Biomedical subjects

L Martens

Publications and source records attributed to L Martens.

At least 19 recordsLinked to original sources

PubMed2001

Protein identification based on matrix assisted laser desorption/ionization-post source decay-mass spectrometry.

Due to its very short analysis time, its high sensitivity and ease of automation, matrix-assisted laser desorption/ionization (MALDI)-peptide mass fingerprinting has become the preferred method for identifying proteins of which the sequences are available in databases. However, many protein samples cannot be unambiguously identified by exclusively using their peptide mass fingerprints (e.g., protein mixtures, heavily posttranslationally modified proteins and small proteins). In these cases, additional sequence information is needed and one of the obvious choices when working with MALDI-mass spectrometry (MS) is to choose for post source decay (PSD) analysis on selected peptides. This can be performed on the same sample which is used for peptide mass fingerprinting. Although in this type of peptide analysis, fragmentation yields are very low and PSD spectra are often very difficult to interpret manually, we here report upon our five years of experience with the use of PSD spectra for protein identification in sequence (protein or expressed sequence tag (EST)) databases. The combination of peptide mass fingerprinting and PSD and analysis described here generally leads to unambiguous protein identification in the amount of material range generally encountered in most proteome studies.

Peptide Fragments↗

PubMed2001

The psychological well-being of family members of individuals with schizophrenia.

BACKGROUND: The purpose of the study was to attempt to understand the experience of family members of individuals with schizophrenia. More specifically, we wanted to determine whether a measure of caregiving would be a stronger predictor of the psychological well-being of families who have a member with schizophrenia than a measure of burden. METHOD: Forty-one family members of 30 individuals with schizophrenia were recruited. A measure of burden, a measure of the experience of caregiving, and the duration of the illness were used to determine the best predictor of psychological wellbeing. RESULTS: Regression analyses indicated that the strongest predictor of psychological well-being was the negative scale of the Experience of Caregiving Inventory (ECI). There was also a significant relationship between poor psychological well-being and short duration of illness. CONCLUSIONS: The findings of the study indicated that family members are significantly distressed as a result of having a family member with schizophrenia. There is support for using newer scales, like the ECI. Furthermore, increased family support is required in the early stages of the illness.

Adult↗

PubMed2001

Assessing risk indicators for dental caries in the primary dentition.

The aim of the present study was to assess indicators shown to be associated with the prevalence of caries in the primary dentition of 7-year-old Flemish schoolchildren. Cross-sectional first year data of the longitudinal Signal-Tandmobiel survey were analysed (n=4468). Gender, age, oral hygiene habits, use of fluorides, dietary habits, geographical factors and parental modelling were the considered predictors. From the multiple logistic regression analysis, including schools as a random effect, and after adjusting for the confounding variables-educational system and province (stratification variables), gender and age-it became clear that the following risk indicators remained significant (at 5% level) for the presence of caries: frequency of toothbrushing (P=0.05) with an OR 1.24 for brushing less than once a day, age at start of brushing (P<0.001) with an OR=1.22 for a delay of 1 year, regular use of fluoride supplements (P<0.001) with an OR=1.54 for no use, daily use of sugar-containing drinks between meals (P<0.001) with an OR=1.38, and number of between-meals snacks (P=0.012) with an OR=1.22 for using more than 2 between-meal snacks. There was a significant difference (P<0.05) in caries experience determined by the geographical spread, with an explicit trend of caries declining from the east to the west. In a model with an ordinal response outcome, the daily use of sugar-containing drinks between meals had a more pronounced effect when caries levels were high. From this study it became obvious that, in Flemish children, an early start of brushing and a brushing frequency of at least once a day need to be encouraged, while the use of sugar-containing drinks and snacks between meals needs to be restricted to a maximum of 2 per day. Geographical differences need to be investigated in more detail.

Age Factors↗

PubMed2001

Caries prevalence in Belgian children: a review.

A review of epidemiological surveys on dental caries prevalence, published between 1980 and 1999 in Belgian children, was compiled through a literature search. The number of studies performed in Belgium to date is limited. Methodological differences and confounding factors, especially socio-demographic influences, limit national comparisons of caries prevalence data. Although exact comparisons are difficult, data suggests a decline in caries prevalence in 5, 7 and 12 year-old Belgian schoolchildren in the last 20 years. In the primary dentition dmft values have decreased from 2.66 (1981) to 1.38 (1994) in 5-year-olds and from 4.1 (1983) to 2.24 (1996) in 7-year-olds. In 12-year-olds DMFT values in the permanent dentition have decreased from 3.9 (1983) to 1.93 (1994). WHO goals for the year 2000 appear to have been already reached in Flanders, with a recent estimate of 1.93 for DMFT in 12-year-olds and 56% of children being recorded as caries free at the age of 5. Continuing efforts are needed to screen the oral health of different age groups but standardised criteria and sampling procedures should be used if benefits are to be gained from national and international comparison. Data has often been limited to small selected areas and information representing the entire community of Flanders or Wallonia would be of particular value.

Belgium↗

PubMed2001

[Analysis of dental caries risk factors in the primary dentition].

Belgium↗

PubMed2001

[Factors determining dental plaque and their relation to the assessment of caries among 7-year-old Flemish children].

The present investigation aimed to assess the impact of a number of variables on the variation on the amount of dental plaque present in the mixed dentition of 7-year-old Flemish children and to investigate a potential correlation between caries experience and the amount of dental plaque. Analyses were performed with ordinal plaque index as outcome measure, considering the children's school (i.e. class) as a random effect. This random effect turned out to be of great importance when dealing with large clustered samples. From the multiple logistic regression analysis, it was concluded that the older the subjects the more dental plaque was observed (or = 1.35; CI: 1.08-1.68; P = 0.0081). Four exploratory variables, could be identified as important risk indicators for dental plaque accumulation in the mixed dentition: 'start of brushing after the age of 2 years' (or = 1.161; CI: 1.09-1.23; P < 0.0001), 'brushing frequency of < 1 x/day (or = 1.37; CI: 1.12-1.66; P = 0.0019), more than two in between meal snacks (or = 1.18; CI: 1.03-1.36; P = 0.02) and daily intake of sugar containing drinks (or = 1.24; CI: 1.08-1.42; P = 0.002). Further, being male was linked to a higher amount of plaque (or = 1.16; CI: 1.00-1.34; P = 0.0506). Finally a weak but significant correlation (spearman's rho: r = 0.23; P < 0.0001) between caries experience and the amount of cervical plaque was shown.

Belgium↗

PubMed2001

[Fluorosis: diagnosis, risk assessment and epidemiology].

Fluorosis is the most widespread side-effect of fluoride use and appears as discrete white spots on the enamel up to severe enamel dysplasia. There are different techniques for scoring fluorosis in epidemiological surveys. In the literature there is no uniform way of selection of teeth and data processing. Fluorosis risk is determined by environmental factors such as water and food fluoride content as well as individual factors such as use (or misuse) of fluoride supplements and fluoridated oral hygiene products. In a group of Flemish schoolchildren, fluorosis prevalence is low and mainly related to use of fluoride supplements and toothpaste in childhood.

Belgium↗

PubMed2000

Oral hygiene in 12-year-old disabled children in Flanders, Belgium, related to manual dexterity.

As part of a larger epidemiological survey of a stratified sample of 12-year-old handicapped children in Flanders, Belgium, the present study describes gingival health, gingival hypertrophy, oral cleanliness and the presence of calculus. Statistical analysis was performed with motor skills, brushing help, the use of chemical agents, the use of anti-epileptic drugs, the knowledge of parents and educators (or caregivers) and their opinion of the oral hygiene of their children/ pupils as response variables. From this study, it became clear that mildly mentally retarded and learning-impaired children had significantly better manual dexterity skills than moderately and severely mentally retarded and physically impaired children. However, this was not reflected in improved oral hygiene. The use of chemical plaque controlling agents was found to be extremely low and, with the exception of children with gingival hyperplasia, the users of these agents did not have better oral hygiene. No difference was found between subtypes in the opinion of parents and educators on oral status. There was, however, a difference between their assessment and the clinical picture. It was concluded that there was a need for in-service training programmes in oral health care for educators as well as for parents.

Analysis of Variance↗

PubMed1999

Reliability of laser Doppler flowmetry in a 2-probe assessment of pulpal blood flow.

OBJECTIVE: The reliability of using 2 probes with laser Doppler signals when adjacent teeth are being measured simultaneously to determine pulpal blood flow is unknown. The purpose of this study was to determine whether 2 probes are more reliable than 1 in a single-tool assessment. STUDY DESIGN: Tooth pulp vitality was studied in 19 adults through use of laser Doppler flowmetry tests. In each subject, testing was carried out on 2 successive occasions with 2 probes positioned on the maxillary central incisors. RESULTS: Significant mean differences of 31% for blood flux and 96% for concentration were found between the 2 probes, although they shared equal coefficients of variation. The reproducibility for each probe was found to be consistent, and the probes were highly correlated with each other. Flux and concentration, however, were not systematically correlated. CONCLUSIONS: Simultaneous measurements with 2 probes were clearly more reliable. The necessity for a calibration control was evident.

Adult↗

PubMed1998

Major costs associated with pressure sores.

Cost drivers in the treatment of full-thickness pressure sores were identified from the literature, Medicare data tapes and interviews with health-care providers. The following were identified as cost drivers in pressure sore treatment: nursing time related to wound care; nursing time devoted to patient position changes; dressing products; patient support devices; antibiotics; room charges for nursing home care; doctor visits for nursing home and home care patients; surgical debridement for nursing home and home care patients; hospital admissions for medical treatment for pressure sores; admissions for surgical treatment for pressure sores; and additional costs for hospital stays when patients who are admitted for other diagnoses develop sores. These cost drivers may be useful to health-care providers in developing cost-effective strategies for treating and preventing pressure sores.

Bandages↗

PubMed1998

Linking postdoctoral general dentistry programs with managed care programs and settings.

This report presents the results of a small workgroup convened by the American Association of Dental Schools to examine experiences related to postdoctoral general dentistry programs linked with managed care systems and clinical settings. The workgroup was a component of an Association effort to identify and promote innovative and nontraditional methods by which the number of postdoctoral general dentistry (PGD) positions can be increased to meet current demand for PGD education. The participants identified factors and conditions that they believed to be critical to the planning, development, and conduct of PGD programs with substantial linkages with managed care systems and settings. The information should be helpful to others as they consider opportunities to establish PGD programs or increase their number of PGD training positions.

Academic Medical Centers↗

PubMed1997

Oral health condition of 12-year-old handicapped children in Flanders (Belgium).

The dental condition of 626 12-year-old handicapped children with mild mental or moderate to severe mental retardation or learning impairment, being 25% of the population of each of these groups, was examined in Flanders. An evaluation of oral cleanliness showed poor oral hygiene in 31.8% of the children. No significant differences were found in oral cleanliness among types of handicapping conditions. The mean DMFT score was 2.9 (s: 2.6) and DMFS score was 5.4 (s: 5.6). Almost 21% of the children were free of caries or fillings. No significant differences were found among groups of handicapped children. Handicapped children presented a low level of restorative care (restorative index score: 48.7%). Mildly mentally retarded children demonstrated the lowest restorative index (43.9%). The caries experience of first permanent molars represented the largest part of the DMFT score (64.1%). Sealants were present in 7.9% of children examined. A considerable percentage of mildly mentally retarded children and learning impaired children did not brush daily (22.1% and 20.9%) and did not receive help with toothbrushing from their parents or carers (91.0% and 94.7%, respectively).

Belgium↗

PubMed1997

[The use of chlorhexidine as a preventive and therapeutic means of plaque control in the handicapped. Review of the literature and definitive advise for application].

With respect to oral hygiene, most of the handicapped are very dependent. Moreover, it is shown that the higher the dexterity level, the poorer the oral hygiene. It's well documented that the use of Chlorhexidine (CHX) is an essential tool in oral care for the handicapped. The efficacy however, only becomes optimal after thorough plaque and calculus removal. From the literature, it becomes clear that the application of a 1% gel in prefabricated trays is the most efficient. Regarding mouthrinses, it's important to use big volumes in order to reach optimal contact with tooth surfaces. The use of a spray seems very handy but is quiet inefficient; no homogeneous diffusion of CHX can be obtained. The choice of any device for CHX application depends on the handicapping condition and on the knowledge and motivation of educators, and medical care takers. The present article summarizes the dental literature on the use of CHX in handicapped. An advice for well indicated use of CHX is proposed.

Aerosols↗

PubMed1997

[Dental care in autism].

The syndrome of autism is not characterized by typical orofacial features. Regarding caries experience, no differences with the normal population are found. The dental health situation on the other hand, depends upon the care devoted to oral hygiene and when necessary, upon the auxiliary help of parents and educators. As far as dental care is concerned, the autistic patient is inherently unresponsive to demonstrations, resists eye-to-eye contact and will frequently resist any effort to establish personal contacts with the dental personnel. Patient management will therefore be qualitatively different from person to person and shall be based on a unique management of the behavioral characteristics. Where the classical 'tell, show, do"-method fails, the 'tell, show, FEEL, do"-method will lead to a successful approach.

Anesthesia, Dental↗

PubMed1996

[Evaluation of long-term release of fluoride by type II glass ionomer cements with a conventional hardening reaction].

As a part of a fundamental investigation on the fluoride release of glass ionomer cements (GIC), this study investigates the operator dependency of the fluoride release. In this respect the GIC fluoride release of a classical powder-liquid based system (Fuji II) and a capsule-based system (Fuji Cap II) in water during 14 days was determined on the hand of 5 specimens per formulation, made by 5 different operators. The data reveal that the variance on the fluoride release as well as the mean fluoride release at a given time are independent of the operator for both Fuji II and Fuji Cap II. In order to derive fundamental factors affecting the GIC fluoride release, the long-term fluoride release of 10 conventional setting type II GIC is investigated. In this respect the fluoride release profiles (FRP) of each of 5 cylindrical specimens (d = 6 mm, h = 3 mm) of Fuji II (FP), Fuji Cap II (FC), Miracle Mix (MM), Chemfil II (CP), Chemfil II in caps. (CC), Chelon-Fil (CF), Ketac-Fil (KF), Shofu II (SH), Chelon-Silver (CS) and Ketac-Silver (KS) were determined. The specimens were made according to the manufacturer's instruction and equilibrated at 37 degrees C in 25 mL distilled water up to 140 days. The water was regularly renewed and the fluoride concentration [F] of the equilibrated solution determined. A Multivariate Data Analysis of the ¿[F]],t¿-profiles on the basis of Principal Component Analysis (PCA) reveals that the FRP can be classified into 4 distinct groups: ¿CS,KS,FP¿ - ¿FC,CC¿ - ¿CF,KF¿ and ¿MM¿, leaving SH and CP apart as unclassifiable. When the cumulative amount of fluoride released ([F]c) for each individual sample is calculated and fitted as a function of time, a regression analysis shows that [F]c is most adequately fitted (r > 0.99) by [F]c = [F]I/t + t1/2 + beta. Square root of t, indicating that 2 kinetic processes are responsible for the FRP. A comparison of the parameters of this equation ([F]I, t1/2 and beta) shows that the physicochemical rationale for this classification of the GIC conforms to differences in the kinetics of these processes. From the classification, it becomes apparent that different formulations can result in the same FRP.

Dental Caries↗

PubMed1996

[Evaluation of the long-term release of fluorides from type II glass ionomer cements with conventional setting reactions].

As a part of a fundamental investigation on the fluoride release of glass ionomer cements (GIC), this study investigates the operator dependency of the fluoride release. In this respect the GIC fluoride release of a classical powder-liquid based system (Fuji II) and a capsule-based system (Fuji Cap II) in water during 14 days was determined on the hand of 5 specimens per formulation, made by 5 different operators. The data reveal that the variance on the fluoride release as well as the mean fluoride release at a given time are independent of the operator for both Fuji II and Fuji Cap II. In order to derive fundamental factors affecting the GIC fluoride release, the long-term fluoride release of 10 conventional setting type II GIC is investigated. In this respect the fluoride release profiles (FRP) of each of 5 cylindrical specimens (d = 6 mm, h = 3 mm) of Fuji II (FP), Fuji Cap II (FC), Miracle Mix (MM), Chemfil II (CP), Chemfil II in caps. (CC), Chelon-Fil (CF), Ketac-Fil (KF), Shofu II (SH), Chelon-Silver (CS) and Ketac-Silver (KS) were determined. The specimens were made according to the manufacturer's instruction and equilibrated at 37 degrees C in 25 mL distilled water up to 140 days. The water was regularly renewed and the fluoride concentration [F] of the equilibrated solution determined. A Multivariate Data Analysis of the [[F], t]-profiles on the basis of Principal Component Analysis (PCA) reveals that the FRP can be classified into 4 distinct groups: [CS,KS,FP]-[FC,CC]-[CF,KF] and [MM], leaving SH and CP apart as unclassifiable. When the cumulative amount of fluoride released ([F]c) for each individual sample is calculated and fitted as a function of time, a regression analysis shows that [F]c is most adequately fitted (r > 0.99) by [F]c = [F]I/t+t1/2 + beta, square root of t, indicating that 2 kinetic processes are responsible for the FRP. A comparison of the parameters of this equation ([F]I, t1/2 and beta) shows that the physicochemical rationale for this classification of the GIC conforms to differences in the kinetics of these processes. From the classification, it becomes apparent that different formulations can result in the same FRP.

Capsules↗

PubMed1995

Magnetic field induced currents in a human head from use of portable appliances.

The induced currents in a model of the human head resulting from use of small hand-held appliances were computed. The source of the induced currents, i.e. the alternating (60 Hz) magnetic field was modelled as a magnetic dipole. The limits of applicability of this model are given. The model of the human head was obtained by translating MRI data into tissue conductivity data. Computations of the distribution of the induced currents were performed using the impedance method. The induced current density rapidly decreases with the distance from the appliance. The maximum, however, predictably is not at the surface, because of the geometry of the head. For typical appliances, the values of the maximum current densities are high as compared to those induced by a uniform magnetic field. Generalized graphs were obtained for the maximum induced current density normalized to the appliance magnetic moment, as a function of the distance from the appliance. These graphs are given for two representative locations of the appliance with respect to the head.

Electromagnetic Fields↗

PubMed1995

[Oral hygiene of handicapped subjects in Flanders].

As part of an epidemiology survey within the population of handicapped 12-year old in Flanders this article describes several parameters related to oral health. On the average, it became obvious that oral hygiene had to be seriously increased. The presence of plaque and calculus is very typical for types 1, 2, 4 and 8. In addition, it is most striking to conclude that groups where a maximum of self-handiness is expected, do not score any better. The application of chemical controlling agents and the use of fluoride supplements is found extremely low. Finally, a lack was found, with respect to adequate oral hygiene instructions. There is a real need for in-service training programs for educators as well as for parents.

Belgium↗