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Biomedical subjects

G Bukholm

Publications and source records attributed to G Bukholm.

At least 19 recordsLinked to original sources
PubMed2006

Does Pseudomonas aeruginosa colonization influence morbidity and mortality in the intensive care unit patient? Experience from an outbreak caused by contaminated oral swabs.

BACKGROUND: Contaminated oral swabs caused a nationwide monoclonal Pseudomonas aeruginosa outbreak involving 27 Norwegian hospitals. The aim of the study was to study the consequences on mortality and morbidity of the introduction of this P. aeruginosa strain to intensive care unit (ICU) patients. METHODS: Forty-four out of 96 patients admitted to the general ICU of Akershus University Hospital during the outbreak, ventilated for more than 24 h and with at least one microbiological sample, were included and followed until death or hospital discharge. All isolated P. aeruginosa strains were genotyped. Demographic data, admission diagnosis, Simplified Acute Physiology Score II (SAPS II), Sequential Organ Failure Assessment (SOFA) score, comorbidities, and antibiotics used in the first week were recorded. RESULTS: The outbreak strain was found in 18 patients (41%) of whom seven became infected. Median time to the first positive culture was 4 days. These 18 patients spent a significantly longer time on mechanical ventilation (P =0.03) and had a significantly higher hospital mortality, 55.5% vs. 19.2% (P =0.03), than non-colonized patients. The number of patients with severe underlying disease was significantly higher (P =0.01) and the decline in SOFA score was significantly slower in the pseudomonas group (P =0.02). Irrespective of colonization status, patients with severe underlying disease had a significantly higher mortality (58%) than those without (16%) (P =0.009). CONCLUSION: Use of contaminated oral swabs led to a high rate of early airways colonization. Patients with severe underlying disease were more likely to become colonized, but whether colonization has any influence on hospital mortality requires further study.

APACHE↗
PubMed2006

Increased incidence of methicillin-resistant Staphylococcus aureus ST80, novel ST125 and SCCmecIV in the south-eastern part of Norway during a 12-year period.

A retrospective population-based study of genotypes of methicillin-resistant Staphylococcus aureus (MRSA) was performed during the period 1991-2003 in two counties in the south-eastern part of Norway. Isolates of MRSA from all individuals in the two counties in whom MRSA was detected were genotyped by means of multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, staphylococcal protein A gene (spa) typing and amplified fragment length polymorphism (AFLP) analysis. Until 1999, only sporadic cases of MRSA infection were reported in these counties, but the incidence increased during the following years. Nine new MLST types were identified in this study. The predominant strains were ST239-MRSA-III, the novel ST125-MRSA-IV, and the central European community-acquired strain ST80-MRSA-IV reported previously. ST80-MRSA-IV was introduced into the two counties in 1997, and the incidence of infections has increased since 2000, so that ST80-MRSA-IV is now the commonest MRSA strain in the region. An increase in MRSA clones carrying SCCmecIV has occurred during recent years, which could indicate a shift in the MRSA population in Norway from hospital-acquired MRSA to community-acquired-MRSA.

Bacterial Proteins↗
PubMed2006

The prognostic value and overexpression of cyclin A is correlated with gene amplification of both cyclin A and cyclin E in breast cancer patient.

UNLABELLED: Deregulation of cell cycle control is a hallmark of cancer. The primary cyclins (A, B1, D1, D3 and E) are crucial for cell cycle progression. Secondary cyclins (C and H) have putative indirect effects on cell cycle propulsion and are not previously evaluated in breast cancer. We have examined protein expression and gene amplification of cyclins in breast carcinomas and correlated the findings with clinical follow-up data. We have previously demonstrated that over-expression of cyclin A is associated with poor prognosis in breast cancer patients. In this study we wanted to evaluate the mechanisms behind overexpression of cyclin A, as well as the impact of other cyclins, both at the gene level and at the protein level, on prognosis of breast cancer patients. The impact of TP53 gene mutations on gene amplification of cyclins was also evaluated. METHODS: Real-Time Quantitative PCR was used to detect gene amplification of cyclins in tumour tissue from 86 patients operated for invasive breast carcinomas, while immunohistochemistry was applied to detect protein expression of the same cyclins. RESULT: Of the 80-breast tumour samples available for cyclin A gene amplification analyses, 26.7% (23/80) was defined to have cyclin A gene amplification. 37.2% (32/79) had cyclin B1 gene amplification, 82.6% (71/82) of the samples harboured amplification of cyclin C gene, 74.4% (64/82) had cyclin D1 gene amplification, 41.9% (36/86) had cyclin D3 gene amplification, 29.1% (25/81) of the patients had cyclin E gene amplification and 9.3% (8/86) of the samples showed amplification of the cyclin H gene. When correlation between gene amplification and protein expression was evaluated, we observed a statistical significant correlation between gene amplification and protein expression of cyclin A (p=0.009) and cyclin D3 (p<0.001). However, the correlation between gene amplification and protein expression of cyclin A, as well as the prognostic value of cyclin A overexpression, was affected by gene amplification of cyclin E. Gene amplification of none of the other cyclins was associated with patient prognosis. There was a statistical significant correlation between TP53 gene mutations and gene amplification of cyclins A, D3 and B1. No correlation was observed between gene amplification of secondary cyclins (H and C) and TP53 gene mutations. CONCLUSIONS: The overexpression of cyclin A is correlated to gene amplification of both cyclin A and cyclin E. Over-expression of cyclin A is associated with poor prognosis in breast cancer patients. When analysed in a multivariate analyses model, gene amplification as well as protein expression of none of the other cyclins than cyclin A are associated with patient prognosis in breast carcinomas. TP53 gene mutation seems to correlate with gene amplification of primary, but not secondary cyclins.

Breast Neoplasms↗
PubMed2005

Alcohol-based hand disinfection: a more robust hand-hygiene method in an intensive care unit.

This study involved observation of hand-hygiene behaviour and evaluation of the effect of alcohol-based hand disinfection and handwashing with plain liquid soap on microbial flora. The study was performed in a combined medical and surgical intensive care unit. We demonstrated a crude compliance of hand hygiene of 50.4%, which was only performed adequately in 20.8% of cases. Of this group, handwashing and hand-disinfection procedures were performed properly 34.0% and 71.6% of the time, respectively. Hand samples for bacteriological examinations with the glove juice method demonstrated that whilst handwashing was sensitive to the way in which hand hygiene was performed, alcohol-based hand disinfection was less sensitive to such performance. Our study demonstrated that alcohol-based hand disinfection is a robust hand-hygiene method with many advantages in a practical setting. It is very feasible for use in hospital wards.

Adult↗
PubMed2005

Expression and gene amplification of primary (A, B1, D1, D3, and E) and secondary (C and H) cyclins in colon adenocarcinomas and correlation with patient outcome.

BACKGROUND/AIMS: Deregulation of cell cycle control is a hallmark of cancer. The primary cyclins (A, B1, D1, D3, and E) are crucial for cell cycle progression. Secondary cyclins (C and H) have putative indirect effects on cell cycle progression and have not previously been evaluated in colon cancer. This study examined cyclin protein expression and gene amplification in colon adenocarcinoma and the correlation with patient outcome. METHODS: Immunohistochemistry and real time quantitative polymerase chain reaction were used to determine cyclin expression and gene amplification in 219 tumours. The results were compared with clinical variables and patient outcomes. RESULTS: Cyclin H was overexpressed in all tumours, cyclin C in 88%, cyclin B1 in 58%, cyclin A in 83%, cyclin D3 in 36%, cyclin E in 25%, and cyclin D1 in 11% of the tumours. Extra gene copies of cyclin A were seen in 6.2% of the tumours, cyclin B1 in 9%, cyclin C in 26.9%, cyclin D1 in 55%, cyclin D3 in 20.5%, cyclin E in 19.1%, and cyclin H in 5.1%. A significant correlation between protein overexpression and gene amplification was seen for cyclin C only. High expression of cyclin A was independently associated with improved survival. Amplification of cyclin C was independently associated with an unfavourable prognosis. CONCLUSIONS: Amplification of the cyclin C gene was related to an unfavourable prognosis and high protein expression of cyclin A was associated with a better outcome in colon adenocarcinoma.

Adenocarcinoma↗
PubMed2003

Presence of isolated tumour cells in mesenteric lymph nodes predicts poor prognosis in patients with stage II colon cancer.

AIM: Most patients with stage I and stage II colon adenocarcinomas do not have disseminated disease, and the group is not offered adjuvant therapy. However, more than 30% of stage II colon adenocarcinoma patients get metastases to remote organs. Thus, it is important to identify patients in this group at risk of disease relapse. PATIENTS AND METHODS: We have examined the prognostic value of isolated tumour cells (ITC) in mesenteric lymph nodes in a consecutive series of 156 colon carcinoma patients with stage II disease. Immunohistochemistry, using antibodies to cytokeratins, and morphology were used to identify presence of ITC. RESULTS: ITC were detected in 59 (37.8%) patients. Presence of ITC in mesenteric lymph nodes was independently associated with reduced relative survival both in univariate (p=0.0199) and in a multivariate analysis (p=0.041). CONCLUSION: The results strongly suggest that presence of ITC in mesenteric lymph nodes is associated with reduced relative survival in colon carcinoma patients stage II, and that detection of ITC may be important in treatment of these patients.

Adenocarcinoma↗
PubMed2003

Association between histology grade, expression of HsMCM2, and cyclin A in human invasive breast carcinomas.

AIM: Increased proliferation of tumour cells has prognostic value in human invasive breast carcinomas (IBCs), and high histology grade and cyclin A expression, which may reflect high proliferation rate, are associated with poor prognosis. Expression of HsMCM2 is related to cell proliferation. This study evaluates the correlation between the expression of cyclins A, D1, D3, and E, Ki-67, proliferating cell nuclear antigen (PCNA), histology grade, and HsMCM2 expression, in addition to the independent prognostic value of HsMCM2 expression in human IBCs. METHODS: Immunohistochemistry to evaluate HsMCM2, Ki-67, and PCNA expression in tumours from 147 patients with IBC. RESULTS: Nuclear staining for HsMCM2 was seen in 10-30% of the tumour cells in 30 samples, in 30-70% in 40 samples, in > 70% in 44 samples, and in < 10% in 33 samples. One way ANOVA showed a significant association between expression of HsMCM2 and cyclin A, D3, E, histology grade, and Ki-67. A borderline correlation was seen between HsMCM2 and PCNA. In multivariate analysis, the only association was with cyclin A, in addition to a borderline association with histology grade. In a Cox regression hazards model, expression of HsMCM2 was associated with poor patient survival, although it lost its independent prognostic value when cyclin A expression was included. Ki-67 and PCNA expression were not associated with patient survival. CONCLUSION: Cyclin A expression is independently associated with HsMCM2 expression, histology grade, and Ki-67. HsMCM2 expression is associated with poor patient survival, although it loses prognostic value when adjusted for cyclin A.

Biomarkers, Tumor↗
PubMed2001

Over-expression of cyclin A is highly associated with early relapse and reduced survival in patients with primary breast carcinomas.

Progression through the mammalian cell cycle is facilitated by cyclin-cyclin-dependent kinase (cdk) complexes, which are activated at specific points during the cell cycle. Alteration in cyclin-cdk complexess may lead to altered cell cycle and tumorigenesis. In this study, we analyzed expression of cyclins A, D1, D3 and E in tumor tissue from 170 patients with primary invasive breast carcinomas. Immunohistochemical methods were used to detect protein expression of these cyclins. We detected positive immunoreactivity in 55 (32%), 22 (13%), 38 (22%) and 37 (21.8%) of the samples for cyclins A, D1, D3 and E, respectively. A highly statistically significant association was observed between expression of cyclin A and early relapse (p = 0.001 univariate analysis, p = 0.006 multivariate analysis) as well as cancer-specific death (p < 0.0001) during the follow-up time. No association was observed between cyclin D1 or cyclin E, respectively, and relapse of disease or survival, while cyclin D3 over-expression was associated with development of metastases during follow-up (p = 0.005 univariate analysis, p = 0.01 multivariate analysis). However, cyclin D3 did not show any statistically significant association when cancer-specific death was examined in a multivariate analysis (Cox regression for survival function).

Adult↗
PubMed2001

Complement activation directly induced by Helicobacter pylori.

BACKGROUND AND AIMS: Helicobacter pylori is a frequent gram-negative colonizer of the human stomach. Its interaction with complement may be involved in the pathogenesis of chronic gastritis, and was mechanistically studied in vitro. METHODS: Four H. pylori strains, 2 cytotoxin-associated genes (cag)A+ and 2 cagA-, were isolated from infected patients. Bacteria or purified H. pylori lipopolysaccharides (LPSs) were incubated with nonimmune serum at 37 degrees C; the activation products C3b/iC3b/C3c (C3bc) and terminal complement complex (TCC) were then quantified by immunoassays. The serum sensitivity of 1 strain (L01, cagA+) was tested by counting the numbers of colony-forming units. RESULTS: All strains and LPSs generated large amounts of C3bc and TCC. Blocking of the classic complement pathway by the calcium chelator ethylene glycol tetraacetic acid (EGTA) markedly reduced the complement products, suggesting that H. pylori and its LPSs directly engage the classic activation pathway. H. pylori was shown to be serum sensitive, but 30% or more nonimmune serum was necessary to induce marked killing. After 5 minutes, swelled bacteria coated with C3bc and TCC were shown. CONCLUSIONS: H. pylori is complement sensitive and activates the classic pathway even in the absence of specific antibodies. Released cell wall constituents such as LPSs can activate complement and may explain why this bacterium induces gastric pathology without invading the mucosa.

Antibodies, Bacterial↗
PubMed2001

Phase variation in the Helicobacter pylori phospholipase A gene and its role in acid adaptation.

Previously, we have shown that Helicobacter pylori can spontaneously and reversibly change its membrane lipid composition, producing variants with low or high content of lysophospholipids. The "lyso" variant contains a high percentage of lysophospholipids, adheres better to epithelial cells, and releases more proteins such as urease and VacA, compared to the "normal" variant, which has a low content of lysophospholipids. Prolonged growth of the normal variant at pH 3.5, but not under neutral conditions, leads to enrichment of lyso variant colonies, suggesting that the colony switch is relevant to acid adaptation. In this study we show that the change in membrane lipid composition is due to phase variation in the pldA gene. A change in the (C) tract length of this gene results in reversible frameshifts, translation of a full-length or truncated pldA, and the production of active or inactive outer membrane phospholipase A (OMPLA). The role of OMPLA in determining the colony morphology was confirmed by the construction of an OMPLA-negative mutant. Furthermore, variants with an active OMPLA were able to survive acidic conditions better than variants with the inactive form. This explains why the lyso variant is selected at low pH. Our studies demonstrate that phase variation in the pldA gene, resulting in an active form of OMPLA, is important for survival under acidic conditions. We also demonstrated the active OMPLA genotype in fresh isolates of H. pylori from patients referred to gastroscopy for dyspepsia.

Acids↗
PubMed2000

Lipid profiles of Helicobacter pylori colony variants.

A phase variation in Helicobacter pylori has been previously described. In one phase the bacterium had a cell wall lipid content typical for gram-negative bacteria (HpL), whereas in the other phase the bacterium was found to have a cell wall with increased amounts of lysophospholipids (HpS). The conversion is spontaneous, but could also be induced by acid (HpS(ind)) and was associated with in vitro release of Vac A and urease. The purpose of the present study was to determine the full phospholipid content of the cell wall to indicate a molecular mechanism of the colony variation. There were no appreciable differences between the lipid profiles of HpS and HpS(ind), while there were major differences between HpL and the S-variant. In the S-variant, lysophospholipids constituted about 50% of the total phospholipids, as compared to less than 2% in the L-variant. The proportion of total and individual cholesteryl glucosides also showed considerable changes. HpL was dominated by the phosphate-linked cholesteryl glucoside (72%) while the acylated cholesteryl glucoside was the main cholesteryl glucoside of the S-variant (65%). Our results demonstrate a dramatic change in cell wall properties after acid induction and spontaneously in vitro, and suggest some molecular mechanisms for this variation from an in vitro non-virulent to a virulent variant.

Cardiolipins↗
PubMed1997

Colony variation of Helicobacter pylori: pathogenic potential is correlated to cell wall lipid composition.

BACKGROUND: Differences in expression of disease after infection with Helicobacter pylori have so far been connected with host factors and bacterial interstrain variation. In this study, spontaneous and ecology-mediated intrastrain variation was examined. METHODS: Four clinical isolates of H. pylori were shown to give rise to two colony forms. Bacterial morphology was examined by electron microscopy. Bacterial fractions were examined for proteins using ion exchange chromatography and SDS-PAGE; for lipids using thin-layer chromatography, lipid anion-exchange chromatography, column chromatography on silica gel, 31P-NMR, gas chromatography and mass spectrometry. Bacterial in vitro invasiveness and adhesiveness were examined in two different systems, and urease and VacA toxin were assayed by Western blot analysis. RESULTS: H. pylori was shown to give rise to two colony forms: at normal pH the population was dominated by L colonies. One strain was chosen for further studies. Bacteria from L colonies retained VacA toxin and urease, did not invade or adhere to epithelial cells, and contained normal quantities of phosphatidylethanolamine. In a small frequency, spontaneous S colonies were formed. Bacteria from these colonies released VacA and urease, adhered to and invaded epithelial cells and contained increased amounts of lysophosphatidyl ethanolamine and phosphatidyl serine. After addition of HCl to the culture medium (pH6), almost only S colonies were formed. The results demonstrate that environmental factors, such as HCl, can change the bacterial cell wall, and thereby enhance expression of virulence factors of H. pylori in vitro. A similar in vivo variation would have implications for our understanding of the interaction between HCl secretion in the gastric mucosa and H. pylori in the development of peptic ulcer disease.

Bacterial Adhesion↗
PubMed1996

Human interferon reduces surface expression but not total production of herpes simplex virus type 1 glycoproteins gC and gE in heterologous hamster cells.

The effect of interferon (IFN) on herpes simplex virus type 1 (HSV-1)-induced glycoproteins gC and gE was investigated in a heterologous IFN/cell model. In this model, the effect on surface expression of the glycoproteins could be studied separately from the effect on virus multiplication. Pretreatment of baby hamster kidney cells (BHK) with heterologous human leukocyte IFN suppressed surface expression of HSV-1-encoded gC and gE but had no influence on total production of the glycoproteins. This was in contrast to the effect on human embryonic fibroblast cells (HE) (homologous IFN and cells), where surface expression as well as total production of glycoproteins were reduced. The surface expression was demonstrated by antibody-sensitized monodisperse polystyrene beads, and immunoblotting and two-dimensional electrophoretic analysis of radioisotope-labeled proteins were used to study the total production.

Animals↗
PubMed1995

[Revolution in diagnostic microbiology. Needs, driving forces and consequences].

Introducing molecular biological technology into medical microbiology promotes deeper insight into the epidemiology, pathogenesis, diagnostics and treatment of infectious diseases. New technology has helped to highlight the complicated biological interaction between host and microbes and has created a need for more advanced technology both in microbiological diagnostics and in microbiological science. Extra-professional factors like the high prestige of new techniques have also been of considerable significance. Medical microbiologists will become an important link between the inventors of new technology and the physicians who diagnose and treat the patients. Through these contacts and their diagnostic laboratory work, they will become important generators and communicators of knowledge. In this connection it will be important to represent reason in introducing technology in medical microbiological diagnostics. Since patients are expected to play a more active part in health care, communicating knowledge to patients and the population in general will become an obligation.

Genetic Techniques↗
PubMed1995

Shigella flexneri adherence to and multiplication in coxsackie B1 virus-infected HEp-2 cells.

Coxsackie B1 virus infection enhances the susceptibility of in vitro cultured HEp-2 cells to invasiveness by Shigella flexneri. We have studied the effect of viral infection on two phases of the invasiveness. Only a minor part was mediated by enhanced bacterial adherence to the cells, and the intracellular multiplication was unaffected by the virus. Enhanced adherence was not dependent on the presence of the gene product of the 140 Md virulence associated plasmid. Our data indicate that enhanced invasiveness induced by viral infection is mediated by an effect on other phases of the invasiveness.

Bacterial Adhesion↗
PubMed1994

Rapid detection of cytomegalovirus infection in immunocompromised patients.

Several routinely employed diagnostic methods were analysed for their usefulness in aiding an early and rapid diagnosis of human cytomegalo-virus infection in immunocompromised patients. Clinical samples obtained during an 18-month period were examined by conventional culture, the shell vial method, detection of pp65 antigen and the polymerase chain reaction. Detection of pp65 antigen in peripheral leukocytes was the most useful method for rapid detection of infection at an early stage. Results of other rapid detection methods, the shell vial method and the polymerase chain reaction, gave useful support, while results obtained by conventional culture were not available until after the initiation of therapy. Only a small proportion of serological tests provided useful information for determining whether to treat the patient.

Antigens, Viral↗
PubMed1994

Infection with human cytomegalovirus enhances bacterial adhesiveness and invasiveness in permissive and semipermissive cells.

The effect of human cytomegalovirus (HCMV) infection on adhesiveness and invasiveness of Salmonella typhimurium was examined in cells permissive (human embryo fibroblasts (HE)), semipermissive (A549) and nonpermissive (HEp-2) for the virus. Preinfection of the cells with HCMV induced enhanced adhesiveness and invasiveness of bacteria in the permissive HE cells. In the semipermissive A549 cells, where HCMV immediate-early (IE) mRNA transcripts and IE proteins were detected, a significant effect on the initial phase of invasiveness, the adherence phase, was demonstrated. HCMV had no effect on invasiveness of S. typhimurium in nonpermissive HEp-2 cells. Neither HCMV IE transcripts nor IE proteins could be detected in these cells.

Antigens, Surface↗