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Biomedical subjects

E A Sanders

Publications and source records attributed to E A Sanders.

At least 19 recordsLinked to original sources

[Good results in reoperation of recurrent radicular syndrome following surgery for herniated nucleus pulposus].

In the period 1985-1986 twenty-four patients with a recurrent lumbar disk herniation were subjected to surgery in the department of Neurosurgery in the Academic Medical Hospital of Utrecht. In 25% of these patients the second lumbar disk herniation was at the same level and side as the first one. Recurrence of the disk rupture at the same side and level as the first one occurred most often within two years after initial surgery. A recurrent slipped disk at different lumbar level occurred after a time interval of two years or more. Correct diagnosis depends on the results of imaging techniques. All reoperated patients did well after surgery and could return to their work or normal daily obligations.

Adolescent

Psychiatric symptoms and mental changes as major features of multiple sclerosis.

A patient is presented with clinically and laboratory supported definite multiple sclerosis who developed severe depression followed by mental deterioration. Magnetic resonance imaging MRI demonstrated multiple hemispherical lesions. It is suggested that the psychiatric and cognitive signs and symptoms observed in this patient are due to severe cerebral demyelination.

Adult

[Multiple sclerosis in childhood].

A 15-year-old girl presented with signs and symptoms indicative for multiple sclerosis. A final diagnosis could only be reached after 9 years follow up and with help of the MRI technique. The differential diagnosis of multiple sclerosis at a young age is discussed.

Adolescent

Studies on the production of lipase from recombinant Staphylococcus carnosus.

Production of lipase from recombinant Staphylococcus carnosus pLipPS1 was studied in standard stirred tank bioreactors. Only low lipase activity was obtained under conventional operating conditions, i.e., moderate to high stirring speeds and aeration rates for keeping the dissolved oxygen concentration at high levels. Additional targetted experiments indicated that the reason for the observed low lipase activity is lipase inactivation due to surface forces and shear stress at the gas/liquid interface. Therefore, a cultivation strategy is proposed that minimizes gas/liquid interfacial area and maximizes the driving concentration for O2 mass transfer by controlling the dissolved oxygen to low values by gentle stirring and low aeration rates. Thus, high lipase activities can be obtained even in larger scale standard stirred tank bioreactors.

Fermentation

High cell density cultivation of Escherichia coli at controlled specific growth rate.

A high cell density cultivation (HCDC) for growth of Escherichia coli in an especially designed glucose/mineral salt medium is proposed. The HCDC essentially starts as a batch process which is followed by a two-phase fed-batch cultivation. After unlimited growth at mu max = 0.45 h-1 in the batch part, growth was controlled at a reduced specific growth rate (mu = 0.11 h-1 less than mu max) over a period of 3 doubling times in which the biomass concentration increased from 12 to 95 g 1(-1) (phase 1 of fed-batch cultivation). Control of growth (mu) was realized by a PO2 control loop (by variation of glucose feeding) and a mu control loop (by variation of agitation speed N) while the actual mu was calculated from the off-gas composition. If the agitation rate cannot be increased anymore the mu controller is switched off (end of phase 1). In the following phase 2, mu declines, however, the still acting pO2 (glucose) controller guarantees sufficient O2 supply till the end of the cultivation with a biomass concentration of 110 g 1(-1) (dry mass). The proposed HCDC suppresses generation of inhibitory by-products and the high yield coefficients indicate the economy of the process.

Bacteriological Techniques

Action of sympathomimetic drugs on the bronchial circulation of the horse.

In the quietly standing horse I.V. administration of adrenaline decreased, and of dobutamine increased, bronchial artery flow. These changes paralleled changes in arterial pressure. With phenylephrine and noradrenaline bronchial artery flow decreased while arterial pressure increased, indicating active vasoconstriction in the bronchial circulation. With clenbuterol an increase in bronchial artery flow was accompanied by a decrease in systemic blood pressure, indicating bronchial arterial vasodilatation. We conclude that alpha-constrictor and beta 2-dilator receptors are present in the bronchial artery bed and that stimulation of these receptors could explain changes in flow seen in the horse during exercise and anaesthesia.

Animals

Anesthetic management for instrumentation of the pregnant rhesus monkey.

The anesthetic procedures used and the responses observed during maternal instrumentation on 38 pregnant rhesus monkeys (Macaca mulatta) during the second half of gestation are reported. A laparotomy with maternal instrumentation was performed in all animals. Anesthesia was induced with ketamine and maintained with halothane. Two animals delivered within five days of anesthesia and surgery and were unable to undergo experimentation. The remaining 36 animals underwent successful experimentation. Dysrhythmias, hypotension, and hypothermia were identified as complications of anesthesia.

Anesthesia, General

[Juvenile dermatomyositis, systemic lupus erythematosus and mixed connective tissue disease].

This paper covers the current insights into the classification, etiology, management and prognosis of juvenile dermatomyositis (JDMS) systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Since specific diagnostic tests for these autoimmune diseases are not available, diagnosis depends on the presence of defined criteria. Drug therapy in JDMS consists of prednisone at a low dosage (1 mg/kg/day). In SLE different therapeutic approaches are known depending on the occurrence of life threatening symptoms. The prognosis of MCTD is good, it is of prime importance to avoid overdosage of corticosteroids, since drug treatment is often not needed.

Adrenal Cortex Hormones

Memory and learning in outpatients with quiescent multiple sclerosis.

In 22 (56%) of 39 quiet-stage multiple sclerosis (MS) patients with at least average intelligence quotients, performances in memory and learning tasks were normal, as compared with those of a control group (24 healthy volunteers). Of the remaining 44% (n = 17), 2 patients were amnesic and 5 had been judged to have suffered cognitive decline. Auditory word learning was particularly vulnerable; however, acquisition rate was not significantly different between MS patients and controls.

Adolescent

Performances of multiple sclerosis patients in tasks requiring language and visuoconstruction. Assessment of outpatients in quiescent disease stages.

In a group of 39 multiple sclerosis (MS) patients with at least average intelligence quotients (IQ), performances were examined in tests requiring language usage and figure copying. Numbers of correct, digressive and erroneous responses were analysed and compared with those obtained in 24 healthy volunteers, matched to the patients group for socio-economic status. The examined specific tasks yielded no additional contribution to the prevalence estimation of cognitive deterioration (18%), as based on an assessment of general intelligence. Linguistic or cognitive-constructional problems were no more severe or more frequent in MS patients than those in control subjects. Upon writing or copying figures, pencil stroke and pencil pressure were deficient. Speed of reading aloud and of colour naming was decreased in the MS group, the most probable explanation being impaired control of the phonatory apparatus, oculomotor problems or weakness of colour vision. Decreases in speed of performance are not necessarily of cognitive origin. Differences between the present and previous reports based on similar tasks, appear to be connected partly with differences in patient selection. Of the present group, all MS patients were in quiescent disease stages, depression was mild or absent and physical handicap was less than in most studies reporting definite specific deficits.

Adult

Visuospatial problem solving, conceptual reasoning and sorting behaviour in multiple sclerosis out-patients.

Visuospatial problem solving, conceptual reasoning and shifting of set were studied in out-patients with definite and probable MS. The sample of MS patients was homogeneous with respect to 2 important dimensions. All were out-patients, leading a normal although handicap-restricted social life. Furthermore, in all patients relapse or obvious instability of the disease were absent for at least a month. On Raven's Progressive Matrices, the Category test and the Wisconsin Modified Card Sorting test, no significant differences were found between the group of MS patients and a control group of healthy volunteers. However, 18% of MS patients and 4% of controls were rated as performing slightly below the expected levels of cognition. Stepwise regression analysis failed to reveal effects of illness variables, and no difference between patients with definite and probable MS could be detected. Clearly, most socially integrated MS patients in stable disease stages are capable of normal visuospatial problem solving, abstract reasoning and shifting of set.

Adolescent

Reaction time in ambulant multiple sclerosis patients. Part I. Influence of prolonged cognitive effort.

Reaction times (RT) were measured in 39 multiple sclerosis (MS) patients and 25 healthy controls, before and after comprehensive neuropsychological assessment lasting at least 4 h. The assessment required prolonged mental effort, which was assumed to induce fatigue. Simple and disjunctive RT were measured for visual and auditory stimuli. RT before and after prolonged effort were significantly longer in MS than in control subjects (with exception of auditory RT). This effect was related to disease duration and to simultaneous presence of brainstem, cerebellar and/or pyramidal signs. Age did not significantly contribute to the explanation of RT increase. In female patients, increasing distribution of functional lesions in the central nervous system was related with greater RT increase than in male patients. RT of MS and controls changed after prolonged mental effort and effort-related fatigue was experienced subjectively. Yet no differences in direction or degree of change in RT were found between controls and ambulant patients with stable MS who apparently had resources to overcome fatigue.

Adolescent