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Biomedical subjects

G Stella

Publications and source records attributed to G Stella.

At least 19 recordsLinked to original sources

Regional reductions of gray matter volume in familial dyslexia.

An in vivo anatomic study of gray matter volume was performed in a group of familial dyslexic individuals, using an optimized method of voxel-based morphometry. Focal abnormalities in gray matter volume were observed bilaterally in the planum temporale, inferior temporal cortex, and cerebellar nuclei, suggesting that the underlying anatomic abnormalities may be responsible for defective written language acquisition in these subjects.

Adolescent↗

Long-term survival in Stuve-Wiedemann syndrome: a neuro-myo-skeletal disorder with manifestations of dysautonomia.

Stuve-Wiedemann syndrome (SWS) is a multiple congenital anomalies syndrome mostly considered to have an early lethality. Only few patients have been reported with long survival; therefore, the clinical phenotype with age has not yet been clearly characterized. We report on two patients with SWS aged 12 and 3 years who have both the osteodysplastic symptoms of the entity as well as autonomic nervous system symptoms resembling familial dysautonomia: lack of corneal reflex and neuropathic keratitis, absence of fungiform papillae, ulcerations of the tongue, paradoxical sweating at low temperature, patellar hyporeflexia, and progressive scoliosis. The clinical and radiological similarities between patients with SWS and patients with Schwartz-Jampel syndrome have led to the suggestion that these two syndromes are a single entity. SWS and Schwartz-Jampel syndrome type II are now indeed considered to be identical, but the radiographic phenotype of SWS long survivors such as the presently reported patients justifies the distinction between SWS and the classical type of Schwartz-Jampel syndrome. An increased number of lipid droplets in muscle fibers and decreased muscle mitochondrial enzyme activities have been found in one patient, confirming a previously reported association between SWS and respiratory chain abnormalities.

Abnormalities, Multiple↗

Cotrel-Dubousset instrumentation for the treatment of severe scoliosis.

In a multicentric study, 36 cases (40 curves) of severe scoliosis were analysed; 19 were idiopathic and 17 neurological, Cobb angles ranged from 70 degrees to 145 degrees, all had undergone three-rod Cotrel-Dubousset (CD) instrumentation. The correction on the frontal plane achieved more than 50% of the preoperative angle (53.9% for idiopathic curves and 55.6% for neurological ones). On the sagittal plane the pathological shape of the spine was reduced and distinctly ameliorated. In ten patients, the authors successfully applied a technique, alternative to the original one, which was based on the use of two or three screws in the lumbar area, one supplementary pedicle transverse claw on the cranial area and two rods connected by a domino, instead of a single rod (the longer one applied on the concave side). The main complications were: one case of infection, three of vascular compression of the duodenum, one of crank-shaft phenomenon and one laminar hook displacement. The excellent result achieved in both, idiopathic and neurological severe and stiff scoliosis shows the efficacy, reliability and versatility of CD three-rod instrumentation.

Adolescent↗

A novel missense mutation in the glycogen branching enzyme gene in a child with myopathy and hepatopathy.

We have identified a novel missense mutation in the gene for glycogen branching enzyme (GBE 1) in a 16-month-old infant with a combination of hepatic and muscular features, an atypical clinical presentation of glycogenosis type IV (GSD IV). The patient was heterozygous for a G-to-A substitution at codon 524 (R524Q), changing an encoded arginine (CGA) to glutamine (CAA), while the GBE1 gene on the other allele was not expressed. This case broadens the spectrum of mutations in patients with GSD IV and confirms the clinical and molecular heterogeneity of this disease.

1,4-alpha-Glucan Branching Enzyme↗

Kit signaling through PI 3-kinase and Src kinase pathways: an essential role for Rac1 and JNK activation in mast cell proliferation.

The receptor tyrosine kinase Kit plays critical roles in hematopoiesis, gametogenesis and melanogenesis. In mast cells, Kit receptor activation mediates several cellular responses including cell proliferation and suppression of apoptosis induced by growth factor deprivation and gamma-irradiation. Kit receptor functions are mediated by kinase activation, receptor autophosphorylation and association with various signaling molecules. We have investigated the role of phosphatidylinositol 3'-kinase (PI 3-kinase) and Src kinases in Kit-mediated cell proliferation and suppression of apoptosis induced both by factor deprivation and irradiation in bone marrow-derived mast cells (BMMC). Analysis of Kit-/- BMMC expressing mutant Kit receptors and the use of pharmacological inhibitors revealed that both signaling pathways contribute to these Kit-mediated responses and that elimination of both pathways abolishes them. We demonstrate that the PI 3-kinase and Src kinase signaling pathways converge to activate Rac1 and JNK. Analysis of BMMC expressing wild-type and dominant-negative mutant forms of Rac1 and JNK revealed that the Rac1/JNK pathway is critical for Kit ligand (KL)-induced proliferation of mast cells but not for suppression of apoptosis. In addition, KL was shown to inhibit sustained activation of JNK induced by gamma-irradiation and concomitant irradiation-induced apoptosis.

Animals↗

Gestures and words in early development of children with Down syndrome.

This study investigated the development of language and communication in children with Down syndrome (DS). More specifically, the aim was to examine the relations among verbal comprehension, verbal production, and gesture production in the very early stages of development. Forty children (age range: 10-49 months) with DS and 40 children with normal development (age range: 8-17 months) participated in this study. Children with DS came from two Italian health centers. The communicative and linguistic development of children with DS was measured by administering the Italian version of the MacArthur Communicative Development Inventory. The children with DS were severely delayed when compared with normally developing children in reaching the developmental stages. In such children a dissociation emerged between verbal comprehension and production, in favor of comprehension, whereas a synchronous development was found between vocal lexical comprehension and gestural production. The individual differences previously reported in these children are also evident in all domains examined. There were no significant differences between children with DS and typically developing controls matched for lexical comprehension on verbal production. However the two groups differed significantly in gestural development, suggesting a "gesture advantage" in children with DS compared with controls matched for word comprehension. Some possible reasons for this dissociative profile are discussed.

Age Factors↗

Surgical treatment of scoliosis associated with myelomeningocele.

Twenty-nine patients (mean age 12 years) with severe thoracolumbar and lumbar scoliosis due to myelomeningocele were treated by spinal fusion (7 by posterior arthrodesis with instrumentation, 3 by anterior arthrodesis with instrumentation, 19 by combined anterior and posterior fusion with instrumentation). Fusion was extended to the sacrum in 15 patients. Mean period of follow-up was 6.2 years. The average Cobb angle changes were as follows: thoracic and thoracolumbar curves preoperatively 86 degrees to 45 degrees at follow-up (the final average curve correction was 47%); lumbar curves preoperatively 97 degrees to 48 degrees at follow-up (the final average curve correction was 50%). Average pelvis obliquity changed from 26 degrees to 13 degrees at follow-up with an average correction of 49%. The combined anterior and posterior instrumentation and fusion gave the best correction of deformity (the final average thoracic and thoracolumbar curve correction was 55%; the final average lumbar curve correction was 61%). Independent of the method of stabilization, post-operative wound infection was a serious problem (24%). The combined fusion-instrumentation method reduced the rate of pseudoarthrosis to 14%.

Child↗

[Premedication with intranasal midazolam in children of various ages].

BACKGROUND AND AIM: To evaluate the efficacy of premedication with midazolam (mdz) administered using a nasal route compared to diazepam (dz) administered by mouth in children of different ages. EXPERIMENTAL DESIGN: A comparative type study was performed in randomly selected pediatric patients undergoing surgery. The study lasted 3 months. SETTING: Recovery room and operating theatre for Pediatric Surgery and ENT. PATIENTS: A total of 248 patients were studied, divided into 3 age groups: group A were aged under 2 years; group B were pre-school age and group C were school-age. OPERATIONS: Two subgroups were formed based on the premedication used: group M = 0.2 mg/kg of mdz using a nasal route on arrival in the operating unit; group D = 0.2 mg/kg of dz per os 45' before induction. PARAMETERS STUDIED: In addition to acceptance of treatment, which was deemed to be good, poor or refused, the authors evaluated the level of sedation (score from 5 to 1: awake-asleep), anxiety on entering SO (score from 1 to 4: none-excessive) and the level of collaboration during the induction of general anesthesia (score 1-4: excellent-nil). RESULTS: The nasal route was well accepted by 59% of patients in group A, 62% of group B and 97% of group C. Statistical analysis using Kruskall Wallis test showed significant differences in groups A and B between the two subgroups M and D for all the parameters studied, whereas there were no significant differences in group C. CONCLUSIONS: Premedication with mdz using a nasal route was safe and efficacious, above all in early and later infancy.

Adjuvants, Anesthesia↗

c-kit receptor signaling through its phosphatidylinositide-3'-kinase-binding site and protein kinase C: role in mast cell enhancement of degranulation, adhesion, and membrane ruffling.

In bone marrow-derived mast cells (BMMCs), the Kit receptor tyrosine kinase mediates diverse responses including proliferation, survival, chemotaxis, migration, differentiation, and adhesion to extracellular matrix. In connective tissue mast cells, a role for Kit in the secretion of inflammatory mediators has been demonstrated as well. We recently demonstrated a role for phosphatidylinositide-3' (PI 3)-kinase in Kit-ligand (KL)-induced adhesion of BMMCs to fibronectin. Herein, we investigated the mechanism by which Kit mediates enhancement of Fc epsilon RI-mediated degranulation, cytoskeletal rearrangements, and adhesion in BMMCs. Wsh/Wsh BMMCs lacking endogenous Kit expression, were transduced to express normal and mutant Kit receptors containing Tyr-->Phe substitution at residues 719 and 821. Although the normal Kit receptor fully restored KL-induced responses in Wsh/Wsh BMMCs, Kit gamma 719F, which fails to bind and activate PI 3-kinase, failed to potentiate degranulation and is impaired in mediating membrane ruffling and actin assembly. Inhibition of PI 3-kinase with wortmannin or LY294002 also inhibited secretory enhancement and cytoskeletal rearrangements mediated by Kit. In contrast, secretory enhancement and adhesion stimulated directly through protein kinase C (PKC) do not require PI 3-kinase. Calphostin C, an inhibitor of PKC, blocked Kit-mediated adhesion to fibronectin, secretory enhancement, membrane ruffling, and filamentous actin assembly. Although cytochalasin D inhibited Kit-mediated filamentous actin assembly and membrane ruffling, secretory enhancement and adhesion to fibronectin were not affected by this drug. Therefore, Kit-mediated cytoskeletal rearrangements that are dependent on actin polymerization can be uncoupled from the Kit-mediated secretory and adhesive responses. Our results implicate receptor-proximal PI 3-kinase activation and activation of a PKC isoform in Kit-mediated secretory enhancement, adhesion, and cytoskeletal reorganization.

Actins↗

p53 overexpression and human papillomavirus infection in transitional cell carcinoma of the urinary bladder: correlation with histological parameters.

Seventy-nine transitional cell carcinomas (TCCs) of the urinary bladder (25 grade 1, 22 grade 2, and 32 grade 3 tumours) were examined for p53 overexpression by immunohistochemistry with a monoclonal antibody and for human papillomavirus (HPV) infection by the polymerase chain reaction (PCR). Positive immunostaining for p53 was detected in 40.5 per cent of the cases; the percentage of positive cases was significantly lower in low-grade (G1 and G2) TCCs than in high-grade (G3) tumours (10.6 per cent vs. 84.4 per cent; P < 0.0001). The overall rate of HPV infection was 32.9 per cent; 20.3 per cent of the cases were positive for HPV 16, 3.8 per cent for HPV 18, and 8.9 per cent for both. Consensus primers as well as type-specific primers for HPV types 6, 11, and 33 failed to detect any additional case with HPV infection. The prevalence of HPV 16 and/or HPV 18 infection was significantly higher in low-grade than in high-grade tumours (44.7 per cent vs. 15.6 per cent; P = 0.0061). p53-positive cases were more common among papillary, deeply infiltrating tumours, and HPV-positive cases among papillary, non-infiltrating lesions. According to these data, p53 overexpression and HPV 16/18 infection are common findings in bladder TCC and there appears to be an inverse correlation of p53 overexpression and of HPV infection with tumour aggressiveness. The possibility of different molecular pathways in superficial low-grade and in invasive high-grade tumours is suggested.

Adult↗

[Solitary fibrous mesothelioma of the peritoneum. Considerations of a clinical case in our observation].

The authors report a case of so-called solitary fibrous peritoneal mesothelioma which was successfully operated on. Their case is compared with the few cases reported in the literature. Analysis of findings shows the fibrous peritoneal mesothelioma to be a solitary well defined tumor, generally of considerable size at the time of the diagnosis, very similar to the fibrous metothelioma of the pleura. It is believed to originate in the sub-mesothelial connective tissue. Surgery provides a definitive cure.

Adult↗

Differential roles of PI3-kinase and Kit tyrosine 821 in Kit receptor-mediated proliferation, survival and cell adhesion in mast cells.

The pleiotropic effects of the Kit receptor system are mediated by Kit-Ligand (KL) induced receptor autophosphorylation and its association with and activation of distinct second messengers, including phosphatidylinositol 3'-kinase (PI3-kinase), p21ras and mitogen-activated protein kinase (MAPK). To define the role of PI3-kinase, p21ras and MAPK in Kit-mediated cell proliferation, survival and adhesion in bone marrow-derived mast cells (BMMC), mutant Kit receptors were expressed in Wsh/Wsh BMMC lacking endogenous c-kit expression. The introduction of both murine Kit(S) and KitL (isoform containing a four amino acid insert) into Wsh/Wsh BMMC restored KL-induced proliferation, survival and adhesion to fibronectin, as well as activation of PI3-kinase, p21ras and MAPK, and induced expression of c-fos, junB, c-myc and c-myb mRNA. Substitution of tyrosine 719 in the kinase insert with phenylalanine (Y719F) abolished PI3-kinase activation, diminished c-fos and junB induction, and impaired KL-induced adhesion of BMMC to fibronectin. In addition, the Y719F mutation had partial effects on p21ras activation, cell proliferation and survival, while MAP kinase activation was not affected. On the other hand, Y821F substitution impaired proliferation and survival without affecting PI3-kinase, p21ras and MAPK activation, and induction of c-myc, c-myb, c-fos and c-jun mRNA, while KL-induced cell adhesion to fibronectin remained intact. In agreement with a role for PI3-kinase in Kit-mediated cell adhesion, wortmannin blocked Kit-mediated cell adhesion at concentrations known to specifically inhibit PI3-kinase. We conclude, that association of Kit with p85PI3-K, and thus with PI3-kinase activity, is necessary for a full mitogenic as well as adhesive response in mast cells. In contrast, tyrosine 821 is essential for Kit-mediated mitogenesis and survival, but not cell adhesion.

Animals↗

Littoral cell angiosarcoma of the spleen. Case report with immunohistochemical and ultrastructural analysis.

This report describes a case of a malignant vascular tumor of the spleen with the morphologic, immunologic, and ultrastructural features observed in splenic sinus-lining cells (littoral cells). Histological examination showed a well-differentiated neoplasm forming ectatic blood channels with intraluminal papillary fronds. Tumor cells displayed malignant nuclear features and hemophagocytosis. Solid neoplastic areas with mitotic figures were present. Ultrastructurally, the tumor cells showed the concomitant presence of lysosomes and Weibel-Palade bodies. Immunohistochemically, the tumor cells were positive for both endothelial (Factor VIII-AG, CD34) and histiocytic markers (cathepsin D, lysozyme, alpha-1-antichimotrypsin). Our results indicate that angiosarcoma may originate from all the vascular compartments of the spleen, including red-pulp sinuses, and may have morphologic and immunophenotypic similarities to littoral cell angioma, a recently described benign vascular tumor of the spleen.

Aged↗

A positively selecting thymic epithelial cell line lacks costimulatory activity.

The participation of costimulatory molecule interactions in positive selection of T lymphocytes was addressed by assessing the ability of a positively selecting thymic epithelial cell (TEC) line, 427.1, to stimulate allospecific CTL responses. Stimulation of H-2s spleen cells with the H-2b expressing 427.1 line does not result in the generation of cells capable of lysing H-2b target cell lines. The level of expression of MHC class I molecules by 427.1 is lower than that found in other stimulatory TEC lines. However, this finding does not account for the nonstimulatory phenotype. Up-regulation of MHC class I did not result in stimulation, and fusion of 427.1 cells with stimulatory TEC resulted in a line with low MHC class I molecule expression and stimulatory phenotype. The TEC line 427.1 does not express the costimulatory molecule B7/BB1, and transfection of the B7/BB1-encoding DNA results in expression of the molecule and conversion into a stimulatory phenotype, demonstrating directly that the non-stimulatory phenotype is a result of lack of costimulation. However, B7/BB1 expression does not improve the ability of 427.1 TECs to induce positive selection. Intrathymic injection of the B7/BB1 transfected, compared with mock transfected 427.1 cells, rescued fewer CD8+ mature thymocytes in beta 2-microglobulin negative mice. Therefore, unlike the peripheral T cell responses to Ag, positive selection of T cells in the thymus may not depend on the costimulation provided by the presenting cell.

Animals↗

Cervical adenocarcinomas express markers common to gastric, intestinal, and pancreatobiliary epithelial cells.

Frequency and pattern of expression of eight markers of gastric, intestinal, and pancreatobiliary duct epithelial cells have been investigated by histochemical and immunohistochemical techniques in 85 cases of cervical adenocarcinomas. M1, a mucin antigen, and Cathepsin E (CaE), an aspartic proteinase, markers of normal gastric superficial/foveolar epithelial cells, are expressed in 40 and 55 tumors, respectively. Periodic acid-concanavalin A-reactive mucin or Pepsinogen (PG) II, markers of gastric mucus neck and pyloric gland cells, are found in 24 tumors, 13 of which also express M1 and CaE. CAR-5 and M3SI, markers of intestinal mucin, are expressed in 68 and 12 tumors and DU-PAN-2, marker of normal pancreatobiliary duct cells, is found in 46 tumors. All but two tumors express at least one of the eight markers studied, none express PG I, marker of gastric chief cells. The different histologic subtypes of cervical adenocarcinomas expressed to a variable degree both gastrointestinal and pancreatobiliary markers. Only endocervical type tumors, however, showed the full spectrum of mucosal pyloric type differentiation, including the expression of PGII which is not present in any other histotype. A correlation between expression of gastroenteropancreatic markers and tumor grade is not apparent in our series.

Adenocarcinoma↗