[Determination of acetylacetone in workplace air by solvent desorption-gas chromatography]

Objective: To establish a method for the determination of acetylacetone in the air of workplace by gas chromatography. Methods: In August 2020, acetylacetone in the air of workplace was collected by silica gel tube, eluted with methanol, separated and detected by gas chromatography with flame ionization detector. The detection limit and precision of the method were also analyzed. Results: The linear range of acetylacetone was 1.95-1950.60 μg/ml with the regression equation of y=0.815x-3.667, and the correlation coefficient was 0.99993. The limit of detection of the method was 0.18 μg/ml and the minimum detection concentration was 0.12 mg/m(3) (collected sample volume was 1.50 L). The within-run precisions were 1.08%-4.11% and the between-run precisions were 1.98%-2.80%. The desorption rates were 99.68%-100.45%. The sealed samples could be kept at least 15 days at room temperature without significant loss. Conclusion: The solvent desorption-gas chromatography method for the determination of acetylacetone has good precision, high sensitivity and simple operation, and is suitable for the determination of acetylacetone in the air of the workplace.

[The method of determination for butyronitrile and isobutyronitrile in the air of workplace by dissolved desorption-gas chromatography]

Objective: To establish a method for the determination of butyronitrile and isobutyronitrile in the air of workplace by gas chromatography. Methods: In March 2020, butyronitrile and isobutyronitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatogram with flame ionization detector, the characteristics of determination of nitrile and isobutyronitrile by gas chromatography were analyzed. Results: The limit of detection for butyronitrile and isobutyronitrile was 0.33 μg/ml. The linear range of butyronitrile determined by this method was 1.60-1600.00 μg/ml, y=2.295x-3.480, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.43%-4.12%, the between-run precisions were 1.72%-3.70%, and the desorption rates were 93.26%-98.41%. The linear range of isobutyronitrile determined by this method was 1.52-1520.00 μg/ml, y=2.208x-0.102, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.52%-3.22%, the between-run precisions were 1.20%-3.82%, and the desorption rates were 96.85%-102.50%. The sealed samples could be stored at least 10 days at room temperature without significant loss. Conclusion: The method has the advantages of good precision, high sensitivity and simple operation. It is suitable for the simultaneous determination of butyronitrile and isobutyronitrile in the air of workplace.

Human torpor: translating insights from nature into manned deep space expedition

During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (T_b ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.

[Determination of thallium in the urine with colloidal palladium as the matrix modifier by graphite furnace atomic absorption Spectrometry]

Objective: To instruct a method of determining thallium in the urine by graphite furnace atomic absorption spectrometry(GF-AAS) with colloidal palladium as the matrix modifier. Methods: Urine samples were first diluted and then determined by GF-AAS with colloidal palladium while using thermal sample injection. Results: The optimum volume of colloidal palladium was 6 μl and the best ashing temperature was 600-800 ℃ while the atomization temperature was 1700-1900 ℃ . This method showed a good linearity relationship when the concentration between 0.33 and 50.0 μg/L while the correlation coefficient of standard curve line was 0.9992, and the detection limit was 0.33 μg/L and the recovery rate was between 92.7% and 102.3% with the intra-day precision in the range of 2.55% to 3.66% and the inter-day precision in the range of 1.77% to 3.85%. Conclusion: This method has the advantages of low detect limit, high sensitivity and good precision, and it can be used in the biological monitoring and emergency detecting of workers exposed to thallium.

[Spatial distribution of occupational disease prevalence in Guangzhou and Foshan city by geographic information system]

Objective: To explore the occupational disease spatial distribution characteristics in Guangzhou and Foshan city in 2006-2013 with Geographic Information System and to provide evidence for making control strategy. Methods: The data on occupational disease diagnosis in Guangzhou and Foshan city from 2006 through 2013 were collected and linked to the digital map at administrative county level with Arc GIS12.0 software for spatial analysis. Results: The maps of occupational disease and Moran's spatial autocor-relation analysis showed that the spatial aggregation existed in Shunde and Nanhai region with Moran's index 1.727, -0.003. Local Moran's I spatial autocorrelation analysis pointed out the "positive high incidence re-gion" and the "negative high incidence region" during 2006~2013. Trend analysis showed that the diagnosis case increased slightly then declined from west to east, increase obviously from north to south, declined from? southwest to northeast, high in the middle and low on both sides in northwest-southeast direction. Conclusions: The occupational disease is obviously geographical distribution in Guangzhou and Foshan city. The corresponding prevention measures should be made according to the geographical distribution.

Acclimation during space flight: effects on human emotion

Recently, studies on the extent to which spaceflight affects the psychology of individuals has received attention. In order to reveal the mental challenges that humans face in space, we need practical viewpoints to integrate the psychological effects, behavior, performance and the environment itself for space exploration. The present review discusses the individual variables related to space psychology and manned spaceflight, in addition to their growing trends. These items include patterns of emotional changes in extreme environments and the approaches to evaluating emotions. Moreover, the review concludes with suggested future research on emotion during spaceflight and its analogs. These data and information are needed to plan for the exploration of the Moon and Mars, along with contributions to the construction of the international space station (ISS) and astronaut training.

Predicting individual brain maturity using dynamic functional connectivity

Neuroimaging-based functional connectivity (FC) analyses have revealed significant developmental trends in specific intrinsic connectivity networks linked to cognitive and behavioral maturation. However, knowledge of how brain functional maturation is associated with FC dynamics at rest is limited. Here, we examined age-related differences in the temporal variability of FC dynamics with data publicly released by the Nathan Kline Institute (NKI; n = 183, ages 7-30) and showed that dynamic inter-region interactions can be used to accurately predict individual brain maturity across development. Furthermore, we identified a significant age-dependent trend underlying dynamic inter-network FC, including increasing variability of the connections between the visual network, default mode network (DMN) and cerebellum as well as within the cerebellum and DMN and decreasing variability within the cerebellum and between the cerebellum and DMN as well as the cingulo-opercular network. Overall, the results suggested significant developmental changes in dynamic inter-network interaction, which may shed new light on the functional organization of typical developmental brains.

Disrupted resting-state functional architecture of the brain after 45-day simulated microgravity

Long-term spaceflight induces both physiological and psychological changes in astronauts. To understand the neural mechanisms underlying these physiological and psychological changes, it is critical to investigate the effects of microgravity on the functional architecture of the brain. In this study, we used resting-state functional MRI (rs-fMRI) to study whether the functional architecture of the brain is altered after 45 days of −6° head-down tilt (HDT) bed rest, which is a reliable model for the simulation of microgravity. Sixteen healthy male volunteers underwent rs-fMRI scans before and after 45 days of −6° HDT bed rest. Specifically, we used a commonly employed graph-based measure of network organization, i.e., degree centrality (DC), to perform a full-brain exploration of the regions that were influenced by simulated microgravity. We subsequently examined the functional connectivities of these regions using a seed-based resting-state functional connectivity (RSFC) analysis. We found decreased DC in two regions, the left anterior insula (aINS) and the anterior part of the middle cingulate cortex (MCC; also called the dorsal anterior cingulate cortex in many studies), in the male volunteers after 45 days of −6° HDT bed rest. Furthermore, seed-based RSFC analyses revealed that a functional network anchored in the aINS and MCC was particularly influenced by simulated microgravity. These results provide evidence that simulated microgravity alters the resting-state functional architecture of the brains of males and suggest that the processing of salience information, which is primarily subserved by the aINS–MCC functional network, is particularly influenced by spaceflight. The current findings provide a new perspective for understanding the relationships between microgravity, cognitive function, autonomic neural function, and central neural activity.

Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: effects of -6° head-down tilt bed rest

Space is characterized by risk and uncertainty. As humans play an important role in long-duration space missions, the ability to make risky decisions effectively is important for astronauts who spend extended time periods in space. The present study used the Balloon Analog Risk Task to conduct both behavioral and fMRI experiments to evaluate the effects of simulated microgravity on individuals' risk-taking behavior and the neural basis of the effect. The results showed that participants' risk-taking behavior was not affected by bed rest. However, we found that the ventromedial prefrontal cortex (VMPFC) showed less deactivation after bed rest and that the VMPFC activation in the active choice condition showed no significant difference between the win outcome and the loss outcome after bed rest, although its activation was significantly greater in the win outcome than in the loss outcome before bed rest. These results suggested that the participants showed a decreased level of value calculation after the bed rest. Our findings can contribute to a better understanding of the effect of microgravity on individual higher-level cognitive functioning.

Keeping the right time in space: importance of circadian clock and sleep for physiology and performance of astronauts

The circadian clock and sleep are essential for human physiology and behavior; deregulation of circadian rhythms impairs health and performance. Circadian clocks and sleep evolved to adapt to Earth's environment, which is characterized by a 24-hour light-dark cycle. Changes in gravity load, lighting and work schedules during spaceflight missions can impact circadian clocks and disrupt sleep, in turn jeopardizing the mood, cognition and performance of orbiting astronauts. In this review, we summarize our understanding of both the influence of the space environment on the circadian timing system and sleep and the impact of these changes on astronaut physiology and performance.

Effect of 45-day simulated microgravity on the evaluation of orally reported emergencies

Accurate evaluation of emergencies is a critical concern in long-duration space flights. Accordingly, we studied the effect of 45 days of - 6° head-down bed rest - a model that simulates the conditions in microgravity environments - on the evaluation of orally reported emergencies. Sixteen male participants listened to corresponding emergency scenarios and assessed the severity of these situations eight times before, during and after bed rest. The results revealed a ' recency effect': compared with emergency descriptions in the order of serious to mild, those framed in the reverse order were judged to be more serious. However, the severity ratings did not vary with time spent in the simulated microgravity environment. These findings are similar to those observed in a regular environment on Earth, indicating that the design principles of information presentation for situations on Earth may also be extended to designs intended for outer space.

PRACTITIONER SUMMARY

A recency effect was found in the evaluation of orally reported emergencies under simulated microgravity conditions. The design principles of information presentation for situations on Earth may also be extended to designs intended for outer space.

Scaling of the low-energy structure in above-threshold ionization in the tunneling regime: theory and experiment

A calculation of the second-order (rescattering) term in the S-matrix expansion of above-threshold ionization is presented for the case when the binding potential is the unscreened Coulomb potential. Technical problems related to the divergence of the Coulomb scattering amplitude are avoided in the theory by considering the depletion of the atomic ground state due to the applied laser field, which is well defined and does not require the introduction of a screening constant. We focus on the low-energy structure, which was observed in recent experiments with a midinfrared wavelength laser field. Both the spectra and, in particular, the observed scaling versus the Keldysh parameter and the ponderomotive energy are reproduced. The theory provides evidence that the origin of the structure lies in the long-range Coulomb interaction.

Classical aspects in above-threshold ionization with a midinfrared strong laser field

We present high resolution photoelectron energy spectra of noble gas atoms from high intensity above-threshold ionization (ATI) at midinfrared wavelengths. An unexpected structure at the very low-energy portion of the spectra, in striking contrast to the prediction of the simple-man theory, has been revealed. A semiclassical model calculation is able to reproduce the experimental feature and suggests the prominent role of the Coulomb interaction of the outgoing electron with the parent ion in producing the peculiar structure in long wavelength ATI spectra.

Semi-nested PCR detection of Babesia orientalis in its natural hosts Rhipicephalus haemaphysaloides and buffalo

Babesiosis has recently been recognized as an emerging infectious disease of buffalo in China. In order to investigate the epidemiology and enzootic potential of this parasite in Hubei province, we sought to develop a semi-nested PCR to detect Babesia orientalis in buffalo and the potential tick vector-Rhipicephalus haemaphysaloides by amplifying a specific 257bp fragment of B. orientalis 18S rRNA gene. The practical limit of detection showed that it had high sensitivity and an approximate parasitemia of 0.00000012% was detected by the PCR system. The blood samples of 121 asymptomatic buffaloes collected from four babesia endemic counties and that of 71 asymptomatic buffaloes collected from three babesia free counties in Hubei province of China were examined for the presence of B. orientalis using both Wright-Giemsa stained blood smear and semi-nested PCR. Microscopic examination revealed that 5/121 animals were positive, whereas 24/121 animals were positive by the semi-nested PCR assay. Of 378 ticks (R. haemaphysaloides) collected from buffaloes and examined by the semi-nested PCR, 35 were positive. The results showed that the semi-nested PCR was a useful method to investigate the epidemiology of buffalo babesiosis (B. orientalis), which is widely distributed in Hubei province, China.

Clinicopathological features, post-surgical survival and prognostic indicators of elderly patients with hepatocellular carcinoma

AIM

Comprehensive data regarding elderly patients with hepatocellular carcinoma (HCC) were limited. The present study aims to widen the knowledge based on patients in China.

METHODS

Fifty-four elderly (> or =65 years) and 125 non-elderly HCC patients undergoing hepatectomy were enrolled in this retrospective study. Clinicopathological features and post-surgical survival were compared between two groups. Prognostic indicators of elderly patients were defined by uni- and multivariate analyses.

RESULTS

Contrast to non-elderly patients, the elderly presented significantly lower rates of HBsAg positivity, Child-Pugh grade A, alpha-fetoprotein (AFP) marked elevation, portal vein tumour thrombosis (PVTT), satellite nodule, and intrahepatic recurrence, smaller tumour sizes, earlier TNM staging and better histological differentiation. No significant differences were found in perioperative mortality rate and post-surgical survival between two groups. PVTT and Edmondson-Steiner grading were identified as independent prognostic indicators of both overall and disease-free survival by multivariate analysis, whereas Child-Pugh grading independently affected the overall survival.

CONCLUSIONS

HCC in the elderly seemed to be less HBV-associated, less progressive and less aggressive than that in the non-elderly. Hepatectomy for the elderly could make a satisfactory prognosis and be well tolerated. Some tumour-related factors independently predict the prognosis of elderly HCC patients, and their liver function status should be further valued.

Sensitivity of 14-3-3 protein test varies in subtypes of sporadic Creutzfeldt-Jakob disease

BACKGROUND

The increase of the 14-3-3 protein in CSF is used as a diagnostic test in Creutzfeldt-Jakob disease (CJD), but the sensitivity and specificity of the 14-3-3 test are disputed. One reason for the dispute may be the recently established heterogeneity of sporadic CJD. The relationship between CSF 14-3-3 protein and sporadic CJD subtypes, distinguished by electrophoretic mobility of proteinase K-resistant prion protein (PrP(Sc)) and genotype at codon 129 of the prion protein gene, has not been elucidated.

METHODS

The authors examined the 14-3-3 protein test in 90 patients with sporadic CJD. PrP(Sc) type (type 1 or type 2) and the genotype at polymorphic codon 129 were determined in each patient. Mutations were excluded by prion gene sequencing.

RESULTS

The authors' findings indicate that the sensitivity of the 14-3-3 test is higher in patients with molecular features of the classic sporadic CJD than in patients with the nonclassic CJD subtypes. The difference appears to be related to the PrP(Sc) type and not to the codon 129 genotype. Disease duration before 14-3-3 testing might also have an influence because it was shorter in classic sporadic CJD.

CONCLUSION

The Creutzfeldt-Jakob disease clinical subtype should be considered when interpreting results of the 14-3-3 test.

Resonance acceleration of electrons in combined strong magnetic fields and intense laser fields

The acceleration mechanism of electrons in combined strong axial magnetic fields and circularly polarized laser pulse fields is investigated by solving the dynamical equations for relativistic electrons both numerically and analytically. We find that the electron acceleration depends not only on the laser intensity, but also on the ratio between electron Larmor frequency and laser frequency. As the ratio approaches unity, a clear resonance peak is observed, corresponding to the laser-magnetic resonance acceleration. Away from the resonance regime, the strong magnetic fields still affect the electron acceleration dramatically. We derive an approximate analytical solution of the relativistic electron energy in adiabatic limit, which provides a full understanding of this phenomenon. Application of our theory to fast ignition of inertial confinement fusion is discussed.

Insomnia associated with thalamic involvement in E200K Creutzfeldt-Jakob disease

BACKGROUND

Insomnia with predominant thalamic involvement and minor cortical and cerebellar pathologic changes is not characteristic of familial Creutzfeldt-Jakob disease (CJD) but is a hallmark of fatal familial insomnia.

OBJECTIVE

To report a 53-year-old woman with intractable insomnia as her initial symptom of disease.

METHODS

The authors characterized clinical, pathologic, and molecular features of the disease using EEG, polysomnography, neurohistology, Western blotting, protein sequencing, and prion protein (PrP) gene (PRNP) analysis.

RESULTS

The patient developed dysgraphia, dysarthria, bulimia, myoclonus, memory loss, visual hallucinations, and opisthotonos, as well as pyramidal, extrapyramidal, and cerebellar signs. Polysomnographic studies showed an absence of stages 3 and 4, and REM. She died 8 months after onset. On neuropathologic examination, there was major thalamic involvement characterized by neuronal loss, spongiform changes, and prominent gliosis. The inferior olivary nuclei exhibited chromatolysis, neuronal loss, and gliosis. Spongiform changes were mild in the neocortex and not evident in the cerebellum. PrP immunopositivity was present in these areas as well as in the thalamus. PRNP analysis showed the haplotype E200K-129M. Western blot analysis showed the presence of proteinase K (PK)-resistant PrP (PrP(sc)) with the nonglycosylated isoform of approximately 21 kd, corresponding in size to that of type 1 PrP(sc). N-terminal protein sequencing demonstrated PK cleavage sites at glycine (G) 82 and G78, as previously reported in CJD with the E200K-129 M haplotype.

CONCLUSIONS

Insomnia may be a prominent early symptom in cases of CJD linked to the E200K-129M haplotype in which the thalamus is severely affected.

Aberrant metal binding by prion protein in human prion disease

Human prion diseases are characterized by the conversion of the normal prion protein (PrP(C)) into a pathogenic isomer (PrP(Sc)). Distinct PrP(Sc) conformers are associated with different subtypes of prion diseases. PrP(C) binds copper and has antioxidation activity. Changes in metal-ion occupancy can lead to significant decline of the antioxidation activity and changes in conformation of the protein. We studied the trace element status of brains from patients with sporadic Creutzfeldt-Jakob disease (sCJD). We found a decrease of up to 50% of copper and an increase in manganese of approximately 10-fold in the brain tissues from sCJD subjects. We have also studied the metal occupancy of PrP in sCJD patients. We observed striking elevation of manganese and, to a lesser extent, of zinc accompanied by significant reduction of copper bound to purified PrP in all sCJD variants, determined by the PrP genotype and PrP(Sc) type, combined. Both zinc and manganese were undetectable in PrP(C) preparations from controls. Copper and manganese changes were pronounced in sCJD subjects homozygous for methionine at codon 129 and carrying PrP(Sc) type-1. Anti-oxidation activity of purified PrP was dramatically reduced by up to 85% in the sCJD variants, and correlated with increased in oxidative stress markers in sCJD brains. These results suggest that altered metal-ion occupancy of PrP plays a pivotal role in the pathogenesis of prion diseases. Since the metal changes differed in each sCJD variants, they may contribute to the diversity of PrP(Sc) and disease phenotype in sCJD. Finally, this study also presented two potential approaches in the diagnosis of CJD; the significant increase in brain manganese makes it potentially detectable by MRI, and the binding of manganese by PrP in sCJD might represent a novel diagnostic marker.

The management of white phosphorus burns

Phosphorus burns are a rarely encountered chemical burn, typically occurring in battle, industrial accidents, or from fireworks. Death may result even with minimal burn areas. Early recognition of affected areas and adequate resuscitation is crucial. Amongst our 2765 admissions between 1984 and 1998, 326 patients had chemical burns. Seven admissions were the result of phosphorus burns. Our treatment protocol comprises 1% copper sulfate solution for neutralization and identification of phosphorus particles, copious normal saline irrigation, keeping wounds moist with saline-soaked thick pads even during transportation, prompt debridement of affected areas, porcine skin coverage or skin grafts for acute wound management, as well as intensive monitoring of electrolytes and cardiac function in our burns center. Intravenous calcium gluconate is mandatory for correction of hypocalcemia. Of the seven, one patient died from inhalation injury and the others were scheduled for sequential surgical procedures for functional and cosmetic recovery. Cooling affected areas with tap water or normal saline, prompt removal of phosphorus particles with mechanical debridement, intensive monitoring, and maintenance of electrolyte balance are critical steps in initial management. Fluid resuscitation can be adjusted according to urine output. Early excision and skin autografts summarize our phosphorus burn treatment protocol.

Reconstruction of burn scar of the upper extremities with artificial skin

The management of upper-extremity burn contractures is a major challenge for plastic surgeons. After approval by the Food and Drug Administration, artificial skin (Integra) has been available in Taiwan since 1997. From January of 1997 to July of 1999, the authors applied artificial skin to 13 severely burned patients for the reconstruction of their upper extremities, resulting in an increased range of motion in the upper-extremity joints and improved skin quality. An additional benefit was the rapid reepithelialization of the donor sites. There were no complications of infection throughout the therapeutic course, and the overall results were satisfactory. During the 2-year study, scar condition was monitored between 8 and 24 months, and a good appearance and pliable skin were obtained according to the Vancouver Scar Scale. According to this evaluation of Oriental skin turgor, normal pigmentation was restored about 6 months after the resurfacing procedure. For patients with severe burns in whom there is insufficient available skin for a full-thickness skin graft or another appropriate flap for scar revision, Integra is an alternative. The two major concerns in dealing with artificial skin are (1) a 10- to 14-day waiting period for maturation of the neo-dermis, necessitating a two-stage operation, and (2) prevention of infection with antibiotics and meticulous wound care.

Absence of protease-resistant prion protein in the cerebrospinal fluid of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD), believed to be caused by a protease-resistant isoform of prion protein (PrP(Sc)), usually manifests itself as a clinically distinctive age-related dementia because of its rapid progression, occasionally accompanied by cerebellar ataxia. Recently, a variant CJD (vCJD) has been described, which has prominent early psychiatric symptoms and an earlier age of death. Although cerebrospinal fluid (CSF) is part of the extracellular fluid of the central nervous system (CNS), the bulk of its proteins are derived from the plasma and there is increasing concern about possible transmission of prion disease by blood. As investigation of CSF has played a significant role in the diagnosis and management of several neurological diseases, it was decided to characterize PrP present in the CSF of CJD individuals. Significant variation was observed in the level of PrP in the CSF from both non-CJD and CJD (including vCJD) patients, and the detected PrP forms are protease-sensitive. Using a conformation-dependent immunoassay, it was further demonstrated that the PrP detected in the CSF from CJD patients was broadly similar in conformation to that found in non-CJD patients. Taken together, the results of this study fail to demonstrate any correlation between the presence of protease-resistant PrP isoform (PrP(Sc)) in the CSF and disease manifestation.

PrP(Sc) typing by N-terminal sequencing and mass spectrometry

The heterogeneity of the clinicopathological phenotype in human prion diseases is associated with the presence of the different forms of the abnormal prion protein, PrP(Sc). We have previously shown that PrP(Sc) in FFI and a subtype of familial CJD linked to the D178N mutation can be distinguished by their difference in gel mobility following proteinase K (PK) treatment. To further characterize the structural difference of PrP(Sc) in familial prion diseases, N-terminal sequencing and mass spectrometry were used to identify the protease cleavage sites in PrP(Sc) extracted from affected brains. We found that the main PK cleavage sites of PrP(Sc) are located at residue 97 in FFI, and residue 82 in both CJD178 and a GSS subtype linked to the P102L mutation. The differential accessibility to protease in the native PrP(Sc) suggests that PrP(Sc) exist as distinct conformers in different disease states.

Induction of HO-1 and NOS in doppel-expressing mice devoid of PrP: implications for doppel function

Ectopic expression of the doppel (Dpl) protein, a homologue of the prion protein (PrP), was recently associated with cerebellar Purkinje cell degeneration observed in two aging prion protein knock-out (Prnp(0/0)) mouse lines. We investigated the possible role of Dpl in oxidative metabolism. Two Prnp(0/0) mouse lines of similar genetic background were studied. One line expresses Dpl in the brain and displays Dpl-associated cerebellar abnormalities. The other has no elevated expression of Dpl and no cerebellar abnormalities. We observed a correlation between Dpl expression and the induction of both heme oxygenase 1 (HO-1) and nitric oxide synthase systems (nNOS and iNOS). These responses are suggestive of increased oxidative stress in the brains of the Dpl-expressing Prnp(0/0) mice. No induction was observed with Hsp-60, indicating a specific response by the HO/NOS system. We proposed that Dpl expression exacerbates oxidative damage that is antagonistic to the protective function of wild-type PrP.

Expression and structural characterization of the recombinant human doppel protein

The doppel protein (Dpl) is a newly recognized prion protein (PrP)-like molecule encoded by a novel gene locus, prnd, located on the same chromosome as the PrP gene. To study the structural features of Dpl, we have expressed recombinant human Dpl corresponding to the putative mature protein domain (residues 24-152) in Escherichia coli. The primary structure of the recombinant Dpl 24-152 was characterized using gel electrophoresis, N-terminal Edman sequencing, matrix-assisted laser desorption ionization mass spectrometry, and electrospray ionization mass spectrometry. Dpl 24-152 was shown to contain two disulfide bonds (Cys94-Cys145 and Cys108-Cys140). The secondary structure of Dpl was analyzed using far-UV circular dichroism spectroscopy. Dpl 24-152 was found to be an alpha-helical protein having a high helical content (40%). Dpl 24-152 exhibited characteristics of a thermodynamically stable protein that undergoes reversible and cooperative thermal denaturation. In addition, Dpl was found to be soluble and sensitive to proteinase K digestion. Therefore, Dpl 24-152 possesses biochemical properties similar to those of recombinant PrP. This study provides knowledge about the molecular features of human Dpl that will be useful in further investigation into its normal function and the role it may play in neurodegenerative diseases.

Free microvascular transfer of the acromiotrapezius osteomuscular flap in rats

The acromiotrapezius-scapular spine osteomuscular flap is a new osteomuscular research model for use in microvascular free tissue transfer in rats. We performed anatomical studies to collect data on muscle weight, dimension, vessel calibre and bone size in 20 flaps. This flap has a triangular shape with an average size of 38 x 39 x 32 mm and an average weight of 1.25 g; the scapular spine of 20 mm in average length can be harvested with the flap. The pedicle can be taken in continuity with the cervical trunk (average diameter of artery and vein were 0.5 mm and 0.6mm, respectively, with an average pedicle length of 12 mm). The flap was harvested and transferred to the groin area of the same rat and anastomosed to the superficial epigastric vessels. Fifteen transplantations were performed and the 7-day flap survival was 93.3%. The acromiotrapezius flap is believed to be a new and reliable osteomuscular model in the rat.

The boomerang flap in managing injuries of the dorsum of the distal phalanx

Finding an appropriate soft-tissue grafting material to close a wound located over the dorsum of a finger, especially the distal phalanx, can be a difficult task. The boomerang flap mobilized from the dorsum of the proximal phalanx of an adjacent digit can be useful when applied as an island pedicle skin flap. The vascular supply to the skin flap is derived from the retrograde perfusion of the dorsal digital artery. Mobilization and lengthening of the vascular pedicle are achieved by dividing the distal end of the dorsal metacarpal artery at the bifurcation and incorporating two adjacent dorsal digital arteries into one. The boomerang flap was used in seven individuals with injuries involving the dorsal aspect of the distal phalanx over the past year. Skin defects in all patients were combined with bone,joint, or tendon exposure. The authors found that the flap was reliable and technically simple to design and execute. This one-step procedure preserves the proper palmar digital artery to the fingertip and has proven valuable for the coverage of wide and distal defects because it has the advantages of an extended skin paddle and a lengthened vascular pedicle. When conventional local flaps are inadequate, the boomerang flap should be considered for its reliability and low associated morbidity.

Genetic influence on the structural variations of the abnormal prion protein

Prion diseases are characterized by the presence of the abnormal prion protein PrP(Sc), which is believed to be generated by the conversion of the alpha-helical structure that predominates in the normal PrP isoform into a beta-sheet structure resistant to proteinase K (PK). In human prion diseases, two major types of PrP(Sc), type 1 and 2, can be distinguished based on the difference in electrophoretic migration of the PK-resistant core fragment. In this study, protein sequencing was used to identify the PK cleavage sites of PrP(Sc) in 36 cases of prion diseases. We demonstrated two primary cleavage sites at residue 82 and residue 97 for type 1 and type 2 PrP(Sc), respectively, and numerous secondary cleavages distributed along the region spanning residues 74-102. Accordingly, we identify three regions in PrP(Sc): one N-terminal (residues 23-73) that is invariably PK-sensitive, one C-terminal (residues 103-231) that is invariably PK-resistant, and a third variable region (residues 74-102) where the site of the PK cleavage, likely reflecting the extent of the beta-sheet structure, varies mostly as a function of the PrP genotype at codon 129.

Cloning of amadoriase I isoenzyme from Aspergillus sp.: evidence of FAD covalently linked to Cys342

Amadoriases are a novel class of FAD enzymes which catalyze the oxidative deglycation of glycated amino acids to yield corresponding amino acids, glucosone, and H(2)O(2). We previously reported the purification and characterization of two amadoriase isoenzymes from Aspergillus fumigatus and the molecular cloning of amadoriase II. To identify the primary structure of amadoriase I, we prepared a cDNA library from Aspergillus fumigatus and isolated a clone using a probe amplified by polymerase chain reaction with primers designed according to the partial amino acid sequences from peptide mapping. The primary structure of the enzyme deduced from the nucleotide sequence comprises 445 amino acid residues. The enzyme contains 1 mol of FAD as a cofactor, which is covalently linked to Cys342, as determined by mutagenesis analysis, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and electrospray ionization-collisional-activated dissociation tandem mass spectrometry. Sequence alignment studies show that amadoriase I has 22% homology with monomeric sarcosine oxidase in which FAD is also linked to a homologous Cys residue. Amadoriases are of potential importance as tools for uncoupling hyperglycemia and glycation reactions that are thought to play a role in diabetic complications.

Aggregation and fibrillization of the recombinant human prion protein huPrP90-231

According to the "protein-only" hypothesis, the critical step in the pathogenesis of prion diseases is the conformational transition between the normal (PrP(C)) and pathological (PrP(Sc)) isoforms of prion protein. To gain insight into the mechanism of this transition, we have characterized the biophysical properties of the recombinant protein corresponding to residues 90-231 of the human prion protein (huPrP90-231). Incubation of the protein under acidic conditions (pH 3.6-5) in the presence of 1 M guanidine-HCl resulted in a time-dependent transition from an alpha-helical conformation to a beta-sheet structure and oligomerization of huPrP90-231 into large molecular weight aggregates. No stable monomeric beta-sheet-rich folding intermediate of the protein could be detected in the present experiments. Kinetic analysis of the data indicates that the formation of beta-sheet structure and protein oligomerization likely occur concomitantly. The beta-sheet-rich oligomers were characterized by a markedly increased resistance to proteinase K digestion and a fibrillar morphology (i.e., they had the essential physicochemical properties of PrP(Sc)). Contrary to previous suggestions, the conversion of the recombinant prion protein into a PrP(Sc)-like form could be accomplished under nonreducing conditions, without the need to disrupt the disulfide bond. Experiments in urea indicate that, in addition to acidic pH, another critical factor controlling the transition of huPrP90-231 to an oligomeric beta-sheet structure is the presence of salt.

Free vascularized fibular bone flap in the rat

Free vascularized fibula bone flap has been widely used in reconstruction of the mandible, long segment defect, congenital pseudarthroses, and osteomyelitis. Such applications stirred an interest in basic studies of bone biology, bone healing process, and incorporation of recipient bone defect. An experimental free vascularized fibula rat model is presented here for such investigations. We performed 16 angiograms and anatomic dissections in eight rats for collecting data on fibular length, blood supply, and the caliber of significant vessels. The fibula was harvested with part of the flexor hallucis longus muscle with an average length of 28 mm. The pedicle can be taken in continuity with the popliteal vessels (average diameter of 0.8 mm and 0.9 mm of artery and vein, respectively, with an average pedicle length of 14 mm). This vascularized fibula bone was harvested and transferred to the groin area of the same rat and anastomosed to the saphenous vessels. Twelve transplantations were performed, with a 7-day flap survival rate of 100%. The free fibula vascularized bone flap in the rat is a reliable model for further investigations.

Prolonged perivascular use of verapamil or lidocaine decreases skin flap necrosis

During this experiment the authors investigated whether prolonged local use of verapamil or lidocaine prevents vasoconstriction and establishes better blood supply to the rat epigastric skin flap, hence reducing the necrosis that occurs otherwise. Abdominal wall skin flaps of 45 Sprague-Dawley rats, based on a single pedicle of the femoral vessels, were elevated. A subcutaneous pocket for the microport valve was created, and the adjacent catheter tip was sewn next to the femoral vessels. In the control and the two treatment groups, 0.5 ml saline or vasodilator solution respectively was injected through the microport every 12 hours for 5 days. On postoperative day 5 there was no statistical difference between the flap surfaces in all groups. The area of flap necrosis was significantly lower in the verapamil- (p = 0.001) and the lidocaine-treated (p = 0.012) groups vs. the control group as determined by analysis of variance with Bonferroni's post hoc test. In conclusion, topical application of verapamil and lidocaine solutions for 5 postoperative days decreased flap marginal necrosis significantly. Prolonged injection of vasodilators in the vicinity of the vascular pedicle prevents vasospasm and improves blood supply to the flap.

Patterns of flap loss related to arterial and venous insufficiency in the rat pedicled TRAM flap

Vascular supply to the contralateral portion of the conventional transverse rectus abdominis musculocutaneous (TRAM) flap (zone IV) may become compromised, resulting in partial flap loss and requiring segmental excision. The etiology of this necrosis is not clear. This study determines skin necrosis patterns on a superiorly pedicled caudal TRAM flap during conditions of venous and arterial insufficiency, and determines whether cutaneous venous outflow can sustain a flap with venous insufficiency. Twenty-eight adult male Sprague-Dawley rats underwent superior pedicled TRAM flap elevation, and the zones were marked on the skin paddle. The animals were divided into four groups: control (group A, N = 6), arterial ligation (group B, N = 6), venous ligation (group C, N = 8), and venous ligation with cutaneous venous outflow (group D, N = 8). After 10 days, the skin paddle was photographed and the areas of necrotic skin were measured. Results showed that group B (selective arterial ligation) had 51.7 +/- 2.8% and 40.0 +/- 2.0% skin necrosis in zones I and II respectively. Zone I necrosis was significantly greater in group B compared with the control (p < 0.05). Group C (selective venous ligation) resulted in 73.8 +/- 16.4% and 93.8 +/- 33.4% skin necrosis in zones III and IV respectively. This necrosis was significantly greater compared with the control (p < 0.001). Group D rats' lateral skin necrosis compared significantly less with group C (p < 0.001). These results demonstrate that the patterns of flap necrosis in rat TRAM flaps with poor arterial inflow differ from those with venous stasis. Necrosis of the contralateral portion (zone IV) of human TRAM flaps may be related to problems with venous stasis; thus, a cutaneous venous outflow may prevent this problem.

Tau gene mutation in familial progressive subcortical gliosis

Familial forms of frontotemporal dementias are associated with mutations in the tau gene. A kindred affected by progressive subcortical gliosis (PSG), a rare form of presenile dementia, has genetic linkage to chromosome 17q21-22. This kindred (PSG-1) is included in the 'frontotemporal dementias and Parkinsonism linked to chromosome 17' group along with kindreds affected by apparently different forms of atypical dementias. Some of these kindreds have mutations in the tau gene. We report here that PSG-1 has a tau mutation at position +16 of the intron after exon 10. The mutation destabilizes a predicted stem-loop structure and leads to an over-representation of the soluble four-repeat tau isoforms, which assemble into wide, twisted, ribbon-like filaments and ultimately result in abundant neuronal and glial tau pathology. The mutations associated with PSG and other atypical dementias can be subdivided into three groups according to their tau gene locations and effects on tau. The existence of tau mutations with distinct pathogenetic mechanisms may explain the phenotypic heterogeneity of atypical dementias that previously led to their classification into separate disease entities.

The comparison of early fluid therapy in extensive flame burns between inhalation and noninhalation injuries

Over the last half century, advances in treatment have changed the principal cause of death in burn patients from burn shock and wound sepsis to pulmonary sepsis, of which inhalation injury has always played a key role in morbidity and mortality. Even though Navar et al., Am. J. Surg. 1985;150:716-720 have noted that patients with inhalation injury had a mean fluid requirement of 5.8 ml/kg/% burn to achieve resuscitation from early burn shock, while patients without inhalation injury required only a mean fluid of 4.0 ml/kg/% burn, to achieve successful resuscitation in inhalation injured patients with minimum but adequate fluid has always been a challenge. To further define the difference of early fluid therapy between inhalation and noninhalation in extensively burned patients, a retrospective analysis was carried out in the Tri-Service General Hospital. Sixty-two flame burned patients (aged from 16 to 81 years-old with a mean age of 33.2+/-15.1 years: with burn size ranging from 30% to 98% TBSA with a mean burn size of 60.5+/-22.7%; 26 with inhalation injury; noninhalation 36) were reviewed during a 5-year period. The Parkland formula is the initial choice of fluid regimen with 4 ml/kg/% burn and the amount of replacement is monitored by urine output and is titrated to maintain urine output between 0.5 and 1.0 ml/kg/h. The mean amounts of fluid requirements of both inhalation and noninhalation burned patients were 3.1 +/- 1.0 and 2.3+/-0.8 ml/kg/% burn respectively (p < 0.05). Our study showed less fluid requirement for both inhalation and noninhalation injured patients in comparison with the Navar study and Parkland predictions in the first 24 h postburn. Furthermore, the inhalation injured patients definitely required volumes of fluid in excess of those required in noninhalation injured cases.

Inflammatory pseudotumor of the liver in a patient with human immunodeficiency virus infection

A 31 year-old male was admitted for investigation of a hepatic tumor, which was incidentally found during abdominal sonography. Abdominal ultrasound revealed a large heterogeneous hyperechoic mass, 4x6x5cm in size, located at the inferior portion of the medial segment of the liver. Abdominal computed tomography without enhancement showed a hepatic tumor, 6 cm in size, in the medial segment of the liver. Malignancy was suspected in the light of radiological presentation. Therefore, wedge resection of the hepatic tumor was performed. The pathological findings revealed that the hepatic tumor was composed of dense fibrous tissue, plump spindle cells, foamy histiocytes, abundant lymphocytes, plasma cells and macrophages which led to the diagnosis of inflammatory tumor of the liver. The post-operative course was uneventful, and the patient was discharged two weeks after operation. Unfortunately, high fever and persisting headache were noted one week after discharge, thus the patient was re-admitted. The infectious focus was investigated during the second admission. Serological test for anti-human immunodeficiency virus was positive. Computed tomography of the brain revealed inflammatory changes over the territory of right middle cerebral artery. The patient died two weeks after the onset of encephalitis. We believe this to be the first case of inflammatory pseudotumor of the liver associated with human immunodeficiency virus infection.

Different patterns of truncated prion protein fragments correlate with distinct phenotypes in P102L Gerstmann-Sträussler-Scheinker disease

The clinicopathological phenotype of the Gerstmann-Sträussler-Scheinker disease (GSS) variant linked to the codon 102 mutation in the prion protein (PrP) gene (GSS P102L) shows a high heterogeneity. This variability also is observed in subjects with the same prion protein gene PRNP haplotype and is independent from the duration of the disease. Immunoblot analysis of brain homogenates from GSS P102L patients showed two major protease-resistant PrP fragments (PrP-res) with molecular masses of approximately 21 and 8 kDa, respectively. The 21-kDa fragment, similar to the PrP-res type 1 described in Creutzfeldt-Jakob disease, was found in five of the seven subjects and correlated with the presence of spongiform degeneration and "synaptic" pattern of PrP deposition whereas the 8-kDa fragment, similar to those described in other variants of GSS, was found in all subjects in brain regions showing PrP-positive multicentric amyloid deposits. These data further indicate that the neuropathology of prion diseases largely depends on the type of PrP-res fragment that forms in vivo. Because the formation of PrP-res fragments of 7-8 kDa with ragged N and C termini is not a feature of Creutzfeldt-Jakob disease or fatal familial insomnia but appears to be shared by most GSS subtypes, it may represent a molecular marker for this disorder.

Molecular pathology of fatal familial insomnia

Fatal familial insomnia (FFI) is linked to a mutation at codon 178 of the prion protein gene, coupled with the methionine codon at position 129, the site of a methionine/valine polymorphism. The D178N mutation coupled with the 129 valine codon is linked to a subtype of Creutzfeldt-Jakob disease (CJD178) with a different phenotype. Two protease resistant fragments of the pathogenic PrP (PrPres), which differ in molecular mass, are associated with FFI and CJD178, respectively, suggesting that the two PrPres have different conformations and hence they produce different disease phenotypes. FFI transmission experiments, which show that the endogenous PrPres recovered in affected syngenic mice specifically replicates the molecular mass of the FFI PrPres inoculated and is associated with a phenotype distinct from that of the CJD178 inoculated mice, support this idea. The second distinctive feature of the FFI PrPres is the underrepresentation of the unglycosylated PrPres form. Cell models indicate that the underrepresentation of this PrPres form results from the PrP dysmetabolism caused by the D178N mutation and not from the preferential conversion of the glycosylated forms. Codon 129 on the normal allele further modifies the FFI phenotype determining patient subpopulations of 129 homozygotes and heterozygotes: disease duration is generally shorter, insomnia more severe and histopathology more restricted to the thalamus in the homozygotes than in the heterozygotes. The allelic origin of PrPres fails to explain this finding since in both cases FFI PrPres is expressed only by the mutant allele. Despite remarkable advances, many issues remain unsolved precluding full understanding of the FFI pathogenesis.

Protective effects of free radical inhibitors in intracerebral hemorrhage in rat

Iron compounds formed in the degradation of a hematoma can accelerate the formation of free radicals in adjacent ischemic or hypoperfused tissue. The purpose of this study was to examine the efficacy of compounds that quench free radicals in improving the outcome in rats with experimental intracerebral hemorrhage. Intracerebral hemorrhage was induced in rats by injection of bacterial collagenase and heparin into the caudate nucleus. Rats were treated with alpha-tocopherol plus ascorbic acid starting before hemorrhage, or with dimethylthiourea or alpha-phenyl-N-tert-butyl nitrone starting 2 h after hemorrhage, with treatment continued for 10 days after induction of hemorrhage. Outcome was assessed by behavioral analyses, magnetic resonance imaging, and histopathology. A trend towards behavioral improvement was found for rats treated with alpha-tocopherol/ascorbic acid, while behavior was significantly improved following intracerebral hemorrhage in rats treated with dimethylthiourea or alpha-phenyl-N-tert-butyl nitrone. These results suggest that free radicals may play a role in the development of brain injury following intracerebral hemorrhage, and that compounds that interrupt the free radical cascade may improve outcome. However, treatment did not significantly affect edema, resolution of the hematoma, or neuronal injury in tissue adjacent to the hemorrhage.

Skin injury in the operating room

Skin injury occurring in the operating room may occur as a result of electrical current, thermal injury, chemical irritation and mechanical stress. Between 1 December 1996 and 28 February 1997, 19 cases of skin injury from a total of 3657 operations were noted in our hospital. These injuries tend to be ignored because of their early spontaneous healing. We suggest that medical staff should pay more attention to this complication and prevent it from occurring.

Prion protein aggregation reverted by low temperature in transfected cells carrying a prion protein gene mutation

Prion diseases are characterized by the conversion of the normal cellular prion protein (PrPC), a glycoprotein that is anchored to the cell membrane by a glycosylphosphatidylinositol moiety, into an isoform that is protease-resistant (PrPres) and pathogenic. In inherited prion diseases, mutations in the prion protein (PrPM) engender the conversion of PrPM into PrPres. We developed a cell model of Gerstmann-Sträussler-Scheinker disease, a neurodegenerative condition characterized by PrPM-containing amyloid deposits and neuronal loss, by expressing the Gerstmann-Sträussler-Scheinker haplotype Q217R-129V in human neuroblastoma cells. By comparison to PrPC, this genotype results in the following alterations of PrPM: 1) expression of an aberrant form lacking the glycosylphosphatidylinositol anchor, 2) increased aggregation and protease resistance, and 3) impaired transport to the cell surface. Most of these alterations are temperature-sensitive, indicating that they are due to misfolding of PrPM.

Allelic origin of the abnormal prion protein isoform in familial prion diseases

The hallmark of prion diseases is the presence of an aberrant isoform of the prion protein (PrP(res)) that is insoluble in nondenaturing detergents and resistant to proteases. We investigated the allelic origin of PrP(res) in brains of subjects heterozygous for the D178N mutation linked to fatal familial insomnia (FFI) and a subtype of Creutzfeldt-Jakob disease (CJD178), as well as for insertional mutations associated with another CJD subtype. We found that in FFI and CJD178 subjects, only mutant PrP was detergent-insoluble and protease-resistant. Therefore, PrP(res) derives exclusively from the mutant allele carrying the D178N mutation. In contrast, in the CJD subtype harboring insertional mutations, wild-type PrP was also detergent-insoluble and likely to be protease-resistant. Our findings indicate that the participation of the wild-type PrP in the formation of PrP(res) depends on the type of mutations, providing an insight into the molecular mechanisms underlying the phenotypic heterogeneity in familial prion diseases.

Molecular assessment of the potential transmissibilities of BSE and scrapie to humans

More than a million cattle infected with bovine spongiform encephalopathy (BSE) may have entered the human food chain. Fears that BSE might transmit to man were raised when atypical cases of Creutzfeldt-Jakob disease (CJD), a human transmissible spongiform encephalopathy (TSE), emerged in the UK. In BSE and other TSE diseases, the conversion of the protease-sensitive host prion protein (PrP-sen) to a protease-resistant isoform (PrP-res) is an important event in pathogenesis. Biological aspects of TSE diseases are reflected in the specificities of in vitro PrP conversion reactions. Here we show that there is a correlation between in vitro conversion efficiencies and known transmissibilities of BSE, sheep scrapie and CJD. On this basis, we used an in vitro system to gauge the potential transmissibility of scrapie and BSE to humans. We found limited conversion of human PrP-sen to PrP-res driven by PrP-res associated with both scrapie (PrP[Sc]) and BSE (PrP[BSE]). The efficiencies of these heterologous conversion reactions were similar but much lower than those of relevant homologous conversions. Thus the inherent ability of these infectious agents of BSE and scrapie to affect humans following equivalent exposure may be finite but similarly low.