Systematic Reconstruction of the Complete Two-Component Sensorial Network in Staphylococcus aureus.

In bacteria, adaptation to changes in the environment is mainly controlled through two-component signal transduction systems (TCSs). Most bacteria contain dozens of TCSs, each of them responsible for sensing a different range of signals and controlling the expression of a repertoire of target genes (regulon). Over the years, identification of the regulon controlled by each individual TCS in different bacteria has been a recurrent question. However, limitations associated with the classical approaches used have left our knowledge far from complete. In this report, using a pioneering approach in which a strain devoid of the complete nonessential TCS network was systematically complemented with the constitutively active form of each response regulator, we have reconstituted the regulon of each TCS of S. aureus in the absence of interference between members of the family. Transcriptome sequencing (RNA-Seq) and proteomics allowed us to determine the size, complexity, and insulation of each regulon and to identify the genes regulated exclusively by one or many TCSs. This gain-of-function strategy provides the first description of the complete TCS regulon in a living cell, which we expect will be useful to understand the pathobiology of this important pathogen.IMPORTANCE Bacteria are able to sense environmental conditions and respond accordingly. Their sensorial system relies on pairs of sensory and regulatory proteins, known as two-component systems (TCSs). The majority of bacteria contain dozens of TCSs, each of them responsible for sensing and responding to a different range of signals. Traditionally, the function of each TCS has been determined by analyzing the changes in gene expression caused by the absence of individual TCSs. Here, we used a bacterial strain deprived of the complete TC sensorial system to introduce, one by one, the active form of every TCS. This gain-of-function strategy allowed us to identify the changes in gene expression conferred by each TCS without interference of other members of the family.

[Surgical treatment of non-metastatic gastric GIST: two cases and review of the literature]. / Trattamento chirurgico dei GIST gastrici non metastatici: due casi significativi e revisione della letteratura.

Gastro-Intestinal Stromal Tumors (GISTs) represent an evolving field in oncological surgery and must be approached with specific prognostic and therapeutic criteria. In the GIST's suspicion the surgeon has to consider all the therapeutic possibilities, also for the impossibility to predict the biological behaviour and the aggressiveness of the tumor. The presence of a GIST has to be suspected in patients observed for gastrointestinal bleeding, when another pathology isn't demostrable. Surgical strategy must consider a limited resection as the best treatment, differently from what we do for adenocarcinoma. The extension of the resection can changes, regarding tumor volume and position, from extremely invasive surgery to laparoscopic operations with a partial removal of the gastric wall. Lymphadenectomy is not indicated because these tumors rarely spread to the nodes. We present the clinical case of two patients observed for gastrointestinal bleeding and with preoperative diagnostic suspicion of GIST, submitted to surgical resection. In the first case we performed a superior polar gastrectomy with esofago-gastric anastomosis for the mass proximity to the cardias. In the second patient the intervention has been a limited resection of the fundus of stomach including the tumor.

[A case of amputation neuroma of the bile duct following video-laparoscopic cholecystectomy]. / A proposito di un caso di neuroma d'amputazione della via biliare dopo colecistectomia laparoscopica.

We report a case of neuroma of the common hepatic duct arising five years after cholecystectomy (laparoscopic then converted in laparotomy). A 73-years-old patient was admitted for obstructive jaundice. Ultrasonography, TC and cholangiography showed a nodular lesion of the common hepatic of 1 cm in diameter, causing a regular and important stenosis of the main bile duct. Histologic examination demonstrated neuroma. By the analysis of this and 42 other previously published cases, the following features of bile duct neuroma were outlined: 1) variable interval between cholecystectomy and the onset of jaundice (2 months to 40 years); 2) the same incidence after laparoscopic or laparotomic cholecystectomy; 3) the generally complicated postoperative course after first surgical approach; 4) the various localizations on the biliary tree (cystic, main bile duct, intrahepatic ducts); 5) the circumstances of onset are almost the same (obstructive jaundice); 6) the histologic examination is mandatory for a correct diagnosis; and 7) the best treatment is resection of the bile duct tract involved in neuroma and reconstruction of biliary tree with hepaticojejunostomy.

[Gastric metastasis from melanoma. Report of 2 surgically treated cases]. / Metastasi gastriche da melanoma. A proposito di due casi trattati chirurgicamente.

Metastatic disease involving the gastrointestinal tract is a rare pathology and melanoma is the extra-intestinal neoplasm more frequently concerned. Two cases of gastric metastases, revealed by symptoms of upper gastrointestinal bleeding, are reported. In the first case the disease-free interval, after excision of the primary lesion located in the right lower limb, was 13 years; in the second case the primary lesion remained unknown, although it probably originated from a giant congenital nevus of the left foot. Both patients had been affected before by inguinal nodes metastases, treated by radical groin lymphadenectomy; the concomitant multiple metastases to other sites (adrenal glands, retro-peritoneum, liver, lung, small bowel, brain, ovaries) limited surgery to a likely prospect of palliation, conditioning an unfavourable prognosis. Resection of gastrointestinal metastases is justified for the relief of intestinal hemorrhage (as in these reported cases), perforation and obstruction, even if treatment of single non-complicated lesions can have a curative intent. The conclusion is drawn that more aggressive diagnostic and staging procedures are indicated for the early detection of gastrointestinal metastases whenever non-specific abdominal symptoms and a history of melanoma are present.

Unusual localizations of hydatid disease: a 18 year experience.

The Authors report their experience with rare localizations of hydatid cysts during a period of 18 years. In 8 patients (14%) other organs than liver or lungs were involved: in particular one case of hydatid cyst of the spleen, one of the pancreatic area and one of the soft tissue of the back presented as primary locations. In 5 patients the disease of the liver was associated to hydatid cysts in other sites: 3 multiple peritoneal localizations, one in the abdominal rectus muscle and one of the gallbladder. Four cases (10% of the patients with liver disease) of cyst ruptures in the biliary tree were reported. In all cases differential diagnosis was more challenging than usual, but imaging devices combined with immunobiological tests could solve the diagnostic problem. Surgical treatment was as radical as possible considering the benign character of the disease. Postoperative results were satisfying: no recurrence but one was found at follow up.