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Biomedical subjects

T Stober

Publications and source records attributed to T Stober.

At least 19 recordsLinked to original sources
PubMed2001

Color stability of highly filled composite resin materials for facings.

OBJECTIVES: The aim of the investigation was to examine the color stability of seven resin-based facing composites with a high content of inorganic filling material (Colombus, Artglass, Sinfony, Targis, Zeta LC, Zeta HC, BelleGlass HP/dentine, BelleGlass HP/enamel). METHODS: Changes in color of test samples were determined after UV irradiation in a fast-action UV instrument, Sunset CPS+, and after storage in a mouthrinse, tea, coffee, red wine and a 0.1% turmeric (curcuma) solution. Color differences were measured by using a Castor colorimeter and the total amount of color difference represented as DeltaE. RESULTS: Red wine and the turmeric solution caused the most severe cases of discoloration (DeltaE>10). Tea, coffee, the mouthrinse and UV irradiation caused invisible (DeltaE<1) or visible (DeltaE>1), and to some extent clinically unacceptable (DeltaE>3.3), discoloration. SIGNIFICANCE: It is apparent from the results that it remains essential to improve the color stability of the composite resin materials used for facings.

Color↗
PubMed1989

Has plasma renin activity a prognostic significance in subarachnoid haemorrhage?

The possible relationship between plasma renin activity and neurological deficits was examined in ten patients with spontaneous subarachnoid haemorrhage in a prospective clinical study. The patients were examined daily, particular attention being given to signs of brain stem dysfunction. The degree of impaired consciousness was assessed using the Glasgow Coma Score. Plasma renin activity was determined on days 1-5, 7, 9, 11, 13, 15 and 21 after the initial bleeding episode using an Angiotensin-I-radioimmunoassay. Six of seven patients with signs of brain stem dysfunction displayed a marked increase in plasma renin activity. Thus a significant negative correlation between the degree of consciousness and the plasma renin activity resulted. An explanation for this correlation may be found in the localization of the autonomous centres and the high concentrations of renin in the hypothalamus and brain stem. The individual changes in plasma renin activity have prognostic significance, whereas single estimated plasma renin activities show great inter-individual differences and have only limited prognostic value.

Brain Diseases↗
PubMed1989

Elevated serum CK-BB levels in patients with cerebral transtentorial herniation after ischemic stroke.

We examined the time course of CK and its isoenzymes in 15 patients with severe ischemic stroke. Patients with cerebral transtentorial herniation (n = 7) had the highest CK-BB activity during herniation (1.54 +/- 0.6 U/L, mean +/- SD; range: 1.0-2.6 U/L). These values were distinctly above the values of a control group of 20 patients with non-neurological diseases (0.39 +/- 0.2 U/L, mean +/- SD). In patients with smaller lesions without herniation (n = 8) the maximum CK-BB increase was lower (0.56 +/- 0.26 U/L, mean +/- SD).

Aged↗
PubMed1989

[Isolated vitamin E deficiency].

Since the detection of vitamin E in 1922, nearly 50 years passed until the recognition that there is a pathogenic vitamin E deficiency in humans. Such a deficiency can be found mostly in a disturbed resorption or transport of the vitamin (mucoviscidosis, chronic cholestasis, abetalipoproteinaemia) and leads typically to a progredient spinocerebellar ataxia in combination with a polyneuropathy. Substitution of the vitamin may hinder a further progression or even lead to an amelioration of the symptoms. Prophylactic treatment in abetalipoproteinaemia prevents the otherwise unavoidable neurological deficits. Isolated vitamin E deficiency is a rare syndrome and the causes are still obscure. We observed a 26 year old male patient with such a isolated vitamin E deficiency who was hitherto thought to suffer from Friedreich's ataxia. The clinical feature showed in addition to the "classical" symptoms of vitamin E deficiency cranial nerve involvement, perioral dystonia and pyramidal signs. Histologically (M. gastrocnemius) we saw the described typical but not specific changes (neurogenic atrophy, phosphatase-positive vacuoles with myelin bodies, cores). An oral vitamin E resorption test yielded a very shortened serum half life. These results support the hypothesis that in the pathophysiology of isolated vitamin E deficiency malelimination plays an important role in addition the known malresorptions models.

Adult↗
PubMed1988

Changes in nocturnal sleep in Huntington's and Parkinson's disease.

There have been no reports of studies on nocturnal sleep or quantitative studies of sleep spindle density in Huntington's disease, whereas sleep in Parkinson's disease has been extensively reported. We therefore examined nocturnal sleep changes in patients with Parkinson's and Huntington's disease and compared them with a control group. The previously reported decrease in sleep spindle density was observed in patients with Parkinson's disease. The patients with Huntington's disease, however, had a significant increase in sleep spindle density, the nocturnal sleep pattern being normal in other respects when compared with the control group. This observation may provide a further diagnostic criterion in Huntington's disease.

Adult↗
PubMed1988

Cardiac arrhythmias in subarachnoid haemorrhage.

In this prospective study 52 patients with spontaneous subarachnoid haemorrhage were examined with respect to cardiac arrhythmias and their relationship to cerebral lesions. A continuous ECG was registered over an average of five days. Sinus tachycardia was the most frequently recorded arrhythmia, followed by multifocal ventricular extrasystoles, couplets, frequent supraventricular extrasystoles, non-sustained ventricular tachycardia, asystolia and sinus arrhythmia. A significant correlation was found between the clinical manifestation of a midbrain syndrome and sinus arrhythmia, and multifocal ventricular extrasystoles. This correlation points to the autonomic cardiovascular centres as the structures involved.

Adult↗
PubMed1988

Correlation of cardiac arrhythmias with brainstem compression in patients with intracerebral hemorrhage.

Neurogenically caused cardiac arrhythmias and their correlation to lesions within the central nervous system were examined prospectively in 54 patients with spontaneous intracerebral hemorrhage. All patients were examined neurologically daily for 3 weeks, with special attention given to signs of brainstem compression resulting from transtentorial herniation. Electrocardiograms were continuously recorded over an average of 5 days. A significant correlation was established between the clinical manifestations of brainstem compression and sinus arrhythmias, multifocal premature ventricular contractions, couplets, and ventricular tachycardias. An explanation for this correlation may be found in the localization of the autonomous cardiovascular centers in the hypothalamus and brainstem. Transtentorial herniation frequently leads to a bilateral lesion of these structures. However, the cardiac arrhythmias are only a partial phenomenon within a complex cardiovascular reaction.

Adult↗
PubMed1987

[Mistaken diagnosis in subarachnoid bleeding. A study of 154 cases].

In 154 patients with spontaneous subarachnoid hemorrhage owing to a ruptured aneurysm, the way by which the diagnosis was arrived at was checked. The correct diagnosis was missed initially in 52 patients (33.8%) and the subarachnoid hemorrhage was misinterpreted most frequently as systemic infection, brain tumor, disorder of cerebral blood flow or cervical spinal syndrome. The proportion of false diagnosis was especially high in younger patients with an initially less severe illness. Freely practicing physicians without specialist neurological training missed the diagnosis in 33.3%, free practicing specialists for nervous diseases and neurologists in 17.4%, doctors at smaller hospitals in 16.3% and doctors at the Neurologic Division, University Hospital for Nervous Diseases in Homburg/Saar in 6.5%. The time up to correction of a wrong initial diagnosis was up to seven days in 34 patients (65.4%), up to 14 days in 13 patients (25.0%) and between 15 and 27 days in five patients (9.6%).

Adolescent↗
PubMed1986

[Neurogenic cardiac arrhythmias in acute intracranial increase in pressure (recurrent hemorrhage in subarachnoid hemorrhages)].

Neurogenic cardiac arrhythmias during 5 cases of subarachnoid rebleeding in 4 patients were analyzed by using long-term ECG (Holter). The initial onset of rebleeding was characterized by an abrupt decrease of heart rate from 93.3 +/- 7.85 (beats/min) to 63.3 +/- 14.6 (beats/min). This was immediately followed by pronounced tachycardia of 163.0 +/- 20.9 (beats/min) and subsequently, alterations of the P wave, ST depression with an increase in T wave amplitude. Frequent premature ventricular contractions, couplets, and self-terminating episodes of ventricular tachycardia for 2-8 minutes were observed during 2 episodes of rebleeding, an idioventricular rhythm in one case. The ECG returned to normal in the 3 non-lethal cases. Pathogenetically, the initial heart rate decrease with varying P wave configuration can be explained through activation of the baroreceptor reflex. Elevated intracranial pressure causes a blood pressure increase thus stimulating the baroreceptors and consequently, the afferent and efferent tracts of the vagus nerve. The sympathicotonus appears to have a modulating effect.

Adult↗
PubMed1986

[Diseases of the central nervous system and cardiac arrhythmias].

Diseases of the central nervous system can result in various cardiac arrhythmias. In some neuromuscular disorders, a distinctive morphologic correlate of such arrhythmias can be found as a secondary cardiomyopathy. In other intracranial diseases, in particular subarachnoid and intracerebral hemorrhages, the lack of gross alterations of cardiac morphology suggests some "functional" nature of rhythm disturbances. Lesions of the autonomic regulatory centres frequently cause (unilateral) autonomic imbalance that is projected to the heart according to its asymmetric peripheral sympathetic innervation. The resultant propensity for sympathetically mediated arrhythmias is frequently reflected in prolongation of the QT interval and can be accentuated by simultaneous vagal discharge as well as catecholamine-mediated disseminated myocardial necroses. It is, however, unlikely that such neurogenic arrhythmias bear any independent prognostic significance; on the contrary, prognosis is usually determined by the severity of the underlying neurologic disease and its complications.

Arrhythmias, Cardiac↗
PubMed1985

Direct evidence of hypertension and the possible role of post-menopause oestrogen deficiency in the pathogenesis of berry aneurysms.

To determine the significance of hypertension in the pathogenesis of berry aneurysms, 113 patients with subarachnoid haemorrhage (SAH) and verified aneurysm and 63 patients with SAH without aneurysm were compared. Of those patients with angiographically verified aneurysms, 61.9% were found to have elevated blood pressure (greater than 160/95 mmHg) and 19.5% showed electrocardiographic signs of left ventricular hypertrophy (SV1 + RV5 (6) greater than 3.5 mV). The percentages for patients without aneurysm were 36.5% and 6.4% respectively. A significant correlation was found between anterior aneurysms and left ventricular hypertrophy (P less than 0.01). The mean Sokolow index values were also significantly elevated in cases of aneurysm (P less than 0.01). There was a complementary relationship between the extent of left ventricular hypertrophy and the percentage of females with regard to localization of an aneurysm and age group. The predominance of females in the total aneurysm population, in the 50- to 59-year-old age group, and among patients with internal carotid aneurysms indicates that a sex-specific hormonal factor may also play a role in the pathogenesis of aneurysms in addition to hypertension. The collagen wasting commonly observed in bone and skin in the post-menopausal period due to decreased oestrogen levels could possibly be responsible for the formation of aneurysms in the proximal segments of the cerebral arteries, as occurs in various connective tissue diseases.

Adult↗