Rapid Reorganization of an Academic Infectious Diseases Program During the Coronavirus Disease 2019 Pandemic in Detroit: A Novel Unit-based Group Rounding Model.

The surge of coronavirus disease 2019 (COVID-19) hospitalizations at our 877-bed quaternary care hospital in Detroit led to an emergent demand for Infectious Diseases (ID) consultations. The traditional 1-on-1 consultation model was untenable. Therefore, we rapidly restructured our ID division to provide effective consultative services. We implemented a novel unit-based group rounds model that focused on delivering key updates to teams and providing unit-wide consultations simultaneously to all team members. Effectiveness of the program was studied using Likert-scale survey data. The survey captured data from the first month of the Detroit COVID-19 pandemic. During this period there were approximately 950 patients hospitalized for treatment of COVID-19. The survey of trainees and faculty reported an overall 95% positive response to delivery of information, new knowledge acquisition, and provider confidence in the care of COVID-19 patients. This showed that the unit-based consult model is a sustainable effort to provide care during epidemics.

Clinical characteristics and predictors of survival in adults with coronavirus disease 2019 receiving tocilizumab.

Coronavirus disease 2019 (COVID-19) can progress to cytokine storm that is associated with organ dysfunction and death. The purpose of the present study is to determine clinical characteristics associated with 28 day in-hospital survival in patients with coronavirus disease 2019 (COVID-19) that received tocilizumab. This was a retrospective observational cohort study conducted at a five hospital health system in Michigan, United States. Adult patients with confirmed COVID-19 that were admitted to the hospital and received tocilizumab for cytokine storm from March 1, 2020 through April 3, 2020 were included. Patients were grouped into survivors and non-survivors based on 28 day in-hospital mortality. Study day 0 was defined as the day tocilizumab was administered. Factors independently associated with in-hospital survival at 28 days after tocilizumab administration were assessed. Epidemiologic, demographic, laboratory, prognostic scores, treatment, and outcome data were collected and analyzed. Clinical response was collected and defined as a decline of two levels on a six-point ordinal scale of clinical status or discharged alive from the hospital. Of the 81 patients included, the median age was 64 (58-71) years and 56 (69.1%) were male. The 28 day in-hospital mortality was 43.2%. There were 46 (56.8%) patients in the survivors and 35 (43.2%) in the non-survivors group. On study day 0 no differences were noted in demographics, clinical characteristics, severity of illness scores, or treatments received between survivors and non-survivors. C-reactive protein was significantly higher in the non-survivors compared to survivors. Compared to non-survivors, recipients of tocilizumab within 12 days of symptom onset was independently associated with survival (adjusted OR: 0.296, 95% CI: 0.098-0.889). SOFA score ≥8 on day 0 was independently associated with mortality (adjusted OR: 2.842, 95% CI: 1.042-7.753). Clinical response occurred more commonly in survivors than non-survivors (80.4% vs. 5.7%; p < 0.001). Improvements in the six-point ordinal scale and SOFA score were observed in survivors after tocilizumab. Early receipt of tocilizumab in patients with severe COVID-19 was an independent predictor for in-hospital survival at 28 days.

Epidemiology of orthodontic treatment need in southwestern Ethiopian children: a cross sectional study using the index of orthodontic treatment need.

BACKGROUND: The planning of orthodontic treatment within a public health system requires information on the orthodontic treatment needs of the population. It is important to have epidemiological data to estimate the total need for orthodontic care in any region. The present study aimed to determine the orthodontic treatment need in 12 years old Southwestern Ethiopian children. METHODS: The institution-based cross-sectional study was conducted which involved 347 twelve years old school children randomly selected from seven different public schools in Jimma Town, Southwestern Ethiopia. A structured interview and clinical examination were used to assess the subjects. One examiner used Dental Health Component (DHC) and Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) to estimate the treatment need. Descriptive statistics and chi-square tests were used for data analysis with statistical significance set at P < 0.05. RESULTS: According to the DHC of IOTN, almost half of the subjects in the sample were in moderate to the great need for orthodontic treatment. About 15% of the children had a great need for orthodontic treatment based on IOTN-AC. The most prevalent occlusal traits for defining the DHC categorization include increased Overjet (30.8%) and Crowding (23.3%). There was no statistical difference in the distribution of DHC grades and AC scored based on gender. CONCLUSION: This study revealed that the need for orthodontic treatment was high. The percentage of the need for orthodontic treatment is higher in comparison to most of the studies conducted in African regions. Therefore, publicly subsidized orthodontic treatment should be planned and provided to those who are in great need for orthodontic treatment. Besides, awareness about orthodontic treatment should also be considered.

Power input effects on degeneration in prolonged penicillin chemostat cultures: A systems analysis at flux, residual glucose, metabolite, and transcript levels.

In the present work, by performing chemostat experiments at 400 and 600 RPM, two typical power inputs representative of industrial penicillin fermentation (P/V, 1.00 kW/m3 in more remote zones and 3.83 kW/m3 in the vicinity of the impellers, respectively) were scaled-down to bench-scale bioreactors. It was found that at 400 RPM applied in prolonged glucose-limited chemostat cultures, the previously reported degeneration of penicillin production using an industrial Penicillium chrysogenum strain was virtually absent. To investigate this, the cellular response was studied at flux (stoichiometry), residual glucose, intracellular metabolite and transcript levels. At 600 RPM, 20% more cell lysis was observed and the increased degeneration of penicillin production was accompanied by a 22% larger ATP gap and an unexpected 20-fold decrease in the residual glucose concentration (Cs,out ). At the same time, the biomass specific glucose consumption rate (qs ) did not change but the intracellular glucose concentration was about sixfold higher, which indicates a change to a higher affinity glucose transporter at 600 RPM. In addition, power input differences cause differences in the diffusion rates of glucose and the calculated Batchelor diffusion length scale suggests the presence of a glucose diffusion layer at the glucose transporting parts of the hyphae, which was further substantiated by a simple proposed glucose diffusion-uptake model. By analysis of calculated mass action ratios (MARs) and energy consumption, it indicated that at 600 RPM glucose sensing and signal transduction in response to the low Cs,out appear to trigger a gluconeogenic type of metabolic flux rearrangement, a futile cycle through the pentose phosphate pathway (PPP) and a declining redox state of the cytosol. In support of the change in glucose transport and degeneration of penicillin production at 600 RPM, the transcript levels of the putative high-affinity glucose/hexose transporter genes Pc12g02880 and Pc06g01340 increased 3.5- and 3.3-fold, respectively, and those of the pcbC gene encoding isopenicillin N-synthetase (IPNS) were more than twofold lower in the time range of 100-200 hr of the chemostat cultures. Summarizing, changes at power input have unexpected effects on degeneration and glucose transport, and result in significant metabolic rearrangements. These findings are relevant for the industrial production of penicillin, and other fermentations with filamentous microorganisms.

A 9-pool metabolic structured kinetic model describing days to seconds dynamics of growth and product formation by Penicillium chrysogenum.

A powerful approach for the optimization of industrial bioprocesses is to perform detailed simulations integrating large-scale computational fluid dynamics (CFD) and cellular reaction dynamics (CRD). However, complex metabolic kinetic models containing a large number of equations pose formidable challenges in CFD-CRD coupling and computation time afterward. This necessitates to formulate a relatively simple but yet representative model structure. Such a kinetic model should be able to reproduce metabolic responses for short-term (mixing time scale of tens of seconds) and long-term (fed-batch cultivation of hours/days) dynamics in industrial bioprocesses. In this paper, we used Penicillium chrysogenum as a model system and developed a metabolically structured kinetic model for growth and production. By lumping the most important intracellular metabolites in 5 pools and 4 intracellular enzyme pools, linked by 10 reactions, we succeeded in maintaining the model structure relatively simple, while providing informative insight into the state of the organism. The performance of this 9-pool model was validated with a periodic glucose feast-famine cycle experiment at the minute time scale. Comparison of this model and a reported black box model for this strain shows the necessity of employing a structured model under feast-famine conditions. This proposed model provides deeper insight into the in vivo kinetics and, most importantly, can be straightforwardly integrated into a computational fluid dynamic framework for simulating complete fermentation performance and cell population dynamics in large scale and small scale fermentors. Biotechnol. Bioeng. 2017;114: 1733-1743. © 2017 Wiley Periodicals, Inc.

In vivo kinetic analysis of the penicillin biosynthesis pathway using PAA stimulus response experiments.

In this study we combined experimentation with mathematical modeling to unravel the in vivo kinetic properties of the enzymes and transporters of the penicillin biosynthesis pathway in a high yielding Penicillium chrysogenum strain. The experiment consisted of a step response experiment with the side chain precursor phenyl acetic acid (PAA) in a glucose-limited chemostat. The metabolite data showed that in the absence of PAA all penicillin pathway enzymes were expressed, leading to the production of a significant amount of 6-aminopenicillanic acid (6APA) as end product. After the stepwise perturbation with PAA, the pathway produced PenG within seconds. From the extra- and intracellular metabolite measurements, hypotheses for the secretion mechanisms of penicillin pathway metabolites were derived. A dynamic model of the penicillin biosynthesis pathway was then constructed that included the formation and transport over the cytoplasmic membrane of pathway intermediates, PAA and the product penicillin-G (PenG). The model parameters and changes in the enzyme levels of the penicillin biosynthesis pathway under in vivo conditions were simultaneously estimated using experimental data obtained at three different timescales (seconds, minutes, hours). The model was applied to determine changes in the penicillin pathway enzymes in time, calculate fluxes and analyze the flux control of the pathway. This led to a reassessment of the in vivo behavior of the pathway enzymes and in particular Acyl-CoA:Isopenicillin N Acyltransferase (AT).

Resolving phenylalanine metabolism sheds light on natural synthesis of penicillin G in Penicillium chrysogenum.

The industrial production of penicillin G by Penicillium chrysogenum requires the supplementation of the growth medium with the side chain precursor phenylacetate. The growth of P. chrysogenum with phenylalanine as the sole nitrogen source resulted in the extracellular production of phenylacetate and penicillin G. To analyze this natural pathway for penicillin G production, chemostat cultures were switched to [U-(13)C]phenylalanine as the nitrogen source. The quantification and modeling of the dynamics of labeled metabolites indicated that phenylalanine was (i) incorporated in nascent protein, (ii) transaminated to phenylpyruvate and further converted by oxidation or by decarboxylation, and (iii) hydroxylated to tyrosine and subsequently metabolized via the homogentisate pathway. The involvement of the homogentisate pathway was supported by the comparative transcriptome analysis of P. chrysogenum cultures grown with phenylalanine and with (NH(4))(2)SO(4) as the nitrogen source. This transcriptome analysis also enabled the identification of two putative 2-oxo acid decarboxylase genes (Pc13g9300 and Pc18g01490). cDNAs of both genes were cloned and expressed in the 2-oxo-acid-decarboxylase-free Saccharomyces cerevisiae strain CEN.PK711-7C (pdc1 pdc5 pdc6Δ aro10Δ thi3Δ). The introduction of Pc13g09300 restored the growth of this S. cerevisiae mutant on glucose and phenylalanine, thereby demonstrating that Pc13g09300 encodes a dual-substrate pyruvate and phenylpyruvate decarboxylase, which plays a key role in an Ehrlich-type pathway for the production of phenylacetate in P. chrysogenum. These results provide a basis for the metabolic engineering of P. chrysogenum for the production of the penicillin G side chain precursor phenylacetate.

Determination of δ-[L-α-aminoadipyl]-L-cysteinyl-D-valine in cell extracts of Penicillium chrysogenum using ion pair-RP-UPLC-MS/MS.

δ-[L-α-Aminoadipyl]-L-cysteinyl-D-valine (ACV) is a key intermediate in the biosynthesis pathway of penicillins and cephalosporins. Therefore, the accurate quantification of ACV is relevant, e.g. for kinetic studies on the production of these ß-lactam antibiotics. However, accurate quantification of ACV is a challenge, because it is an active thiol compound which, upon exposure to air, can easily react with other thiol compounds to form oxidized disulfides. We have found that, during exposure to air, the oxidation of ACV occurs both in aqueous standard solutions as well as in biological samples. Qualitative and quantitative determinations of ACV and the oxidized dimer bis-δ-[L-α-aminoadipyl]-L-cysteinyl-D-valine have been carried out using ion pair reversed-phase ultra high-performance liquid chromatography, hyphenated with tandem mass spectrometry (IP-RP-UPLC-MS/MS) as the analytical platform. We show that by application of tris(2-carboxy-ethyl)phosphine hydrochloride (TCEP) as the reducing reagent, the total amount of ACV can be determined, while using maleimide as derivatizing reagent enables to quantify the free reduced form only.

Improving Efficiency on a Pediatric Hospital Medicine Service With Schedule-Based Family-Centered Rounds.

BACKGROUND AND OBJECTIVES: Inconsistencies in the timing and process of family-centered rounds can contribute to inefficiencies in patient care, inconsistent nursing participation, and variable end times. Through the implementation of schedule-based rounds, our aims were to (1) start 90% of rounds encounters within 30 minutes of the scheduled time, (2) increase nursing presence from 79% to >90%, and (3) increase the percentage of rounds completed by 11:20 am from 0% to 80% within 1 year. METHODS: We used quality improvement methods to implement and evaluate a scheduled rounds process on a pediatric hospital medicine service at a university-affiliated children's hospital. Interventions included customization of an electronic health record-linked scheduling tool, daily schedule management by the senior resident, real-time rounds notification to nurses, improved education on rounding expectations, streamlined rounding workflow, and family notification of rounding time. Data were collected daily and run charts were used to track metrics. RESULTS: One year after implementation, a median of 96% of rounds encounters occurred within 30 minutes of scheduled rounding time, nursing presence increased from a median of 79% to 94%, and the percentage of rounds completed by 11:20 am increased from a median of 0% to 86%. Rounds end times were later with a higher patient census. CONCLUSIONS: We improved the efficiency of our rounding workflow and bedside nursing presence through a scheduled rounds process facilitated by an electronic health record-linked scheduling tool.

Effect of a urine culture stewardship initiative on urine culture utilization and catheter-associated urinary tract infections in intensive care units.

OBJECTIVE: Urine cultures have poor specificity for catheter-associated urinary tract infections (CAUTIs). We evaluated the effect of a urine-culture stewardship program on urine culture utilization and CAUTI in adult intensive care units (ICUs). DESIGN: A quasi-interventional study was performed from 2015 to 2017. SETTING AND PATIENTS: The study cohort comprised 21,367 patients admitted to the ICU at a teaching hospital. INTERVENTION: The urine culture stewardship program included monthly 1-hour discussions with ICU house staff emphasizing avoidance of "pan-culture" for sepsis workup and obtaining urine culture only if a urinary source of sepsis is suspected. The urine culture utilization rate metric (UCUR; ie, no. urine cultueres/catheter days ×100) was utilized to measure the effect. Monthly UCUR, catheter utilization ratio (CUR), and CAUTI rate were reported on an interactive quality dashboard. To ensure safety, catheterized ICU patients (2015-2016) were evaluated for 30-day readmission for UTI. Time-series data and relationships were analyzed using Spearman correlation coefficients and regression analysis. RESULTS: Urine culture utilization decreased from 3,081 in 2015 to 2,158 in 2016 to 1,218 in 2017. CAUTIs decreased from 78 in 2015 to 60 in 2016 and 28 in 2017. Regression analysis over time showed significant decreases in UCUR (r, 0.917; P < .0001) and CAUTI rate (r, 0.657; P < .0001). The co-correlation between UCUR and CAUTI rate was (r, 0.625; P < .0001) compared to CUR and CAUTI rate (r, 0.523; P = .004). None of these patients was readmitted with a CAUTI. CONCLUSIONS: Urine culture stewardship program was effective and safe in reducing UC overutilization and was correlated with a decrease in CAUTIs. Addition of urine-culture stewardship to standard best practices could reduce CAUTI in ICUs.

Role of Texting as a Source of Cognitive Burden in a Pediatric Cardiovascular ICU.

OBJECTIVES: To characterize frontline provider perception of clinical text messaging and quantify clinical texting data in a pediatric cardiovascular ICU (CICU). METHODS: This is a mixed-methods, retrospective single center study. A survey of frontline CICU providers (pediatric fellows, nurse practitioners, and physician assistants) was conducted to assess attitudes characterizing text messaging on cognitive burden. Text messaging data were abstracted and quantified between January 29, 2020, and April 18, 2020, and the patterns of text messages were analyzed per shift and by provider. RESULTS: The survey was completed by 33 of 39 providers (85%). Out of responders, 78% indicated that clinical text messaging frequently or very frequently disrupts critical thinking and workflow. They also felt that the burden of messages was worse during the night shift. Through abstraction, 31 926 text messages were identified. A median of 15 (interquartile range: 12-19) messages per hour were received. A median of 5 messages were received per hour per provider during the day shift and 6 during the night shift. From the entire study period, there were total 2 hours of high-frequency texting (≥15 texts per hour) during the day shift and 68 hours during the night shift. CONCLUSION: In our study, providers in the CICU received a large number of texts with a disproportionate burden during the night shift. Text messages are a potential source of cognitive overload for providers. Optimization of text messaging may be needed to mitigate cognitive burden for frontline providers.

Current Practices and Perspectives on Peer Observation and Feedback: A National Survey.

OBJECTIVE: Peer observation and feedback (POF) is the direct observation of an activity performed by a colleague followed by feedback with the goal of improved performance and professional development. Although well described in the education literature, the use of POF as a tool for development beyond teaching skills has not been explored. We aimed to characterize the practice of POF among pediatric hospitalists to explore the perceived benefits and barriers and to identify preferences regarding POF. METHODS: We developed a 14-item cross-sectional survey regarding divisional expectations, personal practice, perceived benefits and barriers, and preferences related to POF. We refined the survey based on expert feedback, cognitive interviews, and pilot testing, distributing the final survey to pediatric hospitalists at 12 institutions across the United States. RESULTS: Of 357 eligible participants, 198 (56%) responded, with 115 (58%) practicing in a freestanding children's hospital. Although 61% had participated in POF, less than one half (42%) reported divisional POF expectation. The most common perceived benefits of POF were identifying areas for improvement (94%) and learning about colleagues' teaching and clinical styles (94%). The greatest perceived barriers were time (51%) and discomfort with receiving feedback from peers (38%), although participation within a POF program reduced perceived barriers. Most (76%) desired formal POF programs focused on improving teaching skills (85%), clinical management (83%), and family-centered rounds (82%). CONCLUSIONS: Although the majority of faculty desired POF, developing a supportive environment and feasible program is challenging. This study provides considerations for improving and designing POF programs.

Comparative performance of different scale-down simulators of substrate gradients in Penicillium chrysogenum cultures: the need of a biological systems response analysis.

In a 54 m3 large-scale penicillin fermentor, the cells experience substrate gradient cycles at the timescales of global mixing time about 20-40 s. Here, we used an intermittent feeding regime (IFR) and a two-compartment reactor (TCR) to mimic these substrate gradients at laboratory-scale continuous cultures. The IFR was applied to simulate substrate dynamics experienced by the cells at full scale at timescales of tens of seconds to minutes (30 s, 3 min and 6 min), while the TCR was designed to simulate substrate gradients at an applied mean residence time (τc) of 6 min. A biological systems analysis of the response of an industrial high-yielding P. chrysogenum strain has been performed in these continuous cultures. Compared to an undisturbed continuous feeding regime in a single reactor, the penicillin productivity (qPenG ) was reduced in all scale-down simulators. The dynamic metabolomics data indicated that in the IFRs, the cells accumulated high levels of the central metabolites during the feast phase to actively cope with external substrate deprivation during the famine phase. In contrast, in the TCR system, the storage pool (e.g. mannitol and arabitol) constituted a large contribution of carbon supply in the non-feed compartment. Further, transcript analysis revealed that all scale-down simulators gave different expression levels of the glucose/hexose transporter genes and the penicillin gene clusters. The results showed that qPenG did not correlate well with exposure to the substrate regimes (excess, limitation and starvation), but there was a clear inverse relation between qPenG and the intracellular glucose level.

A peek into the future of radiology using big data applications.

Big data is extremely large amount of data which is available in the radiology department. Big data is identified by four Vs - Volume, Velocity, Variety, and Veracity. By applying different algorithmic tools and converting raw data to transformed data in such large datasets, there is a possibility of understanding and using radiology data for gaining new knowledge and insights. Big data analytics consists of 6Cs - Connection, Cloud, Cyber, Content, Community, and Customization. The global technological prowess and per-capita capacity to save digital information has roughly doubled every 40 months since the 1980's. By using big data, the planning and implementation of radiological procedures in radiology departments can be given a great boost. Potential applications of big data in the future are scheduling of scans, creating patient-specific personalized scanning protocols, radiologist decision support, emergency reporting, virtual quality assurance for the radiologist, etc. Targeted use of big data applications can be done for images by supporting the analytic process. Screening software tools designed on big data can be used to highlight a region of interest, such as subtle changes in parenchymal density, solitary pulmonary nodule, or focal hepatic lesions, by plotting its multidimensional anatomy. Following this, we can run more complex applications such as three-dimensional multi planar reconstructions (MPR), volumetric rendering (VR), and curved planar reconstruction, which consume higher system resources on targeted data subsets rather than querying the complete cross-sectional imaging dataset. This pre-emptive selection of dataset can substantially reduce the system requirements such as system memory, server load and provide prompt results. However, a word of caution, "big data should not become "dump data" due to inadequate and poor analysis and non-structured improperly stored data. In the near future, big data can ring in the era of personalized and individualized healthcare.

M30, a novel multifunctional neuroprotective drug with potent iron chelating and brain selective monoamine oxidase-ab inhibitory activity for Parkinson's disease.

Iron and monoamine oxidase activity are increased in brain of Parkinson's disease (PD). They are associated with autoxidation and oxidative deamination of dopamine by MAO resulting in the generation of reactive oxygen species and the onset of oxidative stress to induce neurodegeneration. Iron chelators (desferal, Vk-28 and clioquinol) but not copper chelators have been shown to be neuroprotective in the 6-hydroxydoapmine and MPTP models of Parkinson's disease (PD), as are monoamine oxidase B inhibitors such as selegiline and rasagiline. These findings prompted the development of multifunctional anti PD drugs possessing iron chelating phamacophore of VK-28 and the propargylamine MAO inhibitory activity of rasagiline. M30 is a potent iron chelator, radical scavenger and brain selective irreversible MAO-A and B inhibitor, with little inhibition of peripheral MAO. It has neuroprotective activity in in vitro and in vivo models of PD and unlike selective MAO-B inhibitors it increases brain dopamine, serotonin and noradrenaline. These findings indicate beside its anti PD action, it may also possess antidepressant activity, similar to selective MAO-A and nonselective MAO inhibitors. These properties make it an ideal anti PD drug for which it is being developed.

Green tea catechins as brain-permeable, non toxic iron chelators to "iron out iron" from the brain.

Evidence to link abnormal metal (iron, copper and zinc) metabolism and handling with Parkinson's and Alzheimer's diseases pathology has frequently been reported. The capacity of free iron to enhance and promote the generation of toxic reactive oxygen radicals has been discussed numerous times. Metal chelation has the potential to prevent iron-induced oxidative stress and aggregation of alpha-synuclein and beta-amyloid peptides. The efficacy of iron chelators depends on their ability to penetrate the subcellular compartments and cellular membranes where iron dependent free radicals are generated. Thus, natural, non-toxic, brain permeable neuroprotective drugs, are preferentially advocated for "ironing out iron" from those brain areas where it preferentially accumulates in neurodegenerative diseases. This review will discuss the most recent findings from in vivo and in vitro studies concerning the transitional metal (iron and copper) chelating property of green tea, and its major polyphenol, (-)-epigallocatechin-3-gallate with respect to their potential for the treatment of neurodegenerative diseases.

Involvement of multiple survival signal transduction pathways in the neuroprotective, neurorescue and APP processing activity of rasagiline and its propargyl moiety.

Our recent studies aimed to elucidate the molecular and biochemical mechanism of actions of the novel anti-Parkinson's drug, rasagiline, an irreversible and selective monoamine oxidase (MAO)-B inhibitor and its propargyl moiety, propargylamine. In cell death models induced by serum withdrawal in rat PC12 cells and human SH-SY5Y neuroblastoma cells, both rasagiline and propargylamine exerted neuroprotective and neurorescue activities via multiple survival pathways, including: stimulation of protein kinase C (PKC) phosphorylation; up-regulation of protein and gene levels of PKCalpha, PKCepsilon and the anti-apoptotic Bcl-2, Bcl-xL, and Bcl-w; and up-regulation of the neurotrophic factors, BDNF and GDNF mRNAs. Rasagiline and propargylamine inhibited the cleavage and subsequent activation of pro-caspase-3 and poly ADP-ribose polymerase. Additionally, these compounds significantly down-regulated PKCgamma mRNA and decreased the level of the pro-apoptotic proteins, Bax, Bad, Bim and H2A.X. Rasagiline and propargylamine both regulated amyloid precursor protein (APP) processing towards the non-amyloidogenic pathway. These structure-activity studies have provided evidence that propargylamine promoted neuronal survival via neuroprotective/neurorescue pathways similar to that of rasagiline. In addition, recent study demonstrated that chronic low doses of rasagiline administered to mice subsequently to 1 methyl-4 phenyl 1,2,3,6 tetrahydropyridine (MPTP), rescued dopaminergic neurons in the substantia nigra pars compacta via activation of the Ras-PI3K-Akt survival pathway, suggesting that rasagiline may possess a disease modifying activity.

Euler-Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines.

The trajectories, referred to as lifelines, of individual microorganisms in an industrial scale fermentor under substrate limiting conditions were studied using an Euler-Lagrange computational fluid dynamics approach. The metabolic response to substrate concentration variations along these lifelines provides deep insight in the dynamic environment inside a large-scale fermentor, from the point of view of the microorganisms themselves. We present a novel methodology to evaluate this metabolic response, based on transitions between metabolic "regimes" that can provide a comprehensive statistical insight in the environmental fluctuations experienced by microorganisms inside an industrial bioreactor. These statistics provide the groundwork for the design of representative scale-down simulators, mimicking substrate variations experimentally. To focus on the methodology we use an industrial fermentation of Penicillium chrysogenum in a simplified representation, dealing with only glucose gradients, single-phase hydrodynamics, and assuming no limitation in oxygen supply, but reasonably capturing the relevant timescales. Nevertheless, the methodology provides useful insight in the relation between flow and component fluctuation timescales that are expected to hold in physically more thorough simulations. Microorganisms experience substrate fluctuations at timescales of seconds, in the order of magnitude of the global circulation time. Such rapid fluctuations should be replicated in truly industrially representative scale-down simulators.

The growth hormone binding protein as a paradigm of the erythropoietin superfamily of receptors.

The growth hormone (GH) receptor belongs to a novel receptor family which shares significant amino-acid sequence homology and includes prolactin receptors, erythropoietin receptors and several cytokines' receptors. GH and three other members of this family of receptors have been shown to have circulating soluble forms. The present review summarizes our knowledge on receptor related binding proteins, discusses their possible biological effects and suggests their use in novel assays for their ligands. The GH-binding protein (GH-BP) was the first to have been described and is used as a model for the concept. A series of indirect pieces of evidence suggest that the measurement of circulating GH-BP may enable an evaluation of the GH-receptor. When covalently bound to GH, GH-BP has been shown to slow the clearance of GH. On the other hand GH-BP competes with the GH-receptor for GH binding and, thus, diminishes the biological effect of GH. We suggest a biological role for GH-BP as follows: an increase in the availability of GH results not only in the upregulation of the GH-receptor but also in increased turnover of this receptor, its internalization and recycling. This is followed by a concomitant increase in GH-BP which, in turn, mitigates the effect of GH by competing with the receptor on GH binding. The extracellular domain of the GH-receptor is homologous, to a large extent, with the sequence of several receptors for hormones and cytokines, which have recently been cloned.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of human growth hormone binding to somatogenic and lactogenic receptors by monoclonal antibodies to human growth hormone.

The relationship between the structure of human growth hormone (hGH) and the hormone-receptor interaction was investigated by studying the effects of specific monoclonal antibodies (MAbs) to hGH on the binding of [125I]hGH to rabbit liver and mouse liver microsomes. Receptor binding assays were carried out using a constant dose (1 ng) of [125I]hGH and varying concentrations of MAbs. The assay was carried out in the presence of either excess ovine prolactin for the measurement of somatogenic (SOM) binding sites, or excess bovine growth hormone for the determination of lactogenic (LAC) binding sites. Anti-hGH MAbs were found to have a whole spectrum of effects on hGH binding, including inhibitory, non-effect and enhancing activities. Enhancement of the binding of [125I]hGH to both SOM and LAC receptors was observed in liver membranes of rabbit or mouse. The observed amplified signal of [125I]hGH binding to various receptors in the presence of MAb no. 8 may be due to conformational changes which occur following MAb binding to hGH. On the other hand, most of the other MAbs caused inhibition of [125I]hGH binding. A negative correlation exists between the cross-reaction of various MAbs with the N-terminus truncated forms of hGH (Met14-hGH or Met8Leu-hGH) and their respective KD/IC50 values enabled the evaluation of the crucial role of the N-terminus region in hGH binding to both LAC and SOM receptors. MAb nos 1 and 19, which are directed towards acid residues 95-134 and the C-terminus, inhibited SOM binding more potently than LAC binding. Thus, it seems that these mid-molecule and C-terminus regions are also important in hGH binding, and that they play a role in the partial overlap of SOM and LAC binding.