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Biomedical subjects

R Firsching

Publications and source records attributed to R Firsching.

At least 55 records · Page 3Linked to original sources
PubMed1995

Central retinal venous outflow pressure.

BACKGROUND: Does the venous collapse phenomenon provide the possibility of venous dynamometry? METHOD: A technical model is presented which allows analysis of the conditions of the collapse of the central retinal vein in vitro. The conditions of the venous collapse were analysed with regard to intraocular pressure, intravasal pressure in the outflow of the central retinal vein and the overall perfusion. For clinical measurements dynamometry of the venous collapse is performed parallel to the experimental setting. RESULTS: The experiment reveals identical results for venous outflow pressure measured by venous dynamometry and by intravasal pressure detector. Venous dynamometry in vivo means that we use the onset of the venous collapse phenomenon to register the pressure in the central retinal vein at the point where it leaves the eye. Using this technique, retroocular obstruction of the venous outflow may be assessed. The venous outflow pressure itself depends on the venous flow resistance, intracranial pressure and arterial perfusion pressure. Any disorder of these three parameters may be assessed when the absolute venous outflow pressure is registered. CONCLUSION: The venous collapse phenomenon enables us to determine the venous outflow pressure. Clinical applications have proven promising.

Aged↗
PubMed1995

Gagel's granuloma (localized Langerhans cell histiocytosis) in the pituitary stalk.

A 46-year-old man with diabetes insipidus, hypothyroidism and hypocortisolism was found to have a tumor of the pituitary stalk. After transsphenoidal resection of the tumor substitution of cortisol and thyroxin was necessary. Pathological examination of the lesion revealed an extremely rare granulomatous infiltration classified as Gagel's granuloma (Langerhans' cell histiocytosis). Pre- and postoperative magnetic resonance imaging (MRI) studies, differential diagnosis and treatment of such lesions are presented.

Diabetes Insipidus↗
PubMed1995

[Dysphagia: a neurosurgical indication for an operation?].

Ventral osteophytes of the cervical spine can be the reason for dysphagia in rare cases. We present a 67-year old man with difficulties in swallowing for three years and a ventral osteophyte at the level of C 5/6. Native X-rays of the cervical spine, CT-scan and x-ray examination with barium meal and with a barium ball was performed. In our case the most useful procedure for operative indication was the dynamic examination with the barium ball which demonstrates clearly the obstructed oesophageal passage. During operation the ventral osteophyte was resected via ventral approach to the cervical spine. Postoperatively patient's symptoms completely disappeared. Differential diagnosis and therapy are discussed.

Aged↗
PubMed1994

Multimodal evoked potentials after subarachnoid haemorrhage.

In 59 comatose patients after subarachnoid haemorrhage somatosensory, visual, auditory and magnetic motor evoked potentials were registered. Evoked potentials proved to be of much less predictive value than in other causes of coma, such as head injury and others. While loss of cortical function was a safe predictor of a fatal outcome, preservation of evoked potentials has little prognostic relevance.

Adult↗
PubMed1994

Studies on the presence of magnesium in visceral amyloid.

The Magneson and Titan yellow tests were used to detect Mg in amyloid deposits in primary and secondary amyloidosis, in a pituitary tumour and in a case of equine cutaneous amyloidosis. Especially vascular amyloid deposits turned out to contain high levels of Mg. The significance of these findings remains unclear at present. Competition between Mg and Ca, the relationship between Mg in elastic fibres and amyloid P-component, and the high water content of amyloid along with the interaction of Mg with water are discussed.

Adenoma↗
PubMed1994

Long-term prognosis of low grade astrocytoma.

In 57 patients with astrocytoma grade I and in 65 patients with astrocytoma grade II, operated on between 1978 and 1988, diagnosis and follow up was based on computerized tomography (CT). The follow up period ranged from one to 13 years, mean follow up was 59 months for grade I and 41 months for grade II tumors. Histological differentiation between both grade I and grade II proved to have the highest prognostic value. The five year survival rate was 85% in grade I and 50% in grade II. Preoperative clinical findings were highly correlated with outcome. Age was found to be of low prognostic value. CT findings were not clearly related with survival. It is concluded that surgery should not be delayed, until more severe symptoms arise, since prognosis is better with lesser preoperative neurological deficits.

Adolescent↗
PubMed1993

The dynamics of magnetic resonance findings in patients with a spinal haematoma.

In 6 patients with an incomplete transverse section, magnetic resonance (MR) imaging revealed a spinal haematoma. The MR signal intensity changed with the interval between the haemorrhage and the MR investigation. Signal intensities of T1- and T2-weighted images exhibited specific changes with time after the haemorrhage, allowing for a retrospective assessment of the time of onset of the haemorrhage.

Adult↗
PubMed1993

Metals in tumors of the sellar region.

The contents of the metals Ca, Mg, Zn, Cu, Cr, and Mn in 7 different entities of tumors of the sellar region were evaluated by atomic absorption spectrophotometry. Increased values of Mg in coincidence with high Ca contents are explained by the competition of Mg to Ca and its potency to inhibit mineralization. Reports on the frequent coincidence of increased Zn levels with increased Ca levels were confirmed. The pattern of metal contents encountered in some tumors was rather related to the biological state of the tissue than to morphogenesis or descent from any specific embryonic layer. Regressive transformation like calcification or liquefaction had a distinct bearing on the distribution of metals.

Adenoma↗
PubMed1993

MRI follow-up in syringomyelia. Observations from twelve cases.

In 12 patients syringomyelia was diagnosed using MRI. The underlying cause was a hindbrain hernia in 8 patients, a posterior fossa cyst in one case, and in 3 patients the underlying cause remained unknown. Syringo-subarachnoid shunting in 8 patients failed to decrease pain and the size of the syrinx, motor lesion and gait disturbance in the majority of patients. A cysto-peritoneal shunt in the patient with a posterior fossa cyst and a syringo-peritoneal shunt resulted in a decreasing syrinx and clinical improvement.

Adult↗
PubMed1993

Relationship between magnesium and elastic fibres.

The presence of magnesium was demonstrated by histochemical methods in elastic fibres from different locations. After pretreatment with elastase a positive reaction could no longer be detected. Microfibrils which enclose the elastin core of the elastic fibres gave no positive reaction. These results support the supposition of a close relationship between Mg and elastin. Determination of the Ca/Mg ratio by atomic absorption spectrometry in variants of fibrous connective tissue showed a decreasing Ca level with increasing elasticity. The Ca/Mg ratio in lattices containing rubber-like particles disclosed striking diminution of Ca. These data support the speculation that the antagonism of Mg to Ca plays a fundamental role in the maintenance of elasticity. The special interaction of the Mg2+ ion with water molecules is very probably a further prerequisite for elasticity in natural elastic materials.

Calcium↗
PubMed1993

Interaction of magnesium and calcium in meningioma.

Ca and Mg contents were determined in 57 meningiomas. Techniques included atomic absorption spectrometry, topochemical detection and electron probe analysis. Elastic fibres demonstrated positive reaction with reagents for detection of Mg. One third of the tumours showed Mg levels higher than Ca levels. The findings gave rise to discussion on the importance of competition and antagonism between Ca and Mg for the formation of calcified structures. As the collagen producing propensity of meningiomas is mediated by interaction with Mg, we speculate that, in addition to the amount of Mg required for basic cell functions, increased Mg levels are needed, especially in the fibromatous variant.

Adult↗
PubMed1992

Rehabilitation after severe head injury.

123 survivors of severely head injured patients presenting with coma grade III show a decreasing mean duration of coma with increasing age. The numbers and frequency of good recovery decrease, whereas poor recovery increases with age. Increase of the duration of coma grade III produces an increase of the mean latency and time of recovery and of the frequency of poor recovery, regardless of the age of the patients. Increasing age does not increase the mean latency and time of recovery systematically. The important conclusion of this analysis is, that the clinical feature of coma grade III, corresponding to GCS score of 4 and RLS of 6 and 7, indicates a different kind of brain damage at various age groups. It represents a lesser degree of brain damage for younger patients under 20, than for those over 20. In our opinion our observations do not demonstrate a better capacity of recovery of the young patients: but the young patients show a more severe clinical picture than the older patients do, if only the clinical syndrome of coma grade III with extensor rigidity, is considered as a yardstick for comparison.

Activities of Daily Living↗
PubMed1992

Brain death: practicability of evoked potentials.

Multimodally evoked potentials were registered in 85 patients who fulfilled the criteria for brain death. While somatosensory and visual evoked potentials have been found to be of limited value for the diagnosis of brain death, the stepwise abolition of brain stem auditory evoked potentials (BAEP) confirmed brain death in 26 out of 85 patients, i.e. 31%. Registration of the abolition of BAEP is concluded to be a safe and acceptable confirmatory test. It is, however, more feasible for institutions, in which BAEP are analysed routinely. In spite of all efforts sequential BAEP could not be used for the diagnosis of brain death in the majority of cases either because of absence of reproducible responses at the initial registration or because the patient was already apnoic at the time of the initial BAEP. Assuming that bilateral preservation of wave I has the same significance as the stepwise abolition of BAEP, since it also proves the integrity of the peripheral receptor, BAEP are relevant for the declaration of brain death in approximately 30% of patients.

Brain Death↗
PubMed1992

Cerebral reperfusion in brain death of a newborn. Case report.

A case of "sudden infant death" after 15 minutes of successful resuscitation of cardiovascular function is presented. While apnoic cranial nerve areflexia and electrocerebral silence persisted, angiography and transcranial Doppler sonography demonstrated nearly normal cerebral perfusion, which even increased day by day inspite of the persistence of other signs of brain death. The phenomenon "cerebral reperfusion" is concluded to be compatible with the diagnosis of brain death.

Blood Flow Velocity↗
PubMed1992

Lesions of the sensorimotor region: somatosensory evoked potentials and ultrasound guided surgery.

In 10 patients with lesions of the sensorimotor cortex cortical SEP were registered to identify the postcentral gyrus, and intra-operative ultrasound sonography served to locate the lesion. The combination of both techniques helped to find the optimal approach to the lesion. Postoperative results were considered favourable, as only one patient suffered transient postoperative deterioration, six were unchanged and in three patients the pre-operative motor deficits were improved. The combination of intra-operative ultrasound and neurophysiological identification of the sensorimotor cortex is concluded as being useful in surgery within this region.

Adult↗
PubMed1992

Differentiation of oxytalan fibres from elastic fibres with reagents for detection of magnesium.

Elastic fibres in various human and animal tissues revealed positive results with reagents for the detection of magnesium. By contrast, no Mg could be detected in oxytalan fibres or in zonular fibres of the ciliary body, which are composed of microfibrils not containing elastin. Mg is therefore concluded to be associated with the elastin core of elastic fibres. Its antagonism to calcium is speculated to play a protective role in maintaining the extensibility of elastin.

Animals↗
PubMed1991

Cerebellar haemorrhage: management and prognosis.

Of 26 patients with CT confirmed intracerebellar haematoma, 17 had ventricular drainage performed and 7 patients had the haematoma evacuated. Eleven patients died. Mortality was clearly related to state of consciousness. Seven out of 8 non-comatose patients survived but 10 out of 18 comatose patients died. As there was no incidence of deterioration immediately following placement of a ventricular drainage, the actual risk of upward transtentorial herniation seemed low. Absence of evoked potentials in 6 patients accurately predicted a fatal outcome but normal SEP and BAEP were of lesser value for predicting survival.

Aged↗