Impact of nursing unit turnover on patient outcomes in hospitals

PURPOSE

The aim of this study was to examine how nursing unit turnover affects key workgroup processes and how these processes mediate the impact of nursing turnover on patient outcomes.

METHODS

A secondary data analysis was used to test the hypothesized model. This study used registered nurse and patient data from 268 nursing units at 141 hospitals collected as part of the Outcomes Research in Nursing Administration (ORNA II) project. Nursing units provided monthly nursing unit turnover rates for 6 consecutive months, and registered nurses completed questionnaires measuring workgroup processes (group cohesion, relational coordination, and workgroup learning). Patient outcome measures included unit-level average length of patient stay, patient falls, medication errors, and patient satisfaction scores.

RESULTS

Nursing units with moderate levels of turnover were likely to have lower levels of workgroup learning compared to those with no turnover (p<.01). Nursing units with low levels of turnover were likely to have fewer patient falls than nursing units with no turnover (p<.05). Additionally, workgroup cohesion and relational coordination had a positive impact on patient satisfaction (p<.01), and increased workgroup learning led to fewer occurrences of severe medication errors (p<.05).

CONCLUSIONS

The findings of this study provide specific information on the operational impact of turnover so as to better design, fund, and implement appropriate intervention strategies to prevent registered nurse exit from nursing units. Further investigation is needed to assess the turnover-outcomes relationship as well as the mediating effect of workgroup processes on this relationship.

CLINICAL RELEVANCE

Managing nursing unit turnover within appropriate levels at the nursing unit is critical to delivering high-quality patient care.

Mandatory overtime regulations and nurse overtime

A descriptive study used data from the 2004 National Sample Survey of Registered Nurses to examine the nature and occurrence of RN mandatory, voluntary overtime, paid on-call, and total work hours and their association with mandatory overtime regulations in United States. About half of the nurses worked more than 40 hrs per week. Nurses working in states regulating mandatory overtime reported lower levels of mandatory overtime hours than states without regulations or states restricting total work hours. The percent of RNs working 61 hrs and over per week in states without regulations was lower than that in states with regulations. Nurses working in nursing homes reported higher levels of the percentage of mandatory overtime hours worked than those working in hospitals. This suggested that governments need to continuously supervise healthcare institutions, including both hospitals and nursing homes, to ensure adherence to mandatory overtime regulations.

Benefit of downsizing hepatocellular carcinoma in a liver transplant population

BACKGROUND

Long-term results after downstaging hepatocellular carcinoma (HCC) prior to liver transplantation (LT) remain unknown.

AIMS

To investigate dropouts and post-transplant outcome among patients with downstaged HCC by transarterial chemo-lipiodolization (TACL).

METHODS

Between 2000 and 2007, 386 patients with HCC initially exceeding Milan criteria underwent TACL for tumour downstaging and were consecutively enrolled.

RESULTS

Overall, 160 (41.5%) patients achieved successful downstaging of HCC to within Milan criteria. During the follow-up, 82 eventually dropped off the waiting list for LT, with estimated dropout rates at 1, 2 and 5 years of 46.7%, 70.2%, and 87.2%, respectively. The overall post-transplant survival rates at 1, 2 and 5 years were 89.2%, 70.3% and 54.6% and the corresponding rates for recurrence-free survival were 74.7%, 71.8% and 66.3% respectively. Multivariate analysis indentified alpha-fetoprotein (AFP) levels > or = 100 ng/mL at LT (P = 0.003), maximum tumour size > or = 7 cm (P = 0.002) and the lack of complete necrosis by TACL (P = 0.048) as independent predictors of HCC recurrence after LT. Patients with none of these risk factors had an excellent post-transplant outcome, with an 87.5% probability of recurrence-free survival up to 6 years.

CONCLUSIONS

These long-term results may contribute to the database for optimizing management of LT candidates with downstaged HCC. Based on our data, patients with a maximum tumour size <7 cm who achieve complete necrosis together with AFP levels <100 ng/mL at LT may be the best candidates for LT following downstaging using TACL.

Pharmacokinetics of oltipraz in diabetic rats with liver cirrhosis

BACKGROUND AND PURPOSE

The incidence of diabetes mellitus is increased in patients with liver cirrhosis. Oltipraz is currently in trials to treat patients with liver fibrosis and cirrhosis induced by chronic hepatitis types B and C and is primarily metabolized via hepatic cytochrome P450 isozymes CYP1A1/2, 2B1/2, 2C11, 2D1 and 3A1/2 in rats. We have studied the influence of diabetes mellitus on pharmacokinetics of oltipraz and on expression of hepatic, CYP1A, 2B1/2, 2C11, 2D and 3A in rats with experimental liver cirrhosis.

EXPERIMENTAL APPROACH

Oltipraz was given intravenously (10 mg x kg(-1)) or orally (30 mg x kg(-1)) to rats with liver cirrhosis induced by N-dimethylnitrosamine (LC rats) or with diabetes, induced by streptozotocin (DM rats) or to rats with both liver cirrhosis and diabetes (LCD rats) and to control rats, and pharmacokinetic variables measured. Protein expression of hepatic CYP1A, 2B1/2, 2C11, 2D and 3A was measured using Western blot analysis.

KEY RESULTS

After i.v. or p.o. administration of oltipraz to LC and DM rats, the AUC was significantly greater and smaller, respectively, than that in control rats. In LCD rats, the AUC was that of LC and DM rats (partially restored towards control rats). Compared with control rats, the protein expression of hepatic CYP1A increased, that of CYP2C11 and 3A decreased, but that of CYP2B1/2 and 2D was not altered in LCD rats.

CONCLUSIONS AND IMPLICATIONS

In rats with diabetes and liver cirrhosis, the AUC of oltipraz was partially restored towards that of control rats.

Multicenter study of intravenous busulfan, cyclophosphamide, and etoposide (i.v. Bu/Cy/E) as conditioning regimen for autologous stem cell transplantation in patients with non-Hodgkin's lymphoma

The current study aimed to evaluate the efficacy and toxicity of a combination of intravenous busulfan, cyclophosphamide and etoposide (i.v. Bu/Cy/E) as a conditioning regimen prior to autologous hematopoietic stem cell transplantation in patients with non-Hodgkin's lymphoma (NHL). Sixty-four patients with relapsed/refractory (n=36) or high-risk (n=28) lymphoma were enrolled. The high-dose chemotherapy consisted of i.v. Bu (0.8 mg kg(-1) i.v. q 6 h from day -7 to day -5), Cy (50 mg kg(-1) i.v. on day -3 and day -2) and E (400 mg m(-2) i.v. on day -5 and day -4). The median age was 43 (range 18-65) years, and 39 patients were male. Diffuse large B-cell lymphoma (40.6%) was the most common histological subtype. All evaluable patients achieved an engraftment of neutrophils (median, day 12) and platelets (median, day 13). Hepatic veno-occlusive disease was observed in four patients (three mild, one moderate grade), and two patients (3.1%) died from treatment-related complications. At a median follow-up of 16.4 months, 15 patients (23.4%) exhibited a relapse or progression, while 13 patients (20.3%) had died of disease. The estimated 3-year overall and progression-free survival for all patients was 72.1 and 70.1%, respectively. In conclusion, the conditioning regimen of i.v. Bu/Cy/E was well tolerated and seemed to be effective in patients with aggressive NHL.

Multicenter study of intravenous busulfan, cyclophosphamide, and etoposide (i.v. Bu/Cy/E) as conditioning regimen for autologous stem cell transplantation in patients with non-Hodgkin's lymphoma

The current study aimed to evaluate the efficacy and toxicity of a combination of intravenous busulfan, cyclophosphamide and etoposide (i.v. Bu/Cy/E) as a conditioning regimen prior to autologous hematopoietic stem cell transplantation in patients with non-Hodgkin's lymphoma (NHL). Sixty-four patients with relapsed/refractory (n=36) or high-risk (n=28) lymphoma were enrolled. The high-dose chemotherapy consisted of i.v. Bu (0.8 mg kg(-1) i.v. q 6 h from day -7 to day -5), Cy (50 mg kg(-1) i.v. on day -3 and day -2) and E (400 mg m(-2) i.v. on day -5 and day -4). The median age was 43 (range 18-65) years, and 39 patients were male. Diffuse large B-cell lymphoma (40.6%) was the most common histological subtype. All evaluable patients achieved an engraftment of neutrophils (median, day 12) and platelets (median, day 13). Hepatic veno-occlusive disease was observed in four patients (three mild, one moderate grade), and two patients (3.1%) died from treatment-related complications. At a median follow-up of 16.4 months, 15 patients (23.4%) exhibited a relapse or progression, while 13 patients (20.3%) had died of disease. The estimated 3-year overall and progression-free survival for all patients was 72.1 and 70.1%, respectively. In conclusion, the conditioning regimen of i.v. Bu/Cy/E was well tolerated and seemed to be effective in patients with aggressive NHL.

The best candidates for transarterial chemotherapy in patients with hepatocellular carcinoma awaiting liver transplantation: a cohort-based characterization of dropout times

BACKGROUND

Although transarterial chemotherapy is used to retard tumour progression for hepatocellular carcinoma (HCC) patients awaiting orthotopic liver transplantation (OLT), information regarding the acceptable waiting time and appropriate patient selection for the therapy is lacking.

AIM

To examine dropout times and determine the best candidates for pre-transplant transarterial therapy in a cohort study.

METHODS

In total, 180 consecutive HCC candidates receiving pre-transplant chemo-lipiodolization were included in the study.

RESULTS

Overall, 70 (38.9%) patients dropped off the waiting list during the median follow-up of 19 months. According to the Child-Pugh (C-P) classification, the estimated dropout rates at 1 and 2 years were 17.2% and 44.8% for the C-P A group and 33.4% and 81.3% for the C-P B/C group, respectively. C-P B/C patients experienced more frequent dropouts than C-P A patients (P < 0.001). Risk factor analysis identified C-P classification to be the strongest predictor of dropout (P < 0.001). On multivariate analysis, alpha-fetoprotein (AFP) >100 ng/mL, tumour size >3 cm and multiple nodules remained independently predictive of dropout for C-P A group (all P < 0.05). Candidates with none of these factors were found to be at the lowest risk of dropout, with only a 22.5% dropout rate up to 41 months.

CONCLUSIONS

This study suggests that Child-Pugh A patients with one nodule <3 cm and AFP < 100 ng/mL may be the best candidates for pre-transplant chemo-lipiodolization, with the lowest dropout rate. However, comparative studies with other therapeutic options are needed to assess the definitive role of transarterial therapy in this setting.

A 13-year longitudinal study of the impact of double mutations in the core promoter region of hepatitis B virus on HBeAg seroconversion and disease progression in patients with genotype C chronic active hepatitis

The pathogenic role of core promoter (CP) mutations (T1762/A1764) of hepatitis B virus (HBV) in hepatitis B e antigen (HBeAg) seroconversion or disease progression remains unclear. We investigated the clinical relevance of these mutants over a long-term follow-up period of up to 15 years. In this longitudinal cohort study, 29 HBeAg-positive patients with biopsy-proved chronic active hepatitis without cirrhosis were regularly monitored for >10 years. The viral isolates were characterized, using the frozen liver tissue obtained on the day of biopsy. Long-term outcomes were compared between patients with and without CP mutations of HBV at baseline. HBV genotyping showed that 100% of study subjects were infected with genotype C HBV. During a median follow-up period of 12.5 years, patients without double CP mutations of HBV at baseline showed a tendency towards achieving an earlier HBeAg seroconversion than those with (6.9 vs 9.4 years, P = 0.062) double CP mutations. Double CP mutations at baseline were also significantly associated with the eventual development of cirrhosis or hepatocellular carcinoma (P = 0.013), whereas the absence of double CP mutations predicted inactive carrier status at the last follow-up (P = 0.027). At 10 years, liver-related tests were also significantly better in patients without double CP mutations of HBV than in those with these mutations, as reflected by higher platelet counts and albumin levels (P = 0.036 and P = 0.044, respectively). Double T1762/A1764 mutations are significantly related to liver deterioration in HBeAg-positive genotype C active hepatitis patients. A longer period of immune clearance coupled with delayed HBeAg seroconversion appears to contribute to disease progression in patients harbouring these mutations in the CP region of HBV.

Hypolipidemic effect of lactobacillus ferment as a functional food supplement

The Lactobacillus ferment used in this study was composed of Lactobacillus fermented wheat, barley and kefir grains. Fermentation increased the CFU of lactic acid bacteria with a reduction in pH value and in the contents of dietary fi ber and glucan. Male SD rats were fed a high fat diet with or without 10% Lactobacillus ferment for 4 weeks. In the Lactic-F group (group fed high-fat diet with Lactobacillus ferment) there was a significantly reduced increase of body weight compared with the HF-control (group fed high-fat diet without Lactobacillus ferment). The food efficiency ratio (FER) tended to be decreased in the Lactic-F group, but there was no significant difference between the Lactic-F and HF-control groups. The perirenal and the epididymal fat weights in the normal dietary group (control) and in the Lactic-F group were significantly lower than those of the HF-control. The serum HDL-cholesterol and the total cholesterol in the Lactic-F group were similar to the control group, and were significantly different from those of the HF-control. These results indicated that the Lactobacillus ferment is a functional material having antiobesity effects, with use as a supplement in functional, health-favoring food.

Structure of influenza a virus promoter and its implications for viral RNA synthesis

Since the worst worldwide pandemic ever recorded — the 1918 Spanish influenza outbreak that killed more than 20 million people — we have achieved significant advances in understanding the influenza virus. However, the fear of such a pandemic remains strong. For example, in 1997, when a lethal influenza variant afflicted eight people in Hong Kong, contributing to the death of six, officials feared the next wave had begun. They managed to solve the problem quickly, however, by destroying all of the poultry in Hong Kong[1].

The relationship of histologic activity to serum ALT, HCV genotype and HCV RNA titers in chronic hepatitis C

It is unclear whether serum ALT levels or virological characteristics of hepatitis C virus(HCV) including HCV genotypes and HCV RNA titers, can reflect the degree of histological injury in chronic hepatitis C. The aim of this study was to investigate the relationships between the levels of histological damage and serum ALT levels, HCV genotypes or circulating HCV RNA titers in chronic hepatitis C. A total of 56 patients underwent liver biopsy and the histological activity index (HAI) was evaluated by Knodell's scoring system. HCV genotype by RT-nested PCR and HCV RNA quantitation by competitive RT-PCR were performed. Thirty-four patients were infected with HCV genotype 1b, 20 patients with genotype 2a, and 2 patients with undetermined type. Serum ALT levels were not positively correlated with total HAI score or HCV RNA titers, but showed a linear correlation with scores of piecemeal necrosis (r=0.32, p<0.05) and portal inflammation (r=0.27, p<0.05). HCV genotype had no significant correlation with RNA titers, HAI score or with serum ALT levels. Also, no statistical relationship was seen between HCV RNA titer and HAI score. These results suggest that liver histology is essential to evaluate the severity of chronic hepatitis C precisely.

SeqA protein aggregation is necessary for SeqA function

The binding of SeqA protein to hemimethylated GATC sequences is important in the negative modulation of chromosomal initiation at oriC, and in the formation of SeqA foci necessary for Escherichia coli chromosome segregation. Using gel-filtration chromotography and glycerol gradient sedimentation, we demonstrate that SeqA exists as a homotetramer. SeqA tetramers are able to aggregate or multimerize in a reversible, concentration-dependent manner. Using a bacterial two-hybrid system, we demonstrate that the N-terminal region of SeqA, especifically the 9th amino acid residue, glutamic acid, is required for functional SeqA-SeqA interaction. Although the SeqA(E9K) mutant protein, containing lysine rather than glutamic acid at the 9th amino acid residue, exists as a tetramer, the mutant protein binds to hemimethylated DNA with altered binding patterns as compared with wild-type SeqA. Aggregates of SeqA(E9K) are defective in hemimethylated DNA binding. Here we demonstrate that proper interaction between SeqA tetramers is required for both hemimethylated DNA binding and formation of active aggregates. SeqA tetramers and aggregates might be involved in the formation of SeqA foci required for the segregation of chromosomal DNA as well as the regulation of chromosomal initiation.

Structural features of an influenza virus promoter and their implications for viral RNA synthesis

The influenza A virus, a severe pandemic pathogen, has a segmented RNA genome consisting of eight single-stranded RNA molecules. The 5' and 3' ends of each RNA segment recognized by the influenza A virus RNA-dependent RNA polymerase direct both transcription and replication of the virus's RNA genome. Promoter binding by the viral RNA polymerase and formation of an active open complex are prerequisites for viral replication and proliferation. Here we describe the solution structure of this promoter as solved by multidimensional, heteronuclear magnetic resonance spectroscopy. Our studies show that the viral promoter has a significant dynamic nature and reveal an unusual displacement of an adenosine that forms a novel (A-A) x U motif and a C-A mismatch stacked in a helix. The characterized structural features of the promoter imply that the specificity of polymerase binding results from an internal RNA loop. In addition, an unexpected bending (46 +/- 10 degrees ) near the initiation site suggests the existence of a promoter recognition mechanism similar to that of DNA-dependent RNA polymerase and a possible regulatory function for the terminal structure during open complex formation.

RPA governs endonuclease switching during processing of Okazaki fragments in eukaryotes

Extensive work on the maturation of lagging strands during the replication of simian virus 40 DNA suggests that the initiator RNA primers of Okazaki fragments are removed by the combined action of two nucleases, RNase HI and Fen1, before the Okazaki fragments join. Despite the well established in vitro roles of these two enzymes, genetic analyses in yeast revealed that null mutants of RNase HI and/or Fen1 are not lethal, suggesting that an additional enzymatic activity may be required for the removal of RNA. One such enzyme is the Saccharomyces cerevisiae Dna2 helicase/endonuclease, which is essential for cell viability and is well suited to removing RNA primers of Okazaki fragments. In addition, Dna2 interacts genetically and physically with several proteins involved in the elongation or maturation of Okazaki fragments. Here we show that the endonucleases Dna2 and Fen1 act sequentially to facilitate the complete removal of the primer RNA. The sequential action of these enzymes is governed by a single-stranded DNA-binding protein, replication protein-A (RPA). Our results demonstrate that the processing of Okazaki fragments in eukaryotes differs significantly from, and is more complicated than, that occurring in prokaryotes. We propose a novel biochemical mechanism for the maturation of eukaryotic Okazaki fragments.

Tripartite structure of Saccharomyces cerevisiae Dna2 helicase/endonuclease

In order to gain insights into the structural basis of the multifunctional Dna2 enzyme involved in Okazaki fragment processing, we performed biochemical, biophysical and genetic studies to dissect the domain structure of Dna2. Proteolytic digestion of Dna2 using subtilisin produced a 127 kDa polypeptide that lacked the 45 kDa N-terminal region of Dna2. Further digestion generated two subtilisin-resistant core fragments of approximately equal size, 58 and 60 kDa. Surprisingly, digestion resulted in a significant (3- to 8-fold) increase in both ATPase and endonuclease activities compared to the intact enzyme. However, cells with a mutant DNA2 allele lacking the corresponding N-terminal region were severely impaired in growth, being unable to grow at 37 degrees C, indicating that the N-terminal region contains a domain critical for a cellular function(s) of Dna2. Analyses of the hydrodynamic properties of and in vivo complex formation by wild-type and/or mutant Dna2 lacking the N-terminal 45 kDa domain revealed that Dna2 is active as the monomer and thus the defect in the mutant Dna2 protein is not due to its inability to multimerize. In addition, we found that the N-terminal 45 kDa domain interacts physically with a central region located between the two catalytic domains. Our results suggest that the N-terminal 45 kDa domain of Dna2 plays a critical role in regulation of the enzymatic activities of Dna2 by serving as a site for intra- and intermolecular interactions essential for optimal function of Dna2 in Okazaki fragment processing. The possible mode of regulation of Dna2 is discussed based upon our recent finding that replication protein A interacts functionally and physically with Dna2 during Okazaki fragment processing.

Serum after partial hepatectomy stimulates iNOS gene transcription via downstream NF-kappa B site

It has been known that the expression of inducible nitric oxide synthase (iNOS) is up-regulated during hepatic regeneration. The present study characterized the molecular mechanisms involved in the transcriptional activation of iNOS gene by using the serum after partial hepatectomy (post-PH serum) in vitro. The post-PH serum rapidly induced iNOS mRNA expression, which was blocked by anti-tumor necrosis factor-alpha (TNF-alpha) antibody in BNL CL.2 cells, murine embryonic liver cell line. In addition, EMSAs using a NF-kappa B-specific oligomer showed that the up-regulated iNOS mRNA expression in cells treated with post-PH serum correlated with transient activation of NF-kappa B complex (p50/p65 heterodimer). Transient transfection of BNL CL.2 cells with iNOS promoter linked to a CAT reporter gene showed the transcriptional activation of iNOS promoter by post-PH serum. Furthermore, site-directed mutational analysis of the two NF-kappa B sites individually or in combination revealed that iNOS expression by post-PH serum is regulated by the downstream NF-kappa B site, but not by upstream NF-kappa B site. Taken together, these results suggest that the downstream NF-kappa B site acts as an essential component for the iNOS expression by post-PH serum during hepatic regeneration.

Design of a PC-based multimedia telemedicine system for brain function teleconsultation

During time-critical brain surgery, the detection of developing cerebral ischemia is particularly important because early therapeutic intervention may reduce the mortality of the patient. The purpose of this system is to provide an efficient means of remote teleconsultation for the early detection of ischemia, particularly when subspecialists are unavailable. The hardware and software design architecture for the multimedia brain function teleconsultation system including the dedicated brain function monitoring system is described. In order to comprehensively support remote teleconsultation, multi-media resources needed for ischemia interpretation were included: EEG signals, CSA, CD-CSA, radiological images, surgical microscope video images and video conferencing. PC-based system integration with standard interfaces and the operability over the Ethernet meet the cost-effectiveness while the modular software was customized with a diverse range of data manipulations and control functions necessary for shared workspace and standard interfaces.

Expression of cyclooxygenase-2 (COX-2) in hepatocellular carcinoma and growth inhibition of hepatoma cell lines by a COX-2 inhibitor, NS-398

Cyclooxygenase-2 (COX-2) has been suggested to be associated with carcinogenesis. In hepatocellular carcinoma (HCC), the expression pattern of COX-2 protein has been well correlated with the differentiation grade, suggesting that abnormal COX-2 expression plays an important role in hepatocarcinogenesis. We investigated the expression pattern and clinical significance of COX-2 in HCC tissues. In addition, we evaluated the efficacy of a selective COX-2 inhibitor, NS-398, in three hepatoma cell lines. Thirty-six HCC tissues, 15 hepatoma cell lines, 1 colorectal cell line (HT-29), and 1 fibroblast cell line (SV80) were included in the study. We evaluated serological tests and histological and radiological evaluations of HCC tissues. Immunohistochemical staining for COX-2 was performed on 36 HCC tissues and 17 cancer cell lines. A cell viability assay for growth inhibition of NS-398 in five cell lines was performed. Immunohistochemically, all six well-differentiated HCCs were positive, whereas 83% (10 of 12) of the poorly differentiated HCCs were negative. There was no significant relationship between the intensity of COX-2 expression and the level of alpha-fetoprotein, tumor size, presence of portal vein thrombosis, tumor capsule and metastasis, Tumor-Node-Metastasis staging, and growth types (P > 0.05). According to the cell viability assay, NS-398 suppressed the growth of all cell lines, independent of the degree of COX-2 expression. The inhibitory effect on each cell line was identified in 10 microM NS-398 and was significantly strong in 100 microM NS-398. All cell lines exhibited apoptosis, which was identified by 4'-6-diamidino-2-phenylindole staining. In conclusion, COX-2 may be a determinant of the differentiation grade of HCC, and the inhibition of COX-2 can induce growth suppression of hepatoma cell lines via induction of apoptosis.

Cortical actin filaments in guard cells respond differently to abscisic acid in wild-type and abi1-1 mutant Arabidopsis

Cortical actin filaments in guard cells of Commelina communis L. show signal-specific organization during stomatal movements [S.-O. Eun and Y. Lee (1997) Plant Physiol 115: 1491-1498; S.-O. Eun and Y. Lee (2000) Planta 210: 1014-1017]. To study the roles of actin in signal transduction, it is advantageous to use Arabidopsis thaliana (L.) Heynh., an excellent model plant with numerous well-characterized mutants. Using an immunolocalization technique, we found that actin deployments in guard cells of A. thaliana were basically identical to those in C. communis: actin proteins were assembled into radial filaments under illumination, and were disassembled by ABA. In addition, we examined actin organization in an ABA-insensitive mutant (abi1-1) to test the involvement of protein phosphatase 2C (PP2C) in the control of actin structure. A clear difference was observed after ABA treatment, namely, neither stomatal closing nor depolymerization of actin filaments was observed in guard cells of the mutant. Our results indicate that PP2C participates in ABA-induced actin changes in guard cells.

Phlegmonous enteritis in a patient with congestive heart failure and colon cancer

Phlegmonous enteritis is a rare infective inflammatory disease of the intestine, predominantly involving the submucosal layer. It is difficult to diagnose and often fatal. Its association with alcoholism and various liver diseases, although rarely reported, is well documented. We report a case of phlegmonous enteritis in a male patient with congestive heart failure and colon cancer, and describe the ultrasonographic and CT findings.

One-year follow-up of Graves' disease treatment by four different protocols of radioiodine administration

BACKGROUND

Studies have been performed in order to assess a treatment with 131I able to induce a consistent improvement in Graves' hyperthyroidism.

METHODS

EXPERIMENTAL DESIGN

For this purpose, four different protocols based on four different doses of radioiodine have been tested in Graves' disease patients. Patients never submitted previously to antithyroid drug treatment were given 1 mCi/10 gm of the estimated thyroid weight (group I; n = 50). Group II (n = 48) included patients not previously treated with antithyroid drugs and who were given doses of iodine based on a formula taking into account the rate of thyroid iodine uptake, i.e. 131I dose = microCi/gm of the estimated thyroid weight x 100/24 hrs 131I uptake (%). Patients previously submitted to antithyroid drug therapy were treated with radioiodine whose dose was calculated according to the formula reported above, but the dose was increased in order to overcome the possible resistance of this kind of patients to the effect of 131I. One group (group III; n = 24) received the calculated dose plus 1 microCi/gm of the estimated thyroid weight. Finally, group IV (n = 27) received the calculated dose plus 0.25 microCi/gm of the estimated thyroid weight.

RESULTS

The analysis of the patients one year later demonstrated that groups I and II presented the higher percent of euthyroid patients (60% and 58%, respectively) followed by group IV (37%) and group III (29.2%). The percent of patients still exhibiting hyperthyroidism was 28% in group I, 26% in group IV, 12.5% in group III and 8.3% in group II. The highest number of hypothyroid patients was present in group III (58.3%) followed by group IV (37%), group II (33.3%) and group I (12%).

CONCLUSIONS

The data here presented suggest that protocols I and II based on relatively low doses of radioiodine are rather effective in reducing Graves' hyperthyroidism in patients not submitted previously to antithyroid drug therapy. The most satisfactory therapy seems that utilized in protocol II, that in front of a fair amount of euthyroid patients (58.3%) presents a very low number of subjects still hyperthyroid (8.3%). However, the number of patients who became hypothyroid (33.3%) as a consequence of the therapy was too high. Hopefully, a better design of the protocol will reduce this figure. The high incidence of hyperthyroidism observed in groups III and IV submitted to a therapy with 131I doses consistently higher than those utilized in groups I and II seems to confirm the hypothesis that hyperthyroid subjects submitted to a therapy with antithyroid drugs become rather resistant to a radioiodine treatment.

Characterization of the enzymatic properties of the yeast dna2 Helicase/endonuclease suggests a new model for Okazaki fragment processing

The Saccharomyces cerevisiae Dna2, which contains single-stranded DNA-specific endonuclease activity, interacts genetically and physically with Fen-1, a structure-specific endonuclease implicated in Okazaki fragment maturation during lagging strand synthesis. In this report, we investigated the properties of the Dna2 helicase/endonuclease activities in search of their in vivo physiological functions in eukaryotes. We found that the Dna2 helicase activity translocates in the 5' to 3' direction and uses DNA with free ends as the preferred substrate. Furthermore, the endonucleolytic cleavage activity of Dna2 was markedly stimulated by the presence of an RNA segment at the 5'-end of single-stranded DNA and occurred within the DNA, ensuring the complete removal of the initiator RNA segment on the Okazaki fragment. In addition, we demonstrated that the removal of pre-existing initiator 5'-terminal RNA segments depended on a displacement reaction carried out during the DNA polymerase delta-catalyzed elongation of the upstream Okazaki fragments. These properties indicate that Dna2 is well suited to remove the primer RNA on the Okazaki fragment. Based op this information, we propose a new model in which Dna2 plays a direct role in Okazaki fragment maturation in conjunction with Fen-1.

The endonuclease activity of the yeast Dna2 enzyme is essential in vivo

Dna2 is a multifunctional enzyme in yeast that possesses endonuclease activity well suited to remove RNA-DNA primers of Okazaki fragments, raising the question of whether endonuclease activity is essential for in vivo Dna2 function. Systematic site-directed mutations of amino acid residues in Saccharomyces cerevisiae DNA2 conserved in the central region of many eukaryotic DNA2 homologs allowed us to identify mutant dna2 alleles that were divided into three groups based on the viability of the mutant cells: (i) viable; (ii) inviable only when expression was repressed; (iii) inviable. Biochemical analyses of recombinant mutant Dna2 proteins isolated from the latter two groups revealed that they possessed normal ATPase/helicase activity, but were impaired in their endonuclease activity. Cells expressing mutant Dna2 enzymes partially impaired in endonuclease activity were viable, but were unable to grow when expression of their mutant Dna2 enzymes was further reduced. Their growth was restored when the mutant Dna2 proteins decreased in nuclease activity were induced to overexpress. In contrast, mutant Dna2 proteins lacking endonuclease activity did not allow cells to grow under any conditions tested. These in vivo and in vitro results demonstrate that the endonuclease activity of Dna2 is essential for Okazaki fragment processing.

Genetic analyses of Schizosaccharomyces pombe dna2(+) reveal that dna2 plays an essential role in Okazaki fragment metabolism

In this report, we investigated the phenotypes caused by temperature-sensitive (ts) mutant alleles of dna2(+) of Schizosaccharomyces pombe, a homologue of DNA2 of budding yeast, in an attempt to further define its function in vivo with respect to lagging-strand synthesis during the S-phase of the cell cycle. At the restrictive temperature, dna2 (ts) cells arrested at late S-phase but were unaffected in bulk DNA synthesis. Moreover, they exhibited aberrant mitosis when combined with checkpoint mutations, in keeping with a role for Dna2 in Okazaki fragment maturation. Similarly, spores in which dna2(+) was disrupted duplicated their DNA content during germination and also arrested at late S-phase. Inactivation of dna2(+) led to chromosome fragmentation strikingly similar to that seen when cdc17(+), the DNA ligase I gene, is inactivated. The temperature-dependent lethality of dna2 (ts) mutants was suppressed by overexpression of genes encoding subunits of polymerase delta (cdc1(+) and cdc27(+)), DNA ligase I (cdc17(+)), and Fen-1 (rad2(+)). Each of these gene products plays a role in the elongation or maturation of Okazaki fragments. Moreover, they all interacted with S. pombe Dna2 in a yeast two-hybrid assay, albeit to different extents. On the basis of these results, we conclude that dna2(+) plays a direct role in the Okazaki fragment elongation and maturation. We propose that dna2(+) acts as a central protein to form a complex with other proteins required to coordinate the multienzyme process for Okazaki fragment elongation and maturation.

The relationship between virological characteristics of hepatitis C virus (HCV) and reactivity to the regional specific proteins of HCV

BACKGROUND

Although the polyproteins of hepatitis C virus(HCV) are processed and formed in nearly equimolar amounts, individual functional proteins have a discrepancy in their time of appearance following HCV infection and eliciting immune response. This study was conducted to compare the reactivity toward regional specific HCV protein in relation to virological characteristics, including HCV genotype and HCV replication.

METHODS

Sera from forty-five patients with chronic HCV infection were analyzed through the experiments of the recombinant immunoblot assay(RIBA-2), HCV genotyping and HCV RNA quantitation.

RESULTS

The frequencies of seropositivity to C22-3, C33C, C100-3 and 5-1-1 proteins were 91.1%, 91.1%, 64.4% and 53.3%, respectively, of all the patients, and thus the antibodies to C22-3 and C33C proteins were found more frequently (p < 0.05). The antibody responses between core or NS3 proteins and NS4 proteins showed more discrepancy in the HCC group than that in the CH group, implying a possibility of oncogenic potential of core or NS3 gene in hepatocarcinogenesis. The detection rate of antibodies to C22-3 and C33C, in accordance with serum HCV RNA levels, was significantly higher in highly viremic patients than that in low viremic patients (p < 0.05). Antibodies to C22-3, C33C, C100-3 and 5-1-1 were also found more frequently in patients with HCV genotype 1b, compared to those with HCV genotype 2a (p < 0.05).

CONCLUSION

These results suggest that antibody detection of HCV may depend on the virological characteristics of HCV, the levels of HCV replication and HCV genotype and, therefore, HCV RNA detection using RT-PCR technique is essential for confirmatory diagnosis for HCV infection. Furthermore, the HCV core or NS3 Protein may play important role in hepatocarcinogenesis.