PubMed Health⌕ Search

Biomedical subjects

N Hofmann

Publications and source records attributed to N Hofmann.

At least 19 recordsLinked to original sources
PubMed2006

Color Doppler indices of renal allografts depend on vascular stiffness of the transplant recipients.

A resistance index (RI) of 0.8 or higher was shown to be a strong predictor of kidney allograft and patient survival. Uncertainties persist since the intrarenal RI is closely associated with the vascular stiffness of the allograft recipient. To clarify the diagnostic value of RI further, we analyzed parameters of vascular stiffness of the recipient and intrarenal RI of the renal allograft. In a prospective study laboratory and clinical parameters, pulse wave velocity (PWV), intima media thickness (IMT) and RI were obtained in 76 kidney allograft patients. We found that the RI values significantly correlated with the PWV (p < 0.05) and the recipients age (p < 0.01) but not with the donor age and renal function. Using multiple regression analysis recipient age, PWV, pulse pressure (PP) and IMT were identified as independent factors influencing RI values. For a more correct interpretation of the RI values in renal allografts parameters of vascular stiffness such as IMT, PP or PWV should be included.

Adult↗
PubMed2005

[Locoregional anesthesia and coagulation inhibitors. Recommendations of the Task Force on Perioperative Coagulation of the Austrian Society for Anesthesiology and Intensive Care Medicine].

More efficacious anticoagulant and antiplatelet agents have been introduced in vascular medicine and in the prevention of perioperative venous thromboembolisms. Patient management should be guided by familiarity with the pharmacology of coagulation-altering drugs and by consensus statements. The present paper reviews recommendations from the Austrian Task Force for Perioperative Coagulation which are based on thorough evaluation of the available pharmacological information and case reports. The consensus statement focuses on neuraxial and peripheral techniques and is designed to encourage safe and quality patient care.

Anesthesia, Conduction↗
PubMed2001

Exogenous antigen containing perivascular phagocytes induce a non-encephalitogenic extravasation of primed lymphocytes.

Recent evidence suggests that T-lymphocyte extravasation and CNS-parenchymal infiltration during autoimmune disease might be regulated by antigen-presenting (ED2(+)) cerebral/spinal perivascular phagocytes (CPP/SPP). Since the massive erythrocytic and leukocytic infiltrates in the CNS of rats with experimental allergic encephalomyelitis do not allow a precise differentiation between CPP/SPP and the invading cells in the Virchow-Robin space, we developed a new immune-response model whereby the extravasation of T-lymphocytes was not followed by other blood cells. Adult Lewis rats were sensitized to horseradish peroxidase (HRP). Subsequent intracerebroventricular (i.c.v.) injections of HRP and/or Fluoro-Emerald (FE) served to: (1) challenge the primed T-lymphocytes and (2) label the CPP/SPP for additional immunocytochemical analysis. We found that 24 h and 3 days after single, double, or triple antigen boosting T-lymphocytes (R73(+), W3/25(+), OX50(+)) entered the Virchow-Robin space but did not break through the astrocytic glia limitans. Instead they adhered to HRP-containing activated CPP/SPP (mabs OX-6(+), SILK6(+), CD40(+), CD80(+), CD86(+)). This selective contact was mediated neither by cell adhesion molecules (P-selectin, ICAM-1, VCAM-1), nor promoted by chemokine receptors (CCR1, CCR5) or chemokines (monocyte chemoattractant protein (MCP)-1, MIP-1alpha, MIP-1beta, RANTES). This non-inflammatory, but antigen-dependent lymphocyte extravasation provides optimal conditions to further study the CNS immune response.

Animals↗
PubMed2001

Comparison of photo-activation versus chemical or dual-curing of resin-based luting cements regarding flexural strength, modulus and surface hardness.

This study investigated the efficiency of chemical activation of dual-cure resin-based luting cements as compared with light- and dual-curing. Curing was performed by (i) mixing base and catalyst without subsequent irradiation (chemical curing=CC), (ii) mixing base and catalyst with direct irradiation (dual-cure=DC) or with (iii) irradiation through 2.5 mm of leucite-reinforced glass-ceramics (IPS Empress, Ivoclar) (dual-cure through porcelain=DCtP), (iv) using only the base paste with direct irradiation (light-curing=LC) or with (v) irradiation through porcelain (light-curing through porcelain=LCtP). Specimens of four fine-hybrid DC resin composites and one self-cure hybrid resin composite (only CC) were prepared and tested after 24 h for flexural strength, modulus of elasticity (ISO 4049) and surface hardness (Vickers). For all materials and parameters, dual-curing produced higher values than LC, even when irradiation was performed through porcelain. Following self-curing without photo-activation, flexural strength was 68.9-85.9%, the modulus 59.2-94.5% and Vickers hardness 86.1-101.4% of the corresponding values obtained by dual-curing with direct irradiation. Light-curing through porcelain as compared with direct irradiation reduced the values for most parameters and materials. In contrast, dual-curing maintained flexural strength for all, the modulus for three and the hardness for one of the materials. The mechanical properties of the self-curing resin cement ranged between those of the DC materials.

Aluminum Silicates↗
PubMed2001

[In vivo study of small class II composite fillings].

This clinical trial aimed at studying the medium term performance in routine clinical practice of drop-shaped Class II resin composite restorations. 111 preparations were completed with the Sonicsys micro-tips (KaVo) and filled with either of two light-cured composites (Tetric Flow, Tetric Ceram, Vivadent, Schaan, Liechtenstein) by 11 dentists in a university clinic. The restorations were evaluated after half a year and then annually, using the US Public Health Service criteria. After one to three years of service nearly all restorations were clinically successful and acceptable for continued use. In four cases, incomplete caries excavation was the cause of failure. We conclude that the drop-shaped Class-II-resin composite restoration should be considered a routine operative treatment for small proximal lesions in posterior teeth.

Adult↗
PubMed2001

[In vitro study of marginal quality of small approximal composite fillings].

The aim of the study was to compare different preparation methods and filling techniques for class II microcavities in vitro. The following methods were evaluated: Sonicsys halftorpedo, Sonicsys halfsphere, Sonicsys approx, Siplus, Piezo cavity system and rotating finishing bur. Every cavity type was obturated with a flowable (Tetric flow) and with a hybrid composite (Tetric ceram). One group consisted of prefabricated ceramic inlays (Sonicsys approx) and one group was filled with a three-site light curing technique. This resulted in 128 composite fillings. The evaluation of the quality of the margins under the SEM demonstrated a statistically significant higher percentage of perfect margins for Siplus compared with the PCS-System (88% versus 58% perfect margins). Marginal adaptation before and after thermocycling demonstrated the following results: Bewelled margins showed in general better adaptation than box-shaped cavities. Similar results were found for normal and flowable composites. Microcavities with occlusal access prepared with the sonicsys halfsphere showed in general better marginal adaptation in comparison to the other methods tested. It was concluded that simple obturation techniques can lead to a stable adaptation of the margins.

Composite Resins↗
PubMed2001

[A retrospective in vivo study of Sonicsys approx restorations].

The purpose of this retrospective study was to determine the longevity and quality of Class II resin composite restorations with Sonicsys approx inserts placed in private practice. In 79 patients 213 composite restorations with margins in enamel and in dentin were evaluated clinically using a modified version of established USPHS-Criteria. The mean time in clinical service was 18+-8 months. The majority of the restorations investigated were rated as "good" (Alpha) or "clinically acceptable" (Bravo). In more than 90% sufficient proximal contact points were evaluated. Seven restorations had no contact to their adjacent tooth. Only one failed after an average period of 18 months in clinical service because of loss of the ceramic insert and was replaced. It is concluded that the composite restoration in combination with Sonicsys insert is an appropriate system for the restoration of Class II lesions in premolar and permanent molar teeth.

Ceramics↗
PubMed2000

Comparison between a plasma arc light source and conventional halogen curing units regarding flexural strength, modulus, and hardness of photoactivated resin composites.

The plasma arc curing light Apollo 95 E (DMDS) is compared to conventional curing lights of different radiation intensities (Vivalux, Vivadent, 250 mW/cm2; Spectrum, DeTrey, 550 mW/cm2; Translux CL, Kulzer, 950 mW/cm2). For this purpose, photoactivated resin composites were irradiated using the respective curing lights and tested for flexural strength, modulus of elasticity (ISO 4049), and hardness (Vickers, Knoop) 24 h after curing. For the hybrid composites containing only camphoroquinone (CQ) as a photoinitiator (Herculite XRV, Kerr; Z100, 3 M), flexural strength, modulus of elasticity, and surface hardness after plasma curing with two cycles of 3 s or with the step-curing mode were not significantly lower than after 40 s of irradiation using the high energy (Translux CL) or medium energy conventional light (Spectrum). However, irradiation by only one cycle of 3 s failed to produce adequate mechanical properties. Similar results were observed for the surface hardness of the CQ containing microfilled composite (Silux Plus, 3 M), whereas flexural strength and modulus of elasticity after plasma curing only reached the level of the weak conventional light (Vivalux). For the hybrid composites containing both CQ and photoinitiators absorbing at shorter wavelengths (370-450 nm) (Solitaire, Kulzer; Definite, Degussa), plasma curing produced inferior properties mechanical than conventional curing; only the flexural strength of Solitaire and the Vickers hardness of Definite reached levels not significantly lower than those observed for the weak conventional light (Vivalux). The suitability of plasma arc curing for different resin composites depends on which photoinitiators they contain.

Composite Resins↗
PubMed1999

Understanding the neuropsychiatric symptoms of Huntington's disease.

Huntington's disease (HD) is a neurodegenerative process that is manifest as deterioration in a person's motor control, cognition and emotional stability. Emotional instability is reflected through a variety of symptoms such as personality change, anxiety and irritability. These symptoms are complex and often poorly understood. Changes in the caudate are thought to contribute to psychiatric alterations seen in HD patients. An understanding of common psychiatric disorders seen in HD allows nurses to develop appropriate interventions.

Cognition Disorders↗
PubMed1998

The effect of glass ionomer cement or composite resin bases on restoration of cuspal stiffness of endodontically treated premolars in vitro.

The purpose of the present study was to decide whether composite resin or conventional glass ionomer cement should be preferred as a base material in endodontically treated premolars. Twelve extracted human maxillary premolars were mounted in a universal testing machine at a 35 degrees angle. Cuspal stiffness was determined by applying a load of 75 N to the buccal cusp and recording the displacement of the cusp using inductive displacement transducers. In the same teeth, different cavity preparations and restorations were performed sequentially. Standard MOD cavities were enlarged to allow endodontic access. In addition, the cusps were undermined. Half of the teeth were restored to the level of the previous shallow cavities using conventional glass ionomer cement (Ketac Fil), in the rest of the teeth dentine bonding agent (Syntac) and composite resin (Tetric) were used instead. Finally, composite resin fillings (Tetric) were placed. All restorations were removed and the experiments were repeated twice. For each replication, the assignment of the base materials to the experimental groups was reversed, and ceramic inlays (Empress) were used as final restorations for the last replication. Improvement of cuspal stiffness achieved by conventional glass ionomer bases was very small, whereas composite resin bases increased cuspal stability by more than a factor of two. After placement of the final restorations, however, there was no longer a difference between teeth with different base materials. Nevertheless, composite resin bases might be preferred for two reasons. Firstly, deterioration of adhesive restorations will probably start at the cavosurface margins. The incidence of margin gaps, however, will not only compromise marginal seal but also the stabilizing effect of the restoration. In this situation, the resin base may still stabilize the tooth. Moreover, resin bases may reduce the risk of cusp fracture during the time between cavity preparation and the insertion of adhesive inlays.

Aluminum Silicates↗
PubMed1993

Effect of storage media on microleakage of five dentin bonding agents.

The objective of this study was to investigate the effect of different storage media on microleakage at the gingival margin of mixed Class V composite restorations. Human molars were either used immediately after extraction (control group) or after a 3-4 wk storage period in 1% chloramine, 70% ethanol, 10% formalin, or 0.1% thymol. Class V cavities with cervical margins in cementum or dentin were prepared and restored with a microfill composite using five different dentin bonding agents. After thermocycling (1440 x from 5 degrees C to 55 degrees C) and basic fuchsin staining, the depth of dye penetration at the gingival margins was determined and ranked on a scale of 0 to 4. Class V restorations in teeth stored in formalin showed significantly less microleakage (mean leakage score, MLS = 1.7) than restorations in freshly extracted teeth (control group; MLS = 3.1). Microleakage scores in teeth stored in chloramine (MLS = 2.7), ethanol (MLS = 3.0) or thymol (MLS = 3.2) were not significantly different from the microleakage scores in the control group. The improvement of in vitro efficacy of dentin bonding agents when using extracted teeth stored in formalin is probably a result of collagen cross-linking by formaldehyde. Since such an alteration of the dentin does not reflect the condition of the substrate in vivo, extracted teeth assigned for in vitro evaluation of dentin bonding agents should not be stored in formalin. In teeth stored in 1% chloramine, the sums of ranks and the rank orders of the dentin bonding agents were comparable to those in freshly extracted teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

[The surface conditioning of pressed ceramics and its effect on the bond strength to composites].

After removal of the investment material, unpolished surfaces of pressed glass ceramics (Empress) are covered by a layer containing magnesium and phosphorus. This layer most likely results from the contact with the investment material during pressing. Following short-time conditioning with 5% HF-gel the superficial layer stays amorphous. After etching for 120 s most of the surface layer is removed revealing the fine grained etching pattern characteristic for this type of ceramics. Shear strength of composite luted to unetched pressed ceramic samples was rather low. After etching for 60 s bond strength was considerably higher, but only following 120 s of etching shear strength reached a level comparable to that of ground pressed samples and ground ingots after 60 s of etching. Since mechanical removal of the surface layer by grinding is not recommended, pressed glass ceramics should be etched for 120 s or longer to achieve an optimal bond strength to the luting composite.

Acid Etching, Dental↗
PubMed1992

[The facial profile and personality picture in children].

Facial skeletal malformations may not only lead to impaired function, but also diminish psychosocial well-being. Negative social experiences often arise from stereotyped character judgments such as those connected with the profile of the jaw. In this study, 146 orthodontic patients aged between nine and 14 years and student control subjects judged silhouettes of typical Angle class I, II/1 and III profiles on the basis of semantic differential and sociometric choice techniques. Moreover, the satisfaction of the subjects with the appearance of their heads and bodies, as well as their self-perceived personalities, were assessed with the aid of psychological inventories. Class II/1 profiles were characterised as rather shy, reserved, and melancholic, while to class III profiles were attributed reduced social acceptance and less popularity at school. In general, judgement of the silhouette profiles proved to be independent of the judge's own profile. Thus, the existence of trait stereotypes vis-á-vis class II/1 and class III profiles can be confirmed experimentally in children, too. The impact of social stereotypes on psychological well-being, however, is likely to be modified by numerous factors, in particular by social interaction.

Adolescent↗
PubMed1991

Use of aniline blue to assess chromatin condensation in morphologically normal spermatozoa in normal and infertile men.

Chromatin condensation is vital for the function of the spermatozoon as the motile carrier of the paternal genome. The degree of condensation can be shown with the aid of acidic aniline blue staining, which is able to discriminate between lysine-rich histones and arginine- and cysteine-rich protamines. Using this technique and employing the Düsseldorf classification of sperm morphology in cases of disturbance of spermatogenesis, it was demonstrated that chromatin condensation is impaired not only in malformed but also in morphologically normal spermatozoa. Among morphologically normal spermatozoa, the percentages of spermatozoa with chromatin condensation disturbances increase in patients with different patterns of sperm malformation, if compared with patients with normozoospermia.

Aniline Compounds↗
PubMed1990

[Preparation and insertion of computer-designed ceramic inlays].

The CEREC-system allows the production and insertion of ceramic inlays chairside in one visit. For this purpose an optical impression of the cavity is made, the inlay is designed on the computer screen and ground from a ceramic bloc. The inlay is bonded to the tooth using acid etch technique and a luting composite. Finally occlusal adjustment is performed. The technical prerequisites and the clinical procedure are presented and discussed in comparison to other tooth coloured inlay systems.

Dental Cavity Preparation↗
PubMed1990

[Shear bond strength between composite inlay and luting composite resin].

The shear bond strength between composite inlay materials and luting composite resins was measured under different storage conditions and using different finishing techniques. The initial shear bond strength was distinctly higher with light-cured composites subjected to secondary light and heat cure (56.7-81.1 MPa) than with a heat- and pressure-cured material, where appreciable bond strength was achieved only after sandblasting of the composite surface (18.8 MPa). In general, water storage of the samples for 30 days with intermittent thermocycling adversely affected the bond strength. The influence of secondary light and heat curing on the bond strength of primarily light-cured composites was highly dependent on the material used.

Composite Resins↗
PubMed1990

[Occlusal margin quality of Cerec-inlays several months after insertion].

The quality of the occlusal margins of 58 computer-machined ceramic inlays (Cerec) was examined by SEM. The adhesion of the luting composite to enamel and to the inlay appeared more of less stable. However, the wear of the composites was substantial and more pronounced in Brilliant and in Microfill pontic C than it was in Heliomolar.

Adult↗