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Biomedical subjects

M H Walter

Publications and source records attributed to M H Walter.

At least 19 recordsLinked to original sources
PubMed2006

Intrapyloric injection of botulinum toxin a for the treatment of persistent gastroparesis following successful pancreas transplantation.

Intrapyloric injection of botulinum toxin A (BoTx) successfully improved symptoms in idiopathic and diabetic gastroparesis (DGP) refractory to medical treatment. Therefore, we used it in three pancreas transplant patients done in our institution during the last 18 months. They had severe, persistent DGP despite successful pancreas transplantation. They received 100 units of BoTx during the first injection. The clinical effect became evident within 2 weeks after the treatment, and lasted for an average of 29 weeks (range 14-44 weeks). The patients' subjective evaluation showed improvement of their symptoms and quality of life following BoTx. Patients 2 and 3 had recurrent symptoms at 44 and 24 weeks, respectively, after the first injection; they required a second dose of 90 and 80 units, respectively. They are doing well at 3 months follow-up. Intrapyloric injection of BoTx is safe and efficient. It should be considered for treating residual DGP following successful pancreas transplantation.

Adult↗
PubMed2001

Plaque, gingival health and post-operative sensitivity in titanium inlays and onlays: a randomized controlled clinical trial.

OBJECTIVES: Few clinical data on the use of titanium for restorative appliances are available. The aim of this study was to clinically evaluate titanium restorations compared to gold alloy restorations with regard to plaque, gingival health and post-operative sensitivity. METHODS: In 54 patients, 99 titanium restorations were placed. The control group comprised 56 patients with 96 high gold alloy restorations. The material was chosen by random. Each patient received one or two Class II restorations. Plaque Index (Silness and Löe, 0-3), Gingival Index (Löe and Silness, 0-3), and post-operative sensitivity (1-4, 1=none) were rated at 2 weeks, 3 months, 6 months, 12 months, and 18 months, post-operatively. RESULTS: The mean plaque scores ranged from 0.89 to 0.99 in the titanium group, and from 0.88 to 1.04 in the gold group. The mean gingival scores ranged from 0.91 to 1.07 in the titanium group, and from 0.82 to 0.99 in the gold group. The mean plaque and gingival scores of the titanium and gold group did not differ significantly at any visit (P>0.05). To evaluate post-operative sensitivity, patients with one MOD restoration each were included, resulting in 46 titanium and 44 high gold restored teeth. Mean values of the post-operative sensitivity scores in the titanium group were significantly higher than in the gold group (P<0.05). The restoration material was found to be the dominating variable with regard to post-operative sensitivity, which was not influenced by age, sex and the application of calcium hydroxide liner. CONCLUSIONS: It is concluded that neither higher plaque scores nor adverse effects on gingival health are to be expected in titanium restorations.

Adolescent↗
PubMed2001

Multivariate analysis of oral hygiene data from a representative sample.

BACKGROUND: This analysis was based on an oral health survey with dental examination and interview by questionnaire. METHOD: The data set comprised a representative random sample of the over 14-year-old residents of the German Federal State of Saxony (n=714), in which a multivariate logistic regression analysis was conducted. The dependent variable was the debris index (DI) score of the oral hygiene index scoring system. The subjects were split into 2 groups by dividing DI scores into tertiles: those with acceptable oral hygiene (1st tertile, DI 0.00< or =1.20) and unacceptable oral hygiene (2nd and 3rd tertile, DI>1.20). The most important explanatory variable was the community periodontal index of treatment need (CPITN). RESULTS: The higher the CPITN score, the lower the probability of acceptable oral hygiene. In relation to the reference category score 0, higher CPITN scores were associated with acceptable oral hygiene, with an odds ratio 0.05 (95% confidence interval (CI)=0.01-0.23) for CPITN score 1, and an odds ratio 0.02 (95% CI: 0.01-0.08) for score 4. Further significant variables were: self-evaluation of tooth condition, gender, and the number of missing teeth.

Adolescent↗
PubMed2001

Prosthetic treatment need in a representative German sample.

Regarding declining resources epidemiological data on needs for oral rehabilitation are required. Within the framework of an oral health survey a non-stratified two-stage random sample was taken to represent the over 14-year-old population of Saxony/Germany. The participation rate was 55%. Normative need was determined by dental assessment and guidelines developed in a consensus process, subjective prosthetic treatment need by self-complete questionnaire. About 97% of the realized sample could be planned within the guidelines. About 81% had normative prosthetic treatment need. Compared with the rate of normative need the rate of subjective need (13%) was considerably lower (chi(2) P < 0;01). Different predictive parameters of subjective need were identified by logistic regression. Besides other factors subjective need was associated with giving dentist's recommendation as significant reason for prosthetic restorations [odds ratio (OR)=5;43], not believing that the own teeth were all right (OR=0;17), and the existence of prosthetic restorations (OR=3;87 for fixed restorations; OR=4;05 for removable dentures). The guidelines proved their suitability to assess normative prosthetic treatment need in oral health surveys. Further research is necessary to find adequate options for including patients' preferences in an adequate need definition.

Adult↗
PubMed2001

[Patients' need for information before surgery].

Frequently, prior to surgery, patients are provided with information in order to meet legal and hospital requirements, but without taking their psychological needs into consideration. In order to learn how to improve this situation, the present study was performed. By means of a semi-structured interview including a newly constructed card system, that avoids giving patients undemanded and possibly harmful implicit information, the need for information of 60 patients before hip- or knee-replacement surgery were investigated in great detail. The results show that 83.3% of the patients want to be prepared by the surgeon, preferably by means of an oral communication (75.0%). Most frequently the day when decision for surgery is made and the day of hospitalization were preferred as point of time for preparation (30% each). Patients were more interested in information about the operation and recovery (43.3% each) than about risks (33.3%). Only 11.7% wanted to get psychological preparation prior to surgery. We conclude that coming into contact and establishing a trustful relationship with the surgeon who does the operation is the most crucial need of surgical patients. He should give presurgical information according to the patient's needs, which often do not focus on the risks, as legal regulations do. By providing psychological preparation for the small number of patients in need, psychological specialists may contribute to improve satisfaction and outcome of surgical patients.

Adult↗
PubMed2001

Burs with guide pins for standardized tooth preparation.

OBJECTIVE: The aim of this study was to develop and test self-limiting diamond burs to ease precise chamfer preparation and to fulfill the special requirements of computer-aided design/computer-aided manufacturing and all-ceramic restorations. METHOD AND MATERIALS: Rounded cylinder (based on ISO 881) and torpedo (based on ISO 879) diamond burs with a polished guide pin, 0.5 mm in length and 0.15 mm in radius, at the front end were developed in cooperation with an industrial partner. The in vitro testing involved a total of 140 human teeth. Experimental variables were the quality of the finish line, the microhardness of the enamel, and the thermal alteration of the dentin. Conventional diamonds served as a control. RESULTS: No mechanical or thermal damage related to the bur design was found in the hard tissues that had potentially been in contact with or in close proximity to the guide pin. Microhardness of the enamel at the finish line was significantly higher when prepared with burs with a guide pin compared to conventional burs. The results of using the guide pin might indicate the beneficial effect of reduced vibration. CONCLUSION: The guide pins of the self-limiting diamond burs reduce, rather than increase, the risk of hard tissue damage at the preparation margin. No adverse effects were found. Clinical use is justified.

Body Temperature↗
PubMed2000

Arbuscular mycorrhizal fungi induce the non-mevalonate methylerythritol phosphate pathway of isoprenoid biosynthesis correlated with accumulation of the 'yellow pigment' and other apocarotenoids.

Plants and certain bacteria use a non-mevalonate alternative route for the biosynthesis of many isoprenoids, including carotenoids. This route has been discovered only recently and has been designated the deoxyxylulose phosphate pathway or methylerythritol phosphate (MEP) pathway. We report here that colonisation of roots from wheat, maize, rice and barley by the arbuscular mycorrhizal fungal symbiont Glomus intraradices involves strong induction of transcript levels of two of the pivotal enzymes of the MEP pathway, 1-deoxy-D-xylulose 5-phosphate synthase (DXS) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR). This induction is temporarily and spatially correlated with specific and concomitant accumulation of two classes of apocarotenoids, namely glycosylated C13 cyclohexenone derivatives and mycorradicin (C14) conjugates, the latter being a major component of the long-known 'yellow pigment'. A total of six cyclohexenone derivatives were characterised from mycorrhizal wheat and maize roots. Furthermore, the acyclic structure of mycorradicin described previously only from maize has been identified from mycorrhizal wheat roots after alkaline treatment of an 'apocarotenoid complex' of yellow root constituents. We propose a hypothetical scheme for biogenesis of both types of apocarotenoids from a common oxocarotenoid (xanthophyll) precursor. This is the first report demonstrating (i) that the plastidic MEP pathway is active in plant roots and (ii) that it can be induced by a fungus.

Carotenoids↗
PubMed2000

Clinical fit of Procera AllCeram crowns.

STATEMENT OF PROBLEM: Color stability, strength, and accuracy of fit are the main requirements for complete-ceramic crowns. The Procera AllCeram crown system is a CAD/CAM system used to fabricate individual complete-ceramic crowns that have a dry sintered, aluminum oxide core and appear to match clinical requirements. However, there are few articles about the clinical fit of all-ceramic crowns. PURPOSE: This in vivo study measured the accuracy of fit of Procera AllCeram crowns in anterior and posterior teeth. MATERIAL AND METHODS: The clinical fit of 80 anterior and posterior Procera AllCeram crowns was evaluated by a replica technique with a light body silicone to fill space between crown and tooth and a heavy body silicone to stabilize the light body film. After removal from the artificial crowns, the replicas were segmented, and measurements of the film thickness were performed with a light microscope. RESULTS: Medians of mean marginal gap widths were between 80 and 95 microm in anterior teeth and between 90 and 145 microm in posterior teeth. Medians of maximal marginal gap widths ranged from 80 to 180 microm in anterior teeth and from 115 to 245 microm in posterior teeth. CONCLUSION: The accuracy of fit achieved by Procera AllCeram was comparable to other conventional and innovative systems.

Adult↗
PubMed1998

Margin quality of titanium and high-gold inlays and onlays--a clinical study.

OBJECTIVES: Unalloyed titanium may be an economical substitute for gold alloys. The purpose of this study was to evaluate the suitability of unalloyed titanium as an alternative to gold alloys for posterior inlay and onlay restorations. METHODS: Fifty-four patients received 99 titanium restorations, 56 patients 96 gold alloy restorations. All titanium restorations were cast in a vacuum-pressure casting machine. Two weeks after insertion the clinical margin integrity was evaluated by replica technique. The maximum marginal gaps were assessed under the optical measuring microscope. The two tailed t-test for independent samples was used for statistical analysis. RESULTS: Accuracy of fit was significantly better in gold alloy than in titanium restorations. Mean maximum marginal gap between restoration margin and tooth structure were 72 +/- 18 microns (mean +/- S.D.) for titanium and 64 +/- 18 microns (mean +/- S.D.) for gold restorations. SIGNIFICANCE: Though marginal gap widths in titanium restorations did not yet match the gold standard, the data justify the use of titanium as an alternative to gold alloy for inlay and onlay restorations.

Adolescent↗
PubMed1996

Bean ribonuclease-like pathogenesis-related protein genes (Ypr10) display complex patterns of developmental, dark-induced and exogenous-stimulus-dependent expression.

The intracellular pathogenesis-related (PR) proteins of common bean (Phaseolus vulgaris L.) are encoded by a highly polymorphic family of at least 20 genes. One member, the Ypr10*c gene, has been isolated and characterised. The deduced amino acid sequence of the encoded protein, PR-10, exhibits similarities to tree-pollen allergens, to food allergens from celery and apple and to ginseng ribonuclease peptide sequences. We show by RNA blot analysis that the Ypr10 gene family, including Ypr10*c, is strongly expressed in bean roots. In leaves Ypr10 transcript levels are low in young and mature stages but are elevated during senescence and in diseased states. Dark treatment of leaves causes strong induction of Ypr10 transcripts, which is reversible by light, and diurnal rhythms of transcript accumulation during the night are observed. Ypr10 genes are responsive to external stimuli related to pathogen-defence such as glutathione or salicylic acid. Transcriptional activity of a Ypr10*c promoter-beta-glucuronidase fusion gene in transgenic tobacco was observed in roots, in developing xylem and phloem of stems, and in the blade of senescent leaves, with highest levels at the onset of senescence. The most striking characteristic of developmental expression was the specific localisation of beta-glucuronidase activity in the transmitting tract of styles in flowers at anthesis. Feeding of various pathogen-related and stress-related stimuli to young tobacco leaves led to accumulation of GUS activity in leaf blades. We identify considerable spatio-temporal similarities between reported expression patterns of Ypr10 genes and ribonuclease genes, which, together with the significant sequence similarity to the ginseng ribonuclease, support the hypothesis of a ribonuclease function for PR-10 proteins and allow the prediction of possible biological roles.

Allergens↗
PubMed1994

Characterization of a bean (Phaseolus vulgaris L.) malic-enzyme gene.

We have isolated a genomic clone encoding a plant NADP(+)-dependent malic enzyme (NADP-ME). This clone, isolated from bean (Phaseolus vulgaris L.), covers the entire gene (exons, introns) and 5'-flanking regions. DNA sequencing defines 20 exons spanning approximately 4.5 kb, which range over 48-235 bp in size. All 19 introns are fairly small (79-391). The first intron resides in the 5'-untranslated leader sequence. Introns 10, 11 and 16 are located at positions identical to a rat malic-enzyme gene. In the promoter region, a TATA box (TATATATA) is easily recognized 41 bp upstream of a single transcription-initiation site. Two potential cis-acting elements with homology to elements from plant genes, activated by UV light and fungal elicitors, were identified at positions -153 and -312, respectively. Southern-blot analysis suggests a single gene copy, but also other distantly related genes, in the bean genome. The deduced NADP-ME protein of 589 amino acids exhibits features consistent with a cytoplasmic location. We describe the organization of the NADP-ME protein into functional domains located on separate exons. The evolution of malic-enzyme genes coding for isoforms in different cellular compartments of plants and animals is discussed.

Amino Acid Sequence↗
PubMed1994

Endoscopic sphincterotomy-induced pancreatitis: increased risk associated with nondilated bile ducts and sphincter of Oddi dysfunction.

OBJECTIVE: to evaluate the relationship between common bile duct diameter and the risk of sphincterotomy-induced pancreatitis. METHODS: Two hundred and ten consecutive patients were prospectively investigated. Patients were divided into three groups according to the indication for sphincterotomy: Group I had common bile duct stones (n = 108), group II had sphincter of Oddi dysfunction (n = 48), and group III had sphincterotomy for other indications (n = 54) (i.e., stent, dilation). RESULTS: There were 62 males and 148 females with a mean age of 60 yr (range 15-93 yr). Eleven of the 210 patients (5.2%) developed pancreatitis. Other sphincterotomy-induced complications were bleeding (n = 2), cholangitis (n = 2), retroperitoneal duodenal perforation (n = 1), and bile duct leakage (n = 1). The percentages of pancreatitis in groups I (3.7%), II (12.5%), and III (1.9%) were significantly different (p = 0.03). Patients with nondilated common bile ducts (< or = 10 mm) had more pancreatitis than patients with dilated common bile ducts (8.8% vs. 2.8%), but the difference was not significant (p = 0.07). However, when group III was excluded from the analysis, there was a significant difference in the percentage of pancreatitis between the patients with nondilated bile ducts and those patients with dilated bile ducts (13.1% vs. 2.2%, respectively; p < 0.01). Analysis for trend did not show a significant inverse relationship between bile duct diameter and the rate of sphincterotomy-induced pancreatitis. However, for all complications combined, the inverse relationship between bile duct diameter and rate of sphincterotomy-induced complications was significant: < or = 5 mm (23.1%), > 5-10 mm (13.8%), > 10-15 mm (3.2%), > 15 mm (2.4%) (p = 0.002). CONCLUSIONS: Endoscopic sphincterotomy is more hazardous in patients with nondilated bile ducts and sphincter of Oddi dysfunction. Further studies are needed to determine whether pancreatic stenting reduces the risk of sphincterotomy-induced pancreatitis in those clinical settings.

Common Bile Duct↗
PubMed1993

The impact of a 'guided self-help group' on bulimic women: a prospective 15 month study of attenders and non-attenders.

Bulimic women (N = 19) interested in a 'guided self-help group' were assessed by structured interviews and standardized tests. Eleven decided to attend the group, eight did not. Ten attenders (regular attendance of at least 6 months) and five non-attenders were followed for up to 6 months (mail questionnaires) and for 15 months (interviews) respectively. All the attenders and four non-attenders initially fulfilled DSM-III-R criteria for bulimia nervosa. After 15 months five attenders still met these criteria, whereas five improved to the point that they no longer did. Attenders showed significant improvement in specific psychopathology (drive for thinness, bulimia), general psychopathology (depression) and psychosocial adjustment, whereas non-attenders did not. However, three of five non-attenders also improved to a subclinical level, thus reflecting the natural course of the illness. Despite the small sample size our study indicates self-help as a valuable tool in overcoming an eating disorder.

Adult↗
PubMed1993

Studies on laser- and plasma-welded titanium.

In recent years, titanium has become a material of major interest in prosthetic dentistry. Due to its chemical properties, titanium has to be processed differently from conventional alloys. In this paper, two different methods of welding were investigated. Specimens machined from pure titanium rods were fused either by laser welding or plasma welding. Hardness profiles and light microscopy images were taken in the region of the weld. The mechanical properties were tested by alternating bending fatigue tests up to 3 million cycles. Light microscopy images and hardness profiles showed a larger heat-affected zone after plasma welding compared to laser welding. No significant differences comparing fatigue strength could be found between the two methods of welding. However, extreme loads led to earlier fatigue in the plasma-welded specimens. SEM images of the laser-welded joints showed fractures in the welding zone, while the plasma-welded specimens fractured mostly beyond the heat-affected zone. From these results, it can be assumed that both methods are suitable for welding titanium. At the moment, laser welding is the more suitable technique in dentistry because of its lower thermal alteration of the workpieces.

Dental Soldering↗
PubMed1992

Computer-aided evaluation of occlusal load in complete dentures.

A computerized diagnostic system was tested for its capability to evaluate the occlusal equilibrium of complete dentures. Its electronic sensor foil was calibrated to intraorally compute a load index for the left and right sides of the denture. The index is calculated by the measured force and number of occlusal contacts. Perfect equilibrium is given by a ratio of load left-to-load right of 1:1. Centric occlusion of complete dentures was examined before and after remounting. A good correlation between load index and the occlusal relationship on the articulator could be observed. The system appears to be suitable for verifying the need for occlusal adjustment. However, improvements concerning the hardware and software are necessary.

Bite Force↗
PubMed1992

Non-cast titanium restorations in fixed prosthodontics.

The problems encountered in casting titanium in dentistry have not been completely resolved. The Procera system forms crowns by means of a combination of spark-erosion and milling. The accuracy of fit was examined before and after ceramic veneering both in vitro and in vivo. Before veneering, on conical surfaces space widths were approximately 53 microns in vitro and 69 microns in vivo. At shoulders and occlusal surfaces, spaces of about 430 microns were measured in vitro and of about 500 microns were measured in vivo. After ceramic veneering, slight increases in space widths could be observed. The metal-ceramic compound was tested by the 3-point bending test (DIN) and the bending test (ISO). The DIN test was satisfactory, but not the ISO test. It is concluded that titanium crowns processed by the Procera System are suitable for clinical usage, if the space widths at shoulders and the occlusal surface and the special requirements of tooth preparation are taken into account.

Ceramics↗