Coronary arteries: retrospective cardiac gating technique to reduce cardiac motion artifact at spiral CT

Coronary artery calcification is a marker of atherosclerosis. Detection and quantification has previously been accomplished with electron-beam computed tomography (CT). Use of spiral CT for this application has been limited by cardiac motion. The authors evaluated a retrospective cardiac-gated postprocessing technique that necessitates no modification of scanner hardware or software. At spiral CT in 26 patients, motion artifact was reduced, coronary arteries were consistently visualized, and quantification of calcification could be performed in those patients with prominent deposits. Coronary artery calcification screening can therefore be offered in sites that have access to only spiral CT.     

Seasonal variation of blood pressure and its relationship to ambient temperature in an elderly population

OBJECTIVE: To measure the magnitude and timing of seasonal variation of blood pressure and related factors in the elderly living in the community, and to assess their potential impact on cardiovascular risk. DESIGN: Prospective study; from January 1991 to February 1992 blood pressure and other variables were measured at 2-monthly intervals in each subject in their own homes. SUBJECTS: Ninety-six men and women, age range 65-74 years, recruited from a single group general practice in Cambridge. MAIN OUTCOME MEASURES: Seasonal variation of blood pressure, seasonal variation of prevalence of hypertension, seasonal variation of ambient temperature and body mass index. RESULTS: Both systolic (SBP) and diastolic blood pressure (DBP) were greatest during the winter across the whole distribution of blood pressure. There was a fourfold increase in the proportion of subjects with blood pressures > 160/90 mmHg in winter compared with in summer. Regression analysis revealed highly significant seasonal differences in both SBP and DBP. After adjustment for confounding seasonal effects, a 1 degree C decrease in living-room temperature was associated with rises of 1.3 mmHg in SBP and 0.6 mmHg in DBP. CONCLUSIONS: Seasonal variation of blood pressure is heightened in older adults and may partly explain the greater cardiovascular disease mortality of elderly subjects during the winter. The blood pressures of elderly people may be inversely related to the ambient temperature. The public health implications of these findings deserve further investigation.     

Relationship of somatic cell count and cell volume analysis of goat's milk to intramammary infection with coagulase-negative staphylococci

The prevalence of intramammary infection in 4 commercial goat herds was studied in conjunction with electronic somatic cell count and volume analysis determined using a Coutler Counter and volume analyser. Neither streptococci nor mycoplasma were isolated from any half and the prevalence of intramammary infection with Staphylococcus aureus ranged from 0 to 3% between herds. For coagulase-negative staphylococci the range from infected halves was 36-71%. There was no significant difference between the mean total microscopic somatic cell count for halves infected with coagulase-negative staphylococci and those free from infection. A similar trend was observed for electronic somatic cell counts although the mean electronic cell count was greater than the mean total microscopic count on the 2 occasions that they were compared. The correlation coefficients between the 2 cell counting methods were 0.86 and 0.94. Between herds there were significant differences in mean electronic somatic cell count, with herd means ranging from 438 x 103 to 1684 x 103 cells/ml. In 2 of the 4 herds studied, milk samples from halves infected with coagulase-negative staphylococci had a significantly higher prevalence of cell volume distributions with a modal cell volume between 65 mu 3 and 100 mu 3. This was attributed to a higher proportion of polymorphonuclear neutrophils. Use of electronic somatic cell count and cell volume analysis were considered of little value in predicting infection caused by coagulase-negative staphylococci as there was a high proportion of false negative and false positive predictions.     

Hydrogen-induced cracking in two linepipe steels

Linepipe steels are susceptible to hydrogen-induced cracking (HIC) in wet, sour gas environments. Two commercially produced linepipe steels were investigated with regard to HIC on cathodic charging. Both steels, B and C, showed a high banded microstructure consisting of alternative layers of polygonal ferrite and a mixture of non-ferritic constituents (pearlite, bainite, and martensite-austenite). The degree of banding was higher in Steel B than in Steel C. Also present were elongated inclusions in Steel B, while in Steel C they were more or less equiaxed. On cathodically hydrogen-charging in the absence of external stress, microvoids formed at low current densities at or around inclusions. On prolonged charging, these voids grew and propagated parallel to the bands, running along the interface between ferrite/non-ferrite constituents, along inclusions lodged in the non-ferritic consitituents, and at places through the non-ferritic constituents. Steel B, not unexpectedly, showed more severe permanent microstructural damage than Steel C, leading to the conclusion that a high banded structure and/or the presence of elongated inclusions is deleterious to resistance against HIC.     

The ratio of the arithmetic to the geometric mean: a cross-entropyinterpretation

The ratio of the arithmetic mean to the geometric mean is often applied to synthetic aperture radar (SAR) imagery as a heuristic index of target homogeneity. It is shown that this ratio is equivalent to a cross entropy expression, and can therefore be interpreted as a measure of the information contained within the image     

Observations of scatterometer asymmetry over sand seas and derivation of wind ripple orientation

Over sand seas the ERS scatterometer has observed asymmetries similar to those found over open water. In this paper this asymmetric backscatter response is investigated using C-band VV data from the ERS scatterometer and the data are analysed using a simple empirical model combined with quick-look Synthetic Aperture Radar (SAR) data to provide information on dune type and orientation. The results suggest that the azimuthal response is sensitive to the orientation of small-scale (millimetres to metres) wind-induced sand ripples, rather than the larger scale dune orientation. Additionally, the study investigates the feasibility of using such observations to determine ripple orientation over areas of active sand.     

Ultrasound biometry in the diagnosis of amblyopia in keratoconus.

Here, we describe a case in which A-scan ultrasound biometry was used to differentially diagnose the cause of reduced vision in a patient with keratoconus. A patient with keratoconus presented with reduced visual acuity in one eye, not improvable above 6/18 with specialist keratoconus contact lens fitting. This monocular amblyopia was attributed to previous anisometropic ametropia by the use of ultrasound biometry. The report demonstrates the usefulness of ultrasound biometry in the detection of amblyopia in circumstances in which a previous assessment of amblyopia is not possible. This information will impact upon decisions made for the future clinical management in this case, especially if vision deteriorates so that a corneal graft is required.     

A comparison of morphine, pethidine and fentanyl in the postsurgical patient-controlled analgesia environment

Oncogene and tumor suppressor gene mutations are candidate biomarkers for cancer risk assessment and lesion detection. The K-ras oncogene has previously been associated with non-small cell lung cancer (NSCLC), particularly adenocarcinomas in which reported rates of mutation have approached 30-40%. We have analyzed non-malignant lung tissue from patients with lung cancer and primary lung cancers for K-ras gene mutations. Mutations were detected in 32% cancers and 29% non-malignant lung tissue from patients with cancer. The majority of tumors testing positive were adenocarcinoma of the lung. Normal DNA controls, including peripheral blood lymphocytes and normal lung from non-smokers, were negative. The ability to detect genetic alterations in non-malignant lung tissues is consistent with the concept that genetic alterations are involved in field cancerization of the aerodigestive tract.     

Cell volume to aid analysis and technique of somatic cell counts in milk.

In conjunction with a Coulter Counter, somatic cells in milk were sized by electronic analysis. Quarter milk from cows with mastitis had a cell volume peak with a modal cell volume of 102 mu3 while milk from healthy quarters had no peak. Bulk milks with a peak had higher cell counts than milks where there was no peak. Dimensions of peak from bulk milks were the same as from quarter milks. Modal cell volume and cell count varied after milks were fixed with varying concentrations and types of fixative. The concentration of fixative recommended by the International Dairy Federation was sufficient, but only marginally so, and it should be increased.