Structure of the uracil complex of Vaccinia virus uracil DNA glycosylase

Poxvirus uracil DNA glycosylases are the most diverse members of the family I uracil DNA glycosylases (UNGs). The crystal structure of the uracil complex of Vaccinia virus uracil DNA glycosylase (D4) was determined at 2.03 Å resolution. One uracil molecule was located in the active-site pocket in each of the 12 noncrystallographic symmetry-related D4 subunits. Although the UNGs of the poxviruses (including D4) feature significant differences in the characteristic motifs designated for uracil recognition and in the base-excision mechanism, the architecture of the active-site pocket in D4 is very similar to that in UNGs of other organisms. Overall, the interactions of the bound uracil with the active-site residues are also similar to the interactions previously observed in the structures of human and Escherichia coli UNG.

How often do patients return to the operating room after colorectal resections?

AIM

We sought to identify the rate of re-operation after an index colorectal surgical procedure and potential contributing risk factors.

METHOD

This is a retrospective cohort study from the American College of Surgeons National Surgical Quality Improvement Program. We identified all patients who either returned or did not return to the operating room after any colorectal resection from January 2005 to December 2008.

RESULTS

From a total cohort of 635, 265 patients included in the National Surgical Quality Improvement Program over the 4-year study period, we identified 54, 237 patients who underwent colorectal operations. A return to the operating room was coded in 5.4 ± 0.1% of non colorectal resection patients and 7.6 ± 0.2% of colorectal resection patients (P < 0.001). The multivariate model identified patients with postoperative diagnostic codes for abdominal cavity hernia or colostomy complication as having the highest odds of return to the operating room within 30 days. Patients returning to the operating room had longer length of stay and higher overall mortality compared with those patients who did not return to the operating room.

CONCLUSION

Return to the operating room is a relatively common occurrence after colorectal resections, with an associated high rate of mortality. Given the association between return to the operating room and adverse patient outcomes, emphasis should be placed on determining strategies to reduce the need for return to the operating room.

Do admissions and discharges to long-term care facilities influence hospital burden of Clostridium difficile infection?

BACKGROUND

Substantial geographical clustering of Clostridium difficile infection (CDI) outbreaks in hospitals in the USA have previously been demonstrated.

AIM

To test the hypothesis that hospital burden of CDI is associated with admission from and discharge to long-term care facilities (LTCFs).

METHODS

Hospital discharge data from 19 states in the USA were used to identify all patients discharged with a diagnosis of CDI from 1 January 2002 to 31 December 2004. For every hospital, the proportion of discharges with a diagnosis of CDI was calculated, and those above the 90th percentile were classified as 'high CDI' hospitals. We tested the association between this measure of hospital burden of CDI and the rates of admission from and discharges to LTCFs. We adjusted for other hospital level characteristics, case-complexity and local population characteristics.

FINDINGS

We identified 38,372,951 discharges during the three-year study period. Of all discharges, 274,311 (0.71%) had a primary or secondary diagnosis of CDI. Hospitals had a mean CDI burden of 7.8 cases per 1000 discharges. High CDI hospitals (N = 610; 10.0%) had a mean CDI burden of 34.8 cases per 1000 discharges. Compared to other hospitals, high CDI hospitals were more likely to have a high proportion of admissions from or discharges to LTCFs. This association persisted after adjustments for other hospital characteristics, case-complexity, and area population characteristics.

CONCLUSION

A high rate of admission from or discharge to LTCFs is associated with an increased hospital burden of CDI.

In vitro activity of tigecycline against multidrug-resistant Acinetobacter baumannii clinical isolates

This survey was conducted to evaluate the in vitro activity of tigecycline against 50 isolates of multidrug-resistant (MDR) Acinetobacter baumannii. Isolates of A. baumannii were resistant to ciprofloxacin, chloramphenicol, imipenem, levofloxacin, piperacillin and piperacillin-tazobactam, but were always susceptible to colistin. MICs of tigecycline were determined by E-test in Mueller-Hinton agar. The results of the study showed that 50% of the A. baumannii strains were susceptible to tigecycline.

[In vitro activity of voriconazole and other antifungal agents against clinical isolates of 138 Candida spp]

Voriconazole is used for treating invasive Aspergillosis, Fusarium and Scedosporium infections as well as resistant candidiasis. It is referred to as a second generation triazole. The purpose of this study was to evaluate the concordance of the results of antifungal voriconazole susceptibility tests for yeast isolates, comparing the Sensititre YeastOne method, Atb Fungus 3 and Etest. In all, 138 yeast isolates (42 C. tropicalis, 36 C. glabrata, 14 C. albicans, 8 C. famata, 6 C. parapsilosis, 4 C. dubliniensis, 3 C. krusei, 3 C. lusitaniae, 2 C. zeylanoides, 20 Candida spp.) were tested for susceptibility to amphotericin B, flucytosine, fluconazole , itraconazole and voriconazole with Atb Fungus 3 method. The concordance between the Sensititre YeastOne method, Atm Fungus 3 and Etest for voriconazole was high (90%).

[Some behavioral characteristics of physicians desired by ambulatory patients. A pilot survey]

AIMS

We must pay attention to character formation of Medical Doctors because it could build a good or bad relationship with colleagues and patients: it is not a merely "humanistic" goal but a necessary component of professional excellence. The first endpoint of this study is to identify how to improve the quality of the outpatient visit.

MATERIALS AND METHODS

We tested a user-friendly questionnaire, distributed to 100 patients.

RESULTS AND CONCLUSIONS

The most important behavioral characteristics desired by patients from physicians are: 1. to have the physician's attention without feeling hurried (such as without the physician answering a phone call during the office visit); 2. to have continuity of care even in the ambulatory setting; 3. to find a relationship of empathy, participation and sharing; 4. to have a peaceful relationship of collaboration with the nurses and other health care personnel; 5. to find the physician appropriately groomed and dressed; 6. to receive the full diagnosis with clarity and at the most appropriate moment of communication.

Predictors of Clostridium difficile colitis infections in hospitals

Hospital-level predictors of high rates of 'Clostridium difficile-associated disease' (CDAD) were evaluated in over 2300 hospitals across California, Arizona, and Minnesota. American Hospital Association data were used to determine hospital characteristics associated with high rates of CDAD. Significant correlations were found between hospital rates of CDAD, common infections and other identified pathogens. Hospitals in urban areas had higher average rates of CDAD; yet, irrespective of geographic location, hospital rates of CDAD were associated with other infections. In addition, hospitals with 'high CDAD' rates had slower turnover of beds and were more likely to offer transplant services. These results reveal large differences in rates of CDAD across regions. Hospitals with high rates of CDAD have high rates of other common infections, suggesting a need for broad infection control policies.

Blastomyces dermatitidis of the perianal skin: report of a case

Isolated fungal infections of the perianal skin are rare and their diagnosis is frequently overlooked. We report a case of a 78-year-old male patient who presented with a friable, violaceous, papulopustular lesion, with heaped-up edges along the anal verge. Biopsy revealed unicellular yeast consistent with blastomycosis. The patient was treated with itraconazole with resolution of this lesion. An extensive MEDLINE literature review from 1958 to the present indicates that this is an uncommon manifestation of cutaneous blastomycosis. A summary of the medical literature is presented with a review of the characteristics, diagnosis, and management of blastomycosis.

Causes of portal venous thrombosis in cirrhotic patients: the role of genetic and acquired factors

OBJECTIVE AND METHODS

We compared frequencies of three common prothrombotic mutations (factor V Leiden, the G20210A mutation of the prothrombin gene, and homozygosity for C677T methylenetetrahydrofolate reductase) in 219 cirrhotic patients, 43 with and 176 without portal vein thrombosis (PVT). The following variables were related to PVT: prothrombin levels, platelet count, Child-Pugh classification, previous abdominal surgery, number of decompensation events, size of varices, red markers on varices, and sclerotherapy. All patients were followed up for a mean period of 18 months (range 10-30).

RESULTS

Prothrombotic mutations were detected in 64 of the 219 cirrhotic patients (29.2%), at equal frequency in patients with or without PVT. At univariate analysis, PVT was associated with Child-Pugh classes B and C, signs of liver decompensation, large varices with red markings, sclerotherapy, and abdominal surgery. At multivariate analysis, PVT was associated with sclerotherapy [odds ratio (OR) 4.9, 95% confidence interval (CI) 2.2-11] and previous surgery (OR 2.8, 95% CI 1.2-6.3). The combination of the two acquired factors increased the risk of PVT, whereas the combination of local with genetic defects did not. Only a single patient with genetic thrombophilia and without PVT at inclusion developed the complication during follow-up, concomitantly with the development of hepatocellular carcinoma.

CONCLUSION

In cirrhotic patients prothrombotic mutations by themselves are not causative of PVT. Sclerotherapy and previous abdominal surgery favour the development of two-thirds of cases of PVT; in the remaining cases the pathogenesis remains elusive.

13C-breath tests in hepatology (cytosolic liver function)

13C-phenylalanine (PheBT) and 13C-galactose breath tests (GBT) explore non invasively the hepatic functional mass by measuring two enzymatic activities localized into the cytosol of liver cells: the phenylalanine hydroxylase (which converts phenylalanine into tyrosine) and the galactose kinase (which catalyzes the ATP-dependent phosphorylation of galactose to galactose 1-phosphate). Both BTs are safe and accurate in predicting the severity of liver cirrhosis showing a good correlation with the Child-Pugh score. PheBT is also used in predicting postoperative complications and monitoring liver regeneration in patients undergoing partial hepatectomy. GBT has been also used to assess liver fibrosis in patients with chronic hepatitis C. PheBT and GBT could be used in the diagnosis of two inborn errors of metabolism, phenylketonuria and galactosemia, respectively. Both BTs are not affected by enzymatic induction due to drugs which may interfere with the results of the classic "microsomial" BTs (such as the aminopyrine or caffeine BTs).

Independent Predictors of Morbidity and Mortality in Blunt Colon Trauma

We sought to determine the impact of (1) grade of the colon injury, (2) the formation of an ostomy, and (3) associated injuries on outcomes such as morbidity and mortality after blunt colon injuries. We retrospectively reviewed 16,814 cases of blunt abdominal trauma. Patients with colonic injuries were selected and charts reviewed for demographic, clinical, and outcomes data. Injuries were grouped by the Colon Injury Scale (grades I–V). Independent risk factors of morbidity included spine and lung injuries, as well as increased age. A higher grade of colon injury trended toward a significant association with intra-abdominal complications. Independent risk factors of mortality included liver, heart, and lung injuries, as well as intracerebral blood and female gender. The grade of colon injury, the formation of an ostomy, and management of the colon trauma did not independently predict increased intra-abdominal complications, morbidity, or mortality. These results indicate that patients afflicted with blunt colon trauma experience a high rate of morbidity and mortality from associated injuries and or increased age. Treatment regimens directed at these factors will be most helpful in reducing the high morbidity and mortality after blunt colon trauma. Factors such as ostomy formation and management strategy are not associated with increased morbidity or mortality after blunt colon trauma.

Independent predictors of morbidity and mortality in blunt colon trauma

We sought to determine the impact of (1) grade of the colon injury, (2) the formation of an ostomy, and (3) associated injuries on outcomes such as morbidity and mortality after blunt colon injuries. We retrospectively reviewed 16,814 cases of blunt abdominal trauma. Patients with colonic injuries were selected and charts reviewed for demographic, clinical, and outcomes data. Injuries were grouped by the Colon Injury Scale (grades I-V). Independent risk factors of morbidity included spine and lung injuries, as well as increased age. A higher grade of colon injury trended toward a significant association with intra-abdominal complications. Independent risk factors of mortality included liver, heart, and lung injuries, as well as intracerebral blood and female gender. The grade of colon injury, the formation of an ostomy, and management of the colon trauma did not independently predict increased intra-abdominal complications, morbidity, or mortality. These results indicate that patients afflicted with blunt colon trauma experience a high rate of morbidity and mortality from associated injuries and or increased age. Treatment regimens directed at these factors will be most helpful in reducing the high morbidity and mortality after blunt colon trauma. Factors such as ostomy formation and management strategy are not associated with increased morbidity or mortality after blunt colon trauma.

Appropriateness of urea breath test: a prospective observational study based on Maastricht 2000 guidelines

BACKGROUND

The urea breath test is routinely used for diagnosing or confirming the eradication of Helicobacter pylori.

AIM

To evaluate the appropriateness of urea breath test referrals.

METHODS

The age, sex, symptoms, endoscopic findings, use of non-steroidal anti-inflammatory drugs, family history of gastric cancer or H. pylori infection and concomitant diseases of patients referred for urea breath testing in a 1-year period were recorded. The appropriateness of urea breath test referrals was judged according to Maastricht guidelines.

RESULTS

One thousand, three hundred and twenty subjects (47 +/- 16 years) were referred in 2001: 578 (43.8%) for the diagnosis and 742 (56.2%) for confirmation of the eradication of H. pylori. The urea breath test was considered to be appropriate in 836 (63.3%) patients, inappropriate in 192 (14.5%) and appropriate but avoidable in 292 (22.1%). The appropriateness ratios of urea breath test referrals were 4.6 and 9.0 (P < 0.0001) for general practitioners and gastroenterologists, respectively. Of the patients (n=230) with un investigated dyspepsia, who underwent urea breath testing according to a 'test and treat' strategy, 98 (42.6%) presented at least one risk factor for organic disease.

CONCLUSIONS

In Italy, nearly 36% of urea breath test referrals are inappropriate or could be avoided if all dyspeptic patients with risk factors were referred for endoscopy or all dyspeptic patients undergoing endoscopy were tested for H. pylori infection with biopsy methods. Both general practitioners and, to a lesser extent, gastroenterologists require educational programmes to deal effectively with H. pylori.

Activator protein 1 activation following hypoosmotic stress in HepG2 cells is actin cytoskeleton dependent

BACKGROUND

Following hypoosmotic stress-induced cell volume change, the actin cytoskeleton reorganizes itself. The role of this reorganization in the activation of the phosphatidylinositol 3-OH-kinase/protein kinase B/activator protein 1 (PI-3-K/PKB/AP-1) proliferative signaling cascade is unknown. Focal adhesion kinase (FAK) participates in the cytoskeleton-based activation of PI-3-K. We hypothesized that hypoosmotic stress-induced activation of PKB and AP-1 in HepG2 cells is dependent on an intact actin cytoskeleton and subsequent FAK phosphorylation.

METHODS

HepG2 cells were incubated for 1 h with or without 20 microM cytochalasin D, an actin disrupter, and were then exposed for up to 30 min to hypoosmotic medium (200 mOsm/L) to induce swelling. Tumor necrosis factor alpha (1.4 nM) and medium alone served as positive and negative controls, respectively. Western blots measured cytoplasmic phosphorylated or total FAK and PKB. EMSAs measured nuclear AP-1. All experiments were performed in triplicate.

RESULTS

Exposure to hypoosmotic stress resulted in activation of the following signaling messengers in a sequential fashion: (1) phosphorylation of FAK occurred by 2 min, (2) phosphorylation of PKB occurred by 10 min, (3) nuclear translocation of AP-1 occurred by 30 min. All three signaling events were abolished when these cells were pretreated with cytochalasin D.

CONCLUSION

Actin reorganization following hypoosmotic stress is essential for the FAK-mediated activation of the PI-3-K/PKB/AP-1 proliferative cascade. These data delineate a possible mechanism by which the cell swelling-induced cytoskeletal changes can initiate proliferative signal transduction in human liver cancer.

Alterations in intrahepatic hemodynamics of the harvested porcine liver

Hemodynamic properties of a donor liver, during initial reperfusion, are associated with the degree of graft preservation injury and have been proposed to correlate with subsequent markers of liver function. In the present study, hepatic hemodynamics, that is, portal venous pressure, hepatic vascular resistance, and compliance (vascular distensibility), were characterized (1) in situ before porcine livers were manipulated, (2) after these same livers were isolated and perfused within a bypass circuit, and (3) on reperfusion after 2 hours of cold ischemia. Hepatic vascular resistance was determined in each of these three states from the portal vein pressure response to differing hepatic blood flows. In addition, the response of the same livers to norepinephrine and nitroprusside was evaluated in each condition. In the in situ and isolated perfused liver, portal venous pressure increased only modestly despite doubling of hepatic flows. After cold ischemia, the pressure response to higher flows was significantly greater and much less of a reduction in hepatic vascular resistance was noted than in studies prior to cold ischemia. Unlike livers prior to cold ischemia, the pressure response to norepinephrine was attenuated following cold ischemia. The response to nitroprusside, however, remained intact reducing the portal pressure to that of in situ livers. Therefore the portal hypertension that follows cold ischemia appears to be largely provoked by the preservation injury and not by surgical manipulation or the bypass circuit. This increment in portal pressure is responsive to a nitric oxide donor.

Hypoosmotic stress stimulates growth in HepG2 cells via protein kinase B-dependent activation of activator protein-1

Although hypoosmotic stress-induced cell swelling activates phosphatidylinositol-3-kinase, its impact on the downstream signal protein kinase B and cell growth is unknown. Activator protein-1 is in part phosphatidylinositol-3-kinase dependent, and is important in proliferation. We hypothesized that cell swelling modulates proliferation in HepG2 cells via the protein kinase B-dependent activation of activator protein-1. HepG2 cells pretreated with or without LY294002 were exposed for up to 30 minutes to hypoosmotic medium (160 mOsm/L). Tumor necrosis factor-alpha (1.4 nmol/L) or normoosmolar medium (270 mOsm/L) served as positive and negative controls, respectively. Western immunoblots measured cytoplasmic phosphorylated and total protein kinase B. Electromobility shift assays measured nuclear activator protein-1. Methylene blue assays measured cell proliferation at 24, 48, and 72 hours after stimulation. Hypoosmotic stress phosphorylated protein kinase B by 10 minutes. Subsequently, hypoosmotic exposure stimulated activator protein-1 by 30 minutes. Pulse exposure to hypoosmotic stress potentiated HepG2 proliferation by 72 hours as compared to both negative controls and LY-inhibited cells (n = 4 per group, P = 0.009 and P = 0.004, respectively; P <0.001 analysis of variance. All three activation events were abolished with LY294002 pretreatment. In HepG2 cells, hypoosmotic stress-induced swelling stimulates proliferation via protein kinase B-mediated activation of activator protein-1. These data delineate a possible mechanism linking changes in cell volume to growth in human liver cancer.