Association of Health Literacy and Area Deprivation With Initiation and Completion of Telehealth Visits in Adult Medicine Clinics Across a Large Health Care System

This cross-sectional study assesses whether health literacy and area deprivation index are associated with completion rates of telehealth video visits among adult patients in a large health care system.

Relation of the Dietary Approaches to Stop Hypertension Dietary Pattern to Heart Failure Risk and Socioeconomic Status (from the Southern Community Cohort Study)

The Dietary Approaches to Stop Hypertension (DASH) dietary pattern has been associated with a lower risk of incident heart failure (HF); however, previous studies were conducted in mostly middle-income White populations. The association between DASH and incident HF risk in lower income and Black individuals is less well understood. We analyzed 25,300 White and Black adults without a history of HF at enrollment (2002 to 2009) in the Southern Community Cohort Study receiving Centers for Medicare and Medicaid Services. Alignment with DASH was assessed at enrollment using a validated food frequency questionnaire. Incident HF was ascertained from Centers for Medicare and Medicaid Services claims through 2016. The association between DASH diet alignment and incident HF was examined in multivariable-adjusted Cox proportional hazards regression models, including an interaction term testing effect modification by income. The cohort was predominantly middle-aged (median 54 years), Black (68%), female (63%), and low-income (88% <$25,000/year/household). Socioeconomic factors, including education and annual income, were larger contributors to the variance in DASH score than were cardiovascular co-morbidities. The association between DASH dietary alignment and HF risk was not significant overall (hazard ratio [HR] 1.00; 95% confidence interval [CI] 0.96 to 1.04) or in race-sex groups. However, the association between alignment with the DASH diet and HF risk significantly varied by income (interaction p = 0.030), with neutral and inverse associations in lower (<$25,000/year) and higher ($≥25,000) income participants, respectively. In conclusion, income modified the association between healthier dietary patterns and risk of incident HF. In lower income participants, greater alignment with the DASH diet was not associated with lower HF risk.

Herpes simplex virus-infected squamous cell carcinoma: a case report

BACKGROUND

Herpes simplex virus (HSV)-1 is a highly prevalent, non-oncogenic virus that has higher morbidity in immunocompromised hosts. Its most common clinical manifestation is superficial ulceration of the integument or mucus membranes.

CASE PRESENTATION

A 65-year-old woman with a history of acute myelogenous leukemia treated with allogenic peripheral blood stem cell transplant presented for resection of an ulcerated buccal squamous cell carcinoma. We report a case of HSV-1-infected malignant cells discovered on histopathological examination of the carcinoma specimen ultimately treated with valacyclovir.

CONCLUSIONS

HSV-1 is not considered an oncogenic virus itself but may increase risk of malignant progression. Cancer cells are vulnerable to superimposed viral infections, including HSV-1, which likely led to the findings in this case.

Reversible, regional ST-segment elevation due to chylothorax

Chylothorax is an uncommon complication of thoracic surgery and, to our knowledge, has never been documented as a cause of dynamic ST-segment elevation (STE). A 63-year-old woman with history of right pneumonectomy presented with chest pain and regional STE on 12-lead electrocardiogram (ECG). Normal troponin-I and a computed tomography (CT) scan showing a large right hemithoracic fluid collection indicated the unique cause of STE, which resolved after thoracentesis, was pericardial inflammation and cardiac compression from chylothorax. This case emphasizes nuances of ECG interpretation in the context of regional STE and explores the pathophysiology that links chylothorax with acute pericarditis.

Mouse strain-dependent variation in obesity and glucose homeostasis in response to high-fat feeding

AIMS/HYPOTHESIS

Metabolic disorders are commonly investigated using knockout and transgenic mouse models. A variety of mouse strains have been used for this purpose. However, mouse strains can differ in their inherent propensities to develop metabolic disease, which may affect the experimental outcomes of metabolic studies. We have investigated strain-dependent differences in the susceptibility to diet-induced obesity and insulin resistance in five commonly used inbred mouse strains (C57BL/6J, 129X1/SvJ, BALB/c, DBA/2 and FVB/N).

METHODS

Mice were fed either a low-fat or a high-fat diet (HFD) for 8 weeks. Whole-body energy expenditure and body composition were then determined. Tissues were used to measure markers of mitochondrial metabolism, inflammation, oxidative stress and lipid accumulation.

RESULTS

BL6, 129X1, DBA/2 and FVB/N mice were all susceptible to varying degrees to HFD-induced obesity, glucose intolerance and insulin resistance, but BALB/c mice exhibited some protection from these detrimental effects. This protection could not be explained by differences in mitochondrial metabolism or oxidative stress in liver or muscle, or inflammation in adipose tissue. Interestingly, in contrast with the other strains, BALB/c mice did not accumulate excess lipid (triacylglycerols and diacylglycerols) in the liver; this is potentially related to lower fatty acid uptake rather than differences in lipogenesis or lipid oxidation.

CONCLUSIONS/INTERPRETATION

Collectively, our findings indicate that most mouse strains develop metabolic defects on an HFD. However, there are inherent differences between strains, and thus the genetic background needs to be considered carefully in metabolic studies.

A review of medication reconciliation issues and experiences with clinical staff and information systems

Medication reconciliation was developed to reduce medical mistakes and injuries through a process of creating and comparing a current medication list from independent patient information sources, and resolving discrepancies. The structure and clinician assignments of medication reconciliation varies between institutions, but usually includes physicians, nurses and pharmacists. The Joint Commission has recognized the value of medication reconciliation and mandated implementation in 2006; however, a variety of issues have prevented simple, easy, and universal implementation. This review references issues related to the development and the implementation of medication reconciliation including: - the need of a system or standard for accurate drug identification to create a definitive 'gold standard' patient medication list, - identifying stakeholders of medication reconciliation within the institution and contrasting staff interest and participation with institutional resources, - observations and opportunities of integrating medication reconciliation with the electronic patient health record, and - summarizing a series of institutions experiences developing and implementing medication reconciliation. Last, as medication reconciliation becomes a regular process within medical centers, key concepts for effective implementation are discussed.

Characterization of Amylolytic Enzymes, Having Both alpha-1,4 and alpha-1,6 Hydrolytic Activity, from the Thermophilic Archaea Pyrococcus furiosus and Thermococcus litoralis

Extracellular pullulanases were purified from cell-free culture supernatants of the marine thermophilic archaea Thermococcus litoralis (optimal growth temperature, 90 degrees C) and Pyrococcus furiosus (optimal growth temperature, 98 degrees C). The molecular mass of the T. litoralis enzyme was estimated at 119,000 Da by electrophoresis, while the P. furiosus enzyme exhibited a molecular mass of 110,000 Da under the same conditions. Both enzymes tested positive for bound sugar by the periodic acid-Schiff technique and are therefore glycoproteins. The thermoactivity and thermostability of both enzymes were enhanced in the presence of 5 mM Ca, and under these conditions, enzyme activity could be measured at temperatures of up to 130 to 140 degrees C. The addition of Ca also affected substrate binding, as evidenced by a decrease in K(m) for both enzymes when assayed in the presence of this metal. Each of these enzymes was able to hydrolyze, in addition to the alpha-1,6 linkages in pullulan, alpha-1,4 linkages in amylose and soluble starch. Neither enzyme possessed activity against maltohexaose or other smaller alpha-1,4-linked oligosaccharides. The enzymes from T. litoralis and P. furiosus appear to represent highly thermostable amylopullulanases, versions of which have been isolated from less-thermophilic organisms. The identification of these enzymes further defines the saccharide-metabolizing systems possessed by these two organisms.

Purification and characterization of a highly thermostable glucose isomerase produced by the extremely thermophilic eubacterium, Thermotoga maritima

Thermotoga maritima, among the most thermophilic eubacteria currently known, produces glucose isomerase when grow in the presence of xylose. The purified enzyme is a homotetramer with submit molecular Wight of about 45,000. It has a number of features in common with previously described glucose isomerases-pH optimum of 6.5 to 7.5, presence of active-site histidine, requirement for metal cations such as Co(2+) and Mg(2+), and preference for xylose as substrate. In addition, it has significant sequence/structural homology with other glucose isomerases, as shown by both N-terminal sequencing and immunological crossreactivity. The T. maritima enzyme is distinguished by its extreme thermostability-a temperature optimum of 105 to 110 degrees C, and an estimated half-life of 10 minutes at 120 degrees C, pH 7.0. The high degree of thermostability, coupled with a neutral to slightly acid pH optimum, reveal this enzyme to be a promising candidate for improvement of the industrial glucose isomerization process.

Differential effects of acute and repeat dosing with the H3 antagonist GSK189254 on the sleep-wake cycle and narcoleptic episodes in Ox-/- mice

BACKGROUND AND PURPOSE

Histamine H3 receptor antagonists are currently being evaluated in clinical trials for a number of central nervous system disorders including narcolepsy. These agents can increase wakefulness (W) in cats and rodents following acute administration, but their effects after repeat dosing have not been reported previously.

EXPERIMENTAL APPROACH

EEG and EMG recordings were used to investigate the effects of acute and repeat administration of the novel H3 antagonist GSK189254 on the sleep-wake cycle in wild-type (Ox+/+) and orexin knockout (Ox-/-) mice, the latter being genetically susceptible to narcoleptic episodes. In addition, we investigated H3 and H1 receptor expression in this model using radioligand binding and autoradiography.

KEY RESULTS

In Ox+/+ and Ox-/- mice, acute administration of GSK189254 (3 and 10 mg x kg(-1) p.o.) increased W and decreased slow wave and paradoxical sleep to a similar degree to modafinil (64 mg x kg(-1)), while it reduced narcoleptic episodes in Ox-/- mice. After twice daily dosing for 8 days, the effect of GSK189254 (10 mg x kg(-1)) on W in both Ox+/+ and Ox-/- mice was significantly reduced, while the effect on narcoleptic episodes in Ox-/- mice was significantly increased. Binding studies revealed no significant differences in H3 or H1 receptor expression between Ox+/+ and Ox-/- mice.

CONCLUSIONS AND IMPLICATIONS

These studies provide further evidence to support the potential use of H3 antagonists in the treatment of narcolepsy and excessive daytime sleepiness. Moreover, the differential effects observed on W and narcoleptic episodes following repeat dosing could have important implications in clinical studies.

Characterization of histamine H3 receptors in Alzheimer's Disease brain and amyloid over-expressing TASTPM mice

BACKGROUND AND PURPOSE

Histamine H3 receptor antagonists are currently being evaluated for their potential use in a number of central nervous system disorders including Alzheimer's Disease (AD). To date, little is known about the state of H3 receptors in AD.

EXPERIMENTAL APPROACH

In the present study we used the radiolabelled H3 receptor antagonist [3H]GSK189254 to investigate H3 receptor binding in the amyloid over-expressing double mutant APPswe x PSI.MI46V (TASTPM) transgenic mouse model of AD and in post-mortem human AD brain samples.

KEY RESULTS

No significant differences in specific H3 receptor binding were observed between wild type and TASTPM mice in the cortex, hippocampus or hypothalamus. Specific [3H]GSK189254 binding was detected in sections of human medial frontal cortex from AD brains of varying disease severity (Braak stages I-VI). With more quantitative analysis in a larger cohort, we observed that H3 receptor densities were not significantly different between AD and age-matched control brains in both frontal and temporal cortical regions. However, within the AD group, [3H]GSK189254 binding density in frontal cortex was higher in individuals with more severe dementia prior to death.

CONCLUSIONS AND IMPLICATIONS

The maintenance of H3 receptor integrity observed in the various stages of AD in this study is important, given the potential use of H3 antagonists as a novel therapeutic approach for the symptomatic treatment of AD.

Integrating pharmacokinetics knowledge into a drug ontology: as an extension to support pharmacogenomics

The newly developed U.S. Common Medication Information Infrastructure was used as a basis to capture and formally express the properties of drugs relevant to research and the clinical application of pharmacogenomics. Two associated taxonomies within the model, Mechanism of Action and Physiologic Effect, were enriched to accommodate pharmacogenomic use-cases; the 4,000 active ingredients in the VA NDF-RT drug file were related to the enhanced taxonomies. Pharmacokinetics were independently modeled for pharmacogenomics and tested against thirty-one high-profile drugs to demonstrate our approach.

Automated enhancement of description logic-defined terminologies to facilitate mapping to ICD9-CM

Compositional (post-coordinated) terminologies are one potential solution to the problem of content completeness. However, they have the potential to render data incomparable. For computers to determine that compositional expressions are comparable, the relations between the composed components that are understood implicitly by human readers must be represented explicitly for computer manipulation. We discuss a technique for discovering and formalizing the implicit semantic relationships in two vocabularies: the International Classification of Disease Version 9 Clinical Modification (ICD9-CM), and SNOMED-Reference Terminology (SNOMED-RT). The results of this technique are used to augment the existing SNOMED-RT relation ontology, which is a necessary step in automated concept mapping between systems. The reference terminology must contain all the semantics implicit in the classification in order to map concepts between the two representations. We also provide an explicit representation of the implied semantics of ICD9-CM. This tabulation will be useful for other knowledge engineering efforts involving ICD9-CM.

Guideline for health informatics: controlled health vocabularies--vocabulary structure and high-level indicators

Developers and purchasers of controlled health terminologies require valid mechanisms for comparing terminological systems. By Controlled Health Vocabularies we refer to terminologies and terminological systems designed to represent clinical data at a granularity consistent with the practice of today's healthcare delivery. Comprehensive criterion for the evaluation of such systems are lacking and the known criteria are inconsistently applied. Although there are many papers, which describe specific desirable features of a controlled health vocabulary, to date there is not a consistent guide for evaluators of terminologies to reference, which will help them compare implementations of terminological systems on an equal footing 1,2 This guideline serves to fill the gap between academic enumeration of desirable terminological characteristics and the practical implementation or rigorous evaluations which will yield comparable data regarding the quality of one or more controlled health vocabularies.

Development of a homogeneous MAP kinase reporter gene screen for the identification of agonists and antagonists at the CXCR1 chemokine receptor

Agonist activity at G protein-coupled receptors (GPCRs) that regulate heterotrimeric G proteins of the Galpha(i/o) or Galpha(q) families has been shown to result in activation of the mitogen-activated protein (MAP) kinase cascade. To facilitate compound screening for these classes of GPCR, we have developed a reporter gene that detects the activation of the ternary complex transcription factor Sap1a following MAP kinase activation. In contrast to other reporter gene assays for Galpha(i/o)-coupled GPCRs, the MAP kinase reporter generates an increase in signal in the presence of agonist. The reporter gene has been transfected into Chinese hamster ovary cells to generate a "host" reporter gene-containing cell line. The Galpha(i)-coupled human CXCR1 chemokine receptor was subsequently transfected into this cell line in order to develop a 384-well format screen for both agonists and antagonists of this receptor. Agonists activated the reporter gene with the expected rank order of potency and with similar concentration dependence as seen with the regulation of other signal transduction cascades in mammalian cells: interleukin-8 (IL-8) (pEC(50) = 7.0 +/- 0.1) > GCP-2 (pEC(50) = 6.3 +/- 0.1) > NAP-2 (pEC(50) < 6). CXCR1-mediated activation of MAP kinase was inhibited by pertussis toxin and the MEK inhibitor PD98059, demonstrating that receptor activation of MAP kinase is due to pertussis toxin-sensitive Galpha(i/o)-family G proteins to cause the activation of MEK kinase. Using the 384-well format, assay performance was unaffected by solvent concentrations of 0.5% ethanol, 0.15% glycerol, or 1% DMSO. Signal crosstalk between adjacent wells was less than 1%. The assay exhibited a Z factor of 0.53 and a coefficient of variation of response to repeated application of IL-8 (100 nM) of 15.9%.

A novel carbohydrate:acceptor oxidoreductase from Microdochium nivale

A Microdochium nivale carbohydrate:acceptor oxidoreductase was purified, cloned, heterologously expressed, and characterized. The gene encoding the protein showed one intron, and the ORF showed a sequence with low homology (< or = 25% identity or 65% similarity) to other known flavin-containing carbohydrate oxidases. The maturation of the protein required the cleavage of a tetrameric propeptide in addition to an 18 amino-acid signal peptide. The enzyme was found to have a relative molecular mass of 55 000 Da, an isoelectric point of 9, and one FAD per protein. It could oxidize mono-, oligo-, or polymeric saccharides, and transfer their electrons to O2 or other acceptors. When D-glucose served as electron-donating substrate, an activity of 2 s(-1) was observed at pH 5.5 and 23 degrees C. Among various oligosaccharides, the enzyme preferred tetrameric dextrins, indicating a favorable interaction of four linked glucose units with the substrate pocket. The unique structure and ability of oxidizing oligo/polymeric saccharides suggest a promising prospect of this enzyme for various industrial/medicinal applications.

Usability evaluation of the progress note construction set

OVERVIEW

The Veterans Administration (VA) Computerized Patient Record System (CPRS) is a nationally deployed software product that integrates provider order entry, progress notes, vitals, consults, discharge summaries, problem lists, medications, labs, radiology, transcribed documents, study reports, and clinical reminders. Users rapidly adopted the graphical user interface for data retrieval, but demanded options to typing for data entry. We programmed "point and click" forms that integrate with CPRS individually, but were soon overwhelmed by requests. Subsequently, we developed the Progress Note Construction Set (PNCS); a tool suite that permits subject matter experts without programming skills to create reusable "point and click" forms. In this study, we evaluate the usability of these user-constructed forms.

METHODS

An untrained, non-VA subject matter expert used the PNCS to create a graphical form for "skin tear" documentation. Ten VA nurses used the skin tear form to document findings for 7 standardized clinical scenarios. Following each scenario the subjects answered usability questions about the form.

RESULTS

The subject matter expert created the skin tear form in 78 minutes. Users found the form to facilitate their data entry (p 0.0265), and to be at least as fast (p 0.0029) and as easy to use as expected (p 0.0166). Average note entry time was 3.4 minutes.

CONCLUSION

The PNCS allowed a non-programmer to quickly create a usable, CPRS-integrated point and click form. Users found the subject matter expert s form fast and easy to use. The tool suite is a more scaleable form creation method because capacity is no longer limited by programmer availability.

Derivation and evaluation of a document-naming nomenclature

OBJECTIVE

The Computerized Patient Record System is deployed at all 173 Veterans Affairs (VA) medical centers. Providers access clinical notes in the system from a note title menu. Following its implementation at the Nashville VA Medical Center, users expressed dissatisfaction with the time required find notes among hundreds of irregularly structured titles. The authors' objective was to develop a document-naming nomenclature (DNN) that creates informative, structured note titles that improve information access.

DESIGN

One thousand ninety-four unique note titles from two VA medical centers were reviewed. A note-naming nomenclature and compositional syntax were derived. Compositional order was determined by user preference survey.

MEASUREMENTS

The DNN was evaluated by modeling note titles from the Salt Lake City VA Medical Center (n=877), Vanderbilt University Medical Center (n=554), and the Mayo Clinic (n=42). A preliminary usability evaluation was conducted on a structured title display and sorting application.

RESULTS

Classes of note title components were found by inspection. Components describe characteristics of the author, the health care event, and the organizational unit providing care. Terms were taken from VA medical center information systems and national standards. The DNN model accurately described 97 to 99 percent of note titles from the test sites. The DNN term coverage varied, depending on component and site. Users found the DNN title format useful and the DNN-based title sorting and note review application easy to learn and quick to use.

CONCLUSION

The DNN accurately models note titles at five medical centers. Preliminary usability data indicate that DNN integration with title parsing and sorting software enhances information access.

A randomized controlled trial of the accuracy of clinical record retrieval using SNOMED-RT as compared with ICD9-CM

BACKGROUND

Concept-based Indexing is purported to provide more granular data representation for clinical records.1,2 This implies that a detailed clinical terminology should be able to provide improved access to clinical records. To date there is no data to show that a clinical reference terminology is superior to a precoordinated terminology in its ability to provide access to the clinical record. Today, ICD9-CM is the most commonly used method of retrieving clinical records.

OBJECTIVE

In this study, we compare the sensitivity, specificity, positive likelihood ratio, positive predictive value and accuracy of SNOMED-RT vs. ICD9-CM in retrieving ten diagnoses from a random sample of 2,022 episodes of care.

METHOD

We randomly selected 1,014 episodes of care from the inpatient setting and 1,008 episodes of care from the outpatient setting. Each record had associated with it, the free text final diagnoses from the Master Sheet Index at the Mayo Clinic and the ICD9-CM codes used to bill for the encounters within the episode of care. The free text diagnoses were coded by two expert indexers (disagreements were addressed by a Staff Clinician) as to whether queries regarding one of 5 common or 5 uncommon diagnoses should return this encounter. The free text entries were automatically coded using the Mayo Vocabulary Processor. Each of the ten diagnoses was exploded in both SNOMED-RT and ICD9-CM and using these entry points, a retrieval set was generated from the underlying corpus of records. Each retrieval set was compared with the Gold Standard created by the expert indexers.

RESULTS

SNOMED-RT produced significantly greater specificity in its retrieval sets (99.8% vs. 98.3%, p<0.001 McNemar Test). The positive likelihood ratios were significantly better for SNOMED-RT retrieval sets (264.9 vs. 33.8, p<0.001 McNemar Test). The positive predictive value of a SNOMED-RT retrieval was also significantly better than ICD9-CM (92.9% vs. 62.4%, p<0.001 McNemar Test). The accuracy defined as 1 (the total error rate (FP+FN) / Total # episodes queried (20,220)) was significantly greater for SNOMED-RT (98.2% vs. 96.8%, p=0.002 McNemar Test). Interestingly, the sensitivity of the SNOMED-RT generated retrieval set was not significantly different from ICD9-CM, but there was a trend toward significance (60.4% vs. 57.6%, p=0.067 McNemar Test). However, if we examine only the outpatient practice SNOMED-RT produced a more sensitive retrieval set than ICD9-CM (54.8% vs. 46.4%, p=0.002 McNemar Test).

CONCLUSIONS

Our data clearly shows that information regarding both common and rare disorders is more accurately identified with automated SNOMED-RT indexing using the Mayo Vocabulary Processor than it is with traditional hand picked constellations of codes using ICD9-CM. SNOMED-RT provided more sensitive retrievals of outpatient episodes of care than ICD9-CM.

Motor control testing of upper limb function after botulinum toxin injection: a case study

OBJECTIVE

To evaluate changes in upper extremity function in a hemiparetic patient after treatment with botulinum toxin (BTX) using motor-control testing (MCT) techniques.

DESIGN

Interventional with longitudinal study, open label.

SETTING

A children's hospital and a motor-control laboratory at a major academic center.

PARTICIPANTS

A 16-year-old male with right hemiparetic cerebral palsy and a healthy 12-year-old control subject.

INTERVENTIONS

BTX injections to the elbow and wrist flexors.

MAIN OUTCOME MEASURES

MCT was used to examine 4 upper extremity movements: forward reach, bilateral rhythmic movements (both muscle homologous and direction homologous), isometric pinch, and hand tapping. The patient was tested before treatment and at 2, 4, 6, 12, 18, and 24 weeks after treatment. In addition, range of motion (ROM), the Ashworth scale of spasticity, Functional Independence Measure, and the mobility and activities of daily living (ADL) sections of the Pediatric Evaluation of the Disability Inventory were performed.

RESULTS

Forward reach demonstrated little change initially despite patient reports of "feeling looser." Improvement was noted after 18 weeks, but returned to baseline level at 24 weeks. Bilateral rhythmic movements also showed slight improvement at 18 weeks. Pinch force increased significantly after 2 weeks, but declined again at 6 weeks. Improvements occurred in ROM and the Ashworth rating of spasticity, but were not temporally associated with each other or with MCT results. Functional assessment data did not change during the study period.

CONCLUSIONS

Improvements in more complex motor tasks were noted after significant delay from the time of treatment, while simpler tasks demonstrated a more rapid improvement, followed by a rapid return to baseline levels. This case suggests that MCT techniques can provide quantitative and qualitative data, which can add new information about upper extremity motor disability and the outcome of treatment.

Using DNA-tagged mutagenesis to improve heterologous protein production in Aspergillus oryzae

Using DNA-tagged mutagenesis to improve heterologous protein production in Aspergillus oryzae. Fungal Genetics and Biology 29, 28-37. Restriction enzyme-mediated integration (REMI) has been employed as a mutagen to generate two insertion libraries in an Aspergillus oryzae strain expressing a Thermomyces lanuginosus lipase. The REMI libraries were created using linearized plasmid containing the A. oryzae pyrG and either BamHI or EcoRI enzyme. The libraries were screened for lipase production, and mutants with increased production were isolated. The genomic DNA flanking the integration event was cloned from one of the mutants with increased lipase titers (DEBY10.3). Nucleotide sequence of the flanking DNA revealed similarity to the Aspergillus nidulans palB gene. Disruption of the palB gene in a strain producing lipase resulted in increased lipase expression. Additionally, complementation of the palB phenotype of DEBY10.3 led to a decrease in lipase production. These lines of evidence demonstrate that the increase in lipase yield in DEBY10.3 is linked to the palB phenotype generated by the integration of the pyrG gene into the palB gene. The results also demonstrated that tagged mutagenesis with REMI can be used to identify genes that influence expression of heterologous proteins.

Molecular characterization of laccase genes from the basidiomycete Coprinus cinereus and heterologous expression of the laccase lcc1

A laccase from Coprinus cinereus is active at alkaline pH, an essential property for some potential applications. We cloned and sequenced three laccase genes (lcc1, lcc2, and lcc3) from the ink cap basidiomycete C. cinereus. The lcc1 gene contained 7 introns, while both lcc2 and lcc3 contained 13 introns. The predicted mature proteins (Lcc1 to Lcc3) are 58 to 80% identical at the amino acid level. The predicted Lcc1 contains a 23-amino-acid C-terminal extension rich in arginine and lysine, suggesting that C-terminal processing may occur during its biosynthesis. We expressed the Lcc1 protein in Aspergillus oryzae and purified it. The Lcc1 protein as expressed in A. oryzae has an apparent molecular mass of 66 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and absorption maxima at 278 and 614 nm. Based on the N-terminal protein sequence of the laccase, a 4-residue propeptide was processed during the maturation of the enzyme. The dioxygen specificity of the laccase showed an apparent K(m) of 21 +/- 2 microM and a catalytic constant of 200 +/- 10 min(-1) for O(2) with 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) as the reducing substrate at pH 5.5. Lcc1 from A. oryzae may be useful in industrial applications. This is the first report of a basidiomycete laccase whose biosynthesis involves both N-terminal and C-terminal processing.

Empirical derivation of an electronic clinically useful problem statement system

Problem lists are tools to improve patient management. In the medical record, they connect diagnoses to therapy, prognosis, and psychosocial issues. Computer-based problem lists enhance paper-based approaches by enabling cost-containment and quality assurance applications, but they require clinically expressive controlled vocabularies. Because existing controlled vocabularies do not represent problem statements at a clinically useful level, we derived a new canonical problem statement vocabulary through semi-automated analysis and distillation of provider-entered problem lists collected over 6 years from 74,696 patients. We combined automated and manual methods to condense 891,770 problem statements entered by 1961 care providers at Grady Memorial Hospital in Atlanta, Georgia, to 15,534 Canonical Clinical Problem Statement System (CCPSS) terms. The nature and frequency of problem statements were characterized, interrelations among them were enumerated, and a database capturing the epidemiology of problems was created. The authors identified 23,503 problem relations (co-occurrences, sign-symptom complexes, and differential diagnoses) and 22,690 modifier words that further categorized "canonical" problems. To assess completeness, CCPSS content was compared with that of the 1997 Unified Medical Language System Metathesaurus (containing terms from 44 clinical vocabularies). Unified Medical Language System terms expressed 25% of individual CCPSS terms exactly (71% of problems by frequency), 27% partially, and 48% poorly or not at all. Clinicians judged that CCPSS terms completely captured their clinical intent for 84% of 686 randomly selected free-text problem statements. The CCPSS represents clinical concepts at a level exceeding that of previous approaches. A similar national approach could create a standardized, useful, shared resource for clinical practice.

Targeted mutations in a Trametes villosa laccase. Axial perturbations of the T1 copper

Trametes villosa laccase was mutated on a tetrapeptide segment near the type 1 site. The mutations F463M and F463L were at the position corresponding to the type 1 copper axial methionine (M517) ligand in Zucchini ascorbate oxidase. The mutations E460S and A461E were near the T1 copper site. The mutated Trametes laccases were expressed in an Aspergillus oryzae host and characterized. The E460S mutation failed to produce a transformant with meaningful expression. The F463L and A461E mutations did not significantly alter the molecular and enzymological properties of the laccase. In contrast, the F463M mutation resulted in a type 1 copper site with an EPR signal intermediate between that of the wild type laccase and plastocyanin, an altered UV-visible spectrum, and a decreased redox potential (by 0.1 V). In oxidizing phenolic substrate, the mutation led to a more basic optimal pH as well as an increase in kcat and Km. These effects are attributed to a significant perturbation of the T1 copper center caused by the coordination of the axial methionine (M463) ligand.

No free lunch: institutional preparations for computer-based patient records

The Veterans Administration (VA) is aggressively pursuing computer-based medical records by deploying the Computerized Patient Record System (CPRS) across its 150 medical centers and 400 outpatient clinics. CPRS's client-server, patient-centered approach to clinical computing is a departure from VA's traditional terminal-compatible, department-centered approach. Although the CPRS software is freely distributed, institutional readiness for computer-based patient records has proven expensive. Preparations include organizational changes, human resource development, hardware deployment, physical plant upgrades, and software testing. This paper details CPRS preparations and their costs at one VA Medical Center. Lessons learned during the process are summarized.

Site-directed mutations in fungal laccase: effect on redox potential, activity and pH profile

A Myceliophthora thermophila laccase and a Rhizoctonia solani laccase were mutated on a pentapeptide segment believed to be near the type-1 Cu site. The mutation L513F in Myceliophthora laccase and the mutation L470F in Rhizoctonia laccase took place at a position corresponding to the type-1 Cu axial methionine (M517) ligand in Zucchini ascorbate oxidase. The triple mutations V509L,S510E,G511A in Myceliophthora laccase and L466V,E467S,A468G in Rhizoctonia laccase involved a sequence segment whose homologue in ascorbate oxidase is flanked by the M517 and a type-1 Cu-ligating histidine (H512). The single mutation did not yield significant changes in the enzymic properties (including any significant increase in the redox potential of the type-1 Cu). In contrast, the triple mutation resulted in several significant changes. In comparison with the wild type, the Rhizoctonia and Myceliophthora laccase triple mutants had a phenol-oxidase activity whose pH optimum shifted 1 unit lower and higher, respectively. Although the redox potentials were not significantly altered, the Km, kcat and fluoride inhibition of the laccases were greatly changed by the mutations. The observed effects are interpreted as possible mutation-induced structural perturbations on the molecular recognition between the reducing substrate and laccase and on the electron transfer from the substrate to the type-1 Cu centre.

Crystal structure of the type-2 Cu depleted laccase from Coprinus cinereus at 2.2 A resolution

Laccase catalyses the oxidation of a variety of organic substrates coupled to the reduction of oxygen to water. It is widely believed to be the simplest representative of the ubiquitous blue multi-copper oxidase family. Laccase is implicated in a wide spectrum of biological activities and, in particular, plays a key role in morphogenesis, development and lignin metabolism in fungi and plants. The structure of laccase from the fungus Coprinus cinereus has been determined by X-ray crystallography at a resolution of 2.2 A. Laccase is a monomer composed of three cupredoxin-like beta-sandwich domains, similar to that found in ascorbate oxidase. In contrast to ascorbate oxidase, however, the mononuclear type-1 Cu site lacks the axial methionine ligand and so exhibits trigonal planar coordination, consistent with its elevated redox potential. Crucially, the structure is trapped in a Cu depleted form in which the putative type-2 Cu atom is completely absent, but in which the remaining type-1 and type-3 Cu sites display full occupancy. Type-2 Cu depletion has unexpected consequences for the coordination of the remaining type-3 Cu atoms.

Crystallization and preliminary X-ray analysis of the laccase fromCoprinus cinereus

The laccase from the fungus Coprinus cinereus has been prepared and crystallized in a form suitable for X-ray diffraction analysis. Small plate-like crystals of an enzymatically deglycosylated form of the enzyme have been grown by the hanging-drop method using polyethylene glycol as precipitant. These crystals diffract to at least 2.2 A. They belong to the space group P2(1)2(1)2(1) with cell dimensions a = 45.4, b = 85.7, c = 143.1 A with a single molecule of laccase in the asymmetric unit.

Characterization of the gene encoding an extracellular laccase of Myceliophthora thermophila and analysis of the recombinant enzyme expressed in Aspergillus oryzae

A genomic DNA segment encoding an extracellular laccase was isolated from the thermophilic fungus Myceliophthora thermophila, and the nucleotide sequence of this gene was determined. The deduced amino acid sequence of M. thermophila laccase (MtL) shows homology to laccases from diverse fungal genera. A vector containing the M. thermophila laccase coding region, under transcriptional control of an Aspergillus oryzae alpha-amylase gene promoter and terminator, was constructed for heterologous expression in A. oryzae. The recombinant laccase expressed in A. oryzae was purified to electrophoretic homogeneity by anion-exchange chromatography. Amino-terminal sequence data suggests that MtL is synthesized as a preproenzyme. The molecular mass was estimated to be approximately 100 to 140 kDa by gel filtration on Sephacryl S-300 and to be 85 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Carbohydrate analysis revealed that MtL contains 40 to 60% glycosylation. The laccase shows an absorbance spectrum that is typical of blue copper oxidases, with maxima at 276 and 589 nm, and contains 3.9 copper atoms per subunit. With syringaldazine as a substrate, MtL has optimal activity at pH 6.5 and retains nearly 100% of its activity when incubated at 60 degrees C for 20 min. This is the first report of the cloning and heterologous expression of a thermostable laccase.

Quantification of upper extremity function using kinematic analysis

OBJECTIVE

To illustrate the applicability of motor control analytical techniques to the assessment of upper limb dysfunction in children with ataxia.

DESIGN

Descriptive case series.

SETTING

The study sample was selected from an outpatient pediatric rehabilitation clinic and testing was performed in a research laboratory.

PARTICIPANTS

Four children with upper limb ataxia and seven healthy children were examined. All subjects were recruited on a volunteer basis. Criteria for inclusion (ataxic group) included: (1) age 6 to 15 yrs; (2) ambulatory with assistive devices.

MAIN OUTCOME MEASURES

Quantitative measures of elbow kinematics (movement speed and duration) and spatio-temporal "portraits" of elbow movement during unilateral and bilateral forward reaching movements.

RESULTS

Movements made by ataxic subjects were characterized by lower peak velocities, prolonged durations, and increased variability compared with normal subjects. In the one subject with unilateral ataxia, interlimb coordination was severely disrupted during the performance of coupled, bilateral arm movements. In addition to changes in specific kinematic values (eg, peak velocity), phase plane and angle-angle displacement curves revealed marked spatio-temporal variability throughout the movement, the magnitude of which was correlated with severity of ataxia.

CONCLUSION

The application of the quantitative motor control methods described in this report can provide rehabilitation specialists with a simple yet sensitive means to evaluate treatment and progression of a wide variety of motor disorder conditions. These techniques are particularly well suited to pediatric populations as young as 6 years.

Rhythmic auditory-motor facilitation of gait patterns in patients with Parkinson's disease

OBJECTIVES

The effect of rhythmic auditory stimulation (RAS) on gait velocity, cadence, stride length, and symmetry was studied in 31 patients with idiopathic Parkinson's disease, 21 of them on (ON) and 10 off medication (OFF), and 10 healthy elderly subjects.

METHOD

Patients walked under four conditions: (1) their own maximal speed without external rhythm; (2) with the RAS beat frequency matching the baseline cadence; (3) with RAS 10% faster than the baseline cadence; (4) without rhythm to check for carry over from RAS. Gait data were recorded via a computerised foot switch system. The RAS was delivered via a 50 ms square wave tone embedded in instrumental music (Renaissance style) in 2/4 metre prerecorded digitally on a sequencer for variable tempo reproduction. Patients on medication were tested in the morning 60-90 minutes after medication. Patients off medication were tested at the same time of day 24 hours after the last dose. Healthy elderly subjects were tested during the same time of day.

RESULTS

Faster RAS produced significant improvement (P < 0.05) in mean gait velocity, cadence, and stride length in all groups. Close synchronisation between rhythm and step frequency in the controls and both Parkinson's disease groups suggest evidence for rhythmic entrainment mechanisms even in the presence of basal ganglia dysfunction.

CONCLUSIONS

The results are consistent with and extend prior reports of rhythmic auditory facilitation in Parkinson's disease gait when there is mild to moderate impairment, and suggest a technique for gait rehabilitation in Parkinson's disease.

Cross-institutional reuse of a problem statement knowledge base

This article describes client and server applications for a problem statement knowledge base derived from a large corpus of provider entered terminology. The current status and potential for integration of the server into the Vanderbilt University Medical Center computing environment are discussed. Finally, an experiment in multiple dimensions of reuse for problem list terms is introduced, and possible strategies to mediate between free text and coded data are examined.

Basal ganglia and cerebellar impairment differentially affect the amplitude and time scaling during the performance of forearm step tracking movements

Forearm step tracking movements of different amplitudes were analysed in nine patients with cerebellar and five patients with parkinsonian symptoms in comparison to six normal subjects. Movements were made under two instructions: 1) track "as fast as possible" and 2) "as precisely as possible". Movement duration, acceleration duration and peak velocity increased with increasing amplitude. The ratio between acceleration and deceleration duration was independent of movement amplitude in the parkinsonian patients and the normal subjects. In the cerebellar patients, however, this ratio decreased with increasing amplitude. This impairment of the relative timing between acceleration and deceleration duration implies that, in contrast to parkinsonian patients, cerebellar patients cannot anymore utilize physiological scaling mechanisms when performing movements of different amplitudes.

Purification, characterization, molecular cloning, and expression of two laccase genes from the white rot basidiomycete Trametes villosa

Two laccases have been purified to apparent electrophoretic homogeneity from the extracellular medium of a 2,5-xylidine-induced culture of the white rot basidiomycete Trametes villosa (Polyporus pinsitus or Coriolus pinsitus). These proteins are dimeric, consisting of two subunits of 63 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and have typical blue laccase spectral properties. Under nondenaturing conditions, the two purified laccases have different pIs; purified laccase forms 1 and 3 have pIs of 3.5 and 6 to 6.5, respectively. A third purified laccase form 2 has the same N terminus as that of laccase form 3, but its pI is in the range of 5 to 6. The laccases have optimal activity at pH 5 to 5.5 and pH < or = 2.7 with syringaldazine and ABTS [2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)] as substrates, respectively. The genes lcc1 and lcc2 coding for the two purified laccases (forms 1 and 3) have been cloned, and their nucleotide sequences have been determined. The genes for lcc1 and lcc2 have 8 and 10 introns, respectively. The predicted proteins are 79% identical at the amino acid level. From Northern (RNA) blots containing total RNA from both induced and uninduced cultures, expression of lcc1 is highly induced, while the expression of lcc2 appears to be constitutive. Lcc1 has been expressed in Aspergillus oryzae, and the purified recombinant protein has the same pI, spectral properties, stability, and pH profiles as the purified native protein.

The identification and characterization of four laccases from the plant pathogenic fungus Rhizoctonia solani

Four distinct laccase genes, lcc1, lcc2, lcc3 and lcc4, have been identified in the fungus Rhizoctonia solani. Both cDNA and genomic copies of these genes were isolated and characterized. Hybridization analyses indicate that each of the four laccase genes is present in a single copy in the genome. The R. solani laccases can be divided into two groups based on their protein size, intron/exon organization, and transcriptional regulation. Three of these enzymes have been expressed in the fungus Aspergillus oryzae. Two of the recombinant laccases, r-lcc1 and r-lcc4, as well as the native lcc4 enzyme were purified and characterized. The purified proteins are homodimeric, comprised of two subunits of approximately 66kDa for lcc4 and 50-100kDa for the recombinant lcc1 protein. These laccases have spectral properties that are consistent with other blue copper proteins. With syringaldazine as a substrate, lcc4 has optimal activity at pH7, whereas lcc1 has optimal activity at pH6.

A study of a series of recombinant fungal laccases and bilirubin oxidase that exhibit significant differences in redox potential, substrate specificity, and stability

A series of fungal laccases (Polyporus pinsitus, Rhizoctonia solani, Myceliophthora thermophila, Scytalidium thermophilum) and one bilirubin oxidase (Myrothecium verrucaria) have been studied to determine their redox potential, specificity, and stability. Polyporus and Rhizoctonia laccases possess potentials near 0.7-0.8 V (vs. NHE), while other oxidases have potentials near 0.5 V. It is observed that higher redox potential correlates with higher activity. By EPR, no significant change in the geometry of type 1 copper (II) site is observed over this series. At the optimal pH, the two substrates studied, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) and syringaldazine, show Km values ranging form 10 to 120 and from 1 to 45 microM; and kcat values ranging from 50 to 16 000 and 200 to 3000 per min, respectively. The enzymes are more stable in the neutral-alkaline pH range. The thermal stability is in the order of bilirubin oxidase equivalent to Myceliophthora laccase equivalent to Scytalidium laccase > Polyporus laccase > Rhizoctonia laccase. Based on these results and the sequence alignments made against Zucchini ascorbate oxidase it is speculated that structural differences in the substrate-activation site (a 'blue', type 1 copper center) control the redox potential range as well as substrate specificity, and the cystine content contributes to stability.

Fusarium graminearum A 3/5 as a novel host for heterologous protein production

We describe a novel fungal expression system which utilizes the Quorn myco-protein fungus Fusarium graminearum A 3/5. A transformation system was developed for F. graminearum and was used to introduce the coding and regulatory regions of a trypsin gene from Fusarium oxysporum. The protein was efficiently expressed, processed and secreted by the recombinant host strain. In addition, the promoter and terminator of the F. oxysporum trypsin gene have been successfully utilized to drive the expression of a cellulase gene from Scytalidium thermophilum and a lipase gene from Thermomyces lanuginosus in F. graminearum.

Effects of gravitational forces on single joint arm movements in humans

We have examined the kinematics and muscle activation patterns of single joint elbow movements made in the vertical plane. Movements of different amplitudes were performed during a visual, step-tracking task. By adjusting shoulder position, both elbow flexion and extension movements were made under three conditions: (a) in the horizontal plane, (b) in the vertical plane against gravity, and (c) in the vertical plane with gravity. Regardless of the gravitational load, all movements were characterized by time symmetric velocity profiles. In addition, no differences were found in the relationships between movement duration, peak velocity, and movement amplitude in movements with or against gravity. The pattern of muscle activation was influenced however, by the gravitational load. Both flexion and extension movements made with gravity were characterized by a reciprocally organized pattern of muscle activity in which phasic agonist activity was followed by phasic antagonist activity. Flexion and extension movements made against gravity were characterized by early phasic antagonist activity occurring at about the same time as the initial agonist burst. These findings suggest that EMG patterns are modified in order to preserve a common temporal structure in the face of different gravitational loads.

Aspirin and nonsteroidal anti-inflammatory drug use and the risk of subsequent colorectal cancer

OBJECTIVE

To test the hypothesis that the regular use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) is negatively associated with the risk of subsequent colorectal cancer.

DESIGN

Case-control study with four age- and sex-matched control subjects for each incident colorectal cancer case.

POPULATION AND SETTING

Patient population of a large municipal teaching hospital in Atlanta, Ga.

MAIN OUTCOME MEASURE

Odds of colorectal cancer as a function of aspirin, nonaspirin NSAIDs, and acetaminophen dispensed to the study population in the 4 years prior to incident colorectal cancer diagnosis.

MAIN RESULTS

The risk of colorectal cancer estimated by odds ratios decreased with increasing days of exposure to aspirin linearly in a dose-dependent fashion (likelihood ratio statistic: for cumulative days, P < .001; for cumulative dose, P < .001). The coefficient for days of exposure to aspirin was highly significant even when modeled as a continuous variable (P = .001). There appeared to be a threshold above which nonaspirin NSAIDs afforded protection (likelihood ratio statistic: for cumulative days, P = .021; for cumulative dose, P = .019). Acetaminophen conferred no risk reduction.

CONCLUSION

The results of previous experimental animal models, interventional case studies, and some but not all epidemiological investigations and the present data point toward a causal relationship between NSAID use and the prevention of cancer of the large bowel and rectum. Because of the potential gastrointestinal and renal side effects of NSAID use, particularly in the elderly, chemoprevention trials are now needed to allow risk-benefit analysis in populations at high risk for colorectal cancer.

Changes in physicians' computer anxiety and attitudes related to clinical information system use

STUDY OVERVIEW: Interns' anxiety about computer use ("computer anxiety") and their attitudes toward medical computer applications were determined by a standardized questionnaire. Participants were surveyed before and after three months of differential exposure to three clinical information systems (CISs), including one with provider-entered encounters.

POPULATION

Fifty-one interns completed both surveys. Their average age was 27 years. Thirty-three percent were female, 7% were African American, and 8% were foreign graduates.

RESULTS

The most common previous exposures to computers were for literature searching and retrieval of patient information (both 92%). Factors that commonly emerged as predictive of anxiety about computer use included self-rated skills, typing ability, and computer attitudes. Factors predictive of attitudes toward computers included self-rated skills, typing ability, maximal frequency of prior computer use, computer ownership, and computer anxiety. Factors that were not predictive of computer anxiety or attitudes toward computers included age, gender, and physician input of data.

CONCLUSION

Identification of markers for negative psychological reactions to computer use may allow development of interventions to improve acceptance of computer base patient records (CBPRs).

Movement-related phasic muscle activation. III. The duration of phasic agonist activity initiating movement

To test the hypothesis that phasic muscle activation is related to the acceleration-deceleration characteristics of the resulting movement, we examined the relation between the duration of the acceleratory phase of a variety of movement types and the duration of the phasic muscle activity producing the acceleration (the initial agonist burst, AG1). Movements of five types were studied: (1) step-tracking movements of different amplitudes (10-90 deg) and durations (200-800 ms), (2) movements of the same amplitude (40 deg) and duration (600 ms) varying only in their symmetry ratio (SR, ratio of acceleration to deceleration durations), (3) movements in which acceleration duration was changed while acceleration magnitude was held constant, (4) oscillatory movements of different frequencies and peak amplitudes, (5) step-tracking movements against different inertial loads. Subjects made movements about the elbow joint in the horizontal plane. Surface electromyographic (EMG) activity was recorded from the biceps and the lateral head of the triceps muscles. Under all movement conditions tested and with acceleration duration ranging from 100 to 500 ms, acceleration duration varied linearly with the duration of AG1. Correlation coefficients for the linear regression lines ranged from 0.8 to 0.99. The slope of the best fit linear regression lines ranged from 0.5 to 1.6 and tended to be higher for extensions than flexions. The variations in slope may arise from differing mechanical properties of the biceps and triceps muscles, as well as from active forces produced in the antagonist. AG1 duration was unchanged by inertial loading when subjects kept acceleration duration constant. If subjects responded to an increase in inertial load with an increase in acceleration duration, there was a corresponding increase in AG1 duration. The data demonstrate a general relation between one characteristic of muscle activation (AG1 duration) and the resulting movement. The linear form of the relation is invariant across movement amplitude (range 10-90 deg), speed, duration (range 200-800 ms) and temporal profile (SR range 0.3-2.7), and is also independent of movement type (step, oscillatory). Such a general and simple relation between EMG and movement suggests that, at least to a first approximation, the nervous system can rather simply determine the muscle activation patterns needed to produce movements with desired characteristics.

Regulation of ribosomal RNA transcription by growth rate of the hyperthermophilic Archaeon, Pyrococcus furiosus

We have studied the single rRNA gene cluster from the Archaeon, Pyrococcus furiosus. This isolate grows optimally at 100 degrees C and is thus a hyperthermophile. In P. furiosus, transcription of 16S rRNA is subject to regulation over a 7.5-fold range in response to a 20-fold increase in growth rate. The single cluster encoding the 16S and 23S rRNA genes of P. furiosus was cloned and the 1.9 kb region upstream of the 16S rRNA gene was sequenced.

Role of the cerebellum in visuomotor coordination. I. Delayed eye and arm initiation in patients with mild cerebellar ataxia

The initiation of coupled eye and arm movements was studied in six patients with mild cerebellar dysfunction and in six age-matched control subjects. The experimental paradigm consisted of 40 deg step-tracking elbow movements made under different feedback conditions. During tracking with the eyes only, saccadic latencies in patients were within normal limits. When patients were required to make coordinated eye and arm movements, however, eye movement onset was significantly delayed. In addition, removal of visual information about arm versus target position had a pronounced differential effect on movement latencies. When the target was extinguished for 3 s immediately following a step change in target position, both eye and arm onset times were further prolonged compared to movements made to continuously visible targets. When visual information concerning arm position was removed, onset times were reduced. Eye and arm latencies in control subjects were unaffected by changes in visual feedback. The results of this study clearly demonstrate that, in contrast to earlier reports of normal saccadic latencies associated with cerebellar dysfunction, initiation of both eye and arm movements is prolonged during coordinated visuomotor tracking thus supporting a coordinative role for the cerebellum during oculo-manual tracking tasks.

Enzymes from high-temperature microorganisms

Enzymes derived from microorganisms growing at extreme temperatures are of biotechnological use as highly thermostable biocatalysts and should provide insight into the intrinsic basis of protein stability. So far, only DNA polymerases from these organisms have been put to commercial use, although the application of other classes of highly thermostable enzymes is being considered. Problems in the cultivation of high-temperature microorganisms and in the production of their enzymes still hampers progress in this field.

Purification and characterization of an alpha-glucosidase from a hyperthermophilic archaebacterium, Pyrococcus furiosus, exhibiting a temperature optimum of 105 to 115 degrees C

Pyrococcus furiosus is a strictly anaerobic hyperthermophilic archaebacterium with an optimal growth temperature of about 100 degrees C. When this organism was grown in the presence of certain complex carbohydrates, the production of several amylolytic enzymes was noted. These enzymes included an alpha-glucosidase that was located in the cell cytoplasm. This alpha-glucosidase has been purified 310-fold and corresponded to a protein band of 125 kilodaltons as resolved by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme exhibited optimum activity at pH 5.0 to 6.0 and over a temperature range of 105 to 115 degrees C. Kinetic analysis conducted at 108 degrees C revealed hydrolysis of the substrates p-nitrophenyl-alpha-D-glucopyranoside (PNPG), methyl-alpha-D-glucopyranoside, maltose, and isomaltose. Trace activity was detected towards p-nitrophenyl-beta-D-glucopyranoside, and no activity could be detected towards starch or sucrose. Inhibition studies conducted at 108 degrees C with PNPG as the substrate and maltose as the inhibitor yielded a Ki for maltose of 14.3 mM. Preincubation for 30 min at 98 degrees C in 100 mM dithiothreitol and 1.0 M urea had little effect on enzyme activity, whereas preincubation in 1.0% sodium dodecyl sulfate and 1.0 M guanidine hydrochloride resulted in significant loss of enzyme activity. Purified alpha-glucosidase from P. furiosus exhibited remarkable thermostability; incubation of the enzyme at 98 degrees C resulted in a half life of nearly 48 h.

Characterization of Amylolytic Enzyme Activities Associated with the Hyperthermophilic Archaebacterium Pyrococcus furiosus

The hyperthermophilic archaebacterium Pyrococcus furiosus produces several amylolytic enzymes in response to the presence of complex carbohydrates in the growth medium. These enzyme activities, α-glucosidase, pullulanase, and α-amylase, were detected in both cell extracts and culture supernatants. All activities were characterized by temperature optima of at least 100°C as well as a high degree of thermostability. The existence of this collection of activities in P. furiosus suggests that polysaccharide availability in its growth environment is a significant aspect of the niche from which it was isolated.