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PubMed2004

Development of an ideal starch saccharification process using amylolytic enzymes from thermophiles.

The extensive efforts to screen thermophilic fungi and bacteria, isolated from various environmental samples, have resulted in the selection of Thermomucor indicae-seudaticae, Geobacillus thermoleovorans NP33 and G. thermoleovorans NP54 for the production of glucoamylase, amylopullulanase and alpha-amylase, respectively. Submerged and solid-state fermentation processes were optimized for maximizing the secretion of glucoamylase by T. indicae-seudaticae. The production of amylopullulanase and alpha-amylase by NP33 and NP54 in submerged fermentation was also optimized. Glucoamylase was optimally active at pH 7.0 and 60 degrees C and was shown to saccharify soluble as well as raw starches. Amylopullulanase and alpha-amylase exhibited optima at pH 7.0 and 100 degrees C and saccharified starch efficiently. Differential inhibition and action on mixed substrates clearly suggested that there are two separate active sites for alpha-amylase and pullulanase activities of amylopullulanase. Both alpha-amylase and amylopullulanase are high maltose-forming and Ca(2+)-independent. These amylolytic enzymes have been shown to be useful in starch saccharification alone and in combination.

Amyloid↗
PubMed2005

Proteasomes.

The major enzyme system catalysing the degradation of intracellular proteins is the proteasome system. A central inner chamber of the cylinder-shaped 20 S proteasome contains the active site, formed by N-terminal threonine residues. The 20 S proteasomes are extremely inefficient in degrading folded protein substrates and therefore one or two multisubunit 19 S regulatory particles bind to one or both ends of the 20 S proteasome cylinder, forming 26 S and 30 S proteasomes respectively. These regulatory complexes are able to bind proteins marked as proteasome substrates by prior conjugation with polyubiquitin chains, and initiate their unfolding and translocation into the proteolytic chamber of the 20 S proteasome, where they are broken down into peptides of 3-25 amino acids. The polyubiquitin tag is removed from the substrate protein by the deubiquitinating activity of the 19 S regulator complex. Under conditions of an intensified immune response, many eukaryotic cells adapt by replacing standard 20 S proteasomes with immuno-proteasomes and/or generating the proteasome activator complex, PA28. Both of these adaptations change the protein-breakdown process for optimized generation of antigenic peptide epitopes that are presented by the class I MHCs. Hybrid proteasomes (19 S regulator-20 S proteasome-PA28) may have a special function during the immune response. The functions of other proteasome accessory complexes, such as PA200 and PI31 are still under investigation.

Animals↗
PubMed2003

Anatomically based guidelines for systematic investigation of the central somatosensory system and their application to a spinocerebellar ataxia type 2 (SCA2) patient.

Dysfunctions of the somatosensory system are among the clinical signs that characterize a variety of polyglutamine or CAG-repeat diseases. Deficits within this system may hinder the perception of potential threats, be detrimental to somatomotor functions, and result in uncoordinated movements, ataxia, and falls. Despite the considerable clinical relevance of such deficits, however, no systematic pathoanatomical studies of the central somatosensory system in polyglutamine diseases are currently available. The present paper has two goals: (1) recommendation of an economical tissue sampling method and optimized histological processing of this tissue to allow rapid and reliable evaluation of the structural integrity of all known relay stations and interconnecting fibre tracts within this complex system, and (2) the proposal of guidelines for a rapid and detailed pathoanatomical investigative procedure of the human central somatosensory system. In so doing, we draw on the current state of neuroanatomic research and apply the methods and guidelines proposed here to a 25-year-old female patient with spinocerebellar ataxia type 2 (SCA2). The use of 100 microm serial sections through the SCA2 patient's central somatosensory components showed that obvious neuronal loss occurred in nearly all of the relay stations of this system (Clarke's column; cuneate, external cuneate and gracile nuclei; spinal, principal and mesencephalic trigeminal nuclei; ventral posterior lateral and ventral posterior medial nuclei of the thalamus), whereas the majority of interconnecting fibre tracts (dorsal spinocerebellar tract; cuneate and gracile fascicles; medial lemniscus; spinal trigeminal tract, trigeminal nerve and mesencephalic trigeminal tract) displayed signs of atrophy accompanied by demyelinization. These pathological findings suffice to explain the patient's impaired senses of vibration, position and temperature. Moreover, together with the lesions seen in the motor cerebellothalamocortical feedback loop (pontine nuclei, deep cerebellar nuclei and cerebellar cortex, ventral lateral nucleus of the thalamus), they also account for the somatomotor deficits that were observed in the young woman (gait, stance, and limb ataxia, falls, and impaired writing). In proposing these new guidelines, we hope to enable others to study the hitherto unknown morphological counterparts of somatosensory dysfunctions in additional CAG-repeat disease patients.

Adult↗
PubMed2003

Nucleic acid technology screening of Australian blood donors for hepatitis C and human immunodeficiency virus-1 RNA: comparison of two high-throughput testing strategies.

BACKGROUND AND OBJECTIVES: The aim of this study was to compare the performance of two high-throughput strategies for hepatitis C virus (HCV) and human immunodeficiency virus-1 (HIV-1) RNA nucleic acid technology (NAT) screening in a volunteer blood-donor population. MATERIALS AND METHODS: The semiautomated Chiron Procleix HIV-1/HCV transcription mediated amplification (TMA) assay was used to screen 1 439 765 donations in two different testing configurations. Three sites (termed PDT sites) performed a mixture of individual donation (ID) and minipool (MP) testing, where 1 113 288 donations were screened as pools of 24 and an additional 32 003 donations were screened in ID format. A further two sites (termed SDT sites) screened 294 474 donations exclusively in ID format. RESULTS: A significantly higher proportion of initial NAT reactives that failed to react on follow-up testing [termed non-repeatably reactive (NRR)] was observed for ID testing at SDT sites than at PDT sites (0.082 vs. 0.047%: P < 0.01). Within the PDT sites, however, there was no significant difference between the NRR rate for MP or ID samples (0.037 vs. 0.047%; not significant). There was a significant difference in failed run rates between PDT and SDT sites (P < 0.01), with PDT sites having a higher run failure rate owing to non-amplification of the internal control. The PDT sites also had a significantly higher overall invalid sample rate. However, the invalid sample rate, specifically caused by known equipment failure, was significantly higher in the SDT sites, possibly attributable to greater usage (P < 0.0001). Four HCV NAT-positive/antibody-negative samples were identified in the course of the study. CONCLUSIONS: The comparison of the performance of PDT with SDT sites identified only minor differences that did not adversely impact on the timely release of blood products. Although both ID and MP strategies showed excellent specificity, irrespective of site configuration, the significantly increased NRR rate, observed exclusively for ID testing performed at SDT sites, indicates a potential for contamination that may limit the number of samples that can optimally be processed using ID testing. The performance data for ID testing in particular should serve as a useful benchmark for evaluating candidate NAT systems that are fully automated.

Australia↗
PubMed2004

Cumulative sum control charts for assessing performance in arterial surgery.

BACKGROUND: The Melbourne Vascular Surgical Association (Melbourne, Australia) undertakes surveillance of mortality following aortic aneurysm surgery, patency at discharge following infrainguinal bypass and stroke and death following carotid endarterectomy. Quality improvement protocol employing the Deming cycle requires that the system for performing surgery first be analysed and optimized. Then process and outcome data are collected and these data require careful analysis. There must be a mechanism so that the causes of unsatisfactory outcomes can be determined and a good feedback mechanism must exist so that good performance is acknowledged and unsatisfactory performance corrected. A simple method for analysing these data that detects changes in average outcome rates is available using cumulative sum statistical control charts. METHODS: Data have been analysed both retrospectively from 1999 to 2001, and prospectively during 2002 using cumulative sum control methods. A pathway to deal with control chart signals has been developed. RESULTS: The standard of arterial surgery in Victoria, Australia, is high. In one case a safe and satisfactory outcome was achieved by following the pathway developed by the audit committee. CONCLUSION: Cumulative sum control charts are a simple and effective tool for the identification of variations in performance standards in arterial surgery. The establishment of a pathway to manage problem performance is a vital part of audit activity.

Algorithms↗
PubMed2001

Allogeneic transplantation across the HLA barriers.

In high-risk acute leukemia patients, a 10-fold increase in the dose of extensively T-cell-depleted hematopoietic stem cells ensures sustained full-donor engraftment of one-haplotype-mismatched transplants without graft-vs.-host disease. Since our first successful pilot study, which exploited the principle of a megadose stem cell transplant, our efforts have concentrated on developing new conditioning regimens, optimizing graft processing and improving the post-transplant immunologic recovery. The results so far achieved in more than 100 high-risk acute leukemia patients show that haploidentical transplantation is now a clinical reality. Because virtually all patients in need of a hematopoietic stem cell transplant have a full-haplotype-mismatched family donor, a T-cell-depleted mismatched transplant can be offered with curative intent, thus extending allogeneic transplantation procedures to virtually all candidates.

Acute Disease↗
PubMed2001

Predictive value of T-wave morphology variables and QT dispersion for postmyocardial infarction risk assessment.

Different attempts have been made to use the 12-lead surface electrocardiogram (ECG) for risk stratification of patients prone to sudden cardiac death. Among others, QT dispersion (QTd) has been proposed as a simple risk marker, eg, in patients postmyocardial infarction (MI). To overcome the methodological limitations of QTd, novel T-wave morphology variables have been recently developed based on technologies that better quantify the substrate of a pathologically changed repolarization. In 280 post-MI patients with 27 events (death or nonfatal sustained ventricular tachycardia/ventricular fibrillation) during long-term follow-up (32 +/- 10 months), a 12-lead ECG was recorded before discharge and converted into a digital format. The prognostic value of digitally measured QTd and other conventional variables, and that of novel ECG variables of T-wave loop morphology was assessed. The latter included fully automatic and reproducible analysis of variables defining spatial and temporal T-wave variation as well as its wavefront direction. Among the 5 variables studied, the total cosine R to T (TCRT--describing the global angle between repolarization and depolarization orientations) and the T-wave loop dispersion were univariately associated (P = .0002 and P < .002) with events. Comparison of Kaplan Meier curves for patient strata above and below the median confirmed the strong discrimination of risk by TCRT and T-wave loop dispersion values (P < .003 and P < .001). On Cox regression analysis entering other univariately predictive risk stratifiers including age, left ventricular ejection fraction, heart rate, reperfusion therapy, beta adrenergic blocker treatment, and SDNN from Holter, TCRT (P < .03) yielded independent predictive value while T-wave loop dispersion was of borderline independence (P = .064). Heart rate (P < .02), left ventricular ejection fraction (P < .02), and reperfusion therapy (P <.02) also remained in the final model. In contrast, none of the conventional variables of repolarization dispersion including QTd and rate-corrected QTd revealed prognostic value on univariate or Kaplan Meier analysis despite optimized digital processing techniques. Computerized analysis of T-wave loop morphology from the 12-lead resting ECG permits independent assessment of post-MI risk and should replace the poorly conceptualized measurement of QTd.

Death, Sudden, Cardiac↗
PubMed2001

[Measurement of the outcome quality as beginning of total quality management in otorhinolaryngology].

BACKGROUND: The last years are characterized by a change of paradigms in the evaluation of medical therapeutical strategies. The term quality of life (QoL) has been established in oncology and could be demonstrated as a subject of highly qualified investigations which were published during the last years. An extendend quality management is correlated with the possibility of cost-effectiveness measurement and arrangement in a time characterized by decreasing financial resources of the hospitals and university departments. The experiences in the field of quality analysis could offer precious tools to optimize structures, processes and results of treatments. This aim is strongly supported by the expected law "Gesundheitsreform 2000". METHOD AND RESULTS: Therefore reliable, valid tools are needed to calculate the effects of therapies. The combination of global and specific questionnaires include the possibility to compare oncologic data of different entities of malignomas. A couple of questionnaires in otorhinolaryngology were developed in the last decade involving the fields of malignomas of the upper aerodigestive tract, rhinosinusitis etc. CONCLUSIONS: Ishikawa, the founder of "Total Quality Management" and of the "Quality Circ", pointed out the high importance of customer satisfaction. Whereas the patient is in the mid point of medical treatment there are hardly any investigations about customer satisfaction published. Therefore it is necessary to develop and establish validated tools for the measurement of quality dimensions. The short, middle and long-lasting effects of a treatment could be calculated by quality of life measurements. The QoL is here of very strong importance, especially since economic aspects are included.

Germany↗
PubMed2001

[RecDate - an IT-solution for the documentation and quality management of reproductive medicine].

OBJECTIVES: The aim of this paper was to describe the possible use of the software RecDate für documentation and Quality Management in Reproductive Medicine. MATERIAL AND METHODS: RecDate was programmed using the data base program Filemaker Pro. The functions and potentials of RecDate were analyzed. RESULTS: RecDate enables the collection, documentation and evaluation of data from Reproductive Medicine and also functions as a hospital management tool. CONCLUSIONS: The present status of Reproductive Medicine can be described by the use of RecDate in IVF-clinics, which is important for consulting and treatment of couples, for the quality of public enlightenment and for optimizing the processes in daily routine.

Computer Communication Networks↗
PubMed1988

Revascularization of nerve grafts: an experimental study.

The time course of revascularization of grafted nerves, and the possible dependence of this revascularization on the length of the graft are two related questions that are addressed. Survival of Schwann cells in the nerve graft and a timely revascularization must be seen as a precondition for an optimal regeneration process. The revascularization process after different postoperative intervals is demonstrated in the sciatic nerve of rabbits by the use of microangiography, with Roentgen-positive water-soluble contrast medium. The third postoperative day is the earliest point in time for revascularization of the autologous graft from surrounding tissues. On the fourth postoperative day, a hyperemia with extension to all sides of the intraneural vessel system exists that still persists on the fifth and sixth days. In one experimental group, revascularization was allowed to occur only in a longitudinal direction. Revascularization under these conditions proved to be poor, slow, and obviously dependent on the length of the graft. Survival and subsequent function of free autologous nerve grafts may depend on the diameter of the grafts and the quality of the recipient site, but not on the length of the grafts, when timely revascularization from the surrounding tissues is present.

Animals↗
PubMed1998

[Dosage monitoring as a quality control instrument in digital radiography].

PURPOSE: Automatic image processing procedures ensure a constant image quality. Overexposed images constitute a danger zone on account of a subjectively better image appearance (improved signal-to-noise ratio). We have examined the software "Dose-Monitoring" both for the identification of false exposures and as a quality control tool. MATERIALS AND METHODS: Firstly the correlation between dose and present IgM (mean grey tone from the crude histogram of a 12-bit image) was examined by exposing phantoms. A further-reaching comparison of the present IgM values of some MTRAs with the department average (nominal IgM) should detect tendencies for over- and underexposure. Finally a dose reduction in 12 forms of X-ray examination was evaluated with regard to IgM course controls (median IgM). RESULTS: A high correlation (0.987) between dose and mean grey tone (IgM). In some MRTAs tendency for over-/underexposure was detected. The dose reduction of defined types of X-ray examination lead to a trend to lower mean IgM values. DISCUSSION: Numerous factors have an influence on the IgM value thus making its evaluation difficult, even so it is a suitable parameter for uncovering tendencies to incorrect exposure and for identifying processes requiring optimization. CONCLUSIONS: The value of this tool lies in the quality assurance of dose fluctuations and a possible dose reduction.

Humans↗
PubMed1995

[Therapy with immunoglobulins in neurologic autoimmune diseases. Indications and mechanism of action].

Intravenous 7S-immunoglobulins (IVIg) are made of intact human IgG from pooled plasma by using cold alcohol fractionation followed by further purification steps to remove complement-activating material. The half-life of IVIg in vivo is approximately 3 weeks. Favourable effects were reported in patients with myositis and multifocal motor neuropathy who did not respond to established immunosuppressive therapies, and in Guillain-Barre-Syndrome and chronic inflammatory demyelinating polyneuropathy. No definite recommendation can presently be made concerning their use in other neuromuscular disorders and in multiple sclerosis where the results of ongoing and future controlled studies have to be awaited. Some of the possible mechanisms of immunoglobulin efficacy have been delineated in animal models and tissue culture: anti-idiotypic suppression, down-regulation of B- and T-cell activation, blockade of Fc receptors on phagocytic cells, neutralisation of superantigen and complement mediated effects, down-regulation of cytokine production and neutralisation of cytokines. Few side effects have been reported to date. However, treatment is expensive when compared with established immunosuppressive therapies. The main risk consists of the transmission of infectious agents that can only be excluded if the manufacturing process is optimal. A broad and uncontrolled use of immunoglobulins in the treatment of neurologic disorders is discouraged.

Autoimmune Diseases↗
PubMed1991

[Digital luminescence radiography (DLR) for skeletal diagnosis in traumatology].

170 patients who had suffered trauma to bones or soft tissues were examined by a digital and a conventional film/screen technique. In addition to "standard" and edge-enhanced images, post-processing was carried out and compared with conventional radiographs. Four radiologists and two surgeons evaluated the compacta, spongiosa, soft tissues, fractures and osteo-synthetic materials as shown on the two systems. The "standard" digital images are inferior to film images, but edge-enhanced images showed definite advantages for demonstrating soft tissues. Evaluation of osteo-synthetic material is limited by the creation of artifacts. Recognition of detail can be significantly improved by using post-processing with optimized parameters.

Adolescent↗
PubMed2002

The implementation of a surgical antibiotic prophylaxis program: the pivotal contribution of the hospital pharmacy.

BACKGROUND: Although surgical site infection rates have decreased with the prophylactic use of antibiotics, the inappropriateness of surgical antibiotic prophylaxis is still a worldwide problem. Various strategies have been used to address this problem. This study describes the implementation of a perioperative antibiotic prophylaxis protocol that emphasizes the contribution of the pharmacist. METHODS: A descriptive study design was used to evaluate the impact of the protocol on the appropriateness of prophylaxis in a private university hospital. The surgical antibiotic prophylaxis of all surgeries was evaluated for 1 month before and 1 month after the implementation of the protocol. RESULTS: The appropriateness of the indication for prophylaxis rose from 56.4% to 100% and that of the postoperative maintenance prophylactic antibiotics rose from 21.9% to 95.7%. The cost of the perioperative antibiotic prophylaxis per surgery decreased 40.5%. CONCLUSION: The implementation of a cost-effective perioperative antibiotic prophylaxis protocol was the result of a multidisciplinary effort. The hospital pharmacist participated in education activities as part of the discussion groups on the perioperative antibiotic prophylaxis protocol that involved all participants and in managerial actions that optimized the process of ordering, dispensing, administering, and documenting the perioperative antibiotic prophylaxis.

Adolescent↗
PubMed2002

Oscillatory brain states and learning: Impact of hippocampal theta-contingent training.

Eyeblink classical conditioning is a relatively simple form of associative learning that has become an invaluable tool in our understanding of the neural mechanisms of learning. When studying rabbits in this paradigm, we observed a dramatic modification of learning rate by conducting training during episodes of either hippocampal theta or hippocampal non-theta activity as determined by on-line slow-wave spectral analysis. Specifically, if animals were given trials only when a computer analysis verified a predominance of slow-wave oscillations at theta frequencies (3-8 Hz), they learned in half as many trials as animals trained during non-theta hippocampal activity (58 vs. 115). This finding provides important evidence from awake, behaving animals that supports recent advances in our knowledge of (i) brain sites and neurobiological mechanisms of learning and memory, specifically hippocampus and theta oscillations, (ii) the biological plausibility of current models of hippocampal function that posit important roles for oscillatory potentials, and (iii) the design of interfaces between biological and cybernetic (electronic) systems that can optimize cognitive processes and performance.

Acoustic Stimulation↗
PubMed2006

Veela defines a molecular link between Cryptochrome and Timeless in the light-input pathway to Drosophila's circadian clock.

Organisms use the daily cycles of light and darkness to synchronize their internal circadian clocks with the environment. Because they optimize physiological processes and behavior, properly synchronized circadian clocks are thought to be important for the overall fitness. In Drosophila melanogaster, the circadian clock is synchronized with the natural environment by light-dependent degradation of the clock protein Timeless, mediated by the blue-light photoreceptor Cryptochrome (Cry). Here we report identification of a genetic variant, Veela, which severely disrupts this process, because these genetically altered flies maintain behavioral and molecular rhythmicity under constant-light conditions that usually stop the clock. We show that the Veela strain carries a natural timeless allele (ls-tim), which encodes a less-light-sensitive form of Timeless in combination with a mutant variant of the F-box protein Jetlag. However, neither the ls-tim nor the jetlag genetic variant alone is sufficient to disrupt light input into the central pacemaker. We show a strong interaction between Veela and cryptochrome genetic variants, demonstrating that the Jetlag, Timeless, and Cry proteins function in the same pathway. Veela also reveals a function for the two natural variants of timeless, which differ in their sensitivity to light. In combination with the complex array of retinal and extraretinal photoreceptors known to signal light to the pacemaker, this previously undescribed molecular component of photic sensitivity mediated by the two Timeless proteins reveals that an unexpectedly rich complexity underlies modulation of this process.

Alleles↗
PubMed2003

Helical Lévy walks: adjusting searching statistics to resource availability in microzooplankton.

The searching trajectories of different animals can be described with a broad class of flight length (lj) distributions with P(lj) = lj-mu. Theoretical studies have shown that changes in these distributions (i.e., different mu values) are key to optimizing the long-term encounter statistics under certain searcher-resource scenarios. In particular, they predict the advantage of Lévy searching (mu approximately 2) over Brownian motion (mu > or = 3) for low-prey-density scenarios. Here, we present experimental evidence of predicted optimal changes in the flight-time distribution of a predator's walk in response to gradual density changes of its moving prey. Flight times of the dinoflagellate Oxyrrhis marina switched from an exponential to an inverse square power-law distribution when the prey (Rhodomonas sp.) decreased in abundance. Concomitantly, amplitude and frequency of the short-term helical path increased. The specific biological mechanisms involved in these searching behavioral changes are discussed. We suggest that, in a three-dimensional environment, a stronger helical component combined with a Lévy walk searching strategy enhances predator's encounter rates. Our results support the idea of universality of the statistical laws in optimal searching processes despite variations in the biological details of the organisms.

Animals↗