Biomedical subjects
S W Brown
Publications and source records attributed to S W Brown.
Fatal liver failure following generalized tonic-clonic seizures.
We present three cases of fatal hepatic necrosis in patients with epilepsy taking anticonvulsants, in which the terminal illness presented as an unusually severe generalized tonic-clonic seizure with failure to regain consciousness. In two cases acute renal failure also occurred. It is not certain to what extent drug therapy, physiological and metabolic changes consequent on prolonged seizures, hitherto undiscovered infective agents, or a combination of any of these may play in such a process. We suggest, however, that the case against the drugs alone has yet to be proved.
Non-epileptic seizures: management and predictive factors of outcome.
We report a prospective series of 18 patients with a diagnosis of non-epileptic seizures (NES, pseudoseizures) identified in one unit. Sixteen patients agreed to complete a therapeutic programme. At the end of treatment eight were seizure free, three had only occasional NES and five were unchanged. At 1-year follow-up the situation remained similar regarding seizures, with responders demonstrating an improvement in social functioning and a marked reduction in demands on health service resources. Admission variables significantly associated with a poor outcome were an IQ of less than 80 and a past history of violent behaviour.
Some issues in the assessment of epilepsy occurring in the context of learning disability in adults.
Epilepsy is a common condition in people with learning difficulties. The assessment of seizure disorders in this group requires special consideration of psychological and social, as well as medical, aspects. We consider an integrated approach assessing epilepsy and learning difficulties in parallel. Such meticulous assessment can lead to improved quality of life with treatment changes, and will avoid unnecessary medical and social costs.
Attention and interference in prospective and retrospective timing.
Subjects listened to a series of musical selections and then judged the duration of each selection. Some subjects were informed beforehand that timing was involved (prospective timing) whereas others were informed afterwards (retrospective timing). Half the groups performed a concurrent proofreading task during stimulus presentation. The results showed a trade-off between temporal and nontemporal task performance: prospective-timing groups were more accurate in judging time and were worse at proofreading, whereas retrospective-timing groups were relatively poor at judging time but better at proofreading. This pattern is consistent with Michon's notion of an essential equivalence between temporal and nontemporal processing, and supports the predictions of an attentional allocation model of timing. The proofreading task interfered both with prospective and with retrospective timing, and both types of time judgments were influenced in the same way by effects of stimulus context. These results imply that similar timing processes operate under prospective and retrospective conditions.
Capitation from a provider's perspective.
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Aerobic exercise in the psychological treatment of adolescents.
A small group of psychiatrically institutionalized adolescents (16 boys, 11 girls) were assigned to a three-day-per-week running/aerobic exercise program or a regular physical activity class. The complete program continued over 9 weeks, with 11 subjects remaining throughout the program. Dependent measures of body-mass index, timed performance on a one-mile run, resting, exercise, and recovery heart rates, and measures of depression, mood-states, and self-efficacy were assessed pre-, mid-, and post-9-wk. treatment and at a 4-wk. follow-up. Improvements in depression, anxiety, hostility, confused thinking, and fatigue were shown in treated girls, with increases in vigor and self-efficacy for all treated subjects.
Purification and biochemical characterization of recombinant alpha 1-antitrypsin variants expressed in Escherichia coli.
Site-directed variants of alpha 1-antitrypsin (alpha 1AT) expressed in a recombinant strain of Escherichia coli have been isolated with an overall process yield of 50% following tangential flow ultrafiltration, anion-exchange, immobilized metal affinity, and hydrophobic interaction chromatography. The primary structure of the purified variants including the integrity of the N- and C-termini has been verified by electrospray mass spectrometry of the intact molecules (44 kDa) for two of the variants (alpha 1AT Leu-358 and alpha 1AT Ala-357, Arg-358). Complementary classical peptide mapping and automated amino acid sequencing have verified 75% of the primary sequence of alpha 1AT Ala-357, Arg-358. Isoelectric focusing in an immobilized pH gradient revealed some microheterogeneity which proved to be reproducible from one purification batch to another. The isolated variants of alpha 1AT did not show any signs of proteolytic degradation during the purification process and proved to be fully active against their target proteases. The described process also allowed the complete removal of endotoxins from the preparations, opening the possibility to evaluate these novel protease inhibitors for their in vivo efficacy in different animal models of human disease.
The production of biotin by recombinant strains of Escherichia coli.
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Methodology for evaluating the Monroe-Livingston capitation system.
This paper presents the methodology for evaluating the Monroe-Livingston demonstration project's capitation payment system (CPS), based in Rochester, New York, for chronic mentally ill patients. To allow for both patient and provider choice within the experimental design, 1,587 CPS-eligible patients were randomly assigned at the start of the study to control or experimental conditions, with the intent of capturing in the experimental group a significant number of patients who would later be enrolled in the CPS. Protocols, which included measures of symptomatology, functioning, and resource utilization, were completed at baseline for 422 of the 605 patients contacted for inclusion in the study. The baseline control group included 143 patients; the experimental group included 279 patients, 153 of whom were eventually enrolled in the CPS.
Factor analysis of responses to the WISC-R for gifted children.
Several researchers have focused on the question of whether the traditional two-factor interpretation of WISC--R scores proposed by Wechsler (1974) is appropriate in selecting students to be admitted to gifted programs. Some researchers have suggested that the two-factor solution (Verbal and Performance) of Karnes and K. E. Brown provides the appropriate model, while others have proposed an alternative model based on exploratory research with gifted and average students. The current study expands exploratory findings of S. W. Brown with Rood in 1982 and Yakimowski in 1987, using confirmatory factor analytical procedures. The confirmatory factor analyses for selected groups of gifted (n = 158) and average (n = 195) students (M = 9.6 yr.) indicate that the alternative three-factor solution model may be a better system for interpreting the pattern of WISC--R subtest scores of gifted students than the conventional Verbal and Performance solution.
The production of biotin by genetically modified micro-organisms.
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Traumatic chylothorax: a case report.
A case of traumatic chylothorax following a motor vehicle accident is presented. This is a rare injury following thoracic trauma and is associated with a high mortality and morbidity. Mechanisms of injury to the thoracic duct are described. A management strategy is suggested, which initially entails a trial of conservative therapy of adequate drainage, total parenteral nutrition (TPN) and total gut rest. If significant chyle losses persist after 2 weeks, surgery is indicated, as immunological factors may complicate recovery. The recommended surgical technique is transthoracic duct ligation directly or at the hiatus.
Sudden death and epilepsy.
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Multiple timing and the allocation of attention.
Two experiments were designed to examine the effects of multiple timing tasks on prospective time judgment performance. In experiment 1, subjects were required to monitor the durations of one, two, three, or four concurrent target stimuli which began and ended at different times, and then reproduce one of those durations subsequently chosen at random. Time judgment accuracy deteriorated as the number of target stimuli increased. In experiment 2, subjects used the production method to generate specified durations for one, two, three, or four partially overlapping stimuli. Timing was less accurate in conditions involving more target stimuli. In the multiple-target conditions, time judgments were less accurate for the later- rather than earlier-onset targets. The results support an attentional model of timing, and suggest that timing is an effortful process which draws from limited attentional resources.
Separation of conjoined twins.
The incidence of conjoined twins is rare, occurring in one in 50-80,000 live births. The rarity of the occurrence presents quite a management challenge. The first case in New Zealand of successfully separated thoraco-omphalagus twins, presenting top-to-tail, is described.
Regulation of Bacillus subtilis glutamine synthetase gene expression by the product of the glnR gene.
Transcription of the Bacillus subtilis gene coding of glutamine synthetase (glnA) is regulated by the nitrogen source. The glnA gene lies in an operon in which it is preceded by an open reading frame with the potential to encode a polypeptide of approximately 16,000 Mr. We have now shown that this open reading frame is utilized in vivo, that its product (GlnR) acts as a diffusible, negative regulator of gln transcription, and that GlnR is likely to be a DNA-binding protein. Certain mutations in glnR, including a large, in-frame deletion and a start codon mutation, led to high-level constitutivity of the operon; other mutations caused low-level constitutivity. These latter mutations, which affected the C terminus of GlnR, seemed to disrupt response to the nitrogen source without eliminating the ability of GlnR to bind to DNA. Wild-type GlnR by itself, however, did not impose nitrogen-dependent regulation; such regulation also required the product of glnA. A model is presented in which glutamine synthetase monitors the availability of nitrogen and imposes negative regulation by interaction with or modification of GlnR.
Isolation of recombinant partial gag gene product p18 (HIV-1Bru) from Escherichia coli.
The membrane-associated structural protein, p18, of the human immunodeficiency virus (HIV-1), has been expressed in Escherichia coli. The recombinant protein was purified by cation-exchange chromatography on S Sepharose followed by cation-exchange high-performance liquid chromatography (HPLC) on Sulfoethyl Aspartamide. The isolation of 28.7 mg of recombinant p18 from 16.71 of cell culture represents an overall yield of ca. 20%. Recombinant p18 was characterized by sodium dodecyl sulphate polyacrylamide gel electrophoresis, reversed-phase HPLC, amino acid composition and amino acid sequence analysis of the N-terminus. Edman degradation of peptides generated by trypsin or Staphylococcus aureus V8 proteolytic digestion, including the C-terminus, confirmed the amino acid sequence to be that predicted from the cDNA. A C-terminally cleaved form of recombinant p18, p18LM, was separated in the cation-exchange HPLC step and was partially characterized in parallel with the intact molecule. By Western blotting it was shown that recombinant p18 in addition to the cleaved form p18LM is recognized by a monoclonal antibody which was generated against the natural protein from HIV-1.