Model predictive glycaemic regulation in critical illness using insulin and nutrition input: a pilot study

Stress-induced hyperglycaemia is prevalent in intensive care, impairing the immune response. Nutritional support regimes with high glucose content further exacerbate the problem. Tight glucose control has been shown to reduce mortality by up to 43% if levels are kept below 6.1 mmol/L. This research develops a control algorithm with insulin and nutritional inputs for targeted glucose control in the critically ill. Ethics approval for this research was granted by the Canterbury Ethics Committee. Proof-of-concept clinical pilot trials were conducted on intubated, insulin-dependent Christchurch ICU patients (n=7) on constant nutritional support. A target 10-15% reduction in glucose level per hour for a desired glucose level of 4-6 mmol/L was set. 43% and 91% of glucose targets were achieved within +/-5 and +/-20%, respectively. The mean error was 8.9% (0.5 mmol/L), with an absolute range [0, 2.9] mmol/L. End glucose levels were 40% lower compared to initial values. All large target errors are attributable to sudden changes in patient physiology at low glucose values, rather than systemic deficiencies. Target errors are consistent with and explainable by published sensor error distributions. The results show that intensive model-based glucose management with nutrition control reduced absolute glucose levels progressively while reducing the severity of glycaemic fluctuation even with significant inter-patient variability and time-varying physiological condition. Trials spanning longer periods of time are in development to verify the short-term pilot studies performed and to test the adaptability of the controller. Clinically, these results indicate potential in clinical use to reduce ICU mortality as well as reduce risk of severe complications.

Collinear superposition of multiple helical beams generated by a single azimuthally modulated phase-only element

We propose a highly efficient approach to generating multihelix beams that contain more than one helical mode, and the power distribution over helical modes is adjustable. A multihelix beam embedded with three collinear helical modes is demonstrated by use of a spatial light modulator.

Tear function and goblet cell density after pterygium excision

PURPOSE

To evaluate the short-term effect of pterygium excision on tear function and conjunctival goblet cell density.

METHODS

In all, 70 patients (70 eyes) with primary pterygia who underwent a bare-sclera procedure were enrolled in this study. Tear break-up time, Schirmer, and tear-ferning tests and conjunctival goblet cell density obtained by impression cytology were evaluated before and 1 month after surgery.

RESULTS

At 1 month postoperation, the tear break-up time (11.49+/-3.76 s) was significantly prolonged when compared with the preoperation tear break-up time (9.74+/-3.43 s, P=0.002). Before surgery, only 17% of the patients showed normal crystallization in the tear-ferning test. This proportion was significantly increased to 90% 1 month after surgery (P<0.001). There is no significant difference in the Schirmer test value between pre- and postsurgery (P>0.05). The mean goblet cell density in conjunctival impression specimens before surgery was 41.82+/-18.29/10 fields, which was increased significantly 1 month after surgery (P<0.001) with a mean cell density of 50.67+/-18.71/10 fields.

CONCLUSION

Tear function in patients with primary pterygium improves after pterygium excision, which indicates that pterygium has a close relationship with dry eye.

Cytotoxicity and apoptosis induction of some selected marine bacteria metabolites

AIMS

To study the potential apoptosis effects of cytotoxic marine bacterial metabolites on human HeLa cell line.

METHODS AND RESULTS

After HeLa cells were routinely cultured, tetrazolium-based colorimetric assay for cytotoxicity was performed to screen the marine bacteria extracts showing 12 strains active. To find the potential active strain with apoptosis mechanism, a battery of apoptosis assays, including AO/EB staining, TUNEL assay (terminal-deoxynucleotidyl transferase mediated nick end labelling), gel electrophoresis and flow cytometry, were used to determine whether apoptosis was involved in HeLa cell cytotoxicity of marine bacterial extracts. The results indicated that four strains could induce cell shrinkage, cell membrane blebbing, formation of apoptotic body and DNA fragmentation.

CONCLUSIONS

Crude extracts of 12 of 153 strains of marine bacteria showed cytotoxic effects with ID50 ranged from 77.20 to 199.84 microg ml(-1), in which eight strains of bacteria were associated bacteria. The metabolites in the strains of QD1-2, NJ6-3-1, NJ1-1-1 and SS6-4 were able to induce HeLa cells apoptosis. Furthermore, the assessment by flow cytometry indicated that the hypodiploid apoptotic cells increased in a time-dependent manner, suggesting that induced apoptosis occurred from 24 h to 48 h after the extracts treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results suggested that the compounds from fermentation in these four marine bacterial strains could be candidates for developing apoptosis specific anti-tumour agents with lower toxicity. This study indicated that associated marine bacteria could be good source to find cytotoxic metabolites, and some cytotoxic marine bacterial metabolites could have apoptosis mechanisms.

Endothelial survival factors and spatial completion, but not pericyte coverage of retinal capillaries determine vessel plasticity

Pericyte loss and capillary regression are characteristic for incipient diabetic retinopathy. Pericyte recruitment is involved in vessel maturation, and ligand-receptor systems contributing to pericyte recruitment are survival factors for endothelial cells in pericyte-free in vitro systems. We studied pericyte recruitment in relation to the susceptibility toward hyperoxia-induced vascular remodeling using the pericyte reporter X-LacZ mouse and the mouse model of retinopathy of prematurity (ROP). Pericytes were found in close proximity to vessels, both during formation of the superficial and the deep capillary layers. When exposure of mice to the ROP was delayed by 24 h, i.e., after the deep retinal layer had formed [at postnatal (p) day 8], preretinal neovascularizations were substantially diminished at p18. Mice with a delayed ROP exposure had 50% reduced avascular zones. Formation of the deep capillary layers at p8 was associated with a combined up-regulation of angiopoietin-1 and PDGF-B, while VEGF was almost unchanged during the transition from a susceptible to a resistant capillary network. Inhibition of Tie-2 function either by soluble Tie-2 or by a sulindac analog, an inhibitor of Tie-2 phosphorylation, resensitized retinal vessels to neovascularizations due to a reduction of the deep capillary network. Inhibition of Tie-2 function had no effect on pericyte recruitment. Our data indicate that the final maturation of the retinal vasculature and its resistance to regressive signals such as hyperoxia depend on the completion of the multilayer structure, in particular the deep capillary layers, and are independent of the coverage by pericytes.

Fractional optical vortex beam induced rotation of particles

We experimentally demonstrate optical rotation and manipulation of microscopic particles by use of optical vortex beams with fractional topological charges, namely fractional optical vortex beams, which are coupled in an optical tweezers system. Like the vortex beams with integer topological charges, the fractional optical vortex beams are also capable of rotating particles induced by the transfer of orbital angular momentum. However, the unique radial opening (low-intensity gap) in the intensity ring encompassing the dark core, due to the fractional nature of the beam, hinders the rotation significantly. The fractional vortex beam's orbital angular momentum and radial opening are exploited to guide and transport microscopic particles.

[Isolation and expression profiling of the Pto-like gene SsPto from Solanum surattense]

A novel Pto-like gene (designated as SsPto) is cloned from yellow-fruit nightshade (Solanum surattense). The full-length cDNA of SsPto is 1331 bp long with an open reading frame of 960 bp encoding a polypeptide of 320 amino acid residues. The deduced SsPto protein has a calculated molecular weight of 36.21 kDa with an isoelectric point of 6.18. Multiple sequence alignment shows that SsPto protein shares 71.4% and 71.6% identities to Pto proteins from Lycopersicon pimpinellifolium and L. hirsutum respectively. Genomic Southern blot analysis indicates the presence of a small family of SsPto in the S. surattense genome. SsPto is found to be constitutively expressed in the S. surattense plant with the highest expression in stems. However, under induction by TMV for 6 days, SsPto expresses the highest in roots. Further expression analysis reveals that the signaling components of defense/stress pathways, such as methyl jasmonate (MeJA), salicylic acid (SA), gibberellic acid (GA3) and hydrogen peroxide (H2O2), up-regulate the SsPto transcript levels over the control. Cold treatment, nevertheless, has no significant effect on SsPto expression whereas SsPto expression is down-regulated by dark treatment. Our findings suggest that this novel stress- and pathogen-inducible SsPto from S. surattense may participate not only in the defense/stress responsive pathways, but also in diverse processes of plant's growth and development.

Comparison of subcooled liquid vapor pressures of polychlorinated dibenzo-p-dioxins and dibenzofurans predicted by QSPR and GC-RI methods

Subcooled liquid vapor pressures (P(L)) are of great importance for assessing the persistent behavior of organic pollutants. As P(L) cannot be determined by direct experiments, it is of interest to develop and evaluate various predictive methods. In the current study, gas chromatography retention index (GC-RI) and quantitative structure-property relationship (QSPR) methods were used to develop predictive models for P(L) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The model development was based on P(L) values converted from consistent experimental solid vapor pressures (P(S)). The P(L) values predicted by the two methods are highly consistent with each other, and in-between sets of values predicted by others. Since the QSPR method can be regarded as independent of experiments, and can be used to interpret intermolecular interactions that govern the magnitude of P(L), it may be superior to the GC-RI method.

Combining laparoscopic and endovascular techniques to improve the outcome of aortic endografts. Hybrid techniques

Aortic endografting can be performed with a high initial success rate yet with the need for lifelong surveillance because of numerous long term problems. Among these graft migration, typ II endoleaks and endotension require treatment to prevent abdominal aortic aneurysm (AAA) rupture. We describe our experience with laparoscopic clipping of lumbar arteries and the inferior mesenteric artery (IMA) to prevent Type II leaks as well as with different banding procedures. Several ways to perform active graft fixation are described. Since we believe that active downsizing of the aneurysm reduces some of the intermediate term problems we go a step further and evacuate the thrombus to downsize the aneurysm to prevent longitudinal shrinkage. Laparoscopic techniques can also be used to obtain direct vascular access. This permits insertion of a thoracic endograft directly into the aorta in patients with diseased iliac vessels. Endovascular aneurysm repair (EVAR) insertion under laparoscopic navigation without contrast dye in cases with renal insufficiency is described. We describe our technique of total laparoscopic conversion after failed endografting. Future perspectives and preliminary experience with an aortic stapler are discussed.

Information theory in prediction of cleavage sites of signal peptides

Information theory is used to analyze the character of signal peptide quantitatively, especially residents. On the basis of the above analysis, a method named simplified information-matrix has been developed to predict the cleavage sites of signal peptides. A comparison between the results of weight-matrix and simplified information-matrix is presented.

From Al4B2O9 Nanowires to BN-Coated Al18B4O33 Nanowires

A novel route was proposed to completely coat aluminum borate nanowires by in situ providing the precursor for BN coating. Uniformly BN-coated Al18B4O33 nanowires could be obtained by the reaction of Al4B2O9 nanowires with ammonia at high temperature. The high-temperature unstable Al4B2O9 nanowires were converted into Al18B4O33 nanowires, simultaneously evaporated boron oxide. The reaction between the in situ generated vapors and ammonia ensures that the BN layers are attached tightly on the surface of the as-formed Al18B4O33 nanowires.

Metal oxide coating on carbon nanotubes by a methanol-thermal method

A methanol-thermal method has been developed to fabricate one-dimensional composite nanowires by coating multiwalled carbon nanotubes with lanthanum oxide and iron oxide, respectively. The coating structure and composition have been investigated by transmission electron microscopy and the X-ray energy dispersive spectrum. Magnetic measurement for the iron oxide coatings indicated that the coercivity has been enhanced after coating. The method reported here provides a novel procedure for the fabrication of one-dimensional composite nanostructures.

Deterministic approach to the generation of modified helical beams for optical manipulation

We present a deterministic method to generate modified helical beams which create optical vortices with desired dark core intensity patterns in the far-field. The experiments are implemented and verified by a spatial light modulator (SLM), which imprints a phase function onto the incident wavefront of a TEM00 laser mode to transform the incident beam into a modified helical beam. The phase function can be calculated once a specific dark core shape of an optical vortex is required. The modified helical beam is exploited in optical manipulation with verification of its orbital angular momentum experimentally.

Characterization of a novel HLA-DQB1 allele, DQB1*020102

A novel human leukocyte antigen (HLA)-DQB1 allele, DQB1*020102, was detected in a 28-year-old woman of Han ethnic in Guangzhou, China. Compared with HLA-DQB1*020101 and HLA-DQB1*0202, they differed in only one nucleotide at the position 167 (C to T) of exon 2, which was a highly conserved position. This is a synonymous mutation, which does not cause any change in the amino acid sequence of mature protein.

Isolation and molecular characterization of fluoroquinolone-resistant Escherichia coli from poultry litter

Nineteen fluoroquinolone-resistant Escherichia coli strains were isolated from poultry litter. Sixteen of the 19 strains were serotyped to groups 6, 8, 53, 56, 153, and 174. Three strains were not serotyped to any known group. All isolates were resistant to multiple antibiotics. Most strains were resistant to gentamicin, kanamycin, chloramphenicol, and streptomycin. Ribotyping of the multidrug-resistant isolates with restriction enzyme PvuII showed 5 different ribogroups, suggesting independent development of resistance instead of clonal spread. Quinolone resistance was associated with mutations of the quinolone resistance-determining region (QRDR) of the gyr A gene in all cases. To determine the incidence of gyr A mutations in fluoroquinolone-resistant E. coli isolates, a rapid PCR-based assay was used by amplifying a 164-bp region of the gyr A gene containing the mutation sites followed by digestion of the PCR product with restriction enzyme HinfI. A higher level of resistance to ciprofloxacin [minimum inhibitory concentration (MIC) >4 microg] was associated with double mutations, but the mutants with a low level of resistance (MIC <2 microg) had only a single mutation. Those strains that were ciprofloxacin-resistant (MIC <2 microg) had a single mutation of a C-to-T transition at position 248 (Ser 83-->Leu) or a G-to-A transition at position 259 (Asp 87-->Asn). The ciprofloxacin-resistant (MIC >4 microg) isolates had mutations at both positions. Fluoroquinolone resistance was present among different serotypes and ribotypes, and drug resistance profiles suggest that the incidence of resistance does not indicate a clonal population in avian E. coli.

A novel HLA-DRB1*09 allele, HLA-DRB1*090103*, isolated from the Han population of Guangdong, China

A novel HLA-DRB1*09 allele, HLA-DRB1*090103, has been identified in a Guangdong Han person. Its sequence was confirmed by sequencing polymerase chain reaction products and clones. This allele differed by one nucleotide from HLA-DRB1*090102 at position 50(G-->C), which represents a silent mutation.

Evaluation of adipocyte apoptosis by laser scanning cytometry

OBJECTIVE

Adipocyte apoptosis plays an important role in adipose tissue homeostasis and can be altered under a variety of physiological and pathological conditions. This study was carried out to determine whether laser scanning cytometry (LSC) can be used to measure changes in apoptosis of adipocytes over time.

DESIGN

LSC was used to investigate adipocyte apoptosis induced by tumor necrosis factor-alpha (TNF-alpha), a cytokine that is associated with obesity and insulin resistance. LSC, a slide-based solid phase cytofluorometer, provides quantitative flow fluorescence data together with morphological information for apoptotic detection. Both 3T3-L1 cells and rat adipocytes from primary cell culture were incubated with 0 or 25 nM TNF-alpha for up to 24 h. Both the FITC-conjugated annexin V/propidium iodide assay and the TUNEL assay were used to distinguish cells with apoptotic characteristics from nonapoptotic cells.

RESULTS

Apoptosis did not increase over time in the absence of TNF-alpha for both 3T3-L1 cells and rat primary adipocytes. For both 3T3-L1 cells and rat primary adipocytes, a significant increase in the percentage of apoptotic cells was observed by 3-4 h incubation with TNF-alpha (P<0.05). By 24 h, more than 50% of cells incubated with TNF-alpha were apoptotic (P<0.001). This process was also associated with morphological changes typical of adipocytes undergoing apoptosis. By estimating the percentage of cell subpopulations after different times of incubation with TNF-alpha, we were able to develop grading parameters, based on the adipose apoptotic measurements.

CONCLUSION

With morphological information, LSC can be a useful tool to evaluate adipocyte apoptosis.