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Biomedical subjects

L Günther

Publications and source records attributed to L Günther.

17 recordsLinked to original sources
PubMed2006

Two times unlucky: treatment of repeated adjacent vertebral fractures following posterolateral interbody fusion.

Posterolateral interbody fusion with cages and posterior fixation is a widespread, accepted method in the treatment of lumbar instability with and without spinal stenosis. Adjacent level instability was occasionally detected in the neighbouring discs. A fracture of the adjacent vertebral body including the upper disc was not reported in the literature. The authors describe a case of a female patient with two time fractures in the adjacent levels-nontraumatic and traumatic-after posterolateral fusion. Recommendations regarding the operative treatment were given.

Aged↗
PubMed2005

Microstructure formation in dip-coated particulate films.

The microstructure-dependence of dip-coated particulate thin films on the stability of an aqueous silica sol used as coating bath is studied. Different stability conditions are adjusted in the sol by changing electrolyte concentration and pH value. Care was taken to avoid pronounced aggregation of the particles before the coating process. The characterization of the stability behavior gives clear evidence of a non-DLVO contribution at low pH values that is attributed to hydration forces. Structural evolution of the particulate network during film formation is studied using a dialysis accumulation procedure. The viscosity of the accumulated sol is measured as a function of shear rate and related to the drying characteristic of the coating process. Atomic force microscopy (AFM), small-angle X-ray scattering (SAXS) and N2 sorption are used to obtain information on the surface and volume structure of the dip-coated films. The structure of coatings is found to distinctly vary with stability parameters. This is attributed to changing interactions during the first drying stage. Finally, the influence of coating structures on the light transmission properties is determined. A comparison between the extinction of the uncoated and the coated substrate revealed a difference of up to +/-50% in dependence on the microstructure.

Journal Article↗
PubMed2005

[Experiences with surgical management of facial basal cell carcinoma and procedures for plastic reconstruction].

BACKGROUND: No recurrences and optimal aesthetic outcomes after R0 resection and plastic reconstruction of the face are the goals in the surgical treatment of basal cell carcinoma. The aim of this study was to evaluate recurrence rates and to evaluate different reconstructive techniques. PATIENTS AND METHODS: This study included 205 follow-up patients undergoing R0 resection of primary basal cell carcinoma and facial skin reconstruction between 1998 and 2002; data were analyzed retrospectively. RESULTS: The most frequent locations of basal cell carcinoma were the nasal (40.5%) and orbital (22.9%) regions. The rate of recurrence after 2.5 years (6 months-5 years) was 7.3%. Local flaps, full-thickness skin grafts, and sliding flaps were usually performed; indications for split-thickness skin grafts were rare. Disturbances of sensation were found in only 3.6% of the sliding flaps and in 11.7% of the local flaps, but 22.7% in full-thickness and 38.7% in split-thickness skin grafts. The aesthetic outcome, evaluated by clinical inspection and a patient satisfaction score, was classified as "unobtrusive" and "good or excellent" for 88.4% of local flaps, 92.6% of sliding flaps, but only for 66.4% of full-thickness and 54% of split-thickness skin grafts. CONCLUSION: Local flaps and sliding flaps result in better aesthetic and neurological outcomes after reconstruction of facial skin regions. Skin grafts have their indications as an alternative procedure in cases of critical indications for flaps.

Adult↗
PubMed2005

[Pierre Robin sequence: postoperative complications following cleft palate surgery. A retrospective study covering 25 years].

BACKGROUND: In a 25-year retrospective review of 1976-2000, the postoperative course after cleft palate surgery and pharyngeal flap surgery in 87 children with Pierre Robin sequence was studied. PATIENTS AND METHODS: The study comprised 114 interventions with 87 primary palatoplasties; 17 patients required palatal fistulae repair and 10 children were treated with secondary pharyngoplasty procedures. All children were divided into three postnatal risk groups according to the severity of their symptoms at birth and in the course of the early months of life. RESULTS: A direct correlation was seen between the incidence of early postnatal difficulties and the postoperative obstructive complications after cleft palate surgery and pharyngeal flap surgery. Thus, children experiencing obstructive problems at birth (high postnatal risk group) displayed more severe complications at the time after cleft palate repair. In children undergoing pharyngeal flap surgery not only early postoperative obstruction but also late obstructive sleep apnea can occur.

Abnormalities, Multiple↗
PubMed2005

Glucagon expression shift in a syngeneic single-donor intrahepatic rat islet transplantation model.

In the native rat pancreas glucagon is expressed by alpha cells in the outer layer of the spheroid islet, producing a circular immunohistochemical staining pattern. We asked whether this pattern would remain unchanged after short-term and long-term intrahepatic islet transplantation. Islets of inbred Lewis rats were isolated with liberase, purified by discontinuous density gradients, handpicked, and cultured for 24 hours. After rats were rendered diabetic with streptozotocin, islets were implanted intraportally. Transplanted animals were sacrificed at 1 to 2 days (n = 5) or 100 days (n = 6). Islet clusters were detected by hematoxylen-and-eosin staining. Serial slides were stained for glucagon and insulin with the alkaline phosphatase and alkaline phosphate method at 1 to 2 days after transplantation islets with strong insulin expression were found within the portal vein branches. However, glucagon staining showed an incomplete circular staining pattern. After 100 days insulin expression remained strong, whereas only few glucagon-expressing cells were detected. Intrapancreatic islets showed inversion of the ratio of insulin- to glucagon-positive cells in favor of the glucagon-expressing cells that now composed the major part of the islet. Streptozotocin had selectively damaged beta cells in the recipient. In transplanted islets glucagon expression faded over time, possibly due to a functional involution process or to stress/inflammatory mechanisms during the isolation, transplantation, and the posttransplantation periods.

Animals↗
PubMed2001

Heme oxygenase-1 protects pancreatic beta cells from apoptosis caused by various stimuli.

BACKGROUND: Several problems can occur after allogeneic islet transplantation: primary nonfunction, rejection, and the recurrence of autoimmune disease, which involve attack by the recipient's cytokines, T cells, natural killer cells, and monocytes on the donor's beta cells, which leads to beta-cell destruction. Recent studies have revealed that loss of transplanted islets is caused mainly by apoptosis. Heme oxygenase-1 (HO-1) is one of the antiapoptotic genes up-regulated under stress conditions. The aim of this work was to investigate any mechanisms of HO-1-mediated protection of beta cells from apoptosis. METHODS: Apoptosis was assessed by comparison of viable transfected cells with and without apoptotic stimuli, and with and without HO-1 overexpression. Activation and function of p38 mitogen-activated protein kinase were determined using the specific inhibitor SB203580. RESULTS: We have shown that HO-1 mediates antiapoptotic effects in beta cells. The percentage of apoptotic cells after stimulation with tumor necrosis factor a decreased from 75% without HO-1 to 5% when HO-1 was overexpressed. Our data indicate that HO-1 acts as a signal terminator of tumor necrosis factor alpha-induced apoptosis by modulation of the p38 mitogen-activated protein kinase pathway. CONCLUSIONS: Profound cell stress that occurs in islets after transplantation, as well as at the onset of diabetes, results in beta-cell loss through apoptosis. Protection of beta cells by HO-1 improves their survival in vitro after various proapoptotic stimuli, suggesting that HO-1 suppresses one or several signaling pathways leading to apoptosis. We hypothesize that our in vitro findings can be extrapolated to the in vivo situation, and we propose that expression of HO-1 in islets may illuminate a valuable new approach to improving diabetes treatment.

Animals↗
PubMed2000

[Associated anomalies in lip-maxillopalatal clefts].

BACKGROUND: Retrospective studies of cleft lip and palate patients suggest a multifactorial aetiology for this condition. Many patients exhibit multiple defects, often removed from the orofacial region. The frequency and location of such coexistent abnormalities vary between studies. PATIENTS: A retrospective case-note study of 1,737 individuals with orofacial cleft, treated between 1974 and 1998 at our centre, was undertaken to assess the frequency of associated malformations and syndromes. RESULTS: Associated malformations were found to be present in 33% of all cases investigated. In nearly one half of these individuals (48%), defects could be attributed to recognisable syndromes. Patients with isolated palatal clefts (45.6%) and those with bilateral clefts of the lip and palate (35.3%) were particularly well-represented. The following problems were observed relatively frequently: Cerebral anomalies (16%), facial anomalies (14%), heart malformations (15%), anomalies of the extremities (9%) and urogenital tract abnormalities (8%). In contrast, endocrine aberrations were identified sporadically (0.5%). A partial situs inversus was found only in one case. CONCLUSION: As clefts of the lip and palate are frequently associated with additional malformations, the importance of thorough interdisciplinary neonatal screening cannot be over emphasised.

Abnormalities, Multiple↗
PubMed2000

Technique and feasibility of a dual staining method for estrogen receptors and AgNORs.

A new staining method for dual demonstration of Estrogen receptors (ER) and argyrophilc Nucleolus-Organizer Regions (AgNORs) was developed. To rule out possible reciprocal effects, serial slides of 10 invasive ductale breast cancers were stained with either the single staining method or the simultaneous ER/AgNOR-staining method and investigated comparatively. By measuring the slides with the image analysis system AMBA, reciprocal effects could be excluded. It was proven that dual staining of both markers results in a reproducible and specific staining result. We concluded that it is justified to measure AgNORs in immunohistochemically stained cells.

Biomarkers, Tumor↗
PubMed2000

Different proliferation patterns in breast cancer: AgNOR measurements in ER-negative and ER-positive tumor cells.

The relation between estrogen receptors (ER) and argyrophilic nucleolar organizer regions (AgNORs) in situ within human breast cancer cells was analyzed. For AgNOR measurements in 49 invasive breast carcinomas, a new reproducible staining method for dual demonstration of ER and AgNORs was applied. Quantitative AgNOR variables were determined in ER-positive and ER-negative tumor cells by digital image analysis. The relationships between AgNOR parameters of ER-positive and ER-negative cells and other prognostic factors of breast cancer [Bloom-Richardson-Grading and growth fraction (Ki-67 index)] were investigated. A higher AgNOR content in ER-negative cells and a special clustering phenomenon in ER-positive tumor cells were found. Correlation with other criteria of malignant potential could be exclusively demonstrated for ER-negative cells. ER-negative cells of breast cancer can be characterized as the more malignant and possibly prognosis-dictating cell fraction. Thus, ER-negative cells probably contribute more to the progression of the tumor disease and furthermore to the prognosis than ER-positive cells. We recommend measurement AgNORs exclusively in ER-negative cells of breast cancer.

Adult↗
PubMed1997

[The sitting position in neurosurgical operations. Results of a survey].

METHODS: In February 1995 a questionnaire was sent out on perioperative management during neurosurgical operations performed in the sitting position to 136 centres and hospitals within the Federal Republic of Germany that perform neuroanaesthesia. The response rate was 61.02%. Besides the question of perioperative monitoring during neurosurgical operations in the sitting position, we asked about currently used positions for patients during the following neurosurgical operations:posterior fossa, craniospinal and posterior cervical surgery. RESULTS: Of all centres, 32.9% use the sitting position only for posterior fossa and craniospinal surgery. For posterior cervical surgery the sitting and prone positions are favoured by 25.6% of all clinics. Nonspecific basic monitoring (electrocardiogram, pulse oximetry, central venous pressure, invasive or noninvasive arterial pressure) is an accepted standard in all clinics. Capnometry, as a specific monitor for venous air embolism, is used in all centres (100%). Precordial Doppler ultrasound (US) monitoring is used in 69.2% of all clinics; 3.8% use transoesophageal Doppler US as a diagnostic method for venous air embolism. DISCUSSION: The sitting position is the preferred position for posterior fossa and craniospinal surgery in neurosurgical patients in Germany. For posterior cervical surgery the German centres use both the sitting and prone positions. Alternative positions like the lateral or the "park-bench" positions are hardly ever used. The essential monitoring devices for neurosurgical operations in the sitting position, as recommended after the survey by the German Society for Anaesthesiology and Intensive Care Medicine (DGAI) in 1995, are predominantly used. However, the use of Doppler US (precordial or transoesophageal) for the detection of venous air embolism and the preoperative diagnosis of a persistent foramen ovale is not yet widespread. CONCLUSIONS: To determine the effect of the recommendations by the DGAI on clinical practice, the survey will be repeated in 1997.

Anesthesia↗
PubMed1995

[3-dimensional computerized tomography in diagnosis and surgical planning of intracranial aneurysms].

Established alternative methods of visualisation of intracranial vessels--MR-angiography and angio-CT--give only two dimensional views similar to angiography. It is a subjective matter of the neurosurgeon's imagination to produce three dimensional views on the basis of these methods. Three dimensional processing of dynamic sequence or helical axial computed tomograms give any number you like of stereo-scopic views of the Willisi circulus. Comparing the usefulness of DSA and 3D-CT in 34 aneurysms, the latter often gives supplementary information concerning the direction, neck and adjacent arteries, helpful in planning surgery treatment. It is difficult or sometimes impossible to separate basal aneurysms (a.c.i.) from sinus cavernosus and skull base by this method, but especially in aneurysms located in the area of a.com.a. and c.m.a. the 3D-CT is sufficient for diagnosis and planning surgical treatment without DSA.

Angiography, Digital Subtraction↗
PubMed1995

[Severe pulmonary complications following venous air embolism in neurosurgical operations in sitting position--2 case reports].

The occurrence of air embolism during neurosurgical operations in sitting position is described in two cases. Besides the Doppler ultrasound evidence, relevant effects on the cardiopulmonary situation during surgery were observed, which in one case forced an early end of the operation. Postoperative management in both cases was complicated by a pulmonary oedema. In severe intraoperative cardiopulmonary complications in connection with venous air embolism, the existence of pulmonary oedema should be assumed. Confirmation of the diagnosis and the correct therapy depend upon frequent postoperative chest X-rays.

Brain Neoplasms↗
PubMed1994

[A new set for percutaneous implantation of the cardiac catheter in ventriculo-atrial shunt systems. A new technical note].

The percutaneous insertion of the atrial catheter for ventriculoatrial shunts reveals as a sufficient alternative method for the open surgical preparation of neck veins. The authors use a special set based on the Seldinger-Technique. The direct punction procedure of the internal jugular vein is a wellknown method in anaesthesia and intensive-care-medicine. First experiences show as well as a shorter operation times and better cosmetic results in the neck region.

Adult↗
PubMed1982

The glia types inthe visual system of adult rats, their shape variability, distribution patterns, and their lightoptically visible contacts to other tissue structures.

In silver impregnated coronal sections of adult rat brains the glia types of the Corpus geniculatum laterale, pars dorsalis (CGLd) an in area 17 were registered considering their form variants (FV), their intraareal distribution and their light optically demonstrable connexions to other tissue structures. Compared with the shape-determining light optically visible processes and perikarya, astrocytes show the lowest, microglial cells the greatest from variability. Transitional forms between the three glia types were not detected, but between elongated astrocytes and fiber astrocytes. An accumulation of elongated astrocytes, fiber astrocytes, and oligodendrocytes was found in the lateral zone of the CGLd, of protoplasmic astrocytes in the lateral and intermediary zones and at the rostral and caudal poles of the griseum, too. In the cortex distribution differences in the single laminae became also evident. Astrocytes were most concentrated in L I, oligodendrocytes and microglia, however, in L V. A few FV of the microglia were found to show a predominant localisation in specific laminae. Neither the total glia number nor the single glia types correlate with the neuron packing density. The frequency distribution of the FV of oligodendroglia in the CGLd and the visual cortex is similar, that of microglia, however, significantly deviating. Compared with the CGLd the oligodendrocytes of area 17 have smaller somata. Astrocytes, oligodendrocytes and microglial cells reveal structural contacts to different parts of the neurons, to blood vessels and other glial cells, too. Contacts between oligodendrocytes and microglial cells as well as astrocytes in satellite position could never be observed. In the cortex a few FV of microglia show typical connexions.

Animals↗