Light scattering from normal and dysplastic cervical cells at different epithelial depths: finite-difference time-domain modeling with a perfectly matched layer boundary condition

The finite-difference time-domain (FDTD) method provides a flexible approach to studying the scattering that arises from arbitrarily inhomogeneous structures. We implemented a three-dimensional FDTD program code to model light scattering from biological cells. The perfectly matched layer (PML) boundary condition has been used to terminate the FDTD computational grid. We investigated differences in angle-dependent scattering properties of normal and dysplastic cervical cells. Specifically, the scattering patterns and phase functions have been computed for normal and dysplastic cervical cells at three different epithelial depths, namely, basal/parabasal, intermediate, and superficial. Construction of cervical cells within the FDTD computational grid is based on morphological and chromatin texture features obtained from quantitative histopathology. The results show that angle-dependent scattering characteristics are different not only for normal and dysplastic cells but also for cells at different epithelial depths. The calculated scattering cross-sections are significantly greater for dysplastic cells. The scattering cross-sections of cells at different depths indicate that scattering decreases in going from the superficial layer to the intermediate layer, but then increases in the basal/parabasal layer. This trend for epithelial cell scattering has also been observed in confocal images of ex vivo cervical tissue.     

Prion susceptibility and protective alleles exhibit marked geographic differences

A total of 616 chromosomes from control individuals of all major continental groups, and six individuals affected by either Creutzfeldt-Jakob disease (CJD) or fatal familial insomnia (FFI), were typed with a new single-reaction protocol method and were also sequenced, with total reproducibility to screen variation at important positions (385A>G: M129V and 655G>A: E219K) in the human prion protein gene (PRNP). We have found, for the first time, that 129V allele is highly represented in some populations from the Americas, and that 129M and 129V are in similar frequencies in Africa. The 129M susceptibility allele was found at high frequencies in Old World populations, very high in the Pacific ( approximately 81%) and up to 93% in Central and East Asia, but at a low frequency (approximately 30%) in Native Americans. The protective 219L allele was restricted to Asian and Pacific populations. Susceptibility alleles exhibit marked geographic differences in frequency, and thus, differences in probability to develop prion diseases.     

Ultrastructural changes in prostate cells during hormone-induced canine prostatic hyperplasia

Benign prostatic hyperplasia is a prevalent disease that has received relatively little attention in spite of its morbidity and remarkable social impact. There are few animal models of prostatic hyperplasia. The dog is the only species, along with humans, in which prostatic hyperplasia develops spontaneously and almost universally with age. The aim of the present study has been to compare the ultrastructural findings in a model of experimentally induced canine prostatic hyperplasia with those of the spontaneously developed changes in untreated dogs. An experimental group of 5 male beagle dogs were castrated and treated with combined steroids (3 weekly doses for over 30 weeks). Prostate samples were surgically obtained every 42 days (experimental stages 0 through 6). The control group consisted of 3 noncastrated dogs that were treated with vehicle and in which samples were taken only at stages 0, 1, 4, and 6. Changes in the control groups were similar but of lower intensity compared to those of the experimental groups. In luminal cells, crowding with papillary projections, prominent, branching microvilli, and abundant, often compartmentalized granules were observed. The most striking change was the previously unreported finding of caveolae in basal cells. They were mostly located in the basal aspect of basal cells and were more prominent in the experimental group and in advanced stages of treatment. These ultrastructural findings have not been previously reported in canine or human prostatic hyperplasia and merit further research. The model of experimentally induced canine prostatic hyperplasia provides an adequate setting for the understanding of this disease.     

Myocardial lactate metabolism at rest and during exercise in ischemic heart disease

Cardiac dynamics and myocardial extraction of oxygen and lactate were investigated at rest in subjects with normal coronary arteries and in patients with coronary heart disease. Coronary artery disease was considered significant when there was obstruction or more than 50 per cent narrowing of one or more coronary arteries. Half of the patients were also studied during moderate exercise. The hemodynamic findings were almost comparable in all cases. On exercise, in patients with significant coronary disease, there was evidence of abnormal left ventricular function, and increases in cardiac index were mediated through a much higher left ventricular end-diastolic pressure.

Coronary arteriovenous difference and the myocardial extraction of oxygen were normal at rest and unchanged on exercise in all cases. Marked rise in the arterial level and a significant increase in the arteriovenous difference of lactate were present in all cases. The extraction ratio of lactate by the myocardium remained normal and increased only slightly in control subjects. However, this ratio increased to normal levels during exercise in all patients with significant coronary artery disease. Possible explanations for the increased coronary arteriovenous difference and myocardial extraction ratio of lactate on exercise in these patients are discussed.     

Salivary cortisol profiles in patients remitted from recurrent depression: one-year follow-up of a mindfulness-based cognitive therapy trial

Few studies have examined changes of diurnal cortisol profiles prospectively, in relation to non-pharmacological interventions such as mindfulness-based cognitive therapy (MBCT). Fifty-six patients remitted from recurrent depression (≥3 episodes) were included in an 8-week randomized controlled trial comparing MBCT plus treatment as usual (TAU) with TAU for depression relapse prophylaxis. Saliva samples (0, 15, 30, 45, 60 min post-awakening, 3 PM, 8 PM) were collected on six occasions (pre- and post-intervention, 3-, 6-, 9-, 12-month follow-up). Cortisol awakening response (CAR), average day exposure (AUCday) and diurnal slope were analyzed with mixed effects models (248 profiles, 1-6 per patient). MBCT (n = 28) and TAU groups (n = 28) did not significantly differ with respect to baseline variables. Intra-individual variability exceeded inter-individual variability for the CAR (62.2% vs. 32.5%), AUC(day) (30.9% vs. 23.6%) and diurnal slope (51.0% vs. 34.2%). No time, group and time by group effect was observed for the CAR and diurnal slope. A significant time effect (p = 0.003) was detected for AUCday, which was explained by seasonal variations (p = 0.012). Later wake-up was associated with lower CAR (-11.7% per 1-hour later awakening, p < 0.001) and lower AUCday (-4.5%, p = 0.014). Longer depression history was associated with dampened CAR (-15.2% per 10-year longer illness, p = 0.003) and lower AUCday (-8.8%, p = 0.011). Unchanged cortisol secretion patterns following participation in MBCT should be interpreted with regard to large unexplained variability, similar relapse rates in both groups and study limitations. Further research is needed to address the scar hypothesis of diminished HPA activity with a longer, chronic course of depression.     

Comparación entre tromboelastografía y test de coagulación convencionales: ¿deberíamos abandonar los test de coagulación convencional en el paciente politraumatizado?

Introduction

TEG provides an in-vivo assessment of viscoelastic clot strength in whole blood compared with CCT, which may not reflect the influence of platelets. The aim of this study was to compare TEG vs. CCT in trauma patients stratified by mechanism of injury (MOI) and pre-existing coagulation status.

Interassay reproducibility of myocardial perfusion gated SPECT in patients with atrial fibrillation

Aim  

The aim of this study was to assess interassay reproducibility of myocardial perfusion gated-SPECT for calculation of end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF) in patients with atrial fibrillation (AF).     

The effect on early renal function of various dynamic preservation strategies in a preclinical pig ischemia–reperfusion autotransplant model

The aims of this study were to determine the most optimal timing to start machine perfusion during kidney preservation to improve early graft function and to evaluate the impact of temperature and oxygen supply during machine perfusion in a porcine ischemia–reperfusion autotransplant model. The left kidney of an approximately 40‐kg female Belgian Landrace pig was exposed to 30 minutes of warm ischemia via vascular clamping and randomized to 1 of 6 study groups: (1) 22‐hour static cold storage (SCS) (n = 6), (2) 22‐hour hypothermic machine perfusion (HMP) (n = 6), (3) 22‐hour oxygenated HMP (n = 7), (4) 20‐hour HMP plus 2‐hour normothermic perfusion (NP) (n = 6), (5) 20‐hour SCS plus 2‐hour oxygenated HMP (n = 7), and (6) 20‐hour SCS plus 2‐hour NP (n = 6). Graft recovery measured by serum creatinine level was significantly faster for continuous HMP preservation strategies compared with SCS alone and for all end‐ischemic strategies. The active oxygenated 22‐hour HMP group demonstrated a significantly faster recovery from early graft function compared with the 22‐hour nonactive oxygenated HMP group. Active oxygenation was also found to be an important modulator of a faster increase in renal flow during HMP preservation. Continuous oxygenated HMP applied from the time of kidney procurement until transplant might be the best preservation strategy to improve early graft function.     

Brain tumor classification by proton MR spectroscopy: comparison of diagnostic accuracy at short and long TE

BACKGROUND AND PURPOSE: Different TE can be used for obtaining MR spectra of brain tumors. The purpose of this study was to determine the influence of the TE used in brain tumor classification by comparing the performance of spectra obtained at two different TE (30 ms and 136 ms). METHODS: One hundred fifty-one studies of patients with brain tumors (37 meningiomas, 12 low grade astrocytomas, 16 anaplastic astrocytomas, 54 glioblastomas, and 32 metastases) were retrospectively selected from a series of 378 consecutive examinations of brain masses. Single voxel proton MR spectroscopy at TE 30 ms and 136 ms was performed with point-resolved spectroscopy in all cases. Fitted areas of nine resonances of interest were normalized to water. Tumors were classified into four groups (meningioma, low grade astrocytoma, anaplastic astrocytoma, and glioblastoma-metastases) by means of linear discriminant analysis. The performance of linear discriminant analysis at each TE was assessed by using the leave-one-out method. RESULTS: Tumor classification was slightly better at short TE (123 [81%] of 151 cases correctly classified) than at long TE (118 [78%] of 151 cases correctly classified). Meningioma was the only group that showed higher sensitivity and specificity at long TE. Improved results were obtained when both TE were considered simultaneously: the suggested diagnosis was correct in 105 (94%) of 112 cases when both TE agreed, whereas the correct diagnosis was suggested by at least one TE in 136 (90%) of 151 cases. CONCLUSION: Short TE provides slightly better tumor classification, and results improve when both TE are considered simultaneously. Meningioma was the only tumor group in which long TE performed better than short TE.     

Pretransplantation diagnosis and staging of hepatocellular carcinoma in patients with cirrhosis: value of dual-phase helical CT

OBJECTIVE: The objective of our study was to prospectively evaluate the results of helical CT in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis undergoing orthotopic liver transplantation. SUBJECTS AND METHODS. Eighty-five patients with cirrhosis were studied preoperatively with biphasic helical CT. Arterial, portal, and equilibrium phase images were obtained after injection of 170 mL of contrast material at 5 mL/sec. The prospective CT interpretation was compared with pathologic results on a lesion-by-lesion basis. RESULTS: Pathologic examination found 85 cases of HCC in 51 patients. Helical CT enabled a correct diagnosis of HCC in 67 of 85 lesions for a sensitivity of 78.8%. HCC nodules were hypervascular in the arterial phase and hypovascular in the equilibrium phase in 63.5% (54/85) of patients. The false-negative rate was 21% (n = 18), and the positive predictive value was 88%. We had nine false-positive findings (11.8%) related to hemangiomas, transient hepatic attenuation differences, and regenerative nodules. Helical CT detected 61% (23/38) of lesions smaller than 2 cm and 93.6% (44/47) of lesions 2 cm or larger. CONCLUSION: Helical CT is a useful preoperative imaging technique in cirrhotic patients who are candidates for orthotopic liver transplantation, although it is relatively insensitive for detection of small lesions (< 2 cm).