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Biomedical subjects

H Stephan

Publications and source records attributed to H Stephan.

At least 55 records · Page 3Linked to original sources
PubMed1985

Volume comparisons in the cerebellar complex of primates. I. Ventral pons.

Volumes of the ventral pons (VPo) were measured in 82 brains of primates, Scandentia, and Insectivora, and the relative size of the VPo was expressed by size indices. The reference line was through the prosimian average; the mean index of prosimians was set at 1. The taxonomic groups arranged in a sequence of ascending mean VPo indices were: Insectivora (0.04), prosimians (1.00), monkeys (2.55), apes (4.48) and man (9.44). Thus, the VPo of man is more than 9 times larger than that of isoponderous average prosimians, and more than 230 times larger than that of isoponderous "basal' insectivores. The indices may reflect trends and extent of VPo evolution in primate phylogeny.

Animals↗
PubMed1985

Volume comparisons in the cerebellar complex of primates. II. Cerebellar nuclei.

Volumes of medial, interposed, and lateral cerebellar nuclei (MCN, ICN, and LCN) were measured in Insectivora, Scandentia, and Primates, including man. The relative size of the nuclei was expressed in size indices. Insectivora had by far the smallest cerebellar nuclei. The simians, in general, had larger cerebellar nuclei than the prosimians, but there was considerable overlap. From Insectivora to man, the MCN was the least progressive and the LCN the most progressive. The indices are expected to reflect the relative size of the three longitudinal zones of the cerebellum (vermis/MCN, pars intermedius/ICN, hemisphere/LCN). They, together with those of the ventral pons and cerebellum (part I), are discussed in relation to the predominant locomotor pattern of a species, and with reference to evolutionary trends in primate phylogeny.

Animals↗
PubMed1985

[Cardiovascular effects of isoflurane-nitrous oxide anesthesia in peripheral and abdominal surgical interventions].

The cardiovascular actions of isoflurane-nitrous oxide anesthesia were studied in 20 patients (age rage 46-76 yr) undergoing laparatomy (group A = 13 patients) or peripheral vascular surgery (group B = 7 patients). Measurements were performed in the awake state, 20 min after induction of anesthesia and during surgical stimulation. Isoflurane produced small changes in heart rate but a significant reduction in mean arterial pressure which was due to a reduction in peripheral vascular resistance and myocardial contractility. During surgical stimulation arterial pressure rose above control values in group A but remained below control in group B. Cardiac index and stroke volume index both decreased after induction of anesthesia in group A and B. During surgical stimulation cardiac index increased in group A due to an increase in heart rate but remained below control in group B, while stroke volume index was reduced in both groups throughout the whole procedure. These results suggest, that contrary to the findings in human volunteers, isoflurane produces a significant cardiovascular depression in aged surgical patient.

Abdomen↗
PubMed1985

[The effect of rewarming of stored blood on plasma value and erythrocytes].

30 units of stored blood of different age were rewarmed from 4 degrees C to 32 degrees C by microwave blood-warmer Infusotherm 407. The resulting damage to blood components and change of function of erythrocytes were compared with those caused by storage of CPD-blood. Dependent on the age of stored blood we found considerable increases in the plasma-levels of potassium, lactate, and free haemoglobin. Compared with cold CPD-blood rewarming of stored blood produced a 7% increase in lactate and a 8% increase in free haemoglobin. There were no changes in platelet and erythrocyte counts, haematocrit, plasma-levels of haemoglobin, electrolytes, cholesterol, blood viscosity, osmotic resistance, and oxygen-binding capacity. As damage of stored blood produced by warming is minimal compared with that produced by storage, the Infusotherm 407 is considered to be a clinically useful blood-warmer.

Blood Cell Count↗
PubMed1985

[Signs of myocardial ischemia based on nocturnal circulatory changes in coronary patients].

During one preoperative night blood pressures, heart rates and changes in ST-segments of ECG were measured at hourly intervals in 20 male patients suffering from a two or more coronary vessel disease. In five patients one or more events of increased myocardial ischaemia were seen in the ECG without any of the patients remembering an attack of angina pectoris. The circulatory function during these periods showed no connection between ST-segment-changes and extremely high or low levels of blood pressure and/or heart rate. Therefore from this investigation nothing can be said about borderline levels of blood pressure and heart rate terminating safe anaesthesia.

Adult↗
PubMed1979

A quantitative approach to cytoarchitectonics. IV. The areal pattern of the cortex of Galago demidovii (e. Geoffroy, 1796), (lorisidae, primates).

The boundaries of neo- and allocortical areas of Galago demidovii are analyzed with an automatic quantitative procedure using an image analyzer. The results are summarized in a cortical map and compared with a cortical map of Tupaia. Galago shows a highly differentiated temporal lobe and no homogeneous peristriate area comparable to the classical concept of Brodmann's Area 19. Primary motor, somatosensory, auditory, and visual areas are delineated and shown to be surrounded by distinct secondary areas.

Animals↗
PubMed1978

Transfer of bovine J-blood-group determinant onto erythrocytes: isolation and identification of a blocker.

The bovine J-blood-group determinant is transferred from a serum glycoprotein to an erythrocyte membrane lipid by incubation in vitro. This transfer is inhibited by a lipid (called 'blocker') occurring in bovine and human serum, in other bovine and human tissues, yeast and plant tissues. The blocker was isolated from bovine spleen and identified as phosphatidylserine. Moreover, phosphatidylinositol acts as a blocker, while a variety of other phospholipids, glycosphingolipids and neutral lipids have no function as blockers. Mild alkaline deacylation deletes the blocker activity of both phosphatidylserine and phosphatidylinositol. Methyl esters of these phospholipids, or exchange of the amino group for a hydroxyl group in phosphatidylserine or N-benzoylation of phosphatidylserine, do not affect the blocker function. The blocker function of phosphatidylinositol is lost after periodate oxidation. The blocker reacts with the J-containing serum protein, not with the erythrocyte membrane. After preincubation of the J-positive serum protein with the blocker and reextraction of excess blocker, the serum protein remains J-positive, but is then unable to transfer the J determinant to the erythrocyte membrane.

Animals↗
PubMed1977

Quantitative comparison of the amygdala in insectivores and primates.

Comparative architectonic studies have resulted in a classification of the amygdaloid complex which differs somewhat from the commonly used classification (first proposed by Humphrey, 1936) by separating the cortical amygdaloid nucleus from the centromedial group and assigning it to the basolateral group, which then forms a cortico-basolateral group. The size changes of these groups and of the nucleus of the lateral olfactory tract (belonging to the centromedial group) and the large-celled part of the basal nucleus (belonging to the corticobasolateral group) have been investigated in representatives of an ascending primate scale. In all structural complexes investigated so far, the small-celled part of the cortico-basolateral group is the most progressive. In descending order of progression there follow: the corticobasolateral group as a whole, the amygdala as a whole, and the large-celled basal nucleus. No clear changes were found in the centromedial group as a whole, whereas the size of the nucleus of the lateral olfactory tract, which represents a small component of this latter group, shows a strong reduction. These differences in the developmental trends point to increasing or decreasing capacities of the functional (limbic and olfactory) systems, to which these structures are related.

Amygdala↗
PubMed1976

[Comparative volumetry of brains from wild and captive tree shrews (Tupaia)].

The changes in brain weight and composition during captivity were investigated in two groups of tree-shrews (Tupaia). One group consisted of wild animals whose brains were dissected and weighed immediately after trapping in Thailand. The second group (F1) consisted of animals reared in captivity whose parents originated from the same populations of Thailand animals as the first group. Wild- and F1-animals showed no significanct differences in body weight; however, the brain weight was significantly greater in F1-animals. This is in clear contrast to the results of former investigations of other species, in which the brain size became reduced in captivity. Of the various brain parts, the absolute volumes of the cerebellum and the telencephalon, and, within the latter, those of the striatum, schizocortex, neocortex, and area striata were enlarged significantly in animals reared in captivity. A significant decrease was observed in the complex of paleocortex + amygdala, and a possible decrease in the hippocampus. An attempt to interpret the changes was made with regard to differences in age-composition between the two groups, different nutrition and motor activities, heterochronies in the ontogenetic development, and, finally, different environmental influences during ontogeny.

Age Factors↗