Clinical characteristics of COVID-19-infected cancer patients: a retrospective case study in three hospitals within Wuhan, China

Background

Cancer patients are regarded as a highly vulnerable group in the current Coronavirus Disease 2019 (COVID-19) pandemic. To date, the clinical characteristics of COVID-19-infected cancer patients remain largely unknown.

Patients and methods

In this retrospective cohort study, we included cancer patients with laboratory-confirmed COVID-19 from three designated hospitals in Wuhan, China. Clinical data were collected from medical records from 13 January 2020 to 26 February 2020. Univariate and multivariate analyses were carried out to assess the risk factors associated with severe events defined as a condition requiring admission to an intensive care unit, the use of mechanical ventilation, or death.

Results

A total of 28 COVID-19-infected cancer patients were included; 17 (60.7%) patients were male. Median (interquartile range) age was 65.0 (56.0–70.0) years. Lung cancer was the most frequent cancer type (n = 7; 25.0%). Eight (28.6%) patients were suspected to have hospital-associated transmission. The following clinical features were shown in our cohort: fever (n = 23, 82.1%), dry cough (n = 22, 81%), and dyspnoea (n = 14, 50.0%), along with lymphopaenia (n = 23, 82.1%), high level of high-sensitivity C-reactive protein (n = 23, 82.1%), anaemia (n = 21, 75.0%), and hypoproteinaemia (n = 25, 89.3%). The common chest computed tomography (CT) findings were ground-glass opacity (n = 21, 75.0%) and patchy consolidation (n = 13, 46.3%). A total of 15 (53.6%) patients had severe events and the mortality rate was 28.6%. If the last antitumour treatment was within 14 days, it significantly increased the risk of developing severe events [hazard ratio (HR) = 4.079, 95% confidence interval (CI) 1.086–15.322, P = 0.037]. Furthermore, patchy consolidation on CT on admission was associated with a higher risk of developing severe events (HR = 5.438, 95% CI 1.498–19.748, P = 0.010).

Conclusions

Cancer patients show deteriorating conditions and poor outcomes from the COVID-19 infection. It is recommended that cancer patients receiving antitumour treatments should have vigorous screening for COVID-19 infection and should avoid treatments causing immunosuppression or have their dosages decreased in case of COVID-19 coinfection.

A viral gene that activates lytic cycle expression of Kaposi's sarcoma-associated herpesvirus

Herpesviruses exist in two states, latency and a lytic productive cycle. Here we identify an immediate-early gene encoded by Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus eight (HHV8) that activates lytic cycle gene expression from the latent viral genome. The gene is a homologue of Rta, a transcriptional activator encoded by Epstein-Barr virus (EBV). KSHV/Rta activated KSHV early lytic genes, including virus-encoded interleukin 6 and polyadenylated nuclear RNA, and a late gene, small viral capsid antigen. In cells dually infected with Epstein-Barr virus and KSHV, each Rta activated only autologous lytic cycle genes. Expression of viral cytokines under control of the KSHV/Rta gene is likely to contribute to the pathogenesis of KSHV-associated diseases.

LIGHT, a novel ligand for lymphotoxin beta receptor and TR2/HVEM induces apoptosis and suppresses in vivo tumor formation via gene transfer

LIGHT is a new member of tumor necrosis factor (TNF) cytokine family derived from an activated T cell cDNA library. LIGHT mRNA is highly expressed in splenocytes, activated PBL, CD8(+) tumor infiltrating lymphocytes, granulocytes, and monocytes but not in the thymus and the tumor cells examined. Introduction of LIGHT cDNA into MDA-MB-231 human breast carcinoma caused complete tumor suppression in vivo. Histological examination showed marked neutrophil infiltration and necrosis in LIGHT expressing but not in the parental or the Neo-transfected MDA-MB-231 tumors. Interferon gamma (IFNgamma) dramatically enhances LIGHT-mediated apoptosis. LIGHT protein triggers apoptosis of various tumor cells expressing both lymphotoxin beta receptor (LTbetaR) and TR2/HVEM receptors, and its cytotoxicity can be blocked specifically by addition of a LTbetaR-Fc or a TR2/HVEM-Fc fusion protein. However, LIGHT was not cytolytic to the tumor cells that express only the LTbetaR or the TR2/HVEM or hematopoietic cells examined that express only the TR2/HVEM, such as PBL, Jurkat cells, or CD8(+) TIL cells. In contrast, treatment of the activated PBL with LIGHT resulted in release of IFNgamma. Our data suggest that LIGHT triggers distinct biological responses based on the expression patterns of its receptors on the target cells. Thus, LIGHT may play a role in the immune modulation and have a potential value in cancer therapy.

Relative mortality and survival in multiple sclerosis: findings from British Columbia, Canada

OBJECTIVE

To examine mortality and factors associated with survival in a population based multiple sclerosis (MS) cohort.

METHODS

Clinical and demographic data of MS patients registered with the British Columbia MS clinics (1980-2004) were linked to provincial death data, and patients were followed until death, emigration or study end (31 December 2007). Absolute survival and the influence of patient characteristics (sex, disease course (primary progressive (PPMS) vs relapsing onset (R-MS)) and onset age) were estimated by Kaplan-Meier analyses (from birth and disease onset). Mortality relative to the general population was examined using standardised mortality ratios. Excess mortality associated with patient characteristics and time period of cohort entry was assessed by relative survival modelling.

RESULTS

Of 6917 patients, 1025 died. Median survival age was 78.6 years (95% CI 77.5 to 79.7) for women and 74.3 years (95% CI 73.1 to 75.4) for men. Survival from onset was longer for R-MS (49.7 years; 95% CI 47.9 to 51.5) than for PPMS (32.5 years; 95% CI 29.5 to 35.7); however, survival age was similar. The overall standardised mortality ratios was 2.89 (95% CI 2.71 to 3.07), and patients survived approximately 6 years less than expected, relative to the general population. PPMS had a higher relative mortality risk compared with R-MS (relative mortality ratio (RMR) 1.52; 95% CI 1.30 to 1.80). Women with PPMS had a relative survival disadvantage compared with men with PPMS (RMR 1.55; 95% CI 1.19 to 2.01). Relative survival within 10 years of cohort entry was similar between time periods.

CONCLUSIONS

Some of the longest MS survival times are reported here but the risk of death was still greater than in the age, sex and calendar year matched general population. No evidence of increased survival over time was found when improved survival in the general population was taken into consideration.

Coronal imbalance in degenerative lumbar scoliosis: Prevalence and influence on surgical decision-making for spinal osteotomy

AIMS

There is a paucity of information on the pre-operative coronal imbalance in patients with degenerative lumbar scoliosis (DLS) and its influence on surgical outcomes.

PATIENTS AND METHODS

A total of 284 DLS patients were recruited into this study, among whom 69 patients were treated surgically and the remaining 215 patients conservatively Patients were classified based on the coronal balance distance (CBD): Type A, CBD < 3 cm; Type B, CBD > 3 cm and C7 Plumb Line (C7PL) shifted to the concave side of the curve; Type C, CBD > 3 cm and C7PL shifted to the convex side.

RESULTS

A total of 99 of the 284 (34.8%) patient presented with a pre-operative coronal imbalance (mean CBD: 48.5, standard deviation 18.7 mm). More patients with a Type B malalignment were observed than with a Type C malalignment (62 versus 37). A total of 21 pf the 69 (30.4%) surgically treated patients had a post-operative coronal imbalance, which was found to be more prevalent in Type C patients (p < 0.001). At follow-up, less improvement was observed in terms of Short Form-36 Physical Component Score and visual analogue score for back pain (p = 0.034 and 0.025, respectively) in Type C patients.

CONCLUSION

This study shows that patients with Type C coronal malalignment may be at greater risk of post-operative coronal imbalance following posterior osteotomy. Cite this article: Bone Joint J 2016;98-B:1227-33.

Update of PROFEAT: a web server for computing structural and physicochemical features of proteins and peptides from amino acid sequence

Sequence-derived structural and physicochemical features have been extensively used for analyzing and predicting structural, functional, expression and interaction profiles of proteins and peptides. PROFEAT has been developed as a web server for computing commonly used features of proteins and peptides from amino acid sequence. To facilitate more extensive studies of protein and peptides, numerous improvements and updates have been made to PROFEAT. We added new functions for computing descriptors of protein–protein and protein–small molecule interactions, segment descriptors for local properties of protein sequences, topological descriptors for peptide sequences and small molecule structures. We also added new feature groups for proteins and peptides (pseudo-amino acid composition, amphiphilic pseudo-amino acid composition, total amino acid properties and atomic-level topological descriptors) as well as for small molecules (atomic-level topological descriptors). Overall, PROFEAT computes 11 feature groups of descriptors for proteins and peptides, and a feature group of more than 400 descriptors for small molecules plus the derived features for protein–protein and protein–small molecule interactions. Our computational algorithms have been extensively tested and used in a number of published works for predicting proteins of specific structural or functional classes, protein–protein interactions, peptides of specific functions and quantitative structure activity relationships of small molecules. PROFEAT is accessible free of charge at http://bidd.cz3.nus.edu.sg/cgi-bin/prof/protein/profnew.cgi.

Systematic review and meta-analysis comparing three techniques for pancreatic remnant closure following distal pancreatectomy

BACKGROUND

Established closure techniques for the pancreatic remnant after distal pancreatectomy include stapler, suture and anastomotic closure. However, controversy remains regarding the ideal technique; therefore, the aim of this study was to compare closure techniques and risk of postoperative pancreatic fistula (POPF).

METHODS

A systematic review was carried out according to PRISMA guidelines for studies published before January 2014 that compared at least two closure techniques for the pancreatic remnant in distal pancreatectomy. A random-effects model was constructed using weighted odds ratios (ORs).

RESULTS

Thirty-seven eligible studies matched the inclusion criteria and 5252 patients who underwent distal pancreatectomy were included. The primary outcome measure, the POPF rate, ranged 0 from to 70 per cent. Meta-analysis of the 31 studies comparing stapler versus suture closure showed that the stapler technique had a significantly lower rate of POPF, with a combined OR of 0.77 (95 per cent c.i. 0.61 to 0.98; P = 0.031). Anastomotic closure was associated with a significantly lower POPF rate than suture closure (OR 0.55, 0.31 to 0.98; P = 0.042). Combined stapler and suture closure had significantly lower POPF rates than suture closure alone, but no significant difference compared with stapler closure alone.

CONCLUSION

The use of stapler closure or anastomotic closure for the pancreatic remnant after distal pancreatectomy significantly reduces POPF rates compared with suture closure. The combination of stapler and suture closure shows superiority over suture closure alone.

Dynamics of segmental extracellular volumes during changes in body position by bioimpedance analysis

Extracellular volume (ECV) of arms, trunk, and legs determined from segmental bioimpedance data in 11 healthy men (31.6 +/- 7 yr) obtained at the end of a 30-min equilibration phase in the supine body position was compared with ECV determined from whole body measurements (ECVWB). ECV was calculated from extracellular resistance (RECV) identified from the bioimpedance spectrum for a range of 10 frequencies. Whole body RECV (527.6 +/- 55.6 Omega) was equal to the sum of RECV in the arms, trunk, and legs (241.6 +/- 36. 3, 49.2 +/- 5.1, and 236.3 +/- 25.5 Omega, respectively). The sum of equilibrated ECV in arms (1.31 +/- 0.25 liters), trunk (10.08 +/- 1.65 liters), and legs (2.80 +/- 0.82 liters) was smaller than ECVWB (20.90 +/- 2.59 liters). In six subjects who changed from a standing to a supine body position, ECV decreased in arms (-2.59 +/- 2.51%, P = NS) and legs (-10.96 +/- 3.02%, P < 0.05) but increased in the trunk (+4.2 +/- 3.2%, P < 0.05). ECVWB also decreased (-4.98 +/- 1. 41%, P < 0.05). However, the sum of segmental extracellular volumes remained unchanged (-0.06 +/- 0.07%, P = NS). The sum of segmental ECVs is not sensitive to changes in body position, which otherwise interferes with the estimation of ECV in bioimpedance analysis when ECVWB is used.

Direct targeting of SUZ12/ROCK2 by miR-200b/c inhibits cholangiocarcinoma tumourigenesis and metastasis

Background:

The multidrug resistance and distant metastasis of cholangiocarcinoma result in high postoperative recurrence and low long-term survival rates. It has been demonstrated that the ectopic expression of miR-200 suppresses the multidrug resistance and metastasis of cancer. However, the expression and function of miR-200 in cholangiocarcinoma has not yet been described.

Methods:

In this study, we identified dysregulated microRNAs (miRNAs, miR) in cholangiocarcinoma tissue by microarray analysis, and subsequent real-time PCR and northern blot analyses validated the expression of candidate miR. We performed functional analyses and investigated the relationship between miR-200b/c expression and the properties of cholangiocarcinoma cells. A dual luciferase assay was applied to examine the effect of miRNAs on the 3′-UTR of target genes, and we demonstrated the function of the target gene by siRNA transfection identifying the downstream pathway via western blotting.

Results:

We found significantly downregulated expression of four miR-200 family members (miR-200a/b/c/429) and then confirmed that ectopic miR-200b/200c inhibits the migration and invasion of cholangiocarcinoma cells both in vitro and in vivo. We found that miR-200b/c influenced the tumourigenesis of cholangiocarcinoma cells including their tumour-initiating capacity, sphere formation, and drug resistance. We further found that miR-200b/c regulated migration and invasion capacities by directly targeting rho-kinase 2 and regulated tumorigenic properties by directly targeting SUZ12 (a subunit of a polycomb repressor complex).

Conclusion:

Our study shows that miR-200b/c has a critical role in the regulation of the tumorigenic and metastatic capacity of cholangiocarcinoma and reveals the probable underlying mechanisms.

Remodeling of the gut microbiota and structural shifts in Preeclampsia patients in South China

Preeclampsia (PE) is one of the pregnancy metabolic diseases. Since Gut microbiota play important roles in the hosts' metabolism, it is necessary to investigate the gut microbiota in PE patients, so that some intestinal dysbiosis might be detected as a biomarker for PE early diagnosis or as a target for intervention. One hundred subjects were categorized into four groups: 26 PE patients in late pregnancy, healthy individuals in early, middle, and late pregnancy (26/24/24 women). Gut microbiota were analyzed by sequencing the V4 region of the 16S rDNA gene using Illuminal MiSeq. Data were analyzed by multivariate statistics. Bacteroidetes was the dominant bacterium (47.57-52.35%) in the pregnant women in South China. Tenericutes increased while Verrucomicrobia almost disappeared in late pregnancy. In the PE patients, there was an overall increase in pathogenic bacteria, Clostridium perfringens (p = 0.03) and Bulleidia moorei (p = 0.00) but a reduction in probiotic bacteria Coprococcus catus (p = 0.03). Our research suggests that there is a significant structural shift of the gut microbiota in PE patients, which might be associated with the occurrence and development of the disease. However, further studies are required to understand the underlying mechanisms.

Molecular dynamics study of aquaporin-1 water channel in a lipid bilayer

The aquaporin-1 water channel was modeled in a palmitoyl-oleoyl-phosphatidyl-choline lipid bilayer, by means of molecular dynamics simulations. Interaction of the protein with the membrane and inter-monomer interactions were analyzed. Structural features of the channel important for its biological function, including the Asn-Pro-Ala (NPA) motifs, and the diffusion of water molecules into the channels, were investigated. Simulations revealed the formation of single file water inside the channels for certain relative positions of the NPA motifs.

Validation of changes in extracellular volume measured during hemodialysis using a segmental bioimpedance technique

Sum of segmental bioimpedance analysis (BIAs) has recently been introduced as a more accurate estimation of extracellular volume (ECV). The current study was designed to compare the changes in ECV estimated by whole body bioimpedance (BIA(W)) and BIAs and to determine whether BIAs could be used to accurately estimate changes in ECV compared with the ultrafiltration volume (UFV) as measured by the dialysis machine. Ten men (age, 49 +/- 10 years; dry weight, 78 +/- 13 kg) were studied during hemodialysis (HD). A multifrequency bioimpedance analyzer (BIS4000B; Xitron Technologies, San Diego, CA) and a digital switch developed by the authors were used to automatically collect data from three body segments (arm, trunk, and leg) and the whole body using the stated technique. There was a significant difference in delta ECV(W) and UFV at the end of the treatment (2.75 +/- 0.74 L vs 3.95 +/- 0.73 L, p < 0.05) because fluid removal from the trunk has almost no effect on whole body resistance. However, delta ECVs was not significantly different from UFV (3.76 +/- 0.65 L vs 3.95 +/- 0.73 L, p = NS). BIAs is a more accurate approach to monitor changes in ECV during HD than is BIA(W) because changes in local resistance can be allocated to segments with uniform geometry and resistivity. This is a prerequisite for future studies on dynamics of regional fluid distribution during hemodialysis.

Metabolic consequences of body size and body composition in hemodialysis patients

Small body mass index is associated with increased mortality in chronic hemodialysis patients. The reasons for this observation are unclear but may be related to body composition. This study aimed to investigate the body composition in chronic hemodialysis patients. The difference between body mass and the sum of muscle, bone, subcutaneous, and visceral adipose tissue masses, measured by whole body magnetic resonance imaging, was defined as the high metabolic rate compartment representing the visceral mass. Protein catabolic rate was calculated from urea kinetics. Forty chronic hemodialysis patients (mean age 54.7 years; 87.5% African Americans; 45% females) were studied. High metabolic rate compartment expressed in percent of body weight was inversely related to body weight (r=-0.475; P=0.002) and body mass index (r=-0.530; P<0.001). In a multiple linear regression model, protein catabolic rate was significantly correlated only with high metabolic rate compartment (r=0.616; P<0.001). Assuming that protein catabolic rate in addition to protein intake reflects urea and uremic toxin generation, it follows that high metabolic rate compartment is the major compartment involved in their generation. Consequently, uremic toxin production rate may be relatively higher in patients with low body weight and low body mass index as compared to their heavier counterparts. The poorer survival observed in smaller dialysis patients may be related to these relative differences.

Mutations in 3'-long terminal repeat of HERV-W family in chromosome 7 upregulate syncytin-1 expression in urothelial cell carcinoma of the bladder through interacting with c-Myb

Human endogenous retrovirus (HERV) accounts for ∼8% of the human genome. Recent studies have reported that multiple HERV genes and long terminal repeats (LTRs) are involved in human tumorigenesis. Here we demonstrated that HERV-W env (syncytin-1) was overexpressed in 75.6% (62/82) of urothelial cell carcinoma (UCC) tissues of the bladder compared with only 6.1% (5/82) of matched tumor-adjacent tissues (P<0.001). Syncytin-1 overexpression increased proliferation and viability of immortalized human uroepithelial cells. Colony-formation experiments and in-vivo tumor xenografts suggested that syncytin-1 overexpression had oncogenic potential. Syncytin-1 3'-LTR mutations (142T>C and 277A>G) were present in 87.8% (72/82) of UCC tissues. Normal 3'-LTR was found in 12.2% (10/82) of UCC tissues compared with 95.1% (78/82) of matched tumor-adjacent tissues (P<0.001). Interestingly, 3'-LTR mutations were significantly associated with syncytin-1 overexpression. Luciferase assay and expression analysis revealed that 3'-LTR mutations, especially the 142T>C mutation, enhanced the syncytin-1 promoter activity and expression. In-silico analysis, electrophoretic mobility shift assays and chromatin immunoprecipitation assays demonstrated the binding of c-Myb to 3'-LTRs when the mutations occurred. This alternative interaction was found to be dependent on 142T>C mutation. C-Myb activated syncytin-1 promoter activity and expression by binding to mutant 3'-LTRs. Taken together, these data indicate that syncytin-1 overexpression may be an indicator of UCC risk. The 3'-LTR mutations may upregulate syncytin-1 expression, enabling it to participate in UCC tumorigenesis and development by interacting with c-Myb.

Assessment of biocompatibility of 3D printed photopolymers using zebrafish embryo toxicity assays

3D printing has emerged as a rapid and cost-efficient manufacturing technique to enable the fabrication of bespoke, complex prototypes. If the technology is to have a significant impact in biomedical applications, such as drug discovery and molecular diagnostics, the devices produced must be biologically compatible to enable their use with established reference assays and protocols. In this work we demonstrate that we can adapt the Fish Embryo Test (FET) as a new method to quantify the toxicity of 3D printed microfluidic devices. We assessed the biocompatibility of four commercially available 3D printing polymers (VisiJetCrystal EX200, Watershed 11122XC, Fototec SLA 7150 Clear and ABSplus P-430), through the observation of key developmental markers in the developing zebrafish embryos. Results show all of the photopolymers to be highly toxic to the embryos, resulting in fatality, although we do demonstrate that post-printing treatment of Fototec 7150 makes it suitable for zebrafish culture within the FET.

A support vector machines approach for virtual screening of active compounds of single and multiple mechanisms from large libraries at an improved hit-rate and enrichment factor

Support vector machines (SVM) and other machine-learning (ML) methods have been explored as ligand-based virtual screening (VS) tools for facilitating lead discovery. While exhibiting good hit selection performance, in screening large compound libraries, these methods tend to produce lower hit-rate than those of the best performing VS tools, partly because their training-sets contain limited spectrum of inactive compounds. We tested whether the performance of SVM can be improved by using training-sets of diverse inactive compounds. In retrospective database screening of active compounds of single mechanism (HIV protease inhibitors, DHFR inhibitors, dopamine antagonists) and multiple mechanisms (CNS active agents) from large libraries of 2.986 million compounds, the yields, hit-rates, and enrichment factors of our SVM models are 52.4-78.0%, 4.7-73.8%, and 214-10,543, respectively, compared to those of 62-95%, 0.65-35%, and 20-1200 by structure-based VS and 55-81%, 0.2-0.7%, and 110-795 by other ligand-based VS tools in screening libraries of >or=1 million compounds. The hit-rates are comparable and the enrichment factors are substantially better than the best results of other VS tools. 24.3-87.6% of the predicted hits are outside the known hit families. SVM appears to be potentially useful for facilitating lead discovery in VS of large compound libraries.

Multicenter Prospective Trial of Stent Placement in Patients with Symptomatic High-Grade Intracranial Stenosis

BACKGROUND AND PURPOSE

On the basis of the high 1-month stroke and/or death (14.7%) rates associated with stent placement in the Stenting versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis trial, modifications in patient selection and procedural aspects for intracranial stent placement have been recommended. We performed a multicenter prospective single-arm trial to determine whether such modifications would result in lower rates of periprocedural stroke and/or death.

MATERIALS AND METHODS

The study enrolled patients with recent transient ischemic attack or ischemic stroke (excluding perforator ischemic events) related to high-grade (70%-99% in severity) stenosis of a major intracranial artery. Patients were treated by using angioplasty and self-expanding stents 3 weeks after the index ischemic event at 1 of the 10 high-volume centers in China. An independent neurologist ascertained the occurrence of any stroke and/or death within 1 month after the procedure.

RESULTS

A total of 100 consecutive patients were recruited. The target lesions were located in the middle cerebral artery (M1) (n = 38, 38%), intracranial internal carotid artery (n = 17, 17%), intradural vertebral artery (n = 18, 18%), and basilar artery (n = 27, 27%). The technical success rate of stent deployment with residual stenosis of <50% was 100%. The overall 1-month stroke and/or death rate was 2% (95% confidence interval, 0.2%-7.0%). Two ischemic strokes occurred in the pontine region (perforator distribution) in patients following angioplasty and stent placement for basilar artery stenosis.

CONCLUSIONS

The results of this prospective multicenter study demonstrated that modifications in patient selection and procedural aspects can substantially reduce the 1-month stroke and/or death rate following intracranial stent placement.

Segment-specific resistivity improves body fluid volume estimates from bioimpedance spectroscopy in hemodialysis patients

Discrepancies in body fluid estimates between segmental bioimpedance spectroscopy (SBIS) and gold-standard methods may be due to the use of a uniform value of tissue resistivity to compute extracellular fluid volume (ECV) and intracellular fluid volume (ICV). Discrepancies may also arise from the exclusion of fluid volumes of hands, feet, neck, and head from measurements due to electrode positions. The aim of this study was to define the specific resistivity of various body segments and to use those values for computation of ECV and ICV along with a correction for unmeasured fluid volumes. Twenty-nine maintenance hemodialysis patients (16 men) underwent body composition analysis including whole body MRI, whole body potassium (40K) content, deuterium, and sodium bromide dilution, and segmental and wrist-to-ankle bioimpedance spectroscopy, all performed on the same day before a hemodialysis. Segment-specific resistivity was determined from segmental fat-free mass (FFM; by MRI), hydration status of FFM (by deuterium and sodium bromide), tissue resistance (by SBIS), and segment length. Segmental FFM was higher and extracellular hydration of FFM was lower in men compared with women. Segment-specific resistivity values for arm, trunk, and leg all differed from the uniform resistivity used in traditional SBIS algorithms. Estimates for whole body ECV, ICV, and total body water from SBIS using segmental instead of uniform resistivity values and after adjustment for unmeasured fluid volumes of the body did not differ significantly from gold-standard measures. The uniform tissue resistivity values used in traditional SBIS algorithms result in underestimation of ECV, ICV, and total body water. Use of segmental resistivity values combined with adjustment for body volumes that are neglected by traditional SBIS technique significantly improves estimations of body fluid volume in hemodialysis patients.

Sum of segmental bioimpedance analysis during ultrafiltration and hemodialysis reduces sensitivity to changes in body position

BACKGROUND

Bioimpedance, a noninvasive technique to analyze body composition, has attracted interest in determining body hydration in hemodialysis patients. However, the so-called whole-body (wrist-to-ankle) bioimpedance analysis (WBIA) is sensitive to changes in regional fluid distribution and tends to underestimate fluid changes during ultrafiltration in hemodialysis patients. The aim of this study was to show that volume changes calculated from a new approach, that is, segmental bioimpedance analysis (SBIA), are not affected by changes in body position.

METHODS

Ten male patients (age 44 +/- 8 years, target weight 70.8 +/- 10 kg) were studied during their regular hemodialysis treatment while maintaining either a sitting or a supine body position throughout the study. Extracellular volume was calculated from extracellular resistance obtained from bioimpedance data measured for a range of frequencies (5 to 500 kHz) using the Xitron BIS4000B analyzer. Wrist-to-ankle measurements were compared with segmental arm, trunk, and leg measurements.

RESULTS

Changes in extracellular volume estimated from wrist-to-ankle measurements only reached 80 +/- 13% and 65 +/- 17% of the actual change in body mass during sitting and supine dialysis treatments, respectively. However, when segmental measurements were analyzed, the calculated change in extracellular volume was 101 +/- 6% and 100 +/- 3% of the actual change in body mass during the sitting and supine treatments, respectively.

CONCLUSIONS

SBIA properly identifies regional fluid changes and provides an appropriate measure of fluid changes caused by ultrafiltration and hemodialysis. The volume estimation based on the sum of segmental bioimpedance measurements is independent of body position, which is a prerequisite for applications in everyday practice.

Ribozyme-mediated high resistance against potato spindle tuber viroid in transgenic potatoes

A hammerhead ribozyme [R(-)] targeting the minus strand RNA of potato spindle tuber viroid (PSTVd) and a mutated nonfunctional ribozyme [mR(-)] were designed, cloned, and transcribed. As predicted, both monomer and dimer transcripts of the active R(-) ribozyme gene could cleave the PSTVd minus strand dimer RNA into three fragments of 77, 338, and 359 bases in vitro at 25 and 50 degrees C. The tandem dimer genes of R(-) and mR(-) were subcloned separately into the plant expression vector pROK2. Transgenic potato plants (cultivar Desirée) were generated by Agrobacterium tumefaciens-mediated transformation. Twenty-three of 34 independent transgenic plant lines expressing the active ribozyme R(-) resulted in having high levels of resistance to PSTVd, being free of PSTVd accumulation after challenge inoculation with PSTVd, but the remaining lines showed weaker levels of resistance to PSTVd with low levels of PSTVd accumulation. In contrast, 59 of 60 independent transgenic lines expressing the mutated ribozyme mR(-) were susceptible to PSTVd inoculation and had levels of PSTVd accumulation similar to that of the control plants transformed with the empty vector. The resistance against PSTVd replication was stably inherited to the vegetative progenies.

Experimental studies of the material properties of the forewing of cicada(Homóptera, Cicàdidae)

Detailed investigations on the structural and mechanical properties of the forewing of the cicada were carried out. Measurement of the structures of the wings showed that the thickness of the membrane of each cell and the diameter of each vein were non-uniform in both the longitudinal and transverse directions, and their means were approximately 12.2 and 133.3 μm,respectively. However, the aspect ratios of the wings and the bodies were quite uniform and were approximately equal to 2.98 and 2.13, respectively. Based on the measured thickness, mass and area of the membranes of the cells,the mean density and the mean area density of the wing were approximately 2.3 g cm-3 and 2.8×10-3 g cm-2,respectively. In addition, the diameters of the veins of the wings, including the diameters of the holes in the vein of the leading edge, were examined. The mechanical properties of the wing were investigated separately by nanoindentation and tensile testing. The results indicated that the mean Young's modulus, hardness and yield stress of the membranes of the wings were approximately 3.7 GPa, 0.2 GPa and 29 MPa, respectively, and the mean Young's modulus and strength of the veins along the direction of the venation of wings were approximately 1.9 GPa and 52 MPa, respectively. Finally, the relevant results were briefly analyzed and discussed, providing a guideline to the biomimetic design of the aerofoil materials of micro air vehicles.