Slight Deficit Research Articles

Frontal eye field lesions impair predictive and visually-guided pursuit eye movements

The study initially explored the frontal eye field's (FEF) control of predictive eye movements, i.e., eye movements driven by previous rather than current sensory signals. Five monkeys were trained to pursue horizontal target motion, including sinusoidal targets and "random-walk" targets which sometimes deviated from a sine motion. Some subjects also tracked other target trajectories and optokinetic motion. FEF ablations or cold lesions impaired predictive pursuit, but also degraded visually guided foveal pursuit of all targets. Unilateral lesions impaired pursuit of targets moving in both horizontal orbital fields and in both directions of movement. Saccadic estimates of target motion were generally accurate. The slow-phase velocity of optokinetic pursuit (collected after 54 s of OKN) also appeared normal. Pursuit recovered over 1-3 weeks after surgery but the deficits were then reinstated by removal of FEF in the other hemisphere. Thereafter, a slight deficit persisted for up to 10 weeks of observation in two subjects. The pattern of symptoms suggests that FEF lies subsequent to parietal area MST and prior to the pontine nuclei in controlling pursuit eye movements.

Nitrogen Leaching Losses from Irrigated Orchardgrass on Sandy Soils

AbstractIrrigated pasture may provide an alternative forage source for livestock producers in Nebraska's Sandhills. As with any heavily fertilized crop, there is a significant potential for groundwater contamination by nitrate nitrogen (NO3‐N) leached from the crop root zone. A 3‐yr experiment was conducted in West Central Nebraska to evaluate water and nitrate (NO−3) leaching losses from irrigated orchardgrass (Dactylis glomerata L.) seeded on a Valentine fine sand (Typic Ustipsamments). Three irrigation levels (slight deficit, slight excess, and excess) and four N amounts (0, 112, 224, and 336 kg−1) were applied. Deep percolation and NO−3 leaching were measured with Duke‐Haise trough‐type extractors. All irrigation treatments had more deep percolation than expected, as the crop coefficient used for irrigation scheduling proved to be too large. The deficit irrigation treatment served as a “close management” treatment since percolation was minimal and yield was not reduced by water stress. During the first 2 yr of operation, in‐season percolation losses averaged 7, 28, and 47 cm yr−1 for low, medium, and high irrigation levels, respectively. Total in‐season NO3‐N leaching loss for the same period ranged from 6 to 228 kg ha−1, depending on N and irrigation amount. Winter and early spring N leaching losses, as estimated by soil sampling, were a significant part of total N loss. Under reduced inseason drainage and an N rate commensurate with 80 to 85% of maximum production, a minimum annual N leaching loss of 35 kg ha−1 can be expected. Greater losses are probable under average water and N applications and average management skills.

Medial dorsal thalamic lesions and working memory in the rat

Pigmented rats of the DA strain with either radiofrequency or ibotenic acid lesions of the thalamic nucleus medialis dorsalis were postoperatively given nonspatial and spatial tests of working memory. In the nonspatial task, delayed nonmatching-to-sample, rats with both types of thalamic lesions showed acquisition impairments. The subgroup of rats with nucleus medialis dorsalis lesions that were able to reach the acquisition criterion did, however, perform normally when the retention interval was extended to 60 s. In the spatial task, delayed forced-alternation, rats were tested with differing retention intervals and with both spaced and massed trials. Damage to nucleus medialis dorsalis had no effect on acquisition or on spaced trials, but a slight deficit was found in the animals with radiofrequency lesions under the massed trial condition. Much clearer deficits were, however, present in those animals in which the lesion extended appreciably into the anterior thalamic nuclei. The findings indicate that while cellular damage to nucleus medialis dorsalis may disrupt learning, some impairments in tests of spatial working memory attributed to this nucleus may reflect damage to the adjacent anterior thalamic nuclei.

Medical and surgical treatment of intracerebellar haematomas

15 cases of intracerebellar haematomas [11 spontaneous, 2 traumatic and 2 unclear] were presented. Hypertension was thought to be a main risk factor in 91% in 11 of the spontaneous cases. 11 cases were treated medically. They were usually conscious, scoring not less than 13 in GCS with subacute or chronic picture of illness and harbouring small haematomas below 3 cm in diameter situated almost always in the hemisphere and with no signs of ventricular dilation. Mortality in medically treated patients was 9% [1 case]. The remainder were discharged in good state, usually with no or only slight neurological deficit. Complete haematoma absorption took about 14 days. There were no signs of delayed hydrocephalus in subsequent CT scans. When the haematoma was large, more than 3 cm in diameter, located usually in the vermis or in the vermis and cerebellar hemisphere, sometimes with ventricular involvement, the clinical presentation was acute and required CT diagnosis and surgical evacuation without delay due to low and deteriorating conscious level. Postoperative mortality was 25%, but delayed mortality was 100%. Vertebral angiography was performed in all cases of spontaneous haemorrhage and was normal in 54%, revealed atheromatous changes in 36% and the signs of cerebellar haematoma in only 10%. Arteriovenous malformations were excluded from this study. The authors believe, that the benign course of intracerebellar haematomas is more frequent than it was considered previously and needs no surgical treatment in many cases.

Event-related potential assessment of attention and the orienting reaction in boxers before and after a fight

Boxers' attention and orienting mechanisms were investigated using event-related brain potential recordings, before and after a fight. This study did not reveal any abnormalities of attention or detection processes. However, a slight deficit in the orienting reaction towards stimuli delivered in the right ear, related to a greater number of blows delivered on the left side of the head, was observed.

Early sensory determinants of locomotor speed in adult cats: I. Visual compensation after bilabyrinthectomy in cats and kittens

After a study of locomotion in cats deprived of their vestibular receptors early in life 31, the average speed of locomotion was measured in 3 adult cats, first before and then several months after bilateral labyrinthectomy, in a task involving free locomotion across platforms, rails or ladders and under normal illumination versus stroboscopic illumination or darkness. In the absence of visual cues, cats which received lesions as adults showed, on both wide and narrow supports, the same speed deficits as those of subjects which underwent lesions soon after birth. Visual cues were, however, used by some cats with early lesions to recover near normal performances on wide platforms. Evidence was found that the vestibular deficit comprised at least 3 components: a severe loss of dynamic balance occurred in all subjects with lesions and was mostly not compensated for by vision; a loss of the ability to keep to a straight course in darkness was observed on wide platforms, but vision considerably improved this function, even under stroboscopic illumination; a slight paw adjustment deficit was also observed on irregular supports, due to the fact that vision played a decreased role after the vestibular lesion. These effects point to the specificity of the vestibular control of balance, the availability of several sensorimotor strategies for orientation, and the complementarity of vestibular and visual inputs in guiding the subjects' step. We confirm here that vestibular inputs do not play a critical role during locomotor development, and stress the fact that peripheral visual cues about position or orientation (rather than motion), play a leading role in compensatory strategies.

Concentration Profiles of Platelet‐Sized Latex Beads for Conditions Relevant to Hollow‐Fiber Hemodialyzers

A freeze-capture method was used to obtain the concentration profiles of platelet-sized latex beads (2.5 microns diameter) in saline-based red cell suspensions flowing through tubes with inner diameters of 135 and 200 microns. Without red cells the concentration profile exhibited a slight deficit near the wall. For hematocrits from 15 through 52%, the concentration profile exhibited a near-wall excess of beads, from two to eight times the central concentration. Near-wall excesses were small or nonexistent in the first half centimeter of the tube. For hematocrits of 15 and 30%, the profile and near-wall excess were equal at stations 2 cm or more from the entrance. These results suggest that there is a flow-driven mechanism that moves platelet-sized beads toward, but not to, the wall.

Analysis of deficit irrigation strategies for corn using crop growth simulation

Corn yields for full irrigation and 4 different levels of deficit irrigation were simulated using a model developed by Stockle and Campbell (1985). Different irrigation levels were obtained by holding the application depth constant and allowing the irrigation interval to vary from 1 to 5 days. Silt loam and loamy sand soils, two root depths, two water contents at planting time, total pumping heads ranging from 0 to 800 m, four ratios of energy cost to commodity price and climatic data for the 1974 growing season at Davis, California were examined. The different variable combinations resulted in a wide range of crop water deficit and yield. Results indicated that, for given combinations, slight deficit (ratios of actual to potential transpiration larger than 0.89) provided higher net benefit than full irrigation. Larger deficits were never advantageous across the diverse range of conditions examined, indicating that potential benefits are associated with only a narrow range of irrigation deficits. This result illustrates the risk involved when deficit irrigation is practiced. Large soil water holding capacity, high soil water contents at planting and deep root exploration were found important for successful implementation of deficit irrigation. Total pumping head and the ratio of energy cost to commodity price were important factors in determining the feasibility of deficit irrigation for the conditions examined. It was also found that the level of irrigation which maximized net benefits tended to be lower for situations where the quantity of water available for irrigation was fixed and the amount of land which could be irrigated was unlimited than when there was sufficient water to fully irrigate the entire farm. Situations where deficit irrigation is a more effective way of reducing energy cost than reducing system operating pressure were ob served.

Pericallosal aneurysms

The authors report a series of 19 patients with one (17 cases) or two (2 cases) pericallosal aneurysms referred during the past 10 years. Of the 19 patients, 18 had a ruptured pericallosal aneurysm and one was asymptomatic. On admission two were graded I, four graded II, six graded III, and six graded IV. Of the latter group two patients died from rebleeding, and the asymptomatic patient would not undergo surgery. The 16 operated patients underwent surgery after a delay ranging from 6 to 90 days after hemorrhage (25 days on average). The delayed surgery allowed the patients to be operated on in better neurological status: seven were graded I or Ia, six graded II, three graded III, and none graded IV. The results were excellent (with resumption of their previous activity) in 11 cases (69%), good (autonomous but with a slight deficit) in 4 cases (25%), and bad in 1 case (6%). There was no operative mortality or morbidity.

The effect of pirenzepine on spatial learning in the Morris Water Maze

The effects of the selective M1-muscarinic antagonist, pirenzepine, were studied on the Morris Water Maze, a test of spatial learning in the rat. Pirenzepine (0, 10 or 30 micrograms) was administered into lateral ventricle during acquisition of this task. Although 30 micrograms of pirenzepine impaired acquisition of the spatial aspects of the task, treated animals still appeared to be able to acquire a taxon strategy. A low dose of pirenzepine (10 micrograms) produced a slight deficit but this was only visible in a "spatial probe" trial. Although these results are consistent with the belief that muscarinic M1-receptors are involved in spatial learning, it cannot be excluded that the effects recorded were mediated by muscarinic M2-receptors, due to the low selectivity of pirenzepine.

An electrophysiological study of the projections of motor neurones that mediate non-cholinergic excitation in the circular muscle of the guinea-pig small intestine

The projections of neurones that produce the fast non-cholinergic excitatory junction potentials (e.j.p.s) in the circular muscle were analysed in the isolated ileum of the guinea-pig. Standard intracellular microelectrode techniques were used to record the amplitudes of such e.j.p.s in response to short trains of stimuli from transmural electrodes. Projections of the neurones around the circumference of the intestine were determined by plotting the change in e.j.p. amplitude with distance from longitudinally placed electrodes. Projections in the oral and anal directions were examined by recording at varying distances from transversely placed electrodes, and also by recording responses elicited close to longitudinal electrodes at various distances from lesions made 3–5 days earlier to interrupt orally and anally directed pathways. Experiments were performed in the presence of hexamethonium to determine the projections of the final motor neurones and in the absence of the drug to examine the projections of excitatory inputs to these neurones. With hexamethonium present, there was a decline in e.j.p. amplitude to 7.5% of maximum at 12 mm (a half circumference) from longitudinal stimulating electrodes. The decline was much less if hexamethonium was not present, and slightly greater if the myenteric plexus was removed. Thus, excitatory motor neurones and cholinergic neurones that impinge upon them both project circumferentially. When the longitudinal muscle and myenteric plexus were removed, and 3–5 days allowed for terminals to degenerate, no e.j.p.s could be recorded in the circular muscle, indicating that the fibres reach the circular muscle from the myenteric plexus. Following transverse lesions, substantial deficits in excitatory transmission only occurred within 1 mm oral or anal to the lesions indicating that the majority of neurones have only short projections along the intestine. A slight deficit in e.j.p. amplitude, up to 20%, was observed extending to about 5 mm oral; but normal transmission was restored by about 10 mm for the lesions. Thus there is a minority of excitatory motor neurones with oral projections up to about 10 mm in length. Results with transmural stimulation showed that these nerve fibres can cause excitation both when orthodromically and when antidromically stimulated, indicating that they provide collaterals along their lengths. With no hexamethonium present, e.j.p.s exhibited little decrement in amplitude over distances of over 30 mm oral or anal indicating that there are both ascending and descending cholinergic pathways that impinge on the final motor neurones. The projections determined by these physiological studies are consistent with previous anatomical and immunohistochemical studies of projections to the circular muscle of the guinea-pig small intestine.

The supernumerary segment systems of Rumex acetosa

The dioecious flowering plant Rumex acetosa is polymorphic for heterochromatic supernumerary segments carried on the short arms of chromosomes 1 and 6 in British populations. SS1 is found in the majority of populations but at a very low frequency, averaging only 4 per cent of chromosome 1. There is no obvious pattern to this distribution. SS6 was found in half the populations examined, all from the warmer southern and western parts of Britain. Overall it accounts for 6 per cent of chromosome 6 and averages 12 per cent in polymorphic populations. In heterozygotes SS1 is transmitted through the egg at a frequency of 0·63, a highly significant deviation from expectation. Pollen transmission shows a slight but nonsignificant deficit of SS1 chromosomes. Mendelian expectations were fulfilled for seven crosses involving SS6. One cross, however, showed a highly significant excess transmission through the pollen. It is argued that meiotic drive plays a role in the maintenance of the ubiquitous SS1 low-frequency polymorphism but not the SS6 polymorphism which shows clear environmental correlations.

Exploratory behavior and reaction to novelty in rats with hippocampal perforant path systems disrupted.

In this article, exploratory behavior and reaction to novelty were investigated in rats with either disruption of the total hippocampal perforant path projection (TPP), the medial perforant path (MPP), or lateral perforant path (LPP). All three experimental groups displayed increased locomotor activity, and the LPP group was even more active than the TPP and MPP groups. The TPP and LPP animals made more rearings than the control rats. The MPP and LPP groups exhibited less exploration of familiar objects than the TPP and control groups. TPP animals appeared unable to recognize novelty, LPP rats showed decreased preference for novelty, and MPP rats had only a slight deficit in recognition of novelty. It is suggested that perforant path disruptions reduce the hippocampal formation's access to sensory information of neocortical origin.

Anticonvulsant profile of flunarizine

AbstractThe purpose of the study was to examine in a multi‐experimental profile the purported similarity between the anticonvulsant effects of flunarizine, diphenylhydantoin, and carbamazepine. The compounds were injected at different time intervals and by different routes, and their effects were examined in a genetic model of epilepsy (audiogenic seizures in mice), against maximal seizures induced by bicuculline in mice and rats and in a seizurethreshold test (bicuculline infusion) in rats. All three compounds primarily affected tonic seizures. In the bicuculline seizure test, this was an all‐or‐none effect. In this test, flunarizine differed from diphenylhydantoin and carbamazepine in that it increased the threshold for clonic‐hindpaw seizures. Thus, flunarizine, apart from antagonizing tonic seizures, also increased the threshold for generalization. Further, in agreement with previous experiments (maximal metrazol test and kindling), the duration of action of flunarizine is longer than that of diphenylhydantoin and carbamazepine. Finally, the degree of ataxia and neurological deficits caused by a high p.o. dosis of flunarizine was assessed. A slight neurological deficit and ataxia occurred 1 hr after p.o. administration of 160 mg/kg of flunarizine. By way of analogy with diphenylhydantoin, as a working hypothesis, it is suggested that the anticonvulsant actions of flunarizine result from reducing Na+ currents in neurons, although a direct effect on Ca2+ movements cannot be excluded.

CELLULAR LOCATION AND PROPERTIES OF INVERTASE IN MYCELIUM OF PUCCINIA GRAMINIS

SummaryThe sucrose‐hydrolyzing activity in mycelium of the wheat stem rust fungus (Puccinia graminis Pers. f.sp. tritici Erikss. & E. Henn.) grown in axenic culture was compared with that in mycelium of Penicillium expansum (Linkex F. S. Gray). In subcellular fractions and permeabilized cells from Pu. graminis, most activity was bound tightly to the cell wall, whereas, in Pe. expansum, the enzyme was soluble and appeared to be located in the periplasmic space. Particulate preparations from mycelium of Pu. graminis hydrolyzed sucrose to a mixture of hexoses with a fructose: glucose ratio of about 0.8; hence the activity was essentially that of an ‘invertase’ (E.C. 3.2.1. 26, β‐D‐fructofuranoside fructohydrolase). Despite this slight deficit in fructose, no direct evidence was obtained for fructan transferase activity. By contrast, the enzyme preparation from Pe. expansum exhibited more transferase than hydrolase activity. The wall‐bound enzyme from Pu. graminis showed a pH optimum of 5.0 to 5.5, and Km values at pH 5. of 3 and 40 mM for sucrose and raffinose, respectively. All attempts to solubilize substantially the wall‐bound activity were unsuccessful, even after removal of 63% of the particulate matter by polysaccharide‐degrading enzymes.

Intra-operative awakening to monitor spinal cord function during scoliosis surgery. Description of the technique and report of four cases

We used a modification of the wake-up test to monitor spinal cord function in 102 consecutive scoliotic patients undergoing Harrington instrumentation. Four patients were found to have a neural deficit when they were awakened during the operation. Three recovered immediately after partial release of the distracting force; one required immediate removal of the rod and was left with a slight neural deficit. Using our method, we have encountered no problem in performing the wake-up test, although attention is drawn to the difficulty in repeating the test if the patient is re-anaesthetised with diazepam. There were no false negative results in this series.

Mirror Writing with Left Thalamic Hemorrhage

Three cases of mirror writing ( MW) with left thalamic hemorrhage were reported. All were right handed and the MW was limited to the left hand. All showed slight deficit in short term memory and in calculation. But none showed constructional difficulty or unilateral spatial neglect. Only one of them was considered as aphasic. MW was seen in voluntary writing and on dictation. Eye closure facilitated the tendency for MW. Also, it became more prominent when they had to write laterally from right to left than from left to right or in vertical direction. Automatic writing also facilitated the tendency while attention tended to suppress it. This tendency for MW seemed to fluctuate according to the level level of attention. As for the mechanism of MW in three cases, we discussed a possible role of the left thalamus. MW in the left hand can be seen in normal person under certain conditions. Therefore the MW seen in these cases may simply be a disclosure of the normal latent tendency. Lesions in the left thalamus may have contributed to the appearance of the MW by disturbing the attentional mechanism.

EINE EINFACHE SYNTHESE FÜR ISOMERENREINE 1-CHLOR-1-OXO-PHOSPHOL-3-ENE

Abstract Although the synthesis of 1-Chloro-1-oxo-phospholenes by (1 + 4)-cycloaddition of various trivalent Phosphorus compounds with at least one Phosphorus-Chlorine bond to 1,3-dienes has been investigated by different authors before, the influence of the reaction parameters, especially the molar ratios of the educts, has not been recognized in its importance toward the ratio of 2-and 3-Isomeres and the yield of the resulting 1-Chlor-1-oxo-phospholenes. From all described varieties, the reaction between Phosphorus-(III)chloride, Ethylenoxide and Buta-1,3-dien has proved to be the method of choice for a technical scale synthesis of 1-Chloro-1-oxo-phosphol-3-en. This paper reports the surprising effect of using nonstoichiometric amounts of Ethylenoxide, which leads to isomeric pure 1-Chloro-1-oxo-phosphol-3-en or to mainly 1-Chloro-1-oxo-phosphol-2-en when used in slight excess or deficit, respectively, thus offering a simple and convenient method for preparing definitive mixtures of both isomers in exce...

Theory of vacancy-controlled grain boundary motion

The effect of vacancy production/annihilation within a grain boundary (GB) as well as that of vacancy diffusion on grain boundary motion (GBM) has been theoretically considered. A formalism based on a discrete description of the diffusion process has been developed. The treatment permits a self-consistent calculation of both the rate of GBM and the vacancy concentration profile around the moving GB. Two complementary models of GBM have been analyzed in the framework of this treatment in a unified way: grain boundary displacement by direct atomic jumps across the GB and GBM resulting from vacancy production/annihilation within the boundary. While in the former case vacancies play a secondary role of ‘extrinsic’ defects affecting GBM only through their elastic or Coulomb interaction with the GB [mechanism (a)] or through an increased atomic jump rate in proximity to a vacancy [mechanism (a′)], the very occurrence of GBM in the latter case [mechanism (b)] is inherently associated with the operation of vacancy sinks/sources, the rate of GBM thus being governed by the vacancy kinetics. GB mobility as well as the vacancy concentration left behind a moving GB as predicted by the competing models have been analyzed. Qualitative differences of these predictions (vacancy enrichment for mechanisms (a) and (a′) vs a slight vacancy deficit for mechanism (b): different shapes of the mobility curves) provide a basis for an experimental identification of the operative mechanism of GBM. The existing theories of the effect of vacancies on GBM have been critically considered.

Electrical charge transfer between localized states in insulating thin films

D.c. measurements were used to study the electrical conductivity of FeF 3 and NiF 2 thin films. It is shown that for both compounds the conductivity arises from electronic transfer between localized states which correspond to a slight deficit of fluorine. These states are situated in the band gap at 1.1 eV and 1.75 eV below the conduction energy for FeF 3 and NiF 2 respectively. For NiF 2 the potential barriers between two adjacent sites are so great that only hopping is observed for the temperature range investigated (100–400 K). In contrast, for FeF 3, if a hopping mechanism again predominates at low temperatures, between 250 and 500 K the electrons jump over several potential barriers between the states. The experimentaL results agree well with the Poole model.