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J Hoffmann

Publications and source records attributed to J Hoffmann.

At least 37 records · Page 2Linked to original sources
PubMed2005

CGRP release and c-fos expression within trigeminal nucleus caudalis of the rat following glyceryltrinitrate infusion.

Neuropeptide release and the expression of c-fos like immunoreactivity (c-fos LI) within trigeminal nucleus caudalis neurons (TNC) are activation markers of the trigeminal nerve system. Glyceryltrinitrate (GTN) is believed to stimulate the trigeminal nerve system, thereby causing headache. We examined the effects of a 30 min NO-donor infusion on CGRP release in jugular vein blood and c-fos LI within TNC of the rat. GTN (2 and 50 microg/kg/min) or NONOate infusion (25 nmol/kg/min) did not cause any CGRP release during and shortly after infusion, whereas administration of capsaicin resulted in strongly increased CGRP levels. GTN infusion (2 microg/kg/min for 30 min) did not lead to enhanced c-fos LI after 2 h and 4 h, whereas capsaicin infusion caused a time- and dose-dependent expression of c-fos LI within laminae I and II of the TNC. Surprisingly, GTN attenuated capsaicin-induced c-fos expression by 64%. The nitric oxide synthase (NOS) inhibitor L-NAME (5 and 50 mg/kg) reduced capsaicin-induced c-fos LI dose dependently (reduction by 13% and 59%). We conclude that GTN may lead to headaches by mechanisms independent of CGRP release from trigeminal nerve fibres. GTN doses comparable to those used in humans did not activate or sensitize the trigeminal nerve system. Both GTN and L-NAME reduced capsaicin-induced c-fos LI. This is most likely due to a feedback inhibition of nitric oxide synthases, which indicates that the c-fos response to capsaicin within TNC is mediated by NO dependent mechanisms.

Animals↗
PubMed2005

Expression of carbonic anhydrase 9 at the invasion front of gastric cancers.

BACKGROUND: Carbonic anhydrase IX (MN/Ca9) catalyses the reversible metabolism of carbon dioxide to carbonic acid and has also been linked to malignant transformation and hypoxia in various cancers. AIMS: To assess the expression and biological role of Ca9 in gastric cancer. METHODS: Using gastric cancer cell lines and tissues, we studied expression of Ca9 by western blot analysis, immunohistochemistry, and polymerase chain reaction. Biological changes after Ca9 transfection and after treatment with 5'-azadeoxycytidine were also analysed in cancer cell lines. RESULTS: Non-cancerous tissues strongly expressed Ca9 with membranous localisation. In contrast, Ca9 expression was frequently lost in gastric cancers (p<0.001). However, gastric cancers that retained Ca9 expression in cancer cells exhibited a shorter postoperative survival (p = 0.028). In vitro analysis revealed that loss of Ca9 expression in gastric cancer cell lines was restored after treatment with 5'-azadeoxycytidine and was associated with increased invasion (p<0.01). Moreover, AGS cells transfected with Ca9 exhibited significantly increased cell proliferation (p<0.05). CONCLUSIONS: A subgroup of gastric cancers retain Ca9 expression in cancer cells at the invasion front. While loss of Ca9 expression is regulated in part by methylation, re-expression of Ca9 is associated with increased invasion, supporting the hypothesis that increased Ca9 expression may contribute to invasion and thus advanced disease and tumour progression in a subset of gastric cancers.

Adult↗
PubMed2004

Three-dimensional (3D) and 4D color Doppler fetal echocardiography using spatio-temporal image correlation (STIC).

OBJECTIVE: Color Doppler echocardiography is used to visualize three transverse planes: the four-chamber, five-chamber, and three vessels and trachea views. Color Doppler spatio-temporal image correlation (STIC) is a new three-dimensional (3D) technique allowing the acquisition of a volume of data from the fetal heart that is displayed as a cineloop of a single cardiac cycle. The aim of the study was to examine the potential of color Doppler STIC to evaluate normal and abnormal fetal hearts. METHODS: This prospective study included 35 normal fetuses and 27 fetuses with congenital heart defects (CHD) examined between 18 and 35 weeks of gestation. Volume acquisition was achieved by initiating the image capture sequence from the transverse four-chamber view. Volumes were stored for later offline evaluation using a personal computer-based workstation in a multiplanar mode and as spatial volume rendering. RESULTS: Successful acquisition was possible in all 62 cases. The three planes could be demonstrated in 31/35 healthy fetuses and in 24/27 fetuses with CHD. Spatial volume rendering was attempted in 18 fetuses with CHD. In the four normal fetuses with inadequate visualization using color Doppler STIC, the region of interest was perpendicular to the ultrasound beam. In two fetuses with CHD inadequate visualization was related to an enlarged heart in late gestation, in which the entire cardiac volume could not be acquired. The third case was an 18-week fetus with complex CHD and transposed great vessels in which artifacts were related to confluent color signals as a result of low resolution in the reconstructed plane. CONCLUSIONS: STIC in combination with color Doppler ultrasound is a promising new tool for multiplanar and 3D/4D rendering of the fetal heart. Limitations may be found later in gestation in fetuses with large hearts and early in gestation as a result of low discrimination of signals. In addition, insonation perpendicular to the structure of interest does not image color Doppler signals and should be avoided during acquisition.

Cardiac Volume↗
PubMed2004

[Differential diagnosis of saccular aneurysms of the isthmus aortae: example of a penetrating atherosclerotic ulcer. Case-report and review of the literature].

Most aneurysms of the isthmus aortae, particularly those following thoracic trauma, are most likely to be diagnosed as acute dissecting or post-traumatic pseudoaneurysms. Furthermore, penetrating atherosclerotic ulcers in patients with atherosclerosis, congenital aneurysms such as ductus diverticulum and Kommerell's diverticulum, luetic aneurysms, and saccular aneurysms associated with Marfan's syndrome have to be included in the list of differential diagnoses. In view of the severe effect of any open thoracic surgical intervention, exact preoperative diagnosis is crucial. We report the case of a 73-year-old male patient who was accidentally diagnosed with an aneurysm of the atherosclerotic isthmus aortae. The aneurysm extended from the aorta to the dorsal site. The sacciform aneurysm (4.5 cm) was resected electively. Based upon localisation and pathomorphological findings, a penetrating ulcer was diagnosed. We also present a review of the current literature and give a survey of the differential diagnoses of aneurysms of the aortic isthmus: penetrating atherosclerotic ulcus, acute (traumatic) dissecting aneurysm, post-traumatic pseudoaneurysm, ductus diverticulum, Kommerell's diverticulum, syphilitic aneurysm, and sacciform aneurysm due to Marfan's syndrome.

Aged↗
PubMed2004

Lipoma of the breast: a diagnostic dilemma.

Lipoma of the breast often causes diagnostic and therapeutic uncertainty. Clinically it may be difficult to distinguish a lipoma from other conditions. Fine-needle aspiration cytology (FNAC) is often not helpful. Both mammography and ultrasound scanning are often negative. For the present study, 108 women with a clinical diagnosis of lipoma were enrolled prospectively. The clinical diagnosis of lipoma was found to be incorrect in 25.0% of these cases. Mammography and ultrasound revealed a lipoma in only 3.0% and 21.0%, respectively. FNAC revealed only fat cells in 74.0% of cases. In all, only 9 patients (11.4%) fulfilled the triple diagnostic criteria, theoretically making tumour excision mandatory in the remaining cases. Our proposal for management is for any clinical diagnosis of lipoma to be confirmed by either FNAC revealing fat cells or a core biopsy consistent with a lipoma. The mammogram and the ultrasound need not necessarily demonstrate a lipoma, but obviously must not show anything to raise the suspicion of malignancy at the site. If these criteria are met it is not necessary to excise the tumour.

Adult↗
PubMed2004

Biological effects of imidazolium ionic liquids with varying chain lengths in acute Vibrio fischeri and WST-1 cell viability assays.

Detailed biological studies of methyl- and some ethylimidazolium ionic liquids in luminescent bacteria as well as in the IPC-81 (leukemia cells) and C6 (glioma cells) rat cell lines are presented. Effective concentrations in these test systems are generally some orders of magnitude lower than effective concentrations [corrected] of the conventional solvents acetone, acetonitrile, methanol, and methyl t-butyl ether. No general influence of the anionic compound in the ionic liquids on toxicity could be found, although they seem to modulate toxicity in some cases. The clear influence of the alkyl chain length on toxicity was quantified by linear regression analysis. Alkyl chain length of the longer alkyl chain was varied from 3 to 10 carbon atoms. Consequences for a design of sustainable alternative solvents are briefly sketched.

Animals↗
PubMed2004

False-negative frozen section of sentinel lymph node biopsy for breast cancer.

A prospective study is presented of frozen section examinations (FS) performed in parallel with 265 consecutive sentinel lymph node procedures (SLNP) over a 20-month period. The final pathological study included immunohistochemistry (IHC) for keratin if the haematoxylin-eosin (HE)-stained section was tumour free. FS correctly identified node-positive or node-negative axillae in 235 cases. In 28 SLNPs the final examination gave a positive result not detected in the FS, resulting in reoperation. In 21 of these false-negative (FN) cases micrometastases (MIM) were present. There were no false-positive cases, but in two cases of lobular carcinoma the findings in the FS were equivocal, the final reports recording metastases in one but not in the other. Lobular carcinoma and other less common subtypes of carcinoma were overrepresented, ductal carcinoma not otherwise specified (NOS) being less likely to affect the FN findings.

Breast Neoplasms↗
PubMed2004

[Image-guided navigation for the control interstitial laser therapy of vascular malformations in the head and neck region].

Laser-induced interstitial thermal therapy (LITT) is a proven minimally invasive surgical technique for the treatment of haemangiomas and vascular malformations, and various tumours. The intra-lesion application of thermal energy destroys regional tissue. The percutaneous placement of the laser fibre for photocoagulation is done without the benefit of direct visual control. Image-data-based LITT was performed in patients (five procedures) with extensive venous malformations in the maxillofacial area. The system comprised a specially developed Nd:YAG laser fibre introducer set used in conjunction with fused high-resolution computed tomography, and magnetic resonance image-data--based surgical navigation. In all cases, follow-up examination clearly showed a diminishment in tumour volume, and all patients reported significant subjective improvement. The results suggest that navigation-guided LITT can be performed safely, preserving vital structures from collateral thermal damage.

Head and Neck Neoplasms↗
PubMed2003

Phase transitions and quantum effects in pore condensates: a path integral Monte Carlo study.

Lennard-Jones condensates in cylindrical pores are studied by path integral Monte Carlo simulations with particular emphasis on phase transitions and quantum effects. The pore diameter effect and the influence of the interaction strength between the cylinder wall and the adsorbate particles on the structures and the location of the phase boundaries is studied and the quantum effect on the phase diagram is quantified by path integral Monte Carlo simulations. In case of strong wall-particle interactions good qualitative agreement with recent experimental results for the freezing of Ar-pore condensates is found. Meniscus structures in the solid phase are obtained as well as unexpected condensate structures for the system with the lighter Ne-particles due to quantum delocalization effects. The quantum effect on the freezing temperature can be as large as 10% in these systems.

Journal Article↗
PubMed2003

[Hemangiomas and vascular malformations in the area of the head and neck].

The treatment of paediatric patients with extended vascular anomalies in the head and neck requires a multidisciplinary approach involving paediatricians, maxillofacial surgeons, dermatologists and radiologists. Therapeutic strategies are based on an internationally accepted classification of vascular anomalies, which distinguishes haemangiomas and vascular malformations. Whereas haemangiomas are endothelial proliferations, vascular malformations are considered to be developmental anomalies which are classified into high-flow or low-flow lesions and, according to their vascular channels, into capillary, lymphatic or venous malformations. In this review we present guidelines for the diagnostic assessment of paediatric patients with vascular anomalies in the head and neck region. The indications for treatment are discussed and therapeutic options are outlined.

Adolescent↗
PubMed2003

[Registration using three-dimensional laser surface scanning for navigation in oral and craniomaxillofacial surgery].

INTRODUCTION: Recent innovations in laser scanning technology provide a potentially useful tool for three-dimensional surface registration for image-guided surgery. The purpose of this study is to evaluate the clinical reliability of this technique in oral and maxillofacial surgical procedures using image-guided navigation. METHODS: In an experimental step, a stable anthropomorphic skull model with prelabeled markers was scanned and registered with laser surface scanning (z-touch, BrainLAB) and marker- based algorithms. The registration protocol was then repeated 25-times. Root mean square error (RMSE) and target difference values were compared for their suitability for this application. Twelve patients with different indications for oral and maxillofacial surgery were planned for image-guided surgery using a passive infrared surgical navigation system (VectorVision, BrainLAB). Preoperative computed tomography (CT) scans were carried out with newest 16-line multisclice CT-scanner (Siemens Somatom Sensation 16). The new markerless laser surface scanning technique was applied in all intraoperative patient registrations. Registration error was noted. The clinical application accuracy was determined for anatomical landmark localization deviation. RESULTS: In the experimental protocol a mean registration error (RMSE) or target difference of 1.3 (0.14) or 2.08 (0.49) mm for laser scanning and 0.38 (0.01) or 0.99 (0.15) mm for marker registration was found. The differences for RMSE and target localization were statistically significant (p < 0.005). Furthermore, a strong correlation between RMSE and target difference was found for laser scanning (r = 0.96) and marker registration (r = 0.95). During various clinical procedures involving oral and maxillofacial surgery, the overall error of the registration procedure determined as RMSE was 1.21 (0.34) mm. Intraoperatively, the mean clinical application accuracy was found to be 1.8 (0.5) mm. CONCLUSION: Three-dimensional laser surface scanning technique may be a interesting and useful approach to register the patient for image-guided procedures, particularly during oral and craniomaxillofacial surgery.

Cephalometry↗
PubMed2002

[Interdisciplinary concept for classification and treatment of vascular anomalies in the head and neck].

PURPOSE: In patients with extended vascular anomalies in the head and neck, therapeutic decisions may pose a challenge to maxillofacial surgeons, dermatologists, and interventional radiologists. We analyzed the value of an interdisciplinary classification and treatment concept. PATIENTS AND METHODS: The classification distinguishes hemangiomas and vascular malformations. Whereas hemangiomas are endothelial proliferations, vascular malformations are considered to be developmental anomalies, which are further classified into high-flow or low-flow lesions and according to the vascular channels into capillary, venous, or lymphatic malformations. Since 2000 we have provided interdisciplinary consultation for patients with vascular anomalies. In patients with hemangiomas and venous malformations, the clinical diagnosis is confirmed by color-coded duplex sonography and magnetic resonance imaging; angiography is performed as part of the treatment planning for patients with arteriovenous malformations. Patients with hemangiomas are treated surgically by cryosurgery or laser surgery or conservatively according to lesion size and behavior. In patients with venous malformations, percutaneous sclerotherapy is combined with surgical reduction; patients with arteriovenous malformations undergo transarterial embolization prior to surgical excision of the nidus. RESULTS: A total of 73 patients attended the interdisciplinary consultation. This group included 53 patients with facial hemangiomas, 7 with venous malformations, 2 with capillary malformations, 5 with lymphatic malformations, and 6 with high-flow arteriovenous malformations. CONCLUSIONS: The interdisciplinary protocol increases diagnostic accuracy and helps to establish individual treatment plans for patients with extended vascular anomalies.

Adolescent↗
PubMed2002

A new electrochemically graded hydroxyapatite coating for osteosynthetic implants promotes implant osteointegration in a rat model.

Hydroxyapatite (HAP) is widely used as an osteoconductive coating for orthopedic implants. So far standard coating methods like plasma spraying produce a relatively thick coating layer (>30 microm). In addition, the chemical structure of the HAP may be altered because of the heating throughout the coating process. This may have negative effects on the coating stability, implant fixation, and induction of bone formation. The relatively thick layer may detach from the implant with the risk of wear debris. In the present study the potential of a newly developed HAP coating of implants on osteointegration was investigated in a rat model. The coating method, based on an electrochemical process, is applied in a graded manner and results in a biodegradable HAP coating with a thickness of approximately 2 mum. Coated versus uncoated titanium Kirschner wires (1.4-mm diameter) were inserted into the medullary cavity of the right femora of 5-month old female Sprague Dawley rats (n=36) in a retrograde fashion. Throughout an experimental period of 2 months the osteointegration was traced radiologically. After this time the animals were sacrificed and the implant integration was tested biomechanically with the use of a push-out test. To analyze the bone-implant interface, histological sections (80 mum) were investigated with an image analyzing system. The biomechanical testing revealed a significantly higher implant fixation in the group treated with the HAP-coated implant (shear strength: 27.8 +/- 6.7 MPa) compared to control (shear strength: 8.08 +/- 3.4 MPa). The histological analyses demonstrated a better ingrowth of the implants in the HAP group with significantly more direct bone-implant contacts compared to the control group. The results demonstrate that the HAP coating promotes implant osteointegration in a rat model.

Animals↗
PubMed2002

Biotransformation of trichloroethene by pure bacterial cultures.

From natural samples 11 isolates able to remove trichloroethene (CCl2CHCl) from an aqueous environment were obtained which were capable of cometabolic degradation of CCl2CHCl by an enzyme system for phenol degradation. At an initial CCl2CHCl concentration of 1 mg/L, the resting cells of particular cultures degraded 33-94% CCl2CHCl during 1 d and their transformation capacity ranged from 0.3 to 3.1 mg CCl2CHCl per g organic fraction. An analysis of a mixed phenol-fed culture with an excellent trichloroethene-degrading ability found a markedly minority isolate represented in the consortium to be responsible for this property. This culture degraded CCl2CHCl even at a low inoculum concentration and attained a transformation capacity of 14.7 mg CCl2CHCl per g. The increase in chloride concentration after degradation was quantitative when compared with the decrease in organically bound chlorine. The degree of CCl2CHCl degradation was affected by Me2S2; this substance can significantly reduce the degrading ability of some tested cultures (> 60%); however, it does not cause this inhibition with others.

Acinetobacter↗