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R Hennig

Publications and source records attributed to R Hennig.

At least 19 recordsLinked to original sources
PubMed2004

On the role of the islets of Langerhans in pancreatic cancer.

Pancreatic cancer is a devastating disease characterized by a dismal prognosis with most patients dying within six months after diagnosis. Surgery is an option in less than one in five of these patients, and even with tumor resection the majority of patients succumb to the disease. Other effective treatment options are not available. Common features of pancreatic cancer are severe cachexia, marked insulin resistance and diabetes mellitus. Several studies have demonstrated connections between pancreatic cancers and the endocrine pancreas and this has raised questions regarding the role of the islets of Langerhans in pancreatic adenocarcinoma. This manuscript reviews the recent literature in this field and addresses several questions regarding the interaction between the islets of Langerhans and pancreatic cancer. This review considers the histological findings in pancreatic cancer, cell culture and animal experiments, the four islet cell types and the hormones they secrete, as well as the influence of the arachidonic acid pathways on islet cell function and pancreatic cancer. While pancreatic adenocarcinomas are ductal in nature, the cell of origin has not been identified and there is even some evidence that the islets may harbor the precursor cell. Considerable evidence suggests that the diabetes is caused by the tumor, while other studies have identified diabetes as a risk factor. Clearly, the islets are important in many aspects of this disease. However, even though progress has been made, some questions regarding the interaction of pancreatic cancer and the endocrine pancreas remain unanswered.

Adenocarcinoma↗
PubMed2003

Long-term expression of fibrogenic cytokines in radiation-induced damage to the internal anal sphincter.

BACKGROUND: There is accumulating evidence, both quantitative and qualitative, that pelvic irradiation affects anorectal function. However, the molecular mechanisms responsible for radiation-induced damage to the anal sphincter remain unclear. AIM: To determine the expression of transforming growth factor-beta 1 (TGF-beta 1) and its downstream effector connective tissue growth factor (CTGF) in the anal sphincter of a patient irradiated for prostate cancer. PATIENT: A 82 year-old patient developed a rectal adenocarcinoma and underwent an abdomino-perineal resection (APR), four years after receiving pelvic irradiation for prostate carcinoma. METHODS: Tissue sections of the anal sphincter were processed for histology. Immunostaining for TGF-beta 1 and CTGF were performed. RESULTS: CTGF and TGF-beta 1 immunoreactivity was detected in the irradiated anal sphincter, and was absent in controls. Immunoreactivity for both cytokines predominated in the internal sphincter. CTGF and TGF-beta 1 were preferentially detected in endothelial cells, myofibroblasts and fibroblasts; in addition, there was strong immunoreactivity for TGF-beta 1, but not for CTGF in smooth muscle cells of the anal canal. CONCLUSION: Four years after pelvic irradiation, radiation-induced damage appeared to affect predominantly the smooth muscle layer of the anal canal. The molecular mechanisms responsible for radiation-induced fibrosis to these tissues involve prolonged activation of TGF-beta 1 and its downstream effector CTGF.

Adenocarcinoma↗
PubMed2003

Does imprint cytology of brain tumours improve intraoperative diagnoses?

OBJECTIVES: To evaluate the diagnostic accuracy using frozen sections only and a combination of imprint cytology and frozen sections. MATERIAL AND METHODS: After introduction of imprint cytology as a supplement to frozen sections in 1999, 153 patients with brain tumours underwent stereotactic or open surgery. An equal number of cases prior to 1999 were chosen for comparison. Intraoperative diagnoses were compared with final diagnoses based on paraffin sections of the same tissue samples. The number of delayed intraoperative diagnoses was noted in each patient group. RESULTS: The combined use of the two techniques improved intraoperative diagnostic accuracy from 87 to 91% while the delayed intraoperative diagnoses were significantly reduced from 30 to 8. The choice of surgical procedure did not affect the outcome of the pathological investigations. CONCLUSION: A combination of frozen sections and imprints significantly reduced the number of delayed intraoperative diagnoses. Intraoperative diagnostic accuracy was improved, although not to a statistically significant level. Choice of surgical procedure did not affect the diagnostic outcome.

Adolescent↗
PubMed2002

Regional bone loss after orthotopic liver transplantation in inbred rats: the role of hepatic denervation.

Bone loss and long-term persistence of osteoporosis with increased fracture risk are common after liver transplantation. It is unknown whether transplantation-induced disruption of hepatic nerves, serving numerous regulatory metabolic and sensory functions, is herein involved. To test this possibility, we measured bone mineral density (BMD) by peripheral quantitative computed tomography (pQCT) and studied dynamic histomorphometry, radiocalcium kinetics, and biochemical parameters in 7 liver-transplanted and 7 sham-operated inbred rats. Although liver function was normal in TX rats, trabecular BMD of the first lumbar vertebra and total BMD of the femoral diaphysis were decreased by 13% and 6%, respectively, 9 months postsurgery. The breaking force of the femur was significantly lower by 21%. However, bone mass in the femoral and tibial metaphysis was preserved as evidenced by pQCT measurements and histomorphometry. Trabecular width and wall thickness were significantly decreased in vertebral cancellous bone, whereas indices of bone formation and resorption were normal or slightly reduced. Serum minerals, mineral balance, fractional and net absorption of Ca and Mg, serum calciotropic hormones, IGF-I, leptin, specific activity of 45Ca in bone, 45Ca excretion, and biochemical indices of bone formation and bone resorption remained unchanged. We conclude that liver transplantation-related denervation causes cancellous and cortical bone loss in well-innervated bone sites such as the lumbar spine and the long bone diaphysis. Cancellous bone loss in TX rats is due to an impairment of osteoblast team performance and subsequent trabecular thinning. The mechanism uncovered by our study may contribute to long-term bone loss after liver transplantation.

Animals↗
PubMed2000

A new procedure for frameless computer navigated stereotaxy.

OBJECTIVE: Stereotactic procedures using frame-based systems have become well established in neurosurgery. Later, stereotactic computers have provided the neurosurgeon with a broader range of applications. A new, frameless stereotactic guide which utilizes the navigational abilities of a computer has been developed. This clinical study evaluates the accuracy and safety of the system when applied for puncture of tumours and abscesses in the cerebrum. METHODS: Using a frameless setup 36 patients were operated on for a total of 39 intracranial processes over a period of two years. Three patients were operated on twice. Computer data, time of surgery, anesthesia, complications, tumour localization and tissue examinations were recorded. RESULTS: Biopsies were obtained from all lobes of the cerebrum and a diagnosis established in all cases except two. Mean age and total range was 52 years and 15-82 years, respectively. Median time of surgery was approximately 60 minutes including positioning of the patient and the registration process on the stereotactic computer. Local anesthesia was used for 25 operations and general anesthesia for 14 operations. There was one postoperative abscess formation in a previously immunosuppressed patient and a per-operative epileptic seizure caused by electrocoagulation of the dura in a second patient. CONCLUSIONS: Based on this clinical study a new procedure for obtaining stereotactic biopsies of intracranial processes is introduced. All tumours were successfully reached with two cases of complications.

Adolescent↗
PubMed2000

Mechanical accuracy of a new stereotactic guide.

OBJECTIVE: A new stereotactic guide using a navigational computer is developed for stereotactic procedures. In order to compare the mechanical accuracy of the guide to frame based systems, an error analysis study was designed. METHODS: A biopsy procedure was simulated using a phantom model. Targets with known co-ordinates in a three-dimensional Cartesian co-ordinate system were positioned inside the skull model. A biopsy needle was inserted along computer set trajectories from three different entry points. The position of the biopsy needle in the co-ordinate system was measured. Distance from needle tip to target was calculated and defined as the error of the system for each trial. The results were statistically analyzed for precision and biasedness. RESULTS: A total of 242 accuracy measurements (182 on two MRI scans, 60 on one CT scan) were carried out. Mean incision length along the trajectories was 59 mm. Mean error using MRI scans was 3.8 mm and for the CT scan 2.9 mm. The error of the stereotactic computer was found to be 1.0 mm with both MR and CT imaging. The main cause of error for the MRI based trials was distortion of the magnetic field. CONCLUSION: The results indicate a stereotactic system with high degree of accuracy. This is confirmed by a clinical study of 39 biopsies where all tumours were reached. MRI affected the mechanical accuracy significantly due to distortion of the magnetic field. The accuracy is comparable to other studies performed on both stereotactic computers and frame based systems.

Biopsy, Needle↗
PubMed1999

[Primary lymphoma of the central nervous system].

Primary lymphoma of the central nervous system is an important diagnosis to consider in any patient with an expansive lesion of unknown origin. The incidence of this cancer is reported to be increasing. We collected retrospective data from the files on all patients with brain tumours treated surgically at the University Hospital of Tromsø in the 1986-98 period (n = 513). Of 283 patients operated for brain tumours from 1986 to 1994, only one (0.4%) had a primary lymphoma. Of 230 patients treated from 1995 to 1998 seven (3%) suffered from the same condition. Two of the eight patients had T-cell lymphomas. Primary lymphoma of the central nervous system is a highly invasive tumour and should preferably be treated with chemotherapy and irradiation. The use of surgery is controversial. In most cases, surgery should be restricted to biopsy only.

Aged↗
PubMed1999

Intracavity fractionated balloon brachytherapy in glioblastoma.

In order to reduce hospitalisation time for patients receiving postoperative radiotherapy a phase I-II study of intracavity balloon brachytherapy was instituted. An indwelling balloon catheter was implanted during the closing phase of the initial operation. Starting on the second or third postoperative day the catheter was afterloaded with a high dose rate isotope via a remotely controlled afterloading system. The treatment consisted of 10-12 fractions over a period of 5-6 days, with each treatment session requiring approximately 15 minutes. No external beam radiation was given. Forty-four newly diagnosed patients were treated. A total dose of either 60 Gy (33 patients) or 72 Gy (11 patients) was given. The overall median survival was 11.7 months, (range 2.7-50.9). The treatment was well tolerated and none of the applicators were removed prematurely. The total median hospital stay for this group of patients was significantly reduced compared to more conventional protocols. This study indicates that intracavity high dose rate balloon brachytherapy can achieve survival rates equivalent to those of conventional radiotherapy and is both cost and time efficient.

Adult↗
PubMed1999

Burr hole evacuation of chronic subdural haematomas followed by continuous inflow and outflow irrigation.

Chronic subdural haematomas are prone to recollect, increasing the risk of further complications and death. Burr hole evacuation followed by continuous irrigation of a Ringer solution into the remaining subdural cavity, allows remaining blood to be washed out and the brain to re-expand. This technique was compared with burr hole evacuation either without or with a passive drainage and craniotomy, respectively. Reformation of haematomas after continuous irrigation occurred in 2.6% (2/77); more than a twelve (32.6%; 15/46) and a nine (23.8%; 5/21) times rate reduction compared to burr hole evacuation without and with passive drainage, respectively. Compared to the craniotomy results, the rate dropped seventeen times (44.4%; 4/9). Expect from the two rebleedings in 77 haematomas operated on through burr holes followed by irrigation, all patients recovered including nine recurrent haematomas re-operated on by this method. Recurrent haematomas operated on through burr hole evacuation alone or with insertion of a passive drainage, recollected in 50% (2/4) and 33.3% (2/6). Similar rate after craniotomies was 11.1% (1/9). Neither infections nor deaths followed burr hole evacuation combined with continuous irrigation, whereas 5.3% (2/38) and 5.9% (1/17) suffered from empyema after burr hole evacuation alone or combined with a passive drainage, respectively. Five (9.1%) of these 55 patients died either from empyemas (three) or rebleedings (two). Recurrent haematomas evacuated through a craniotomy had no complications from infections. Compared to other methods, continuous irrigation reduces the need for re-operation significantly by preventing haematoma recurrence and empyema formation. Contrary to other surgical techniques, haematoma recurrence after second time surgery did not occur.

Adult↗
PubMed1998

[Vaccination status and implementation of recommendations for vaccination with special reference to measles-mumps-rubella vaccination. 1995 program for school entrance].

Children who took part in the medical examination for elementary school starters and who could present a certificate of vaccination were given a written vaccination recommendation. On the first day of school the recommendation sheets filled out by the family doctor or a paediatrician were collected and analysed anonymously. 2194 of 2965 children received a vaccination recommendation. 1047 sheets could be interpreted. Based on the current recommendation of the STIKO (German official vaccination council) a MMR (measles, mumps, rubella) vaccination was suggested in 1001 cases. Only 53.1% of the proposed vaccinations have been given, despite consultation with the family doctor or paediatrician.

Child↗
PubMed1996

[Leakage of cerebrospinal fluid. Diagnosis and treatment].

Leakage of cerebrospinal fluid may occur after fracture of the skull base or after surgery on the skull base, nose, or paranasal sinuses. Further causes of cerebrospinal fluid leakage are tumours and malformations. It may also occur spontaneously. We describe four case reports illustrating diagnostic and surgical problems. Cerebrospinal fluid oto- and rhinorrhoea should be suspected in cases of recurring purulent meningitis. Immunologic demonstration of beta(2)-transferrin in secretions from the nose and ear is a diagnostic sign of cerebrospinal fluid or perilymph. Digital subtraction cisternography, CT cisternography, and flow-sensitive magnetic resonance imaging are sensitive methods for localising dural leakage. Frontal craniotomy has been the traditional surgical approach. The recent involvement of transnasal endoscopic sinus surgery and microsurgery has made it possible to treat cerebrospinal fluid oto- and rhinorrhoea with a high degree of success and less operative morbidity.

Adolescent↗
PubMed1996

Phasic action of the tensor muscle modulates the calling song in cicadas

The effect of tensor muscle contraction on sound production by the tymbal was investigated in three species of cicadas (Tettigetta josei, Tettigetta argentata and Tympanistalna gastrica). All species showed a strict time correlation between the activity of the tymbal motoneurone and the discharge of motor units in the tensor nerve during the calling song. Lesion of the tensor nerve abolished the amplitude modulation of the calling song, but this modulation was restored by electrical stimulation of the tensor nerve or by mechanically pushing the tensor sclerite. Electrical stimulation of the tensor nerve at frequencies higher than 30­40 Hz changed the sound amplitude. In Tett. josei and Tett. argentata there was a gradual increase in sound amplitude with increasing frequency of tensor nerve stimulation, while in Tymp. gastrica there was a sudden reduction in sound amplitude at stimulation frequencies higher than 30 Hz. This contrasting effect in Tymp. gastrica was due to a bistable tymbal frame. Changes in sound pulse amplitude were positively correlated with changes in the time lag measured from tymbal motoneurone stimulation to the sound pulse. The tensor muscle acted phasically because electrical stimulation of the tensor nerve during a time window (0­10 ms) before electrical stimulation of the tymbal motoneurone was most effective in eliciting amplitude modulations. In all species, the tensor muscle action visibly changed the shape of the tymbal. Despite the opposite effects of the tensor muscle on sound pulse amplitude observed between Tettigetta and Tympanistalna species, the tensor muscle of both acts by modulating the shape of the tymbal, which changes the force required for the tymbal muscle to buckle the tymbal.

Journal Article↗
PubMed1994

Transient reinnervation of antagonistic muscles by the same motoneuron.

When reinnervation is allowed after a sciatic nerve cut in the adult rat, motoneuron axons may branch to innervate antagonistic muscles. This multiple innervation is widespread, but transient. Fourteen weeks after denervation isometric muscle contraction experiments and studies with anterograde transport of the fluorescent tracer Fast Blue showed that branches from the same motoneurons reached the distal part of the tibial nerve and either the soleus or the extensor digitorum longus muscles or both muscles. Retrogradely double-labeled motoneurons were found after injections of different fluorescent tracers into these muscles. Sixty-four to 88 weeks after the nerve cut, similar experiments showed that selective innervation was reestablished. The findings suggest a selective mechanism for axon withdrawal in an adult mammal.

Amidines↗
PubMed1994

FUNCTION OF THE TENSOR MUSCLE IN THE CICADA TIBICEN LINNEI

The calling song and the disturbance squawk of the cicada Tibicen linnei (Insecta: Homoptera) are described in terms of their physical parameters. The calling song is composed of quiet parts, which are very similar to the disturbance squawk, and loud parts, which are amplitude- and rate-modulated. The role of the tensor muscle acting on the tymbal frame in modulating the sound pulse amplitude was investigated. We demonstrate by tensor nerve recordings, by mechanical mimicking of the tensor muscle action and by electrical stimulation of the tensor nerve, that the contraction of the tensor muscle is responsible for (a) initiating sound production and (b) modulating the sound pulse amplitude. These results allow us to construct a model which suggests that the tensor shifts the tymbal into a mechanical working range that enables sound production and modulation of the sound pulse amplitude.

Journal Article↗
PubMed1994

AUDITORY THRESHOLD CHANGE IN SINGING CICADAS

The hearing sensitivity in singing cicadas is reduced during sound production by a folding of the tympanal membranes. Using electrophysiological recording and nerve stimulation techniques, we have shown an effect of the folded tympanum on the auditory threshold of two species of cicadas, Tibicen linnei and Okanagana rimosa. Auditory thresholds of both species increased by about 20 dB when the tympana folded during singing. In T. linnei the increase in threshold affected the whole frequency range, from 1 to 16 kHz, in a similar way. Electrical stimulation of one or both auditory nerves resulted in a folding of both tympanal membranes in a way very similar to that seen in singing animals. We have demonstrated that a cicada male is able to adjust its auditory threshold within a range of about 20 dB by the tympanal folding mechanism.

Journal Article↗