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S Ruf

Publications and source records attributed to S Ruf.

At least 19 recordsLinked to original sources
PubMed2006

[Optimal time for treatment with the Herbst appliance].

This article endeavours to answer the question of whether treatment at an early or a later age is the ideal time for Herbst therapy. We discuss this topic by summarizing and evaluating the short and long-term effects of the Herbst appliance on the dentofacial complex. We place special emphasis on treatment outcomes in relation to the patient's somatic and skeletal maturity at the time of therapy. We also address the long-term stability of the treatment results. The available knowledge in the literature demonstrates that the ideal period for Herbst treatment is in the permanent dentition at or just after the peak of pubertal growth.

Adolescent↗
PubMed2005

Stress, burnout and health in the clinical period of dental education.

The study examined the extent of stress, burnout and health problems experienced by fourth and fifth year dental students from the three universities of Dresden, Freiburg and Bern. The objectives of the study were to: (i) identify frequent sources of stress and to report the prevalence rates of burnout and health problems in dental students, (ii) determine the rate of students suffering from severe burnout symptoms and (iii) identify stress factors related to the burnout symptoms of emotional exhaustion and depersonalization. A total of 161 dental students from Dresden, Freiburg and Bern participated in the study. They completed the Psychosocial Stress Inventory, the Maslach Burnout Inventory and the Health Survey Questionnaire. Frequent sources of stress were limitation of leisure time, examination anxiety and the transition stress that was related to the adaptation to the demands of the clinical phase of dental education. Few differences existed between the students of the fourth and the fifth study year. Study-related stress was lowest in Bern and considerably higher in Dresden. Differences of mean levels of burnout symptoms were found only for the burnout dimension of emotional exhaustion. Students from Dresden and Freiburg were more emotionally exhausted than students from Bern, students from Dresden also reported more health problems than students from Bern or Freiburg. Ten per cent of the dental students suffered from severe emotional exhaustion, 17% complained about a severe lack of accomplishment and 28% reported severe depersonalization symptoms. Forty-four per cent of the variance of emotional exhaustion was explained by study-related factors such as lack of leisure time, examination anxiety and transition stress. The only predictor of depersonalization was a lack of social integration, accounting for 3% of the variance. A lack of social integration may be an indicator of low social competence which may cause difficulties in dealing with patients adequately and therefore result in depersonalization. The results indicate a need to identify the group of students who may have insufficient social skills for dealing adequately with the patients, and to train them accordingly.

Adult↗
PubMed2002

[Diagnosis and therapy of necrotizing fasciitis].

Necrotizing fasciitis is a soft tissue infection with a lethality ranging up to 80%. Infection causes the activation of interleukin, tumor necrosis factor alpha, and gamma-interferon through a triggering mechanism. This results in a capillary thrombosis with necrosis of the fascia, cutis, and subcutis. The patient's history often reveals a triggering event in the form of a recent minimal trauma or operative procedure. In a fulminant necrotizing fasciitis, the development of sepsis with consecutive multiple-organ failure mainly determines the outcome of the disease. Diagnosis is made initially upon clinical findings with a rapid progression of the disease and confirmed later by histologic and microbiologic findings. Radical surgical debridement within the first 24 h with postoperative treatment in an intensive care unit represents the cornerstone of therapy. Between January 1992 and March 2001, we treated 15 patients with necrotizing fasciitis. Lethality was 33%. There was a significant correlation between risk factors (present in 86% of the patients) and morbidity. Diagnosis and therapy should be performed by an experienced surgeon. In this contribution, we discuss the most important criteria that lead to the diagnosis and the therapeutic consequences.

Adult↗
PubMed2001

[Timing of soft tissue reconstruction in severe crush injury of the upper extremity].

Complex injuries of the distal forearm and the hand by industrial machines often require extensive reconstructive procedures. Crush injuries with soft tissue damage extending over the limits of visible injury require a special approach. Large soft tissue defects often have to be covered by extensive flap procedures. The optimum point of time for plastic reconstruction is an essential question and represents a controversial issue in the literature. To be able to compare different patient cohorts in the future, we classify crush injuries into five clinically relevant categories. In the course of this review article, three different cases of severe crush injuries of the upper extremity are representatively discussed. Two patients were reconstructed in a secondary procedure, one patient in the acute phase. Definite coverage of soft tissue defects in severe crush injuries should be performed secondarily after 5-7 days since the extent of damage in this special form of trauma can often only be judged after a few days and the reconstruction of bones, vessels and tendons is completed.

Accidents, Occupational↗
PubMed2001

Stable genetic transformation of tomato plastids and expression of a foreign protein in fruit.

Transgenic chloroplasts offer unique advantages in plant biotechnology, including high-level foreign protein expression, absence of epigenetic effects, and gene containment due to the lack of transgene transmission through pollen. However, broad application of plastid genome engineering in biotechnology has been largely hampered by both the lack of chloroplast transformation systems for major crop plants and the usually low plastid gene expression levels in nongreen tissues such as fruits, tubers, and other storage organs. Here we describe the development of a plastid transformation system for tomato, Lycopersicon esculentum. This is the first report on the generation of fertile transplastomic plants in a food crop with an edible fruit. We show that chromoplasts in the tomato fruit express the transgene to approximately 50% of the expression levels in leaf chloroplasts. Given the generally very high foreign protein accumulation rates that can be achieved in transgenic chloroplasts (>40% of the total soluble protein), this system paves the way to efficient production of edible vaccines, pharmaceuticals, and antibodies in tomato.

Biotechnology↗
PubMed2001

Effective condylar growth and chin position changes in activator treatment: a cephalometric roentgenographic study.

Effective condylar growth (a summation of condylar remodeling, glenoid fossa remodeling, and condylar position changes within the fossa) and its influence on the position of the chin was analyzed in 40 class II, division I malocclusions treated successfully with activators. Additionally, the amount of mandibular rotation was assessed. Lateral head films in habitual occlusion from before and after an average treatment period of 2.6 years were evaluated. The Bolton Standards (32 untreated individuals with ideal occlusion) served as controls. Two different treatment effects were evaluated: overall growth change and treatment effects (overall growth changes minus age-related Bolton values). In comparison with the Bolton group, the activator patients exhibited an increase in the amount of vertical effective condylar growth (3.0 mm; P < .001), a decrease in the amount of sagittal effective condylar growth (0.6 mm; P < .05), and an increase in the amount of vertical development of the chin (1.8 mm; P < .001). No group differences could be found for sagittal development of the chin. In the Bolton group, the mandible rotated posteriorly, and in the activator group it rotated anteriorly (2.7 degrees; P < .001). The present investigation revealed that effective condylar growth can be increased and the chin position can be changed by activator treatment. Thus activator treatment induces skeletal changes, although not always in the desired (sagittal) therapeutic direction.

Activator Appliances↗
PubMed2001

[Coincidence of Lipoma and Liposarcoma of the Right Hand in an 84-Year-Old Patient: A Case Report].

Summary. We report the case of an 84-year-old patient presenting with a painless tumor between the thumb and the index finger. MRI showed a clearly defined tumor of the thenar eminence with a centrally localized more solid structure. There was a signal enhancement after intravenous administration of contrast medium. We performed a local resection of the tumor. Histologically, we found a lipoma with a centrally localized liposarcoma. We discuss the rare case of malignant transformation of a lipoma. In long-standing large lipomas we suggest regular controls by MR imaging.

Aged↗
PubMed2001

[Indirect MR Arthrography of the wrist in the diagnosis of TFCC-Lesions].

PURPOSE: The objective of this prospective study was to assess the value of the indirect MR arthrography (MR-AR) of the wrist in the detection of lesions of the TFCC. MATERIAL AND METHODS: Indirect MR-AR was performed in 45 patients (23 f/22 m) with unclear ulnar wrist pain. After i. v. injection of 0.1 mmol/kg Gd-DTPA and after a motion-phase of the wrist (15 minutes) MRI was performed in a coronal plane. We used a STIR-, a fatsaturated (fs) T1-SE and a 3D-DESS sequence. The images were evaluated by two radiologists using a consensus score. The lesions were assigned to the system of Palmer and correlated with arthroscopy. RESULTS: Indirect MR-AR showed in 35 of 45 patients a lesion of the TFCC, but arthroscopy only revealed a defect in 32 cases. This means three false positive but no false negative assessments by MRI. Using this MRI protocol sensitivity and specificity in the detection of TFCC lesions were calculated as 100 % and 77 %. The accuracy was 93 %. Small degenerative changes of the fibres were most common (Palmer type II A). In trauma patients the ligaments usually showed tears near the insertion at the ulna (Palmer type I B). The sensitivity and specificity was 88 % and 95 % for evaluation of the scapho-lunate (SL) ligament, the accuracy was 93 %. Arthroscopy and MRI did not diagnose any rupture of the lunate-triquetral (LT) ligament. CONCLUSION: Indirect MR-AR is a non-invasive method with a high sensitivity in the evaluation of the TFCC and associated injuries. Therefore, it is an excellent screening procedure to assess the indication for therapeutic arthroscopy.

Adolescent↗
PubMed2000

A small chloroplast-encoded protein as a novel architectural component of the light-harvesting antenna.

A small conserved open reading frame in the plastid genome, ycf9, encodes a putative membrane protein of 62 amino acids. To determine the function of this reading frame we have constructed a knockout allele for targeted disruption of ycf9. This allele was introduced into the tobacco plastid genome by biolistic transformation to replace the wild-type ycf9 allele. Homoplasmic ycf9 knockout plants displayed no phenotype under normal growth conditions. However, under low light conditions, their growth rate was significantly reduced as compared with the wild-type, due to a lowered efficiency of the light reaction of photosynthesis. We show that this phenotype is caused by the deficiency in a pigment-protein complex of the light-harvesting antenna of photosystem II and hence by a reduced efficiency of photon capture when light availability is limiting. Our results indicate that, in contrast to the current view, light-harvesting complexes do not only consist of the classical pigment-binding proteins, but may contain small structural subunits in addition. These subunits appear to be crucial architectural factors for the assembly and/or maintenance of stable light-harvesting complexes.

Amino Acid Sequence↗
PubMed2000

Does bite-jumping damage the TMJ? A prospective longitudinal clinical and MRI study of Herbst patients.

The aim of this prospective longitudinal study of 62 consecutively treated Class II malocclusions was to determine whether bite-jumping causes temporomandibular disorders (TMD). The function of the temporomandibular joint (TMJ) was assessed anamnestically, clinically, and by means of magnetic resonance images (MRIs) taken before (T1), after (T2), and 1 year after (T3) Herbst treatment. Average treatment time with the Herbst appliance was 7.2 months. In all subjects, Herbst treatment resulted in a Class I or overcorrected Class I dental arch relationship. Thereafter, treatment was continued with a multibracket appliance. The condyle was positioned significantly forward during treatment but returned to its original position after removal of the Herbst appliance. A temporary capsulitis of the inferior stratum of the posterior attachment was induced during treatment. Over the entire observation period from before treatment to 1 year after treatment, bite-jumping with the Herbst appliance: (1) did not result in any muscular TMD; (2) reduced the prevalence of capsulitis and structural condylar bony changes; (3) did not induce disc displacement in subjects with a physiologic pretreatment disc position; (4) resulted in a stable repositioning of the disc in subjects with a pretreatment partial disc displacement with reduction; and (5) could not recapture the disc in subjects with a pretreatment total disc displacement with or without reduction. A pretreatment total disc displacement with or without reduction did not, however, seem to be a contraindication for Herbst treatment. In conclusion, bite-jumping using the Herbst appliance does not have a deleterious effect on TMJ function and does not induce TMD on a short-term basis.

Adolescent↗
PubMed2000

The two largest chloroplast genome-encoded open reading frames of higher plants are essential genes.

The chloroplast genomes of most higher plants contain two giant open reading frames designated ycf1 and ycf2. In tobacco, ycf1 potentially specifies a protein of 1901 amino acids. The putative gene product of the ycf2 reading frame is a protein of 2280 amino acids. In an attempt to determine the functions of ycf1 and ycf2, we have constructed several mutant alleles for targeted disruption and/or deletion of these two reading frames. The mutant alleles were introduced into the tobacco plastid genome by biolistic chloroplast transformation to replace the corresponding wild-type alleles by homologous recombination. Chloroplast transformants were obtained for all constructs and tested for their homoplastomic state. We report here that all transformed lines remained heteroplastomic even after repeated cycles of regeneration under high selective pressure. A balanced selection was observed in the presence of the antibiotic spectinomycin, resulting in maintenance of a fairly constant ratio of wild-type versus transformed genome copies. Upon removal of the antibiotic and therewith release of the selective pressure, sorting out towards the wild-type plastid genome occurred in all transplastomic lines. These findings suggest that ycf1 and ycf2 are functional genes and encode products that are essential for cell survival. The two reading frames are thus the first higher plant chloroplast genes identified as being indispensable.

Chloroplasts↗
PubMed2000

Cephalometric assessment of sagittal jaw base relationship prior to orthognathic surgery: the role of anterior cranial base inclination.

In a cephalometric study, 71 presurgical lateral radiographs of patients suffering from malpositions of 1 or both jaws were analyzed to assess the influence of cranial base inclination on anteroposterior cephalometric angles. Angles SNA and SNB, as well as the angle between sella-nasion (SN) and Frankfort horizontal (FH), were measured. To verify the true sagittal position of the jaws, SNA and SNB were related to a corrected normal anterior cranial base inclination (mSNA, mSNB). Two geometric models were calculated and examined. The application of the first and second models for SNA and SNB resulted in different estimations of the sagittal jaw position in 46% and 38% of the presented patients, respectively. Linear regression analysis demonstrates that FH may not be substituted for SN as a reference line in anteroposterior measurements, but underlines that a correction with regard to anterior cranial base inclination is beneficial. According to the results of the second model, the most valuable reference line appears to be located approximately halfway between SN and FH. Considering the frequent coincidence of jaw malposition and cranial base dysmorphia, cranial base-related cephalometric parameters should be interpreted carefully.

Adolescent↗
PubMed1999

Targeted inactivation of the smallest plastid genome-encoded open reading frame reveals a novel and essential subunit of the cytochrome b(6)f complex.

The smallest conserved open reading frame in the plastid genome, ycf6, potentially specifies a hydrophobic polypeptide of only 29 amino acids. In order to determine the function of this reading frame we have constructed a knockout allele for ycf6. This allele was introduced into the tobacco plastid genome by chloroplast transformation to replace the wild-type ycf6 allele. Homoplasmic Deltaycf6 plants display a photosynthetically incompetent phenotype. Whereas the two photosystems are intact and physiologically active, we found that the electron transfer from photosystem II to photosystem I is interrupted in Deltaycf6 plants. Molecular analyses revealed that this block is caused by the complete absence of the cytochrome b(6)f complex, the redox-coupling complex that interconnects the two photosystems. Analysis of purified cytochrome b(6)f complex by mass spectroscopy revealed the presence of a protein that has exactly the molecular mass calculated for the Ycf6 protein. This suggests that Ycf6 is a genuine subunit of the cytochrome b(6)f complex, which plays a crucial role in complex assembly and/or stability. We therefore propose to rename the ycf6 reading frame petN.

Amino Acid Sequence↗
PubMed1999

Mandibular articular disk position changes during Herbst treatment: a prospective longitudinal MRI study.

The aim of this prospective longitudinal study of 15 consecutively treated Class II malocclusions was to assess any possible changes in the relative position of the articular disk to the condyle during different phases of Herbst therapy. Using a disk position index, parasagittal MRIs (central, medial and lateral slices) of the right and left TMJ were analyzed at five occasions: before Herbst treatment (T1), at start of treatment when the appliance was placed (T2), after 6 weeks of treatment (T3), after 13 weeks of treatment (T4), and after 7 months of treatment when the appliance was removed (T5). In all subjects Herbst treatment resulted in Class I or overcorrected Class I dental arch relationships. Condyle position was on average unchanged during Herbst treatment (T1 to T5). Before treatment (T1) the articular disk was in a slight protrusive position relative to the condyle. At start of treatment (T2) the mandible was advanced to an incisal edge to edge position. Because of the physiologic relative movement of disk and condyle on mandibular protrusion the disk attained a pronounced retrusive position. At the end of treatment (T5), the disk had almost returned to its original pretreatment position. In several cases, however, a slight retrusive disk position prevailed. In conclusion, Herbst treatment did not result in any adverse changes in articular disk position. On the contrary, the Herbst appliance could possibly be useful in the therapy of patients with anterior disk displacement.

Adolescent↗
PubMed1999

Temporomandibular joint remodeling in adolescents and young adults during Herbst treatment: A prospective longitudinal magnetic resonance imaging and cephalometric radiographic investigation.

The aim of this prospective study was to analyze and compare the temporomandibular joint adaptive mechanisms in 25 adolescent and 14 young adult Class II malocclusions treated with the Herbst appliance. Temporomandibular joint remodeling was analyzed by magnetic resonance imaging. In each subject, 4 magnetic resonance images of both temporomandibular joints were available: before treatment, at the start of treatment (when the Herbst appliance was placed), during treatment (6 to 12 weeks after appliance placement), and after treatment (when the appliance was removed). Furthermore, effective temporomandibular joint changes (the sum of condylar remodeling, fossa remodeling, and condyle-fossa relationship changes) were analyzed with the aid of lateral cephalometric radiographs from before and after treatment. All subjects were treated to Class I or overcorrected Class I dental arch relationships, and their mandibles became significantly (P <.001) more prognathic. After 6 to 12 weeks of Herbst treatment, signs of condylar remodeling were seen at the posterosuperior border in 48 of the 50 adolescent condyles and in 26 of the 28 young adult condyles. Bilateral remodeling of the mandibular ramus could be detected in 1 adolescent and 2 young adult patients. Signs of glenoid fossa remodeling at the anterior surface of the postglenoid spine were noted in 36 adolescent and 22 young adult temporomandibular joints. Effective temporomandibular joint changes during treatment were more horizontally directed and larger in both adolescents and young adult patients treated with the Herbst appliance than in an untreated group of subjects with ideal occlusion (Bolton standards). The increase in mandibular prognathism accomplished by Herbst therapy in both adolescents and young adults seems, in particular, to be a result of condylar and glenoid fossa remodeling. Because the Herbst appliance is most successful in Class II patients also at the end of the growth period, the treatment method could be an alternative to orthognathic surgery in borderline skeletal Class II cases. Magnetic resonance imaging renders an excellent opportunity to visualize the temporomandibular joint remodeling growth processes.

Adaptation, Physiological↗
PubMed1999

The compensatory mechanism in high-angle malocclusions: a comparison of subjects in the mixed and permanent dentition.

Dentoskeletal morphology was assessed in 191 untreated and unselected children with a hyperdivergent (high-angle) mandibular plane (ML/NSL > or =40 degrees) by analyzing lateral roentgenographic cephalograms. The subjects were divided into mixed dentition and permanent dentition groups, and further divided into subgroups based on the amount of overbite (OB) as a measure of dentoalveolar compensation of jaw base hyperdivergency: OB < 0 mm (openbite) = insufficient/no compensation; OB 0 to 4 mm (normal overbite) = acceptable compensation; OB > 4 mm (deepbite) = overcompensation. Openbite was observed in 20% of the children, normal overbite in 50%, and deepbite in 30%. Skeletally, the deepbite mixed dentition group was characterized by a relatively posterior inclination of the maxilla, while the deepbite permanent dentition group had a relatively anterior inclination of the mandible. Dentoalveolar compensation was accomplished by relative increases in maxillary and mandibular anterior dentoalveolar heights in the mixed dentition group and by relative decreases in maxillary and mandibular posterior dentoalveolar heights in the permanent dentition. Positive overbite was found in the majority (80%) of children with high-angle morphology. Thus, mandibular hyperdivergency is frequently compensated for. Skeletal characteristics and dentoalveolar compensatory mechanisms differ with dental maturity and seem to be influenced by mouth breathing and other oral habits.

Age Factors↗
PubMed1999

Dentoskeletal effects and facial profile changes in young adults treated with the Herbst appliance.

This prospective Herbst study analyzed the sagittal dental and skeletal changes contributing to Class II correction in young adults. Additionally, the alteration in skeletal and soft tissue convexity occurring during treatment was assessed. Early adolescent subjects in the permanent dentition who had been treated with the Herbst appliance were used for comparison. Lateral headfilms from before and after an average treatment period of 8.5 months for the young adults and 7.1 months for the adolescents were evaluated. All adult and adolescent subjects were treated to either Class I or overcorrected Class I occlusal relationships. In both groups the improvement in sagittal incisor and molar relationships was achieved more by dental changes than by skeletal ones. The amount of skeletal change contributing to overjet and molar correction was smaller in the young adult group (22% and 25%, respectively) than in the early adolescent group (39% and 41%, respectively). Skeletal and soft tissue facial profile convexity was reduced in adults and adolescents. Facial profile improvement did not differ between the two groups. The results of this study revealed that the Herbst appliance is most effective in the treatment of Class II malocclusion in young adults. It is suggested that this treatment method could be an alternative to orthognathic surgery in borderline Class II cases.

Adolescent↗