Development and evaluation of a predictive model for the effect of temperature and water activity on the growth rate of Vibrio parahaemolyticus

The growth rates of four strains of Vibrio parahaemolyticus were measured and compared in a model broth system. The results for the fastest growing strain, based on 77 combinations of temperature and water activity (aw) using NaCl as the humectant, were summarised in the form of a predictive mathematical model. The model, of the square-root type includes a novel term to describe the effects of super-optimal water activity, and can be used to predict generation times for the temperature range (8-45 degrees C) and water activity range (0.936-0.995) which permit growth of Vibrio parahaemolyticus. Predicted generation times from the model were compared to literature data, using bias and accuracy factors, for both laboratory media and foods. The model was shown to give realistic growth estimates, with a bias value of 1.01, and an accuracy factor of 1.38.     

Magnetic resonance imaging of the normal mouse brain: comparison with histologic sections

Details in the living animal can be compared with respective histologic section taken after death. In less than 35 min, 12 to 16 coronal and transverse images through the brain can be obtained, each with an in-plane resolution of 100 x 200 microns and a slice thickness of 900 microns. The experimental parameters can be manipulated not only to achieve different tissue contrast but also to access any desired plane.     

Reversibility of changes in left and right ventricular geometry and hemodynamics in pulmonary hypertension. Echocardiographic characteristics before and after pulmonary thromboendarterectomy

Pulmonary thromboendarterectomy (PTE) leads to an acute decrease of right ventricular (RV) afterload in patients with chronic thromboembolic pulmonary hypertension. We investigated the changes in right and left ventricular (LV) geometry and hemodynamics by means of transthoracic echocardiography. The prospective study was performed in 14 patients (8 female, 6 male; age 55 +/- 20 years) before and 18 +/- 12 days after PTE. Total pulmonary vascular resistance and systolic pulmonary artery pressure were significantly decreased (PVR: preoperative 986 +/- 318, postoperative 323 +/- 280 dyn x s/cm5, p < 0.05; PAP preoperative 71 +/- 40, postoperative 41 +/- 40 mm Hg + right atrial pressure, p < 0.05). End diastolic and end systolic RV area decreased from 33 +/- 12 to 23 +/- 8 cm2, respectively, from 26 +/- 10 to 16 +/- 6 cm2, p < 0.05. There was an increase in systolic RV fractional area change from 20 +/- 12 to 30 +/- 16%, p < 0.05. RV systolic pressure rise remained unchanged (516 +/- 166 vs. 556 +/- 128 mm Hg/sec). LV ejection fraction remained within normal ranges (64 +/- 16 vs. 62 +/- 12%). Echocardiographically determined cardiac index increased from 2.8 +/- 0.74 to 4.1 +/- 1.74 l/min/m2. A decrease in LV excentricity indices (end diastolic: 1.9 +/- 1 vs. 1.1 +/- 0.3, end systolic: 1.7 +/- 0.6 vs. 1.1 +/- 0.4, p < 0.05) proved a normalization of preoperatively altered septum motion. LV diastolic filling returned to normal limits: (E/A ratio: 0.62 +/- 0.34 vs. 1.3 +/- 0.8; p < 0.05); Peak E velocity: 0.51 +/- 0.34 vs. 0.88 +/- 0.28 m/sec, p < 0.05; Peak A velocity: 0.81 +/- 0.36 vs. 0.72 +/- 0.42 m/sec, ns; E deceleration velocity: 299 +/- 328 vs. 582 +/- 294 cm/sec2, p < 0.05; Isovolumic relaxation time: 134 +/- 40 vs. 83 +/- 38 m/sec, p < 0.05). We could show a marked decrease in RV afterload shortly after PTE with a profound recovery of right ventricular systolic function--even in case of severe pulmonary hypertension. A decrease in paradoxic motion of the interventricular septum and normalization of LV diastolic filling pattern resulted in a significant increase of cardiac index.     

An algorithm for numerical calculation of the k-space data-weighting for polarly sampled trajectories: application to spiral imaging

Image reconstruction of data sampled into a non-uniform k-space grid requires appropriate data weighting and, for spiral-scan raw data, this weighting is usually calculated analytically under the assumption of uniform radial k-space sampling. This paper presents a simple and efficient algorithm for explicit numerical calculation of the data weighting for generalised polarly sampled k-space trajectories. The algorithm has been tested against both simulated data and data from experimental spiral-scan imaging and clearly provides significant improvements in image reconstruction when the radial uniformity of the k-space trajectory is poor.     

Protoporphyrinogen oxidase of Myxococcus xanthus. Expression, purification, and characterization of the cloned enzyme

Protoporphyrinogen oxidase (EC 1.3.3.4) catalyzes the six electron oxidation of protoporphyrinogen IX to protoporphyrin IX. The enzyme from the bacterium Myxococcus xanthus has been cloned, expressed, purified, and characterized. The protein has been expressed in Escherichia coli using a Tac promoter-driven expression plasmid and purified to apparent homogeneity in a rapid procedure that yields approximately 10 mg of purified protein per liter of culture. Based upon the deduced amino acid sequence the molecular weight of a single subunit is 49,387. Gel permeation chromatography in the presence of 0.2% n-octyl-beta-D-glucopyranoside yields a molecular weight of approximately 100,000 while SDS gel electrophoresis shows a single band at 50,000. The native enzyme is, thus, a homodimer. The purified protein contains a non-covalently bound FAD but no detectable redox active metal. The M. xanthus enzyme utilizes protoporphyrinogen IX, but not coproporphyrinogen III, as substrate and produces 3 mol of H2O2/mol of protoporphyrin. The apparent Km and kcat for protoporphyrinogen in assays under atmospheric concentrations of oxygen are 1.6 microM and 5.2 min-1, respectively. The diphenyl ether herbicide acifluorfen at 1 microM strongly inhibits the enzyme's activity.     

Smoking behaviour and attitudes among adult Saudi nationals in Riyadh City, Saudi Arabia

Nine massive hemipelvic allografts were used to reconstruct the pelvic ring and the hip articulation after resection of malignant tumors. At follow up of 3 to 10 years, six patients were free of oncologic disease. In the 3 acetabular massive allografts, functional results were close from those standard THR. After resection of hemipelvis and adjacent muscles, patients resume a normal family life (painless hip, poor active motion, walking with a crutch) with a functional result much better than after amputation. Considering these encouraging results in oncologic surgery, we used similar technics for reconstruction of very severe bone loss after iterative failures of THR revisions: some examples are reported at medium follow up.     

Evidence based practice: clinicians' use and attitudes to near patient testing in hospitals

AIM: To survey the use made of laboratory services for urgent tests and clinicians' attitudes to near patient testing. METHODS: A questionnaire was sent to clinicians working in acute hospitals within Trent and North West Thames Regions. RESULTS: 197 replies were received. Most demand came from intensive care units. Overall, clinicians requested a median of six urgent tests a day. Blood glucose and dip stick urine testing were the most commonly performed bedside tests, but 41% of clinicians did not use ward testing. The most frequently cited indication for bedside testing was the need for speed. 85% of clinicians trusted results obtained in their central hospital laboratory, but there was an almost equal division between those who did (34%) and those who did not (38%) trust the results from near patient testing. A slightly larger proportion indicated they would accept responsibility (44%) for results obtained on the ward than would not (35%). Most staff indicated that better transport to the laboratory would remove the need for near patient testing. CONCLUSIONS: Clinicians have demonstrated an apparent need for rapid response testing but there is a strong preference for rapid transport systems and central laboratory analysis rather than bedside testing as a solution to this problem. There is a need to investigate the clinical and cost-effectiveness of near patient testing as a solution to rapid response testing.     

Male factors in infertility--a preliminary report

Findings in 325 consecutive primary seminal analysis done at the Infertility Treatment Centre of IPGMR, are discussed. The clinical profile of the infertile couples was recorded. Semen was examined for quantity, sperm density, motility and morphology. An attempt was also made to correlate past illnesses with the quality of semen. 65 patients (20%) showed azoospermia, while 29 (8.9%) showed sperm count of less than 10 million/ml. History of past illnesses which contribute to azoospermia/oligospermia was obtained in 46% of azoospermia cases compared to only 10% in subjects showing sperm count of over 10 million/ml. Commonest association between azoospermia and past illness was found in the case of small-pox, where out of 31 subjects with past history of small-pox, 15 showed complete azoospermia, one showed sperm density of less then 10 million/ml.     

Structure and architecture of the bacterial virus fd. An infrared linear dichroism study

Oriented gels of intact bacterial virus fd have been invetigated by infrared linear dichroism. Infrared absorption band maxima and dichroism indicate an alpha-helix content of the major coat protein of 95-100%. The alpha-helical rods of the coat protein are aligned parallel to the long axis of the virion with an inclination roughly estimated to approximately 37 degree. The presence of DNA infrared bands at 968, 885, 830 and 799 cm-1, the absence of a band at 860 cm-1 and the perpendicular polarization of the symmetric PO-2 stretching vibration at 1085 cm-1 are all indicative of a B-type backbone conformation in the single-stranded DNA. We find no evidence for specific interaction between aromatic side groups (phenylalanine, tyrosine) and the DNA bases. Our results independently confirm most features of the model of Marvin and co-workers [2,15 ] based on low-resolution X-ray diffraction studies. However, our findings contradict their suggestion of an A-type DNA in the bacterial virus fd. Two results are consistent with rigid and stable order in the virus. First, over a 4-day period, 65% of the peptide hydrogens remain unexchanged with deuterium. Second, changes in the relative humidity of the sample do not result in any shifts in the DNA spectrum that are characteristic of free DNA.