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Biomedical subjects

M Boulton

Publications and source records attributed to M Boulton.

At least 37 records · Page 2Linked to original sources

An evaluation of a cancer counselling service.

The CancerBACUP London Counselling Service offered short-term face-to-face counselling to self-referred cancer patients and their relatives and friends, provided by experienced supervised counsellors working within a humanistic theoretical framework. This study aimed to identify its clients' characteristics, use of the service, extent of perceived benefits and satisfaction with the service. Sociodemographic data were collected in Data Sheets from all 384 clients who booked an appointment over 18 months; they were predominantly female, < 50 years old and from non-manual social classes. Significantly more people in those classes and in the 30-59 age group attended three or more sessions. Three hundred and nine clients who attended at least once were sent an Evaluation Form; 142 responded. The probability of the Evaluation Forms' return was greater for those who had completed more sessions; the great majority of respondents felt that they had benefited, and were satisfied with the service. This study, notwithstanding its limitations, shows that a short course of counselling may be perceived by clients to be helpful; it also raises other issues of value to those involved in cancer services and/or counselling provision.

Adult↗

Centration of donor trephination in human corneal transplantation.

PURPOSE: To develop and evaluate a new method to quantify centration of the trephined donor cornea relative to the limbus. METHODS: After human donor corneas were trephined for penetrating keratoplasty, the remaining corneoscleral discs were stained and subjected to image analysis. The centration of the excised donor cornea relative to the limbus was calculated by measuring their centroids from the "captured" images. RESULTS: Fifty-two corneoscleral discs were analyzed. The average deviation from the centre was 0.32 mm (SD, 0.18 mm). Neither surgeon nor the type of trephine significantly influenced the mean centroid deviation. CONCLUSION: We have developed and evaluated a method to quantify centration of human donor cornea. In a small series, decentration did not correlate significantly with either the surgeon or the trephine.

Cornea↗

Faith, hope, and charity: an in-depth interview study of cancer patients' information needs and information-seeking behavior

OBJECTIVE: To explore why cancer patients do not want or seek information about their condition beyond that volunteered by their physicians at times during their illness. DESIGN: Qualitative study based on in-depth interviews. SETTING: Outpatient oncology clinics at a London cancer center. PARTICIPANTS: 17 patients with cancer diagnosed in previous 6 months. Main outcome measures Analysis of patients' narratives to identify key themes and categories. RESULTS: While all patients wanted basic information on diagnosis and treatment, not all wanted further information at all stages of their illness. Three overarching attitudes to their management of cancer limited patients' desire for and subsequent efforts to obtain further information : faith, hope, and charity. Faith in their doctor's medical expertise precluded the need for patients to seek further information themselves. Hope was essential for patients to carry on with life as normal and could be maintained through silence and avoiding information, especially too detailed or "unsafe" information. Charity to fellow patients, especially those seen as more needy than themselves, was expressed in the recognition that scarce resources-including information and explanations-had to be shared and meant that limited information was accepted as inevitable. CONCLUSIONS: Cancer patients' attitudes to cancer and their strategies for coping with their illness can constrain their wish for information and their efforts to obtain it. In developing recommendations, the government's cancer information strategy should attend to variations in patients' desires for information and the reasons for them.

Journal Article↗

Use and cost of hospital and community service provision for children with HIV infection at an English HIV referral centre.

OBJECTIVE: To describe the use of hospital and community services for children infected with HIV and estimate the cost per patient-year by stage of HIV infection during the era of antiretroviral monotherapy. DESIGN: Data on the use of hospital services were collected from case notes; the use of statutory and nonstatutory community services was recorded through diaries and interviews. Total cost estimates were calculated from unit costs from relevant hospital departments and community organisations. SETTING: Children managed at St. Mary's Hospital (London, England) between 1 January 1986 and 31 December 1994, some of whom used statutory and nonstatutory community services in South East England between 1 November 1994 and 31 May 1996. PATIENTS AND PARTICIPANTS: 118 children with positive HIV antibody status. MAIN OUTCOME MEASURES AND RESULTS: Mean inpatient days, outpatient visits, tests and procedures performed, drugs prescribed, community services used, associated unit costs and average cost estimates per patient-year by stage of HIV infection (1995/1996 values), and lifetime costs. Service provision during the study period was predominantly hospital-based. The use of services increased for different stages of HIV infection and increased with increasing severity of HIV infection. A shift from an inpatient-based to an outpatient-based service was seen between the periods 1986 to 1991 and 1992 to 1994. As symptoms evolved, children used more hospital inpatient services, with an accompanying shift in the use of community services from general services, such as schooling, to increased use of nurses, social care and home help. The estimated total cost of hospital and community care was 18,600 Pounds per symptomatic non-AIDS patient per year and 46,600 Pounds per AIDS patient per year. Similar estimates for children with indeterminate HIV infection and asymptomatic infection amounted to 8300 Pounds and 4800 Pounds per patient-year, respectively. Nondiscounted lifetime costs for hospital care amounted to 152,400 Pounds (44,300 Pounds to 266,800 Pounds) compared with discounted lifetime costs of 122,700 Pounds (42,000 Pounds to 182,200 Pounds); nondiscounted lifetime costs for community care amounted to 24,300 Pounds (7900 Pounds to 41,600 Pounds) compared with discounted lifetime costs of 21,000 Pounds (6800 Pounds to 32,000 Pounds). CONCLUSIONS: The continued emphasis on the use of hospital services may be due to the small number of children infected with HIV, most of whom lived in the London metropolitan area where specialist care was concentrated in a few centres. A shift from an inpatient- to an outpatient-based service was observed over time; the advent of the use of combination antiretroviral therapy in this population may further facilitate a shift in service provision and promote shared care between specialist centres, local hospital and community-based services.

Anti-HIV Agents↗

Expression of a single pair of desmosomal glycoproteins renders the corneal epithelium unique amongst stratified epithelia.

PURPOSE: To determine desmosomal glycoprotein isoform expression in bovine corneal, limbal, and conjunctival epithelium and desmosomal profile and distribution during corneal re-epithelialization. METHODS: Immunofluorescence (IF) for desmosomal components on cryostat sections of fresh epithelia was supported by immunoblot analysis of tissue lysates. Wounded corneas maintained in organ culture were examined by IF at times up to full re-epithelialization (96 hours). RESULT: Immunofluorescence for desmoplakin confirmed desmosome presence throughout all three epithelia. Plakoglobin was also ubiquitous. Of the desmosomal glycoproteins, desmocollin 2 (Dsc2) and desmoglein 2 (Dsg2) were expressed throughout, but Dsc3 and Dsg3 were confined to the limbus and conjunctiva, and Dscl and Dsgl were absent. Dsc2 and Dsg2 IFs were stronger in superficial layers, but Dsc3 and Dsg3 were stronger basally, fading suprabasally. Glycoprotein expression in cornea and conjunctiva was confirmed by immunoblot analysis. No change in glycoprotein expression occurred during re-epithelialization. CONCLUSIONS: Uniquely among stratified epithelia, cornea expresses only a single pair of desmosomal glycoproteins, Dsc2 and Dsg2. Expression of Dsc3 and Dsg3 in limbus and conjunctiva coincides with their association with cell proliferation in other epithelia, but corneal epithelial cells did not express Dsc3 or Dsg3 during re-epithelialization. Absence of Dscl and Dsgl correlates with lack of keratinization in ocular epithelia. These expression patterns may have significance for the specific properties and differentiation patterns of the epithelia. Presence of desmosomes throughout re-epithelialization raises the question of how migrating cells mutually re-position.

Animals↗

IL-10 and antibodies to TGF-beta2 and PDGF inhibit RPE-mediated retinal contraction.

PURPOSE: Retinal pigment epithelial (RPE) cells are believed to play a pivotal role in the formation and contraction of epiretinal membranes in proliferative vitreoretinopathy (PVR). In the present study, an organ culture method was used that mimics the contractile stage of PVR, to investigate the contribution of a variety of growth factors in human RPE cell-mediated contraction of the retina. METHODS: Cultured human RPE cells were seeded onto bovine retinal explants. After attachment, cultures received one of the following exogenous growth factors: platelet-derived growth factor (PDGF)-AB, PDGF-BB, basic fibroblast growth factor (bFGF), transforming growth factor (TGF)-beta1, TGF-beta2, or interleukin (IL)-10; or a neutralizing antibody to PDGF and/or TGF-beta2. Control explants were either untreated or received a null antibody. Contraction was assessed by image analysis and expressed as percentage reduction in retinal area. RESULTS: RPE cells produced a more than 50% contraction of the retina after 7 days in untreated samples. PDGF and TGF-beta2 stimulated RPE-mediated contraction by a further 20% at 100 ng/ml. IL-10 decreased contraction by 63%, whereas the other growth factors gave rise to similar contraction to untreated controls. Neutralizing antibodies against PDGF and TGF-beta2 reduced RPE-mediated contraction by up to 70% in comparison with untreated controls. The neutralizing antibodies also inhibited the effects of exogenous PDGF and TGF-beta2 on RPE-mediated contraction of the retina (P < 0.01). CONCLUSIONS: These findings confirm a role for both PDGF and TGF-beta2 in RPE cell-mediated contraction of the retina. Such contraction can be inhibited by neutralizing antibodies against PDGF and TGF-beta2, which, together with IL-10, are putative candidates for therapeutic intervention in PVR.

Animals↗

Optimization of non-viral gene transfer to human primary retinal pigment epithelial cells.

PURPOSE: To optimise the high efficiency, non-viral transfer of DNA to retinal pigment epithelial (RPE) cells in vitro. METHODS: A mammalian expression vector (pcDNA3.1) containing a firefly luciferase (luc) cDNA was used to transfect RPE cells using different chemical methods; calcium phosphate, DEAE-dextran and, liposomes-based transfection techniques. Transfection was optimised for both dose and time of exposure. The efficiency of gene transfer and cytotoxicity was measured 48 hours post-transfection using luciferase and MTT assays, respectively. The percentage of transfected cells (using optimal conditions) was determined with a construct expressing a jellyfish green fluorescent protein (GFP) using flow cytometery. RESULTS: Calcium phosphate and DEAE-dextran techniques failed to transfect the vector and led to high cytotoxicity. Liposomes-based methods successfully transferred the vector to RPE cells, but the efficiency varied for different liposomes; Tfx-50 > Lipofectin > Lipofectamine > Cellfectin > DMRIE-C. No significant cytotoxicity was observed with any of the liposome treatments. Optimal transfection was achieved with Tfx-50 at a 3:1 ratio of DNA:liposome; between 12-15% of cells being transfected. CONCLUSIONS: Efficient and non-toxic transfer of functional genes into primary RPE cells in vitro can be successfuly achieved by liposomes-based techniques. Tfx-50 appears to be a promising non-viral vector for RPE gene transfer.

Aged↗

Influence of pigment content, intracellular calcium and cyclic AMP on the ability of human retinal pigment epithelial cells to contract collagen gels.

PURPOSE: The aim of the study was to determine to what extent collagen gel contraction could be reduced by calcium and calmodulin antagonists and agents that elevate cyclic AMP in order to develop a pharmacological approach to prevent/arrest RPE contraction of epiretinal membranes in proliferative vitreoretinopathy. We also explored a possible role of pigment in collagen gel contraction. METHOD: We measured RPE mediated contraction of 3D collagen gels in the presence and absence of the calcium and calmodulin antagonists TMB8, Verapamil and Tamoxifen and the cAMP elevating agents IBMX and Forskolin. The effect of pigment on collagen gel contraction was assessed by comparing gel contraction mediated by RPE cells re-pigmented with melanin with that mediated by unpigmented RPE. The effect of IBMX on RPE proliferation was assessed using a BrdU ELISA and the effects of IBMX on RPE cytoskeleton and cell shape were assessed using Actin and Cytokeratin immunocytochemistry. RESULTS: We report that both cAMP elevating agents and calcium and calmodulin antagonists reduce RPE mediated collagen gel contraction. Cyclic AMP elevation was more effective than a reduction in calcium in reducing contraction. There were no significant advantages in combining both approaches. The presence of melanin had no effect on gel contraction. Calcium antagonists and particularly agents which elevate cAMP caused RPE cells in collagen gels to extend fewer and shorter processes. cAMP elevation in particular caused RPE cells to become more rounded and develop arborized cell processes. Immunostaining for actin and cytokeratin revealed changes in cytoskeletal organisation in response to IBMX in that cells contained less actin than untreated cells and concentrated cytokeratins more centrally. CONCLUSION: We have identified two possible pharmacological approaches which may provide a new direction for preventing or slowing down the development of PVR.

1-Methyl-3-isobutylxanthine↗

The photoreactivity of the retinal age pigment lipofuscin.

The presence of the age pigment lipofuscin is associated with numerous age-related diseases. In the retina lipofuscin is located within the pigment epithelium where it is exposed to high oxygen and visible light, a prime environment for the generation of reactive oxygen species. Although we, and others, have demonstrated that retinal lipofuscin is a photoinducible generator of reactive oxygen species it is unclear how this may translate into cell damage. The position of lipofuscin within the lysosome infers that irradiated lipofuscin is liable to cause oxidative damage to either the lysosomal membrane or the lysosomal enzymes. We have found that illumination of lipofuscin with visible light is capable of extragranular lipid peroxidation, enzyme inactivation, and protein oxidation. These effects, which were pH-dependent, were significantly reduced by the addition of the antioxidants, superoxide dismutase and 1,4-diazabicyclo(2,2,2)-octane, confirming a role for both the superoxide anion and singlet oxygen. We postulate that lipofuscin may compromise retinal cell function by causing loss of lysosomal integrity and that this may be a major contributory factor to the pathology associated with retinal light damage and diseases such as age-related macular degeneration.

Aged↗

General practice and the care of children with HIV infection: 6 month prospective interview study.

OBJECTIVES: To describe the use of primary care services by children infected with HIV and to explore the attitudes of their parents to the role of general practitioners in their children's care. DESIGN: A 6 month prospective study. Quantitative analysis of "contact diaries" kept by parents; qualitative analysis of face to face interviews with parents. PARTICIPANTS: Parents of children receiving care at a regional referral centre in London. RESULTS: Twenty four families (80% response rate) were recruited to the study. In 19 families the mother was black African. Half the children had been diagnosed with symptomatic HIV infection, half with AIDS. All the children were registered with a general practitioner who knew of the child's HIV infection. In five families there had initially been tensions in their relationship with their general practitioner but by the time of the study all but one family had established at least an "acceptable" relationship. Children with symptomatic HIV infection saw their general practitioner a mean of 7.5 times per patient year; for children with AIDS the figure was 5.8. Parents regarded the paediatric HIV team at the hospital as their primary source of medical care. Three factors constrained their use of general practice: their own anxieties about distinguishing "normal" symptoms from those related to HIV infection; their view that their general practitioner did not feel competent to treat HIV infected children; and their concerns about maintaining confidentiality in the surgery. CONCLUSIONS: Parents remain oriented towards the paediatric HIV team as their primary source of medical care and use general practice largely for routine prescriptions for their children. Any further development of the general practitioner's role will need to build on existing relationships with specialist providers and take account of parents' concerns.

Child↗

An analysis of first-time enquirers to the CancerBACUP information service: variations with cancer site, demographic status and geographical location.

A retrospective comparison of cancer incidence data and, where relevant, population data with 16,955 first-time users (patients, relatives and friends) of a national cancer information service (CancerBACUP) during the period April 1995 to March 1996 is presented. The number of events observed was compared with the number of events expected, were the national rates of cancer incidence and population demographics apply. Standardized incidence ratios (SIRs) (observed - expected ratios) were used to indicate any differences. Statistically significant differences (P < 0.001) in the observed and expected sex, age and primary site distribution of patients enquired about were found. Statistically significant differences (P < 0.001) were also identified for the age, employment status, socioeconomic class and geographical location of first-time enquirers (patients, relatives and friends). Enquiries about brain, testis and breast cancers and non-Hodgkin's lymphoma (NHL) were substantially higher than expected; enquiries about bladder, lung, stomach and colorectal cancers were much lower than expected. As the service is provided via a freephone number, it is available to all, and users might be expected to be randomly distributed across the variables listed. The underlying reasons for the differences identified need to be investigated, and the role of information in the care of cancer patients should be formally evaluated.

Adult↗

What is the cost of getting the price wrong?

BACKGROUND: The objective of this study was to compare differences in cost estimates for paediatric HIV hospital service provision based on hospital prices with cost estimates obtained through a research-based service-specific costing exercise. METHODS: Activity data on the use of hospital services of children by stage of HIV infection were collected from case-notes for 118 HIV antibody positive children, managed at St Mary's Hospital NHS Trust, London, 1 January 1986-31 December 1994. Hospital unit prices were obtained from the Hospital Trust Finance Department; unit cost estimates were obtained from relevant hospital departments through a research-based service-specific costing exercise. Financial data related to the 1993-1994 financial year, and were indexed to 1995-1996 prices. The main outcome measures were cost estimates per patient-year by stage of HIV infection. Three cost scenarios were calculated: first by linking activity data with hospital prices (Trust Prices); second by linking activity data with routinely available hospital prices plus units costs from the costing exercise where no relevant hospital prices existed (Supplemented Trust Prices); third, by linking activity data exclusively with unit costs from the hospital-specific costing exercise (Unit Costs). RESULTS: There were substantial differences between unit cost estimates per patient-year based on Trust Prices and Supplemented Trust Prices compared with those based on Unit Costs. Differences increased with more intense use of services. The deficit based on Trust Prices compared with Unit Costs ranged from Pound Sterling 432 per patient-year for HIV negative children, Pound Sterling 574 for asymptomatic HIV-infected children, Pound Sterling 1288 for indeterminate children, Pound Sterling 1814 for children with symptomatic non-AIDS to Pound Sterling 7418 per patient-year for children with AIDS. CONCLUSIONS: In this hospital, reliance on generic hospital prices to derive cost estimates for paediatric HIV services produced considerable underestimates of the cost of service provision compared with data derived through the costing exercise. If this occurs across all or most areas of service provision, this can lead to substantial financial deficits, which in turn may mean that the needs of specific client populations may not be met.

Bias↗

Immunolocalisation of the VEGF receptors FLT-1, KDR, and FLT-4 in diabetic retinopathy.

AIM: To determine the spatial and temporal changes in the staining pattern of the VEGF receptors FLT-1, KDR, and the putative receptor FLT-4 during the pathogenesis of diabetic retinopathy. METHODS: Immunohistochemical localisation of VEGF receptors, using antibodies against FLT-1, FLT-4, and KDR, was carried out on specimens of normal human retina (n = 10), diabetic retinas (a) with no overt retinopathy (n = 12), (b) with intraretinal vascular abnormalities but no proliferative retinopathy (n = 5), (c) with active proliferative retinopathy (n = 6), and (d) with no residual proliferative retinopathy after scatter photocoagulation therapy (n = 14), and surgically excised diabetic fibrovascular membranes (n = 11). The degree and pattern of immunostaining was recorded. RESULTS: FLT-1 staining was apparent in the retinas from both non-diabetic and diabetic retinas; weak to moderate staining was generally confined to the inner nuclear layer, the ganglion cell layer, and the retinal vessels during all stages of the disease process. Staining of the retinal vessels was raised in diabetic tissue compared with non-diabetic tissue. The preretinal vessels of the diabetic subjects stained moderately to intensely for FLT-1. In contrast with FLT-1 staining minimal immunostaining for KDR was demonstrated in the non-diabetic eyes and the unlasered eyes; however, weak staining for KDR was observed in the inner nuclear layer and the ganglion cell layer of the unlasered eyes with diabetic changes. In those retinas with preretinal neovascularisation KDR immunoreactivity was moderate to intense in the intra- and preretinal vessels. However, in the excised membranes, where the vessels may have been in a quiescent state, the levels of KDR were weak to moderate. After apparently successful laser treatment KDR staining was reduced in the intraretinal vessels. Minimal FLT-4 staining was observed throughout normal eyes while weak to moderate FLT-4 staining was generally confined to the inner nuclear layer and the ganglion cell layer of the unlasered diabetic eyes. Weak to moderate levels of FLT-4 staining were observed in the intraretinal vessels except after apparently successful laser treatment where reduced levels of staining were observed. Weak to moderate staining was observed in the preretinal vessels. CONCLUSIONS: This study supports a role for FLT-1, KDR, and possibly FLT-4 in the pathogenesis of diabetic retinopathy; however, their specific roles in the progression of the disease may differ.

Aged↗

Growth factor staining patterns in the pig retina following retinal laser photocoagulation.

AIM: To identify changes in growth factor expression in miniature pig retinas following retinal laser photocoagulation. METHODS: Pigs were sacrificed at different times (15 minutes to 42 days) post-laser and the retinas were immunolabelled for basic fibroblast growth factor, insulin-like growth factor I, transforming growth factor beta, epidermal growth factor, transforming growth factor alpha, platelet derived growth factor, vascular endothelial growth factor, and epidermal growth factor receptor. Total mRNA levels were also determined. RESULTS: With the exception of vascular endothelial growth factor, immunoreactivity for all other growth factors studied and epidermal growth factor receptor was observed throughout normal non-lasered control retina, generally being high in the retinal pigment epithelium and low in the neural retina. Changes in growth factor expression following laser photocoagulation were observed only in burn areas and changes were mainly confined to the retinal pigment epithelium and outer nuclear layer. The immunoreactivity within retinal pigment epithelial cells in burn areas was either absent or decreased following laser treatment but returned to normal by 21 days. The immunoreactivity was increased within the outer nuclear layer of burn areas during the healing process but returned to normal by 42 days. Vascular endothelial growth factor immunoreactivity was weak/absent in the normal retina and remained unchanged following laser photocoagulation. Change of total mRNA levels in burn areas during time post-laser was confined to retinal pigment epithelial cells, being low immediately following photocoagulation and returning to normal by 42 days. CONCLUSIONS: These results demonstrate a temporal alteration in growth factor expression and transcriptional activity in the retina following laser photocoagulation.

Animals↗

Contribution of extracranial lymphatics and arachnoid villi to the clearance of a CSF tracer in the rat.

The objective of this study was to determine the relative roles of arachnoid villi and cervical lymphatics in the clearance of a cerebrospinal fluid (CSF) tracer in rats. 125I-labeled human serum albumin (125I-HSA; 100 micrograms) was injected into one lateral ventricle, and an Evans blue dye-rat protein complex was injected intravenously. Arterial blood was sampled for 3 h. Immediately after this, multiple cervical vessels were ligated in the same animals, and plasma recoveries were monitored for a further 3 h after the intracerebroventricular injection of 100 micrograms 131I-HSA. Tracer recovery in plasma at 3 h averaged (%injected dose) 0.697 +/- 0.042 before lymphatic ligation and dropped significantly to 0.357 +/- 0. 060 after ligation. Estimates of the rate constant associated with the transport of the CSF tracer to plasma were also significantly lower after obstruction of cervical lymphatics (from 0.584 +/- 0. 072/h to 0.217 +/- 0.056/h). No significant changes were observed in sham-operated animals. Assuming that the movement of the CSF tracer to plasma in lymph-ligated animals was a result of arachnoid villi clearance, we conclude that arachnoid villi and extracranial lymphatic pathways contributed equally to the clearance of the CSF tracer from the cranial vault.

Animals↗