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Biomedical subjects

G Dieckmann

Publications and source records attributed to G Dieckmann.

At least 19 recordsLinked to original sources
PubMed1997

Primary Production in Antarctic Sea Ice

A numerical model shows that in Antarctic sea ice, increased flooding in regions with thick snow cover enhances primary production in the infiltration (surface) layer. Productivity in the freeboard (sea level) layer is also determined by sea ice porosity, which varies with temperature. Spatial and temporal variation in snow thickness and the proportion of first-year ice thus determine regional differences in sea ice primary production. Model results show that of the 40 teragrams of carbon produced annually in the Antarctic ice pack, 75 percent was associated with first-year ice and nearly 50 percent was produced in the Weddell Sea.

Journal Article↗
PubMed1991

Stereotactic removal of foreign bodies in the maxillofacial area.

A technique is described for making it possible to localize any deep-seated radiopaque foreign body in the soft tissues and skeleton of the maxillofacial area. Using a stereotactic guide system, any point in the facial skeleton can be reached exactly, with precalculated precision, from any point outside the face. Thus, a foreign body can be exposed and subsequently removed by a surgical approach that gives minimal discomfort and carries low risk. The target probe serves the surgeon as a guide bar whilst the tissue is dissected. A precondition of successful stereotactic operations in the head and neck area is close cooperation between neurosurgeons and maxillofacial surgeons.

Aged↗
PubMed1989

[Microsurgical resection of small brain tumor processes with stereotactic control].

From 1986 we have operated upon 13 patients with small neoplasms localised deep intracerebrally or subcortically in the central region with stereotactic guidance. Exact localisation of the tumour was one aim, whereas another one was to avoid damaging functionally important structures. In the first two patients we performed stereotactic marking of the tumour after craniotomy. The following procedure was found to be particularly useful: - determination of the tumour coordinates and planning of the approach - approach by means of a stereotactically guided probe, if necessary biopsy - stereotactically guided introduction of the leading catheter - removal of the stereotactic frame and bedding of the patient - craniotomy and microsurgical resection of the tumour This surgical procedure may be performed in one or two separate sessions. The accuracy of microsurgical tumour resection achieved by stereotactic means resulted in a remarkable reduction of postoperative neurological deficits.

Adult↗
PubMed1988

Psychiatric and neuropsychological findings after stereotactic hypothalamotomy, in cases of extreme sexual aggressivity.

Report on 14 cases treated for aggressive sexual delinquency by unilateral ventromedial hypothalamotomy. Eight of them had a thorough psychiatric and psychological examination during follow-up. The following constant modifications were found: Decrease in the domination by sexual drive, increase in the fluency in semantic contexts, increase of rapidity of visual image formation and of coordinative perception processes, positive modifications in the scope of some personality dimensions (poise, openness, self-criticism), decreased colour perception, increased appetite. The structure of the patient's sexuality was not changed but the probability of a specific aggressive behaviour reduced, due to the diminished sexual drive thus allowing a positive consolidation of their social interactions with more harmonic relationships to the families or partners. These results give proof that the many prejudices and aversions against this type of therapy are not justified.

Aggression↗
PubMed1988

[An applicator for the implantation of I125 seeds for interstitial therapy of brain tumors].

A compact magazine has been developed allowing a quick and easy implantation of I-125 seeds in interstitial therapy of intracranial tumors. The magazine is made of steel and has the shape of a right parallelepiped. One seed can be put each time into a movable insert. The magazine is connected to a normal application canula. It is easy to handle and contributes much to radioprotection.

Brachytherapy↗
PubMed1987

Retrogasserian glycerol injection or percutaneous stimulation in the treatment of typical and atypical trigeminal pain.

Of 164 patients with trigeminal neuralgia treated by percutaneous retrogasserian glycerol injections, we have studied the long-term outcome (one to four years) of 72 patients. 51 patients suffered from idiopathic trigeminal neuralgia, and of these 92% were freed from pain by the operation. 21 patients suffered from symptomatic trigeminal neuralgia due to multiple sclerosis or of traumatic or infectious origin. Of these, only 38% became free of pain. A further 8 patients with facial deafferentation pain who underwent treatment by retrogasserian neurostimulation with a permanently implanted electrode were included in this study. 4 of these patients were rendered free of pain by this procedure.

Denervation↗
PubMed1987

Five-and-a-half years' experience with percutaneous retrogasserian glycerol rhizotomy in treatment of trigeminal neuralgia.

The results of treating trigeminal neuralgia with percutaneous retroganglionic glycerol rhizotomy in 319 patients from an overall series of 394 patients with 459 operations carried out over a period of 5 1/2 years are reported. Idiopathic trigeminal neuralgia was the diagnosis in 252 patients. 34 patients had trigeminal neuralgia associated with multiple sclerosis. The remaining 33 patients suffered from symptomatic trigeminal neuralgia or atypical facial pain. 230 patients (91.3%) with idiopathic trigeminal neuralgia and 30 patients (88.2%) with multiple sclerosis reported complete freedom from pain. In 12 patients (4.8%) of those with tic douloureux and in 1 patient (2.9%) with multiple sclerosis, pain was alleviated, and the patients required a reduced pharmacotherapy. 10 patients (3.9%) and 3 patients (8.8%) were considered to be treatment failures. The rate of recurrences within the first 2 years was 10.9 and 40.0%, respectively. In the long-term, the rate of recurrences in patients with tic douloureux was 36.9%. 144 patients (45.1%) noticed a hypesthesia. 132 patients (41.4%) had hypalgesia following the procedure, and there was a decrease of symptoms in the long-term observation in 20.0% of the patients. 59 patients (18.5%) developed dysesthesia postoperatively which regressed only to an inappreciable extent in the long-term course. In 16 patients (5.0%) exclusively with a preexisting organic lesion or who had received surgical pretreatment, there was a loss of corneal sensation. The investigation showed on the one hand the effectiveness of the method, but on the other hand also the possibility of marked sensory disorder in selected cases.

Administration, Cutaneous↗
PubMed1985

Bipolar spinal cord stimulation for spasmodic torticollis.

Four years' experience with electrical stimulation of the cervical cord is reported for 18 patients suffering from spasmodic torticollis. Permanent 1,100-Hz stimulation of the C2-C4 level resulted in a marked improvement in 50% of the patients, in a satisfactory result in 27.8% and in an unsatisfactory result in 22.2%. Muscular tension and related pain were reduced within 8 days to 4 months postoperatively. A measurable improvement of head posture rendered objective by a mechanoelectrical measuring device could only be observed after a continuous stimulation over 8-12 months. The procedure is nondestructive and reversible, complications consisted only in those related to the stimulation system itself.

Adult↗
PubMed1984

[Digital roentgen video image processing for target calculation in stereotactic neurosurgery].

The basic methods for calculating targets in stereotactic cerebral operations, using radiography or CT sections for special operations, can now be extended by a new method, depending on image generating system from a digital x-ray video chain. A micro-computer was used in order to calculate image measurements, angulation of the apparatus and documentation of the surgical procedures.

Brain↗
PubMed1983

Digital radiography for target point evaluation in stereotactic neurosurgery.

Today, the usual target point evaluation during stereotactic operations using planar X-ray films can be supplemented by digital video storage. The picture-delivering system is a digital X-ray video chain which replaces the X-ray film. Evaluation of target point coordinates as well as parameters of electrode approach and positioning are determined by a microcomputer. Such an inexpensive system is described.

Brain Diseases↗
PubMed1981

[Local pseudocancerous inflammatory polyposis in Crohn's disease of the colon. Usefulness of coloscopy (author's transl)].

In Crohn's granulomatous colitis large pseudopolyps may produce local lesions with radiological images resembling cancer. In the case reported here, three successive lesions of similar radiological appearance located on different sites were found on post-operative examination to be proliferative pseudopolyps adjacent to typical granulomas. In all previously published cases, even when the patient was known to have Crohn's disease colectomy was invariably performed, probably for fear of a malignant tumour. Coloscopy, and particularly biopsies showing non-malignant lesions, could result in conservative treatment. Granulomas are more exceptionally found.

Colonoscopy↗
PubMed1981

Electromyographic activity of neck muscles in patients affected by retrocollis under the influence of stimulation and coagulation of the prestitial nucleus of the midbrain.

In 2 patients with retrocollis, the positive effects obtained by stereotactic high frequency coagulation of the prestitial nucleus on the tonic activity of the neck muscle were studied electromyographically and clinically. Before the stereotactic therapy, electromyographic recordings at rest were recorded from the musculi splenii. During stimulation of the prestitial nucleus at frequencies of 8, 25 and 50 Hz, the EMG activity at rest diminished in frequency and amplitude and ultimately disappeared. Passage from the EMG recordings at rest to electrical silence took place, in one case, though a rhythmic activity of potentials grouped at 11/s. After coagulation of the prestitial nucleus, the involuntary contractions of neck muscles disappeared and electrical silence occurred. On reexamination 1 month later, the positive results were still present.

Electric Stimulation↗