Diphtheria in a 13 year old adolescent girl: Management challenges

Background: Diphtheria is an acute toxic infection which is associated with a high morbidity and mortality and can pose management challenges especially in the absence of proper diagnostic and therapeutic facilities.Case report: A.S. was a 13 year old girl who presented with fever of five days duration, dysphagia and neck swelling of 4 days duration and sore throat and hoarse voice of 3days duration. Her illness started a day after returning from a 4-day holiday youth camp. She received only oral polio vaccine immunization in childhood. Significant physical examinationfindings included a swollen neck, a greyish membrane covering the soft palate and uvula with haemorrhagic spots. The pharynx, anterior nares and the nasal turbinates were inflamed and erythematous. A working diagnosis of respiratory diphtheria was made. Throat swab microscopy showed club shaped Gram positive baccilli. Appropriate culture medium for C. diphtheriawas not available. She received intravenous crystalline penicillin and metronidazole and lateroral erythromycin in an isolated ward. On the 6th day of admission she developed cardiac and neurologic complications–bradycardia (PR=40bpm), hypotension (BP=70/40mmHg), drooling of saliva and paraparesis. Electrocardiography confirmed a complete heart block. She died on the 11th day of admission while efforts were being made to raise funds for a cardiac pace maker. Conclusion: Management of this vaccine preventable disease requires a high index of suspicion and diphtheria antitoxin should be made readily available

Experimental Investigation of Water Spray Cooling for Temperature Reduction in Liquid Piston Compressor

The objective of this study is to analyze the effect of spray cooling in a liquid piston compressor during the compression of air in terms of temperature abatement and compression efficiency. The liquid piston can effectively cover any irregular containers making its surface area to volume ratio better than conventional reciprocating pistons. This plays an important role in increased heat transfer to the outer surface resulting in improved efficiency. As the compression process has the minimum work input during an isothermal compression, the process path needs to shift from the polytropic curve towards the isothermal curve for higher efficiency. Recently, various methodologies have been tested in the liquid piston for increasing heat transfer from the chamber such as optimal compression trajectories, placing porous media inserts into the chamber, and introducing hollow spheres in the chamber. Also, several studies have presented spray cooling as a viable option for heat transfer enhancement in compressors due to its high specific heat and fine atomization. In this study, to shift compression trajectory towards an isothermal curve, spray cooling is investigated for a compression ratio of 2 in a liquid piston compressor. Experiments are performed in the liquid piston setup with water as the medium and a polypropylene chamber. The experimental setup for the spray system consists of a pump, pressure regulator, flowmeter, data acquisition system, and nozzles. For the spray; full cone and hollow cone nozzles were selected as they provide an even distribution of droplets with moderate to fine diameters. Spray angles from 60° to 120° for full cone nozzles, and injection line pressure from 275 kPa to 550 kPa are tested for various stroke times of compression. A temperature drop from 59°C to 35°C was observed when spray cooling was introduced with a full cone nozzle with 60° spray angle and 275 kPa injection pressure for a compression ratio of 2. Similarly, a significant drop in temperature of the air was observed with the use of spray from hollow cone nozzles with different spray angles and injection pressures. Experimental results indicated that full cone nozzles perform better than hollow cone nozzles due to higher flow rates and an even droplet distribution; even though the hollow cone nozzles have a finer atomization compared to the full cone nozzles. Higher injection line pressures resulted in greater temperature drop because of higher mass loading and finer droplet diameters, however higher injection pressures require higher pump work. Variation in spray angle did not show any significant change in temperature drop. Spray cooling was most effective for shorter compression stroke time along with higher flow rates. The polytropic index of compression approximately changed from 1.2 without spray to 1.04 – 1.08 when spray cooling was introduced. This corresponds to a 9 – 13% improvement in compression efficiency. This shows that by incorporating water spray the efficiency of liquid piston compressors can be significantly improved. Further investigations can be explored for optimization of spray characteristics and with multi-nozzle spray setups for improvements in compressor efficiency

An Innovative Geocentric Decision Support Solution to Comprehensive Planning, Design, Operation, and Management of Urban Drainage Systems

Geographic Information System (GIS) is quickly becoming a critical component to develop and sustain asset management for today’s wastewater utilities as most of their data is geographically referenced. This technology offers sophisticated data management and spatial analysis capabilities that can greatly improve and facilitate urban drainage infrastructure modeling and analysis applications. This paper presents a comprehensive GIS-based decision support system that integrates several technologies for use in the effective management of urban stormwater collection systems. It explicitly integrates ESRI ArcGIS geospatial model with advanced hydrologic, hydraulic, and water quality simulation algorithms, nature-based global optimization techniques including genetic algorithms for design and calibration of stormwater management models, automated dry weather flow generation and allocation, and automated subcatchment delineation and parameter extraction tools to address every facet of urban drainage infrastructure management. The geocentric interface allows seamless communication among the various modules. The resulting decision support system effortlessly reads GIS datasets, extracts necessary modeling information, and automatically constructs, loads, designs, calibrates, analyzes and optimizes a representative urban drainage model considering hydrologic and hydraulic performance requirements. It also makes it easy to run, simulate and compare various modeling scenarios, identify system deficiencies, and determine cost-effective physical and operational improvements to achieve optimum performance and regulatory compliance. These combined capabilities provide favorable geospatial environment to assist wastewater utilities in planning, designing, and operating reliable systems and in optimizing their capital improvement programs

Discovery of germacrene A synthases in Barnadesia spinosa: The first committed step in sesquiterpene lactone biosynthesis in the basal member of the Asteraceae

The Andes-endemic Barnadesioideae lineage is the oldest surviving and phylogenetically basal subfamily of the Asteraceae (Compositae), a prolific group of flowering plants with world-wide distribution (∼24,000 species) marked by a rich diversity of sesquiterpene lactones (STLs). Intriguingly, there is no evidence that members of the Barnadesioideae produce STLs, specialized metabolites thought to have contributed to the adaptive success of the Asteraceae family outside South America. The biosynthesis of STLs requires the intimate expression and functional integration of germacrene A synthase (GAS) and germacrene A oxidase (GAO) to sequentially cyclize and oxidize farnesyl diphosphate into the advanced intermediate germacrene A acid leading to diverse STLs. Our previous discovery of GAO activity conserved across all major subfamilies of Asteraceae, including the phylogenetically basal lineage of Barnadesioideae, prompted further investigation of the presence of the gateway GAS in Barnadesioideae. Herein we isolated two terpene synthases (BsGAS1/BsGAS2) from the basal Barnadesia spinosa (Barnadesioideae) that displayed robust GAS activity when reconstituted in yeast and characterized in vitro. Despite the apparent lack of STLs in the Barnadesioideae, this work unambiguously confirms the presence of GAS in the basal genera of the Asteraceae. Phylogenetic analysis reveals that the two BsGASs fall into two distinct clades of the Asteraceae's GASs, and BsGAS1 clade is only retained in the evolutionary closer Cichorioideae subfamily, implicating BsGAS2 is likely the ancestral base of most GASs found in the lineages outside the Barnadesioideae. Taken together, these results show the enzymatic capacities of GAS and GAO emerged prior to the subsequent radiation of STL-producing Asteraceae subfamilies

Ethanol and production of the hepatotoxic metabolite of acetaminophen in healthy adults

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109855/1/cptclpt200062.pd

Pain from a Bullet Lingers on: An Uncommon Case of Lead Toxicity

Lead toxicity from a retained bullet as a cause for abdominal pain is rarely considered. Given its unpredictable latent period and nonspecific clinical symptoms, such cases are difficult to diagnose but may be fatal if unrecognized. We present the case of a 48-year-old man who presented with complaints of abdominal pain, weight loss and constipation. His past history was significant for a gunshot wound to the left hip about 20 years before. Radiographic studies confirmed the same with the presence of numerous intra-articular bullet fragments and a calcified hemarthrosis surrounding the left femoral head. Blood lead levels were elevated following which the patient was started on chelation therapy with succimer which resulted in symptomatic improvement. The aim of this paper is to highlight the importance of considering lead toxicity from a retained bullet as a cause of abdominal pain and to review the relevant literature

RNA:protein ratio of the unicellular organism as a characteristic of phosphorous and nitrogen stoichiometry and of the cellular requirement of ribosomes for protein synthesis

Background Mean phosphorous:nitrogen (P:N) ratios and relationships of P:N ratios with the growth rate of organisms indicate a surprising similarity among and within microbial species, plants, and insect herbivores. To reveal the cellular mechanisms underling this similarity, the macromolecular composition of seven microorganisms and the effect of specific growth rate (SGR) on RNA:protein ratio, the number of ribosomes, and peptide elongation rate (PER) were analyzed under different conditions of exponential growth. Results It was found that P:N ratios calculated from RNA and protein contents in these particular organisms were in the same range as the mean ratios reported for diverse organisms and had similar positive relationships with growth rate, consistent with the growth-rate hypothesis. The efficiency of protein synthesis in microorganisms is estimated as the number of active ribosomes required for the incorporation of one amino acid into the synthesized protein. This parameter is calculated as the SGR:PER ratio. Experimental and theoretical evidence indicated that the requirement of ribosomes for protein synthesis is proportional to the RNA:protein ratio. The constant of proportionality had the same values for all organisms, and was derived mechanistically from the characteristics of the protein-synthesis machinery of the cell (the number of nucleotides per ribosome, the average masses of nucleotides and amino acids, the fraction of ribosomal RNA in the total RNA, and the fraction of active ribosomes). Impairment of the growth conditions decreased the RNA:protein ratio and increased the overall efficiency of protein synthesis in the microorganisms. Conclusion Our results suggest that the decrease in RNA:protein and estimated P:N ratios with decrease in the growth rate of the microorganism is a consequence of an increased overall efficiency of protein synthesis in the cell resulting from activation of the general stress response and increased transcription of cellular maintenance genes at the expense of growth related genes. The strong link between P:N stoichiometry, RNA:protein ratio, ribosomal requirement for protein synthesis, and growth rate of microorganisms indicated by the study could be used to characterize the N and P economy of complex ecosystems such as soils and the oceans

Age- and Concentration-Dependent Elimination Half-Life of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Seveso Children

OBJECTIVE: Pharmacokinetic and statistical analyses are reported to elucidate key variables affecting 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elimination in children and adolescents. DESIGN: We used blood concentrations to calculate TCDD elimination half-life. Variables examined by statistical analysis include age, latency from exposure, sex, TCDD concentration and quantity in the body, severity of chloracne response, body mass index, and body fat mass. PARTICIPANTS: Blood was collected from 1976 to 1993 from residents of Seveso, Italy, who were < 18 years of age at the time of a nearby trichlorophenol reactor explosion in July 1976. RESULTS: TCDD half-life in persons < 18 years of age averaged 1.6 years while those ≥18 years of age averaged 3.2 years. Half-life is strongly associated with age, showing a cohort average increase of 0.12 year half-life per year of age or time since exposure. A significant concentration-dependency is also identified, showing shorter half-lives for TCDD concentrations > 400 ppt for children < 12 years of age and 700 ppt when including adults. Moderate correlations are also observed between half-life and body mass index, body fat mass, TCDD mass, and chloracne response. CONCLUSIONS: Children and adolescents have shorter TCDD half-lives and a slower rate of increase in half-life than adults, and this effect is augmented at higher body burdens. RELEVANCE: Modeling of TCDD blood concentrations or body burden in humans should take into account the markedly shorter elimination half-life observed in children and adolescents and concentration-dependent effects observed in persons > 400–700 ppt

Recent trends in publication of basic science and clinical research by United States investigators in anesthesia journals

<p>Abstract</p> <p>Background</p> <p>United States anesthesia research production declined sharply from 1980-2005. Whether this trend has continued despite recent calls to improve output is unknown. We conducted an observational internet analysis to quantify American basic science and clinical anesthesia research output in 14 anesthesia journals with impact factors greater than one at three-year intervals during the past decade.</p> <p>Results</p> <p>American investigators published 1,486 (21.7%) of the total of 6,845 research articles identified in anesthesia journals in 2001, 2004, 2007, and 2010. Approximately two-thirds of all US articles were published in <it>Anesthesiology </it>and <it>Anesthesia and Analgesia</it>. There was a significant correlation (r²= 0.316; P = 0.036) between the number of articles published by American authors in each anesthesia journal and the corresponding journal's impact factor in 2010. Significantly (P < 0.05; Pearson's Chi-square) fewer basic science articles were published in 2007 and 2010 compared with 2001. US clinical research output also declined in 2007 (201; 15.7%) compared with 2001 (266; 19.1%) and 2004, but an increase occurred in 2010 (279; 21.8%, P < 0.05 versus 2007).</p> <p>Conclusions</p> <p>The results indicate that US anesthesia research output continued to decrease from 2001 to 2007. An increase in clinical but not basic science research was observed in 2010 compared with 2007, suggesting that a modest recovery in clinical research production may have begun.</p

The World Trade Center Disaster and the Health of Workers: Five-Year Assessment of a Unique Medical Screening Program

BACKGROUND: Approximately 40,000 rescue and recovery workers were exposed to caustic dust and toxic pollutants following the 11 September 2001 attacks on the World Trade Center (WTC). These workers included traditional first responders, such as firefighters and police, and a diverse population of construction, utility, and public sector workers. METHODS: To characterize WTC-related health effects, the WTC Worker and Volunteer Medical Screening Program was established. This multicenter clinical program provides free standardized examinations to responders. Examinations include medical, mental health, and exposure assessment questionnaires; physical examinations; spirometry; and chest X rays. RESULTS: Of 9,442 responders examined between July 2002 and April 2004, 69% reported new or worsened respiratory symptoms while performing WTC work. Symptoms persisted to the time of examination in 59% of these workers. Among those who had been asymptomatic before September 11, 61% developed respiratory symptoms while performing WTC work. Twenty-eight percent had abnormal spirometry; forced vital capacity (FVC) was low in 21%; and obstruction was present in 5%. Among nonsmokers, 27% had abnormal spirometry compared with 13% in the general U.S. population. Prevalence of low FVC among nonsmokers was 5-fold greater than in the U.S. population (20% vs. 4%). Respiratory symptoms and spirometry abnormalities were significantly associated with early arrival at the site. CONCLUSION: WTC responders had exposure-related increases in respiratory symptoms and pulmonary function test abnormalities that persisted up to 2.5 years after the attacks. Long-term medical monitoring is required to track persistence of these abnormalities and identify late effects, including possible malignancies. Lessons learned should guide future responses to civil disasters