunoprecipitation assays, we confirmed the direct interactions between ErbB-4 and PSD-95 in transfected heterologous cells, as well as in vivo, where both proteins are coimmunoprecipitated from brain lysates. Moreover, evidence for colocalization of these proteins was also observed by immunofluorescence in cultured hippocampal neurons. ErbB-4 colocalizes with PSD-95 and NMDA receptors at a subset of excitatory synapses apposed to synaptophysin-positive presynaptic terminals. The capacity of ErbB receptors to interact with PDZ-domain proteins at cell junctions is conserved from invertebrates to mammals. As discussed, the interactions found between receptor tyrosine kinases and MAGUKs at neuronal synapses may have important implications for activity-dependent plasticity.

Animals↗
PubMed2000

Roles of neuregulin in synaptogenesis between mossy fibers and cerebellar granule cells.

Neuregulins (NRGs), a large group of structurally related signaling proteins, are likely to have important roles in the development, maintenance and repair of the nervous system and other selected tissues. We have demonstrated, by using the major form of NRG cloned from the mouse cerebellum that both the soluble form and the membrane anchored form of NRG may serve different functions in synaptogenesis. The soluble form of NRG was produced by proteolytic cleavage of the membrane anchored form of NRG. The proteolytic cleavage was promoted by protein kinase activation. The cleaved form of NRG trans-synaptically regulated the expression of the NMDA (N-methyl-D-aspartate) receptor subunit NR2C as neurally-derived factors, whereas the membrane anchored form of NRG showed a homophilic binding activity between NRGbeta1s. In adult mice the membrane anchored form of NRG was concentrated in neuro-terminals of both granule cells and pontocerebellar mossy fibers. The fact that NRG can be functionally viewed as cell recognition molecules as well as neurotrophic agents suggests new possibilities for the important class of molecules.

Amino Acid Sequence↗
PubMed2000

Neuregulin found in cultured-sciatic nerve conditioned medium causes neuronal differentiation of PC12 cells.

The present work deals with the search and identification of the molecule or combination of molecules, present in a medium conditioned by cultured rat-sciatic nerves (CM), able to cause neuronal differentiation of PC12 cells. The molecular mass range of the active fraction, as well as the thermostability and heparin affinity of the active component found in previous work, all characteristics shared with neuregulin (NRG) family members, led us to search for a NRG protein in the CM. Nerves were previously cultured for 8 days and the CM collected every 24 h, the following 3 days. The CM was concentrated (30,000 NMWL) and fractionated by quaternary ammonium chromatography and Cibacron blue affinity chromatography. The most active fraction B1.2 was further characterized by heparin affinity chromatography, size exclusion HPLC, Western blotting and immunoprecipitation. Results reveal abundance of NRG mRNA in the cultured nerves, presence of a 54 kDa NRG protein in the CM that increases along fractionation, and progressive diminution of fraction B1.2 differentiation activity on PC12 cells by gradual removal of the NRG protein by immunoprecipitation. The abundance of Schwann cells and the lack of axons in the cultured nerves suggest Schwann cells as the main NRG source, to which fibroblasts and perineurial cells might contribute.

Animals↗
PubMed2000

Denervation induces a rapid nuclear accumulation of MRF4 in mature myofibers.

Muscle regulatory factor 4 (MRF4) is a member of the family of myogenic transcription factors, including MyoD, myogenin, and myf-5, that are necessary for the commitment and differentiation of mesoderm to skeletal muscle. Although the function of these transcription factors during embryonic development has been demonstrated, their role in adult muscle has remained elusive. Regulation of the MRF4 gene differs from the genes encoding the other myogenic factors in that its transcripts accumulate in neonatal muscle during maturation and continue to be expressed at relatively high levels in the adult. On the basis of its mRNA expression pattern, MRF4 has been suggested to regulate genes encoding adult contractile proteins and acetylcholine receptor subunits. To test this hypothesis, a specific antiserum was developed to study MRF4 protein expression in adult innervated and denervated muscle, because MRF4 mRNA levels increase by approximately threefold 1 day after nerve resection. By using three different immunohistochemical methods that vary widely in sensitivity, we were unable to detect MRF4 immunoreactivity in adult innervated muscles. The same results were obtained with another MRF4 antiserum generated independently. In contrast, any of these three immunologic techniques readily detected MRF4 immunoreactivity in myofiber and satellite cell nuclei of muscles denervated for 24 hours. The highest proportion of immunopositive nuclei (80%) was found 2-3 days after denervation. Immunoreactivity was no longer detectable by 14 days. There was no differential accumulation of MRF4 protein in the nuclei of satellite cells nor in sole plate (synaptic) nuclei at any time after denervation. No differences were found in the temporal accumulation of MRF4 in nuclei of type I and type II denervated myofibers, consistent with the similar distribution of MRF4 mRNAs in slow- and fast-twitch muscles. Our results are consistent with the lack of phenotype observed in the adult muscles of MRF4-null mutant mice observed by others and suggest that MRF4 may have important roles in the gene programs activated after denervation and during muscle regeneration.

3T3 Cells↗
PubMed1999

Gene regulation by patterned electrical activity during neural and skeletal muscle development.

Patterned neural activity modifies central synapses during development and the physiological properties of skeletal muscle by selectively repressing or stimulating transcription of distinct genes. The effects of neural activity are mostly mediated by calcium. Of particular interest are the cellular mechanisms that may be used to sense and convert changes in calcium into specific alterations in gene expression. Recent studies have addressed the importance of spatial heterogeneity or of temporal changes in calcium levels for the regulation of gene expression.

Action Potentials↗
PubMed1999

Fiber-type-specific transcription of the troponin I slow gene is regulated by multiple elements.

The regulatory elements that restrict transcription of genes encoding contractile proteins specifically to either slow- or fast-twitch skeletal muscles are unknown. As an initial step towards understanding the mechanisms that generate muscle diversity during development, we have identified a 128-bp troponin I slow upstream element (SURE) and a 144-bp troponin I fast intronic element (FIRE) that confer fiber type specificity in transgenic mice (M. Nakayama et al., Mol. Cell. Biol. 16:2408-2417, 1996). SURE and FIRE have maintained the spatial organization of four conserved motifs (3' to 5'): an E box, an AT-rich site (A/T2) that binds MEF-2, a CACC site, and a novel CAGG motif. Troponin I slow (TnIs) constructs harboring mutations in these motifs were analyzed in transiently and stably transfected Sol8 myocytes and in transgenic mice to assess their function. Mutations of the E-box, A/T2, and CAGG motifs completely abolish transcription from the TnI SURE. In contrast, mutation of the CACC motif had no significant effect in transfected myocytes or on the slow-specific transcription of the TnI SURE in transgenic mice. To assess the role of E boxes in fiber type specificity, a chimeric enhancer was constructed in which the E box of SURE was replaced with the E box from FIRE. This TnI E box chimera, which lacks the SURE NFAT site, confers essentially the same levels of transcription in transgenic mice as those conferred by wild-type SURE and is specifically expressed in slow-twitch muscles, indicating that the E box on its own cannot determine the fiber-type-specific expression of the TnI promoter. The importance of the 5' half of SURE, which bears little homology to the TnI FIRE, in muscle-specific expression was analyzed by deletion and linker scanning analyses. Removal of the 5' half of SURE (-846 to -811) results in the loss of expression in stably transfected but not in transiently expressing myocytes. Linker scanning mutations identified sequences in this region that are necessary for the function of SURE when integrated into chromatin. One of these sites (GTTAATCCG), which is highly homologous to a bicoid consensus site, binds to nuclear proteins from several mesodermal cells. These results show that multiple elements are involved in the muscle-specific activity of the TnIs promoter and that interactions between upstream and downstream regions of SURE are important for transcription in the context of native chromatin.

Animals↗
PubMed1998

Regulation of prothrombin, thrombin receptor, and protease nexin-1 expression during development and after denervation in muscle.

Prothrombin, thrombin receptor (ThR), and protease nexin-1 (PN-1) mRNA levels in mouse muscle were quantified using competitive reverse transcriptase-polymerase chain reaction during development and after denervation to examine the possible role of thrombin in activity-dependent synapse elimination at the neuromuscular junction. The results showed that the levels of prothrombin and ThR were maximal at birth and decreased by two orders of magnitude by postnatal day 20 (P20). The level of PN-1 mRNA was fairly constant during development except for a 4-fold to 5-fold downregulation at P10 and P15, the periods of maximal synapse elimination at the rodent neuromuscular junction. The expression of prothrombin mRNA in muscle at birth was 41-fold and 22-fold lower than those of ThR and PN-1, respectively, and the level of difference between prothrombin and PN-1 reached almost three orders of magnitude at adulthood. Denervation of adult muscle resulted in a reversal of the relative expression levels of the three genes. There were rapid 8-fold and 10-fold increases in prothrombin and ThR mRNA, respectively, and a 2-fold decrease in PN-1 mRNA. The changes in mRNA levels of the three genes after denervation indicated that these genes were regulated in a innervation-dependent manner and that nerve activity may play an important regulatory role in the expression of prothrombin, ThR, and PN-1. The concurrent regulation of prothrombin and ThR suggests that thrombin-mediated cellular activities in muscle may be affected via the activation of ThR. An elevated level of local thrombin or thrombin-like activity might result from the decreased inhibitory activity of PN-1 during the period of peak synapse elimination in muscle development.

Amyloid beta-Protein Precursor↗
PubMed1998

cDNA cloning and expression of a novel family of enzymes with calcium-independent phospholipase A2 and lysophospholipase activities.

Previous studies have suggested that activation of calcium-independent PLA2 (CaIPLA2) is an early event in cell death after hypoxic injury in proximal tubule cells. An approximately 28-kD CaIPLA2 with preferential activity toward plasmalogen phospholipids has been recently purified from rabbit kidney cortex (D. Portilla and G. Dai, J Biol Chem 271, 15,451-15,457, 1996). Their report describes the cloning of a full-length rat cDNA encoding CaIPLA2, using sequences derived from the purified rabbit kidney cortex enzyme. In addition, cDNA from rabbit kidney that encode the rabbit homologue of the enzyme and a closely related isoform were isolated. The rat cDNA is predicted to encode an approximately 24-kD protein, and each cDNA contains the sequence G-F-S-Q-G, which fits the active site consensus sequence G-X-S-X-G of carboxylesterases. Several lines of evidence (DNA sequence comparison, Southern blot analysis, and examination of the expressed sequence tag database) show that CaIPLA2 enzymes are encoded by a multigene family in rats, mice, rabbits, and humans. Northern analysis of various tissues from the rat indicated that the CaIPLA2 gene is ubiquitously expressed, with highest mRNA abundance observed in the kidney and small intestine. The rat CaIPLA2 cDNA, when expressed in a baculovirus expression system, and the purified rabbit kidney cortex protein exhibit both CaIPLA2 and lysophospholipase activities. The cloned CaIPLA2 cDNA are expected to aid in understanding the role of CaIPLA2 in cell death after hypoxic/ischemic cell injury.

Amino Acid Sequence↗
PubMed1996

Distinct N-methyl-D-aspartate receptor 2B subunit gene sequences confer neural and developmental specific expression.

Expression of the N-methyl--aspartate (NMDA) receptor 2B (NR2B) subunit is neural-specific and differentially regulated. It is expressed in the forebrain and in cerebellar granule cells at early postnatal stages and selectively repressed in the cerebellum after the second postnatal week, where it is replaced by the NR2C subunit. This switch confers distinct properties to the receptor. In order to understand the molecular mechanisms that differentially regulate the NR2B gene in the forebrain and cerebellum during development, we have isolated and characterized the promoter region of the NR2B gene. Two 5' noncoding exons and multiple transcription start sites were identified. Transcriptional analysis in transgenic mice reveals that an upstream 800-base pair region, which includes the first exon, is sufficient to direct neural-specific transcription. Developmental repression of the gene in the cerebellum requires additional regulatory elements residing in the first intron or second exon. Sequence elements that may participate in the regulation of the NR2B gene were identified by comparison to other neural genes. These studies provide insight into the molecular mechanisms regulating the switch of NMDA receptor subunit expression in the cerebellum, which ultimately account for the physiological changes in receptor function during development.

Animals↗
PubMed1996

Transcriptional control of muscle plasticity: differential regulation of troponin I genes by electrical activity.

Plasticity of the skeletal muscle phenotype can result from the selective repression and activation of gene expression in response to innervation patterns. Motoneurons, eliciting different patterns of depolarization, regulate the contractile properties of the myofibers they innervate by selectively activating expression of genes encoding fiber-type-specific (fast vs. slow) contractile proteins. We have analyzed the regulation of the troponin I slow (TnIs) and fast (TnIf) genes as a model to study the molecular mechanisms regulating fiber-type plasticity. We found that expression of the two TnI isoforms is downregulated by denervation. Moreover, TnI expression is upregulated by specific patterns of electrical activity [10 Hz vs. 100 Hz] used to depolarize muscle. We previously isolated the rat TnIs gene and demonstrated that regulatory sequences reside in its upstream region and second intron [Banerjee-Basu S, Buonanno A (1993), Mol Cell Biol 12:5024-5032]. Using transgenic mice, we show that the upstream region of the TnIs gene extending from -949 to +50 is sufficient to confer transcription specifically in slowtwitch muscles. Serial deletions of the TnIs upstream and intronic regions were generated in a CAT reporter vector to delineate transcriptional regulatory elements in transiently transfected Sol8 myotubes. Sequences necessary to confer the highest levels of TnIs transcription mapped to the upstream region between -0.95 and -0.72 kb, and to a 56 bp sequence located in the second intron. Comparison of the at sequence between -0.95 and -0.72 to the human TnIs gene identified a highly homologous region of 128 bp that we named the TnI SURE (slow upstream regulatory element). Alignment of these two SURE sequences with the quail TnI fast intronic regulatory element identified common motifs, namely, two A/T-rich sequences (A/T1 and A/T2) with homology to homeotic protein and MEF2 binding sites, a CACC box, an E box, and a novel motif (GCAGGCA) that we denoted the CAGG box. Mutation of either the A/T2 site, E box, or CAGG box practically abolish the SURE function in transfected myotubes; mutation of the A/T1 and CACC sites has a lesser effect. Using competitive electrophoretic mobility shift assays with nuclear extracts derived from Sol8 myotubes, we demonstrate specific binding to these motifs. The A/T1 and A/T2 sites are shown to form different complexes. The A/T2 site, which bears extensive homology to a MEF2 site, forms complexes that are super shifted by MEF2A antisera and that are competed by a consensus MEF2 site present in the MCK enhancer. Our results demonstrate that the linear arrangement of DNA sequence motifs is conserved in the regulatory elements of the TnI slow and fast genes and suggest that the interaction of multiple protein-DNA complexes are necessary for enhancer function.

Animals↗