Biomedical subjects

E Theodorsson

Publications and source records attributed to E Theodorsson.

239 records · Page 14Linked to original sources

PubMedDate not supplied

BASIC computer program to summarize data using nonparametric and parametric statistics including Anderson-Darling test for normality.

Tools for calculating Gaussian parametric statistics are widely available in hand-held calculators and program packages for desktop as well as mainframe computers. The standard deviation calculated from non-Gaussian data may, however, be meaningless or even absurd. Furthermore, the standard error of the mean is frequently used as a descriptive statistic even if it really does not describe the variation in the observations themselves. However, comprehensive tools for calculating nonparametric descriptive statistics and judging whether observations have a Gaussian distribution are hard to come by. The present paper attempts to provide the essential statistical reasoning behind the calculation of descriptive statistics and introduces a computer program written in Microsoft BASIC that applies the methods described in the text.

Mathematical Computing↗

PubMedDate not supplied

Microwave irradiation increases recovery of neuropeptides from brain tissues.

The effect of focused high energy microwave treatment (MW) on brain concentrations and molecular forms of substance P, neurokinin A, neuropeptide Y, neurotensin, galanin and calcitonin gene-related peptide was investigated. Groups of rats were treated as follows: 1) MW, storage for 60 min at 22 degrees C, 2) Decapitation, storage for 60 min at 22 degrees C. 3) Decapitation, storage for 60 min at 22 degrees C, MW treatment, 4) MW, decapitation, storage for 2 min at 22 degrees C and 5) Decapitation, storage for 2 min at 22 degrees C. Peptide concentrations were in all instances highest in the MW sacrificed groups. MW increased the concentration of intact peptides by rapid inhibition of peptidase activity and increase in peptide solubility/extractability.

Animals↗

PubMedDate not supplied

Intracerebroventricular infusion of nerve growth factor in three patients with Alzheimer's disease.

Nerve growth factor (NGF) is important for the survival and maintenance of central cholinergic neurons, a signalling system impaired in Alzheimer's disease. We have treated 3 patients with Alzheimer's disease with a total of 6.6 mg NGF administered continuously into the lateral cerebral ventricle for 3 months in the first 2 patients and a total of 0.55 mg for 3 shorter periods in the third patient. The patients were extensively evaluated with clinical, neuropsychological, neurophysiological and neuroradiological techniques. Three months after the NGF treatment ended, a significant increase in nicotine binding was found in several brain areas in the first 2 patients and in the hippocampus in the third patient as studied by positron emission tomography. A clear cognitive amelioration could not be demonstrated, although a few neuropsychology tests showed slight improvements. The amount of slow-wave cortical activity as studied by electroencephalography was reduced in the first 2 patients. Two negative side effects occurred with NGF treatment: first, a dull, constant back pain was observed in all 3 patients, which in 1 patient was aggravated by axial loading resulting in sharp, shooting pain of short duration. When stopping the NGF infusion, the pain disappeared within a couple of days. Reducing the dose of NGF lessened the pain. Secondly, a marked weight reduction during the infusion with a clear weight gain after ending the infusion was seen in the first 2 patients. We conclude from this limited trial that, while long-term intracerebroventricular NGF administration may cause certain potentially beneficial effects, the intraventricular route of administration is also associated with negative side effects that appear to outweigh the positive effects of the present protocol. Alternative routes of administration, and/or lower doses of NGF, perhaps combined with low doses of other neurotrophic factors, may shift this balance in favor of positive effects.

Aged↗

PubMedDate not supplied

Antidiuretic hormone regulation in hemodialysis.

The relative influence of stimulation and suppression of osmoreceptors and low and high pressure baroreceptors was studied in 12 patients on hemodialysis. The stimuli were separated by ultrafiltration and dialysis. When high and low baroreceptors were deloaded by volume contraction during ultrafiltration, but there was no change in osmolality, the antidiuretic hormone (ADH) level rose steeply. When osmoreceptors were suppressed, but there was no influence on baroreceptors during dialysis, ADH level declined by the same amount it had increased during ultrafiltration. When osmoreceptors were stimulated by an increase in osmolality in the phase between dialyses, but baroreceptors were loaded by an increase in volume, ADH levels did not change. Others showed that when baroreceptors are stimulated and osmoreceptors suppressed during simultaneous ultrafiltration and dialysis, there is also no change in ADH levels. These results indicate that the hierarchy of receptors regulating ADH is osmoreceptors followed by high and low baroreceptors. Simultaneous stimulation or suppression of both baroreceptors appears equal to the influence by osmoreceptors.

Blood Pressure↗

PubMedDate not supplied

Autoradiographic quantitation and anatomical mapping of 125I-galanin binding sites in the rat central nervous system.

The distribution of 125I-galanin binding sites in the rat central nervous system was studied by the use of autoradiography, and the amount of peptide bound was determined by the use of microdensitometry. The amount of 125I-galanin bound in various CNS regions ranged from non detectable to 0.40 pmol per gramme tissue at a concentration of 1.5 nM 125I-galanin. The anatomical mapping revealed high density of binding sites in the telencephalon, where labelling was seen in the entorhinal, perirhinal and piriform cortices, in most septal nuclei, in the amygdala and in the hippocampal formation. In the diencephalon binding sites were densely accumulated in the hypothalamus, including the median eminence and periventricular nucleus as well as in the dorsal and medial thalamic nuclei. In the mesencephalon binding sites were seen in many nuclei including the dorsal raphe nucleus, the periaqueductal central grey and pars compacta of the substantia nigra. The pons/medulla revealed high density of binding sites in the locus coeruleus, parabrachial nuclei and in the dorsal vagal complex, while binding in the spinal cord was seen in laminae I, II and X as well as in the intermediolateral horn. The distribution of 125I-galanin binding sites corresponded well to the localization of the peptide as revealed in several earlier immunohistochemical and radioimmunoassay studies, as well as to several previously reported effects of galanin on central autonomic functions.

Animals↗