Biomedical subjects

C Grau

Publications and source records attributed to C Grau.

At least 19 recordsLinked to original sources

PubMed2006

Location of brain rhythms and their modulation by preparatory attention estimated by current density.

To test the hypothesis that there is a functional modulation of conventional EEG bands associated with preparatory attention, putative changes in the spontaneous brain rhythms and their associated cerebral sources were addressed. The goals of the present report were, first, to find the brain areas with maximal rhythmic activity before warning and imperative stimuli in a classic contingent negative variation (CNV) paradigm, and, second, to study the modulation of the EEG rhythms of these areas during the preparatory attention interval which precedes the S2 (imperative) stimulus. Trial by trial LORETA analysis found similar brain rhythm generators during both pre-S1 and pre-S2 intervals. Each theta, alpha and beta traditional EEG rhythm originates in several anatomically distinct brain structures. Preparatory attention is associated with a decrease in power in alpha (right and left occipital and temporal areas) and low-beta (left frontal, bilateral occipital and middle frontal areas) EEG bands. In these structures power changes associated with preparatory attention modulated either a dominant or a non-dominant oscillatory band, suggesting that non-dominant rhythms of a cerebral area have some functional relevance. Our results imply distributed regional sources for brain rhythms and support the view that during preparatory attention there is a modulation of the brain sources generating alpha and beta brain rhythms. Moreover, the proposed combined approach makes it possible to explore the definition of a given brain area not only anatomically, but also by the frequency content and the functional reactivity of the electrical rhythms that it generates.

Adolescent↗

PubMed2006

Modulation of spectral power and of phase resetting of EEG contributes differentially to the generation of auditory event-related potentials.

Nowadays, the mechanisms involved in the genesis of event-related potentials (ERPs) are a matter of debate among neuroscientists. Specifically, the debate lies in whether ERPs arise due to the contribution of a fixed-polarity and fixed-latency superimposed neuronal activity to background electroencephalographic oscillations (evoked model) and/or due to a partial phase synchronization of the ongoing EEG (oscillatory model). The participation of the two mechanisms can be explored by the spectral power modulation and phase coherence of scalp EEG rhythms, respectively. However, an important limitation underlies their measurement: the fact that an added neural activity will be relatively phase-locked to stimulus, thus enhancing both spectral power and phase synchrony measures and making the contribution of each mechanism less clear-cut. This would not be relevant in the case that an increase in phase concentration was not accompanied by any concurrent spectral power modulation, thus opening the way to an oscillatory-based explanation. We computed event-related spectral power modulations and phase coherence to an auditory repeated-stimulus presentation paradigm with tone intensity far from threshold (90 dB SPL), in which N1 decreases its amplitude (N1 gating) as an attenuation brain process. Our data indicate that evoked and oscillatory activity could contribute together to the non-attenuated N1, while N1 to repeated stimuli could be explained by partial phase concentration of scalp EEG activity without concurrent power increase. Therefore, our results show that both increased spectral power and partial phase resetting contribute differentially to different ERPs. Moreover, they show that certain ERPs could arise through reorganization of the phase of ongoing scalp EEG activity only.

Acoustic Stimulation↗

PubMed2005

Combined ICA-LORETA analysis of mismatch negativity.

A major challenge for neuroscience is to map accurately the spatiotemporal patterns of activity of the large neuronal populations that are believed to underlie computing in the human brain. To study a specific example, we selected the mismatch negativity (MMN) brain wave (an event-related potential, ERP) because it gives an electrophysiological index of a "primitive intelligence" capable of detecting changes, even abstract ones, in a regular auditory pattern. ERPs have a temporal resolution of milliseconds but appear to result from mixed neuronal contributions whose spatial location is not fully understood. Thus, it is important to separate these sources in space and time. To tackle this problem, a two-step approach was designed combining the independent component analysis (ICA) and low-resolution tomography (LORETA) algorithms. Here we implement this approach to analyze the subsecond spatiotemporal dynamics of MMN cerebral sources using trial-by-trial experimental data. We show evidence that a cerebral computation mechanism underlies MMN. This mechanism is mediated by the orchestrated activity of several spatially distributed brain sources located in the temporal, frontal, and parietal areas, which activate at distinct time intervals and are grouped in six main statistically independent components.

Adult↗

PubMed2004

[Degree of understanding, treatment and control of hypertension, hypercholesterolemia and diabetes mellitus in the general adult population].

OBJECTIVES: To calculate the prevalence of the main cardiovascular risk factors (CVRF) after diagnostic confirmation using clinical criteria. To analyse the degree of understanding and monitoring of these factors and to evaluate the association of CVRF with each other, so estimating who is susceptible to intervention. DESIGN: Cross-sectional, descriptive, observational study. SETTING: Population study conducted in Health Area 20 of the Community of Valencia (county of the Low Plain of the River Segura). PATIENTS: People who had lived in this Area for >=20 years. Proportional, multi-stage randomised sampling with definition of sample quotas according to type of residence. SAMPLE SIZE: 2550 people (no reply in first stage: 26%). The second stage involved the clinical confirmation of those identified as suffering from hypertension (HT) (374), hypercholesterolaemia (HCOL) (126), and diabetes (DM) (33). MEASUREMENTS: Patients identified were interviewed for taking blood pressure in the case of those with HT, and blood samples in the case of those with HCOL and DM. The diagnostic criteria recommended by the latest consensus were used. RESULTS: 1886 people (78.1%) took part. Prevalences found: total HT 42+/-2.2%, diagnosed: 11.7+/-1.4; total HCOL 26.6+/-2%; total DM 9.5+/-1.3%. Tobacco dependency was 33.6+/-2.1% and Obesity: 31.6+/-2.1%. Degree of control: HT, 8.6%; HCOL, 21.7%; DM, 56.1%. Association of CVR factors with each other: 25.5% had neither HT nor HCOL and did not smoke. CONCLUSIONS: High prevalence of CVRF in our area, compared with published national findings. Tobacco dependency is less common than at national level. The degree of control is very low and the association of the main CVRF factors for ischaemic cardiopathy reflect that nearly 75% of the population requires a preventive intervention.

Adult↗

PubMed2003

Preparatory visuo-motor cortical network of the contingent negative variation estimated by current density.

The present report studied the intracerebral current density of the contingent negative variation (CNV) during a visuo-manual task using the gap paradigm. The CNV is usually obtained during preparatory periods for perception and action. In this experiment right-hand responses were required. The CNV potential was obtained during the preparatory period from electrodes placed at 58 scalp sites. The CNV showed an early and a late phase. Scalp voltage and source current density maps showed that the early phase was focused on frontal midline sites. The late phase had two foci, one overlying the primary motor cortex and one over occipital sites. When analyzed by low-resolution tomography, the early phase of the CNV showed activations in the supplementary motor area (SMA), the anterior cingulate cortex (ACC), and some posterior areas. The late phase had anterior activations in the left prefrontal cortex, middle frontal cortex, primary motor cortex, ACC, and SMA; and several posterior activations including those in the medial occipital cortex, middle inferior occipital cortex, posterior cingulate cortex, and temporal and parietal areas. Results from the activated areas and their temporal dynamics during the preparatory period suggest that the ACC and the SMA areas recruit the action- and perception-related areas needed to process the expected subsequent imperative task.

Adolescent↗

PubMed2003

Positive margins in basal cell carcinoma: relationship to clinical features and recurrence risk. A retrospective study of 248 patients.

BACKGROUND: Incomplete resection of a basal cell carcinoma does not necessarily imply tumour recurrence. OBJECTIVE: The purpose of our study was to determine the clinical features most often associated with positive surgical margins and to establish whether positive margins effectively imply tumour recurrence. METHODS: We did a retrospective evaluation of 273 basal cell carcinomas in a total of 248 subjects. For each case, data regarding tumour location, sex, histological type and the presence or absence of affected surgical margins were collected. Follow-up was available in 151 cases. RESULTS: Positive margins were most often observed in facial lesions, particularly in the nasal and perioral areas, and for morphoeic histological types. Tumours with margin involvement exhibited a higher recurrence rate (26%) than those with free margins (14%) over a 5-year follow-up period. CONCLUSIONS: Individualized management, with special considerations depending on tumour location and histological type, is needed to treat basal cell carcinomas and cases with affected margins. Re-excision, preferably with Mohs' surgery, is advised in the latter as recurrences are much more complicated to treat. Furthermore, all cases need adequate follow-up, even in cases with unaffected surgical margins.

Adult↗

PubMed2003

A simple method to test if the internal mammary lymph nodes are covered by the wide tangent technique in radiotherapy for high-risk breast cancer.

AIM: It is often complicated to include the internal mammary lymph nodes in the radiation field after breast-conserving therapy. Using the wide tangent technique the internal mammary lymph nodes are generally presumed to be included if the medial tangential field border is placed 3 cm across the midline. The current study was designed to test the validity of this assumption, and if possible, to correct the wide tangents without using computed tomography (CT) scanning. PATIENTS AND METHODS: Twenty-one consecutive, high-risk, post-lumpectomy patients were included. An arrangement of three copper wires was mounted in wax placed perpendicular to the skin surface at the ipsilateral border of sternum at intercostal spaces 2 to 4. During a standard simulation for wide tangents, it was examined if the length of the copper wires projected beneath the skin surface (representing the depth of the internal mammary lymph nodes, measured by ultrasound) were included in the wide tangent fields. RESULTS: In only one patient were the internal mammary lymph nodes covered by the wide tangent technique. In 14 of the remaining 20 patients the lateral tangential field border was subsequently moved in the posterior direction, and the internal mammary lymph nodes could be included without unacceptable normal tissue involvement. In the last six patients the irradiated heart and lung volumes exceeded acceptable tolerance levels with this correction, and these patients were referred for three-dimensional CT dose planning. CONCLUSION: The presented simple technique may be helpful if CT scanning is not available. In all other cases CT-based dose plan should ideally be used as a standard in the planning of radiotherapy after breast-conserving surgery to assure optimal inclusion of the relevant target, and to avoid irradiation of large volumes of critical normal tissue.

Adult↗

PubMed2002

An investigation of the repeatability and reproducibility of ISO 11948-1 (the Rothwell method) for measuring the absorption capacity of incontinence pads.

The repeatability and reproducibility (precision within and between laboratories, respectively) of an international standard method (ISO 11948-1, the Rothwell method) for measuring the absorption capacity of incontinence pads was investigated. The 74 shaped disposable bodyworn insert pads for heavy incontinence on the UK market in spring 1997 were tested in three laboratories experienced in using the method, one in each of England, Spain and Sweden. Coefficients of variation (standard deviation as a proportion of the mean) for five repeats rarely exceeded 5% within any laboratory. However, there were systematic differences between laboratories: results from the Swedish and Spanish laboratories typically exceeded those from the English laboratory by 13% and 8%, respectively. The good repeatability suggests that the method is capable of adequate precision but the poor reproducibility implies that the instructions in the standard for building and/or using the test apparatus are inadequate, leaving too much room for interpretation. Having studied the data presented here and viewed videos of the apparatus in use in five laboratories (including the three contributing to this note) the ISO working group which wrote the original standard has identified several likely sources of imprecision and is now working to revise the standard to improve its reproducibility.

England↗

PubMed2002

Comparison of two T-classification systems for sino-nasal carcinoma.

It is often difficult to determine the actual site of origin of tumours originating in the sino-nasal region, and a uniform classification system that covers all tumours in this area is warranted. A retrospective series of 165 consecutive patients with sino-nasal carcinoma, treated and followed at the Aarhus University Hospital between 1963 and 1991, was evaluated and T-staged according to the Lederman classification. The 80 maxillary antrum carcinomas were also staged according to the UICC 1997 system. In univariate analysis, the UICC T-classification was prognostic for locoregional tumour control and disease-specific survival. However, when adjusted for covariates (gender and nodal involvement) in a multivariate analysis, the UICC classification was not a significant independent prognostic parameter. In contrast, the Lederman T-classification was prognostic both in univariate and multivariate analysis. The Lederman T-classification was more prognostic for locoregional control and disease-specific survival than the UICC TNM classification. In addition, the Lederman classification is easy to use and has a broader applicability as it covers all sites in the sino-nasal area.

Adenocarcinoma↗

PubMed2001

[New therapeutic perspectives in breast ductal carcinoma in situ].

Management of ductal carcinoma in situ (DCIS) of the breast has suffered from a lack of consensus. The results of recent studies may create the basis for a more rational treatment strategy. Surgical treatment of DCIS with mastectomy is curative, but often unnecessary. Excision, in contrast, carries a recurrence risk of 10-63%, and the recurrence is invasive in half the patients. Two large studies have shown that irradiation after breast conservation reduces the recurrence risk to almost half. Thus, adjuvant radiotherapy should, in principle, be offered. Retrospective analyses indicate, however, that patients having tumours removed with a > 10 mm free margin or with small, low-grade tumours may be considered to be adequately treated by surgery alone. A recent study showed that adjuvant antihormone therapy further reduces the risk of recurrence. The absolute benefit seems low, however, and additional investigations are required.

Breast Neoplasms↗

PubMed2001

[Cervical lymphatic metastases from occult primary tumor. A nation-wide 20-year study from the Danish society of head and neck oncology].

INTRODUCTION: The management of patients with cervical lymph node metastases from unknown primary tumours is a major challenge in oncology. This study presents data collected from all five oncology centres in Denmark. MATERIALS AND METHODS: Of the 352 consecutive patients with squamous cell or undifferentiated tumours seen from 1975 to 1995, a total of 277 (79%) were treated with radical intent. Most patients received radiotherapy to both sides of the neck as well as elective irradiation of the mucosal sites in nasopharynx, oropharynx, hypopharynx and larynx (81%). Irradiation of the ipsilateral neck only was done in 26 patients (10%). Radical surgery was the only treatment in 23 N1-N2 patients (9%). RESULTS: The five-year estimates of neck control, disease-specific survival and overall survival for radically treated patients were 51%, 48% and 36%, respectively. The emergence of the occult primary was observed in 66 patients (19%). About half of the emerging primaries were within the head and neck region with oropharynx, hypopharynx and oral cavity being the most common sites. Emerging primaries outside the head and neck region were primarily located in the lung (19 patients) and oesophagus (five patients). The most important factor for neck control was nodal stage (5-year estimates 69% [N1], 58% [N2] and 30% [N3]). Other important parameters for neck control and disease-specific survival included haemoglobin, gender and overall treatment time. Patients treated with ipsilateral radiotherapy had a relative risk of recurrence in the head and neck region of 1.9 compared to patients treated at both neck and mucosa. At five years, the estimated control rates were 27% (ipsilateral) and 51% (bilateral; p = 0.05). The 5-year disease-specific survival estimates were 28% and 45%, respectively (p = 0.10). DISCUSSION: Extensive irradiation to both sides of the neck and the mucosa in the entire pharyngeal axis and larynx resulted in significantly fewer loco-regional failures compared to patients treated with ipsilateral techniques, but only a trend towards better survival. Determination of the optimal strategy in terms of loco-regional control, survival and morbidity requires a prospective randomized trial.

Adolescent↗

PubMed2001

Auditory sensory memory as indicated by mismatch negativity in chronic alcoholism.

OBJECTIVES: A pre-conscious auditory sensory (echoic) memory of about 10 s duration can be studied with the event-related brain potential mismatch negativity (MMN). Previous work indicates that this memory is preserved in abstinent chronic alcoholics for a duration of up to 2 s. The authors' aim was to determine the integrity of auditory sensory memory as indexed by MMN in chronic alcoholism, when this memory has to be functionally active for a longer period of time. METHODS: The presence of MMN for stimuli that differ in duration was tested at memory probe intervals (MPIs) of 0.4 and 5.0 s in 17 abstinent chronic alcoholic patients and in 17 healthy age-matched control subjects. RESULTS: MMN was similar in alcoholics and controls when the MPI was 0.4 s, whereas MMN could not be observed in the patients when the MPI was increased to 5.0 s. CONCLUSIONS: These results provide evidence of an impairment of auditory sensory memory in abstinent chronic alcoholics, whereas the automatic stimulus-change detector mechanism, involved in MMN generation, is preserved.

Adult↗

PubMed2001

Randomized trial of opioids versus tricyclic antidepressants for radiation-induced mucositis pain in head and neck cancer.

Patients who receive radiotherapy for head and neck cancer are likely to develop painful mucositis. The pain is characterized by a burning or stinging sensation similar to neuropathic pain sensations. The purpose of the present study was to compare the analgesic effect of a tricyclic antidepressant (TC), commonly used in the treatment of neuropathic pain, with the effect of opioids on radiation-induced mucositis pain. Forty-three patients receiving 66-68 Gy external radiation according to the DAHANCA guidelines (the Danish Head and Neck Cancer Study Group) were randomized to either morphine or TC when mucositis pain was insufficiently managed with weak analgesics. Patients with insufficient pain control in either treatment arm received supplementary medication from the opposite treatment arm. Pain was evaluated weekly using a VAS scale and the McGill Pain Questionnaire. The degree of mucositis and the degree of depression were measured at the same time intervals. Twenty-two patients entered the opioid arm and 21 the TC arm. Two patients in each arm were non-evaluable. VAS pain scores were significantly reduced in the opioid treatment arm one week after randomization (p = 0.01). Eight patients in the TC arm were managed with TC alone, but for 11 patients it was necessary to add morphine. The 20 evaluable patients in the morphine arm required no additional treatment. There were no significant differences in side effects between the two groups. Higher pain scores in the TC arm, but not in the opioid arm, were significantly correlated with higher BDI scores. Some head and neck cancer patients with radiation-induced nucositis pain may have sufficient pain control on TC alone. This might be useful in patients with relative counter-indications to opioid treatment.

Aged↗

PubMed2001

Squamous cell carcinoma of the nasopharynx--an analysis of treatment results in 149 consecutive patients.

The purpose of this study was to evaluate the outcome of primary treatment and treatment of recurrences in patients with nasopharyngeal carcinoma. The material included 149 consecutive patients seen at the Aarhus University Hospital from 1963 to 1991 (49 females and 100 males). The stage distribution was: Stage I-9%, II-3%, III-28%, and IV-60%. Primary treatment was delivered with curative intent in 145 patients (97%). Persistent or recurrent disease after primary radical treatment was observed in 82 of the patients; 54% at the T-level, 40% at the N-level, and 33% at the M-level. A curative salvage attempt was carried out in 14 patients only, all with nodal recurrence: surgery in 8 patients (4 controlled) and radiotherapy in 6 patients (2 controlled). The 5-year local tumour control, locoregional tumour control, disease-specific survival rate and the overall survival rate for the patients treated with curative intent were 66%, 53%, 50% and 43%, respectively. Most of the patients (88%) had poorly differentiated tumours and these patients had the best prognosis. A major complication in three patients was radiation-induced myelopathy due to high-dose radiation delivered to the brain stem. Significant positive prognostic factors for treatment outcome in univariate analyses were early T-classification, small clinical stage, poor differentiation and low age. The Cox multivariate analysis showed that early T-categories, low N-categories and poor differentiation were independent, positive prognostic factors. Nasopharyngeal carcinoma is curable with primary radiotherapy; patients with poorly differentiated tumours have the best prognosis. Only a few patients were salvaged after recurrence. The factor most essential for success is primary control of the disease at the T- and N-levels.

Adolescent↗

PubMed2001

Sino-nasal cancer in Denmark 1982-1991--a nationwide survey.

Cancer of the nasal cavity and paranasal sinuses is a rare disease. The many different histologies and sites make the management of this disease a challenge. The current report from the Danish Society for Head and Neck Oncology comprises a joint analysis of five retrospective series covering the entire country, with 315 patients seen in the 10-year period from 1 January 1982 to 31 December 1991. Tumour sites were nasal cavity (n = 156), maxillary sinus (n = 139), ethmoid sinus (n = 14), sphenoid sinus (n = 5) and frontal sinus (one case). The most common histologies included squamous cell carcinoma (126 cases), adenocarcinoma (41 cases), malignant melanoma (38 cases) and malignant lymphoma (34 cases). A total of 284 patients (90%) received treatment with curative intent; most of these patients were treated with radiotherapy, either alone (120 patients) or in combination with surgery (111 patients). There was no significant difference between the five centres in disease specific survival and overall survival. The results showed that histology, localization and nodal involvement were significant prognostic factors for locoregional control and survival. Patients with squamous cell carcinoma had a significantly poorer prognosis compared with patients with adenocarcinoma. However, a Cox multivariate analysis revealed that this was likely the result of tumour localization, as most adenocarcinomas were in the nasal cavity. The experience from this data collection has inspired the Danish Society for Head and Neck Oncology to arrange common data registration of several other clinical head and neck series. In the future, the Society plans to expand this activity further.

Adolescent↗

PubMed2001

The H1-receptor antagonist dextro-chlorpheniramine impairs selective auditory attention in the absence of subjective awareness of this impairment.

Although previous studies have shown that the human attention system is partially affected by chlorpheniramine, the effects of chlorpheniramine on human auditory selective attention have not yet been explored. This study examines the effects of a single dose of 4 mg of dextro-chlorpheniramine on human auditory selective attention by means of the evaluation of the event-related brain potential (ERP) processing negativity (PN). The study sample consisted of 20 healthy male humans, who received either a single 4-mg dose of dextro-chlorpheniramine or a placebo in a double-blind design. The subjects were given a dichotic listening task, in which they were instructed to press a response button upon detecting deviant tones (target) while their ERPs were recorded. In parallel, subjective tests evaluated the daytime sleepiness, overall vigor, and affect of the subjects. Results showed that the auditory selective attention is impaired under the effects of chlorpheniramine, as reflected by an attenuation of PN amplitude and by a decrease of performance in the group of subjects who took a single 4-mg dose of dextro-chlorpheniramine. No subjective change in the daytime sleepiness, overall vigor, or affect of the subjects was observed. This lack of conscious awareness of the side effects may lead to situations of risk in tasks for which auditory information is important, because no subjective indicators of attention impairment are available to the subjects.

Adult↗

PubMed2001

Cutaneous infection caused by Aspergillus ustus, an emerging opportunistic fungus in immunosuppressed patients.

We report a case of primary cutaneous infection by the emerging fungus Aspergillus ustus in an immunosuppressed patient after a domestic accident. The patient failed to respond to itraconazole and died before receiving a new treatment with amphotericin B. There have been eight other cases reported since 1973, and only two patients survived the infection. In vitro susceptibility testing of seven antifungal drugs showed that terbinafine and the new azole derivative UR-9825 were the most active against this fungus.

Aged↗

PubMed2000

A decision analysis of the effect of avoiding axillary lymph node dissection in low risk women with invasive breast carcinoma.

BACKGROUND: Evidence that avoiding axillary lymph node dissection (AxD) strikes an appropriate balance between morbidity and recurrence risk in patients with invasive breast carcinoma generally is anecdotal and without a formally quantified basis. The current study presents a decision analysis of the difference in 5-year disease free survival (DFS) rate between treatment scenarios with and without routine AxD. METHODS: To derive quantitative estimates of the effect of avoiding AxD on 5-year DFS, the authors examined outcomes for women undergoing 2 treatment scenarios: AxD or no AxD with adjuvant therapy decisions based on risk factors in the primary tumor. Eligible patients belonged to 2 lymph node metastases risk groups: low (patients without palpable lymph nodes and lymphatic or vascular invasion [LVI] negative tumors < or = 0.5 cm in greatest dimension) and moderate (patients with mammographically detected, LVI negative tumors, between 0.6-2.0 cm in greatest dimension or patients with palpable LVI negative tumors between 0.6-1.0 cm in greatest dimension with nonpalpable lymph nodes). Along with observed data regarding treatment and recurrence, the authors employed estimates of the efficacy of chemotherapy, tamoxifen, and regional radiation therapy derived from published randomized trials to estimate the 5-year DFS rate for treatment scenarios with and without AxD. RESULTS: Patients in the low risk group had a 5% risk of lymph node metastases. In these women, eliminating AxD and treating no patients with chemotherapy and/or tamoxifen resulted in a < 1% decrease in the 5-year DFS rate. Patients in the moderate risk group had a 10% risk of lymph node metastases. Eliminating AxD and treating only those women with Grade 3 tumors > 1 cm in greatest dimension with chemotherapy and/or tamoxifen resulted in a 1.8% decrease in the 5-year DFS rate. However, if all patients in this group were treated with chemotherapy and/or tamoxifen and no AxD, the 5-year DFS rate increased by 2.7%. CONCLUSIONS: In patients with a low risk of lymph node metastases, it was estimated that eliminating AxD may result in only minimal changes in the estimated 5-year DFS rate.

Adult↗