Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy.

Cell mechanical behaviour is increasingly recognised as a central biophysical parameter in cancer and stem cell research, and methods of investigating their mechanical behaviour are therefore needed. We have developed a novel qualitative method based on quantitative phase imaging which is capable of investigating cell mechanical behaviour in real-time at cellular resolution using optical coherence phase microscopy (OCPM), and stimulating the cells non-invasively using hydrostatic pressure. The method was exemplified to distinguish between cells with distinct mechanical properties, and transient change induced by Cytochalasin D. We showed the potential of quantitative phase imaging to detect nanoscale intracellular displacement induced by varying hydrostatic pressure in microfluidic channels, reflecting cell mechanical behaviour. Further physical modelling is required to yield quantitative mechanical properties.

Validation of post-traumatic stress disorder (PTSD) and complex PTSD using the International Trauma Questionnaire.

OBJECTIVE: The 11th version of the International Classification of Diseases (ICD-11) has proposed two related trauma diagnoses: Post-traumatic stress disorder (PTSD) and Complex PTSD (CPTSD). Using a newly developed, disorder-specific measure of PTSD and CPTSD called the International Trauma Questionnaire (ITQ) the current study will (i) assess the factorial validity of ICD-11 PTSD and CPTSD; (ii) provide the first test of the discriminant validity of these constructs; and (iii) provide the first comparison of ICD-11, and Diagnostic and Statistical Manual, Fifth Edition (DSM-5), PTSD diagnostic rates using disorder-specific measures. METHOD: ICD-11 and DSM-5 PTSD-specific measures were completed by a British clinical sample of trauma-exposed patients (N = 171). The structure and validity of ICD-11 PTSD and CPTSD were assessed by means of factor analysis and assessing relationships with criterion variables. RESULTS: Diagnostic rates under ICD-11 were significantly lower than those under DSM-5. A two-factor second-order model reflecting the distinction between PTSD and CPTSD best represented the data from the ITQ; and the PTSD and CPTSD factors differentially predicted multiple psychological variables. CONCLUSION: The factorial and discriminant validity of ICD-11 PTSD and CPTSD was supported, and ICD-11 produces fewer diagnostic cases than DSM-5.

Non linear optical microscopy of adipose-derived stem cells induced towards osteoblasts and adipocytes.

Adipose-derived stem cells (ADSCs) are adult stem cells isolated from lipoaspirates. They are a good candidate for autologuous cell therapy and tissue engineering. For these applications, label-free imaging could be critical to assess noninvasively the efficiency of stem cell (SC) differentiation. We report on the development and application of a multimodal microscope to monitor and quantify ADSC differentiation into osteoblasts and adipocytes.

A framework for the concurrent consideration of occupational hazards and obesity.

Occupational hazards and obesity can lead to extensive morbidity and mortality and put great financial burden on society. Historically, occupational hazards and obesity have been addressed as separate unrelated issues, but both are public health problems and there may be public health benefits from considering them together. This paper provides a framework for the concurrent consideration of occupational hazards and obesity. The framework consists of the following elements: (i) investigate the relationship between occupational hazards and obesity, (ii) explore the impact of occupational morbidity and mortality and obesity on workplace absence, disability, productivity and healthcare costs, (iii) assess the utility of the workplace as a venue for obesity prevention programs, (iv) promote a comprehensive approach to worker health and (v) identify and address the ethical, legal and social issues. Utilizing this framework may advance the efforts to address the major societal health problems of occupational hazards and obesity.

Fabrication of conjugated polymers nanostructures via direct near-field optical lithography.

We report our investigations into the fabrication of nanostructures of poly(p-phenylene vinylene) via direct scanning near-field lithography of its soluble precursor. Our technique is based on the spatially selective inhibition of the precursor solubility by exposure to the ultraviolet optical field present at the apex of commercially available, Au-coated near-field probes with aperture diameters between 40 and 80 nm (+/-5 nm). After development in methanol and thermal conversion under vacuum we obtain features with a minimum dimension of 160 nm. We analyse our results via tapping-mode atomic force microscopy, and find a clear phase contrast between the core and the centre of the lithographed features, corroborating the hypothesis that hard, fully insolubilised regions are surrounded by a gel-like phase, which we estimate of the order of 110-130 nm for the smallest features, by comparing our experiments with simulations carried out using a Bethe-Bouwkamp model. Use of such model also allows us to discuss the influence of probe size, tip-sample distance, and film thickness on the resolution of the lithographic process. We demonstrate the use of the technique for the direct writing of two-dimensional periodic structures with intentional defects and a periodicity relevant to applications in the visible range.

Prevalence and distribution of petechiae in well babies.

AIMS: To determine the prevalence of petechial spots in well babies. METHODS: A total of 116 babies under the age of 12 months were fully examined at child health surveillance clinics. The number and site of petechiae were recorded together with details of possible causes. RESULTS: A total of 27.6% of babies had one or more petechiae, 8.6% had two or more petechiae, and 2.6% had more than two. None of these babies subsequently developed sepsis. CONCLUSIONS: Many well infants examined in the community are likely to have petechial spots. In this setting one or two petechiae are common and their presence should not be taken as pathological without other clinical signs. Recognition of this fact may also be helpful when examining otherwise well infants with petechiae in a secondary care setting.

Stimulation of synaptosomal D-[(3)H]aspartate transport by substance P in rat brain.

The effect of the neuropeptide, substance P, on the transport of D-[(3)H]aspartate into rat striatal synaptosomes was studied. Almost 90% of the total transport of D-[(3)H]aspartate was sodium-dependent and the maximum rate (V(max)) of this transport was increased by 34% of control by 2.5 nM substance P (EC(50)=0.52 nM). In contrast, sodium-independent transport was inhibited by substance P. The NK(1) antagonist, L706303 (500 nM) blocked the stimulation of D-[(3)H]aspartate transport by 2.5 nM substance P, but did not alter D-aspartate uptake in the absence of substance P. These results indicate that high affinity glutamate transporters in the brain may be under positive regulation by substance P, and suggest a previously-unidentified mechanism of control of glutamate transport.

Vertical and horizontal fluxes of plutonium and americium in the western Mediterranean and the Strait of Gibraltar.

New data on the vertical distributions of plutonium and americium in the waters of the western Mediterranean and the Strait of Gibraltar are examined in terms of the processes governing their delivery to, transport in and removal from the water column within the basin. Residence times for plutonium and americium in surface waters of approximately 15 and approximately 3 years, respectively, are deduced, and it is shown that by the mid 1990s only approximately 35% of the 239,240Pu and approximately 5% of the 241Am deposited as weapons fallout still resided in the water column. Present 239,240Pu inventories in the water column and the underlying sediments are estimated to be approximately 25 TBq and approximately 40 TBq, respectively, which reconcile well with the time-integrated fallout deposition in this zone, taken to be approximately 69 TBq. The data show that there are significant net outward fluxes of plutonium and americium from the basin through the Strait of Gibraltar at the present time. These appear to be compensated by net inward fluxes of similar magnitude through the Strait of Sicily. Thus, the time-integrated fallout deposition in the western basin can be accounted for satisfactorily in terms of present water column and sediment inventories. Enhanced scavenging on the continental shelves, as evidenced by the appreciably higher transuranic concentrations in shelf sediments, supports this contention.

High-performance liquid chromatographic method for sensitive determination of the alkylating agent CB1954 in human plasma.

A high-performance liquid chromatography (HPLC) method is described for the measurement of the weak alkylating agent CB1954 in human plasma. CB1954 can be used as an innocuous prodrug designed for activation by bacterial nitroreductases in strategies of gene-directed enzyme-prodrug therapy, and becomes activated to a potent bifunctional alkylating agent. The HPLC method involves precipitation and solvent extraction and uses Mitomycin C (MMC) as an internal standard, with a retention time for MMC of 5.85 +/- 0.015 min, and for CB1954 of 10.72 +/- 0.063 min. The limit of detection for CB1954 is 2.9 ng/ml, and this compares favourably with systems involving direct analysis of plasma (limit of detection 600 ng/ml, approximately). The method is now being used for pharmacokinetic measurements in plasma samples from cancer patients entering phase I clinical trials of CB1954. Results using serial plasma samples from one patient are presented. The patient was treated intravenously with CB1954 (6 mg/m2), and plasma clearance of the drug showed biphasic kinetics with alpha half-life 14.6 min, and beta half-life 170.5 min.

An evaluation of Vitek--an automated system for bacterial identification and susceptibility testing.

We evaluated the Vitek system for bacterial identification and susceptibility testing with reference to its speed, staffing requirements, user friendliness, and data management. Its performance was satisfactory in all these dimensions, but it is expensive.

Intimal sarcoma of the superior vena cava.

A case of superior vena cava syndrome caused by a primary intimal sarcoma of the superior vena cava is described. The known causes of superior vena caval obstruction are discussed, together with the difficulties in identifying the underlying lesion. The possibility of a primary superior vena caval neoplasm as a cause of superior vena caval obstruction should be considered in patients presenting with superior vena caval syndrome.

Effects of hydralazine and increased cardiac output on recombinant tissue plasminogen activator-induced thrombolysis in canine pulmonary embolism.

We employed a canine model of pulmonary embolism, induced by injection of autologous radiolabelled blood clots, to investigate effects of hydralazine and an increase in cardiac output per se on recombinant tissue plasminogen activator-induced thrombolysis. Emboli increased pulmonary artery pressure (PAP) and decreased CO from 2.7 to 1.8 L/min-1. Following embolization, dogs were randomly divided into three groups. Group 1 received .5 mg/kg of rtPA over 30 minutes. Group 2 received the same dose of rtPA and were pretreated with hydralazine to increase CO approximately 50 percent. In the group 3 dogs, CO was increased by opening a systemic A-V fistula. Following embolization, CO remained low in group 1, the mean 2 h time-averaged CO was 1.9 L/min-1. The CO was 2.9 and 3.1 L/min-1 in groups 2 and 3, respectively. Corresponding to the increased flow in groups 2 and 3, rate and extent of pulmonary thrombolysis significantly increased. These results indicate that an increase in CO augments rtPA-induced pulmonary thrombolysis.

Base-pair substitutions alter the site-specific mutagenicity of UV and MNNG in the SUP4-o gene of yeast.

Yeast strains carrying SUP4-o genes that have base-pair substitutions at hotspots for UV or MNNG mutagenesis were treated with these agents. In both cases, the induced mutation frequencies were substantially reduced. Furthermore, specific substitutions at positions in SUP4-o that had not been mutated by MNNG resulted in the recovery of MNNG-induced mutations at these sites. These results demonstrate that base-pair identity is an important factor determining the site-specific mutagenicity of UV and MNNG in yeast. For UV, our findings suggest that the type of lesion that is induced, but not flanking DNA sequences, plays a role in specifying mutability at the sites examined. In contrast, DNA sequence context seems to be an important factor for MNNG mutagenesis.

Migration and keratinization of cells in wool follicles.

Migration of cells in wool follicles of an adult Merino sheep was studied autoradiographically in skin samples taken at intervals after an intravenous injection of [3H]thymidine. Fibre and inner root sheath cells incorporated [3H]thymidine in a cone-shape region of the follicle bulb. Labelled inner sheath cells migrated out of the bulb ahead of contemporaneous cells in the fibre and remained in advance, although to a progressively lesser extent, until the inner sheath cells sloughed into the follicle lumen. Outer root sheath cells incorporated [3H]thymidine along the length of the follicle. Cells in the proximal half of the outer sheath migrated inwards and distally and sloughed into the follicle lumen before contemporaneous inner sheath cells. Other cells in the distal half of the outer sheath migrated past the level where cells from the proximal population were shed and also sloughed into the lumen. In the most distal part of the outer sheath, which formed the epidermis-like lining of the follicle canal, little migration of cells was observed during 8 days of observation. The specific activity of tritium in fibres plucked from the same sheep at intervals after the intravenous injection of [3H]thymidine was determined by scintillation counting and assessed in terms of cell migration and hardening of the fibres. The time which the specific activity of solvent-degreased fibres reached a maximum was found to give an estimate of the time for cells in the fibre to migrate to the upper limit of the keratogenous zone. When the plucked fibres were extracted with 8 M urea the times of the maximum specific activities of the urea-dispersible and urea-insoluble material provided respectively estimates of the times at which hardening of the fibres began and ended. The effects of different planes of nutrition were examined in two other Merino sheep by radioassay of fibres plucked after intravenous injections of [3H]thymidine given after equilibration period of at least 2 months on each level of feeding. A high plane of nutrition the rate of cell migration and hastened the onset of hardening of the fibres, but prolonged the hardening process. The prolongation of the hardening process was confirmed by the specific activities of fibres plucked after intravenous injections of [35S]cystine.