Effect of various aminoglycoside antibiotics on glucose formation in isolated rabbit kidney-cortex tubules

The effect of six aminoglycoside antibiotics on the rate of gluconeogenesis was studied in isolated rabbit kidney-cortex tubules incubated with various substrates. All antibiotics studied did not affect glucose formation from both malate and 2-oxoglutarate. The rank order of the drug-induced inhibition of glucose formation from lactate, pyruvate and propionate was the following: neomycin = gentamicin greater than tobramycin greater than kanamycin = amikacin greater than streptomycin. This in principle corresponds to their ability to diminish pyruvate carboxylation in isolated kidney-cortex mitochondria, as well as to their known nephrotoxic potential observed in vivo. Aminoglycoside antibiotics decreased the respiration of tubule suspension incubated with various substrates. However, the rank order of the inhibition by antibiotics of oxygen uptake was different from that observed for gluconeogenesis, suggesting that the rate of energy generation does not limit glucose formation under conditions studied.

[Computerized tomography and infusion test as a simultaneous study method in post-traumatic hydrocephalus]

The cerebral compression of a patient with posttraumatic hydrocephalus was measured intraventricularly, and an intrathecas infusion test was made simultaneously with computed tomography. Substractive computed tomography pictures show that continuously increasing volume does not imply uniform enlargement of the ventricular system, the cornua of the lateral ventricles in particular exhibiting a frontal increase in size.

Inhibitory effect of gentamicin on gluconeogenesis from pyruvate, propionate, and lactate in isolated rabbit kidney-cortex tubules

The effect of gentamicin on glucose production in isolated rabbit renal tubules was studied with lactate, propionate, malate, 2-oxoglutarate, and succinate as substrates. This antibiotic at 5 mM concentration inhibited gluconeogenesis from lactate by about 60% and that from either pyruvate or propionate by about 30%. In contrast, it did not alter the rate of glucose formation from other substrates studied. The rate of gluconeogenesis was higher at 1 mM propionate than at increasing concentrations of this substrate and was stimulated in the presence of 1 mM carnitine. However, the addition of carnitine did not affect the degree of inhibition of glucose formation by gentamicin. Since the mitochondrial free coenzyme A level was significantly lower in the presence of 10 than 1 mM propionate and increased on the addition of carnitine to the reaction medium, the inhibitory effect of propionate concentrations above 1 mM on gluconeogenesis in rabbit renal tubules may be due to a depletion of the free mitochondrial coenzyme A level, resulting in an inhibition of the mitochondrial coenzyme A-dependent reactions. In intact rabbit kidney cortex mitochondria incubated in State 4 as well as in Triton X-100-treated mitochondria, 5 mM gentamicin inhibited by about 30-40% the incorporation of 14CO2 into both pyruvate and propionate. The results indicate that the inhibitory effect of gentamicin on glucose formation in isolated kidney tubules incubated with lactate, pyruvate, or propionate is likely due to a decrease of the rate of carboxylation reactions.

[Spectral analyses in ocular microtremor in disorders of brain stem function]

In 61 healthy and 79 patients the small involuntary movements were recorded using a piezoelecric strain gauge transducer mounted on a modified optical frame. The recording was followed by a spectralanalytic process with special programs. We used a detailed neurological examination for estimating the clinical condition of the patients. The spectral analysis of the ocular microtremor supplies results which correspond to the clinical condition in each case of the patients with increased central herniation. A irreversible loss of cerebral function (brain death) can also be documented. Patients with special clinical syndromes show tremograms which answer the probably extent of damage of (meso-)pontine parts. We investigated and discussed effects of the influence of central-nervous drugs, age-dependent relations, the significance of cardiovascular pulsations and questions and questions of the comparability of findings between both bulbi. The ocular microtremor shows burst-like components with a frequency peak between 60 and 90 oscillations per second. At present must be assessed that it could be a potential monitor of the function of the reticular (meso-)pontine formation.

Enzyme-linked immunosorbent assay (ELISA) for the detection and differentiation of Clostridium botulinum toxins type A and B

Affinity chromatography has been used for a two-step purification of commercial horse botulinum antitoxic globulins type A and B. The first step performed using CH-Sepharose 4B conjugated to toxin type A (or B), permitted the removal of non-botulinal antibodies from antitoxic globulin type A (or B). The anti-botulinal antibodies obtained from the first step were cross-absorbed in the second affinity chromatography using CH-Sepharose 4B conjugated to toxin B (for the purification of antibodies to type A) or to toxin A (for antibodies to type B). The antibodies obtained were used to coat polystyrene wells in an ELISA for the detection of botulinum toxin type A and type B. The first purification step increases the sensitivity of such an ELISA whereas the second step improved the specificity of the test. Only slight cross-reactions were observed between the type A and type B detection systems. The sensitivity achieved with ELISA was 100 and 300 DLM (dosis lethalis minima) for type A and B respectively.

Substrate-dependent effect of 1-34 human parathyroid hormone fragment, dibutyryl cAMP and cAMP on gluconeogenesis in rabbit renal tubules

In the presence of 0.5 mM extracellular Ca2+ concentration both 1-34 human parathyroid hormone fragment (0.5 micrograms/ml) as well as 0.1 mM dibutyryl cAMP stimulated gluconeogenesis from lactate in renal tubules isolated from fed rabbits. However, these two compounds did not affect glucose synthesis from pyruvate as substrate. When 2.5 mM Ca2+ was present the stimulatory effect of the hormone fragment on gluconeogenesis from lactate was not detected but dibutyryl cAMP increased markedly the rate of glucose formation from lactate, dihydroxyacetone and glutamate, and inhibited this process from pyruvate and malate. Moreover, dibutyryl cAMP was ineffective in the presence of either 2-oxoglutarate or fructose as substrate. Similar changes in glucose formation were caused by 0.1 mM cAMP. As concluded from the 'crossover' plot the stimulatory effect of dibutyryl cAMP on glucose formation from lactate may result from an acceleration of pyruvate carboxylation due to an increase of intramitochondrial acetyl-CoA, while an inhibition by this compound of gluconeogenesis from pyruvate is likely due to an elevation of mitochondrial NADH/NAD+ ratio, resulting in a decrease of generation of oxaloacetate, the substrate of phosphoenolpyruvate carboxykinase. Dibutyryl cAMP decreased the conversion of fracture 1,6-bisphosphate to fructose 6-phosphate in the presence of both substrates which may be secondary to an inhibition of fructose 1,6-bisphosphatase.

Density-dependent survival of Ehrlich ascites tumour cells in the presence of various substrates for energy metabolism

We have found that Ehrlich ascites tumour (EAT) cells, deprived of any carbon source, and suspended at a density of 2 X 10(5) cells/cm3, begin to die only after 12 h of starvation, though it is known that under these conditions they lose over 80% of their ATP within 30 min. Moreover, we have found that the viability of the cells incubated in the absence of any substrate for energy metabolism is strongly dependent on the density of the cell suspension, and can be significantly improved simply by increasing the suspension density. This prompted us to investigate the density dependence of the maintenance of EAT cell viability in the presence of various substrates for energy metabolism and metabolic intermediates. It was found that: Glucose ensures 48 h viability of EAT cells irrespective of suspension density. Fatty acids and pyruvate as sole carbon source do not improve EAT cell survival. In the presence of glutamine as sole carbon source the EAT cell survival shows dependence on cell-suspension density. At densities of 1.6 X 10(6) to 3.2 X 10(6) cells/cm3 the cell viability is maintained at least as well as in the presence of glucose, but at low cell-suspension densities glutamine does not support cell viability. In the presence of glutamine, addition of 1 mM-inosine and 1 mM-uridine ensures high cell survival irrespective of the cell-suspension density. In the presence of inosine or uridine (10 mM) as sole carbon source, the EAT cell survival is the same as in the presence of glucose and does not depend upon cell-suspension density. Guanosine is less effective, whereas adenosine has no effect at all on the maintenance of EAT cell viability for 48 h. There is no correlation at all between EAT cell survival and the rate of lactic acid production. At a cell-suspension density of 1.6 X 10(6) cells/cm3 the cell survival is of the same order in the presence of glutamine as in the presence of glucose, in spite of the fact that in the first case the rate of lactic acid production is more than 20 times lower. There is no correlation between the capacity of particular nucleosides to support EAT cell survival and their effects on glycolysis and oxygen consumption.

[Standardized monitoring of brain function]

A form is described for recording the results obtained when monitoring the brain function in cases of severe acute brain damage. The form follows the principles introduced in other countries for recording the results of similar standard examinations, but the symptoms and scalings have been modified to suit the author's requirements. The state consciousness as shown by the opening of the eyes, verbal response and motor reactions to various stimuli is considered essential for the continuous monitoring of the brain function, as are also the dilation of the pupile and their response to light and the vestibuloocular reaction. The form also contains entries for respiration, blood pressure, heart rate and body temperature. The neurological symptoms have been selected on the basis of their diagnostic value, consistency and simplicity of examination and interpretation. The advantages of a standard examination scheme are explained. Advice is given regarding the examination of the different symptoms.

[The significance of computerized tomography for the diagnosis of cerebral venous and sinus thromboses]

Thromboses of cerebral veins and sinus occur both in childhood and in adult age. The clinical symptoms are variable, so that until a few years ago the diagnosis had been based exclusively on angjiography. Owing to the introduction of computer tomography, a method has now become available to the clinician which, while it does not involve great risks and stress for the patient, is of great importance in the diagnosis of thromboses of cerebral veins and sinus, especially for the observation of the course of the disease and the therapy to be employed. This is particularly true of the indication for thrombolytic and anticoagulant therapy. The computertomographic findings are described on the basis of the literature and two own observations, differentiating between direct and indirect symptoms. All changes are inconstant, which makes the appraisal difficult. At the time being, the angiographic diagnosis can rarely be renounced. Both examination methods supplement each other very well.

[The significance of computer tomography for the diagnosis of stroke]

Today, the extension of the diagnosis of apoplexy by the employment of computer tomography is part of an important field of indications for this examination method. Experience in this respect could be obtained from a total of 1,500 patients with a share of 105 cases presenting cerebral blood supply disturbances. The unproblematic differentiation of mass haemorrhages and cerebral infarctions including the possibility of an exact assessment of the process dynamics proved to be diagnostically just as important as the differential diagnostics of intracranial haemorrhages of other origins, such as occur after a rupture of aneurysms and angiomas as well as tumour haemorrhages.

[Current aspects of neurocysticercosis. Clinical and pathological report on 3 cases]

This is a clinical and pathological report on three cases (one 48-year-old male, one 57-year-old female, and one 59-year-old male) of neurocysticercosis where postmortem examinations were made between 1972 and 1974. In all of these three cases invasion of the body by the larva of Taenia solium and, more specifically, of the interpeduncular cisterns had led to chronic lymphocytic and granulomatous leptomeningitis and severe hydrocephalus. Complicating the disease picture in one case each were an occlusive granular ependymitis in the aqueduct and a nonspecific endangiitis. The great importance of liquor eosinophilia to the clinical diagnosis of neurocysticercosis is again demonstrated by reference to these cases. The complement fixation reaction is recommended as the most reliable method of diagnosing. This should be should in all ases of etiologically uncertain chronic leptomeningitis