Significance of DNA ploidy in the treatment of T1 glottic carcinoma

OBJECTIVE: To assess the role of DNA ploidy as a predictor of radioresistance in T1 glottic carcinoma. DESIGN: Case-control study. Flow cytometric DNA ploidy measurements were performed on formalin-fixed paraffin-embedded tumor specimens from 15 patients with T1 glottic laryngeal carcinomas in whom radiotherapy had failed and from a matched group of 15 patients in whom an identical radiotherapy regimen was curative. Analysis of DNA content was performed blind to outcome of treatment. SETTING: Academic tertiary referral medical center. PARTICIPANTS: Thirty patients with clinically staged T1, N0, M0 glottic carcinoma. INTERVENTION: All patients received radiation to the larynx through opposed lateral ports at a total dose of 64 to 70 Gy. RESULTS: Ten diploid and five aneuploid histograms were found in the resistant group, and six diploid and nine aneuploid histograms were found in the radiosensitive group. This difference was not statistically significant. A trend toward a higher relapse rate after radiotherapy (62.5%) among patients with diploid tumor compared with those with aneuploid tumor (35.7%) was noted. CONCLUSIONS: DNA ploidy did not predict response to radiotherapy in patients with T1 glottic cancer, probably because of the small number of patients. A trend toward lower risk of local recurrence after radiotherapy in aneuploid tumors was noted. A larger prospective study is needed to assess the value of DNA ploidy in the treatment of early laryngeal cancer.     

Particulate carbon and other components of soot and carbon black

Soot is an unwanted by-product of combustion or pyrolysis of organic compounds. At least four morphologically distinct forms of particulate carbon can be recognized in various types of soot:

1. (1) aciniform carbon (AC), composed of spheroidal carbon particles fused together in aggregates of colloidal dimensions

2. (2) carbonaceous microgel (CM), in which spheroidal carbon particles are embedded in carbon or carbonaceous material

3. (3) carbon cenospheres

4. (4) coke and char fragments.

We have examined 18 soots from various sources. Domestic chimney soots have very little AC but consist mainly of char fragments, CM, ash, and soluble organic fraction (SOF); whereas diesel soots consist mainly of AC and SOF. Carbon black is a manufactured product consisting almost entirely of AC. Carbon blacks can be distinguished from many soots by their morphology, and from all soots investigated in the present study by their purity. Thus, carbon blacks have less than 0.3% SOF removable by toluene, and less than 1% ash, whereas soots exceed at least one of these limits by several fold. Because of differences in origin, function, and composition, common nomenclature carbon black with soot is inappropriate.

Authoritarianism, leader acceptance, and group cohesion.

An examination of the validity of the Frommian compromise between leader-centered and member-centered theories of group cohesiveness is made, using a sample of enlisted men of the Air Defense Command. The variables of authoritarianism and leader-acceptance were measured in this sample by means of Likert-type scales. The Frommian hypothesis is supported to some extent, since, as expected, under conditions of military organization, more high authoritarians than low apparently accept or idealize their formally designated leader; and, attractive force of the group is apparently stronger for high than for low scorers on the authoritarianism scale. The strong positive association between leader acceptance and group cohesion, for high authoritarians, that is expected on the Frommian hypothesis is not found. A discussion of the Frommian compromise is then made. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychometric properties of the web-based work-readiness cognitive screen used as a neuropsychological assessment tool for schizophrenia

Traditional neuropsychological tests have been essential in understanding the nature and magnitude of the cognitive deficits associated with schizophrenia. However, current health care practices demand a more cost-effective and time-efficient assessment tool. This study investigates the psychometric properties of the work-readiness cognitive screen (WCS), a web-based neuropsychological measure, as a tool for screening cognitive impairment in schizophrenia, and examines diagnostic group differences in cognitive functioning between those with schizophrenia and affective disorders using the WCS. Data from 185 outpatients with schizophrenia or schizoaffective disorder and 29 outpatients with a mood disorder was analyzed in this study. The 185 people with schizophrenia were further divided into higher- and lower-functioning groups to assess cognition as it relates to daily functioning. People with schizophrenia demonstrated cognitive impairment on the WCS measures of attention, working memory, immediate and delayed visual memory, and verbal recognition memory. The higher-functioning schizophrenia group tended to perform better on the WCS cognitive domains than the low-functioning group. Reliability ranged from moderate to high. Working memory was found to be the most significant factor distinguishing diagnostic groups. These preliminary studies suggest that the WCS is a useful, time- and cost-effective cognitive screening measure for schizophrenia.     

Pattern recognition problems in the study of carbon black

This paper reviews certain pattern recognition problems associated with the study of carbon black. Two methods are described in which various properties are estimated by visual comparison with two-way charts. For studying fused aggregates, a new method of shape characterization has been developed, which should be of quite general utility. This method is based on representation of the silhouette of the aggregate as an ellipse with equivalent radii of gyration. Computer simulation is used to provide realistic models of aggregates, from which a relation is derived between the projected area of the silhouette (relative to that of a particle) and the volume of the aggregate. Automated methods are discussed for the determination of mean aggregate size and certain particle size parameters.     

A comparison of carbon black with soot

Carbon black is frequently confused with soot. In order to clarify the distinction between these materials, we have examined 6 carbon blacks and 18 samples of soot. Carbon black is composed of turbostratic colloidal aggregates which we call aciniform carbon (AC). Chimney soots from domestic wood or coal fires contain very little AC, while in diesel soots the solid particulates are essentially all AC. All soots examined contain much more extractable organic material and/or ash than does carbon black. Ames Salmonella assays were carried out on solvent extracts. The results were calculated as net revertants per mg of the original soot or carbon black. On this basis, the majority of the soot extracts assayed were at a much higher level of mutagenicity than any of the carbon black extracts. For several reasons, even greater differences in mutagen availability would be expected if the unextracted materials were compared in vivo.     

AFM imaging in solution of protein-DNA complexes formed on DNA anchored to a gold surface

A chemical procedure for anchoring DNA molecules to gold surfaces was used to facilitate the imaging of DNA and DNA-protein complexes in buffer solution by tapping mode atomic force microscopy (TMAFM). For preparing flat gold surfaces, a novel approach was employed by evaporating small amounts of gold onto freshly cleaved mica to give flat films that were stable under aqueous buffer conditions. The thickness of the investigated films ranged from 1 to 10 nm. For typical films of 4-6 nm, which were stable under aqueous buffer conditions, the root mean square (RMS) roughness ranged between 0.25 and 0.5 nm, as measured by atomic force microscopy (AFM). This roughness is comparable to that of obtained by the template stripped gold (TSG) technique, which is widely used in scanning probe microscopy but involves more preparation steps. In order to visualize DNA and DNA-protein complexes by TMAFM, the DNA was chemisorbed to the gold surface through a linker carrying a terminal thiol group at the 5'-end of each of the DNA strands. The modified DNA fragments were bound to the gold films and imaged in buffer solution, while unmodified DNA could not be visualized. Since the DNA was not dried during the process, it can be assumed that its native conformation was retained. This mode of anchoring did not prevent interaction with proteins, as confirmed by the observation that the topology of a complex formed by adding the protein to a surface-anchored DNA was the same as that obtained by anchoring a pre-formed complex to the gold surface. We attribute this observation to the fact that the DNA is anchored to the gold surfaces only through its ends, therefore the DNA-support interaction is minimized but imaging is still possible.     

Treatment of experimental mouse bladder tumour by LPS-induced epithelial cell shedding

The purpose of the present study was to explore the therapeutic potential of serial administration of shedding-inducing endotoxin in a mouse tumour bladder model. The studies were conducted with two variants derived from the MBT-2 tumour namely, T5 and T50, the latter being far more aggressive than the former. It was found that T5 tumours responded to intravesical lipopolysaccharides (LPS) instillation by a considerable reduction in their pace of growth (P < 0.0001) when treatment was initiated 3 days after tumour implantation, but not when started after 7 days. The T50 variant did not respond to LPS when treated 3 days after implantation, but a considerable reduction in rate of growth occurred when treatment was started after 1-2 days. Shedding induced by intravesically instilled LPS was found to retard considerably the progression rate of experimental bladder tumour.