Biomedical subjects

A Holst

Publications and source records attributed to A Holst.

At least 19 recordsLinked to original sources

PubMed2006

Signs and symptoms from ectodermal organs in young Swedish individuals with oligodontia.

OBJECTIVES: The aim was to assess signs and symptoms from other ectodermal organs in addition to teeth in young individuals with oligodontia and to establish the prevalence of oligodontia. SAMPLE AND METHODS: Children born 1981-94 reported by dental teams in the Public Dental Service to have oligodontia were asked to participate in a clinical study. The examinations comprised a structured interview on symptoms from ectodermal organs, and testing of salivary secretion. RESULTS: One hundred and sixty-two individuals met the inclusion criteria, and 123 individuals (75.9%) participated in the clinical study. Half of the individuals had one to four signs or symptoms from ectodermal organs beside oligodontia. The most common sign was low salivary secretion. Twelve individuals (9.6%) with isolated oligodontia reported impaired function of the sweat glands, hair, or nails. The prevalence of oligodontia was 0.090%. CONCLUSIONS: An early identification of individuals with oligodontia can be made in a majority of cases by checking that all permanent incisors have erupted at the age of 8 years. The validity in asking individuals about normal and abnormal function of ectodermal organs was found to be low. This indicates that there is a strong need to establish routine clinical criteria for dysplasia of ectodermal organs.

Adolescent↗

PubMed1999

Occurrence and distribution of caries in 6-year-old children in Blekinge, Sweden.

Community dentistry in Blekinge aims at age-specific levels of dental health. For 6-year-old children the goal is that > 65 percent will have dmft = 0 in the year 2000. At present there is no study on dental health in 6-year-olds in Blekinge. The aims of the present study are to establish baseline epidemiological data on dental caries in the county of Blekinge, expressed as dentin lesions and enamel lesions, to analyse these data and to formulate program oriented planning of dental care for pre-school children to achieve the dental health goal for the year 2000. The material comprised a random sample of 213 children. The sample was drawn from the population register for children living in the county of Blekinge. A clinical investigation was performed by one of the authors and was completed with bite-wing radiographs whenever the proximal surface could not be inspected clinically. In addition the parents were asked questions about tooth-brushing and use of fluoride tablets. Fifty-six percent of the children had filled lesions and manifest lesions (dfs), 65 percent had enamel caries lesions (dsi) and 42 percent had manifest lesions (ds). Fifty-three percent had dmft > 0. The finding of initial lesions in 65 percent of the children indicates that caries prevalence is greatly underestimated. Together with poor oral hygiene, this means an increase in the risk of caries progression. The pattern of dental health was very skewed among the children; 23 percent had between 5 and fourteen decayed or filled teeth and 11 percent had from 5 to 23 manifest lesions. Clinics in Blekinge have had different strategies for preventive dental care. In 1997, however, all the public dental service clinics in Blekinge, adopted a uniform program for child dental care, focusing on primary prevention and risk assessment for each individual.

Cariostatic Agents↗

PubMed1998

Evaluation of a 3-piece silicone intraocular lens with poly(methyl methacrylate) haptics.

PURPOSE: To evaluate the safety and performance of a foldable silicone intraocular lens (IOL) in small incision phacoemulsification surgery. SETTING: Vaasa Central Hospital, Vaasa, Finland. METHODS: Phacoemulsification with primary implantation of a posterior chamber IOL was performed in 50 patients. All eyes were implanted with a CeeOn IOL (model 920, Pharmacia & Upjohn) with a silicone optic and poly(methyl methacrylate) haptics. The ease of folding, implanting, and unfolding the IOL in the bag were recorded. Visual acuity, postoperative complications, optic decentration, and optic tilt were measured at 5 postoperative visits. The IOLs were evaluated for haze and discoloration and the IOL surface, for inflammatory or pigment deposits. Follow-up was 12 months. RESULTS: In 44 of 50 cases, folding the IOL was easy, and in 46 of 50, unfolding the IOL was controlled. The mean follow-up was 11.45 months +/- 0.52 (SD). No postoperative complications occurred, and 96% of patients achieved a best corrected visual acuity (BCVA) of 0.5 or better and 56%, a BCVA of 1.0 or better. The IOL decentration was less than 0.25 mm in 89% of cases, and there was no optic tilt. The neodymium:YAG laser capsulotomy rate was 11%. CONCLUSION: Good visual outcome and excellent centration were achieved with the CeeOn model 920 IOL. It is therefore suitable for small incision cataract surgery. Because of the IOL's smooth, polished surface, the choice of instruments for folding and implantation is important.

Aged↗

PubMed1998

Restoration of small proximal dentin lesions with the tunnel technique. A 3-year clinical study performed in Public Dental Service clinics.

The aim of this study was to evaluate the 3-year performance of tunnel restorations in Public Dental Service clinics in the county of Blekinge, Sweden. The restorations were made at the indication of a radiographically observed small proximal caries lesion extending into the outer part of dentin in permanent premolars and molars. A total of 302 restorations made by 17 dentists were evaluated 1 yr, 2 yrs and 3 yrs after placement using modified USPHS criteria. The preparations were filled with a cermet glass polyalkenoate cement (Ketac Silver, ESPE Gmbh, Germany). Evaluation was carried out by clinical and radiographical means. The percentage of successful and acceptable restorations was 92.7% after 1 yr, 89.5% after 2 yrs and 84.3% after 3 yrs. Eight % of the restorations failed due to caries, 6% fractured and 1% were replaced due to deep margin discoloration. The results indicate that tunnel restoration is a useful technique in small proximal dentin lesions in permanent premolars and molars.

Adolescent↗

PubMed1998

A five-year evaluation of fissure sealants applied by dental assistants.

The aim of this study was to evaluate if sealings of fissures is a preventive method appropriate for delegation to auxiliary personnel. After a two-day course, giving theoretical as well as practical knowledge, 77 dental assistants working at twelve dental clinics, sealed 3218 first and second permanent molars in children. The material used was the light-cured resin Delton Opaque. The sealings were examined once a year by the childrens ordinary dentists, using internationally accepted criteria. The result showed a total retention rate of 91% after one year and 69% after five. There were differences in success rate between the clinics, the majority demonstrating a five-year total retention rate between 70 and 94%. It was evident that the retention of sealings was influenced by the age of the children but not by the position of teeth in the mouth. The main part of failures appeared during the first year (35%) and failures were essentially due to fractures (64%). Eight percent of all teeth present at the end of the five-year period had become carious. The dental assistants sealed the fissures without any assistance and none of them had any previous experience of fissure sealings. In our opinion, sealing of fissures is a method well suited for delegation to dental assistants after proper education but should be followed up, as the success rate showed a great variation.

Child↗

PubMed1997

Onset of CNTFRalpha expression and signal transduction during neurogenesis in chick sensory dorsal root ganglia.

The expression of ciliary neurotrophic factor receptor alpha (CNTFRalpha) was investigated in the developing chick dorsal root ganglion (DRG) using affinity-purified anti-CNTFRalpha antibodies. At thoracic levels, CNTFRalpha-immunoreactivity (CNTFRalpha-IR) was first observed at stage 19 (E3) in cells with neuronal morphology. CNTFRalpha-IR is restricted to the neuronal lineage in the DRG throughout development. CNTFRalpha expression precedes that of neuron-specific beta tubulin, Hu antigen, and Q211 antigen, which are markers expressed in developing sensory neurons. [3H]Thymidine-labeling studies showed the onset of CNTFRalpha expression during terminal mitosis of sensory neuron precursors, making CNTFRalpha the earliest known neuronal marker in the DRG. CNTFRalpha-mediated signal transduction was demonstrated in E7 and E11 DRG neuron cultures by CNTF-induced STAT3 phosphorylation. Although low ligand concentrations (5 pM) elicit STAT3 phosphorylation in E7 and E11 DRG neurons, a survival response is only observed in neurons from E11 DRG. This implicates a complex readout mechanism downstream of STAT3 phosphorylation leading to different cellular responses that depend on the age of the DRG neuron. These results argue against a role of CNTFRalpha ligands in the control of early neuron survival but are compatible with other functions in neurogenesis and sensory neuron development.

Animals↗

PubMed1997

Identification of caries risk children and prevention of caries in pre-school children.

A special model for dental care in pre-school children was used in a small clinic in the county of Blekinge in southern Sweden. The model is based on screening of caries risk performed by a dental assistant before the caries attack. Any single risk factor or risk behavior in pre-school children was considered. The aim was to 1) evaluate the dental assistant's selection of caries risk children up to the age of three years, 2) compare dental health variables in 4 yr olds in the test clinic with those for the whole county in 1994 and 3) compare time spent by the dentist and the dental assistant in the test clinic and in the whole county per child up to the age of four. 102 children participated. One specially trained dental assistant screened all children using background factors combined with clinical examinations at ages 1, 2 and 3. Eighty-two children participated each year from one year. A systematized form for questioning the parents was used. Individual caries prevention was given including fluoride and antimicrobial treatments as well as fissure sealants in primary molars at caries risk. The proportion of children with caries lesions at four years and a caries risk assessment up to the age of two was 1.0 (sensitivity). The proportion of children with no caries lesions at four years and no caries risk assessment at year two was 0.7 (specificity). The most frequent risk factors found at 2 yrs were frequency order: lack of oral hygiene (visible plaque), deep fissures in molars and frequent intakes of sweet drinks. The proportion of children with no caries lesions at 4 yrs of age in the test clinic was 92.9% compared to a county mean of 76.4%. In the group of children where a risk assessment was made each year from one year the proportion of caries free children was 96.3%. The total time spent per child in the test clinic was 22 minutes more than the county mean. However, dentist's time, excluding assistance, was 28 minutes less in the test clinic. The results suggest that the model used for caries prevention in pre-school children is cost-effective, and that dental health can be remarkably improved.

Anti-Infective Agents↗

PubMed1996

A higher order Bayesian neural network with spiking units.

We treat a Bayesian confidence propagation neural network, primarily in a classifier context. The one-layer version of the network implements a naive Bayesian classifier, which requires the input attributes to be independent. This limitation is overcome by a higher order network. The higher order Bayesian neural network is evaluated on a real world task of diagnosing a telephone exchange computer. By introducing stochastic spiking units, and soft interval coding, it is also possible to handle uncertain as well as continuous valued inputs.

Action Potentials↗

PubMed1996

A 3-year clinical evaluation of Ketac-Silver restorations in primary molars.

Occlusal and proximal caries lesions in primary molars in 4-7-yr-old children with a high caries activity were restored with a cermet, Ketac Silver. Slice prepared proximal surfaces were restored with one surface restorations. A total number of 119 restorations were available for evaluation. Fiftysix percent of the restorations included two or more tooth-surfaces. The restorations were evaluated 1 yr, 2 yrs and 3 yrs after placement using the USPHS criteria. The percentage of successful and acceptable restorations was 66% after 1 yr, 56% after 2 yrs and 46% after 3 yrs. Three year after placement 27% of the restorations showed severe abrasion into the dentin or were lost, 10% showed poor margin adaption or were fractured. Slightly more than 8% showed deep margin discoloration and the same amount showed secondary caries lesions. There was a general trend toward poor results as both the size of the restoration and the number of surfaces per tooth restored increased. The results indicate that Ketac-Silver is not useful for restorations in primary molars especially not for large restorations in caries active children.

Cermet Cements↗

PubMed1995

Juvenile myoclonic epilepsy and human leukocyte antigens.

The idiopathic generalized epilepsies (IGE) occur with a high aggregation within families. Juvenile myoclonic epilepsy (JME) is recognized as a commonly occurring form of idiopathic generalized epilepsy. A possible association between JME and HLA antigens was investigated by serological typing of human leukocyte antigens (HLA) class I antigens and by DNA oligotyping of class II antigens. Twenty-four patients and 129 controls, all Caucasians of Scandinavian descent, were tested. Uncorrected there was a significant positive association (Relative risk (RR) = 8.07) to B17 and a significant negative association (RR = 0.13) to B8 as well as DRB1*3. The negative association to DQ alleles DQA1*0501 and DQB1*0201, which are in strong linkage disequilibrium with the alleles B8 and DRB1*3, was weaker and not significant, thus giving no clue as to a primary HLA-DQ association of JME.

Adolescent↗

PubMed1995

[Normal values for relative Doppler indices. A/B ratio, resistance index and pulsatility index of the uterine artery and umbilical artery in normal pregnancy. A longitudinal study].

37 women (of a total of 50) with an uneventful obstetric history, normal course of a singleton pregnancy and spontaneous delivery at term (> 37 weeks, birthweight > 10th centile) were studied at two to four weeks intervals in a longitudinal design using cw-Doppler velocimetry (Doptek 9013,4MHz, SPTA 30 mWcm2, high pass filter 200 Hz, Chichester, U.K.) to establish normal reference values for Doppler flow velocity waveform indices (DI) A/B ratio, RI, PI obtained from uterine and umbilical arteries from 16 to 40 weeks of gestation. Readings from the placental (p) and non-placental (np) uterine and umbilical arteries formed the database from which percentiles (5th, 50th, 95th) were calculated for weeks 16, 20, 24, 28, 32, 36 and 40 of gestation. DI consistently decreased from week 16 to term. For the uterine arteries this decrease was significant from weeks 16 to 24 with a further but insignificant decrease from 24 weeks to term. Up to 24 weeks DI values obtained from the placental side were significantly lower than those from the non-placental side. DI values from the umbilical arteries decreased continuously from 16 weeks to term with a significantly negative correlation DI values to gestational age.

Adult↗

PubMed1994

Dental assistants' ability to select caries risk-children and to prevent caries.

A new model for dental care in children has been used since 1987 in a small-town clinic in the county of Blekinge in southern Sweden. The model is based on early screening of caries risk, performed by dental assistants. The purpose is to obtain an individual assessment of the need of preventive dental care among pre-school children, in order to prevent dental caries and gingivitis. The aim was to 1) evaluate the dental assistants' selection of caries risk children up to the age of three by comparing dental health variables in 4 yr olds in the test clinic with those for the whole county and 2) compare the time spent by the dentists and the dental assistants in the test clinic and in the whole county per child up to the age of four. 102 children participated. Specially trained dental assistants screened children likely to develop caries lesions using background factors combined with clinical examinations at ages 1, 2 and 3. A systematized form for questioning the parents was used. Individual caries prevention was given. Dental health and time spent were analyzed. The proportion of children with caries lesions at four years and a caries risk assessment up to the age of three was 11/19 = 0.58 (sensitivity). The proportion of children with no caries lesions at four years and no caries risk assessment up to the age of three was 82/83 = 0.99 (specificity). The proportion of children with no caries lesions at 4 yr of age in the test clinic was 81.4% compared to a county mean of 77.2%.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗

PubMed1993

Prediction of behavior-management problems in 3-year-old children.

The aim was to determine power of nondental background factors to predict behavior-management problems at the first dental visits of 3-yr-old children. A total of 273 children from three kinds of residential area--city, town, and rural area--in Sweden took part. The parents were interviewed before the child's dental visit. The behavior of the child was rated by registering the degree of acceptance according to the method of HOLST & CROSSNER. The following steps were rated: entering the dental treatment room, mirror in mouth, probe on fingernail and tooth, air-blower on hand and in mouth, sitting in the dental chair, and examination. The behavior was then analyzed in relation to the answers of the interviews, and a logistic regression model was used to calculate the power of the variables, separately or combined, to predict behavior-management problems. Seventy-six percent of the children cooperated well at the dental examination; 13% reacted reluctantly, and 11% reacted negatively. Two interview variables had statistically significant predictive power: the parent's expectation of a negative reaction from the child in the dental situation and the child's anxiety when meeting unfamiliar people. Sixty-nine percent of child patients accepted the examination while sitting alone in the chair. Sitting alone used as a predictor for cooperation showed sensitivity 0.80, specificity 0.71, predictive value for positive test 0.44, and predictive value for negative test 0.94.

Child Behavior↗

PubMed1993

A flexible and fault tolerant query-reply system based on a Bayesian neural network.

A query-reply system based on a Bayesian neural network is described. Strategies for generating questions which make the system both efficient and highly fault tolerant are presented. This involves having one phase of question generation intended to quickly reach a hypothesis followed by a phase where verification of the hypothesis is attempted. In addition, both phases have strategies for detecting and removing inconsistencies in the replies from the user. Also described is an explanatory mechanism which gives information related to why a certain hypotheses is reached or question asked. Specific examples of the systems behavior as well as the results of a statistical evaluation are presented.

Animals↗

PubMed1993

Formation of free radicals during phacoemulsification.

During phacoemulsification cavitation bubbles are formed. These bubbles are believed to be one source of damage to corneal endothelium seen after phacoemulsification. Free radicals are induced whenever cavitation bubbles implode. The aim of this study was to confirm the initiation of free radicals by phacoemulsification and to correlate the power of ultrasound in the phacoemulsification process to the amount of free radicals formed, using both in vitro and in vivo techniques. The formation of free radicals was determined by adding luminol to a buffer and measuring the chemoluminescence in vitro and in rabbit eyes (Lumacounter 2080 or a single-photon-counting apparatus) during phacoemulsification. The data obtained show that free radicals are formed during phacoemulsification and that the amount of free radicals correlates with the power of ultrasound. Furthermore, the radical formation could be inhibited by the radical scavengers SOD, Healon and Healon GV. These results were achieved both in vitro in the test tube and in vivo in rabbit eyes. By showing that the addition of SOD to the irrigation buffer during phacoemulsification decreases the corneal endothelial cell damage, we show that free radicals could have a role in postoperative complications seen clinically.

Animals↗

PubMed1992

Inflammatory response in the rabbit eye after intraocular implantation with poly(methyl methacrylate) and heparin surface modified intraocular lenses.

Early inflammatory responses in rabbit eyes after anterior chamber implantation with poly(methyl methacrylate) (PMMA) and heparin surface modified intraocular lenses (IOLs) and after cataract extraction and implantation with PMMA and heparin surface modified intraocular lenses (IOLs) were investigated between 1 and 30 days postoperatively. The number of white blood cells in the aqueous humor, the distribution of white blood cell subsets, and the interleukin-1 (IL-1b) levels were studied. At one day postoperatively, there was a significantly smaller number of white blood cells in eyes with heparin surface modified IOLs than in eyes with PMMA IOLs after both anterior chamber implantation and cataract surgery and capsular bag implantation. At one day postoperatively, 87% of the cell population in eyes with PMMA IOLs were neutrophilic granulocytes. Two days later the neutrophilic granulocytes had decreased to 13% and at seven days they were gone. At 14 days the frequency was 7% and at 30 days it was 27%. The fraction of monocytes/macrophages in the cell population was 9% (day 1), 79% (day 3), 94% (day 7), 81% (day 14), and 72% (day 30). The fraction of lymphocytes was low throughout the test period (1% to 10%). The percentages were almost the same in eyes with heparin surface modified IOLs and there was no significant difference in the distribution of white blood cell subsets between the two lens materials. The IL-1 was not detected in any of the samples (day 3, day 7, and day 30). Inactivated macrophages and/or levels under detection limits could be the reason.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Cellular reaction following cataract surgery with implantation of the heparin-surface-modified intraocular lens in rabbits with experimental uveitis.

The inflammatory response after cataract surgery and intraocular lens (IOL) implantation was studied in rabbits with endotoxin-induced uveitis. On days 1, 3, 7, 14, and 30 postoperatively the rabbits were sacrificed and the number of white blood cells in the aqueous humor and cellular deposits on the IOLs were estimated. On days 14 and 30 the rabbits also had slitlamp examination to study the clinical outcome of the surgery. At day 1 after lens extraction and IOL implantation, the number of white blood cells in the aqueous humor was significantly lower (P < .05) in eyes with heparin-surface-modified (HSM) IOLs (795.2 +/- 262.9; mean +/- SEM) than in eyes with poly(methyl methacrylate) (PMMA) lenses (1386.5 +/- 247.9). No differences were seen at day 3, 7, 14, or 30 postoperatively. The choice of IOL material had no effect on the amount of cell deposits on the IOL surface or on clinical parameters such as anterior synechias, posterior synechias, fibrosis, and posterior capsular opacification. There was a trend toward a greater number of cellular deposits on the PMMA lenses, but this was not statistically significant. This study provides further evidence of improved biocompatibility of the HSM PMMA lens, as demonstrated by a decreased acute inflammatory response.

Acute Disease↗

PubMed1992

Long-term stability of heparin-surface-modified intraocular lenses in vivo.

In vivo long-term stability of intraocular lens surfaces, modified by immobilized heparin, was studied. Lenses were implanted in the anterior chamber of rabbits and analyzed for surface concentration of heparin after varying periods of time up to two years. A new method using adsorption of 125iodine-labeled protamine was developed for quantitative measurements of immobilized heparin. Another assay, based on a monoclonal antibody against heparin, was also included. The study showed that surface-immobilized heparin did not degrade or desorb to any measurable degree during a two-year follow-up.

Animals↗