Cyclophilin D counteracts P53-mediated growth arrest and promotes Ras tumorigenesis.

Mitochondrial alterations induced by oncogenes are known to be crucial for tumorigenesis. Ras oncogene leads to proliferative signals through a Raf-1/MEK/ERK kinase cascade, whose components have been found to be also associated with mitochondria. The mitochondrial pepdidyl-prolyl isomerase cyclophilin D (CypD) is an important regulator of the mitochondrial permeability transition and a key player in mitochondria physiology; however, its role in cancer is still unclear. Using cellular and in vivo mouse models, we demonstrated that CypD protein upregulation induced by oncogenic Ras through the Raf-1/MEK/ERK pathway has a deterministic role in tumor progression. In fact, targeting CypD gene expression clearly affected RasV12-induced transformation, as showed by in vitro data on murine NIH3T3 and human MCF10A mammary epithelial cells. In addition, studies in xenograft and K-Ras lung cancer mouse models demonstrated that genetic deletion or pharmacological suppression of CypD efficiently prevented Ras-dependent tumor formation. Furthermore, Erbb2-mediated breast tumorigenesis was similarly prevented by targeting CypD. From a mechanistic point of view, CypD expression was associated with a reduced induction of p21(WAF1/CIP1) and p53 functions, unraveling an antagonistic function of CypD on p21-p53-mediated growth suppression. CypD activity is p53 dependent. Interestingly, a physical association between p53 and CypD was detected in mitochondria of MCF10A cells; furthermore, both in vitro and in vivo studies proved that CypD inhibitor-based treatment was able to efficiently impair this interaction, leading to a tumor formation reduction. All together, these findings indicate that the countering effect of CypD on the p53-p21 pathway participates in oncogene-dependent transformation.

The nature and frequency of blood contacts among home healthcare workers.

OBJECTIVE: To estimate the frequency of, and assess risk factors for, percutaneous, mucous membrane, and cutaneous blood contacts sustained by healthcare workers (HCWs) during the delivery of infusion therapy and the performance of procedures involving sharp instruments in the home setting. DESIGN: Prospective surveillance of percutaneous, mucous membrane, and cutaneous blood contacts. SETTING: Eleven home healthcare agencies in the United States and Canada from August 1996 through June 1997. PARTICIPANTS: HCWs who provided home infusion therapy or performed procedures using hollow-bore needles and other sharp instruments in the home setting. METHODS: Each participating worker recorded information about the procedures performed and blood contacts experienced during each of his or her home visits for a 2- to 4-week period using standard questionnaires. HCWs also completed questionnaires regarding job duties, reporting of previous occupational blood contacts, and their use of protective barriers in the home setting. RESULTS: Participating HCWs provided information about 33,606 home visits. A total of 19,164 procedures were performed during 14,744 procedure visits. Fifty-three blood contacts occurred during these visits, for a blood-contact rate of 2.8 blood contacts per 1,000 procedures and 0.6 percutaneous injuries per 1,000 procedures with needles or lancets. Gloves were worn for 52%, masks for 5%, gowns for 3%, and protective glasses or goggles for 2% of all procedure visits. HCWs used barriers for 53% of visits during which at least 1 procedure was performed and for 27% of other visits. CONCLUSIONS: HCWs involved in home health care are at risk for blood contact. Infection control barrier use was low in our study. The majority of skin contacts could have been prevented by glove use.

Risk factors for acquisition of vancomycin-resistant enterococci among patients on a renal ward during a community hospital outbreak.

BACKGROUND: During an outbreak of vancomycin-resistant enterococcal (VRE) infection and colonization at a community hospital in Indianapolis, Indiana, we performed a case-control study of patients on the hospital's renal unit to determine risk factors for acquisition of VRE among this potentially high-risk patient population. METHODS: Twenty-four renal patients with VRE colonization/infection (ie, case-patients) were compared by univariate and multivariate analyses with 29 renal patients with nosocomially acquired vancomycin-susceptible enterococcal infection and colonization (ie, controls). RESULTS: Age and length of hospitalization were similar between the VRE case-patients and the vancomycin-susceptible enterococcal control-patients, but case-patients had higher Acute Physiology and Chronic Health Evaluation II scores and received significantly greater numbers of antimicrobials and significantly more days of antimicrobials during the 60 days preceding the first positive enterococcal culture. In an assessment of the appropriateness of vancomycin use, one third of vancomycin orders were found to be inappropriate in both patient groups. CONCLUSIONS: Our data show that among renal patients, those who are severely ill and receive multiple and prolonged courses of antimicrobials are at greatest risk for acquiring VRE infection or colonization. The Centers for Disease Control and Prevention recommends that hospitals develop a comprehensive plan to prevent and control infection and colonization of patients with VRE. This plan should include prompt identification of affected patients, initiation of isolation precautions to prevent patient-to-patient transmission of VRE, and prudent use of antimicrobials, including vancomycin.

Assessing delirium in cancer patients: the Italian versions of the Delirium Rating Scale and the Memorial Delirium Assessment Scale.

To validate the Italian versions of the Delirium Rating Scale (DRS) and the Memorial Delirium Assessment Scale (MDAS), 105 cancer patients consecutively referred for neurological or psychiatric consultation for mental status change were evaluated using the Confusion Assessment Method (CAM), the DRS, the MDAS, and the Mini-Mental State Examination (MMSE). According to the CAM criteria and clinical examination, 66 patients were delirious, and 39 received diagnoses other than delirium. The DRS and the MDAS scores significantly distinguished delirious from non-delirious patients. The MDAS and the DRS were mutually correlated. When using the proposed cut-off scores for the two scales, the MDAS had higher specificity (94%) but lower sensitivity (68%) than the DRS (sensitivity = 95%, specificity = 61% for DRS cut-off 10; sensitivity = 80%, specificity = 76%, DRS cut-off 12). The MMSE showed high sensitivity (96%) and very low specificity (38%). Exploratory factor analysis of the DRS and the MDAS suggested a three-factor and two-factor structure, respectively. Both instruments in their Italian version proved to be useful for the assessment of delirium among cancer patients. Further research is needed to examine the use of the DRS and the MDAS in other clinical contexts.

The role of membrane patch size and flow in regulating a proteolytic feedback threshold on a membrane: possible application in blood coagulation.

Positive feedback controls in proteolytic systems are characterized by thresholds which are regulated by the concentration of the initial stimulus and the kinetic parameters for enzyme generation and inhibition. Significant complexity is added when a positive feedback is localized on a membrane in contact with a flowing medium, such as seen in the early steps of blood coagulation. A partial differential equation model of an archetypal feedback loop is examined in which a proteolytic enzyme catalyzes its own formation from a zymogen on a membrane in contact with a flowing medium. As predicted from prior solution-phase and membrane-phase analyses, the threshold conditions for activation of the system are regulated by the kinetics of enzyme generation and inhibition and by the density of reactant-binding sites on the membrane; but the present analysis also establishes how the feedback threshold is controlled by the flow rate of the adjacent medium and the physical size of the membrane patch on which the feedback loop is localized. For given systems of particular kinetic properties, lower flow rates or larger active patches of membrane can result in the activation threshold being exceeded, whereas higher flow rates or smaller membrane patches can prevent initiation. In addition to numerical simulation, a simplified non-flowing model is analyzed to formulate an approximate mathematical statement of the dependence of the minimum activatable patch size on the kinetic and other parameters.

[Single-stage laparoscopic surgery of cholelithiasis and choledocholithiasis in 268 unselected consecutive patients]. / Trattamento laparoscopico in tempo unico della litiasi colecisto-coledocica in 268 pazienti consecutivi non selezionati.

AIMS: The introduction of laparoscopic cholecystectomy (LC) has modified the treatment of gallstones and common bile duct (CBD) stones. Aim of this prospective study was to evaluate the results of single stage laparoscopic management of gallstones and CBD stones. PATIENT AND METHODS: From January 1991 to October 1999, CBD stones were present at intraoperative cholangiography in 268 patients (pts) (169 females, 99 males, mean age 55.6 years, range 12-94 years) out of 2693 undergoing LC (10%) for gallstones. CBD stones were unsuspected in 123 (45.9%) and suspected in 145 (54.1%). RESULTS: CBD exploration was successful in 264 cases (98.5%) (transcystic 164, choledochotomy 100). Four pts were converted to open surgery (1.5%). Retained stones in 15 patients (5.7%), were treated by ERCP/ES (6 pts) and by percutaneous endoscopic/fluoroscopic stone removal (6 pts). Spontaneous stones passage occurred in 2 pts, one patient is waiting for treatment. Major morbidities were hemoperitoneum (4 cases) and cystic duct bile leakage (3 cases). One high risk patient died postoperatively. Recurrent stones were observed in 5 pts (1.9%), at 1, 4, 8, 18, 26 months respectively after T-tube removal, and were treated by ERCP/ES in 4 cases. Spontaneous stone passage occurred in 1 case. CONCLUSIONS: LC and CBD exploration has shown to be safe and feasible with low morbidity and mortality. The rationale of this approach is to solve two problems during the same procedure, limiting the role of endoscopic sphincterotomy to the treatment of residual ductal stones.

Mathematical analysis of activation thresholds in enzyme-catalyzed positive feedbacks: application to the feedbacks of blood coagulation.

A hierarchy of enzyme-catalyzed positive feedback loops is examined by mathematical and numerical analysis. Four systems are described, from the simplest, in which an enzyme catalyzes its own formation from an inactive precursor, to the most complex, in which two sequential feedback loops act in a cascade. In the latter we also examine the function of a long-range feedback, in which the final enzyme produced in the second loop activates the initial step in the first loop. When the enzymes generated are subject to inhibition or inactivation, all four systems exhibit threshold properties akin to excitable systems like neuron firing. For those that are amenable to mathematical analysis, expressions are derived that relate the excitation threshold to the kinetics of enzyme generation and inhibition and the initial conditions. For the most complex system, it was expedient to employ numerical simulation to demonstrate threshold behavior, and in this case long-range feedback was seen to have two distinct effects. At sufficiently high catalytic rates, this feedback is capable of exciting an otherwise subthreshold system. At lower catalytic rates, where the long-range feedback does not significantly affect the threshold, it nonetheless has a major effect in potentiating the response above the threshold. In particular, oscillatory behavior observed in simulations of sequential feedback loops is abolished when a long-range feedback is present.

Mathematical analysis of a proteolytic positive-feedback loop: dependence of lag time and enzyme yields on the initial conditions and kinetic parameters.

A model of a proteolytic positive-feedback loop, similar in general terms to feedback loops that occur in blood coagulation and other systems, has been examined by both explicit and numerical analysis. In this loop, modeled as a closed system, each enzyme (E1, E2) catalyzes the formation of the other from its respective zymogen (Z1, Z2), and both enzymes are subject to irreversible inhibition. The system shows three major characteristics. (1) No significant Z1 or Z2 activation occurs unless the combination of initial conditions and kinetic parameters is above a threshold level. This threshold occurs when the product of the enzyme generation rates equals the product of their inhibition rates. When the formation-rate product is less than the inhibition-rate product, there is no response: E1 and E2 generation is minimal and the lag time is effectively infinite. Conversely, when the generation-rate product exceeds the inhibition-rate product, explosive formation of both E1 and E2 is seen. For responses exceeding the threshold, the following obtain. (2) The lag time in E1 and E2 generation is a highly nonlinear function of the zymogen concentrations and the enzyme generation and inhibition rates. In contrast, there is a simple logarithmic relationship between the lag time and the initial trace concentration of the enzyme that is responsible for initiating the system; in this model, E1. (3) The extent of Z1 and Z2 activation is similarly a nonlinear function of the conditions and parameters but is independent of the initiating trace level of E1.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of the exploratory probe on demineralized enamel]. / O efeito da sonda exploradora no esmalte desmineralizado.

This study aims to demonstrate the effect of dental explorer on demineralized enamel. Bovine teeth were divided perpedinculary towards their long axis. Each section were provided with 2 grooves, parallels to the teeth's axis. These sections were exposed to an acid solution for 7 days. After this period just one of the grooves of each section was probed ahd then, the demineralization was continued for one more wee. Then we could compare the lesions depths of demineralization of the probed grooves and the non probed grooves. The probed grooves presented an increased lost of enamel structure, more than the non probed grooves. It was concluded that the careless use of dental explorer on diagnosis of fissures caries cause mechanical damage to enamel already softened as a result of a carious attack.

[Increased resistance to demineralization on enamel cavity walls by application of fluoride solution]. / Aumento da resisténcia á desmineralização de paredes cavitárias de esmalte pela aplicação de solução fluoretada.

Dental enamel cavity walls of bovine extracted incisors were submitted to different treatments before to be "restored" with amalgam. The Group A non received treatment; the Group B received only a conventional cavity varnish and the Group C received a solution of sodium fluoride (2%) + conventional cavity varnish (2 applications). After 7 days of immersion in gel acid, the ground sections were studied in polarized microscope. The Group C that received sodium fluoride + conventional cavity varnish presented more resistance to demineralization. The Group B that received only cavity varnish presented a reduction in resistance to demineralization, and the Group A that non received treatment presented minor resistance to demineralization. Therefore, is emphasized the importance of application of sodium fluoride in cavity walls before lining with conventional cavity varnish and restoring with amalgam to obtain more resistance to demineralization.

[Definitive diagnosis of proximal caries by temporary separation of posterior teeth]. / Diagnóstico definitivo de cáries proximais do esmalte pelo uso da separação temporária dos dentes posteriores.

The authors present a review of diagnosis methods of approximal carious lesions and emphasises the necessity, in cases of incipient carious lesions, of using dental temporary separation to provide an inequivocal diagnosis. The temporary tooth separation offers preservation of dental structure and permits application of preventive and restorative procedures and monitoring incipient carious lesions. Selected methods of temporary dental separation are presented.

Automated screening for quality of care in the hospital--a feasibility study.

A feasibility study for computer-based quality screening was carried on 497 clinical cases. Rule-directed audit criteria were used. Discharge summaries were analyzed in an effort to detect possible quality problems. The charts of the same cases were also screened by nurses, and the suspected cases of both process es were further reviewed by physicians. The computer-based text analysis compared favorably with the screening by nurses, and showed a rather low false negative rate. The objectives of substantiating the discharge summary as a valid source document for generic quality screening was demonstrated. In addition the economy and feasibility of computer based text analysis and interpretation was proven. Finally the applicability of algorithmic rules in detecting clinical quality indicators showed great promise and presents an area of further research. Thus the feasibility study was highly successful. The potential of computer-based care quality assessment is discussed.

Scleroglucan sustained release oral preparations. Part II. Effects of additives.

Swelling and diffusion experiments, performed in vitro with tablets prepared with scleroglucan and several hydrophilic and hydrophobic additives, indicate that it is possible to modulate drug delivery from the matrix by appropriate choice of the nature and amount of the additive. The additives in the formulations may affect the mechanisms (zero order, diffusion, erosion) involved in the release of drugs from the dosage forms.

Risk and management of blood-borne infections in health care workers.

Exposure to blood-borne pathogens poses a serious risk to health care workers (HCWs). We review the risk and management of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections in HCWs and also discuss current methods for preventing exposures and recommendations for postexposure prophylaxis. In the health care setting, blood-borne pathogen transmission occurs predominantly by percutaneous or mucosal exposure of workers to the blood or body fluids of infected patients. Prospective studies of HCWs have estimated that the average risk for HIV transmission after a percutaneous exposure is approximately 0.3%, the risk of HBV transmission is 6 to 30%, and the risk of HCV transmission is approximately 1.8%. To minimize the risk of blood-borne pathogen transmission from HCWs to patients, all HCWs should adhere to standard precautions, including the appropriate use of hand washing, protective barriers, and care in the use and disposal of needles and other sharp instruments. Employers should have in place a system that includes written protocols for prompt reporting, evaluation, counseling, treatment, and follow-up of occupational exposures that may place a worker at risk of blood-borne pathogen infection. A sustained commitment to the occupational health of all HCWs will ensure maximum protection for HCWs and patients and the availability of optimal medical care for all who need it.

[Marginal leakage of composite resin and glass ionomer]. / Infiltração marginal da resina composta e ionómero de vidro.

A study was developed to compare the marginal leakage by basic fuchsin dye, around cervical restorations after applying composite resin + dentin adhesive and composite resin + glass ionomer cement. Cervical cavities were prepared on the lingual and vestibular surfaces in 19 freshly extracted human teeth. The lingual cavities were restored with composite resin + dentin adhesive, and the vestibular cavities were restored with composite resin + glass ionomer cement ("Sandwich's" technique). After placement of each restoration, these teeth were thermocycled, immersed in dye solution. After removal from the dye, the teeth were sectioned through the restorations, along the long axis of the crown, and analyzed the leakage's degree. The composite resin + glass ionomer cement restorations, showed marginal leakage between the restorative material and the cervical margin but, generally since the middle of this wall.

Assessment of hospitalised cancer patients' needs by the Needs Evaluation Questionnaire.

BACKGROUND: Cancer disease modifies the order and the nature of needs connected with the state of health. The aim of this study was to evaluate the informative, psychological, social and practical needs of hospitalised cancer patients by means of the Needs Evaluation Questionnaire (NEQ), an instrument designed concisely for the convenience of patients and medical staff. PATIENTS AND METHODS: Different samples of consecutive hospitalised cancer patients were involved in the various phases of designing the instrument: 30 patients for items identification, 101 patients for completeness and acceptability evaluation, 423 patients for construct validity and prevalence of needs; content and reliability analysis were performed on 2 subsamples of, respectively, 60 and 88 of the patients from the last sample. RESULTS: The validation analysis showed rather good reliability, structure validity and internal consistency of the questionnaire. The prevalence analysis showed that the most common needs were: 'more information about my future conditions' (74%); 'more information about my diagnosis' (56%); 'more information about the exams I am undergoing' (52%); 'more explanations on treatments' (51%); 'to have a better dialogue with clinicians' (57%); 'better services from the hospital' (bathrooms, meals, cleaning) (56%). CONCLUSIONS: The NEQ, self-completed by patients, has proven to be a useful clinical tool for obtaining a systematic and undistorted overview of the principal needs with respect to the state of health of patients. This instrument, which can also be administered by persons not belonging to the health care system such as volunteers, and inserted into the patients' hospital charts, could be used by the medical staff to identify the real needs of patients at an early stage.