Biomedical subjects

M R Visser

Publications and source records attributed to M R Visser.

At least 37 records · Page 2Linked to original sources

PubMed1999

[Intra-osseus gas formation in osteomyelitis of vertebrae and pelvis by Klebsiella pneumoniae].

A 59-year-old woman had persistent sepsis after abdominal operations because of a volvulus and subsequently a retroperitoneal abscess, in spite of antibiotic treatment against Klebsiella pneumoniae, which grew in blood cultures. During abscess drainage, a haemorrhage from the infrarenal part of the aorta had occurred; in view of a presumed aortitis this part had been replaced by a bifemoral bypass. Computer tomography revealed intraosseous formation of gas in vertebrae and pelvis. At operation, abscesses were drained and necrotomy and sequestrotomy of the bone were performed. Cultures of the pus from the iliac crests showed K. pneumoniae. The antibiotic management was changed; the wounds were flushed regularly. After exposure of the wounds still draining after 6 months and vascular surgery because of occlusion of the bypass after 7 months, the patient recovered well. She died 2 years later from a cerebral haemorrhage.

Abscess↗

PubMed1999

The effects of ABT-229 and octreotide on interdigestive small bowel motility, bacterial overgrowth and bacterial translocation in rats.

BACKGROUND: Interdigestive small bowel motility has a regulatory function on the microflora of the upper small bowel. Here we investigate the effects of ABT-229 and octreotide on morphine-induced dysmotility, the accompanying bacterial overgrowth and bacterial translocation. METHODS: Rats were fitted with jejunal myoelectrodes and a subcutaneous cannula for continuous infusion of saline or morphine. Fasting motility was measured for 6 h on four occasions: one control measurement (day 0) and three measurements on consecutive days (days 1-3) while receiving saline alone (group A), morphine alone (group B), saline + ABT-229 (group C), morphine + ABT-229 (group D), saline + octreotide (group E) or morphine + octreotide (group F). Samples from the mesenteric lymph node complex (MLN), liver, spleen, duodenum and ileum were taken for quantitative microbial culturing on day 4. RESULTS: Neither ABT-229 nor octreotide increased the number of propagated activity fronts during saline infusion. During morphine-induced dysmotility, ABT-229 induced more propagated activity fronts in group D (13.4, 9.8 and 8.8 per 6 h) than in group B (7.0, 4.5, 3.8 per 6 h) on days 1, 2 and 3 (P < 0.05 for all days) Octreotide did not induce more propagated activity fronts. Disruption of small bowel motility by morphine led to bacterial overgrowth in the duodenum. ABT-229 and octreotide did not reduce the bacterial growth levels. The total incidence of bacterial translocation was significantly higher in the morphine-treated animals than in the saline-treated animals. Neither ABT-229 nor octreotide reduced the bacterial translocation incidence. The number of propagated activity fronts on day 3 and duodenal bacterial growth correlated significantly in groups A, E and F. CONCLUSIONS: ABT-229, but not octreotide, reduced morphine induced dysmotility. Small bowel bacterial overgrowth and bacterial translocation were not prevented. Fasting small bowel motility has a regulatory function on the intestinal microflora of the upper small bowel.

Animals↗

PubMed1999

Comparative activities of clinafloxacin, grepafloxacin, levofloxacin, moxifloxacin, ofloxacin, sparfloxacin, and trovafloxacin and nonquinolones linozelid, quinupristin-dalfopristin, gentamicin, and vancomycin against clinical isolates of ciprofloxacin-resistant and -susceptible Staphylococcus aureus strains.

The activities of eight fluoroquinolones and linezolid, quinupristin-dalfopristin (Synercid), gentamicin, and vancomycin were tested against 96 ciprofloxacin-susceptible and 205 ciprofloxacin-resistant Staphylococcus aureus strains. Overall, clinafloxacin, followed by moxifloxacin and trovafloxacin, was the most active quinolone tested. For all isolates, linezolid and quinupristin-dalfopristin showed activities that were at least comparable to vancomycin, with no cross-resistance to any other test compound.

Anti-Bacterial Agents↗

PubMed1999

Revealing response shift in longitudinal research on fatigue--the use of the thentest approach.

In this study we examined whether response shift resulting from changes in internal standards occurs in cancer patients undergoing radiotherapy. Ninety-nine newly diagnosed patients undergoing radiotherapy were administered two standardized self-report measures of fatigue prior to receiving radiotherapy. After completion of radiotherapy, patients filled out these questionnaires as a conventional posttest and in reference to how they perceived themselves as they were prior to radiotherapy (a so-called 'thentest'). A transition (direct change) score on fatigue was used as a stratification measure. Patients were subsequently interviewed about their responses. The pattern of mean scores indicative of response-shift effects was found in two distinct subgroups: patients experiencing diminishing levels of fatigue and patients facing early stages of adaptation to increased levels of fatigue. Since response shift may adversely affect the results of self-reported outcomes in clinical trials or other longitudinal research, further research is very much needed.

Adaptation, Psychological↗

PubMed1998

Fatigue, depression and quality of life in cancer patients: how are they related?

In a study concerning a group of cancer patients undergoing radiotherapy three research questions were addressed. (1) Is fatigue a valid criterion for depression in these somatically ill patients? (2) What is the 'cause-and-effect' relation between fatigue and depression? (3) To what extent are fatigue and depression related to patients' quality of life. A heterogeneous sample of cancer patients (n = 250) were interviewed before treatment, 2 weeks after treatment and 9 months later. Fatigue was measured using the MFI, a self-report instrument covering five dimensions of fatigue. Depression was assessed with the non-somatic items of the CES-D. Quality of life had to be indicated on a Cantrill ladder. Fatigue and depression do not follow the same course over time. Just after radiotherapy, fatigue had either increased or remained stable, depending on the dimension under consideration. Depression, in contrast, decreased. Nine months later fatigue had decreased, whereas levels of depression remained stable. Concurrent relations between fatigue and depression were mostly moderate. There was no strong evidence for a cause-and-effect relationship between depression and fatigue. Depression showed highest concurrent relationships with quality of life, especially before treatment. Prospectively, depression and the dimension of physical fatigue were the main predictors for quality of life. Fatigue is not a valid criterion for depression in these patients. Nor is there a strong cause-and-effect relationship. Both depression and physical fatigue are relevant to patients' quality of life.

Adolescent↗

PubMed1998

Understanding the level of fatigue in cancer patients undergoing radiotherapy.

This study tests the hypothesis that a discrepancy between resources and demands explains most of the variance in fatigue in cancer patients undergoing radiotherapy. Patients (n=250) were interviewed at pretreatment, posttreatment, and at 9-month follow-up. Resources involved physical condition, neuroticism, optimism, social support, gender, age, and level of education. Demands entailed prognosis, radiotherapy dose, the effort associated with actual activity, and the patient's perception of overall burden. Regression analyses were performed, using interaction terms to operationalize the discrepancy between resources and demands. The hypothesis was not supported. At pretreatment, physical condition explained most of the fatigue, whereas, at posttreatment, both the patients' physical condition and perception of burden contributed to fatigue. At follow-up, demands did not add to the variance already explained by resources, and vice versa. Factors that contribute to the patient's physical condition before starting radiotherapy and to his/her perception of burden need to be addressed to further our understanding of their fatigue.

Adolescent↗

PubMed1998

Fulminant acute pancreatitis and infected necrosis: results of open management of the abdomen and "planned" reoperations.

BACKGROUND: Controversy still surrounds the management of fulminant acute necrotizing pancreatitis. Because mortality rates continue to be high, especially in patients with fulminant acute pancreatitis and infected necrosis, aggressive surgical techniques, such as open management of the abdomen and "planned" reoperations, seem to be justified. STUDY DESIGN: From 1988 through 1995, 28 patients with fulminant acute pancreatitis and infected necrosis were treated with open management of the abdomen followed by planned reoperations at our surgical intensive care unit. RESULTS: All patients had infected necrosis with severe clinical deterioration: 12 patients had an Acute Physiology and Chronic Health Evaluation (APACHE) II score > or = 20 and 16 patients had a Simplified Acute Physiology Score (SAPS) > or = 15. Nineteen patients suffered from severe multiorgan failure; the remaining 9 patients needed only ventilatory and inotropic support. The mean number of reoperations was 17. In 14 patients, major bleeding occurred; fistula developed in 7. Later, 9 abscesses were drained percutaneously. The hospital mortality rate was 39%. Longterm morbidity in survivors was substantial, especially concerning abdominal-wall defects. CONCLUSIONS: Open management of the abdomen followed by planned reoperations is an aggressive but reasonably successful surgical treatment strategy for patients with fulminant acute pancreatitis and infected necrosis. Morbidity and mortality rates were high, but in these critically ill patients, such high rates could be expected. Because management and clinical surveillance require specific expertise, management of these patients is best undertaken in specialized centers.

APACHE↗

PubMed1998

Fatigue and radiotherapy: (A) experience in patients undergoing treatment.

Cancer patients undergoing radiotherapy frequently report fatigue. However, knowledge of the importance of fatigue for these patients and of the factors associated with their fatigue is limited. The aim of the current investigation was to gain more insight into fatigue as related to radiotherapy by answering the following questions. First, how is the experience of fatigue best described? Secondly, to what extent is fatigue related to sociodemographic, medical (including treatment), physical and psychological factors? Finally, is it possible to predict which patients will suffer from fatigue after completion of radiotherapy? Patients with different types of cancer receiving radiotherapy with curative intent (n = 250) were interviewed before and within 2 weeks of completion of radiotherapy. During treatment, patients rated their fatigue at 2-weekly intervals. Results indicate a gradual increase in fatigue over the period of radiotherapy and a decrease after completion of treatment. Fatigue scores obtained after radiotherapy were only slightly, although significantly, higher than pretreatment scores. After treatment, 46% of the patients reported fatigue among the three symptoms that caused them most distress. Significant associations were found between post-treatment fatigue and diagnosis, physical distress, functional disability, quality of sleep, psychological distress and depression. No association was found between fatigue and treatment or personality characteristics. Multivariate regression analysis demonstrated that the intensity of pretreatment fatigue was the best predictor of fatigue after treatment. In view of this finding, a regression analysis was performed to gain more insight into the variables predicting pretreatment fatigue. The degree of functional disability and impaired quality of sleep were found to explain 38% of the variance in fatigue before starting radiotherapy. Fatigue in disease-free patients 9 months after treatment is described in paper (B) in this issue.

Fatigue↗

PubMed1998

Fatigue and radiotherapy: (B) experience in patients 9 months following treatment.

Little is known regarding the prevalence and course of fatigue in cancer patients after treatment has ended and no recurrence found. The present study examines fatigue in disease-free cancer patients after being treated with radiotherapy (n = 154). The following questions are addressed. First, how do patients describe their fatigue 9 months after radiotherapy and is this different from fatigue in a nonselective sample from the general population (n = 139)? Secondly, to what degree is fatigue in patients associated with sociodemographic, medical, physical and psychological factors? Finally, is it possible to predict which patients will suffer from fatigue 9 months after radiotherapy? Results indicated that fatigue in disease-free cancer patients did not differ significantly from fatigue in the general population. However, for 34% of the patients, fatigue following treatment was worse than anticipated, 39% listed fatigue as one of the three symptoms causing them most distress, 26% of patients worried about their fatigue and patients' overall quality of life was negatively related to fatigue (r = -0.46). Fatigue in disease-free patients was significantly associated with: gender, physical distress, pain rating, sleep quality, functional disability, psychological distress and depression, but not with medical (diagnosis, prognosis, co-morbidity) or treatment-related (target area, total radiation dose, fractionation) variables. The degree of fatigue, functional disability and pain before radiotherapy were the best predictors of fatigue at 9-month follow-up, explaining 30%, 3% and 4% of the variance respectively. These findings are in line with the associations found with fatigue during treatment as reported in the preceding paper in this issue. The significant associations between fatigue and both psychological and physical variables demonstrate the complex aetiology of this symptom in patients and point out the necessity of a multidisciplinary approach for its treatment.

Aged↗

PubMed1998

Monocytes modulate enhancement of HIV-1 replication by Mycobacterium tuberculosis.

To investigate the effects of Mycobacterium tuberculosis on HIV-1 replication, peripheral blood mononuclear cells (PBMC) of bacille Calmette-Guerin (BCG)-vaccinated donors and non-BCG-vaccinated donors were infected in vitro with a lymphotropic isolate of HIV-1 and cultured in the presence of purified protein derivative (PPD). Addition of PPD resulted in enhanced HIV-1 replication and lymphoproliferation in BCG-vaccinated donor PBMC, while PPD had no such effects in control PBMC. HIV-1 replication increased even more when monocytes were removed from PBMC, while lymphoproliferation was decreased. High percentages of monocytes were associated with a decreased HIV-1 replication and proliferation that could not be reversed by addition of antibodies against the cytokines IL-1, transforming growth factor-beta (TGF-beta) or indomethacin. PPD stimulates PBMC to release IL-10, a cytokine known to down-regulate proliferation and HIV-1 replication. PPD-induced effects on proliferation as well as HIV-1 replication could be partially blocked by adding a monoclonal antibody against MHC class II molecules, suggesting that part of the mechanism of PPD-induced enhancement is T memory cell activation.

Antibodies, Monoclonal↗

PubMed1998

Predictors of recurrence of fulminant bacterial peritonitis after discontinuation of antibiotics in open management of the abdomen.

OBJECTIVE: To assess a scoring system for predicting recurrence of fulminant bacterial peritonitis after discontinuation of antimicrobial treatment in patients being treated by open management of the abdomen for persistent bacterial peritonitis after perforation of the digestive tract, anastomotic disruption, or necrotising pancreatitis. DESIGN: Retrospective study. SETTING: University Hospital, The Netherlands. SUBJECTS: 58 consecutive patients. MAIN OUTCOME MEASUREMENTS: Recurrence of fulminant bacterial peritonitis and survival. RESULTS: 13 of the 58 patients (22%) died during the initial course of antimicrobial drugs. 14 of the remaining 45 patients had a recurrence of fulminant bacterial peritonitis after discontinuation of antimicrobial drugs, 4 of whom died. Predictive criteria included raised white cell count (WCC) (p = 0.02), duration of initial antibiotic treatment (p = 0.05), and deterioration in Simplified Acute Physiology Score (p = 0.05). Using the WCC and the duration of initial antimicrobial treatment together with other variables that showed a predictive trend (body temperature, percentage band cells, underlying disease, and use of inotropic agents), in a new scoring system (0-12), fulminant bacterial peritonitis did not recur when the score was 0-3, but in 9 of 11 patients with a score of 6 or more it did (p < 0.001). CONCLUSION: Patients at increased risk of recurrence of fulminant bacterial peritonitis during open management of the abdomen can be identified at the time of discontinuation of antimicrobial treatment by a new scoring system; antimicrobial treatment should not be discontinued in patients with a score of 6 or more.

Adult↗

PubMed1998

Activation and cell cycle antigens in CD4+ and CD8+ T cells correlate with plasma human immunodeficiency virus (HIV-1) RNA level in HIV-1 infection.

The relationship between T cell activation and human immunodeficiency virus type 1 (HIV-1) replication was studied in HIV-infected subjects, 20 with and 10 without anti-HIV treatment. Expression of Ki-67 proliferation-associated antigen was increased in CD4+ and CD8+ T cells and correlated with HLA-DR. In subjects without anti-HIV treatment, the plasma HIV-1 RNA level correlated with HLA-DR in CD4+ T cells, with Ki-67 in CD8+ T cells, and with expression of CD38 in both T cell subsets. A proportion of treated subjects had increased T cell activation despite 4 months of highly active antiretroviral treatment (HAART). In subjects receiving HAART, a high percentage of HLA-DR+ CD4+ T cells was associated with signs of opportunistic infections. This work supports the concept that, in the natural course of HIV-1 infection, HIV replication itself leads to general T cell activation and that opportunistic infections generate additional CD4+ T cell activation and HIV replication.

ADP-ribosyl Cyclase↗

PubMed1998

The role of interdigestive small bowel motility in the regulation of gut microflora, bacterial overgrowth, and bacterial translocation in rats.

OBJECTIVE: To clarify the role of the migrating motor complex (MMC) in the regulation of small intestinal microflora and bacterial translocation. SUMMARY BACKGROUND DATA: The intestinal microflora may serve as a source of infectious microorganisms. Failure of regulatory mechanisms of the intestinal flora could therefore play an important role in the pathogenesis of gut-derived infections. METHODS: Rats were fitted with small intestinal myoelectrodes. MMCs were measured on a control day and 3 consecutive days during continuous administration of morphine or placebo. Mesenteric lymph nodes, liver, spleen, peripheral blood, duodenum, and ileum samples were cultured quantitatively. RESULTS: The mean MMC cycle length in placebo-treated animals was 15.1+/-0.5 minutes. MMCs were completely disrupted after morphine treatment. Total bacterial growth in the duodenum was 7.27+/-0.34 10log colony-forming units (CFU)/g with placebo and 8.28+/-0.27 CFU/g with morphine. In placebo-treated animals, the mean MMC cycle length the day before culturing correlated with total bacterial growth in the duodenum. Translocation incidences to the mesenteric lymph nodes, liver, spleen, and blood were 0/8, 1/8, 0/8, and 0/8 with placebo and 7/8, 6/8, 5/8, and 0/8 with morphine. The overall translocation incidence was 1/8 in placebo-treated animals and 8/8 in morphine-treated animals. CONCLUSIONS: The MMC is an important mechanism controlling bacterial growth in the upper small bowel. Its disruption with morphine promotes duodenal bacterial overgrowth and bacterial translocation.

Animals↗

PubMed1998

Fatigue in primary Sjögren's syndrome.

OBJECTIVE: To assess fatigue in relation to depression, blood pressure, and plasma catecholamines in patients with primary Sjögren's syndrome (SS), in comparison with healthy controls and patients with rheumatoid arthritis. METHODS: For the assessment of fatigue the Multidimensional Fatigue Inventory (MFI) was used, a 20 item questionnaire, covering the following dimensions: general fatigue, physical fatigue, mental fatigue, reduced motivation, and reduced activity. Furthermore, the Zung depression scale was used to quantify aspects of depression. Forty nine female primary SS patients, 44 female patients with rheumatoid arthritis (RA), and 32 healthy women filled in both questionnaires. In addition, supine values of blood pressure and plasma catecholamines were measured in the patients with primary SS. RESULTS: Primary SS patients were more fatigued compared with the healthy controls on all the five dimensions of the MFI. When the analyses were repeated using depression as a covariate, group differences disappeared for the dimensions of reduced motivation and mental fatigue. In the primary SS patients, significant positive correlations between depression and the dimensions of reduced motivation and mental fatigue were found. Comparing patients with primary SS with those with RA, using depression as covariate, no statistically significant differences were found between these groups. No relation between fatigue and blood pressure was found, but a negative correlation was observed between the general fatigue subscale of the MFI and plasma noradrenaline. CONCLUSION: Patients with primary SS report more fatigue than healthy controls on all the dimensions of the MFI and when controlling for depression significant differences remain on the dimensions of general fatigue, physical fatigue, and reduced activity. The negative correlations between levels of noradrenaline and general fatigue in patients with primary SS may imply the involvement of the autonomic nervous system in chronic fatigue.

Adult↗

PubMed1997

[Anglo-Saxon guidelines for the treatment of community-acquired pneumonia applicable in The Netherlands as well].

There are three Anglo-Saxon guidelines for the management of patients with a community-acquired pneumonia: an American, a British and a Canadian one. The guidelines correspond fairly well. There is a subdivision into categories according to whether the patients are treated at home (formerly healthy patients younger than 60 years versus patients with pre-existent disease or aged 60 years and more) or in the hospital (patients not needing intensive care versus those who do need it). For each category the most common causative micro-organisms are listed together with recommended antibiotic treatment. The Canadian guidelines have nursing home patients as a separate category because of slightly different causative organisms due to frequent microaspiration. The guidelines are applicable to the situation in the Netherlands, with a few exceptions: antibiotic resistance is not a major problem in the Netherlands (as yet), and contrary to what the guidelines state an agent with activity against Pseudomonas aeruginosa is not necessary; the same agents as in category III can be prescribed in these patients. A macrolide or azalide antibiotic is advisable for intensive care patients in view of the possibility of infection with Legionella pneumophila or Mycoplasma pneumoniae.

Adult↗

PubMed1997

N-acetyl-L-cysteine-induced up-regulation of HIV-1 gene expression in monocyte-derived macrophages correlates with increased NF-kappaB DNA binding activity.

Nuclear factor kappaB (NF-kappaB) is an important cellular regulator of human immunodeficiency virus (HIV) gene expression. In T cells, N-acetyl-L-cysteine (NAC) inhibits the induction of NF-kappaB and transcription of HIV-1. However, NAC up-regulates HIV-1 replication in monocyte-derived macrophages (MDM). In this study we demonstrate that NAC treatment of MDM transfected with a chloramphenicol acetyltransferase (CAT) construct under transcriptional control of the HIV-1 long terminal repeat resulted in an up-regulation of CAT activity. Furthermore, MDM transfected with a HIV-1-NF-kappaB-CAT construct also produced increased CAT activity after NAC treatment. In addition, electrophoretic mobility shift assays revealed that nuclei of NAC-treated MDM contained increased binding activity to wild-type, but not mutant, kappaB oligonucleotides. Components of the binding activity were identified with antibodies as the NF-kappaB subunits p50 and p65. These data indicate that NAC-induced enhancement of HIV-1 replication in MDM is regulated at the level of viral gene expression and mediated by NF-kappaB.

Acetylcysteine↗

PubMed1997

Mannoproteins of Cryptococcus neoformans induce proliferative response in human peripheral blood mononuclear cells (PBMC) and enhance HIV-1 replication.

To investigate the possible role of Cryptococcus neoformans var. neoformans in HIV disease progression, and to identify the responsible cryptococcal components, an in vitro cell culture model was set up to study the C. neoformans-induced enhancement of HIV replication in HIV-1-infected PBMC. Similar to whole C. neoformans, cell-wall membrane fraction and mannoproteins induced proliferation of PBMC and enhancement of lymphotropic HIV replication in HIV-infected PBMC, while galactoxylomannan did not. MoAbs capable of interfering with MHC class II-mediated antigen presentation prevented the induction of cell proliferation by whole C. neoformans or cryptococcal mannoproteins. MoAb binding to adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) also inhibited C. neoformans-induced cell proliferation. In addition, anti-MHC class II MoAb inhibited the enhancement of HIV replication by C. neoformans. The results suggest that: (i) C. neoformans may accelerate HIV disease progression by stimulation of HIV replication through MHC class II-mediated antigen presentation; and (ii) cryptococcal mannoprotein may be one of the responsible components. The ability to enhance HIV replication in PBMC in vitro is not unique for C. neoformans. However, this is the first report to study in detail a yeast-induced enhancement of HIV replication in PBMC.

Antibodies, Monoclonal↗

PubMed1994

Role for oxygen radicals in self-sustained HIV-1 replication in monocyte-derived macrophages: enhanced HIV-1 replication by N-acetyl-L-cysteine.

N-acetyl-L-cysteine (NAC) has been proposed as a therapeutic agent for AIDS patients because it reduces human immunodeficiency virus type 1 (HIV-1) replication in stimulated T cells. However, NAC and glutathione enhanced acute HIV-1 replication in monocyte-derived macrophages. Buthionine sulfoximine did not affect NAC-mediated enhanced HIV-1 replication, indicating that the NAC-mediated effects are glutathione-independent. Superoxide dismutase and the hydroxyl radical scavengers dimethylthiourea and thiourea, but not urea, inhibited acute HIV-1 replication in macrophages. NAC reduced ferricytochrome c and increased dose-dependently Fe(III)-citrate and Fe(III)-EDTA-catalyzed hydroxyl radical formation in a system using glucose and glucose oxidase. Dimethylthiourea and thiourea, but not urea and superoxide dismutase, dose-dependently inhibited NAC-mediated enhancement of HIV-1 replication. These data suggest that oxygen radicals play an important role in self-sustained HIV-1 replication in macrophages and that oxygen radical scavengers other than NAC should be considered as therapeutic agents for AIDS patients.

Acetylcysteine↗