The suppression of star formation by powerful active galactic nuclei.

The old, red stars that constitute the bulges of galaxies, and the massive black holes at their centres, are the relics of a period in cosmic history when galaxies formed stars at remarkable rates and active galactic nuclei (AGN) shone brightly as a result of accretion onto black holes. It is widely suspected, but unproved, that the tight correlation between the mass of the black hole and the mass of the stellar bulge results from the AGN quenching the surrounding star formation as it approaches its peak luminosity. X-rays trace emission from AGN unambiguously, whereas powerful star-forming galaxies are usually dust-obscured and are brightest at infrared and submillimetre wavelengths. Here we report submillimetre and X-ray observations that show that rapid star formation was common in the host galaxies of AGN when the Universe was 2-6 billion years old, but that the most vigorous star formation is not observed around black holes above an X-ray luminosity of 10(44) ergs per second. This suppression of star formation in the host galaxy of a powerful AGN is a key prediction of models in which the AGN drives an outflow, expelling the interstellar medium of its host and transforming the galaxy's properties in a brief period of cosmic time.

Submillimetre galaxies reside in dark matter haloes with masses greater than 3 × 10(11) solar masses.

The extragalactic background light at far-infrared wavelengths comes from optically faint, dusty, star-forming galaxies in the Universe with star formation rates of a few hundred solar masses per year. These faint, submillimetre galaxies are challenging to study individually because of the relatively poor spatial resolution of far-infrared telescopes. Instead, their average properties can be studied using statistics such as the angular power spectrum of the background intensity variations. A previous attempt at measuring this power spectrum resulted in the suggestion that the clustering amplitude is below the level computed with a simple ansatz based on a halo model. Here we report excess clustering over the linear prediction at arcminute angular scales in the power spectrum of brightness fluctuations at 250, 350 and 500 µm. From this excess, we find that submillimetre galaxies are located in dark matter haloes with a minimum mass, M(min), such that log(10)[M(min)/M(⊙)] = 11.5(+0.7)(-0.2) at 350 µm, where M(⊙) is the solar mass. This minimum dark matter halo mass corresponds to the most efficient mass scale for star formation in the Universe, and is lower than that predicted by semi-analytical models for galaxy formation.

Routine laparoscopic cholecystectomy after endoscopic sphincterotomy for choledocholithiasis in octogenarians: is it worth the risk?

BACKGROUND: No unanimous consensus has been reached as to the need for routine laparoscopic cholecystectomy (LC) after endoscopic sphincterotomy (ES) for choledocholithiasis in very elderly patients, who are considered as high-risk subjects for surgery. METHODS: From 1991 through 1997, 170 patients were referred to undergo preoperative ES and routine LC for common bile duct (CBD) stones. The results for 27 patients (age 80 years or older) were compared with those achieved for younger patients. Successively, in a retrospective case-control study, the results for the selected patients were compared with those for 27 very elderly patients who underwent endoscopic retrograde cholangiopancreatography (ERCP), but did not receive LC. The mean follow-up period was 126 months. RESULTS: Octogenarians showed longer surgery time (79 vs 51 min) and postoperative hospital stay (2.8 vs 1.2 days), as well as more early low-grade complications (15% vs 3%), whereas there were no differences in conversion rate or serious complications. Recurrent symptoms or complications developed in 48% of octogenarians not undergoing routine LC, and 30% finally needed surgery. One patient in the control group died after emergency cholecystectomy for acute cholecystitis. The results of surgery were significantly poorer for the control group. CONCLUSIONS: Although a "wait-and-see" policy allowed two-thirds of LCs to be avoided in octogenarians, biliary-related events developed for every second patient, often requiring delayed surgery, with poorer results. Sequential treatment (ES followed by elective LC) is a safe procedure for octogenarians, and should be considered as a standard, definitive treatment for cholecystocholedocholithiasis even after the age of 80 years.

Anorectal reconstruction by electrostimulated graciloplasty as part of abdominoperineal resection.

AIMS: To report the outcomes of anorectal reconstruction by electrostimulated graciloplasty as part of abdominoperineal resection, on data prospectively collected over 10 years. PATIENTS AND METHODS: Twenty-three abdominoperineal resections were associated to coloperineal pull through, double graciloplasty and loop abdominal stoma. Fifteen patients also received an implantable pulse generator, either for unsatisfactory result after external-source intermittent electrostimulation and biofeedback (five cases) or during graciloplasty (10 cases). Follow-up was to a maximum of 10 years. Functional outcome was followed up in sixteen patients who underwent stoma takedown. RESULTS: Mean actuarial survival at 5 years was 72.3%. Satisfactory results (score < or =8) occurred in 75% of patients (three without and 13 with stimulator) in the early stages, decreasing to 57% at 1 year and gradually increasing up to 100% at 5 years and over. CONCLUSIONS: Total anorectal reconstruction yields a good functional outcome over time. Thus, despite, and because of, a high complication rate and a great drain on resources, it should be considered a suitable procedure only for selected, strongly motivated patients.

Rectal cancer in anorectal malformation with rectovestibular fistula: sphincter-restoring surgery by anterior resection and dynamic vaginoanograciloplasty.

PURPOSE: The aim of this study was to describe and discuss the anosphincter-restoring procedure adopted in an adult patient with rectal cancer, affected by anorectal atresia and rectovestibular fistula not previously treated. METHODS: After anterior resection and transverse dissection of the rectovaginal septum, a straight double-staple low colorectal anastomosis was performed. A subcutaneous tunnel was extended from the inter-rectovaginal space, surrounding the pseudoanal orifice. The tunnel housed a left gracilis muscle arranged counter-clockwise and connected to an implanted stimulator. The vaginal and anorectal flaps were sutured longitudinally, thereby spacing out the two orifices and creating an anorectal angle. A temporary loop right colostomy was performed. RESULTS: The postoperative course was uneventful. After continuous electrostimulation training and colostomy takedown, the patient had improved continence (stimulator on) and normal defecation (stimulator off). CONCLUSIONS: The solution described seemed a suitable alternative to a pull-through procedure, which would have involved a colocutaneous anastomosis and the loss of the anorectal sensory function. Any previous anal transposition or pull-through procedures would have prevented the saving of the pre-existing "anus," because of the interruption of the residual mesenteric vascular supply to the anorectal remnant secondary to mesorectal excision.

c-Myc expression in human anagen hair follicles.

The hair follicle represents a very attractive organ system for studying the precise balance between cell proliferation, growth, differentiation, and death of cells, because it periodically and regularly regenerates, retaining its morphogenetic signals throughout its life. One of the most intriguing oncogenes which is able to induce both cell growth and apoptosis, depending upon the environmental conditions, is c-myc. The aim of the present study was to investigate its presence and localization in human hair follicles by immunohistochemistry and immunofluorescence. Our observations demonstrated the consistent presence of two clusters of c-Myc-expressing cells in anagen follicles, located in two annular regions of the inner root sheath, at the border between cells characterized by putative trichohyalin granules and cells which are keratinized. The lower group belongs to Henle's layer, while the upper group belongs to Huxley's layer. c-Myc oncoprotein seems to favour apoptosis/differentiation and may be a marker for terminal differentiation of trichocytes, at least in the inner root sheath. Our findings agree with the interpretation that the complex morphology of the hair follicle reflects its complex function; the extrusion of a highly organized multicellular structure, the hair shaft, driven by another highly organized multicellular structure, the inner root sheath.

Diverticulitis of the caecum and ascending colon: an unavoidable diagnostic pitfall?

PURPOSE: The infrequency of right-sided colonic diverticulitis prompted this presentation of our experiences, with emphasis on the diagnostic aspects. PATIENTS AND METHODS: Charts and documentation regarding 20 patients who underwent surgery for diverticulitis of the caecum and/or ascending colon over 22 years were reviewed. RESULTS: Eleven patients underwent pre-operative instrumental examinations: right-sided diverticulitis was recognized in five patients (two by barium enema, two by both ultrasonography and computerized tomography, one by all three examinations) and was suspected in another four. All diagnoses on merely clinical grounds--acute appendicitis in 10 patients and perforated peptic ulcer in one--were erroneous. Surgery consisted of 13 right standard or limited hemicolectomies, six conservative procedures and one Mickulicz' operation and subsequent right hemicolectomy. No operative deaths or long-term failures were reported. CONCLUSIONS: In the presence of clinical features atypical of acute appendicitis, right-sided colonic diverticulitis should be taken into account; pre-operative instrumental examinations might increase diagnostic accuracy, thereby leading to a more correct therapeutic approach.

[Biopsy of sentinel lymph nodes in the treatment of breast carcinoma: experience of the Surgery Department of the Hospital of Parma]. / La biopsia del linfonodo sentinella nel trattamento del carcinoma mammario: esperienza del Dipartimento Chirurgico dell'Azienda Ospedaliera di Parma.

Radical axillary nodes dissection in breast cancer is a standard for a correct staging, unfortunately this approach can cause several unpleasant sequelae and complications. Sentinel node biopsy applied to breast tumors could be a good option for predicting axillary nodes status avoiding complete dissection. The aim of this work is to report our experience with sentinel node biopsy during a period of 18 months. One hundred and nine patients with an infiltrating breast tumor T1 had been studied. There wasn't clinical and ultrasonographic evidence of axillary infiltration. Tumors had been injected on the day before surgery with a mixture of colloidal human albumin particles marked with 99m Technetium. In 108 out of 109 patients (99%) sentinel node had been identified using a gamma probe and biopsied during surgical intervention performed under local anesthesia. Sentinel node has been examined both with conventional histology and immunohistochemistry. In 26 cases the node was positive for metastases. Radical axillary dissection in this subgroup of patients showed that in 85% of them sentinel node was the only positive. We conclude that sentinel node biopsy can be a good alternative to traditional axillary dissection but there are still important questions about the best method of analysis and, before the technique become a routine procedure in breast cancer management, we should know the results of prospective clinical trials comparing survival of patients staged by sentinel node biopsy versus traditional axillary dissection.

Possible roles of extracellular matrix and cytoskeleton in leech body wall muscles.

Round circomyarian fibres of leeches are peculiar helical muscles. The fibres are characterized by a lack of junctions, being separated by a thick extracellular matrix, and by scarce end-plates. Even so, the fibres grouped in units show the same degree of contraction. Biochemical, immunocytochemical and ultrastructural studies were performed in order: (a) to demonstrate the presence in the extracellular matrix of fibronectin, collagen type IV and laminin and in the cytoskeleton of desmin and alpha-actinin; (b) to show the possible link of extracellular matrix with the scaffold of intermediate filaments; (c) to evaluate how the extracellular matrix can play a role in the transduction of a signal during contraction-relaxation-superelongation phases.

Discriminant power and information content of Ranson's prognostic signs in acute pancreatitis: a meta-analytic study.

OBJECTIVE: To determine a meta-analytical definition of the discriminant power of Ranson's signs in the prediction of acute pancreatitis severity and outcome, and of their information content, also compared with clinical judgment. DATA SOURCES: Two hundred eleven studies since 1974, reporting any predictive system for acute pancreatitis (MEDLINE by various Medical Subject Headings in MEDLARS, Current Contents, Medscape, Virtual Hospital, and other on-line medical services). STUDY SELECTION: One hundred ten studies reporting clinical use of Ranson's signs were retained. A quality index was calculated for each study. A selection was made according to inclusion criteria, separately for prediction of severity (19 studies; group S) and prognosis (10 studies; group P). Six other studies reporting clinical judgment results were also selected (group C). DATA EXTRACTION: Sensitivity and specificity values were extracted. Effect sizes were calculated and summarized by the inverse variance-weighted method. Categorical models were studied by analysis of variance. Publication bias was sought by correlation test and analysis of variance. Summary receiver operating characteristic curves were drawn, and the corresponding false-positive rate (FPR) and true-positive rate were calculated for each group. From the total true-positive rate and FPRs, the probabilities of illness for positive and negative results were calculated, for severe pancreatitis prevalence from 0 to 1. Last, the area below the curve and the ratio between this and that of the "perfect test" were calculated as a measurement of information content. DATA SYNTHESIS: Ranson's signs demonstrated poor discriminant power in both predictions: "d" values were 1.200 (95% confidence interval, 1.083-1.318) and 1.302 (95% confidence interval, 1.046-1.559), respectively. The lack of homogeneity in group S (Q = 58.737; p = .0000032) can be explained by the presence of three outliers. The summary curves showed, for low FPRs, a higher sensitivity of clinical judgment; Ranson's signs reached useful sensitivity only for high FPRs. No differences between groups in the area below the information content curves were found. CONCLUSIONS: Ranson's signs showed a poor predictive power. The information content did not differ from that of clinical judgment.

Total anorectal reconstruction by double graciloplasty: experience with delayed, selective use of implantable pulse generators.

This study reports our experience with total anorectal reconstruction (TAR), supported at a later phase, whenever necessary, by an implantable pulse generator. Thirteen patients underwent total anorectal reconstruction by double graciloplasty, diverting loop colostomy, and implantation of temporary electrodes. External-source, short-term, intermittent electrostimulation and biofeedback were used for neosphincter voluntary control training. After abdominal stoma closure, 6 months after initial surgery in disease-free patients, functional results were evaluated by a scoring system and anomanometry. A pulse generator was implanted whenever continence was judged unsatisfactory. After continuous electrostimulation training, neosphincter function was reassessed. Major graciloplasty complications (partial muscle necrosis and perineal colostomy necrosis) were treated successfully by surgery. One death of myocardial infarction occurred after discharge. Three patients refused further surgery. One patient did not undergo abdominal stoma closure because of early hepatic metastases. Functional evaluation after closure (eight patients) showed the following results: two "excellent" (no pulse generator implanted), three "good" (two stimulator implantations, with an "excellent" result), two "fair", and one "poor" (3 implantations, with a "good" result). In addition to improving clinical results (P=0.042), resting anal pressures were also increased significantly by active an implantable pulse generator (P=0.043). Although stimulators, whenever implanted, improved the neosphincter function, delayed, selective use of these in some cases rendered an implantable pulse generator either unnecessary from a functional viewpoint or redundant because of cancer recurrence or infectious complications. Drawbacks to the procedure were poor patient compliance to neosphincter training and to multiple surgical procedures, and excessive wasting of human resources during training for intermittent electrostimulation and biofeedback.

Histopathological changes after induced injury in leeches.

Cells involved in leech inflammatory responses have been characterized by morphological, histochemical, and immunohistochemical methods. Macrophage-like cells, NK-like cells, and granulocytes migrated shortly after injury by pricking with bacterial lipopolysaccharide. Inflammatory responses increased progressively and provoked cell migration to the body wall and then to wound surfaces. Macrophages, NK cells, and granulocytes display similar features and behavior traits in invertebrates and vertebrates.

Aerosol observations by lidar in the nocturnal boundary layer.

Aerosol observations by lidar in the nocturnal boundary layer (NBL) were performed in Potenza, Southern Italy, from 20 January to 20 February 1997. Measurements during nine winter nights were considered, covering a variety of boundary-layer conditions. The vertical profiles of the aerosol backscattering coefficient at 355 and 723.37 nm were determined through a Klett-modified iterative procedure, assuming the extinction-to-backscattering ratio within the NBL has a constant value. Aerosol average size characteristics were retrieved from almost simultaneous profiles of the aerosol backscattering coefficient at 355 and 723.37 nm, the measurements being consistent with an accumulation mode radius not exceeding 0.4 microm. Similar results in terms of aerosol sizes were obtained from measurements of the extinction-to-backscattering ratio profile at 355 nm performed on six nights during the measurement campaign. Backscattering profiles at 723.37 nm were also converted into profiles of aerosol liquid water content.

Double-gracilis anorectal neosphincter: technique of reconstruction after necrosis of the distal part of the muscles.

PURPOSE: The aim of the present study is to demonstrate further reconstruction of a double-gracilis anorectal neosphincter that had been destroyed because of a severe postoperative perineal infection, with necrosis of the distal part of the muscles. METHOD: Each residual gracilis muscle was split longitudinally into two branches, which surrounded the neorectum, one posteriorly and the other one anteriorly, so as to perform a perineorectal double sling. RESULT: Owing to a poor functional result, continence was achieved only by the support of an implantable pulse generator. CONCLUSION: This technique seemed to permit the optimum use of the contractile potential of the residual gracilis muscles, which did not show evidence of defunction-related or ischemia-related fibrosis.

[Method and application limitations of decision support systems in acute pancreatitis]. / Limiti metodologici e applicativi dei sistemi di supporto alle decisioni nella pancreatite acuta.

Several decision support systems (DSSs) for acute pancreatitis (AP) were analyzed with reference to development methods, procedure limits and operational performances. Almost all the DSSs have been addressed to the early definition of severity, which appears the only decisional point in the approach to the management of AP. None of the three groups of methods, multifactor, scoring and bayesian systems, provides an explicit evidence of effectiveness. The multifactor systems (Ranson and successive) show inadequacy of design and operational limits which involve poor reliability and conflicting indications from the different centers. The scoring systems (APACHE, SAPS) have been projected and developed for clinical situations quite different from the AP at the onset, and seem more properly to be applicable to the monitoring of its complications. The bayesian systems, although the models used until now present important methodological shortcomings, are those which furnished the best results but are lacking in clinical validation and present a form hardly accepted by the clinician. Despite the disappointing operative results and their limited use in the AP, the DSSs probably constitute one of the most effective tools to improve the management of the severe forms, on condition that the methodology of design enad trial is correctly adjusted.

Continent perineal colostomy by electrostimulated graciloplasty in abdominoperineal resection. A preliminary report.

Despite the tendency toward sphincter-saving surgical procedures, a small proportion of rectal cancers must still be treated by abdominoperineal resection (APR). The physical, psychological and social consequences of a permanent abdominal stoma are a challenge to perform a continent perineal colostomy. Most of the attempts originate from experiences with gracilis muscle transposition in the treatment of fecal incontinence, in particular Pickrell's operation. Functional results are however conditioned by the fact that the transposed muscle takes up a different function and its natural evolution, if not adequately stimulated, consists of atrophy and fibrosis. The most important series of graciloplasty in APR is reported by Cavina and coworkers (75 cases from 1985 to 1993), who at first obtained good functional results by external electromyostimulation (EMS) and biofeedback, then registered a further improvement using internal, continuous low-frequency EMS by implantable pulse generators (IPG). The surgical technique involves, after APR: bilateral dissection of the gracilis up to the proximal neurovascular pedicle and detachment of the distal tendon; mobilization of the muscles, through the subcutaneous tissue, into the perineum, where the colonic stump is drawn out; positioning the right gracilis behind the colonic stump, as a puborectalis sling, and the left gracilis around it, in a sort of "alpha" configuration; suturing the colonic stump to the perineal skin; optionally, temporary diverting loop colostomy. The operation is completed by the insertion of two electrodes near the nerve, for external or internal EMS (in the last case: implantation of IPG). The external EMS may be carried out by current cardiac temporary electrodes, drawn up through the skin of the iliac area. It is aimed at preserving the trophism and the contractility of the muscle and enabling the patient to learn a new function of continence (actually, it is a "pseudocontinence"), thanks to a program of intermittent stimulation and biofeedback. Electrodes and other devices are not expensive. The internal EMS requires specific electrodes, connected to an IPG, implanted in a subcutaneous abdominal pocket. The continuous stimulation gives rise to a tonic activity of the gracilis, resulting in higher resting anal pressure and "true" continence. The IPG is programmed under telemetry control, step by step until the most suitable EMS parameters are reached. A magnet allows the patient to turn the IPG "off" of "on", according to the necessity to void the bowel. A complete set of 1 IPG and 2 electrodes costs about $10,000. Cavina reports good continence in 71% of the cases treated by external EMS and 100% of the patients with IPG. Our first graciloplasty in APR was performed in April 1994. Since then we have carried out 6 operations. Because of its high cost, we decided that, at least at a first phase, the IPG should be implanted, from the 7th month on, only in disease-free patients, when functional results suggested a possible clinical improvement. Until today, 3 patients have had the abdominal stoma closed and can be evaluated from a functional viewpoint. We recorded 1 "excellent" and 2 "fair" results. In the two patients with a "fair" result we implanted a pulse generator about a month after the closure of the abdominal colostomy. A good manometric and clinical improvement was registered. The patient with "excellent" functional result had a recurrence one month after the closure of the stoma. Though limited, our experience is absolutely favourable as to graciloplasty, but an evaluation from us whether external or internal EMS is better, is too early at the moment. In absolute functional terms, the internal, continuous EMS is preferable, but problems of cost and oncologic prognosis restrict the use of IPG.

[Jejunal carcinoma: apropos 8 cases]. / Il carcinoma del digiuno: a proposito di 8 casi.

The tumors of the small bowel are uncommon. About one-third are jejunal, for the most part adenocarcinomata. From 1976 to 1994 we operated on 8 patients affected by jejunal adenocarcinoma, mean age 59 years (+/- 15.2), range 37-78, which are 0.33% of all the malignant epithelial neoplasms of the digestive tract, treated in the same period. In six cases the diagnosis was preoperative, by x-ray or instrumental investigations. In the other two patients the neoplasm was found intraoperatively. Only five operations were curative. In six cases the neoplasm invaded the serosa and, in three, also the mesenterium. A chemotherapy was carried out in the last five patients. One of these underwent right hepatectomy for single metastasis, 26 months after the primary operation. Until now we registered three deaths, one of which for causes unrelated to the cancer. After discussing epidemiology and diagnostics, the authors evaluate the therapeutical possibilities, mainly consisting of surgery, and dwell upon technical aspects and results.

[The prognostic evaluation of acute pancreatitis]. / Valutazione prognostica della pancreatite acuta.

Early identification of severity is one of the most important problems in acute pancreatitis, both for decision-making and classification. Predictive criteria show a wide range of accuracy: clinical examination (on admission: 76-85%); single laboratory data (PCR: 68-98%, C3-C4: 63-72%); multifactorial scoring systems (Ranson: 65-82%, Imrie: 78-95%); diagnostic peritoneal lavage (72-90%); CT features (52-81%). In 1982 we started a prospective evaluation of the prognostic performances of a bayesian statistical model for the prediction of severe vs mild pancreatis and death vs survival, which uses the outcome-related patterns of several variables, assuming their independence, analysed on a data of 44 patients. The performances have been calculated prospectively by comparing the expected vs actual results on 88 further patients (accuracy, sensitivity and specificity, respectively, in the prediction of severe pancreatitis: 92%, 92%, 93%; in the prediction of death: 95%, 97%, 87%). Moreover, the model can represent classes of risk by combining prediction of death + severe pancreatitis (DSP), survival + severe pancreatitis (SSP) and survival + mild pancreatitis (SMP) (accuracy, sensitivity and specificity, respectively, in the prediction of DSP: 97%, 83%, 100%; in the prediction of SSP: 95%, 87%, 97%; in the prediction of SMP: 95%, 97%, 90%). Our model enables clinicians dealing with other population to re-determine different variables or integrate them with new information, whenever available. It seems to be transferable and adaptable, even with a probable further increase of the performances, without compromising the objectivity of the predictive judgement and the homogeneity of the classes of risk.

[Gastric carcinoma in the elderly (clinical findings and results)]. / Il carcinoma gastrico nell'anziano (rilievi clinici e risultati).

On the basis of a series of 643 patients operated on for gastric cancer, the Authors seek to establish whether this disease presents clinical differences with advancing age of such a nature as to have a significant effect on therapeutic management. The series is divided into two groups, the first consisting of patients aged below 70 and the second of patients aged over 70. The following aspects were evaluated: sex, tumour site, oncological stage, type of surgery performed, operative mortality, postoperative survival, as assessed in overall terms and also differentiated in relation to curative or palliative surgery and oncological stage. Analysis of the data confirms that, apart from certain particular aspects, carcinoma of the stomach in the elderly benefits from the same sort of indications and techniques as those proposed for younger patients, with comparable postoperative survival rates, but with a higher operative mortality. To achieve better operative results, what is needed, in addition to correction of metabolic and functional abnormalities, is thorough assessment of risk factors. In patients with tumours at advanced stages, usually characterized by very poor postoperative results, the presence of major risk factors may raise serious doubts as to the actual advisability of the surgical indication itself.