Continuous improvement of a bioengineering CURE: Preparing students for a changing world

Based on recent education reform guidelines to prepare professionals who are able to handle new technological, economic, social, and environmental challenges, pedagogical modifications are deemed necessary by the educators. Specifically, in biology, the rapid changes in the content and biological products demand changes in the curriculum. We aim to address this current need by providing an example of a course that was redesigned to meet the current trends of biological engineering education. In this course-based undergraduate research experience (CURE), learning objectives and possible outcomes were developed and assessment mapping was performed to align the course objectives with the Accreditation Board for Engineering and Technology (ABET) recommendations. A description of how one can assess authentic inquiry courses while adhering to the recommendations are discussed. For example, in this particular course, students completed weekly reflection assignments, maintained lab notebooks that were graded every week, presented their research to their peers at the end of the semester, and submitted a final paper to be graded. "Holistic" engineering is crucial for the all-around development of a 21st century engineer. Altering the traditional lecturing with more hands-on learning is crucial for the development of professional and communication skills of students. Such alterations could lead to the production of well-rounded life-long learners to serve the upcoming world.

Metal Ion Binding in Wild-Type and Mutated Frataxin: A Stability Study

This work studies the stability of wild-type frataxin and some of its variants found in cancer tissues upon Co2+ binding. Although the physiologically involved metal ion in the frataxin enzymatic activity is Fe2+, as it is customarily done, Co2+ is most often used in experiments because Fe2+ is extremely unstable owing to the fast oxidation reaction Fe2+ → Fe3+. Protein stability is monitored following the conformational changes induced by Co2+ binding as measured by circular dichroism, fluorescence spectroscopy, and melting temperature measurements. The stability ranking among the wild-type frataxin and its variants obtained in this way is confirmed by a detailed comparative analysis of the XAS spectra of the metal-protein complex at the Co K-edge. In particular, a fit to the EXAFS region of the spectrum allows positively identifying the frataxin acidic ridge as the most likely location of the metal-binding sites. Furthermore, we can explain the surprising feature emerging from a detailed analysis of the XANES region of the spectrum, showing that the longer 81-210 frataxin fragment has a smaller propensity for Co2+ binding than the shorter 90-210 one. This fact is explained by the peculiar role of the N-terminal disordered tail in modulating the protein ability to interact with the metal.

A study to establish international diagnostic reference levels for paediatric computed tomography

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.

Search for low-mass weakly interacting massive particles with SuperCDMS

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30  GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42)  cm(2) at 8  GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6  GeV/c(2).

Patient skin dosimetry in interventional cardiology in the Czech Republic

In this study, skin dosimetry of patients undergoing interventional cardiology procedures is presented. Three hospitals were included. Two methods were used for skin dosimetry--radiochromic dosimetry films and reconstruction of skin dose distribution based on examination protocol. Maximum skin doses (MSD) obtained from both methods were compared for 175 patients. For patients for whom the film MSD was >1 Gy, the reconstruction MSD differed from the film MSD in the range of ± 50 % for 83 % of patients. For remaining patients, the difference was higher and it was caused by longer fluoroscopy time. For 59 patients for whom the cumulative dose was known, the cumulative dose was compared with the film MSD. Skin dosimetry with radiochromic films is more accurate than the reconstruction method, but films do not include X-ray fields from lateral projections whilest reconstructions do.

Organ and effective doses from verification techniques in image-guided radiotherapy

The purpose of this work was an evaluation of organ doses and effective doses from three verification techniques in Image-Guided Radiotherapy: from kilovoltage (kV) cone beam computed tomography (CBCT) scans, from two orthogonal kV images and from two orthogonal megavoltage (MV) images for two different treatment sites: pelvis and head and neck (H&N). For comparison reasons, organ doses and effective doses from prostate and H&N radiotherapy were also evaluated. Measurements of organ doses were performed in a male anthropomorphic Rando phantom by means of thermoluminescent dosemeters. In this investigation, measured organ doses from one CBCT scan, from two MV images and from two kV images of pelvis represent typically 1-6, 1-10 and 0.05-1 %, respectively, of organ doses resulting from one fraction of prostate radiotherapy. The maximum effective doses from CBCT scans, kV images and MV images of pelvis are 5.6, 0.8 and 11.9 mSv, respectively.

Search for weakly interacting massive particles with the first five-tower data from the cryogenic dark matter search at the soudan underground laboratory

We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October 2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10;{-44} cm;{2} (4.6x10;{-44} cm;{2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c;{2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c;{2}, and significantly restricts the parameter space for some favored supersymmetric models.

Role of aberrant glycosylation of IgA1 molecules in the pathogenesis of IgA nephropathy

Studies of the properties of immune complexes (IC) in the circulation, urine, and mesangium of IgA nephropathy (IgAN) patients have provided data relevant to the pathogenesis of this disease. IC contain predominantly polymeric IgA1 molecules which are deficient in galactose (Gal) residues on O-linked glycan chains in the hinge region (HR) of their heavy (H) chains. As a result of this aberrancy, a novel antigenic determinant(s) involving N-acetylgalactosamine (GalNAc) and perhaps sialic acid (SA) of O-linked glycans is generated and recognized by naturally occurring GalNAc-specific antibodies. Thus, IC in IgAN consist of Gal-deficient IgA1 molecules as an antigen, and GalNAc-specific IgG and/or IgA1 as an antibody. IgG antibodies to Gal-deficient IgA1 are probably induced by cross-reactive microbial antigens; they are present at variable levels not only in humans with or without IgAN but also in many phylogenetically diverse vertebrate species. Incubation of human mesangial cells with IC from sera of IgAN patients indicated that stimulation of cellular proliferative activity was restricted to the large (>800 kDa) complexes. These findings suggest that experimental approaches that prevent the formation of large Gal-deficient IgA1-IgG IC may be applied ultimately in an immunologically mediated therapy.

Spinal Extradural Arachnoid Cyst Causing Cord Compression in a 15-Year-Old Girl: A Case Report

The authors describe the case of a fifteen-year-old girl with progressive paraparesis of the lower limbs that was caused by an intraspinal extradural dorsal arachnoid cyst at the level of Th 3-6. Diagnosis was established with MRI and MRI myelography. The latter revealed the CSF-like content of the cyst. The patient underwent laminotomy and en bloc resection of the cyst. Ligation of the pedicle of the cyst was done with laminoplasty. Quick and complete recovery was observed after surgery.

First results from the Cryogenic Dark Matter Search in the Soudan Underground Laboratory

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg d of Ge net exposure after cuts for recoil energies between 10 and 100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross section for all WIMP masses above 15 GeV/c2, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10(-43) cm2 at a WIMP mass of 60 GeV/c2.

Heat exchange between the organism and environment under conditions of weightlessness; methodical approach

The spontaneous streaming of air around surfaces of warm bodies conditioned by gravitation is missing in the weightless condition. This implies a change in the thickness of the surface air layer and its interference with the heat output of an organism. The paper describes the use of an electric dynamic katathermometer (EDK) for automatic and continuous scanning of heat output and presents results of measuring basic characteristics of the surface layer under defined laboratory conditions, and their relation to heat output.

Respiratory gas exchange as an indicator of changed radioresistance in mammals

The paper deals with the problem of detection of radio-protective effects during irradiation. The method used is based on the fact that the known effective pharmacological and chemical radioprotectives (aminoethylthiouronium bromide HBr (AET), cystamine, sodium fluoroacetate (FAc), 5-hydroxytryptamine (5-HT), 5-methoxytryptamine (5-MT) and others) interfere directly or indirectly with enzymatic steps in energy metabolism of the organism. In mammals they induce at the same time an increase of resistance against ionizing radiation and a decrease in the respiratory gas exchange expressed by a depressed oxygen consumption. In experiments carried out on male mice of the H strain and male rats of the Wistar strain it was found that animals respiring a hypoxic mixture (5-8% O2, STPD), have a lower oxygen consumption during the period of increased radioresistance similar to that seen during the effect of radioprotective drugs. This finding is of practical importance as it enables one to evaluate quantitatively the effect of radioprotective measures (including the hypoxia) in individual experimental animals during the course of irradiation.

Comparison of standard and alternative prehospital resuscitation in uncontrolled hemorrhagic shock and head injury

BACKGROUND

Recently acquired data suggest that prehospital fluid resuscitation may worsen outcome of patients with penetrating torso trauma. In patients with head injury, delayed resuscitation (DR) could lead to secondary cerebral ischemia. We hypothesized that standard prehospital resuscitation (SPR) with lactated Ringer's solution or diaspirin cross-linked hemoglobin would reduce secondary cerebral ischemia compared with DR.

METHODS

Anesthetized swine were randomized to receive SPR, diaspirin cross-linked hemoglobin, or DR after cryogenic brain injury and uncontrolled hemorrhagic shock and studied for 70 minutes after the combined insults.

RESULTS

Hemorrhage volume was lowest in the DR group (p<0.05). There were no significant differences between the groups in systemic or cerebral oxygen delivery. Intracranial pressure was lower and cerebral perfusion pressure higher in the diaspirin cross-linked hemoglobin group compared with SPR (p<0.05). Lesion size was greatest in the SPR group, but the difference was not significant.

CONCLUSION

In this model, SPR leads to secondary cerebral ischemia. DR is no worse and may be superior to conventional prehospital resuscitation with lactated Ringer's solution.

Cerebrovascular reserve capacity many years after vasospasm due to aneurysmal subarachnoid hemorrhage. A transcranial Doppler study with acetazolamide test

BACKGROUND AND PURPOSE

Vasospasm in aneurysmal subarachnoid hemorrhage results in proliferative vasculopathy. Systemic hypertension also causes vascular hypertrophy. Both of these histological changes can lead to rigidity of the cerebrovascular system, reducing its autoregulatory capacity.

METHODS

Blood flow velocity (BFV) in the middle cerebral artery at rest and cerebrovascular reserve capacity (CVRC) (percent rise in BFV after acetazolamide stimulation) measured by means of transcranial Doppler sonography were studied many years after aneurysmal subarachnoid hemorrhage in patients with proven cerebral vasospasm (mean BFV > 160 cm/s). The BFV under resting conditions and the CVRC values of the ipsilateral and the contralateral hemispheres were measured in 29 patients (mean age, 43 years; mean follow-up, 4.6 years) and compared with those of control subjects.

RESULTS

Persistent high BFV (> 120 cm/s) was found in three patients in the peripheral branch of the ipsilateral middle cerebral artery. In the main trunks of the arteries of the anterior circle of Willis, BFV was normal in all cases. CVRC was normal in all patients (ipsilateral, 52 +/- 21%; contralateral, 56 +/- 17%); values did not differ significantly from each other or from the control value (45 +/- 18%). The higher value of CVRC on the contralateral side was found to be statistically significant in selected groups (hypertensive patients and patients with residual infarct on late CT).

CONCLUSIONS

Proliferative vasculopathy developed at the time of vasospasm must have resolved and did not reduce late vasoreactivity. Comorbidity with hypertension also did not seem to influence the late vasoreactivity toward normalization.

Production of a specific major histocompatibility complex class I-restricted epitope by ubiquitin-dependent degradation of modified ovalbumin in lymphocyte lysate

Peptide epitopes presented through class I major histocompatability complex (MHC class I) on the cell surface, are generated by proteolytic processing of protein-antigens in the cytoplasm. The length and amino acid sequence determine whether a given peptide can fit into the peptide binding groove of class I heavy chain molecules and subsequently be presented to the immune system. The mode of action of the processing pathway is therefore of great interest. To study the processing mechanism of MHC class I-restricted intracellular antigens, we reconstituted the proteolytic processing of a model antigen in a cell-free system. Incubation of oxidized and urea-treated OVA in lymphocyte lysate resulted in partial degradation of the antigen. Degradation of the antigen depended on the presence of ATP. Addition of methylated ubiquitin abolished the reaction which was then restored by addition of an excess of native ubiquitin, indicating that the breakdown of the antigen in lymphocyte lysate is mediated by the ubiquitin proteolytic system. Upon incubation of modified OVA in lymphocyte lysate, a specific antigenic peptide was generated. The peptide was recognized by cytotoxic T lymphocytes directed against OVA-derived, H-2Kb-restricted peptide (SIINFEKL), and by a monoclonal antibody that recognizes cell-bound Kb-SIINFEKL complexes. Formation of the peptide epitope depended on the presence of ATP and ubiquitin. These results indicate that proteolytic processing of modified OVA is carried out by the ubiquitin-mediated degradation system. The experimental system described provides a tool to analyze the molecular mechanisms underlying the generation of specific, MHC class I-restricted peptide epitopes.

Metabolism and Energetics of Lactococcus lactis during Growth in Complex or Synthetic Media

When Lactococcus lactis was grown in various complex or synthetic media, the fermentation of glucose remained homolactic whatever the medium used, with a global carbon balance of about 87%. Moreover, the nitrogen balance was not equilibrated, indicating that some amino acids led to the production of unknown nitrogen-containing carbon compounds while part of the glucose might contribute to anabolic pathways. In minimal medium containing six amino acids, a high concentration of serine was deaminated to pyruvate. This did not occur in more complete media, suggesting the presence of a regulation of this phenomenon by an amino acid. Ammonia produced during serine consumption was partly reconsumed after serine exhaustion. The values for biomass yield and biomass yield relative to ATP (Y(infATP)), the maximal growth rate, the specific rate of glucose consumption, and the corresponding rate of ATP synthesis all increased with the complexity of the medium, amino acid composition having the most pronounced effect. The Y(infATP) values were shown to range from 6.6 to 17.6 g of biomass(middot)mol of ATP(sup-1) on minimal and complex media.

Craniospinal irradiation for acute lymphoblastic leukemia with central nervous system disease at diagnosis: a report from the Children's Cancer Group

PURPOSE

This study attempted to determine if central nervous system (CNS) disease at diagnosis is a poor prognostic factor in children with acute lymphoblastic leukemia (ALL) and whether 6 Gy of spinal irradiation is an adequate dose for these patients.

METHODS AND MATERIALS

Previously the Children's Cancer Group (CCG) treated patients with ALL and CNS disease at diagnosis with cranio (24 Gy)-spinal (12 Gy) irradiation, as well as systemic and intrathecal chemotherapy. In a series of CCG trials completed in 1989 the spinal dose was empirically reduced to 6 Gy for patients receiving systemic chemotherapy with an intensive consolidation phase to limit hematopoietic toxicity. The spinal dose was left at 12 Gy for patients treated with a less intensive consolidation phase.

RESULTS

With a median follow-up for surviving patients of 74 months, the 5-year event-free survival for 53 patients with CNS disease at diagnosis was 69 +/- 13% (+/- 2 standard deviations), similar to the value obtained for 3364 patients without CNS disease, 67 +/- 2%. Corresponding values for 5-year survival were 77 +/- 12% and 80 +/- 1%, and for freedom from isolated first CNS relapse, were 90 +/- 9% and 94 +/- 1%. Event-free survival, survival, and freedom from isolated first CNS relapse in the 6-Gy group were as good as in the 12-Gy group.

CONCLUSION

CNS disease at diagnosis is not a poor prognostic factor for children with ALL who are treated with intensive systemic chemotherapy, craniospinal irradiation, and intrathecal chemotherapy. Six Gy is an adequate dose of spinal irradiation for these patients.

Nonoccupational determinants of blood lead concentrations in a general population

We investigated the influence of various nonoccupational factors on blood lead levels (PbB) in a sample from the general population of southern Germany. Some 1703 men and 1661 women, aged 28-67 years, were examined in the first follow-up examination of the MONICA Augsburg cohort study in 1987-1988. Their mean PbB was 90 micrograms/l (SD:35.9) for men and 65 micrograms/l (26.4) for women. Only 5% of the men and 1% of all women exceeded a PbB level of 150 micrograms/l indicating low-level lead exposure in this population. Blood lead was significantly associated with haematocrit values (P < 0.001) and the shape of this association was curvilinear. Per gram of alcohol consumed, intake of beer had a lower impact on PbB than wine, presumably due to differential lead content in these alcoholic beverages. The alcohol-PbB associations were stronger for women than for men. The impact of smoking was generally moderate but again more prominent in women. In particular, the covariate adjusted odds ratios for women of childbearing age (28-47 years) to have PbB levels above 100 micrograms/l were 2.5 (95% confidence interval (CI): 1.3-4.7) for smoking versus non-smoking females, 2.6 (95% CI: 1.1-6.0) for women drinking up to 40 g alcohol/day compared to abstainers, and 8.9 (95% CI: 3.2-25.1) for those drinking more than 40 g alcohol/day. Other factors like age, body mass, rural place of residence, and education or job position, had only minor influences on PbB. We conclude that haematocrit values should always be considered as potential confounders in low-level lead exposure research. High alcohol consumption and cigarette smoking are strongly related to elevated blood lead concentrations in the general population and may thereby convey additional health hazards such as impaired child development or blood pressure elevations. This deserves proper public health recognition [corrected].

Our experience in the evaluation of the thermal comfort during the space flight and in the simulated space environment

The paper presents the results of the mathematical modelling the effects of hypogravity on the heat output by the spontaneous convection. The theoretical considerations were completed by the experiments "HEAT EXCHANGE 1" performed on the biosatellite "KOSMOS 936". In the second experiment "HEAT EXCHANGE 2" accomplished on the board of the space laboratory "SALYUT 6" was studied the effect of the microgravity on the thermal state of a man during the space flight. Direct measurement in weightlessness prowed the capacity of the developed electric dynamic katathermometer to check directly the effect of the microgravity on the heat output by the spontaneous convection. The role of the heat partition impairment's in man as by the microgravity, so by the inadequate forced convection are clearly expressed in changes of the skin temperature and the subjective feeling of the cosmonaut's thermal comfort. The experimental extension of the elaborated methods for the flexible adjustment of the thermal environment to the actual physiological needs of man and suggestions for the further investigation are outlined.

[Prognostication of man's health status in response to gravity-induced blood shifts based on continuous noninvasive measurement of arterial blood pressure using the Pen'iaz method]

Exposure to +Gz acceleration, orthostatic tilt tests and LBNP tests causes distinct blood shifts and deterioration of cerebral circulation. In this case syncope episodes may be prevented by continuous monitoring of circulation parameters, specifically arterial pressure (AP). Our investigations have shown that continuous AP measurement by the Penjaz noninvasive technique may help earlier prediction of the health status in response to gravity-induced blood shifts. In this situation the development of a pre-collapse state is preceded by an emergence of distinct AP waves of the second-third order accompanied by a critical drop of pulse pressure. It is concluded that continuous AP measurement in the finger according to the Penjaz noninvasive technique holds promise as a medical monitoring method in a altered gravitational field.

[Comparison of cytotoxicity of a chemical and a photopolymerizing composite filling material in a in vitro experiment]

The authors comparise the toxicity of a photopolymerizing (Silux 3M) and a chemical polymerizing (Silar 3M) composite by unspecific application on an in vitro cell culture of a permanent HEp-2-line. It was observed that a greater and more extensive injury was caused by the photopolymerizing material.

Developmental orofacial deficits associated with multimodal cancer therapy: case report

Multimodal cancer therapy for pediatric head and neck tumors may be associated with significant developmental orofacial morbidity. This report details these effects in a child (C.I.) diagnosed at 2.5 years of age with a rhabdomyosarcoma, primary to the left buccinator. This case is of interest as C.I. has an unaffected identical twin (D.I.) for comparative study. Both were assessed by comparing panoramic radiographs and lateral and frontal tracings of cephalometric radiographs obtained at 8.25 years of age. C.I. had multiple dental anomalies which included agenesis, ectopia, crown malformation, and root malformation. Root malformation, ectopia, and agenesis were restricted to the left dentition, whereas crown malformation was noted bilaterally. C.I. had a generalized craniofacial skeletal hypoplasia relative to D.I. in all three planes, growth defects were greater on the side of the tumor, and the mandible was affected more than the nasomaxillary complex.

[Production of gamma interferon and interleukin 2 in mononuclear spleen cells stimulated with concanavalin A]

Relationships between interleukine-2 and interferon production by mononuclear cells of mouse spleens stimulated with concanavalin A were studied.

Do pressure-demand breathing systems safeguard against inward leakage?

Rescue operations conducted in toxic atmospheres require respiratory protective equipment capable of providing a very high degree of protection. A slight positive pressure in the facepiece throughout the breathing cycle is used in the pressure-demand, compressed-air breathing apparatus to eliminate any inward leakage. In the present work an inward leakage test with sulphur hexafluoride (SF6) was used to measure facepiece penetration in a pressure-demand system at different work loads. During the test, inspiratory-flow pressure variations within the facepiece and heart rate were also measured. Tests were performed on a dummy head and on two subjects. In some tests a poor face seal was introduced by putting an open tubing with an inner diameter of 2 mm and outer diameter of 3 mm under the sealing edge of the mask. It was found that inward leakage was less than 0.0001% under all conditions as long as facepiece pressure was positive. When facepiece pressure fell below zero, which occurred at inhalation peak flows about 300 L/min, an inward leakage was detected. One subject achieved, at extreme work load, an inhalation peak flow around 450 L/min. These results show that pressure-demand systems should be tested with a breathing machine giving peak flows of at least 300 L/min to ascertain the capability of these systems to maintain positive pressure in the facepiece during hard rescue work.