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Biomedical subjects

W Dietz

Publications and source records attributed to W Dietz.

At least 19 recordsLinked to original sources
PubMed2005

Scanning electron micrograph analysis of hypomineralized enamel in permanent first molars.

UNLABELLED: First molars with cream- to yellow-coloured demarcated opacities of the enamel, often in combination with severe loss of substance, are common in many child populations. The aetiology is obscure. AIM AND METHOD: The aim of this study was to study the ultrastructure of the enamel of 10 affected teeth by means of scanning electron microscopy (SEM) in order to gain a better understanding of the clinical appearance and treatment problems of this condition, and to find some clues to its aetiology. RESULTS: The basic enamel structure with enamel rods and interrod zones was found in porous parts of the enamel, as well as in normal parts, but the packing of the hydroxylapatite crystals seemed to be looser and less well organized in the porous parts. The border between normal and hypomineralized enamel was usually distinct, and followed the direction of the rods. The preserved basic structure indicates normal function of the ameloblasts during their secretion phase, but impaired function during their maturation stage. CONCLUSION: Considering the poor etch profile, it seems reasonable to recommend removal of all affected enamel surrounding the cavity, if possible, and to use a glass ionomer filling with its chemical bonding to tooth substrate, when restoring first molars with remaining affected enamel.

Dental Enamel↗
PubMed2004

Antibiotic prophylaxis influences cardiovascular stability in complicated surgery.

OBJECTIVE: Antibiotic prophylaxis is used in many surgical procedures but there are frequent cardiovascular instabilities following antibiotics in perioperative period. A clinic modelling randomised trial (CMRT) in pigs was developed to compare the effects of 2 commonly used antibiotic combinations on cardiovascular stability during major surgery. MATERIALS AND METHODS: Thirty pigs (both sexes) were randomised into 3 groups, receiving either saline (placebo), co-amoxiclav or cefuroxime/metronidazole in clinically relevant doses as antibiotic prophylaxis. A laparotomy was performed and the abdomen remained open. Surgical complications were simulated by removing one third of the blood volume. For fluid resuscitation, 500 ml hetastarch (HAES(TM)) were infused rapidly (therapy of complication) and polymyxin B (15 mg/kg bodyweight) was applied for induction of histamine release reactions (complication of therapy). The main end points were histamine release reactions, these were classified by 2 blinded investigators. RESULTS: Neither cardiovascular changes nor histamine release reactions were detected immediately after the administration of antibiotics or placebo alone. Plasma histamine concentrations increased after bleeding in the co-amoxiclav group (p < 0.05). After fluid resuscitation and induction of anaphylactoid reactions, the median histamine release and cardiovascular changes were not significantly different between the groups. However, the incidence of typical histamine release related reactions differed significantly between the groups: 8/10 for the controls, 6/10 in the co-amoxiclav and 2/10 in the cefuroxime/metronidazole group (p < 0.05). CONCLUSIONS: The stability and reproducibility of this model clearly demonstrated the concept of a 'clinic modelling randomised trial' as a useful tool. Antibiotic prophylaxis influences the organism's capability to cope with intraoperative bleeding and fluid resuscitation problems. Indeed antibiotic prophylaxis may be beneficial. These effects of antibiotics could only be demonstrated in complex surgical models. Thus new antibiotics should be investigated in complex animal models prior to prospective randomised clinical trials or usage in clinical practice.

Animals↗
PubMed2004

A modified Ce/Mg-BCIP-NBT formazan/indigoblue technique for demonstration of non-specific alkaline phosphatase activity.

The wide ranged structurally variability of formazans and their accessibility for auxiliary additives as redoxmediators or metals provide an easy tunable chromogenic visualization technique. We present here an improved nitro blue tetrazolium (NBT) 5-bromo-4-chloro-3-indolyl phosphate (BCIP) method which is superior to the classical McGadey's procedure regarding proper precipitation and localization as well as sensitivity. Different metal additives as well as the overall reaction course modifying additives (redox mediators, chelating additives, buffer) were optimized.

Alkaline Phosphatase↗
PubMed2001

Secondary ion mass spectrometry and X-ray microanalysis of hypomineralized enamel in human permanent first molars.

A common finding in Swedish children is hypomineralization in first molars of unknown cause. Little is known about the chemical composition of the disturbed enamel. The aim here was to analyse the concentration gradients for F, Cl, Na, Mg, K and Sr in hypomineralized enamel from 17 permanent molars by means of secondary ion mass spectrometry, to complete this analysis with an examination of the main matrix elements O, P and Ca by means of X-ray microanalysis, and to compare them with normal enamel. Hypomineralized enamel had a higher content of carbon and the calcium as well as the phosphorus concentration was lower than in normal enamel. The mean Ca/P ratio in hypomineralized areas was significantly lower (1.4) than in the adjacent normal enamel (1.8). The F content was highly variable in impaired enamel and higher than in normal, but close to the surface there was most often no difference between the two. Contents of Mg and K were slightly higher in hypomineralized areas, especially towards the surface. Also Na had a somewhat higher content toward the surface in defective enamel. Cl and Sr contents had negligible or no diversity in relation to the degree of mineralization.

Calcium↗
PubMed2001

Laryngeal compartmentalization after radiation therapy in a canine model.

OBJECTIVE: We set out to study the effects of radiation therapy on laryngeal tissue barriers in a canine model as described by Welsh. STUDY DESIGN: India ink was injected into 1 vocal fold on irradiated and nonirradiated canine larynges. RESULTS: The india ink dye spread more prominently into the supraglottis of the irradiated specimens by submucosal lymphatics. Larger dye volumes simulating larger tumor bulk spread to the contralateral larynx in irradiated specimens. CONCLUSION: Conservation laryngeal surgery for laryngeal carcinoma is a popular method of treatment. Some surgeons advocate partial laryngectomy for radiation failures; in other instances, it is the primary modality of treatment. These findings suggest a cautious approach when planning conservative laryngeal surgery after radiation therapy failures of glottic carcinoma.

Animals↗
PubMed2001

Focus group data pertinent to the prevention of obesity in African Americans.

The increased prevalence of obesity among African-American women makes it likely that they bear a disproportionate burden of comorbidities attributable to obesity, such as diabetes, hypertension, and hyperlipemia. These observations suggest that intensive efforts to prevent obesity should be directed at this group. This presentation provides a summary of the findings of focus groups that convened prior to the Sisters Together, Move More, Eat Better campaign in Boston. This pilot campaign was designed to increase awareness of the importance of healthy eating and physical activity among young adult African-American women. In addition, data collected by the Division of Nutrition and Physical Activity of the US Centers for Disease Control and Prevention (CDC) provide additional information about attitudes toward diet and physical activity among African American youth. Such data are essential to understand the attitudinal changes necessary to prevent obesity in these vulnerable populations.

Attitude to Health↗
PubMed2001

Focus group data pertinent to the prevention of obesity in African Americans.

The increased prevalence of obesity among African-American women makes it likely that they bear a disproportionate burden of comorbidities attributable to obesity, such as diabetes, hypertension, and hyperlipemia. These observations suggest that intensive efforts to prevent obesity should be directed at this group. This presentation provides a summary of the findings of focus groups that convened prior to the Sisters Together, Move More, Eat Better campaign in Boston. This pilot campaign was designed to increase awareness of the importance of healthy eating and physical activity among young adult African-American women. In addition, data collected by the Division of Nutrition and Physical Activity of the US Centers for Disease Control and Prevention (CDC) provide additional information about attitudes toward diet and physical activity among African American youth. Such data are essential to understand the attitudinal changes necessary to prevent obesity in these vulnerable populations.

Attitude to Health↗
PubMed2000

Nutrient intakes and dietary patterns of young children by dietary fat intakes.

OBJECTIVE: To determine whether low fat intake is associated with increased risk of nutritional inadequacy in children 2 to 8 years old and to identify eating patterns associated with differences in fat intake. STUDY DESIGN: Using 2 days of recall from the Continuing Survey of Food Intake by Individuals (CSFII), 1994 to 1996, we classified 2802 children into quartiles of energy intake from fat (<29%, 29% to 31.9% [defined as moderate fat], 32% to 34.9%, and > or =35%) and compared nutrient intakes, the proportion of children at risk for inadequate intakes, Food Pyramid servings, and fat content per serving across quartiles. RESULTS: More children in quartile 2 were at risk for inadequate intakes of vitamin E, calcium, and zinc than children in higher quartiles (P <.0001); more children in quartiles 3 and 4 were at risk for inadequate intakes of vitamins A and C and folate (P <.001). Fruit intake decreased across quartiles (P <.0001); whereas vegetable, meat, and fat-based condiment intakes increased (P <.0001). Fat per serving of grain, vegetables, dairy, and meat increased across quartiles (P <.0001). CONCLUSIONS: Moderate-fat diets were not consistently associated with an increased proportion of children at risk for nutritional inadequacy, and higher-fat diets were not consistently protective against inadequacy. Dietary fat could be reduced by judicious selection of lower-fat foods without compromising nutritional adequacy.

Child↗
PubMed1999

Using 3 data sources and methods to shape a nutrition campaign.

The first objective of this research was to define a target population of African-American women more clearly. The second was to provide specific information about the needs and preferences of that population in order to design an effective, culturally relevant, community-based communications campaign to promote more healthful lifestyles. Data collection and analysis included the following: interviews with 10 community nutritionists and the director of the State Office of Nutrition, 6 focus groups with a total of 47 members of the target population, and direct observation and documentation of key community resources. This approach, called "triangulation," permits more in-depth understanding of issues, provides different perspectives on the problem, and helps ensure accuracy of conclusions. Interviews with nutritionists identified young African-American women as the appropriate target population for the campaign. These interviews and the focus-group discussions confirmed the acceptability of higher weight and better body-esteem among African-American women than among white women. Both the nutritionists and the focus-group members identified the need and desire for information and skills related to food preparation and provided specific direction for program content. Community observation confirmed the need for food markets with merchandise of consistently high quality, especially in the fresh and frozen produce sections. Observation also helped identify community services and programs. The 3 sets of data, which augmented a comprehensive literature review, provided a firm foundation for the campaign's design and development. Dietitians and nutritionists working in community settings can use triangulation to gain a better understanding of their populations in order to develop more effective interventions.

Adolescent↗
PubMed1999

How to tackle the problem early? The role of education in the prevention of obesity.

The major issues that confront the clinician in relation to childhood obesity are identifying children at risk, deciding the goal and focus of therapy, and determining how to maintain weight loss. The severity of obesity and the age at which it is present appear to be significant determinants of whether childhood obesity will persist into adulthood. At any age, severe obesity is more likely to persist, and obesity present in adolescents is much more likely to persist than obesity in young children. If a child has obese parents, the risk that their obesity will persist to adulthood increases, though the magnitude of that risk varies with the age of the child. The goals of therapy depend on the child's age and the severity of obesity-related complications. Assessment of the family's readiness to change represents the first focus of therapy. A reduction in time spent watching television, coupled with family involvement and a diet that aims to reduce or eliminate high caloric density foods is the best approach in most cases. Children or adolescents who have an emergent complication of obesity are candidates for aggressive weight reduction such as the protein modified fast. More aggressive therapies, such as drug therapy or gastric bypass surgery, must be considered as experimental in children and adolescents.

Child↗
PubMed1999

Morphology of dental enamel and dentine-enamel junction in osteogenesis imperfecta.

OBJECTIVES: The aim of this study was to examine the morphology of primary and permanent human enamel, and the dentine-enamel junction, in individuals with osteogenesis imperfecta (OI) type I, III and IV in undecalcified sections using polarized light microscopy, microradiography and scanning electron microscopy (SEM), and to relate the findings to the type of OI. SAMPLE AND METHODS: Extracted or exfoliated teeth from 15 patients representing the OI types I, III and IV (12 primary teeth from seven patients, and 11 permanent teeth from eight patients). Ten primary and nine permanent teeth from normal healthy patients served as controls. The teeth were serially cut longitudinally in a bucco-lingual direction and contact microradiographs were made. The sections were examined in polarized light. Sections of primary and permanent teeth were examined by means of SEM. RESULTS: This study shows that the permanent enamel from patients with OI exhibits few structural changes. No relationships were found between enamel morphology and the types of OI (I, III, IV). Primary enamel appeared to be slightly more irregularly mineralized, especially in cases with the additional diagnosis dentinogenesis imperfecta. The major findings were deviations in association with the dentine-enamel junction, and locally a lower degree of mineralization. CONCLUSIONS: The mesodermal disease OI might also be manifested in ectodermal enamel, probably because of suboptimal mesenchymal-ectodermal interactions during amelogenesis.

Dental Enamel↗
PubMed1999

Discrimination of morphological findings in dentine from osteogenesis imperfecta patients using combinations of polarized light microscopy, microradiography and scanning electron microscopy.

OBJECTIVES: The aim of this study was to investigate the morphological appearance of dentine in teeth from individuals with osteogenesis imperfecta type I, III and IV using different histological techniques, and to correlate morphological findings to different types of osteogenesis imperfecta. SAMPLE AND METHODS: Extracted or exfoliated primary and permanent teeth were collected from 15 patients with the osteogenesis imperfecta diagnoses I, III or IV, with or without the additional diagnosis dentinogenesis imperfecta. Ground and decalcified sections were prepared from the teeth. Histo-morphological studies of the dentine were performed utilizing light and polarized light microscopy, microradiography and scanning electron microscopy. RESULTS: Characteristic findings were irregular tubules, remnants of capillary inclusions and obliterated pulps. All types of osteogenesis imperfecta exhibited similar types of dentine aberrations, but patients with type III or IV had a higher frequency of aberrations when compared to type I. CONCLUSIONS: The combination of either polarized light microscopy or micro-radiography, together with scanning electron microscopy, gave the most amount of morphological information from dentine samples. In addition, aberrations in dentine structure were more clearly observable. Light microscopy was not critical for the analyses.

Adolescent↗
PubMed1999

[Clinical guidelines as part of total quality management. Analysis of heterogenous treatment concepts of sepsis in various clinics with computer assisted generation, logical testing and complexity assessment of clinical algorithms].

Generation, local tailoring, implementation and evaluation of clinical guidelines is an integral part of quality management. Clinical guidelines are intimately related to the independency of physicians' decisions. By this the physicians should be responsible for guideline development and guarantee the use of adequate methods of total quality management and outcome assessment. Formal consensus finding and transparency of evidence are necessary to guarantee the use of guidelines. Clinical algorithms are highly formalized and they are well suited for generation and analysis by the software ALGO. Determination of complexity and comparison of the clinical contents of algorithms is done by the scores CASA (Clinical Algorithm Structural Analysis) and CAPA (Clinical Algorithm Patient Abstraction). In a study of 22 clinical departments on treatment management concepts in sepsis following anastomotic insufFiciency in colorectal carcinoma a considerable heterogeneity was shown using this program.

Algorithms↗
PubMed1998

Aspects of teeth from archaelogic sites in Sweden and Denmark.

The purpose of this study was to examine ground sections of primary second molars and permanent first molars from the same jaws. Teeth from 11 individuals were collected from archaeologic sites in Sweden and Denmark. Longitudinal buccolingual sections were examined in a polarization light microscope and in a Philips scanning electron microscope (SEM). The seven teeth from Sweden appeared to have been subjected to environmental influences at their burial site, which had affected both the dentin and the enamel. The teeth from the Danish sites had a normal color, and no disintegration of the dentin was seen. The general morphologic appearance was normal in all primary and permanent teeth. The position of the neonatal line indicated a normal full-term gestational age. The observed accentuated incremental lines in both the primary and permanent enamel suggested periods of dietary changes, possibly related to periods of illness. SEM images of the surface area of the Swedish teeth showed an extremely porous enamel surface with severe changes in the prism structure as an effect of acid penetration. The Danish teeth did not show any marked changes in the enamel.

Acids↗
PubMed1998

[Effect of perioperative antibiotic prophylaxis on hemodynamic stability during surgery: detection of complex interaction in a simulated clinical randomized animal study].

In a clinic modelling randomised trial (CMRT) in three groups of 10 land-race pietren pigs each it could be shown that the influence of prophylactic antibiotic administration on intraoperative hemodynamic stability and histamine release is only evident, if by stepwise addition of complicating factors the overall complexity of the experimental setting is increased. Different antibiotic regimen for prophylaxis significantly affected the incidence of cardiovascular instabilities only after relevant blood loss, restoration of circulation and subsequent submaximal induction of anaphylactoid reactions by the histamine liberator Polymyxin B. In conclusion, preclinical testing of therapeutic agents in complex clinic modelling randomised trials should be mandatory to avoid the possible hazards of misconducted clinical trials.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed1998

[Reduction of cardiovascular disorders by preventive perioperative antihistamine administration in general surgery: are the drugs interchangeable?].

In clinical reality the drugs used for H1/H2-prophylaxis are not restricted to the combination of dimetinden/cimetidine, also only for this combination the effectiveness for preventing severe cardiorespiratory disturbances is proven in a randomised controlled clinical trial. However, it is almost impossible to conduct such an extended clinical trial in order to check all possible combinations. Instead of this, we developed a complex animal model featuring clinical variability and the principles of a well conducted randomised controlled clinical trial (CMRT = clinic modelling randomised trials), to evaluate different H1/H2 combinations. In this CMRT in pigs (four groups of 15 animals), the H1/H2 combination of dimetinden/cimetidine and dimetinden/famotidine showed an effectiveness similar to the randomised clinical trial. With dimetinden/ranitidine no significant prophylactic effect was observed. Two conclusions can be drawn: (1) CMRTs in animals are able to answer relevant clinical and research questions that otherwise only could be solved by clinical studies and may be a successful intermediate between basic research and clinical trials. (2) Drugs, even of the same substance class, may not be simply exchangeable. Hence, before changing a proven medication, trials in an adequate complex animal model (CMRT) should be mandatory.

Animals↗
PubMed1997

Pulp calcifications in traumatized primary incisors. A morphological and inductive analysis study.

The purpose of this study was to investigate histopathological changes in primary teeth following trauma, and to look for possible correlations between the morphology of pulpal calcification and clinical findings. The material consisted of 123 primary teeth from 98 Danish children aged 9-108 months (mean age 33.5 +/- 19.7 months) at the time of injury. The specimens were analyzed by means of light and scanning and transmission electron microscopy. Data from the clinical investigation and from predetermined ranked parameters from the histological analysis were processed in a computerized inductive analysis program. The results, describing patterns of co-variation, are presented as a decision tree. The most common diagnosis was intrusion luxation (54%). In 41% of all teeth, the degree of obliteration was less than 1/4 of the pulpal lumen. In most cases (79%), no denticles were visible. When present, 80% of the denticles had a bone-like appearance. Tissues occluding the pulpal lumen were either dentin-like (49%), bone-like (19%), or fibrotic (9%). It could be concluded that these varying responses could not be correlated with explicit clinical diagnoses. However, in certain combinations, histological parameters could be correlated to clinical findings.

Bone and Bones↗