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Biomedical subjects

C J Wallace

Publications and source records attributed to C J Wallace.

141 records · Page 8Linked to original sources
PubMedDate not supplied

A strategy for development of computerized critical care decision support systems.

It is not enough to merely manage medical information. It is difficult to justify the cost of hospital information systems (HIS) or intensive care unit (ICU) patient data management systems (PDMS) on this basis alone. The real benefit of an integrated HIS or PDMS is in decision support. Although there are a variety of HIS and ICU PDMS systems available there are few that provide ICU decision support. The HELP system at the LDS Hospital is an example of a HIS which provides decision support on many different levels. In the ICU there are decision support tools for antibiotic therapy, nutritional management, and management of mechanical ventilation. Computer protocols for the management of mechanical ventilation (respiratory evaluation, ventilation, oxygenation, weaning and extubation) in patients with adult respiratory distress syndrome ((ARDS) have already been developed and clinically validated at the LDS Hospital. These protocols utilize the bedside intensive care unit (ICU) computer terminal to prompt the clinical care team with therapeutic and diagnostic suggestions. The protocols (in paper flow diagram and computerized form) have been used for over 40,000 hours in more than 125 adult respiratory distress syndrome (ARDS) patients. The protocols controlled care for 94% of the time. The remainder of the time patient care was not protocol controlled was a result of the patient being in states not covered by current protocol logic (e.g. hemodynamic instability, or transport for X-Ray studies). 52 of these ARDS patients met extra corporal membrane oxygenation (ECMO) criteria. The survival of the ECMO criteria ARDS patients was 41%, four times that expected (9%) from historical data (p less than 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude of Health Personnel↗
PubMedDate not supplied

Performance of computerized protocols for the management of arterial oxygenation in an intensive care unit.

Computerized protocols were created to direct the management of arterial oxygenation in critically ill ICU patients and have now been applied routinely, 24 hours a day, in the care of 80 such patients. The protocols used routine clinical information to generate specific instructions for therapy. We evaluated 21,347 instructions by measuring how many were correct and how often they were followed by the clinical staff. Instructions were followed 63.9% of the time in the first 8 patients and 92.3% in the subsequent 72 patients. Instruction accuracy improved after the initial 8 patients, increasing from 71.5% of total instructions to 92.8%. Instruction inaccuracy was primarily caused by software errors and inaccurate and untimely entry of clinical data into the computer. Software errors decreased from 7.2% in the first 8 patients to 0.8% in subsequent patients, while data entry problems decreased from 7.5% to 4.2%. We also assessed compliance with the protocols in a subset of 12 patients (2637 instructions) as a function of 1) the mode of ventilatory support, 2) whether the instruction was to increase or decrease the intensity of therapy or to wait for an interval of time and 3) whether the instruction was 'correct' or 'incorrect'. The mode of ventilatory support did not affect compliance with protocol instructions. Instructions to wait were more likely to be followed than instructions to change therapy. Ninety-seven percent of the correct instructions were followed and 27% of the incorrect instructions were followed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Gas Analysis↗
PubMedDate not supplied

cDNA and deduced amino acid sequences of cytochrome c from Chlamydomonas reinhardtii: unexpected functional and phylogenetic implications.

We have isolated complementary DNA (cDNA) clones for apocytochrome c from the green alga Chlamydomonas reinhardtii and shown that they are encoded by a single nuclear gene termed cyc. Cyc mRNA levels are found to depend primarily on the presence of acetate as a reduced carbon source in the culture medium. The deduced amino acid sequence shows that, apart from the probable removal of the initiating methionine, C. reinhardtii apocytochrome c is synthesized in its mature form. Its structure is generally similar to that of cytochromes c from higher plants. Several punctual deviations from the general pattern of cytochrome c sequences that is found in other organisms have interesting structural and functional implications. These include, in particular, valines 19 and 39, asparagine 78, and alanine 83. A phylogenetic tree was constructed by the matrix method from cytochrome c data for a representative range of species. The results suggest that C. reinhardtii diverged from higher plants approximately 700-750 million years ago; they also are not easy to reconcile with the current attribution of Chlamydomonas reinhardtii and Enteromorpha intestinalis to a unique phylum, because these two species probably diverged from one another at about the same time as they diverged from the line leading to higher plants.

Amino Acid Sequence↗
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Schizophrenic individuals' cognitive functioning and performance in interpersonal interactions and skills training procedures.

The purpose of this research was to determine the relationship between schizophrenic individuals' cognitive functioning and their performance in interpersonal interactions and skills training procedures. Thirty schizophrenic individuals and 15 non-mentally ill individuals were administered two versions of the Continuous Performance Test, the Span of Apprehension Test, the Digit Span Distractibility Test, the Assessment of Interpersonal Problem Solving Skills, and three elemental skills training tasks. Vigilance level as measured by the Continuous Performance Test was substantially correlated with performance in both roleplayed interactions and skills training tasks, while recall memory as measured by the Digit Span Distractibility Test was correlated with performance in the skills training tasks independently of vigilance level. Thus, the results indicated that the cognitive dysfunctions of schizophrenia are associated with poorer social functioning and with reduced performance in the elemental procedures that constitute efforts to improve that functioning.

Activities of Daily Living↗
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A training procedure for remediating WCST deficits in chronic psychotic patients: an adaptation of errorless learning principles.

Although a number of studies have demonstrated that psychiatric patients' performance deficits on the Wisconsin Card Sorting Test (WCST) can be modified through intervention, relatively little evidence exists to support the long-term durability of training effects. The present study tested the effectiveness and durability of a training procedure based on errorless learning principles, and in addition sought to determine the effect of previously committed errors on training and post-training performance. Twenty-three chronic psychotic inpatients were randomly assigned to an Initial Error (n = 11) or No Initial Error (n = 12) group. The Initial Error group received two standard administrations of the WCST prior to training (where they were expected to commit many errors); the No Initial Error group had no prior exposure to the WCST. All subjects received training on the WCST which was followed by immediate, 1-, 2-, and 4-week post-tests. Results supported the effectiveness of training and the durability of effects, but previous error history showed no clear relationship to post-training performance.

Adolescent↗
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Improving social interaction in chronic psychotic using discriminated avoidance ("nagging"): experimental analysis and generalization.

Three social-interaction behaviors of a withdrawn chronic schizophrenic were increased using a discriminated avoidance ("nagging") procedure. The three behaviors were: (a) voice volume loud enough so that two-thirds of his speech was intellibible at a distance of 3m; (b) duration of speech of at least 15 sec; (c) placement of hands and elbows on the armrests of the chair in which he was sitting. "Nagging" consisted of verbal prompts to improve performance when the behaviors did not meet their criteria. A combined withdrawal and multiple-baseline design was used to evaluate the effectiveness of the procedure, and the contingency was sequentially applied to each of the three behaviors in each of four different interactions to determine the degree of stimulus and response generalization. Results indicated that the contingency was the effective element in increasing the patient's appropriate performance, and that there was a high degree of stimulus generalization and a moderate degree of response generalization. After the patient's discharge from the hospital, the durability of improvement across time and setting was determined in followup sessions conducted at a day treatment center and at a residential care home. Volume and duration generalized well to the new settings, while arm placement extinguished immediately.

Adult↗
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MR imaging of a hemorrhagic and granulomatous cyst of the ligamentum flavum with pathologic correlation.

Cysts of the ligamentum flavum are uncommon causes of neurologic signs and symptoms and usually are seen in persons over 50 years of age. We report a case of an epidural cyst located in the ligamentum flavum, which contributed to spinal stenosis in a 30-year-old man. Radiologic features were similar to those of a synovial cyst, but synovium was not identified histologically. The imaging and pathologic features were unusual, including hemorrhage and a fibrohistiocytic reaction with giant cells.

Adult↗
PubMedDate not supplied

Protein engineering of cytochrome c by semisynthesis: substitutions at glutamic acid 66.

We have used protein semisynthesis to prepare four analogues of horse cytochrome c, in which the glutamic acid residue at position 66 has been removed and replaced by norvaline, glutamine, lysine and, as a methodological control, glutamic acid. This residue is quite strongly conserved in mitochondrial cytochrome c, and forms part of a cluster of acidic residues that occurs in all cytochromes c but whose function is obscure. Comparative studies of the physical and biochemical properties of the analogues have now disclosed two specific roles for Glu66 in the protein. It contributes significantly to the stabilization of the active conformation of the protein, probably by salt bridge formation, and it appears to participate in the redox-state-dependent ATP-binding site of cytochrome c. Our results also support two general views of the role of surface charged residues in cytochrome c, namely that their disposition influences both redox potential, through the electrostatic field felt at the redox centre, and the kinetics of electron transfer, through the dipole moment they generate.

Amino Acid Sequence↗
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Lymph node metastases from glioblastoma multiforme.

Extraneural metastases from glioblastoma multiforme are rare. Spread to the extracranial head and neck may be evident on routine follow-up images of the original lesion. We present two cases, one with documented metastatic adenopathy in the head and neck from glioblastoma and the other with probable metastatic disease in a lymph node in which biopsy was not performed, and discuss probable mechanisms of extraneural extension of this tumor.

Adult↗