Biomedical subjects
Publications and source records attributed to L Auer.
Report on seven cases of severe head injury, where proteolytic enzyme activity in the ventricular fluid was measured within a period of eight days. The result was positive in four cases. This finding is discussed in relation to clinical features and morphology. Earlier reports and these results are considered.
It is not only for CSF-removal in conservative treatment of oedema and control of the effectiveness of osmo-onco-therapy, contricosteroids, anticholinergics and aldosterone-antagonists, that external CSF drainage in severe cerebral trauma has proved of value. It has also made it possible to assess objectively the indications for bitemporal craniotomy in raised intracrainial pressure with an acute midbrain syndrome caused by tentorial herniation. Continuous monitoring of ICP permits an intervention at the right time and prevents one from operating too late, namely at a moment, when manifest neurological signs already indicate cerebral decompensaervative steps failing, a bitemporal craniectomy is indicated: in this way we lower intracranial pressure, liberate the rostral brain stem out of its strangulation and improve cerebral perfusion and metabolism.
In a series in 8 cats, cerebral perfusion pressure (CPP) was evaluated over a period of 5 min after production of an acute arterial hypertension. The mean percentual increase of blood pressure, CPP and ICP equalled 100%. the fact, that ICP does not play any role in acute hypertension, indicates that an abrupt elevation of filtration pressure within the capillaries must be the decisive factor leading to edema.
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In cats, a direct observation of the brain surface was made possible by fenestration. The pial vessels were observed by means of intravital incident-light microscopy. Particular attention was paid to blood pressure, blood pH, pCO2 and pO2. Mainly with diffuse vasodilation (hypotension) the capillaries stood out as a close network. Normally, interarterial anastomoses were rarer than intravenous ones. Arteriovenous anastomoses were not found. The interarterial blood column rarely came to a standstill, the intervenously this was observed frequently. Two kinds of intervenous anastomoses were found: short connections between veins running close to each other and long venules between vessels of different outflow systems.
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Quantitive estimations of serum proteins, including Alpha 2M globulin, from 34 patients suffering from craniocerbral trauma have been carried out. The mean value curves over a period of two weeks following trauma are presented graphically. After severe injuries, depending on the size of the cerebral lesions, an increase in Alpha 2 of prognostic significance has been observed. Levels of Alpha 2M do not correlate directly with Alpha 2 globulin, and tend to fall initially. Falls in the first three days after injury may be prognostically significant from the point of view of the prediction of a lethal outcome. There are no significant changes in the levels of total protein, albumin, Beta globulin or Gamma globulin, but Alpha 1 globulin follows the curve of Alpha 2, although to a less marked degree. Correlations between serum protease activites and increases in Alpha 2 due to enzymatically active complexes are unconnected with Alpha 2M, a decrease in which indicates increased inhibitor activity and exhaustion of the inhibitor system.
Investigations of serum total protein, albumin, alpha-1, alpha-2, alpha-2M, beta- and gamma-globulin changes are reported in 48 patients with craniocerebral trauma. Only alpha-2 and alpha-2M globulins showed important variations, the first rising to three to four times normal values (112% on average) and directly correlating with the amount of tissue lesions. Alpha-2M changes were rather irregular with a tendency to severe decrease during the first days in patients with a bad prognosis. Reasons for non-regular changes of alpha-2M are discussed. Alpha-1 globulin showed a similar though less marked increase. Gamma globulin, on average, was diminished in the first week.
The Anti-G-Suit- an over-all-air-pressure-garment over legs and bowel up to the xiphoid is proposed as a successful method to encounter acute postural decrease of blood pressure in neurosurgical patients. Increase of peripheral resistance and displacement of the circulating blood volume above the diaphragm enhance blood pressure which has fallen by the depressive effect on the vasomotor centre and the negative inotrope effect of narcotics.
The aim of this paper is to contrast new results obtained on the activities of lysosomal proteases in the brain of traumatized animals with the previously held opinions concerning the development of post-traumatic brain oedema. Two hours after a standardized head injury in the cat, acid and neutral proteases were determined in the brain homogenate. Total as well as free activity, especially of the neutral proteases, were markedly increased after head injury, a circumstance indicating the important role of lysosomes in the development of post-traumatic brain oedema. It is postulated that not hypoxia alone, but primary or secondary disturbance of lysosomal function is the predominant factor in the development of brain oedema. Release of enzymes -- especially proteases -- causes irreversibility of initial vascular oedema by autolysis of cellular structures.
The use of the "Anti-G-Suit" in patients with postural hypotension is described. Acute falls in the blood pressure during operations in the sitting position can be successfully treated with the aid of an external counterpressure garment reaching from ankles to xiphoid process. The mean increase in systolic blood pressure was about 60% in hypotensive and 17% in normotensive control patients. A reciprocal relation between pre-treatment blood pressure and its increase after use of the "G-Suit" was noticed. In contrast to previous practice, we were able to operate on all hypotensive patients in poor condition. The effect of external counterpressure on the lower part of the body can be explained by increase of peripheral resistance and decrease of vascular flow, resulting in better venous return, displacement of the circulating blood above the diaphragm and augmentation of systolic blood pressure.
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Superior sagittal sinus pressure, intracranial pressure and arterial pressure were recorded in an experimental series on 10 cats. During drug-induced, severe, acute arterial hypertension and parallel hypercapnia, venous pressure could exceed intracranial pressure in both the supra- and infratentorial compartment. From these data it is concluded that cerebral venous pressure during acute arterial hypertension may contribute to protein extravasation at the postcapillary-venular level.
Using an experimental design permitting generation of a pulsatile "flow-velocity waveform" corresponding to the fetal aortic signal, the influence of measurement depth, the angle between the Doppler beam and the vessel, the high-pass filter and the extent of overlap between the "sample volume" and the vessel cross-section were studied in vitro. The Resistance Index showed the best relation to inductive flow measurement, which was defined as standard. Considering the conditions prevailing during clinical studies, good reliability is likely at angles of between 0 degrees and 60 degrees (120 degrees-180 degrees) over the entire range of measuring depths (4-13 cm) and when using 100-200 Hz high-pass filters. The magnitude and location of the sample volume does not seem to play a decisive role provided a part of it is within the sonographically imaged "vessel" and there is no likelihood of interference from vessels in the immediate vicinity in which blood flow is in the same direction.
The aim of the study communicated here was to check any fetal reactions occurring after external stimulation (light-optic and acoustic stimuli), depending on fetal behavioral status. The group studied (acoustic/light stimulation) comprised 85 patients with normal course of pregnancy at term (37th to 42nd week of gestation). They were compared with a control group of nonstimulated patients (n = 26), also with normal course of pregnancy and corresponding gestational age. Fetal heart frequencies and an external tokogram were recorded synchronously with the fetal respiration, body, limb and eye movements registered simultaneously by two independent observers and the fetal behavioral statuses were defined (Nijhuis, Prechtl et al. 1982; Boos and Schmidt 1984; van Vliet et al. 1985). The stimulation methods used were as follows: 1. Single-frequency pure tone (2 kHz, 120 dB, 5 sec) 2. Sawtooth-modulated pure tone (0.5-2.0 kHz, modulation frequency 10 Hz, 120 dB, 5 sec) 3. Low-frequency, sawtooth-modulated pure tone (with vibration effect), (0.1-0.3 kHz, modulation frequency 10 Hz, 120 dB, 5 sec) 4. Light stimulation: electronic photographic flash, luminous intensity 25 X 10(6) Lux/10(-3) sec, 8 flash sequences in 10 sec, distance from maternal abdomen 20 cm. In order to rule out purely coincidental changes in fetal attitude, both genuine and "sham" stimulations were performed in randomized sequence, in the latter case without any acoustic or light-optic signals. No differences in fetal reactions were found with the three different acoustic stimulation methods.(ABSTRACT TRUNCATED AT 250 WORDS)
In an experimental series on twelve cats, activity changes of brain cell proteolytic activity were measured two hours after a blunt head injury without hematoma or contusions. Protease activity was estimated in two different brain tissue homogenate supernatants containing total soluble and only cytoplasmic activity without proteases in cell organelles, respectively. Total activity was doubled two hours after injury in the acid and the neural pH-range, in comparison to control values. Free soluble activity was doubled in the acid and increased to the threefold value in the neutral range. From these data, it seems that two different changes appear in lysosomes, the enzyme-reservoir of the cell: (1) Enzyme-synthesis is increased after trauma, measured as augmentation of total soluble protease activity in our experiments; (2) Breakage or increased permeability of lysosomes lead to augmentation of especially neutral proteases in the cytoplasm followed by the well known autolytic areas of generalized traumatic brain edema.
We present the results and experiences with a prototype cardiotocograph with US-autocorrelation processing. As this method is fundamentally different from conventional signal processing we are entering into the particular problems of this new FHR-technology. A total of 70 antepartum fetal rate recording from 53 patients and 38 intrapartum CTGs were evaluated. The antepartum results were excellent, the application time could be minimized and the quality of the recordings has been essentially improved. With the intrapartum recordings a computer comparison of long and short time irregularity of FHR derived from US-autocorrelation and direct fetal EKG was performed. The results proofed an excellent approximation to beat-to beat recording using the US-autocorrelation technique. The idea of using the new method intrapartum instead of invasive CTG could not be realised. This was due to a increasing loss of signal with progress of labor. To exclude maternal HR interferences the new monitor is supposed to record maternal heart rate simultaneously to FHR.