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Biomedical subjects

A Lucas

Publications and source records attributed to A Lucas.

At least 19 recordsLinked to original sources
PubMed2006

Disturbed in vitro adrenergic modulation of cytokine production in inflammatory bowel diseases in remission.

OBJECTIVE: Psychological stress has been implicated in the pathophysiology of both inflammatory and functional gastrointestinal (GI) diseases. The goal of this study was to address neuroendocrine modulation of cytokine production by peripheral blood cells in GI diseases. METHODS: We analyzed the in vitro effects of the beta-adrenergic agonist terbutaline and the glucocorticoid agonist dexamethasone on TNF-alpha and IL-10 production by LPS-stimulated monocytes in whole cell blood cultures in patients with inflammatory bowel diseases in remission (N=10), diarrhoea-predominant irritable bowel syndrome (IBS, N=12), patients with a recent gastroenteritis (post-infectious group, N=10), and healthy controls (N=15). RESULTS: In response to terbutaline, there was a significant increase in IL-10 production (concentration effect: p<0.05), which was diminished in IBD (group effect: p<0.01), comparable in IBS and controls, but enhanced in the post-infectious group (group x concentration effect: p<0.05). In contrast, terbutaline resulted in a concentration-dependent suppression of TNF-alpha production, which was comparable in all groups. Dexamethasone suppressed TNF-alpha production in a dose-dependent manner in all groups, but this effect was significantly more pronounced in post-infectious subjects (group effect: p<0.05). CONCLUSIONS: In IBD, disturbed adrenergic regulation of IL-10 could be part of the mechanism(s) underlying the modulation of disease activity by psychological stress. Diarrhoea-predominant IBS was not associated with altered adrenergic or glucocorticoid regulation of cytokine production by peripheral blood cells, whereas a recent history of gastroenteritis was associated with disturbed neuroendocrine modulation of cytokine production, which may play role in the pathophysiology of post-infectious IBS.

Adrenergic beta-Agonists↗
PubMed2006

A simplified approach to analysing bio-electrical impedance data in epidemiological surveys.

BACKGROUND: Bio-electrical impedance analysis (BIA) is widely used to estimate body composition. It is simple, quick and cheap, but less accurate than other methods. It has potential epidemiological value, but has conventionally required validation before application. AIMS: To develop a simple method of expressing weight, height and impedance data that avoids the need for population-specific validation equations in order to facilitate epidemiological application. METHODS: Body composition was measured using the four-component model in young adults (43 males, 90 females). Impedance (R) was measured hand-foot and foot-foot. Lean mass and fat mass were adjusted for height to give lean mass index (LMI) and fat mass index (FMI). Based on theoretical principles, we generated the index 1/R, which provides an index of body water adjusted for height. Sex-specific regression models were used to investigate the relationships between (a) 1/R and LMI, and (b) body mass index (BMI) adjusted for 1/R and FMI. The success of this approach was evaluated in relation to the conventional BIA approach, using correlation analysis. RESULTS: 1/R was a highly significant predictor of LMI. BMI adjusted for 1/R was a significant predictor of FMI. Our approach performed as well as the conventional approach for LMI, but not for FMI. DISCUSSION: Direct use of BIA data, rather than their combination with population-specific equations for the prediction of total body water, proved successful at ranking individuals of both sexes in terms of LMI and FMI. The index 1/R may prove particularly valuable in epidemiological studies where ranking of LMI is required.

Adipose Tissue↗
PubMed2006

Visceral pain and public speaking stress: neuroendocrine and immune cell responses in healthy subjects.

Whereas responses to psychological stressors are well-characterized, little is known regarding responses to painful visceral stimuli. We analyzed the emotional, cardiovascular, neuroendocrine, and cellular immune responses to painful rectal stimulation and psychological stress in healthy individuals. Eleven healthy subjects were studied in three conditions on separate days: painful rectal distension, public speaking stress, and rest. Blood was drawn for endocrinological and immunological analyses; heart rate and blood pressure were measured continuously; state anxiety was assessed with a questionnaire (STAI-S). Anxiety scores were highest in the rectal distension condition. This was evident following rectal distension (mean STAI-S scores: 44.2+/-3.5 post-distension vs. 36.6+/-3.8 post-speech, p<.05), but anxiety was also elevated at baseline (41.6+/-3.9 vs. 32+/-3.2 recovery, p<.01). This anticipatory effect was reflected by elevated baseline cortisol (p<.05) and baseline ACTH (p<.01) levels, as well as circulating lymphocytes and lymphocyte subsets, including decreased basal CD3+CD4+ cells (p<.05) and increased CD16+CD56+ cells (p=.06) compared to rest. Both public speech and rectal distension induced cardiovascular activation, but the effect was more pronounced following rectal distension (+63.8+/-9.4 mmHg in response to distension vs. +36.4+/-6.2 mmHg in response to speech for systolic BP, p<.05). Different response patterns were also observed in the distribution of circulating leukocytes and lymphocyte subsets, including CD16+CD56+ cells (p<.05). An acute visceral pain stimulus causes profound emotional, neuroendocrine, and immune cell responses, which are markedly affected by anticipatory anxiety. These findings may have implications for conditions associated with visceral hyperalgesia.

Adult↗
PubMed2006

[Brooke-Spiegler syndrome: an heterogeneous entity].

The Brooke-Spiegler syndrome is a rare, autosomally dominant disease with a predisposition to develop different adnexal tumors. Clinically it is characterized by the presence of multiple cylindromas, trichoepitheliomas, and occasionally, spiradenomas. Although Brooke-Spiegler syndrome, familial cylindromatosis and multiple familial trichoepithelioma were initially described as separate entities, the recently identified identical mutations in the gene of cylindromatosis suggest that they represent fenotypic variations of the same entity. In this article we present the case of a woman and her daughter, both affected by this rare genodermatosis.

Adult↗
PubMed2006

[Influence of different surface machining treatments of resorbable implants made from different magnesium-calcium alloys on their degradation--a pilot study in rabbit models].

To examine the influence of different surface machining treatments of resorbable implants 3x5 mm cylinders of magnesium-calcium-alloys with plane, rough or sand blasted surface and different concentrations of calcium (0.4 %, 0.8 %, 1.2 % und 2.0 %) were implanted into the distal femur condylus of 18 New Zealand White Rabbits. They were placed into the spongy-cortical passage. During six weeks the animals were examined daily and x-rayed weekly. After euthanasia the bone was explanted and scanned in a microcomputed tomograph. The implants were well tolerated by the rabbits, neither lameness nor signs of pain occured. Wound healing was mostly without complications. Eight of 36 implants (22 %) showed dehiscence of suture within first ten days, whereby implants made of 1,2 % MgCa were mainly affected (six of 12 cases, 50 %). At the place of insertion all implants induced obvious callus genesis which could be seen in MgCa 1,2-cylinders with plane surface and MgCa 0,8-cylinders with rough and sand blasted surface the most. Influence of different calcium concentrations on degradation behaviour could not be discovered. They showed different stages of resorption. Concerning the different surface machining treatments sand blasted implants showed the highest degree of degradation which could be seen by the totally loss of structure in micro-computed examinations. These implants also showed in six of 36 cases a clinical occurrence of gas production. Rough implants showed an irregular degradation with high degree of resorption of some implants and signs of degradation only in the border area of others. Cylindricity maintained in plane implants. They showed loss of structure only in border areas.

Alloys↗
PubMed2005

Myxoma virus M128L is expressed as a cell surface CD47-like virulence factor that contributes to the downregulation of macrophage activation in vivo.

The M128L myxoma virus gene expresses a five-membrane spanning cell surface protein with significant amino acid homology to the cellular CD47 proteins. CD47, also called integrin-associated protein (IAP), is associated with the modulation of leukocyte adhesion, motility, activation, and phagocytosis. Creation of an M128L-deletion mutant myxoma virus strain and subsequent infection of the European rabbit demonstrated that M128L is necessary for the production of a lethal infection in susceptible rabbits, while it is fully dispensable for virus replication in vitro. Secondary sites of infection developed on the majority of rabbits infected with the M128L-deletion mutant (vMyx128KO), demonstrating that the M128L protein is nonessential for the dissemination of virus within the host. Although the size and severity of the primary lesions on vMyx128KO-infected rabbits were comparable to rabbits infected with the wild-type virus at the early stages of disease progression, by day 7 the reduced virulence of the vMyx128KO virus was clearly evident and all of the animals recovered from infection by the M128L-knockout virus. Histological analysis of the tissues of vMyx128KO-infected rabbits revealed greater activation of monocyte/macrophage cells in infected and/or lymphoid tissues when compared to those of wild-type myxoma-infected rabbits. We conclude that the M128L protein is a novel CD47-like immunomodulatory gene of myxoma virus required for full pathogenesis of the virus in the European rabbit and that its loss from the virus results in increased activation of monocyte/macrophage cells during infection.

Animals↗
PubMed2005

Childcare as a stabilizing influence on HPA axis functioning: a reevaluation of maternal occupational patterns and familial relations.

The influence of family relations, maternal occupational characteristics, and childcare1The UK terms "childcare," childcare centres' and "nurseries" are used throughout this paper to define group care for children prior to starting their first year of formal schooling at age 4 years and are used synonymously with the American terms "day-care" and "preschool." This form of group care is provided in a formal setting, outside the family home and excludes "childminding" (i.e., childcare that may be group based and offered at the home of the care provider/childminder). In the UK, this form of childcare is offered from zero to 4 years old. Children are separated according to their age into small groups usually consisting of 10-15 children. In the present study, all children were in the preschool-aged group (3-4 years old). Where childcare of a different or more generic form is referred to, then this has been made clear in the context or stated in the text. utilization on preschool children's cortisol production were investigated in 56 mother-child dyads. Family characteristics and maternal employment, childcare and child temperament were reported by mothers. Morning and evening levels of children's salivary cortisol were obtained. Children in highly expressive or reserved families exhibited higher cortisol levels compared to children in moderately expressive families. Elevated levels of cortisol were detected in children of mothers reporting low levels of job role quality or high levels of emotional exhaustion. Frequent childcare use was found to protect children against the physiological effects of low maternal job role quality and emotional exhaustion. Findings underscore the pervasive role of the family as set within an external support system and highlight the potential physiological impact of these interacting contexts for children. Further research is needed to fully understand current findings and to develop appropriate psycho-physiological interventions.

Adult↗
PubMed2004

Brain morphometry and IQ measurements in preterm children.

Although IQ is thought to remain relatively stable in the normal population, a decline in IQ has been noted in children born preterm. It is not clear, however, to what extent the inclusion of children with clear neurological damage has influenced these findings. We examined IQ scores obtained in childhood and then again in adolescence from a group of children born at 30 weeks gestation or less who had been classified as neurologically normal at 7.5-8 years. They showed a significant decline in mean IQ scores over time. MRI scans obtained from a subset of children at adolescence were read as normal in approximately 50% of cases and, in the others, there were no consistent relationships between radiological abnormalities and IQ results. Such children can, however, have relatively subtle brain abnormalities that are not seen on conventional MRI, and we hypothesized that these would be related to declines in IQ. Voxel-based morphometry (VBM) analyses of the MRI scans revealed that absolute IQ scores were related to areas in both the parietal and temporal lobes. The analyses also showed that frontal and temporal lobe regions were associated with the decline in VIQ, while occipital and temporal lobe regions (including the hippocampi) were associated with the decline in PIQ. Hippocampal volume measurements were consistent with the VBM findings. We concluded that preterm children are at risk of declining IQ over time even if they have not suffered obvious neurological damage and that the decline is associated with specific neural regions. Whether this is true of children born at >30 weeks gestation and what other factors predispose to this decline have yet to be determined.

Adolescent↗
PubMed2004

Antibody response and antigen-specific gamma-interferon profiles of vaccinated and unvaccinated pregnant sheep experimentally infected with Brucella melitensis.

It is well known that the immune response in sheep against Brucella melitensis is subject to individual variation, depending on diverse factors. It bears asking whether these factors (e.g. clinical disease, active infection, state of previous immunity), when affecting a group, can cause variation in the performance of different diagnostic tests. To clarify some of the circumstances in which this immune response can vary, we examine the immune-response profile of sheep protected against the clinical disease by prior vaccination with strain Rev. 1 in comparison with the profile of unprotected females showing the classical brucellosis symptoms. An experimental infection was provoked at midpregnancy under controlled conditions of both non-vaccinated (n=7) and previously Rev.1-vaccinated ewes (n=5). Their immune response was monitored from 7 to 9 weeks before abortion or normal birth to 30 weeks afterwards. Antibody response was assessed by classical tests (Rose Bengal test, complement fixation test (CFT)) in comparison with other diagnostic tests (indirect ELISA (iELISA), competitive ELISA (cELISA), fluorescence polarization assay (FPA), immunocapture test (ICT)). In addition, the cell-mediated immune response was indirectly evaluated by the in vitro antigen-specific release of gamma-interferon. The antibody levels and antigen-specific gamma-IFN profile of the non-vaccinated ewes having the disease and excreting the pathogen was notably high and differed significantly (P<0.05 or P<0.01) from those of vaccinated ewes that neither contracted brucellosis nor excreted the pathogen. In general, all the tests detect the infection in the non-vaccinated ewes with substantial effectiveness. It can be concluded that the high levels of circulating antibodies and of antigen-specific gamma-IFN are related to active Brucella infection. Similarly, the state of protection against the disease, but not necessarily against infection, due to a previous immunization with the Rev. 1 vaccination, appears to be responsible for a low level of detectable immune response. Nevertheless, the design of the study limits conclusions to pregnant ewes and cannot be extrapolated to non-pregnant ewes or rams. Likewise, the study provides no information on animals which are carriers of B. melitensis.

Animals↗
PubMed2004

Evaluation of two replacement regimens in primary adrenal insufficiency patients. effect on clinical symptoms, health-related quality of life and biochemical parameters.

OBJECTIVE: To evaluate clinical symptoms, health-related quality of life (HRQL) and biochemical parameters in patients with primary adrenal insufficiency under treatment with two different hydrocortisone regimens (20 mg-0 mg-10 mg/day and 10 mg-5 mg-5 mg/day), each maintained for 3 months and compare results obtained with those in healthy controls. DESIGN, PATIENTS AND METHODS: Twelve patients with primary adrenal insufficiency were studied. Clinical symptoms and HRQL with the Nottingham Health Profile (NHP) were evaluated and Na, K and serum cortisol determined at 09:00 h, 12:30 h and 17:30 h and urinary free cortisol (UFC) throughout the day. Control group comprised 19 healthy subjects. RESULTS: No differences in specific adrenal insufficiency symptoms were detected between the two regimens. HRQL was worse in energy dimension assessed by the NHP compared to the general population, regardless of 20 mg-0 mg-10 mg/day or 10 mg-5 mg-5 mg/day treatment (p=0.03 and p=0.013). The total NHP score was only adversely affected when patients were on the 10 mg-5 mg-5 mg/day hydrocortisone replacement regimen (p=0.008). Serum cortisol concentrations were higher than controls at 09:00 h, and lower at 17:30 h with both regimens, whereas serum cortisol at 12:30 h and UFC were within the 5th-95th percentile normal range only with the 10 mg-5 mg-5 mg/day regimen. CONCLUSIONS: Patients with primary adrenal insufficiency had worse HRQL in the NHP energy dimension compared with the general population, regardless of the hydrocortisone regimen although total score for HRQL was worse only with the 10 mg-5 mg-5 mg/day regimen. Patients on the thrice-daily hydrocortisone regimen showed a more physiological cortisol profile, leading us to recommend initially treating patients with this dose and increasing it in the case of impaired HRQL.

Addison Disease↗
PubMed2004

[Evaluation of the efficacy of CT guided thoracic sympatholysis to treat palmar hyperhidrosis].

PURPOSE AND METHOD: Palmar hyperhidrosis is a pathological condition characterized by overperspiration caused by any stress or emotion. We have evaluated the results of 101 CT guided sympatholysis procedures performed on 50 patients suffering from primary palmar hyperhydrosis. RESULTS: Mean follow up was 50 Months (6 Months to 8 Years) for 87 procedures with immediate good results in 46 patients. Using actuarial analysis, 62% of patients had persistent good results after 50 Months. Complications included one case of small pneumothorax requiring no treatment and one case of vagal syndrome. Pain or thoracic discomfort was reported by 14 patients and was relieved by aspirin within 24 hours. Six patients developed a Horner's syndrome that resolved within a few weeks and six other patients developed moderate compensatory overperspiration over the face, thorax or contralateral arm. CONCLUSION: Based on our results, CT guided sympatholysis provides results similar to endoscopic thoracic sympathectomy and is associated with fewer risks.

Adolescent↗
PubMed2004

Antibody response to the Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in healthy and infection-prone individuals with IgG3 subclass deficiency.

Searching for a possible explanation for the phenotypic heterogeneity in IgG3 deficiency, we studied the antibody response to a polysaccharide and a protein antigen in IgG3-deficient (IgG3d) adults after vaccination with Haemophilus influenzae type b capsular polysaccharide (Hib CP) conjugated to tetanus toxoid. Distribution of isotypes, idiotypes, clonotypes, and Gm allotypes were compared. All the vaccinated individuals, irrespective of the level of IgG3 and proneness to infections, developed protective levels of anti-Hib CP. Significantly lower prevaccination levels of IgG2 (p < 0.05) and IgG4 anti-Hib CP (p < 0.04 and p < 0.03) were noted among the infection-prone compared to the healthy IgG3d individuals and/or controls. Seventy percent of the IgG3d patients and none of the controls had the low responding Gm(ga-n/ga-n) genotype, while the majority of the controls had the alternative Gm(bfn/bfn) genotype. The conjugate ACT-HIB vaccine efficiently overcomes the IgG3 subclass deficiency state and the genetic predisposition for lower responsiveness, providing protection against Hib and tetanus infections. The proneness to infection in some IgG3d individuals may relate to their low prevaccination antibody levels.

Enzyme-Linked Immunosorbent Assay↗
PubMed2004

Number of days needed to assess energy and nutrient intake in infants and young children between 6 months and 2 years of age.

OBJECTIVE: To estimate the minimum number of days of recorded dietary intake needed to place infants and young children into thirds of a population distribution with an acceptable degree of accuracy. DESIGN: Dietary intake data collected from 5-day weighed food records for 72 infants and young children up to 2 y of age, collected during a cross-sectional study, were analysed to estimate the number of recording days necessary to assess intake of energy and 10 nutrients. SETTING: Community study among healthy infants and children. SUBJECTS: Parents attended recruitment sessions in local community areas. In total, 72 subjects were entered into the study and all completed the 5-day dietary assessment period. INTERVENTIONS: A 5-day weighed record of children's dietary intake was made by the parents or regular carer. RESULTS: Mean within subject standard deviations were smaller than mean between subject standard deviations with respect to energy (778 vs 824 kJ/day), macronutrient subclasses: protein (8 vs 9.4 g/day); fat (9 vs 10 g/day); and carbohydrate (26 vs 29 g/day) and for specific micronutrients: calcium (163 vs 236 mg/day); phosphorus (143 vs 270 mg/day); magnesium (25 vs 43 mg/day); iron (2 vs 3 mg/day); zinc (1 vs 1.3 mg/day); ascorbic acid (27 vs 64 mg/day) and retinol equivalents (281 vs 424 microg/day). Estimated number of days of food records necessary to assess intake of energy, protein, fat and carbohydrate with acceptable degree of accuracy were 5,4,4 and 3, respectively. For all the micronutrients included in this analysis 2 days of recording were necessary. CONCLUSION: Compared with adults and older children, fewer days are needed to classify this age group into thirds of the distribution with an acceptable degree of accuracy according to intake of energy and specific nutrients. SPONSORSHIP: The data collection phase of this study was supported by a grant from the Procter and Gamble Company, Cincinnati, OH, USA.

Age Factors↗
PubMed2004

Depth-map-based scene analysis for active navigation in virtual angioscopy.

This paper presents a new approach dealing with virtual exploratory navigation inside vascular structures. It is based on the notion of active vision in which only visual perception drives the motion of the virtual angioscope. The proposed fly-through approach does not require a premodeling of the volume dataset or an interactive control of the virtual sensor during the fly-through. Active navigation combines the on-line computation of the scene view and its analysis, to automatically define the three-dimensional sensor path. The navigation environment and the camera-like model are first sketched. The basic stages of the active navigation framework are then described: the virtual image computation (based on ray casting), the scene analysis process (using depth map), the navigation strategy, and the virtual path estimation. Experimental results obtained from phantom model and patient computed tomography data are finally reported.

Algorithms↗
PubMed2004

Does weaning influence growth and health up to 18 months?

BACKGROUND: National and international recommendations for the age of introducing solid foods (weaning) are founded on insufficient evidence and little is known about the short and medium term consequences associated with early or late weaning. AIMS AND METHODS: Data from over 1600 infants from five prospective randomised trials conducted in the UK between 1993 and 1997 were used to determine the influence of weaning < or =12 weeks or >12 weeks on growth and health outcomes (diarrhoea and vomiting, lower respiratory chest infections, atopy, sleep patterns) up to 18 months post-term, in term appropriate for gestational age (AGA), term small for gestational age (SGA), and preterm infants. RESULTS: Term infants weaned < or =12 weeks were heavier at 12 weeks of age than those weaned after 12 weeks, but showed slower gain in weight, length, and head circumference between 12 weeks and 18 months than those weaned after 12 weeks; by 18 months, there were no significant differences in size between the two groups. A similar pattern was seen in preterm infants. Breast fed term infants were more likely to be sleeping though the night at 9 months if they were weaned before 12 weeks. No weaning effects or interactions were observed for health outcomes. CONCLUSIONS: We found little evidence that weaning before or after 12 weeks influences health outcomes up to 18 months. Early weaned infants were larger at 12 weeks than later weaned infants but the growth trajectories of the two groups "converged" by 18 months. These findings do not exclude the later emergence of programmed effects of weaning practices.

Animals↗