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Biomedical subjects

C Verhagen

Publications and source records attributed to C Verhagen.

At least 19 recordsLinked to original sources
PubMed2002

Fatigue in cancer patients during and after treatment: prevalence, correlates and interventions.

Research on the relationship between cancer and fatigue has increased considerably in recent years. In this review, we focus on fatigue observed in patients during and after treatment for cancer, using data from empirical studies. The results from these studies indicate that fatigue is mostly studied during active treatment for cancer, and is an important problem during this period. Studies that focused on fatigue in disease-free cancer patients, although less prominent, also indicate fatigue is an important complaint in this time period. It is hard to draw conclusions with regard to the relationships between fatigue and disease- and treatment-related characteristics, because these relationships are seldom properly investigated. Relationships between fatigue and psychological, social, behavioural and physical factors have been established in several studies. However, most studies focused on the depression-fatigue association. Finally, most intervention studies to reduce fatigue appear to be successful, but the follow-up analyses are lacking.

Adolescent↗
PubMed2000

Follow-up regimen of differentiated thyroid carcinoma in thyroidectomized patients after thyroid hormone withdrawal.

UNLABELLED: For differentiated, nonmedullary thyroid carcinoma, postsurgical ablation of thyroid remnants and treatment of residual tumor and metastases with 131I is a potentially curative therapy. The aim of this study was to optimize the diagnostic protocol for the follow-up of thyroidectomized patients. METHODS: Two hundred fifty-four patients (187 females, 67 males; mean age, 45 y; range, 8-83 y) were studied retrospectively for a mean follow-up period of 2.7 y (range, 1-12.5 y). An evaluation study consisted of a low-dose 131I diagnostic procedure under hyperthyroid conditions (thyroid-stimulating hormone > 30 MicroU/mL), 201TI scintigraphy, and measurement of thyroglobulin (Tg) under hypothyroid conditions. A total of 254 preablation studies (1 study per patient) and 586 follow-up studies (average number of studies, 2.3 per patient) were evaluated. RESULTS: Before ablation, low-dose 131I screening was useful to estimate the size of the thyroid remnant. Low Tg levels (<10 pmol/L) indicated the absence of metastases. After ablation, undetectable Tg levels indicated the absence of tumor recurrence. When Tg levels were high (>10 pmol/L), local recurrence or metastases were always observed, providing the basis for additional high-dose 131I therapy. In these patients, 201TI imaging did not provide a significant contribution to patient management. In the case of autoantibodies against Tg, both low-dose 131I screening and 201TI scintigraphy may be advocated to allow an aggressive diagnostic work-up. CONCLUSION: Tg plays a key role in follow-up and in making decisions to treat patients with differentiated thyroid carcinoma. The role of 201TI imaging is very limited. In patients with negative low-dose 131I screening, 201TI scintigraphy can be considered when Tg is elevated or cannot be evaluated because of autoantibodies against Tg. Under such circumstances, administration of a therapeutic 131I dose without 201TI imaging can be considered.

Adenocarcinoma, Follicular↗
PubMed1999

Immunohistological analysis of in situ expression of mycobacterial antigens in skin lesions of leprosy patients across the histopathological spectrum. Association of Mycobacterial lipoarabinomannan (LAM) and Mycobacterium leprae phenolic glycolipid-I (PGL-I) with leprosy reactions.

The presence of mycobacterial antigens in leprosy skin lesions was studied by immunohistological methods using monoclonal antibodies (MAbs) to Mycobacterium leprae-specific phenolic glycolipid I (PGL-I) and to cross-reactive mycobacterial antigens of 36 kd, 65 kd, and lipoarabinomannan (LAM). The staining patterns with MAb to 36 kd and 65 kd were heterogeneous and were also seen in the lesions of other skin diseases. The in situ staining of PGL-I and LAM was seen only in leprosy. Both antigens were abundantly present in infiltrating macrophages in the lesions of untreated multibacillary (MB) patients, whereas only PGL-I was occasionally seen in scattered macrophages in untreated paucibacillary lesions. During treatment, clearance of PGL-I from granulomas in MB lesions occurred before that of LAM, although the former persisted in scattered macrophages in some treated patients. This persistence of PGL-I in the lesions paralleled high serum anti-PGL-I antibody titers but was not indicative for the presence of viable bacilli in the lesions. Interestingly, we also observed a differential expression pattern of PGL-I and LAM in the lesions of MB patients with reactions during the course of the disease as compared with those without reactions. In conclusion, the in situ expression pattern of PGL-I and LAM in MB patients may assist in early diagnosis of reactions versus relapse.

Antibodies, Bacterial↗
PubMed1999

Experimental autoimmune keratitis induced in rats by anti-cornea T-cell lines.

PURPOSE: Idiopathic inflammation of the cornea, keratitis, has been proposed to result from an autoimmune process, but thus far no convenient animal model of keratitis exists. An attempt was made to establish an animal model for keratitis, to investigate possible autoimmune mechanisms. METHODS: T-cell lines were established from lymph node cells removed from rats immunized with bovine corneal epithelium (BCE) extract. After restimulation in vitro with BCE or a specific corneal antigen, the cells were transferred by intraperitoneal injection into naive rats, rats subjected to total body irradiation, or rats in which only one eye was irradiated. RESULTS: Neither direct immunization with corneal antigens nor transfer of activated anti-corneal T-cells into naive rats gave any signs of keratitis. Irradiation alone did not induce corneal inflammation. Transfer of corneal-specific activated T cells into irradiated rats produced keratitis starting around day 4 and culminating around day 8. The disease was self-limiting and the severity dependent on the dose and site of radiation. Keratitis was characterized by corneal haze, conjunctival and episcleral hyperemia, episcleral hemorrhages, chemosis, corneal infiltrates, and vascularization. Immunohistochemistry showed T-cell and macrophage infiltration of epithelium and stroma in the affected corneas. CONCLUSIONS: Thus, keratitis may be produced by T cells reactive to corneal antigens, provided that the target tissue has been made susceptible by irradiation. The effectiveness of T-cell vaccination in preventing adoptive keratitis suggests that systemic as well as local tissue factors may regulate the disease process.

Adoptive Transfer↗
PubMed1999

Management of occupational exposures to bloodborne viruses: HIV post-exposure prophylaxis.

Unlike exposure to hepatitis B-infected blood, where risk of transmission is low and post-exposure prophylaxis is safe and effective, exposure to HIV is much different. This risk of HIV transmission is extremely low and the safety and efficacy of chemoprophylaxis is uncertain. Dental health care workers should be made aware that the potential side effects and toxicity of the standard post-exposure drug regimen outweigh the negligible risk of transmission posed by the exposure.

Anti-HIV Agents↗
PubMed1997

Influx of immunoglobulins from the vascular compartment into a grafted cornea.

PURPOSE: To determine the effect of a fresh corneal wound or a healed corneal scar on the immunodiffusion of immunoglobulins into the cornea. METHODS: F344 rats were immunized with human serum albumin (HSA) 1 week before an autologous rotational keratoplasty of the right cornea or 1 year after an autograft was performed. One group of rats also was treated with gentamicin-dexamethasone ointment in the grafted eye for 1 week after transplantation to reduce the postsurgical inflammatory signs. A serum sample was drawn every week and booster injections with HSA were given after 2 and 3 weeks. At various times after immunization, groups of rats were killed, blood and aqueous humor samples were taken, and the corneas of both eyes were removed. The corneas were divided into the graft or a 3-mm central button and the peripheral rim and weighed. The anti-HSA titer was determined in serum, aqueous humor, and both parts of the corneas. RESULTS: Up to 5 weeks after transplantation, the grafted cornea contained more anti-HSA immunoglobulins than did the control eye. One year postgrafting, no difference was seen. In the first weeks after keratoplasty, influx of anti-HSA from the peripheral into the central cornea was, however, neither obstructed nor enhanced. CONCLUSIONS: Surgical trauma in itself causes increased influx of anti-HSA immunoglobulins into the cornea. Within the cornea, a wound or a scar does not appear to be a barrier for centripetal immunoglobulin diffusion.

Animals↗
PubMed1996

Serologic and polymerase chain reaction analysis of intraocular fluids in the diagnosis of infectious uveitis.

PURPOSE: Infectious uveitis entities are usually rapidly progressive blinding diseases that can be prevented by prompt administration of specific antimicrobial therapy. With the aim of improving early diagnosis in patients with infectious uveitis, intraocular fluid samples from patients with sight-threatening posterior uveitis were investigated to determine the causative agent. METHODS: Thirty-eight patients with acquired immunodeficiency syndrome (AIDS) and retinitis, eight immunosuppressed patients with retinitis, 16 immunocompetent patients with acute retinal necrosis, and 22 immunocompetent patients with toxoplasmic retinochoroiditis were analyzed by polymerase chain reaction for the presence of herpesviruses and Toxoplasma gondii DNA and for local antibody production against these microorganisms. RESULTS: In patients with AIDS and retinitis, polymerase chain reaction was positive for cytomegalovirus DNA in 21 (91%) of the 23 ocular fluid samples obtained during active cytomegalovirus retinitis, whereas local antibody production analysis was negative in all cases. In acute retinal necrosis, varicella-zoster virus or herpes simplex virus could be established as the inciting agent in 81% of the cases, using the combination of both techniques. Polymerase chain reaction was positive in all samples obtained within two weeks after the onset of disease. Toxoplasma gondii DNA was detected in 4 of 13 samples (31%) from immuno-competent patients with active toxoplasmic retinochoroiditis; in each case, local antibody production was also detected. In contrast, no local antibody production was observed in two of three samples from transplant recipients that were positive for T. gondii DNA. All the control samples tested were negative for the above-mentioned tests. CONCLUSIONS: In patients with AIDS, polymerase chain reaction analysis is preferable above local antibody production in detecting the inciting agent of retinitis. In other cases, the combination of both techniques can make a valuable contribution to the diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed1995

Systemic anti-tumor necrosis factor antibody treatment exacerbates endotoxin-induced uveitis in the rat.

Tumor necrosis factor is released in the circulation and aqueous humor during endotoxin-induced uveitis, and induces acute uveitis when injected intraocularly in rats. To elucidate the role of tumor necrosis factor in the development of endotoxin-induced uveitis we analysed the effect of neutralizing anti-tumor necrosis factor antibodies and of pentoxifylline, a drug that inhibits tumor necrosis factor synthesis. Lewis rats were treated with: (a) a single intracardial injection of polyclonal rabbit anti-murine tumor necrosis factor antiserum prior to foot pad injection of 200 micrograms lipopolysaccharide; (b) an intraperitoneal injection of 10 mg pentoxifylline 1 hr before, at the time of, and 3 hr after foot pad injection of lipopolysaccharide; or (c) an intravitreal injection of 20 to 500 micrograms pentoxifylline together with 1 microgram lipopolysaccharide. The ocular inflammation was examined by slit-lamp and evaluated for the presence of hyperemia, flare, miosis, infiltrating cells or hypopyon. Levels of tumor necrosis factor in serum and aqueous samples were determined using a bioassay. Systemic treatment with either anti-tumor necrosis factor antibodies or pentoxifylline resulted in a significant inhibition, 90 and 70% respectively, of serum tumor necrosis factor activity at 3 to 4 hr after lipopolysaccharide injection. Systemic pentoxifylline treatment had no influence on the severity of uveitis. Anti-tumor necrosis factor antibody treatment, in contrast, caused an exacerbation of endotoxin-induced uveitis at t = 20 hr; mean uveitis score 3.9 vs. 1.4 in controls; P < 0.01. Intraocular administration of pentoxifylline together with lipopolysaccharide also had an aggravating effect on uveitis, that was associated with increased levels of intraocular tumor necrosis factor. The results show that inhibition of serum tumor necrosis factor activity does not block the development of endotoxin-induced uveitis. In fact, anti-tumor necrosis factor antibody treatment exacerbates the intraocular inflammation. These findings suggest that tumor necrosis factor may have other than proinflammatory properties in this uveitis model.

Animals↗
PubMed1995

Tumour necrosis factor-induced uveitis in the Lewis rat is associated with intraocular interleukin 6 production.

Lewis rats were injected with recombinant murine tumour necrosis factor-alpha either intravitreally (0.08-50 ng) or intracardially (1 microgram). The intraocular inflammatory response induced by tumour necrosis factor was examined by slit-lamp and protein extravasation into aqueous humor was determined. The phenotype of the inflammatory cells in the eye was analysed by immunohistochemistry. In addition, the kinetics of intraocular interleukin 6 production were determined. At 24 hr after intravitreal injection, a significant clinical uveitis was observed only in rats injected with 50 ng of tumour necrosis factor, when compared to saline-treated controls (P < 0.05). Maximal clinical uveitis and blood-aqueous barrier breakdown were already present at 4 hr after tumour necrosis factor injection. The uveitis was characterized by a massive cellular infiltrate in the anterior segment, consisting predominantly of polymorphonuclear cells and macrophages/monocytes, and to a lesser extent of T lymphocytes. Intraocular interleukin 6 mRNA expression and elevated levels of interleukin 6 in aqueous humor were detected 1 hr after tumor necrosis factor injection, reached a maximum at 3 to 4 hr after injection, and had declined again at 2 hr. Although intracardial injection of 1 microgram of tumour necrosis factor in Lewis rats induced a rise of circulating interleukin 6, it did not produce uveitis. The results obtained with intravitreally injected tumour necrosis factor indicate that intraocular TNF may play a pivotal role in the induction of uveitis in the rat. The transient intraocular production of interleukin 6 early during tumour necrosis factor-induced uveitis suggests that this cytokine may participate in the response induced by tumour necrosis factor.

Animals↗
PubMed1995

Spontaneous development of corneal crystalline deposits in MRL/Mp mice.

PURPOSE: The presence of corneal opacities associated with dacryoadenitis and lacrimal gland destruction has led investigators to consider MRL/Mp mice as models for band keratopathy and Sjögren syndrome. In this study, the authors examined the time course of the corneal opacification and investigated whether the opacities were associated with altered serum levels of parathyroid hormone, calcium, and phosphorus, as well as quantitative and qualitative differences in tear production. METHODS: Corneas were analyzed microscopically and tear fluid production was measured by a modified Schirmer test. RESULTS: Corneal lesions were observed as early as the fifth week after birth. The lesions consisted of calcium phosphate and appeared as punctate, crystalline opacities located subeithelially. Lesions were present in 72% (56 of 78) of the MRL/Mp mice, with no significant difference in incidence between MRL/Mp +/+ and MRL/Mp lpr/lpr mice. Corneal calcification was occasionally associated with a self-limiting keratitis and neovascularization. In control mice, corneal opacities were not observed before the animals were 6 months of age. Levels of circulating parathyroid hormone decreased significantly during the first 16 weeks of age in MRL/Mp mice. In addition, MRL/Mp mice of both sexes had a significantly lower tear fluid production as compared to BALB/c mice of the same age. CONCLUSION: Because corneal lesions start to develop in 5-week-old MRL/Mp mice, thereby preceding the clinical signs of systemic autoimmune disease, and may develop in 6-month-old nonautoimmune-prone mice, it is suggested that calcification develops independent of the systemic autoimmune disease and might be restricted to the cornea.

Animals↗
PubMed1994

T cell immunity to myelin basic protein induces anterior uveitis in Lewis rats.

Uveitis of unknown etiology is known to occur in association with various systemic disorders. We now report that anterior uveitis (AU) can be produced by T cell immunity to myelin basic protein (BP) and accompanies experimental autoimmune encephalomyelitis (EAE). EAE with AU was induced in Lewis rats by immunization to BP in CFA or by immunization to various BP peptides including the encephalitogenic 71-90 peptide. Slit-lamp biomicroscopy of BP-immunized Lewis rats revealed AU, characterised by inflammation of the iris, in 73% of the eyes. The onset of AU in actively immunized rats varied between days 12 and 26, often appearing after spontaneous remission of the paralysis, the hallmark of EAE. The course of AU was progressive, affecting more than 50% of the surface of the iris in 16 of 29 diseased eyes. Like the paralysis, the AU was self-limiting: within 2 weeks the disease remitted. In addition, AU could be adoptively transferred to naive and irradiated rats by a T cell clone specific for BP peptide 71-90. The present observations are compatible with the idea that AU may be triggered by BP-reactive T cells. The myelinated nerves present in the iris have been shown to contain BP. However, these peripheral nerves would now appear to be the only peripheral nerves susceptible to acute EAE.

Amino Acid Sequence↗
PubMed1994

Kinetics of intraocular tumor necrosis factor and interleukin-6 in endotoxin-induced uveitis in the rat.

PURPOSE: To determine the kinetics of tumor necrosis factor (TNF) and interleukin-6 (IL-6) in serum and aqueous humor of rats with different susceptibilities to endotoxin-induced uveitis (EIU), after footpad injection of lipopolysaccharide (LPS). METHODS: Samples were collected from EIU-susceptible Lewis rats and EIU-resistant Brown Norway (BN) rats for up to 72 hours after LPS injection. Specific bioassays were used to measure TNF and IL-6 activity. Northern blot analysis was used to assess intraocular IL-6 mRNA expression. RESULTS: High levels of TNF and IL-6 were detected in serum of both rat strains early after LPS injection. A second rise in serum TNF was observed at 18 to 20 hours in Lewis rats only. In aqueous humor of Lewis rats, high levels of TNF and IL-6 were observed early after LPS injection (2 to 8 hours) and concomitant with maximal uveitis (18 to 24 hours). Low levels of TNF and IL-6 were found in aqueous humor of BN rats. Ocular IL-6 mRNA was detected at the same time as IL-6 activity was measured in aqueous humor. CONCLUSIONS: The results of this study indicate that both TNF and IL-6 may play a role in the pathogenesis of EIU. The early release of TNF in aqueous humor during EIU suggests that this cytokine may serve as an initial mediator of intraocular inflammation. Furthermore, Northern blot analysis indicates that IL-6 is produced locally during EIU.

Animals↗
PubMed1994

Human corneal extract enhances serum complement activity.

PURPOSE: The concomitant presence of complement-activation products in the cornea during inflammation is well described. The present study was undertaken to analyze the complement activity of normal human corneal tissue and to assess the presence of complement-modulating activities. METHODS: Human corneal tissue was extracted in veronal-buffered saline. The overall complement (C) activity of the human corneal extract (HCE) and the effect of HCE on serum C-activity were investigated using a hemolytic assay. Anion-exchange chromatography and gel filtration were applied for biochemical analysis of HCE. Monoclonal anti-human C3 was used to detect corneal C3 and to remove C3 from HCE by immunoadsorption. RESULTS: It was found that C-activity of HCE was less than 200 U/g tissue. Experiments to test whether HCE exhibited inhibitory activity led to an unexpected result: When added to human serum dilutions, HCE caused a significant, dose-dependent increase of C-activity. Pretreatment of HCE at 56 degrees C abolished the effect. Analysis of HCE by anion-exchange chromatography revealed two C-enhancing peaks. One peak was identified as C3 whereas the identity of the other protein peak remained unknown. CONCLUSIONS: Results indicate that the human cornea contains an as yet unidentified heat sensitive factor(s) able to enhance complement activity of serum. It is postulated that this factor(s) may play an important role in corneal physiology and pathology.

Chromatography, Gel↗
PubMed1992

Characterization of soluble protein BCP 11/24 from bovine corneal epithelium, different from the principal soluble protein BCP 54.

The water-soluble fraction of bovine corneal epithelium was analysed by polyacrylamide gel electrophoresis in the presence of SDS (SDS-PAGE). Next to the principal soluble protein BCP 54, which has recently been identified as a corneal aldehyde dehydrogenase (ALDH), another abundant protein was observed, which we have denoted BCP 11/24, due to its estimated molecular weight of 11 kDa in SDS-PAGE and 24 kDa in high performance gel filtration under non-denaturing conditions. This protein was isolated and characterized by biochemical and immunochemical techniques. The isolation of BCP 11/24 was initially hampered by its tendency to bind non-covalently to BCP 54. BCP 11/24 behaves identically in reduced and unreduced SDS-PAGE and is probably not a glycoprotein. Isoelectric focusing indicated microheterogeneity of BCP 11/24, yielding bands with isoelectric points of 6.1, 5.9, 5.7 and 5.6. A rabbit antiserum directed against BCP 11/24, that did not recognize BCP 54, demonstrated that the distribution of BCP 11/24 in different ocular tissues as well as its light microscopic localization in corneal epithelium is strikingly similar to that of BCP 54. Together with its tendency to interact with BCP 54 in vitro, this suggests the possibility that BCP 11/24 is associated with BCP 54 in vivo, fulfilling a function which may be related to the activity of BCP 54 as a corneal ALDH. In contrast with BCP 54, however, BCP 11/24 was not detectable in corneal endothelium. The antiserum did not detect any immunologically related molecules in corneal epithelium extracts of sheep, human or rat origin, indicating that BCP 11/24 is probably not as highly conserved as BCP 54.

Aldehyde Dehydrogenase↗