Microstructural mechanical study of a transverse osteon under compressive loading: The role of fiber reinforcement and explanation of some geometrical and mechanical microscopic properties.

This Finite Element study aims at understanding the transverse osteon as a composite microstructure, and at differentiating the actions of each of its main components and their interactions. Three components of the osteon have been distinguished: the lamellae mineral-collagen matrix, the lamellae mineral-collagen reinforcement fibers and the Haversian canal content made of intracortical fluid and soft tissues. Numerical compression experiments have been performed, varying the microstructure properties. Our results show that fiber reinforcement of transverse osteons is only efficient at resisting dynamic compressive loadings, but that the improvement of the static compressive properties is very poor. Furthermore, the modeled stress distribution within the matrix and reinforcement fibers may explain why transverse osteons are often limited to a small number of lamellae (<8) and why internal lamellae could be stiffer than external ones.

Tissue ghrelin level and gastric emptying rate in adult patients with celiac disease.

Celiac disease (CD) patients show a number of gastrointestinal motor abnormalities. Ghrelin, a gastric peptide implicated in short-term feeding control and long-term body weight regulation, has been recently considered a key regulator of gastric motility. The aim of this study was to evaluate the gastric emptying rate of solids and the density of ghrelin-immunopositive cells in adult CD patients before and at least 1 year after starting a gluten-free diet. Twenty CD patients (M 8/F 12; mean age 36 years) and 10 controls underwent endoscopy with gastric and duodenal biopsies and 13C-octanoic acid breath test to measure gastric emptying of solids. Celiac disease patients repeated the protocol at least 1 year after starting gluten-free diet. Ghrelin tissue levels were evaluated by immunohistochemistry on gastric mucosa specimens. Gastric emptying time was normal in all control subjects (t(1/2) = 89 +/- 16 min) while it was delayed in CD patients prior to gluten-free diet (t(1/2) = 252 +/- 101 min; P < 0.005). The mean number of ghrelin-positive cells/field (x 400) was 14.4 +/- 2.7 in controls and 25.3 +/- 5.7 in CD patients respectively (P < 0.0001). Gluten withdrawal was effective in normalizing gastric emptying time in all CD patients (97 +/- 14 min; P < 0.0001) and resulted in a significant reduction of the density of ghrelin-immunopositive cells (19.8 +/- 5.4; P < 0.0001). The density of ghrelin-positive cells correlated directly with the degree of duodenal damage (P < 0.001) and inversely with the body mass index of CD patients (P < 0.0001). However, in neither CD patients nor controls, a correlation between tissue ghrelin levels and gastric emptying rate was detected. In conclusion, tissue ghrelin level does not correlate with gastric emptying rate in adult CD patients and in controls.

A clinical-morphological study on cholestatic presentation of nonalcoholic fatty liver disease.

To determine the association among the clinical, biochemical, and histological features of cholestasis, we analyzed all the relevant data of the patients recorded in our non-alcoholic fatty liver disease (NAFLD) database. We selected 20 NAFLD patients with abnormal transaminase levels, with both alkaline phosphatase >500 U/L and gamma-glutamyl transpeptidase >250 U/L. Their histological features were compared with those of a group of patients with NAFLD matched for sex, age, and body mass index and of a group of patients matched for sex, body mass index and histological NAFLD grading/staging. Cases and controls satisfied, on histology, the criteria for NASH. The presence of cholestasis in our patients was correlated with injury of the bile duct epithelium, characterized by cholangitis, swelling, variable bile duct loss, and bile stasis. Compared to NAFLD patients of similar age, sex, and body mass index, the cholestatic group had total and severe histological liver impairment. When we analyzed the group of patients histologically identified on the basis of identical stage and grade severity, we could not find any evidence of significant bile damage, compared to cases, despite the control group's significantly older age. NAFLD patients with biochemical cholestasis have a histological picture of bile damage; they have more advanced histological impairment than patients matched for age, sex and body mass index.

Relationship between MPQ and VAS in 962 patients. A rationale for their use.

BACKGROUND: 1) To analyse the information provided both by the Visual Analogue Scale (VAS) and by the McGill Pain Questionnaire (MPQ) in a cross-sectional study with patients affected by different kinds of pain and to study the relationship between VAS and MPQ scores in the same patient sample. METHODS: 962 patients affected by different kinds of pain (i.e. neuropathic pain, acute post-traumatic pain, chronic musculo-skeletal pain, headache, and cancer pain) were enrolled into the study during the first visit for pain management. The horizontal 10cm VAS and the Italian version of the MPQ were administered. RESULTS: VAS scores proved to be significantly lower in acute post traumatic and in chronic musculo- skeletal pain compared to headache and neuropathic pain. VAS scores were signi- ficantly higher in neuropathic pain compared to cancer pain. MPQ total score (Pain Rating Index, PRI) related to neuropathic pain was significantly higher than scores reported in the other pain groups, with the exception of cancer pain. Cancer pain MPQ total score was higher than acute post-traumatic and chronic musculo-skeletal PRI pain scores. Different patterns of MPQ dimensions emerged within each pain group. The association between VAS and PRI, analysed by means of stepwise multiple regression analyses was significantly different among the groups (p<0.0001). The percentage of VAS variance explained by MPQ PRI score ranged from 6% (headache) to 32% (neuro-pathic pain). CONCLUSIONS: Several differences emerged among the pain groups. VAS and MPQ resulted to address pain aspects only partially overlapping. In some clinical conditions (headache and cancer) the MPQ can provide more detailed and clinically useful information about patients' pain experience.

RB2/p130 gene-enhanced expression down-regulates vascular endothelial growth factor expression and inhibits angiogenesis in vivo.

Angiogenesis is an essential step in the progression of tumor formation and development. The switch to an angiogenetic phenotype can occur as a distinct step before progression to a neoplastic phenotype and is linked to genetic changes such as mutations in key cell cycle regulatory genes. The pathogenesis of the angiogenetic phenotype may involve the inactivation of tumor suppressor genes such as the "guardian of the genome," p53, and the cyclin-dependent kinase inhibitor p16. Retinoblastoma family member RB2/p130 encodes a cell cycle regulatory protein and has been found mutated in different tumor types. Overexpression of RB2/p130 not only suppresses tumor formation in nude mice but also causes regression of established tumor grafts, suggesting that RB2/p130 may modulate the angiogenetic balance. We found that induction of RB2/p130 expression using a tetracycline-regulated gene expression system as well as retroviral and adenoviral-mediated gene delivery inhibited angiogenesis in vivo. This correlated with pRb2/p130-mediated down-regulation of vascular endothelial growth factor protein expression both in vitro and in vivo.

Mutations in the retinoblastoma-related gene RB2/p130 in primary nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an endemic cancer in southern China and northern Africa, and its pathogenesis is not yet well defined at the molecular level. Although the involvement of p53 and of the retinoblastoma gene (RB/p105) in NPC has been well studied, there is paucity of mutational data regarding the retinoblastoma-related gene RB2/p130 in primary tumors and particularly in NPC. We have shown previously that RB2/p130 could be rearranged in a nasopharyngeal cell line. In the present study, we screened by single-strand conformation polymorphism and sequence analysis the retinoblastoma-related gene RB2/p130 for mutations within exons 19-22. Mutations in the RB2/p130 gene were detected in 3 of 10 primary human NPCs from Northern Africa (30%). These findings, along with previous data showing that genetic replacement of RB2/p130 restores a normal growth pathway in the nasopharyngeal cell line Hone-1, strengthen the hypothesis that genetic changes of RB2/p130 may be involved in the development and/or progression of nasopharyngeal cancer and suggest that RB2/p130 could be considered a tumor suppressor gene and may be a candidate for novel gene therapeutic approaches for NPC.

Regulatory functions of Cdk9 and of cyclin T1 in HIV tat transactivation pathway gene expression.

HIV-1 gene expression relies upon a complex machinery that is primarily controlled by two viral regulatory proteins, Tat and Rev. Rev is involved in regulating post-transcriptional events of HIV-1 gene expression. The Tat protein transactivates transcription from the HIV-1 5' long terminal repeat (LTR) and acts in synergy with specific cellular factors. Recently, it has been shown that one set of these cellular factors is a protein kinase activity termed TAK (Tat-associated kinase), which activates transcription by hyperphosphorylation of the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II. TAK also enhances transcription of HIV-2, together with the retroviral transactivator, Tat-2. The TAK activity appears to be related to the CTD kinase P-TEFb, which stabilizes transcription elongation of many genes and was originally isolated from Drosophila extracts. Both TAK and P-TEFb contain at least two subunits: the cyclin-dependent kinase, CDK9 (PITALRE), the catalytic subunit, and the regulatory subunit, cyclin T1. CDK9 and cyclin T1 are ubiquitous factors that affects many cellular processes, including cell differentiation and apoptosis. The involvement of TAK in HIV-1 and HIV-2 gene expression is an important aspect in the biology of these two retroviruses, and may lead to the development of novel antiretroviral drugs and/or gene therapy approaches for the treatment of patients with AIDS.

Pathological relevance of epithelial and mesenchymal phenotype plasticity.

Epithelium and mesenchyme, two tissue types virtually found in every organ, are endowed with fundamentally different functional properties. Active motility, a capability that is limited to the mesenchymal repertoire, is the principal characteristic that distinguishes them. During embryonic development, conversions from epithelium to mesenchyme and from mesenchyme to epithelium normally occur, allowing morphogenetic processes and tissue remodelling to take place. However, there is now increasing evidence that the modulation between the epithelial and the mesenchymal phenotypes is not limited to embryonic life. Indeed, the pathogenesis of some adult diseases seems to implicate an inappropriate activation of this change. On the other hand, failure of normally occurring embryonic epithelial-mesenchymal interconversions could result in the development of some pathologies. It is now possible to study some molecular events underlying these phenotype transitions, since several biological agents implicated in the epithelial-mesenchymal interconversion, such as growth factors, extracellular matrix components and their receptors, transcription factors and oncogenes have been identified. The malignant potential of some oncogenes seems to express itself through the disruption of the mechanisms involved in the maintenance of the epithelial phenotype while, on the other hand, some observations suggest the existence of regulatory genes able to counteract the action of oncogenes by restoring epithelial characteristics. Therefore, the manipulation of the tissue phenotype could represent a novel strategy for the prevention and treatment of diseases in the future.

[Co-trimoxazole administration: a rare cause of hypoglycemia in elderly persons]. / Prise de co-trimoxazole: une cause rare d'hypoglycémie chez la personne âgée.

We report a case of severe hypoglycaemia following co-trimoxazole therapy. An 88-year-old woman was admitted with urinary tract infection and treated with co-trimoxazole (960 mg bid). Seven days after initiation of the treatment she became comatose. Blood sugar was 1.3 mmol/l and C-peptide at the upper limit of normal range. Glucose infusion restored normal consciousness and no hypoglycaemia recurred after interruption of co-trimoxazole therapy. Advanced aged was the only risk factor identified. Other risk factors described in previous case reports are renal failure, poor nutritional state and high doses of co-trimoxazole.

Prognostic value of p53 in non-small cell lung cancer: relationship with proliferating cell nuclear antigen and cigarette smoking.

p53 mutations are among the most frequent genetic alterations reported in human lung cancer. Although the prognostic value of altered p53 expression is still debated, it is accepted widely that estimation of the proliferation rate has an important prognostic role. Moreover, an association between certain types of human lung cancers and tobacco use is well known. Drawing from this background, we investigated the immunohistochemical expression of mutant oncogenic p53 protein, and related it to the smoking history of 61 patients with non-small cell lung carcinoma (NSCLC) and to the expression pattern of proliferating cell nuclear antigen (PCNA), which is considered to be an important negative prognostic factor in several neoplasms. We found p53 overexpression in 22 (36.1%) specimens, including 16 squamous carcinomas (41%) and six (27.2%) adenocarcinomas. PCNA nuclear staining was detected in 98.4% of the specimens, and a significantly higher PCNA expression score was found in all of the p53-positive samples. When the patient survival time was compared, p53 accumulation had a statistically significant negative prognostic value (P < .001). This was supported by a Kaplan-Meier survival percentage plot of immunohistochemically p53-undetectable specimens and p53-detectable specimens. These latter patients had a greatly reduced survival time. A relationship was established between p53 immunohistochemical detection and the smoking history of the patients. None of the specimens from the nonsmoking patients expressed immunohistochemically detectable p53 protein. Altered p53 expression was detected in 40.7% of smoking patients. Our findings support the hypothesis of involvement of p53 mutations in tobacco-induced carcinogensis and indicate that altered p53 expression plays an important prognostic role in NSCLC in smokers.

[Benign ulcers of the cecum]. / Le ulcere benigne del cieco.

Benign ulceration of the cecum is an uncommon lesion that was originally described by Cruveilhier in 1832. Etiology is unknown and symptomatology not pathognomonic. Pre-operative and intraoperative diagnosis is rare and difficult. Definitive diagnosis is usually obtained by histologic evaluation of the surgical specimen after a right hemicolectomy performed for a suspect of a neoplasm of the cecum. The authors present 7 cases of cecal ulcers and suggest that preoperative diagnosis may be due after a colonoscopy with biopsy. This examination may be performed only in that cases that appear without symptoms of acute abdomen. The authors suggest also to perform right hemicolectomy.

Phenotypic features and secretory pattern of alveolar macrophages in atopic asthmatic patients.

The aim of this study was to evaluate by cytofluorimetry, the phenotype and the activation of alveolar macrophages (CD14; CD33; CD44; CD54; CD23; HLA-DR) and, by radioimmunoassay, the "in vivo and in vitro" macrophage secretory pattern (IL-1 alpha; IL-1 beta; IL6; IL8; PGE2; PGD-1 alpha; TXB2; LTB4) in atopic patients with mild asthma in intercritical phase and with bronchial hyperreactivity (PD20 FEV1 = 377 +/- 262.8 micrograms). In asthmatic patients we have demonstrated that the number of cells recovered in BALF expressing the phenotypic features (CD14; CD33; HLA-DR; CD23; CD44; CD54) was larger than in control subjects. By analysing the culture medium of unstimulated and LPS-stimulated alveolar macrophages from asthmatic and normals we have demonstrated a greater production of IL-1 beta (p = 0.005) and IL-8 (p = 0.005) in the first group than in one second, as confirmed by a Wilcoxon test. Concerning the secretory pattern in BALF of asthmatic patients we obtained similar results, showing a significant IL-1 beta (p = 0.005) and IL-8 (p = 0.002) increase suggesting a persistent cellular activation. On the contrary we could not show any significant increase of IL-1 alpha (p = 0.31) and IL-6 (p = 0.22). The cellular activation was confirmed by increased levels of different chemical mediators such as TXB2 (p = 0.005); LTB4 (p = 0.004); PGE2 (p = 0.007); PGF-1 alpha (p = 0.008) which were recovered from BALF of asthmatic patients compared to normal subjects. In conclusion alveolar macrophages play an important role in the pathogenesis of asthma because of the presence of cytokines and mediators in BALF and in the supernatant of alveolar macrophage cultures.

[Role of splenectomy in Chediak-Higashi syndrome in its accelerated phase]. / Ruolo della splenectomia nella sindrome di Chediak-Higashi (SCH) in fase accelerata.

Chediak-Higashi (C.H.S.) syndrome is a rare immunodeficiency, due to defective granulocyte activity. The syndrome is characterized by large inclusion bodies in the leukocytes, albinism, photophobia, nystagmus, and recurrent infections. Some patients develop hepatosplenomegaly, lymphadenopathy, pancytopenia and widespread organ infiltrates with mononucleated cells. This phase is called "accelerated (or lymphoma-like syndrome) phase". A 5 years old girl with C.H.S. in accelerated phase received initially medical treatment without improvement. A splenectomy was performed to remove the hypersplenism and the mechanical compression of the spleen on the gut. Few days after the splenectomy the fever and the pancytopenia disappeared. The pathological examination of the spleen showed multiple intraparenchymal abscesses. Unfortunately, six months after the operation, she died after an acute episode of pneumonia, with normal hematological pattern. The splenectomy may play a role in the "accelerated phase" of C.H.S., but new treatments (bone marrow transplantation) are necessary to remove the basic disease.