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Biomedical subjects

M Reis

Publications and source records attributed to M Reis.

At least 19 recordsLinked to original sources

Familial breast cancer: management of 'lower risk' referrals.

Up to 40% of referrals from primary care to 'breast cancer family clinics' prove to be of women whose assessed risk falls below the guidelines' threshold for management in secondary or tertiary care, despite recommendations that they should be screened out at primary care level. A randomised trial, involving 87 such women referred to the Tayside Familial Breast Cancer Service compared two ways of communicating risk information, letter or personal interview. Both were found to be acceptable to referred women and to their family doctors, although the former expressed a slight preference for interview. Only four women returned to their family doctors with continuing concerns about breast cancer. Nevertheless, understanding of information provided by either route was unsatisfactory, with apparent confusion about both absolute and relative risks of breast cancer. Substantial minorities appear to believe that they are at no increased risk at all, or even below the population level of risk, while others remain convinced that their personal risk has been underestimated. Family history record forms, completed by the referred women, preferably with the assistance of relatives, are crucial to full assessment of familial risk but one quarter of women referred to the Tayside Familial Breast Cancer Service currently do not complete and return these forms ahead of their clinic appointment. Further collaboration between primary care and the Breast Cancer Family Service is required to improve provision for concerned women whose risks fall below the threshold for special surveillance and to maximise effective use of the family history record form.

Breast Neoplasms↗

Structure-activity relationship study of flavone compounds with anti-HIV-1 integrase activity: a density functional theory study.

Human immunodeficiency virus type-1 integrase (HIV-1 IN) is an essential enzyme for effective viral replication. Flavone compounds have been very much studied due to their activity during the inhibition process of HIV-1 IN. In this study, we employed density functional theory (DFT) using the B3LYP hybrid functional to calculate a set of molecular properties for 32 flavonoid compounds with anti-HIV-1 IN activity. The stepwise discriminant analysis (SDA), principal component analysis (PCA) and hierarchical cluster analysis (HCA) methods were employed to reduce dimensionality and investigate possible relationship between the calculated properties and the anti-HIV-1 IN activity. These analyses showed that the molecular hydrophobicity (ClogP), charge on atom 11 and electrophilic index (omega) are responsible for the separation between anti-HIV-1 IN active and inactive compounds.

Cluster Analysis↗

[Priapism].

Priapism is a rare disease, characterized by a prolonged erection unrelated to sexual stimulus or desire. There are two distinct types of priapism with different etiologies, pathophysiology, treatment and complications. A better understanding of these two clinical entities brought about, in recent years, some progress in their treatment. The authors make a retrospective analysis of the 17 cases of priapism diagnosed in this centre in the last twelve years. From this experience they review the standard approach to this disease, both diagnostic and therapeutic.

Adult↗

Simultaneous changes in the function and expression of beta 1 integrins during the growth arrest of poorly differentiated colorectal cells (LISP-1).

Cells usually lose adhesion and increase proliferation and migration during malignant transformation. Here, we studied how proliferation can affect the other two characteristics, which ultimately lead to invasion and metastasis. We determined the expression of beta 1 integrins, as well as adhesion and migration towards laminin-1, fibronectin, collagens type I and type IV presented by LISP-1 colorectal cancer cells exposed to 2.5% dimethyl sulfoxide (DMSO), an agent capable of decreasing proliferation in this poorly differentiated colorectal cell line. Untreated cells (control), as shown by flow cytometry and monoclonal antibodies, expressed alpha 2 (63.8 11.3% positive cells), alpha 3 (93.3 7.0%), alpha 5 (50.4 12.0%) and alpha 6 (34.1 4.9%) integrins but not alpha1, alpha 4, alpha v or 4. Cells adhered well to laminin-1 (73.4 6.0%) and fibronectin (40.0 2.0%) substrates but very little to collagens. By using blocking monoclonal antibodies, we showed that alpha 2, alpha 3 and alpha 6 mediated laminin-1 adhesion, but neither alpha 3 nor alpha 5 contributed to fibronectin adherence. DMSO arrested cells at G0/G1 (control: 55.0 2.4% vs DMSO: 70.7 2.5%) while simultaneously reducing alpha 5 (24.2 19%) and alpha 6 (14.3 10.8%) expression as well as c-myc mRNA (7-fold), the latter shown by Northern blotting. Although the adhesion rate did not change after exposure to DMSO, alpha 3 and alpha 5 played a major role in laminin-1 and fibronectin adhesion, respectively. Migration towards laminin-1, which was clearly increased upon exposure to DMSO (control: 6 2 cells vs DMSO: 64 6 cells), was blocked by an antibody against alpha 6. We conclude that the effects of DMSO on LISP-1 proliferation were accompanied by concurrent changes in the expression and function of integrins, consequently modulating adhesion/migration, and revealing a complex interplay between function/expression and the proliferative state of cells.

Cell Adhesion↗

Bcl-2 clearance: optimising outcomes in follicular non-Hodgkin's lymphoma.

The long median survival time of patients with follicular non-Hodgkin's lymphoma (NHL), means that the efficacy of new treatments are difficult to assess in the short term. Bcl-2 is an inhibitor of apoptosis and overexpression of the bcl-2 gene in the blood or bone marrow is a feature in up to 85% of patients with follicular NHL. Levels of bcl-2(+) cells in the peripheral blood or bone marrow therefore are a useful measure of disease status in such patients and can be detected by polymerase chain reaction (PCR). Complete bcl-2 clearance from the bone marrow (molecular remission) following autologous stem cell transplant (ASCT) for follicular NHL is considered to be an important prognostic factor for disease-free survival. Tumour cell contamination of the stem cell grafts used in ASCT is commonly associated with relapse. This can be addressed by purging the stem cell harvest prior to transplantation. Various methods of in vitro purging after stem cell collection have been shown to reduce the level of contamination but yield is invariably reduced and grafts remain bcl-2 positive. However, in vivo purging with rituximab during the process of collection has been used to obtain bcl-2-negative stem cell harvests without compromising the yield. Rituximab is a monoclonal antibody licensed for treatment of relapsed and refractory low-grade or follicular NHL. Rituximab targets the CD20 antigen, which is found on cells of the B cell lineage. When used for in vivo purging it depletes the peripheral blood of CD20-positive cells and prevents contamination by lymphoma cells. Molecular remission, as measured by bone-marrow bcl-2 clearance, has been achieved in 7/7 patients with follicular NHL at 1 year after treatment with ASCT using rituximab as an 'in vivopurse', followed by rituximab maintenance. Early clinical outcomes are also encouraging.

Antibodies, Monoclonal↗

Malignant evolution of Schnitzler's syndrome--chronic urticaria and IgM monoclonal gammopathy: report of a new case and review of the literature.

Schnitzler's syndrome, initially described in 1974 is an uncommon condition defined by chronic urticaria and monoclonal IgM gammopathy. Additional features include fever of unknown origin, elevated ESR, bone pain and frequently a benign clinical course. We conducted a literature search of Medline, EMBASE and Cancerlit and found 56 cases of Schnitzler's syndrome reported to date. The absence of lymphoproliferative disease in this condition is typical, but nine patients have progressed to develop lymphoplasmacytic neoplasias, particularly Waldenstrom's macroglobulinemia (WM). Malignant evolution of Schnitzler's syndrome is a rare complication, but emphasizes the importance of long term follow-up and the need for these patients to undergo periodic assessment of the bone marrow and lymph nodes. Treatment of this condition is difficult, with varying response to corticosteroids and largely unsuccessful results with standard chemotherapy used for WM. We describe a case of Schnitzler's syndrome in a 50-year old man with lymphocytic aggregates in the bone marrow after 9 years of chronic urticaria, fever, arthralgias and bone pain. We review the clinical features and treatment, with emphasis on the hematologic aspects of this unusual condition.

Bone Marrow↗

Correlation between uncoupled ATP hydrolysis and heat production by the sarcoplasmic reticulum Ca2+-ATPase: coupling effect of fluoride.

The sarcoplasmic reticulum Ca(2+)-ATPase transports Ca(2+) using the chemical energy derived from ATP hydrolysis. Part of the chemical energy is used to translocate Ca(2+) through the membrane (work) and part is dissipated as heat. The amount of heat produced during catalysis increases after formation of the Ca(2+) gradient across the vesicle membrane. In the absence of gradient (leaky vesicles) the amount of heat produced/mol of ATP cleaved is half of that measured in the presence of the gradient. After formation of the gradient, part of the ATPase activity is not coupled to Ca(2+) transport. We now show that NaF can impair the uncoupled ATPase activity with discrete effect on the ATPase activity coupled to Ca(2+) transport. For the control vesicles not treated with NaF, after formation of the gradient only 20% of the ATP cleaved is coupled to Ca(2+) transport, and the caloric yield of the total ATPase activity (coupled plus uncoupled) is 22.8 kcal released/mol of ATP cleaved. In contrast, the vesicles treated with NaF consume only the ATP needed to maintain the gradient, and the caloric yield of ATP hydrolysis is 3.1 kcal/mol of ATP. The slow ATPase activity measured in vesicles treated with NaF has the same Ca(2+) dependence as the control vesicles. This demonstrates unambiguously that the uncoupled activity is an actual pathway of the Ca(2+)-ATPase rather than a contaminating phosphatase. We conclude that when ATP hydrolysis occurs without coupled biological work most of the chemical energy is dissipated as heat. Thus, uncoupled ATPase activity appears to be the mechanistic feature underlying the ability of the Ca(2+)-ATPase to modulated heat production.

Adenosine Triphosphatases↗

ALVAC-mediated gene transfer is efficient in lymphoid malignancies of T-and early B-cell origin, but not in tumors arising from mature B-cells.

Natural attenuation of ALVAC virus in mammals makes it an attractive vector for cancer vaccine therapy of immunocompromised hosts, such as patients with lymphoid malignancies. However, the transduction efficiency of ALVAC constructs in lymphoid tumors has not yet been characterized. We studied a wide spectrum of human T- and B-cell leukemia and lymphomas and found significant heterogeneity of the ALVAC-mediated gene product expression in these tumors. While ALVAC-B7.1, ALVAC-B7.2, or ALVAC-luciferase vectors effectively expressed recombinant genes in malignancies arising from T- or early B-cell precursors, negative or low expression of ALVAC recombinant genes occurred in tumors arising from mature B-cells. We showed that ALVAC-encoded B7.1 or B7.2 was continuously expressed on the infected, and subsequently irradiated, leukemia cells, and only cells with ALVAC-mediated expression of costimulatory molecules (but not unmodified leukemia cells or those infected with the ALVAC-parental vector) induced significant proliferation and IFN-gamma production by alloreactive T-cells. These data provide the rationale for clinical studies using the ALVAC vector system for gene transfer into lymphoid tumors of T- and early B-cell origin to render them more immunogenic, while alternative strategies should be considered for immunotherapy of mature B-cell malignancies.

Animals↗

Gender influences handwashing rates in the critical care unit.

BACKGROUND: Nurses tend to wash their hands more often than physicians, and among nonhealth care workers, women tend to wash their hands more often than men. This study examined the influence of gender on the handwashing rates of health care workers (HCWs). The null hypotheses were that there would be no intergender difference in (a) handwashing rates in HCWs across professions and (b) within professional groups. METHODS: Handwashing by nurses, physicians, wardspersons, x-ray technicians, and physiotherapists after patient contact in a critical care unit (CCU) was determined through covert observation. The gender and profession of the subjects were recorded, but their identity was not. RESULTS: Female CCU staff washed their hands significantly more often than did their male counterparts after patient contact (P =.0001). When the results were examined for the influence of profession on handwashing, significant intergender differences remained for physicians (P =.0468) and wardspersons (P =.0001). There was also a nonsignificant trend (P =.07) toward higher rates of handwashing among female x-ray technicians. There were no statistically significant intergender differences in handwashing rates among nurses (P =.7588) and physiotherapists. CONCLUSIONS: It appears that gender may influence handwashing rates in HCWs in the CCU, although this difference appears to be modified in particular professional groups. Further research should examine factors that modify handwashing rates within professional groups and in settings other than the CCU.

Allied Health Personnel↗

Serum concentrations of fluoxetine in the clinical treatment setting.

This article discusses fluoxetine serum concentrations as displayed in a clinical setting. A racemic serum fluoxetine and norfluoxetine high-performance liquid chromatography method, including ultraviolet light detection, was used for routine therapeutic drug monitoring (TDM) purposes. In all, 508 samples were analyzed. For the scientific investigation, predefined inclusion and exclusion criteria were applied and 150 samples representative of trough values in steady-state conditions with essential clinical information provided on the assay request forms were evaluated. Fluoxetine plus norfluoxetine concentration-to-dose (C/D) ratio showed Gaussian distribution. Interindividual coefficients of variation of fluoxetine and norfluoxetine serum concentrations after different doses were found to be 40-63%. Intraindividual fluoxetine TDM variability was low. The Spearman rank correlation coefficient for fluoxetine and norfluoxetine C/D ratios in first and second samples was 0.68. Minor increases in norfluoxetine C/D and fluoxetine plus norfluoxetine C/D ratios were found in elderly patients compared with younger adult patients. A higher body-mass index was associated with minor decreases in fluoxetine and fluoxetine plus norfluoxetine C/D ratios. New fluoxetine pharmacokinetic data are added to the results from earlier phases of drug development. Moreover, the results of this study support the usefulness of a fluoxetine TDM procedure for individual dose optimization, detection of drug interactions, and assessments of patient compliance.

Adolescent↗

Enantioselective analysis of citalopram and metabolites in adolescents.

Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent despite its increasing use in these age groups. The aim of this study was to investigate a group of adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites desmethylcitalopram and didesmethylcitalopram. Moreover, the authors studied the genotypes for the polymorphic cytochrome P450 enzymes CYP2D6 and CYP2C19 in relation to the different enantiomers. The S/R ratios of citalopram and desmethylcitalopram found in this study of 19 adolescents were similar to studies involving older patients. The concentrations of the R-(-)- and S-(+)-enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies, the R-(-)-enantiomer (distomer) being the major enantiomer. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the CYP2C19 enzyme.

Adolescent↗

Establishment of a cytokine-producing anaplastic large-cell lymphoma cell line containing the t(2;5) translocation: potential role of cytokines in clinical manifestations.

A permanent cell line, HSC-M1, was established from a child with advanced CD30 (Ki-1)+ anaplastic large-cell lymphoma (ALCL). Clinical features included irritability, fever, weight loss, tender lymphadenopathy, pneumonitis, neutrophilia, and bone marrow erythrophagocytosis. While HSC-M1 cells exhibited an immunophenotype characteristic of ALCL of T-cell lineage, the cell line also demonstrated features of monocyte-macrophage lineage. Cytogenetic and polymerase chain reaction (PCR) analysis of the HSC-M1 cell line and involved bone marrow demonstrated the characteristic non-random chromosomal translocation t(2:5)(p23:q35). Reverse transcriptase PCR for mRNA expression of cytokines and cytokine receptors showed that HSC-M1 cells expressed the message for multiple cytokines and their receptors. Measurement of cytokine levels in serum samples using enzyme-linked immunosorbent assays showed increased concentrations of several cytokines. The increased levels of some cytokines correlated with disease activity and clinical symptoms. Although spontaneous production by HSC-M1 cells of some of these cytokines was demonstrated, the production of others was only detectable after stimulation with exogenous CD30 ligand. With few exceptions, there was good correlation between serum cytokine levels and cytokines produced by HSC-M1 cells. These findings indicate that cytokine production is a feature of ALCL cells and that some of the clinical manifestations in ALCL may result from cytokines produced by either the malignant or accessory cells.

Chromosomes, Human, Pair 2↗

Chloride-dependent inhibition of vesicular glutamate uptake by alpha-keto acids accumulated in maple syrup urine disease.

Maple syrup urine disease is a metabolic disorder caused by mutations of the branched chain keto acid dehydrogenase complex, leading to accumulation of alpha-keto acids and their amino acid precursors in the brain. We now report that alpha-ketoisovaleric, alpha-keto-beta-methyl-n-valeric and alpha-ketoisocaproic acids accumulated in the disease inhibit glutamate uptake into rat brain synaptic vesicles. The alpha-keto acids did not affect the electrochemical proton gradient across the membrane, suggesting that they interact directly with the vesicular glutamate carrier. Chloride anions have a biphasic effect on glutamate uptake. Low concentrations activate the uptake (0.2 to 8 mM), while higher concentrations are inhibitory. The alpha-keto acids inhibited glutamate uptake by a new mechanism, involving a change in the chloride dependence for the activation of glutamate uptake. The activation of glutamate uptake by low chloride concentrations was shifted toward higher concentrations of the anion in the presence of alpha-keto acids. Inhibition by alpha-keto acids was abolished at high chloride concentrations (20 to 80 mM), indicating that alpha-keto acids specifically change the stimulatory effect of low chloride concentrations. High glutamate concentrations also reduced the inhibition by alpha-keto acids, an effect observed both in the absence and in the presence of low chloride concentrations. The results suggest that in addition to their possible pathophysiological role in maple syrup urine disease, alpha-keto acids are valuable tools to study the mechanism of vesicular transport of glutamate.

ATP-Binding Cassette Transporters↗

Maximising handwashing rates in the critical care unit through yearly performance feedback.

Handwashing following patient contact reduces the incidence of nosocomial infections. Despite this, handwashing rates by health care workers (HCWs) are often poor. Feedback on handwashing has been shown to significantly improve its rates. This study determined the optimum time to repeat performance feedback on handwashing rates of hospital staff in order to maximise its incidence. The baseline incidence of handwashing by staff following patient contact was determined by covert observation. This was followed by a period of feedback on handwashing performance by means of histograms displayed in the unit. Handwashing incidence was reassessed 6 and 12 months after the feedback ended. Performance feedback induced significant increases in handwashing incidence amongst nurses (p = 0.0433), resident medical officers (p = 0.0134), specialists (p = 0.0021) and radiographers (p = 0.0001). Non-significant increases were noted in handwashing rates amongst wardsmen/women and physiotherapists. Overall, handwashing incidence declined significantly (p = 0.0001) 12 months post feedback. This study demonstrated that feedback should be repeated within 12 months in order to maximise handwashing rates with the minimum intervention.

Critical Care↗

Therapeutic drug monitoring of selective serotonin reuptake inhibitors influences clinical dosing strategies and reduces drug costs in depressed elderly patients.

OBJECTIVE: This study was initiated in order to describe and evaluate the effects of a therapeutic drug monitoring (TDM) routine of selective serotonin reuptake inhibitors (SSRIs) on treatment strategies and drug costs in depressed elderly patients. METHOD: Blood samples were drawn from elderly depressed patients and analysed for steady-state trough serum concentrations of citalopram (n = 48), paroxetine (n = 48) or sertraline (n = 39). A global efficacy evaluation was made at baseline and after 6-9 months. Antidepressant drug costs before and after TDM were estimated. RESULTS: Eight samples were excluded due to technical problems or noncompliance. In 65 of the 127 (51.2%) remaining cases, the treatment strategy was changed according to the TDM outcome, in most a reduction of the prescribed dose. Bioanalytical TDM costs included the antidepressant drug costs after TDM were reduced by 10.2%. CONCLUSION: The results support the utility of TDM in the search for the individual minimum effective SSRI dose in the elderly.

Aged↗

Therapeutic drug monitoring of sertraline: variability factors as displayed in a clinical setting.

This report describes sertraline pharmacokinetics derived from routine therapeutic drug monitoring (TDM) data. A high-performance liquid chromatographic method with ultraviolet detection was established for routine sertraline TDM, and 924 analyses were performed from April 1995 to May 1997. Extensive predefined inclusion/exclusion criteria were applied to increase the validity of scientifically evaluated data. Subsequently, 605 samples (65.5%) were excluded. The remaining 319 samples from 319 patients, representative of steady state trough specimens and accompanied by essential clinical information provided on request forms, were scrutinized. A pronounced interindividual variability was observed. Smokers had significantly lower concentration-to-dose (C/D) mean ratios of serum sertraline (s-sert) and its main metabolite desmethylsertraline (s-dsert) than nonsmokers. Higher s-sert and s-dsert C/D mean ratios were found in elderly patients than in adults aged less than 65 years. In a subset of 20 patients in whom repeated TDM analyses were performed, observed intraindividual sertraline TDM outcome variability was low. The results highlight sertraline TDM as a tool for individual dose optimization and evaluation of patient drug compliance as well as drug-drug interactions.

Adolescent↗

Hepatitis B and hepatitis C prevalence among blood donors and HIV-1 infected patients in Florianópolis--Brazil.

Information is scarce on the prevalence of hepatitis B (HBV) and hepatitis C (HCV) among voluntary blood donors and patients infected with the human immunodeficiency virus (HIV) in Florianópolis, Brazil. A total of 2,678 serum samples from 2,583 blood donors and 95 HIV-infected patients, collected between April, 1994, and March, 1995, were examined for markers of HBV and HCV. All the samples were analyzed to detect HBV and HCV markers (HBsAg, anti-HBc, and anti-HCV). Hepatitis B and C prevalence among the studied blood donors reached 9.3% and 1.0%, respectively; 0.7% being seropositive for HBsAg and 9.2% for anti-HBc. It was also verified that 0.1% of blood donors were seropositive for HBsAg alone, 8.6% seropositive for the anti-HBc alone, and 0.6% presented a positive reaction for both of the HBV markers studied. Among HIV-infected patients, prevalence of 69.5% and 54.7% for hepatitis B and hepatitis C, respectively, were observed. Of these patients, 18.9% were seropositive for HBsAg, and 66.3% for the anti-HBc. The prevalence of a reaction for HBsAg alone, and for anti-HBc alone was 3.1% and 50.5%, respectively, for HIV-infected patients, whereas 15.8% were seropositive for both of the studied markers. HBV and HCV coinfection was 0.1% in blood donors, and 40% of those patients tested seropositive for HIV. Results show prevalence of HBV and HCV infection to be significantly greater among HIV-infected patients than among blood donors. These observations confirm the high frequency of HIV-infected patients exposure to these other viruses.

Blood Donors↗